Emergency call method and apparatus

Abstract

The embodiments of the present application relate to the field of communications. Provided are an emergency call method and apparatus, which can improve the success rate of emergency calls. The method is applied to a terminal device. The terminal device is registered with a communication network of a home operator. The method comprises: receiving a user's operation of dialing an emergency number, and when a preset condition is met, searching for a communication network of a non-home operator that supports an IMS emergency call, wherein the preset condition comprises a failure of a terminal device to register with an IMS network of a home operator; and when the communication network of the non-home operator that supports the IMS emergency call is found, the terminal device performing emergent registration with an IMS network of the non-home operator, and sending an INVITE message to the IMS network of the non-home operator, wherein the INVITE message comprises an emergency identifier corresponding to the emergency number.

Description

Emergency call method and device

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office on April 12, 2024, with application number 202410448541.4 and invention name “A Method and Device for Emergency Calling”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The embodiments of the present application relate to the field of communications, and in particular to an emergency call method and apparatus. Background Art

[0003] Emergency calls are a voice service in fixed-line and mobile communications. Users can initiate an emergency call by dialing an emergency number (e.g., 110, 112, 911, etc.). Emergency calls are forwarded to the appropriate public safety answering point (PSAP), such as a police station, fire department, or emergency medical services center, which provides 24-hour emergency assistance. The entire process is coordinated by telecommunications operators and emergency service agencies such as the police, fire department, and hospitals.

[0004] When a terminal device (e.g., a mobile phone) is in the second generation (2 th generation, 2G) or third generation (3 th When the mobile phone is registered on the fourth generation (4G) mobile communication network, emergency calls can be made in the circuit switching (CS) domain. th generation, 4G) or fifth generation (5 th When registering with a 5G (5G generation) mobile communication network, emergency calls can be implemented in the packet switching (PS) domain, using the IP multimedia subsystem (IMS) to perform signaling plane control on the emergency session.

[0005] However, when the mobile phone is registered in a 4G or 5G network, a problem that the operator does not support an emergency call in an IMS network can occur. At this time, when the user dials an emergency call number, although a user interface (UI) of the mobile phone displays that the current call is an emergency call, a Modem of the mobile phone adopts a normal call process (see FIG. 2). Such an emergency call can be referred to as a false emergency call. If the operator supports an emergency call in an IMS network, when the user dials an emergency call number, not only does the UI of the mobile phone display that the current call is an emergency call, but also the Modem of the mobile phone adopts an emergency call process (see FIG. 1). Such an emergency call can be referred to as a true emergency call. For a false emergency call, if the mobile phone fails to register in an IMS network, a call session cannot be established based on an IMS normal call process, and ultimately the emergency call fails. SUMMARY

[0006] Embodiments of the present application provide an emergency call method and device, which can improve the success rate of an emergency call.

[0007] To achieve the above object, embodiments of the present application adopt the following technical solutions:

[0008] In a first aspect, an emergency call method is provided, applied to a terminal device, the terminal device being registered in a communication network of a home operator, and the method comprising: receiving an operation of dialing an emergency number by a user, searching for a communication network of a non-home operator supporting an IMS emergency call in a case where a preset condition is met; the preset condition comprising a failure of the terminal device in registering in an IMS network of the home operator; in a case where the communication network of the non-home operator supporting the IMS emergency call is searched, the terminal device is registered in an IMS network of the non-home operator in an emergency, and an INVITE message is sent to the IMS network of the non-home operator, the INVITE message comprising an emergency identifier corresponding to the emergency number.

[0009] Based on the method provided by the embodiments of the present application, in a case where the terminal device fails to register in an IMS network of a home operator, the terminal device can search for a communication network of a non-home operator supporting an IMS emergency call, and in a case where the communication network of the non-home operator supporting the IMS emergency call is searched, the terminal device can register in an IMS network of the non-home operator (a foreign network IMS network) in an emergency and make an emergency call, thereby improving the success rate of an emergency call.

[0010] In a possible implementation, the preset condition further includes: the terminal device fails to search a circuit switched (CS) network of the home operator or the terminal device does not support a CS capability. That is, before the terminal device searches a communication network of a non-home operator supporting an IMS emergency call, the terminal device can search a CS network of the home operator, so that the call is initiated in the CS network of the home operator, and the success rate of the emergency call can be improved. When the terminal device fails to search the CS network of the home operator or the terminal device does not support the CS capability, the terminal device searches the communication network of the non-home operator supporting the IMS emergency call, so that the emergency registration and the emergency call are performed in the IMS network of the non-home operator, and the success rate of the emergency call is improved.

[0011] In a possible implementation, the searching of the communication network of the non-home operator supporting the IMS emergency call includes: receiving, by the terminal device, a system information block (SIB) of a cell of the non-home operator; and determining, by the terminal device, whether the cell of the non-home operator supports the IMS emergency call according to the SIB. In some embodiments, if an IMS emergency support flag exists in the SIB message, the network in the cell can support the IMS emergency call of the UE. If the IMS emergency support flag does not exist in the SIB message, the network in the cell does not support the IMS emergency call of the UE. In other embodiments, the SIB message includes an IMS emergency support flag, and the IMS emergency support flag indicates whether the cell supports the IMS emergency bearer service of the UE. In this way, the terminal device can determine whether the cell of the non-home operator supports the IMS emergency call according to the SIB, so that the emergency registration and the emergency call are performed in the IMS network of the non-home operator, and the success rate of the emergency call is improved.

[0012] In a possible implementation, the terminal device preconfigures a public land mobile network (PLMN) list including a PLMN supporting the IMS emergency call, and the searching of the communication network of the non-home operator supporting the IMS emergency call includes: performing, by the terminal device, a cell search according to the PLMN list. In this way, the terminal device can determine whether the cell of the non-home operator supports the IMS emergency call according to the PLMN list, so that the emergency registration and the emergency call are performed in the IMS network of the non-home operator, and the success rate of the emergency call is improved.

[0013] In a possible implementation, before the terminal device performs the emergency registration to the second IMS network of the non-home operator, the method further includes: performing, by the terminal device, an emergency registration to a communication network of the non-home operator; and establishing, by the terminal device, an emergency packet data network (PDN) connection or an emergency protocol data unit (PDU) connection with the communication network of the non-home operator.

[0014] In a possible implementation, the emergency registration of the terminal device to the second IMS network of the non-homeland operator comprises: the terminal device sends an emergency registration request to the second IMS network, the emergency registration request comprising an emergency field; and the terminal device receives a 200 OK response message from the second IMS network.

[0015] In a possible implementation, the registration failure of the terminal device in the IMS network of the homeland operator comprises: the registration failure of the terminal device in the IMS network of the homeland operator in the case that the terminal device is registered in the 4G network of the homeland operator; or the registration failure of the terminal device in the IMS network in the case that the terminal device is registered in the 5G network of the homeland operator, and the registration failure of the terminal device in the IMS network of the homeland operator after the terminal device switches (the switch can also be understood as fallback) from the 5G network of the homeland operator to the 4G network of the homeland operator. That is, the terminal device registers in the 4G network or the 5G network of the homeland operator, and the registration in the IMS network fails. Then, the terminal device can search for the communication network of the non-homeland operator supporting IMS emergency call, and in the case that the communication network of the non-homeland operator supporting IMS emergency call is searched, the terminal device can perform emergency registration and emergency call in the IMS network of the non-homeland operator, thereby improving the success rate of emergency call.

