Network selection method and apparatus, terminal, network device, medium, and program product
Through the collaborative mechanism between user equipment and PLMN, the problem of increased 4G network load during 5G network failures has been solved, enabling the rational allocation of network resources and efficient communication of user equipment in complex environments.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- CHINA TELECOM CORP LTD TECHNOLOGY INNOVATION CENTER
- Filing Date
- 2025-11-25
- Publication Date
- 2026-07-02
Smart Images
Figure CN2025137562_02072026_PF_FP_ABST
Abstract
Description
Network selection methods, devices, terminals, network equipment, media and software products
[0001] Related applications
[0002] This application claims priority to Chinese patent application filed on December 26, 2024, with application number 202411943870.2, entitled "Network Selection Method, Apparatus, Terminal, Network Equipment, Media and Program Product", the entire contents of which are incorporated herein by reference. Technical Field
[0003] This disclosure relates to the field of wireless communication technology, and in particular to a network selection method, a network selection device, a network equipment, a terminal, a computer-readable storage medium, and a computer program product. Background Technology
[0004] Inter-network roaming allows user equipment (UE) to leave its home network (the network of the operator to which the user has signed up) and access the 5G network of a third-party operator to obtain communication services. In other words, the UE can obtain 5G inter-network roaming services from the third operator. For the third operator providing roaming services, its 4G network is not a "forbidden PLMN (Public Land Mobile Network)" for the UE. When the 5G network fails, the UE will always prioritize the 4G network of the third operator when reselecting the PLMN, which will increase the load on the 4G network.
[0005] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention
[0006] This disclosure provides a network selection method, configuration apparatus, network device, storage medium, and computer program product that at least partially overcomes the problem of increased load on 4G networks caused by disaster roaming attachment in related technologies.
[0007] Other features and advantages of this disclosure will become apparent from the following detailed description, or may be learned in part from practice of this disclosure.
[0008] According to a first aspect of this disclosure, a network selection method is provided, applied to a terminal, comprising: sending a disaster roaming attach request to a first public terrestrial mobile network (PLMN); receiving an attach rejection message from the first PLMN, without considering the first PLMN.
[0009] In one or more embodiments of this disclosure, sending a disaster roaming attach request to a first PLMN includes: sending the disaster roaming attach request to a 4G network belonging to the first PLMN, wherein a 5G network belonging to the first PLMN has entered a fault state.
[0010] In one or more embodiments of this disclosure, the attach denial message carries an Evolved Packet System Mobility Management (EMM) cause value, which indicates that the 4G network of the first PLMN is temporarily not allowing disaster roaming.
[0011] In one or more embodiments of this disclosure, the attach rejection message carries a timer, and the network selection method further includes: in response to the attach rejection message, starting the timer, wherein the timer is used to time the terminal to wait for a set time before considering the first PLMN during network selection.
[0012] In one or more embodiments of this disclosure, the set time is configured by the terminal based on detected network condition parameters, or the set time is a time parameter pre-existing in the terminal, or the set time is configured based on the value of the timer, and the attach rejection message carries the value of the timer.
[0013] In one or more embodiments of this disclosure, the network selection method further includes: detecting that the timer has reached the set time, sending the disaster roaming attach request to the 4G network of the first PLMN; receiving access permission information fed back by the 4G network based on the disaster roaming attach request, and accessing the 4G network.
[0014] In one or more embodiments of this disclosure, the terminal further includes: detecting that the timer has reached a set time, and if the terminal has already connected to the second PLMN, no longer sending the disaster roaming attach request.
[0015] In one or more embodiments of this disclosure, after receiving the attach rejection message from the first PLMN, the network selection method further includes: sending a disaster roaming registration request to the second PLMN.
[0016] In one or more embodiments of this disclosure, after sending a disaster roaming registration request to the second PLMN, the network selection method further includes: receiving registration acceptance information from the second PLMN based on the disaster roaming registration request; or receiving registration rejection information from the second PLMN based on the disaster roaming registration request.
[0017] In one or more embodiments of this disclosure, sending a disaster roaming registration request to a second PLMN includes: sending the disaster roaming registration request to a 5G network belonging to the second PLMN.
[0018] In one or more embodiments of this disclosure, the first PLMN is the visited network of the terminal, and the identifier of the second PLMN belongs to the prohibited access identifier list of the terminal.