[0016] In a second aspect, a terminal device is provided, comprising: a processor and a memory; the memory stores computer-executed instructions; and the processor executes the computer-executed instructions stored in the memory, so that the terminal device performs the method described in any one of the possible implementation manners of the first aspect.

[0017] In a third aspect, a chip system is provided, comprising at least one processor and at least one interface, the interface and the processor being interconnected through a line, and the at least one processor being configured to run a computer program or instructions to perform the method described in any one of the possible implementation manners of the first aspect.

[0018] In a fourth aspect, a computer readable storage medium is provided, and the computer readable storage medium stores a computer program. The computer program is executed by a processor to implement the method described in any one of the possible implementation manners of the first aspect.

[0019] In a fifth aspect, a computer program product is provided, and the computer program product comprises a computer program. When the computer program is executed, the computer program causes a computer to perform the method described in any one of the possible implementation manners of the first aspect.

[0020] It can be understood that the terminal device provided in the second aspect, the chip system provided in the third aspect, the computer readable storage medium provided in the fourth aspect, and the computer program product provided in the fifth aspect are all used to execute the method as described in any one of the implementation manners of the first aspect. Therefore, the beneficial effects that can be achieved thereby can refer to the beneficial effects of any one of the possible implementation manners of the first aspect, which will not be described here again. BRIEF DESCRIPTION OF DRAWINGS

[0021] FIG. 1 is a signal interaction schematic diagram of an IMS emergency call flow provided by an embodiment of the present application;

[0022] FIG. 2 is a signal interaction schematic diagram of an IMS ordinary call flow provided by an embodiment of the present application;

[0023] FIG. 3 is a schematic diagram of a communication system architecture provided by an embodiment of the present application;

[0024] FIG. 4 is a schematic diagram of a voice call scenario provided by an embodiment of the present application;

[0025] FIG. 5 is a flow schematic diagram of an emergency call method provided by an embodiment of the present application;

[0026] FIG. 6 is a display schematic diagram provided by an embodiment of the present application;

[0027] FIG. 7 is a signal interaction schematic diagram of an emergency call method provided by an embodiment of the present application;

[0028] FIG. 8 is a signal interaction schematic diagram of another emergency call method provided by an embodiment of the present application;

[0029] FIG. 9 is a hardware structure schematic diagram of a terminal device provided by an embodiment of the present application;

[0030] FIG. 10 is a software architecture schematic diagram of a terminal device provided by an embodiment of the present application;

[0031] FIG. 11 is a structure schematic diagram of a chip system provided by an embodiment of the present application. DETAILED DESCRIPTION

[0032] For the sake of clear and concise description of each embodiment below, first, a brief introduction of related concepts or technologies is given:

[0033] Emergency call number: refers to a public number specified by each country for a person in distress to call for help in an emergency. Taking China as an example, it includes international general emergency numbers such as 911 and 112, and national required emergency numbers such as 110, 119, 120, and 122.

[0034] The emergency call number can be divided into a true emergency call number and a false emergency call number.

[0035] When a real emergency call number is dialed, not only the UI of the terminal device (e.g., a mobile phone) displays the current call as an emergency call, but also the mobile phone establishes a call session through an emergency call procedure.

[0036] When a false emergency call number is dialed, although the UI of the mobile phone displays the current call as an emergency call, the mobile phone establishes a call session through a normal call procedure.

[0037] Whether an emergency call number is a real emergency call number or a false emergency call number can be determined based on network configuration and operator requirements of an operator. For example, for emergency call numbers 110, 119, 120, and 122, etc., China Mobile, China Radio and Television, and China Unicom, etc. operators, because their networks do not support IMS emergency calls, all regard them as false emergency call numbers, while China Telecom regards them as real emergency call numbers because it supports IMS emergency calls.

[0038] For example, as shown in FIG. 1, in an IMS emergency call procedure, even if the UE has completed IMS registration, when the user initiates an emergency call (i.e., the UE receives an emergency number dialed by the user), the UE still needs to send an IMS emergency registration request (sip register) to the IMS network. The contact header field of the emergency registration request carries the SOS field (emergency field). After the IMS network receives the emergency registration request sent by the UE, it can reply a 200 OK response message to complete the IMS emergency registration. Then, the UE can send an INVITE message to the IMS network for calling the emergency number. The INVITE message includes an emergency identifier corresponding to the emergency number (e.g., an emergency identifier urn:service:sos.police corresponding to the emergency number 110). At this time, the IMS emergency call is formally initiated.

[0039] For example, as shown in FIG. 2, in an IMS normal call procedure, if the user has completed IMS registration, the UE can directly send an INVITE message to the IMS network and carry a target number (i.e., a dialed number) to initiate a call.

[0040] Currently, the global 2G network and 3G network are gradually being retired, and the 4G network and 5G network are in the ascendant. When the mobile phone is registered in the 4G or 5G network, the problem of the operator not supporting the IMS emergency call (i.e., the operator to which the SIM card of the mobile phone belongs does not support the IMS emergency call) may occur. At this time, when the user dials an emergency call number, although the UI of the mobile phone displays the current call as an emergency call, the Modem of the mobile phone adopts an IMS normal call procedure. In this case, if the mobile phone fails to register in the IMS network, the mobile phone cannot establish a call session based on the IMS normal call procedure, which eventually leads to the failure of the emergency call.

[0041] For example, in the case that the operator to which the SIM card of the mobile phone belongs is China Mobile, when the user dials "120" through the mobile phone, since the network of China Mobile does not support IMS emergency call, the mobile phone regards "120" as a false emergency call number. Assuming that the mobile phone fails to register on the IMS network, the mobile phone cannot establish a call session based on the IMS normal call process, and finally results in failure of the emergency call.

[0042] The embodiment of the present application provides an emergency call method, which can avoid the problem that the emergency call fails due to the fact that the operator does not support IMS emergency call, thereby improving the success rate of the emergency call.

[0043] In order to better understand the emergency call method and related device provided by the embodiment of the present application, the network architecture of the embodiment of the present application is described below.