[0019] According to a second aspect of this disclosure, a network selection method is provided, applied to a first PLMN, comprising: in response to a disaster roaming attach request from a terminal to be accessed, sending an attach rejection message to the terminal to be accessed, indicating that the first PLMN temporarily does not allow disaster roaming.
[0020] In one or more embodiments of this disclosure, in response to a disaster roaming attach request from a terminal to be accessed, sending an attach rejection message to the terminal to be accessed includes: in response to the disaster roaming attach request, detecting whether the number of disaster roaming terminals already connected to the first PLMN has reached a preset access number; and if the preset access number has been reached, sending the attach rejection message to the terminal to be accessed.
[0021] In one or more embodiments of this disclosure, instructing a first PLMN to temporarily disallow disaster roaming includes: instructing the 4G network of the first PLMN to temporarily disallow the disaster roaming.
[0022] In one or more embodiments of this disclosure, the preset access number is the maximum number of disaster roaming accesses configured in the Mobility Management Entity (MME).
[0023] In one or more embodiments of this disclosure, the MME carries an EMM cause value in the attach denial message, the EMM cause value being used to indicate that the 4G network of the first PLMN temporarily does not allow the disaster roaming.
[0024] In one or more embodiments of this disclosure, the EMM cause value is based on a reused existing parameter configuration of the MME, or the EMM cause value is based on a newly added parameter configuration of the MME.
[0025] In one or more embodiments of this disclosure, the attach rejection message carries a timer, which is used to time the timer when the terminal to be accessed considers the first PLMN during network selection after waiting for a set time.
[0026] In one or more embodiments of this disclosure, the attach rejection message also carries the value of the timer, the value of which is used to determine the set time.
[0027] According to a third aspect of this disclosure, a network selection method is provided, applied to a second PLMN, comprising: receiving a disaster roaming registration request from a terminal to be connected; and sending registration acceptance information or registration rejection information to the terminal to be connected based on the disaster roaming registration request.
[0028] In one or more embodiments of this disclosure, the disaster roaming registration request includes a disaster roaming identifier, and sending acceptance registration information or rejection registration information to the terminal to be accessed based on the disaster roaming registration request includes: sending the acceptance registration information or the rejection registration information to the terminal to be accessed based on the identification result of the disaster roaming identifier.
[0029] According to a fourth aspect of this disclosure, a network selection apparatus is provided, comprising: a first transmitting module for transmitting a disaster roaming attach request to a first public terrestrial mobile network (PLMN); and a first receiving module for receiving an attach rejection message from the first PLMN, without considering the first PLMN.
[0030] According to a fifth aspect of this disclosure, a network selection apparatus is provided, comprising: a second sending module, configured to send an attach rejection message to a terminal to be accessed in response to a disaster roaming attach request from a terminal to be accessed, indicating that a first PLMN temporarily does not allow disaster roaming.
[0031] According to a sixth aspect of this disclosure, a network selection apparatus is provided, comprising: a second receiving module for receiving a disaster roaming registration request from a terminal to be accessed; and a third sending module for sending registration acceptance information or registration rejection information to the terminal to be accessed based on the disaster roaming registration request.
[0032] According to a seventh aspect of this disclosure, a terminal is provided, comprising: a processor; and a memory for storing executable instructions of the processor; the processor being configured to perform the network selection method of the first aspect described above by executing the executable instructions.
[0033] According to an eighth aspect of this disclosure, a network device is provided, comprising: a processor; and a memory for storing executable instructions of the processor; the processor being configured to perform the network selection method of the second or third aspect described above by executing the executable instructions.
[0034] According to a ninth aspect of this disclosure, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, causes the processor to perform the network selection method of the first, second, or third aspect described above.
[0035] According to a tenth aspect of this disclosure, a computer program product is provided, on which a computer program is stored, which, when executed by a processor, causes the processor to perform the network selection method of the first, second, or third aspect described above.