[0044] As shown in FIG. 3, it is a communication system architecture diagram provided by the embodiment of the present application. The communication system includes a terminal device, a home 4G / 5G access network, a foreign 4G / 5G access network, a home 4G / 5G core network, a foreign 4G / 5G core network, a home IMS network and a foreign IMS network. Optionally, the communication system can further include a home CS network. The specific introduction is as follows:

[0045] (1) terminal device: can be a calling terminal device (or called calling side terminal device). The terminal device can also be called terminal, user equipment (UE), user terminal, mobile station (MS), mobile terminal (MT), etc. The terminal device can be a handheld terminal, a notebook computer, a subscriber unit, a cellular phone, a smart phone, a wireless data card, a personal digital assistant (PDA) computer, a tablet computer, a handheld device, a laptop computer, a cordless phone or a wireless local loop (WLL) station, a machine type communication (MTC) terminal, a wearable device (such as a smart watch, a smart bracelet, a pedometer, etc.), a vehicle-mounted device (such as a car, a bicycle, an electric vehicle, an airplane, a ship, a train, a high-speed rail, etc.), a virtual reality (VR) device, an augmented reality (AR) device, a wireless terminal in industrial control, a smart home device (such as a refrigerator, a television, an air conditioner, an electricity meter, etc.), a smart robot, a workshop device, a wireless terminal in self driving, a wireless terminal in remote medical surgery, a wireless terminal in smart grid, a wireless terminal in transportation safety, a wireless terminal in smart city, a wireless terminal in smart home, a flight device (such as a smart robot, a drone) or a wireless terminal in future communication network, etc. The embodiments of the present application do not make specific limitations thereto. In the embodiments of the present application, the terminal device can be a terminal device sold independently or a chip in the terminal device. In the technical solutions provided by the embodiments of the present application, the device for realizing the functions of the terminal device is taken as an example of the independent terminal device to describe the technical solutions provided by the embodiments of the present application.

[0046] The terminal device stores user information, which can include an international mobile subscriber identification number (IMSI). The IMSI can be stored in a subscriber identity module (SIM) card of the terminal device. The terminal device can use the user information as an identity to initiate or receive a call through various voice solutions.

[0047] (2) In-network 4G / 5G access network: The in-network access network can refer to the access network of the home operator of the terminal device. The home operator of the terminal device can refer to the operator to which the SIM card of the terminal device belongs. The in-network access network can include the wireless access network of the 4G network (i.e., the LTE network) and the wireless access network of the 5G network (i.e., the NR network).

[0048] (3) Out-of-network 4G / 5G access network: The out-of-network access network can refer to the access network of the non-home operator of the terminal device. The out-of-network access network can include the wireless access network of the 4G network and the wireless access network of the 5G network.

[0049] It can be understood that the in-network access network and the out-of-network access network are both access networks. The access network is responsible for connecting end users to the core network (also known as the backbone network) one by one using some wired or wireless connection and communication technology, and realizing connection with the network. The access network is the edge part of the entire network, and is the part closest to the user, which is usually also called the “last mile”.

[0050] The access network part of the 4G network can be referred to as an evolved UMTS terrestrial radio access network (E-UTRAN). The terminal device can access the access network part of the 4G network through a 4G base station. The 4G base station can be an evolved NodeB (eNB or eNodeB) in long term evolution (LTE).

[0051] The access network part of the 5G network can be referred to as a Next Generation Radio Access Network (NG-RAN or NG RAN). The terminal device can access the access network part of the 5G network through a 5G base station. The 5G base station can be a gNodeB (gNB) in new radio (NR). The base station in NR can also be referred to as a transmission reception point (TRP).

[0052] (4) Home network 4G / 5G core network: The home network core network can refer to the core network of the home operator of the terminal device. The home network core network can include the core network of the 4G network and the core network of the 5G network. Optionally, the home network core network can also include the core network of the 2G network and the 3G network.

[0053] (5) Foreign network 4G / 5G core network: The foreign network core network can refer to the core network of a non-home operator of the terminal device. The foreign network core network can include the core network of the 4G network and the core network of the 5G network.

[0054] It can be understood that the home network core network and the foreign network core network are both core networks. The main function of the core network is to provide user connection, management of users, and completion of bearer for services, and to provide an interface to external networks as a bearer network. The establishment of user connection includes functions such as mobility management (MM), call management (CM), switching / routing, voice notification (connection relationship to intelligent network peripherals is completed in combination with intelligent network services), and the like.

[0055] It can be understood that the core network of the 4G network is an evolved packet core (EPC) network. The EPC network has traditional capabilities of mobile networks such as user subscription data storage, mobility management, and data exchange, and can provide users with a super-fast online experience. The core network of the 5G network is 5G Core (which can be referred to as 5GC). The 5GC can use general network function virtualization devices to replace the dedicated communication devices of the 4G network.

[0056] It should be noted that the core network (the home core network or the foreign core network) in the network architecture shown in FIG. 3 can be obtained by fusing the EPC and the 5GC. That is, the core network in the network architecture can include network elements in the EPC and network elements in the 5GC. For example, the core network in the network architecture can include an access and mobility management function (AMF) network element, a mobility management entity (MME) network element, a serving gateway (SGW) network element, a packet data network gateway (PGW) network element, a session management function (SMF) network element, a user plane function (UPF) network element, a unified data management (UDM) network element, and a home subscriber server (HSS) network element, and the like.

[0057] In some embodiments of the present application, the core network in the network architecture can include a fused network element obtained by network elements in the EPC and network elements in the 5GC. For example, SMF+PGW-C, UPF+PGW-U, UDM+HSS, and the like. Among them, PGW-C is a control plane node of the PGW network element, and PGW-U is a user plane node of the PGW network element.

[0058] Each network element in the core network can also be referred to as a functional entity, which can be a network element implemented on a dedicated hardware, a software instance running on a dedicated hardware, or an instance of a virtualized function on a suitable platform.

[0059] It should be understood that the names of all network elements in the present application are only examples. In future communications, such as 6G, they can also be referred to by other names, or in future communications, such as 6G, the network elements involved in the present application can also be replaced by other entities or devices with the same function, and the like, which are not limited in the present application. Here, a unified description is made, and subsequent details are not repeated. Optionally, various network elements in the embodiments of the present application can be communication devices, or can be chips or chip systems that can be used in the communication devices, and the like, which are not limited in the embodiments of the present application.

[0060] It can be understood that the core network in the network architecture shown in FIG. 3 can further include other devices, network elements, network entities or network subsystems, such as a policy control function (PCF) network element, which is not limited in the present application. It should be noted that the distribution of each network element in the core network is not limited in the present application, and can be referred to related technical documents for specific distribution, which will not be described herein.

[0061] (6) Home network IMS network: The home network IMS network can refer to the IMS network of the home operator of the terminal device.

[0062] (7) Foreign network IMS network: The foreign network IMS network can refer to the IMS network of the non-home operator of the terminal device.

[0063] It can be understood that the IMS network is a network architecture based on an internet protocol (IP) network to provide voice and multimedia communication services (such as voice, video and text messages, etc.), that is, an IP multimedia subsystem (IP multimedia subsystem). The IMS network can realize safe and reliable multimedia communication between different devices of different networks. The architecture model provides a unified infrastructure and a general mechanism for controlling, operating, routing and managing sessions, and realizing identity verification, authorization and accounting control. The IMS specification includes widely used internet engineering task force (IETF) recommendations. For example, a session initialization protocol (SIP) for session control signaling.

[0064] In some embodiments of the present application, the IMS network in the network architecture shown in FIG. 3 can include a proxy session border control (PSBC) network element, which is a combined network element of a session border control (SBC), a Proxy-CSCF (P-CSCF), an access transfer control function (ATCF), and an access transfer gateway (ATGW). As an SBC network element, it connects the IMS core network / softswitch network and an external user access area, completes service access of IMS / softswitch users, realizes interworking of user services in different network environments, guarantees IMS / softswitch network security, supports QoS management, CAC traffic control, media management, CDR media call detail, and the like.