[0036] The network selection scheme provided in the embodiments of this disclosure allows the UE to actively search for a first PLMN that can provide disaster roaming services by sending a disaster roaming attach request. When the first PLMN is working normally, it rejects the UE's access request or service request based on the feedback attach rejection message, and instructs the UE not to consider this network when making network selection for a period of time, so as to prevent the UE from accessing the network that increases the pressure on network resources, thereby reducing the load on the network providing disaster roaming services. At the same time, it enables the UE to promptly exclude networks that are clearly unaccessible, and thus explore other potential available networks more efficiently.
[0037] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description
[0038] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure. It is obvious that the drawings described below are merely illustrative of some embodiments of this disclosure, and those skilled in the art can derive other drawings from these drawings without any inventive effort.
[0039] Figure 1 shows a schematic diagram of a network selection system according to an embodiment of the present disclosure;
[0040] Figure 2 shows a flowchart of a network selection method according to an embodiment of the present disclosure;
[0041] Figure 3 shows a flowchart of another network selection method in an embodiment of this disclosure;
[0042] Figure 4 shows a flowchart of another network selection method according to an embodiment of the present disclosure;
[0043] Figure 5 shows a flowchart of another network selection method in an embodiment of this disclosure;
[0044] Figure 6 shows a schematic diagram of a network selection device according to an embodiment of the present disclosure;
[0045] Figure 7 shows a schematic diagram of another network selection device in an embodiment of this disclosure;
[0046] Figure 8 shows a schematic diagram of another network selection device according to an embodiment of the present disclosure;
[0047] Figure 9 shows a structural block diagram of an electronic device according to an embodiment of the present disclosure. Detailed Implementation
[0048] Example embodiments of this disclosure will be described more fully below with reference to the accompanying drawings. These embodiments are provided to make this disclosure more comprehensive and complete, and to fully convey the concept of this disclosure to those skilled in the art through example embodiments. However, example embodiments can be implemented in many forms, and this disclosure should not be construed as limited to the examples set forth herein. The described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments.
[0049] Furthermore, the accompanying drawings are merely illustrative of this disclosure and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions of them will be omitted. Some block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically independent entities. These functional entities may be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices.
[0050] In this article, the two terms connected by "and / or" can be either one of them existing alone, or both existing simultaneously. That is, A and / or B can mean: A exists alone, B exists alone, or A and B exist simultaneously.
[0051] In some cases, for the sake of brevity and / or to aid in understanding the scope of this disclosure, a single embodiment may combine multiple features. It should be understood that in such cases, these multiple features may be provided individually (e.g., in different embodiments) or in any other suitable combination. Conversely, when different features are described in different embodiments, these different features may be combined to form a single embodiment unless otherwise stated or implied. This principle also applies to the claims, whose claims may be rearranged in any combination, i.e., any claim may be modified to include any feature defined in the other claims.
[0052] 5G inter-network roaming refers to the ability of a terminal device (also referred to as a user equipment, UE, terminal, or user terminal) to automatically switch to and access the 5G network of another operator when the 5G network coverage of its operator is insufficient, according to roaming agreements or relevant regulations between operators. Under normal circumstances, the terminal device can only obtain 5G inter-network roaming services and cannot obtain 4G inter-network roaming services, meaning it is restricted from accessing the 4G network. However, when the 5G network being accessed fails and can no longer provide services, the terminal device is allowed to temporarily access the 4G network for 4G disaster roaming to obtain basic communication services.
[0053] In addition, there are other operators' 5G networks that are normally forbidden public land mobile networks (PLMNs) for UEs to access. However, in disaster areas, UEs can bypass the forbidden list to select these normally forbidden 5G PLMNs for disaster roaming.
[0054] As shown in Figure 1, under normal circumstances, UE102 can perform 5G inter-network roaming, and the roaming operator's 4G network is not a prohibited PLMN for UE. However, when the roaming operator's 5G network fails, the UE will reselect the PLMN. At this time, since the 4G network of the same operator has a higher priority, UE1012 sends an attach request signaling to the roaming operator's 4G base station 104 through the radio interface to request access to the 4G network. The attach request signaling contains the UE's identification information, capability information, and attach type. After receiving the UE's attach request, the 4G base station performs preliminary processing on the attach request signaling and then forwards the attach request signaling to the Mobility Management Entity (MME) 106 through the S1-MME interface.
[0055] Other 5G networks that are on the prohibited access list but can still provide disaster roaming services have relatively low priority. This causes the UE to always prioritize the roaming operator's 4G network and not be able to select other 5G networks. In other words, it cannot send a disaster roaming registration request to AMF110 through 5G base station 108, which increases the load on the 4G network.
[0056] Based on the network selection scheme disclosed herein, the UE actively seeks a first PLMN that can provide disaster roaming services by sending a disaster roaming attach request. When the first PLMN is working normally, it rejects the UE's access request or service request based on the feedback attach rejection message, and instructs the UE not to consider this network when making network selection for a period of time, so as to prevent the UE from accessing the network, avoid increasing the pressure on network resources, thereby reducing the load on the network providing disaster roaming services, and at the same time enabling the UE to promptly exclude networks that are clearly unaccessible, so as to explore other potential available networks more efficiently.
[0057] To facilitate understanding, the following is an explanation of several terms used in this disclosure.
[0058] Public Land Mobile Network (PLMN): refers to a network established and operated for the purpose of providing land mobile communication services to the public.
[0059] Mobility Management Entity (MME): A key control node in the Long-Term Evolution (LTE, 4G network technologies) core network, primarily responsible for mobility management and session management related functions.
[0060] Access and Mobility Management Function (AMF): This is an important functional unit in the 5G core network (5GC), mainly responsible for access and mobility management functions, similar to the MME in 4G, but with expanded and optimized functions and architecture.
[0061] Radio Access Technology (RAT): refers to the wireless communication technology that connects the UE to the core network.
[0062] Evolved Packet System Mobility Management (EMM) is a key function in the LTE network and Evolved Packet System (EPS) architecture. It is mainly responsible for managing user equipment (UE) mobility-related transactions in the network, including UE attach, detach, location update, and tracking area update operations.
[0063] Disaster roaming refers to the situation in disaster areas where the network of the UE's home operator may be partially or completely paralyzed due to the disaster, and normal communication services cannot be guaranteed. In this case, the UE is allowed to access the network of a non-home operator to obtain basic communication services. For example, when PLMN-1 fails and cannot provide network services, the UE is allowed to roam to PLMN-2. PLMN-2 refers to the network that the UE is not allowed to access under normal circumstances.
[0064] Inter-network roaming: refers to the ability of a UE to roam to other PLMNs for a given PLMN to obtain communication services. The UE's given PLMN (home network) and other PLMNs (visited networks) are located in the same country, but usually belong to different operators. In addition, inter-network roaming services can be activated only for 5G, that is, the UE can only obtain 5G inter-network roaming services, but cannot roam to 4G.
[0065] The following will describe in more detail the various steps of the network selection method provided in this disclosure, with reference to the accompanying drawings and embodiments.
[0066] Figure 2 shows a flowchart of a network selection method according to an embodiment of the present disclosure.
[0067] As shown in Figure 2, the network selection method according to an embodiment of the present disclosure is applied to a terminal and includes steps S202 to S204.
[0068] Step S202: Send a disaster roaming attach request to the first public terrestrial mobile network (PLMN).
[0069] The first PLMN refers to the non-home network of the terminal UE, which geographically covers the disaster area where the UE is currently located. The first PLMN can be determined based on factors such as signal strength and network priority.
[0070] Disaster roaming attach request refers to a request issued by a UE in a disaster scenario. When the network service currently accessed by the terminal is restricted or unavailable, the UE will send this request in order to obtain communication services, hoping to attach (access and establish a connection) to another network (such as the first PLMN) for communication. The network currently accessed by the terminal can be the terminal's local home network or a non-home network.
[0071] In some embodiments, a disaster roaming attach request may include the UE’s identification information and a specific identifier or parameter indicating that the request is a disaster roaming attach request, enabling the first PLMN to distinguish between a normal roaming request and an emergency request in a disaster scenario.
[0072] Step S204: Receive the attachment rejection message from the first PLMN, without considering the first PLMN.
[0073] The attach rejection message can be sent to the UE after the first PLMN receives the UE's disaster roaming attach request, when the first PLMN evaluates its own network status, resource availability, roaming policy, etc. If the network load is too high or there is no suitable roaming protocol or security policy restriction with the UE's home network, the disaster roaming attach request cannot be met.
[0074] In some embodiments, the attached rejection message may include code indicating a reason for rejection.