[0065] (8) In-network CS network: The in-network CS network can refer to a CS network of a home operator of a terminal device. When the terminal device is registered in an in-network 2G network or an in-network 3G network, a voice call (including an emergency call) can be implemented in a CS domain.

[0066] It can be understood that the CS network adopts a circuit transmission mode and provides a circuit type data connection. The CS network can obtain relevant information of a mobile user (such as a number of the user, a location of the user, and information of services provided to the user) through a visit location register (VLR), analyzes and exchanges obtained call information (including a user number input on a mobile phone and some special network numbers), finds a called user, and connects circuits (transmission channels) of both parties (a calling user and a called user), so that the calling user and the called user can talk.

[0067] It should be noted that the network architecture shown in FIG. 3 is not limited to only including the devices and networks shown in the figure, and can also include other devices not represented in the figure, which will not be illustrated one by one in the present application.

[0068] Please refer to FIG. 4, which is a schematic diagram of a voice call scenario provided by the embodiments of the present application. As shown in FIG. 4, the terminal device 100 can perform voice data transmission with the terminal device 200 through the network device_1, the IMS network and the network device_2. The network device_1 is a network device corresponding to a cell in which the terminal device 100 currently resides, and the network device_2 is a network device corresponding to a cell in which the terminal device 200 currently resides. In some embodiments of the present application, the network device_1 and the network device_2 can be the same network device. In some embodiments of the present application, the terminal device 100 can be a party that initiates a voice call, that is, the terminal device 100 is a calling device, and the terminal device 200 is a called device. The terminal device 100 can request to perform a voice call with the terminal device 200. The terminal device 100 can be the terminal device in FIG. 3.

[0069] The embodiments of the present application do not particularly limit the specific structure of the execution subject of the method provided by the embodiments of the present application, as long as the execution subject can perform communication according to the method provided by the embodiments of the present application by running a program in which the code of the method provided by the embodiments of the present application is recorded. For example, the execution subject of the method provided by the embodiments of the present application can be a terminal device or a network device, or a functional module in the terminal device or the network device that can invoke and execute a program.

[0070] The technical solutions in the embodiments of the present application will be clearly and completely described in combination with the drawings in the embodiments of the present application. In the description of the embodiments of the present application, unless otherwise specified, “ / ” represents the meaning of or, for example, A / B can represent A or B; the “and / or” in the text only represents a description of the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which means that there are three cases of A alone, A and B together, and B alone. In addition, in the description of the embodiments of the present application, “multiple” means two or more than two.

[0071] It should be understood that the terms “first”, “second” and the like in the specification and claims of the present application and the drawings are used to distinguish different objects, and are not used to describe a specific order. In addition, the terms “include” and “have” and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but can optionally include steps or units not listed, or can optionally include other steps or units inherent to the process, method, product or device.

[0072] Reference to an "embodiment" in this application means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily mutually exclusive of one another. As will be apparent to those of ordinary skill in the art, embodiments described in this application can be combined with one another.

[0073] For the convenience of understanding, the emergency call method provided by the embodiments of the present application is specifically introduced below in combination with the drawings.

[0074] As shown in FIG. 5, the emergency call method provided by the embodiments of the present application is described by taking a terminal device UE as an example, and includes the following steps.

[0075] 501, the UE registers to the communication network of the home operator.

[0076] The home operator of the UE can refer to the operator to which the SIM card of the UE belongs. The communication network of the home operator of the UE can include a 4G network or a 5G network. The communication network of the home operator can include a core network. The core network of the home operator can also be referred to as a home core network.

[0077] 502, the UE receives the operation of the user dialing an emergency call number, and judges whether the home IMS network is successfully registered in the case that the home operator does not support IMS emergency call.

[0078] After the UE receives the operation of the user dialing an emergency call number, it can be judged whether the home operator supports IMS emergency call. It should be understood that in the case that the home operator supports IMS emergency call, the UE can regard the emergency call number (for example, 110, 112, etc.) dialed by the user as a true emergency call number. Then, the UE can initiate a call to the network through an IMS emergency call process.

[0079] It should be understood that in the case that the home operator does not support IMS emergency call, the UE can regard the emergency call number (for example, 110, 112, etc.) dialed by the user as a false emergency call number. Further, the UE judges whether the home IMS network (the IMS network of the home operator) is successfully registered. If the home IMS network (the IMS network of the home operator) is successfully registered, the UE initiates a call to the network through an IMS ordinary call process.

[0080] For example, as shown in (a) of FIG. 6, taking a mobile phone as an example, the mobile phone can display an interface 601, a user can input an emergency call number (for example, 120) through a dial pad 602 on the interface 601, and after the mobile phone receives an operation of the user inputting the emergency call number and clicking a dialing control 603, the mobile phone can display an interface 604 as shown in (b) of FIG. 6, the interface 604 can include emergency call information 605, for example, display "Emergency Center 120 is dialing…". And the mobile phone can determine whether the local IMS network is successfully registered.

[0081] In some embodiments, if the local IMS network is successfully registered, step 503 is performed.

[0082] For example, if the home operator of the UE is China Mobile, China Unicom or China Radio & TV, and the UE is successfully registered in the IMS network of China Mobile, China Unicom or China Radio & TV, when the UE receives a user input of a false emergency call number such as 120, the UE can directly initiate a call to the network in an IMS normal call process.

[0083] In some embodiments, if the local IMS network is not successfully registered, step 504 is performed.

[0084] For example, if the home operator of the UE is China Mobile or China Unicom, since China Mobile or China Unicom is equipped with a CS network, when the UE has a registration exception problem in the IMS network of China Mobile or China Unicom, after the UE receives an operation of a user dialing a false emergency call number such as 120, the UE can search for a local CS network in a case of supporting CS capability, and attempt to initiate a call on the local CS network.

[0085] In another embodiment, if the local IMS network is not successfully registered, step 507 is performed. That is, the UE searches for a communication network of a non-home operator supporting IMS emergency call in a case of satisfying a preset condition. The preset condition includes that the UE fails to register in the IMS network of the home operator.

[0086] For example, if the home operator of the UE is China Radio & TV, since China Radio & TV is not equipped with a CS network, when the UE has a registration exception problem in the IMS network of China Radio & TV, after the UE receives an operation of a user dialing a false emergency call number such as 120, the UE can directly search for a foreign network core network (for example, a core network of China Telecom), attempt IMS emergency registration and initiate an IMS emergency call on the foreign network core network.

[0087] 503. The UE initiates a call to the network in an IMS normal call process.

[0088] That is, in the case that the home operator does not support IMS emergency call, the UE regards the emergency call number (e.g. 110, 112, etc.) dialed by the user as a false emergency call number. Further, if the home IMS network (the IMS network of the home operator) is registered successfully, the UE initiates a call to the network in an IMS normal call procedure.

[0089] For example, the IMS normal call procedure is as follows:

[0090] The UE (the calling side) can send an INVITE message to the P-CSCF. When the P-CSCF receives the INVITE message, it sends a temporary response (100 Trying) message to the calling side, indicating that the P-CSCF has received the INVITE message. The P-CSCF sends a 183 Session Progress message to the calling side. After the calling side receives the 183 Session Progress, it sends a provisional response acknowledgement PRACK message in response. The calling side receives the 200 OK response sent by the called side. The calling side sends an Update message to update the media information. The called side responds to the Update message (i.e. sends a 200 OK response). The called side generates a ringing message (180 Ringing) and responds to the INVITE message (i.e. sends a 200 OK response). After the calling side receives the 200 OK response sent by the called side, it sends an acknowledgement ACK message in response, and thus the call session is established.

[0091] 504. Determine whether the UE supports CS capability.

[0092] The UE supporting CS capability means that the UE supports GU, and the UE not supporting CS capability means that the UE does not support GU. The GU includes GSM (i.e. 2G network) and UMTS (i.e. 3G network).

[0093] With the gradual withdrawal of CS networks, the UE itself also evaluates the removal of CS capability (i.e. does not support CS capability) based on cost considerations. When the CS network coverage decreases to a certain extent, the UE can no longer support CS capability, i.e. no longer support GU.

[0094] If the UE supports CS capability, step 505 can be performed. If the UE does not support CS capability, step 507 can be performed. That is, the UE searches for a communication network of a non-home operator supporting IMS emergency call in the case that the UE fails to register in the IMS network of the home operator and the UE does not support CS capability.

[0095] 505. Determine whether the UE searches for the CS network of the home network.

[0096] The CS network of the home network refers to the CS network supported by the home operator of the UE.

[0097] If the home operator of the UE supports the CS network, the UE can search for the CS network of the home network. For example, China Mobile, China Unicom and China Telecom support the CS network, and thus the UE whose home operator is China Mobile, China Unicom or China Telecom can search for the CS network.

[0098] If the home operator of the UE does not support the CS network, the UE cannot search for the CS network of the home network. For example, China Radio & Television does not support the CS network, and thus the UE whose home operator is China Radio & Television cannot search for the CS network.

[0099] If the UE searches for the CS network of the home network, step 506 can be performed. If the UE fails to search for the CS network of the home network, i.e., the UE fails to search for the CS network of the home network, step 507 can be performed. That is, the UE searches for the communication network of the non-home operator supporting the IMS emergency call under the condition that the UE fails to register with the IMS network of the home operator and the UE fails to search for the CS network of the home operator.

[0100] In addition, if the UE knows that the home network does not support the CS network, the UE does not need to search for the CS network of the home network, and can directly perform step 507.

[0101] It should be noted that step 504 and step 505 are optional. In addition, the present application does not limit the execution order of step 504 and step 505. In some embodiments, step 504 and step 505 can be performed after step 502, and in another embodiments, step 504 and step 505 can be performed after step 507.

[0102] 506. The UE registers with the CS network of the home network and initiates a call to the network in a CS ordinary call flow.

[0103] It should be understood that in step 502, the UE regards the emergency call number (e.g., 110, 112, etc.) dialed by the user as a false emergency call number in the case that the home operator does not support the IMS emergency call. If the UE fails to register with the IMS network of the home network, the UE can register with the CS network of the home network. After the UE registers with the CS network of the home network, the UE still regards the emergency call number dialed by the user as a false emergency call number (i.e., an ordinary call number) and initiates a call to the network in a CS ordinary call flow.

[0104] For example, the CS ordinary call flow is as follows:

[0105] The UE sends a call management (CM) service request (SERVICE REQUEST) message to the home network CS network, the home network CS network replies with an authentication request (AUTH REQUEST) message requiring authentication, and the UE replies with an authentication response (AUTH RESPONSE) message. The home network CS network initiates a security mode command (SECURITY MODE COMMAND) requiring integrity protection, and the UE replies with a security complete (SECURITY COMPLETE) message. The UE then sends a call setup (SETUP) message to the home network CS network, the home network CS network replies with a call proceeding (CALL PROCEEDING) message and sends an alerting (ALERTING) message, and the home network CS network replies with a connect (CONNECT) message after the call is answered, and the call enters a connected state.

[0106] In addition, in step 502, in the case that the home operator supports IMS emergency calls, the UE regards the emergency call number (e.g., 110, 112, etc.) dialed by the user as a true emergency call number. If the UE cannot initiate an emergency call in the IMS network, the UE can register with the home network CS network. After the UE registers with the home network CS network, the UE can still regard the emergency call number dialed by the user as a true emergency call number and initiate a call to the network through a CS emergency call procedure.

[0107] 507、UE performs inter-network search.

[0108] That is, the UE searches for a communication network of a non-home operator. The communication network of the non-home operator can include a 4G network or a 5G network.

[0109] 508、UE determines whether an inter-network network supporting IMS emergency calls is searched.

[0110] In some embodiments, the UE can determine whether the inter-network network supports IMS emergency calls through a system information block (SIB). The SIB message can be, for example, SIB1.

[0111] In some embodiments, if an IMS emergency call flag is present in the SIB message, the network in the cell can support IMS emergency calls of the UE. If the IMS emergency call flag is not present in the SIB message, the network in the cell does not support IMS emergency calls of the UE.

[0112] In other embodiments, the SIB message includes an IMS emergency call flag, and the IMS emergency call flag indicates whether the cell supports IMS emergency bearer services of the UE.

[0113] If the UE determines, according to the SIB of a cell, that the cell does not support the IMS emergency call of the UE, the cell can be ignored. If the UE determines, according to the SIB of a cell, that the cell supports the IMS emergency call of the UE, the UE can camp on the cell.

[0114] In some embodiments, the UE can be preset with a list of inter-network PLMNs, and the list of inter-network PLMNs can include PLMNs of inter-networks that support the IMS emergency call of the UE. The UE can perform cell search according to the preset list of inter-network PLMNs. If the UE searches for a cell that supports the IMS emergency call, the UE can camp on the cell.

[0115] If the UE searches for an inter-network that supports the IMS emergency call, step 509 can be performed. If the UE does not search for an inter-network that supports the IMS emergency call, step 510 can be performed.

[0116] 509. The UE initiates an IMS emergency call in the inter-network IMS network.

[0117] The UE can perform emergency registration in an inter-network core network (for example, a 4G core network or a 5G core network), perform emergency registration in an inter-network IMS network (a second IMS network), and then initiate an IMS emergency call.

[0118] 510. The UE fails in the current call.

[0119] If the UE does not search for an inter-network that supports the IMS emergency call, the UE cannot initiate an IMS emergency call, and eventually fails in the current call.

[0120] Based on the method provided in the embodiments of the present application, when a false emergency call cannot be successfully called in the home network, and there is an inter-network IMS network that supports a true emergency call in the same area, the UE can perform emergency registration in an inter-network core network, and then perform emergency registration in an inter-network IMS network and an emergency call process, thereby improving the success rate of emergency calls.

[0121] As shown in FIG. 7, the embodiments of the present application provide an emergency call method, taking a terminal device as a UE, and taking registration of the UE in a 4G network as an example for illustration, including the following steps:

[0122] 701. The UE registers with a 4G core network of a home operator.

[0123] The UE can send an attach request message (attach request) to the 4G core network of the home operator. For example, the UE can send the attach request to the MME of the 4G core network of the home operator.