[0075] In some embodiments, not considering the first PLMN during network selection means that the user equipment (UE) should not consider the combination of the public land mobile network (i.e., the first PLMN) that provides this rejection reason (i.e., the attach rejection message) with the radio access technology (RAT) as a candidate for public land mobile network selection.
[0076] In this embodiment, the UE actively seeks a first PLMN that can provide disaster roaming services by sending a disaster roaming attach request. When the first PLMN is working normally, it sends an attach rejection message to the UE, rejecting the UE's access request or service request, and instructing the UE not to consider the first PLMN when making network selection for a period of time, so as to prevent the UE from accessing the network, avoid increasing the pressure on its network resources, thereby reducing the load on the network providing disaster roaming services, and enabling the UE to promptly exclude networks that are clearly unaccessible, so as to explore other potential available networks more efficiently.
[0077] In embodiments of this disclosure, sending a disaster roaming attach request to a first PLMN includes: the 5G network belonging to the first PLMN entering a fault state, and sending a disaster roaming attach request to the 4G network belonging to the first PLMN.
[0078] In some embodiments, under normal circumstances, the UE uses the 5G service of the inter-network roaming area by accessing the visited 5G network (5G of PLMN-1). In addition, even if the UE is in an area where it can access the visited operator's network (PLMN-1), and this visited operator has both 4G and 5G networks, the UE is prohibited from accessing its 4G network (4G of PLMN-1) due to the RAT restriction in the user's subscription information. However, if the visited 5G network (5G of PLMN-1) fails, the UE is allowed to access the 4G network (4G of PLMN-1) to achieve disaster roaming. At this time, the UE sends a disaster roaming attach request to the 4G network belonging to the first PLMN to apply for access to the 4G network (4G of PLMN-1) to achieve disaster roaming.
[0079] In these embodiments, in the case of inter-network roaming, if the visited 5G network (5G of PLMN-1) fails, a disaster roaming attach request is sent to the 4G network (4G of PLMN-1). The 4G of PLMN-1 considers whether to allow the disaster roaming attach, thereby enabling the 4G network resources belonging to the same PLMN to be effectively utilized when the 5G network fails.
[0080] In embodiments of this disclosure, the attach denial message carries an Evolved Packet System Mobility Management (EMM) cause value, which indicates that the 4G network of the first PLMN is temporarily not allowing disaster roaming.
[0081] EMM cause value is a code used in LTE and EPS network communications to convey the cause of a specific mobility management-related event. EMM cause value can include service-related cause values that indicate that the service is temporarily unavailable. In attach denial messages, based on EMM cause value, the UE can be accurately informed that the 4G network of the first PLMN is temporarily not allowed to provide disaster roaming or disaster roaming service for some reason.
[0082] In some embodiments, if the 4G ofPLMN-1 assessment result is that disaster roaming service is temporarily unavailable, the 4G network will generate an attach denial message. This message carries an Evolved Packet System Mobility Management (EMM) reason value, which indicates that the 4G network does not allow disaster roaming temporarily. This reason value follows communication standard settings so that the UE can accurately understand the reason for the denial.
[0083] Furthermore, after receiving an attach rejection message carrying an EMM reason value, the UE will parse the message and identify the reason for the rejection. Based on the reason, the UE will mark the 4G network of the first PLMN as temporarily unavailable for disaster roaming in the network selection and roaming policy until a specified period of time has elapsed or other indications are received (such as network status updates or new roaming policy pushes), or reassess the availability of the network after a period of time.
[0084] In these embodiments, in the event of a disaster, the visiting 4G network itself may also face resource constraints. By sending an attach rejection message to the UE with an EMM reason value indicating that disaster roaming is not allowed, the 4G network of the first PLMN can effectively control the allocation of network resources and prevent network congestion or service quality degradation caused by too many disaster roaming users accessing the network.
[0085] In embodiments of this disclosure, the attach rejection message carries a timer, and the network selection method further includes: in response to the attach rejection message, starting a timer, the timer being used to time the terminal to consider the first PLMN during network selection after waiting for a set time.
[0086] Among them, the timer is a time control mechanism. When the UE receives an attach rejection message, the timer is started. By configuring and setting the time, after the set time has passed, the UE can reconsider the first PLMN that previously rejected it when making network selection.