[0124] The 4G core network receives the attach request message sent by the UE, and can send an attach accept message to the UE. Optionally, the 4G core network can authenticate the UE, and if the authentication is successful, the 4G core network can send the attach accept message to the UE. Then, the UE can send an attach complete message to the 4G core network. In this way, the UE is successfully attached (registered) to the 4G core network of the home operator. The UE displays a normal service state, and can perform data services.

[0125] 702a, the UE requests to register to the IMS network of the home network.

[0126] After the UE registers to the 4G core network of the home operator, the UE can register to the IMS network through the 4G access network.

[0127] For example, the UE can send a registration request to the IMS network of the home network. In the registration request, the contact header field does not carry an SOS field (emergency field).

[0128] 702b, the UE fails to successfully register to the IMS network of the home network.

[0129] In some cases, after the UE sends a registration request to the IMS network of the home network, the UE fails to receive a 200 OK response message from the IMS network of the home network, and thus the UE fails to successfully register to the IMS network of the home network, due to reasons of the UE itself or temporary reasons of the network.

[0130] For example, due to temporary abnormal state of the network, the IMS network can reply a 500 error code to the UE, and require the UE to retry after a time period indicated by a retry-after header field. In this case, the UE fails to successfully register to the IMS network of the home network.

[0131] 702c, the UE receives an operation of dialing an emergency call number by a user.

[0132] In some embodiments, after the UE receives the operation of dialing the emergency call number by the user, the UE can perform step 704a in the case that the UE fails to successfully register to the IMS network of the home network. That is, the UE searches for a communication network (i.e., a network of a different operator) of a non-home operator supporting IMS emergency calls in the case that a preset condition is met. The preset condition includes that the UE fails to register to the IMS network of the home network (the IMS network of the home network).

[0133] In some embodiments, after the UE receives the operation of dialing the emergency call number by the user, the UE can perform step 703 in the case that the UE fails to successfully register to the IMS network of the home network.

[0134] 703、UE judges whether the UE supports CS capability, and searches for a CS network of the network in the case that the UE supports CS capability.

[0135] For example, as shown in (a) of FIG. 6, in the case that the UE receives a user input of an emergency call number (a false emergency call number) and clicks the dialing control 603, the UE can search for a CS network of the network in the case that the UE fails to register to an IMS network of the network and the UE supports CS capability.

[0136] In the case that the UE successfully searches for a CS network of the network, the UE can initiate a call to the network in a CS normal call flow.

[0137] In the case that the UE does not support CS capability or the UE fails to search for a CS network of the network, step 704a can be performed. That is, the UE searches for a communication network (i.e., a network of a different operator) supporting IMS emergency call in the case that the UE fails to register to an IMS network of a home operator (an IMS network of the network) and the UE fails to search for a CS network of the network or the UE does not support CS capability.

[0138] 704a、The UE searches for a network of a different operator supporting IMS emergency call.

[0139] The related description can refer to step 508, and will not be repeated here.

[0140] In the case that the UE searches for a network of a different operator supporting IMS emergency call, step 704b can be performed; otherwise, the UE determines that the call fails.

[0141] 704b、The UE camps on a network of a different operator supporting IMS emergency call.

[0142] After the UE searches for a network of a different operator supporting IMS emergency call, the UE can camp on the network of the different operator.

[0143] 705、The UE initiates an emergency registration procedure to a core network of the different operator.

[0144] The UE can send an attach request to a core network of the different operator (a 4G core network of a home operator). In the case, a type of the attach request is emergency, i.e., a parameter carried by an EPS attach type information element of the attach request is emergency.

[0145] After receiving the attach request sent by the UE, the interworking core network can send an attach accept to the UE. After receiving the attach accept sent by the interworking core network, the UE can send an attach complete to the interworking core network. In this way, the UE completes the emergency registration of the interworking core network.

[0146] 706. The UE initiates an emergency PDN establishment to the interworking core network.

[0147] The UE sends a PDN connectivity request to the interworking core network (4G core network), carrying a type of emergency. After receiving the PDN connectivity request sent by the UE, the interworking core network can activate a bearer of an access point name (APN) type of SOS. Then, the UE replies to the interworking core network with a bearer activation acceptance message.

[0148] 707. The UE performs IMS network emergency registration.

[0149] After completing the emergency PDN establishment, the UE can send an IMS emergency registration request (sip register) to the interworking IMS network. The sip register includes a contact header field, which carries an SOS field (emergency field). After receiving the sip register sent by the UE, the interworking IMS network can reply to the UE with a 200 OK response message to complete the IMS emergency registration.

[0150] Optionally, the interworking IMS network can authenticate the UE. For example, the interworking IMS network can send a 401 (unauthorized code) to the UE. After receiving the 401, the UE can send a sip register message to the interworking IMS network and carry the authentication content. After the authentication is passed, the interworking IMS network can reply to the UE with a 200 OK response message to complete the IMS emergency registration.

[0151] 708. The UE initiates an emergency call in the interworking IMS network.

[0152] The UE can send an INVITE message to the interworking IMS network. The INVITE message includes a to header field, which includes an emergency identifier corresponding to an emergency number. At this point, the emergency call is officially initiated.

[0153] For example, if the emergency number is 122, the emergency identifier can be urn:service:sos.marine; if the emergency number is 110, the emergency identifier can be urn:service:sos.police.

[0154] Based on the method provided in the embodiments of the present application, if the UE fails to register to the IMS network of the home network, the UE can search the CS network of the home network after receiving the operation of the user dialing the emergency call number, and in the case that the search of the CS network of the home network is successful, the UE can initiate a call to the network in a CS ordinary call process; in the case that the UE does not support CS capability or the UE fails to search the CS network of the home network, the UE can search a foreign network supporting IMS emergency call, and initiate an emergency registration process and an emergency PDN establishment to the core network of the foreign network, and then the UE performs IMS network emergency registration and initiates an emergency call in the IMS network of the foreign network, thereby improving the success rate of the emergency call.

[0155] As shown in FIG. 8, the embodiments of the present application provide an emergency call method, taking a terminal device as UE, and taking the UE registering in a 5G network as an example for illustration, which comprises the following steps:

[0156] 801. The UE registers to the 5G core network of the home operator.

[0157] The UE can send a registration request message (Registration Request) to the 5G core network of the home operator. For example, the UE can send the Registration Request to the AMF of the 5G core network of the home operator. After receiving the Registration Request sent by the UE, the AMF can send a registration acceptance message (Registration Accept) to the UE. Then, the UE can send a registration completion message (Registration complete) to the AMF. In this way, the UE successfully registers to the 5G core network of the home operator. The UE displays a normal service state and can perform data service.

[0158] 802a. The UE requests to register to the IMS network of the home network.

[0159] After the UE registers to the 5G core network of the home operator, the UE can register to the IMS network through the 5G access network.

[0160] For example, the UE can send a registration request to the IMS network of the home network. The contact header field of the registration request does not carry an SOS field (emergency field).

[0161] 802b. The UE fails to successfully register to the IMS network of the home network.

[0162] In case that the UE fails to register to the home IMS network, i.e. after step 802b, step 803 or 804a can be performed.

[0163] In some embodiments, in case that the UE registers to the 5G core network, if the UE fails to register to the home IMS network, the UE can fall back to the 4G network to re-register to the home IMS network. That is, the embodiments of the present application can further comprise steps 802c-802e.