[0087] In this embodiment, in disaster scenarios or other complex network environments, the network status is constantly changing. By configuring a timer, the UE can reapply for disaster roaming attachment from the first PLMN after waiting for a period of time, making it easier for the UE to access a higher priority network. When 4G ofPLMN-1 recovers from a state where it is temporarily unable to provide services, the UE can promptly detect and utilize this change to enhance the adaptability and flexibility of the communication system in complex environments.
[0088] In embodiments of this disclosure, the time setting is configured by the terminal based on detected network condition parameters, or the time setting is a pre-existing time parameter in the terminal, or the time setting is configured based on the value of a timer, and the attached rejection message carries the value of the timer.
[0089] In some embodiments, the UE can obtain the operating parameters of the surrounding network through its own detection mechanism. These parameters include, but are not limited to, signal strength, network load, frequency band availability, etc. Based on the changes in these parameters, the UE can dynamically configure the set time.
[0090] In some embodiments, the UE may also pre-store a fixed time parameter as a set time, which can be set by the terminal manufacturer or network operator based on experience or network planning values.
[0091] In some embodiments, the attach rejection message itself may carry the value of a timer, which the UE directly uses as the setting time. When sending the attach rejection message, the 4G network may specify an appropriate setting time for the UE based on its own network status, resource allocation strategy and other factors.
[0092] In these embodiments, by reasonably configuring the setting time, the allocation of network resources is made more scientific and reasonable, ensuring that the terminal reconsiders and selects the first PLMN at the network's expected time point, thereby optimizing the overall network service quality and resource allocation efficiency.
[0093] In embodiments of this disclosure, after receiving the attach rejection message from the first PLMN, the method further includes sending a disaster roaming registration request to the second PLMN.
[0094] In this context, since the second PLMN normally rejects the UE's access, the disaster roaming registration request is a request sent by the UE to the second PLMN (which is normally a network that is prohibited from access) in a specific scenario (such as after the first PLMN rejects disaster roaming attachment) to attempt to register in that network to obtain disaster roaming services.
[0095] In some embodiments, neither the first PLMN nor the second PLMN is the UE's home network, that is, both are visited networks of the UE. However, the UE is simultaneously within the network coverage area of the first PLMN (PLMN-1) and the second PLMN (PLMN-2). The identifier of the second PLMN belongs to the terminal's prohibited access identifier list. Under normal circumstances, the UE is not allowed to access it. However, when 5GofPLMN-1 fails, the UE affected by the failure is allowed to access PLMN-2 for disaster roaming.
[0096] In some embodiments, when the second PLMN receives a registration request, in addition to considering conventional factors such as network resources, it also needs to consider the special case of itself being prohibited from accessing the network as a UE, that is, it needs to more strictly verify the identity of the UE and the legitimacy of the request.
[0097] In some embodiments, when a UE receives an attach denial message from a first PLMN, it forwards a disaster roaming registration request to a second PLMN based on a pre-defined disaster roaming policy. Normally, the second PLMN is blocked from access, but a disaster situation can change the access rules. The UE sends a registration request, including its own identity information, to the second PLMN based on the communication protocol. Upon receiving the registration request, the second PLMN authenticates the UE, which may involve information exchange with the UE's home network or other related network entities. After successful authentication, the second PLMN decides whether to allow the UE to register and provide disaster roaming services based on its own network resources.
[0098] In this embodiment, under disaster scenarios, a large number of UEs may request attachment or service from the first PLMN, causing a sharp increase in the load on the first PLMN. When a UE receives an attachment rejection message from the first PLMN, it sends a disaster roaming registration request to the second PLMN to transfer at least some of the UEs' communication needs to the second PLMN. This reduces the network load on the first PLMN, helps the first PLMN maintain the basic stability of its network, ensures the communication quality of connected users, and also relieves pressure on the communication network of the entire disaster area. This allows resources between different PLMNs to be used more rationally, improving the overall carrying capacity and service efficiency of the communication network in a disaster environment.
[0099] In embodiments of this disclosure, sending a disaster roaming registration request to a second PLMN includes: sending a disaster roaming registration request to a 5G network belonging to the second PLMN.