[0164] 802c, the UE falls back to the 4G network.

[0165] The UE can fall back to the 4G core network of the home operator.

[0166] 802d, the UE requests to register to the home IMS network.

[0167] 802e, the UE fails to register to the home IMS network.

[0168] 802f, the UE receives an operation of dialing an emergency call number by a user.

[0169] In case that the UE fails to register to the home IMS network after falling back to the 4G network, after the UE receives the operation of dialing the emergency call number by the user, step 803 or 804a can be performed.

[0170] 803, the UE determines whether the UE itself supports CS capability, and searches for a home CS network in case that the UE supports the CS capability.

[0171] In case that the UE supports the CS capability and succeeds in searching for the home CS network, the UE can initiate a call to the network in a CS normal call flow. In case that the UE does not support the CS capability or fails to search for the home CS network, step 804a can be performed.

[0172] 804a, the UE searches for a foreign network supporting IMS emergency call.

[0173] The related description can refer to step 508, which is not repeated here.

[0174] In case that the UE searches for the foreign network supporting the IMS emergency call, step 804b can be performed; otherwise, the UE determines that the call fails.

[0175] 804b, the UE camps on the foreign access network supporting the IMS emergency call.

[0176] 805, the UE initiates an emergency registration procedure to the foreign core network.

[0177] The UE can send a registration request message (Registration Request) to the foreign network core network (5G core network of a non-home operator) with a type of emergency. For example, the UE can send the Registration Request to an AMF of the foreign network core network. After receiving the Registration Request sent by the UE, the AMF can send a registration acceptance message (Registration Accept) to the UE. Then, the UE can send a registration completion message (Registration complete) to the AMF. In this way, the UE is successfully registered to the foreign network core network.

[0178] 806. The UE initiates an emergency PDU establishment to the foreign network core network.

[0179] The UE can send a PDU session establishment request (PDU Session Establishement request) to the foreign network core network with a type of emergency. After receiving the PDU Session Establishement request sent by the UE, the foreign network core network can send a PDU session establishment acceptance message (PDU Session Establishement Accept), so as to establish an SOS (emergency) PDU session. After completing the emergency PDU establishment, the UE can perform step 807.

[0180] 807. The UE performs IMS network emergency registration.

[0181] For related descriptions, reference can be made to step 707, which will not be repeated here.

[0182] 808. The UE initiates an emergency call in the foreign network IMS network.

[0183] For related descriptions, reference can be made to step 708, which will not be repeated here.

[0184] Based on the method provided in the embodiments of the present application, if the UE fails to successfully register to the home network IMS network, after the UE receives the operation of the user dialing an emergency call number, the UE can first search for the home network CS network. If the search for the home network CS network is successful, the UE can initiate a call to the network in a CS ordinary call process. If the UE does not support CS capability or the search for the home network CS network fails, the UE can search for a foreign network supporting IMS emergency call, and initiate an emergency registration process and an emergency PDU establishment to the foreign network core network. Then, the UE performs IMS network emergency registration, and initiates an emergency call in the foreign network IMS network, thereby improving the success rate of the emergency call.

[0185] A hardware structure of a terminal device is shown in FIG. 9, which can include a processor, an external memory interface, an internal memory, a Universal Serial Bus (USB) interface, a charging management module, a power management module, a battery, an antenna 1, an antenna 2, a mobile communication module, a wireless communication module, an audio module, a sensor module, a key, a motor, an indicator, a camera, a display screen, and a SIM card slot, etc. The audio module can include a speaker, a receiver, a microphone, an earphone interface, etc., and the sensor module can include a pressure sensor, a gyroscope sensor, a barometric pressure sensor, a magnetic sensor, an acceleration sensor, a distance sensor, a proximity light sensor, a fingerprint sensor, a temperature sensor, a touch sensor, an ambient light sensor, a bone conduction sensor, etc.

[0186] It can be understood that the structure shown in the embodiments of the present application does not constitute a specific limitation on the terminal device. In other embodiments, the terminal device can include more or fewer components than shown, or combine certain components, or split certain components, or different component arrangements. The components shown can be implemented in hardware, software, or a combination of software and hardware.

[0187] The processor can include one or more processing units, for example: the processor can include an Application Processor (AP), a Modem (also known as a baseband processor), a Graphics Processing Unit (GPU), an Image Signal Processor (ISP), a controller, a video codec, a Digital Signal Processor (DSP), and / or a Neural-network Processing Unit (NPU), etc. Different processing units can be independent devices or integrated into one or more processors. The processor is the nerve center and command center of the terminal device, and the controller can generate operation control signals according to instruction operation codes and timing signals to complete the control of fetching and executing instructions.

[0188] The wireless communication function of the terminal device can be realized by the antenna 1, the antenna 2, the mobile communication module, the wireless communication module, and the Modem, etc. In some embodiments, the antenna 1 and the mobile communication module of the terminal device are coupled, and the antenna 2 and the wireless communication module are coupled, so that the terminal device can communicate with the network side device and other terminal devices through wireless communication technology.

[0189] In addition, an operating system runs on top of the above components. For example, iOS operating system, Android open source operating system, Windows operating system, etc.

[0190] The operating system of the terminal device can adopt a layered architecture, an event-driven architecture, a microkernel architecture, a microservice architecture, or a cloud architecture. Embodiments of the present application take an Android system with a layered architecture as an example to exemplarily illustrate the software and hardware structure of the terminal device. It should be noted that, although the embodiments of the present application take the Android system as an example for illustration, the basic principles are also applicable to terminal devices based on iOS or Windows operating systems.

[0191] FIG. 10 is a schematic diagram of the software structure of the terminal device. The software structure adopts a layered architecture, which divides the software into several layers, each layer having a clear role and division of labor. The layers communicate with each other through software interfaces. Taking the Android system as an example, the Android system runs on the AP, and in some embodiments, the Android system is divided into five layers, from top to bottom, the application layer, the application framework layer (Framework), the Android runtime and system library, the hardware abstraction layer (HAL), and the system kernel layer (Kernel).

[0192] The application layer can include a series of application packages. The application packages can include camera, gallery, calendar, call, map, WLAN, Bluetooth, music, video, short message, etc. APPs, and the application layer can also include systemUI (system UI), which is used to display the interface of the terminal device, such as displaying the signal icon corresponding to the SIM card, displaying the call interface, etc. The application framework layer provides application programming interfaces (APIs) and programming frameworks for the applications of the application layer. The application framework layer includes some pre-defined functions. For example, the application framework layer can include a window manager, a content provider, a view system, a phone manager, a resource manager, a notification manager, etc. The phone manager (telephony) is used to provide the call function of the terminal device, such as the management of the call state (including call connection, call hang-up, etc.). The application framework layer can also include a radio interface layer (RIL), and the Modem can interact with the telephony through the RIL.

[0193] The modem can include a non-access stratum (NAS) layer, a radio resource control (RRC) layer, a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, a medium access control (MAC) layer, and a physical (PHY) layer. Each of the foregoing layers can be a software module. The modem can interact with a base station through an antenna.

[0194] In addition, some embodiments of the present application provide a terminal device, comprising: one or more processors and a memory; the memory is configured to store computer program codes, the computer program codes comprising computer instructions, when the one or more processors execute the computer instructions, the terminal device performs the following random access method.

[0195] Some embodiments of the present application provide a chip system applied to a terminal device, the chip system comprising at least one processor and an interface, the interface being configured to receive instructions and transmit the instructions to the at least one processor; the at least one processor executes the instructions to make the terminal device perform the following random access method. The chip system can be a modem or a system on chip (Soc) comprising a modem, and the above method can be implemented by a modem.

[0196] The method of some embodiments of the present application can be implemented by a modem of a terminal device.

[0197] For example, after the terminal device receives the operation of the user dialing an emergency number, the modem can search for a communication network of a non-home operator supporting IMS emergency call under the condition of meeting a preset condition; the preset condition comprises that the terminal device fails to register in an IMS network of a home operator; in the case of searching for a communication network of a non-home operator supporting IMS emergency call, the terminal device can be registered in an IMS network of the non-home operator in emergency, send an invitation (INVITE) message to the IMS network of the non-home operator, and the INVITE message comprises an emergency identifier corresponding to the emergency number.

[0198] The embodiment of the present application further provides a chip system, as shown in Fig. 11, which comprises at least one processor 1101 and at least one interface 1102. The processor 1101 (which can be a Modem) and the interface 1102 can be interconnected through a line. For example, the interface 1102 can be used to receive signals from other devices (for example, the memory of a terminal device). For another example, the interface 1102 can be used to send signals to other devices (for example, the processor 1101).

[0199] For example, the interface 1102 can read instructions stored in the memory of the terminal device and send the instructions to the processor 1101. When the instructions are executed by the processor 1101, the terminal device (such as the terminal device shown in Fig. 9) can perform various steps in the above embodiment.

[0200] Of course, the chip system can also contain other discrete devices, which are not limited in the embodiment of the present application.

[0201] The embodiment of the present application further provides a computer readable storage medium, which comprises computer instructions, when the computer instructions are run on a terminal device (such as the terminal device shown in Fig. 9), the terminal device performs various functions or steps performed by the terminal device (for example, UE) in the above method embodiment.

[0202] The embodiment of the present application further provides a computer program product, when the computer program product is run on a computer, the computer performs various functions or steps performed by the terminal device in the above method embodiment.

[0203] The embodiment of the present application further provides a processing device, which can be divided into different logical units or modules according to functions, each unit or module performs different functions, so that the processing device performs various functions or steps performed by the terminal device in the above method embodiment.

[0204] Through the above description of the embodiment, those skilled in the art can clearly understand that the above functions can be completed by different functional modules according to needs, that is, the internal structure of the device is divided into different functional modules to complete all or part of the above described functions.

[0205] In several embodiments provided in the present application, it should be understood that the disclosed apparatus and method can be implemented by other manners. For example, the apparatus embodiments described above are merely illustrative, for example, the division of the modules or units is merely a logical function division, and actual implementation can have another division manner, for example, a plurality of units or components can be combined or integrated into another apparatus, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the units or components shown or discussed can be indirect coupling or communication connection through some interfaces, apparatuses or units, and can be electrical, mechanical or other forms.

[0206] The units described as separate components can or can not be physically separate, and the components shown as units can be one physical unit or a plurality of physical units, that is, can be located in one place, or can be distributed to a plurality of different places. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiment scheme.

[0207] In addition, the functional units in each embodiment of the present application can be integrated in one processing unit, or each unit can be physically present separately, or two or more units can be integrated in one unit. The integrated unit can be realized in the form of hardware or in the form of a software functional unit.

[0208] The integrated unit, if realized in the form of a software functional unit and sold or used as an independent product, can be stored in a readable storage medium. Based on this understanding, the technical solutions of the embodiments of the present application essentially or the part of the prior art that contributes to the technical solutions or all or part of the technical solutions can be embodied in the form of a software product, which is stored in a storage medium and includes a plurality of instructions for causing an apparatus (which can be a single-chip microcomputer, a chip, etc.) or a processor to execute all or part of the steps of the method described in the embodiments of the present application. The foregoing storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and various storage medium that can store program codes.

[0209] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto, any change or replacement within the technical scope disclosed in the present application should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. An emergency call method, characterized in that: Applied to a terminal device, the terminal device being registered on a communication network of a home operator, the method comprising: Receiving an operation to dial an emergency number, searching for a communication network of a non-home operator that supports IMS emergency calls if a preset condition is met; the preset condition includes that the terminal device fails to register on the IMS network of the home operator; When a communication network of a non-home operator supporting IMS emergency calls is searched, the terminal device urgently registers with the IMS network of the non-home operator and sends an INVITE message to the IMS network of the non-home operator, where the INVITE message includes an emergency identifier corresponding to the emergency number.

2. The method according to claim 1, characterized in that The preset conditions also include: The terminal device fails to search for the circuit switched CS network of the home operator or the terminal device does not support CS capability.

3. The method according to claim 1 or 2, characterized in that The searching for a communication network of a non-home operator supporting IMS emergency calls includes: The terminal device receives a system information block SIB of the cell of the non-home operator; The terminal device determines whether the cell of the non-home operator supports IMS emergency calls according to the SIB.

4. The method according to claim 1 or 2, characterized in that The terminal device presets a public land mobile network PLMN list, the PLMN list includes PLMNs that support IMS emergency calls, and the searching for a communication network of a non-home operator that supports IMS emergency calls includes: The terminal device searches for cells according to the PLMN list.

5. The method according to any one of claims 1 to 4, characterized in that Before the terminal device urgently registers with the second IMS network of the non-home operator, the method further includes: Emergency registration of the terminal device to the communication network of the non-home operator; The terminal device establishes an emergency packet data network PDN connection or an emergency protocol data unit PDU connection with the communication network of the non-home operator.

6. The method according to claim 5, characterized in that The terminal device urgently registers with the second IMS network of the non-home operator, including: The terminal device sends an emergency registration request to the second IMS network, where the emergency registration request includes an emergency field; The terminal device receives a 200 OK response message from the second IMS network.

7. The method according to any one of claims 1 to 6, characterized in that The terminal device fails to register on the IMS network of the home operator including: When the terminal device is registered on the 4G network of the home operator, registration on the IMS network of the home operator fails; or When the terminal device is registered on the 5G network of the home operator, registration on the IMS network fails; and after the terminal device switches from the 5G network of the home operator to the 4G network of the home operator, registration on the IMS network of the home operator fails.

8. A terminal device, characterized in that: The terminal device includes: a memory and one or more processors; the memory is coupled to the processor; The memory is used to store computer program code, and the computer program code includes computer instructions; when the computer instructions are executed by the processor, the terminal device executes the method according to any one of claims 1 to 7.

9. A computer-readable storage medium, characterized in that including computer instructions; When the computer instructions are executed on a terminal device, the terminal device is caused to execute the method according to any one of claims 1 to 7.

10. A chip system, characterized in that: The chip system includes one or more interfaces and one or more processors; The chip system is applied to a terminal device; the interface is used to receive a signal from the memory of the terminal device and send the signal to the processor, the signal including computer instructions stored in the memory; when the processor executes the computer instructions, the terminal device executes the method as described in any one of claims 1-7.

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