[0100] In some embodiments, by sending a disaster roaming registration request to the 5G network belonging to the second PLMN, the UE affected by the 5GofPLMN-1 is allowed to access 5G of PLMN-2 for 5G disaster roaming when 5GofPLMN-1 fails.
[0101] In embodiments of this disclosure, the network selection method further includes: detecting that a timer has reached a set time, sending a disaster roaming attach request to the 4G network of the first PLMN; receiving access permission information fed back by the 4G network of the first PLMN based on the disaster roaming attach request, and accessing the 4G network of the first PLMN.
[0102] In some embodiments, when the timer is detected to have reached a set time, regardless of whether the UE has accessed the second PLMN, the UE will still send a disaster roaming attach request to the first PLMN's 4G network again because the first PLMN's 4G network has a higher priority. If the load on the first PLMN's 4G network is reduced at this time, it will send access permission information back to the UE. After receiving the information, the UE will successfully access the first PLMN's 4G network, thereby realizing network switching or accessing a higher priority network for communication.
[0103] In this embodiment, a timer mechanism is used to request disaster roaming attachment to the 4G network of the first PLMN again when the set time is reached, based on a priority strategy. This improves the flexibility and adaptability of network access, thereby enhancing the user's communication experience in complex disasters or special network environments.
[0104] In embodiments of this disclosure, the network selection method further includes: if a timer reaches a set time, and if the user has already accessed a second PLMN, no further disaster roaming attach request is sent, wherein the second PLMN refers to another non-home network of the terminal UE compared to the first PLMN.
[0105] In this embodiment, if the first PLMN cannot meet the UE's attachment requirements due to its own resource limitations, it sends an attachment rejection message with a timer to the UE. After receiving the rejection message, the UE starts the timer and sends a disaster roaming registration request to the second PLMN. When the timer reaches the set time, the UE checks its own network access status. If it has successfully accessed the second PLMN, since a communication connection has been established and considering the resource consumption and service interruption risks that may be caused by network switching, it will no longer send a disaster roaming attachment request to the first PLMN, but will continue to maintain communication in the second PLMN. This effectively reduces unnecessary network switching operations, stabilizes communication services, ensures the UE's communication needs during special periods, optimizes the overall utilization efficiency of network resources, and improves the adaptability and stability of the entire network system in complex environments.
[0106] In embodiments of this disclosure, sending a disaster roaming registration request to the second PLMN further includes:
[0107] Receive registration acceptance information from the second PLMN based on the disaster roaming registration request; or receive registration rejection information from the second PLMN based on the disaster roaming registration request.
[0108] In this embodiment, after the UE sends a disaster roaming registration request to the second PLMN, if it receives a registration acceptance message from the second PLMN, it indicates that the UE has broken through the restriction that the second PLMN is prohibited from accessing the network under normal circumstances, obtained new communication resources, and ensured the continuity of communication in special disaster scenarios; if it receives a registration rejection message, although the registration with the second PLMN fails, it helps the UE to quickly know the current network resource allocation status and adjust its strategy in a timely manner.
[0109] Figure 3 shows a flowchart of a network selection method according to an embodiment of the present disclosure.
[0110] As shown in Figure 3, the network selection method according to an embodiment of this disclosure, applied to a first PLMN (MME), includes:
[0111] In step S302, in response to the disaster roaming attach request of the terminal to be accessed, an attach rejection message is sent to the terminal to be accessed, indicating that the first PLMN temporarily does not allow disaster roaming.
[0112] In this embodiment, the terminal to be accessed refers to the terminal that issued the disaster roaming attach request to the first PLMN. On the core network element side of the first PLMN, the first PLMN sends an attach rejection message to the terminal to be accessed that issued the disaster roaming attach request, indicating that disaster roaming is temporarily not allowed. That is, the terminal is temporarily not allowed to access the first PLMN for disaster roaming, which can effectively prevent resource overload caused by too many terminals flooding into the network during a disaster.
[0113] In embodiments of this disclosure, in response to a disaster roaming attach request from a terminal to be accessed, an attach rejection message is sent to the terminal to be accessed, including:
[0114] In response to a disaster roaming attach request, check whether the number of already connected disaster roaming terminals has reached the preset access limit; if the preset access limit has been reached, send an attach rejection message to the terminal to be connected.
[0115] The preset number of connections can be a specific value or a range of values.
[0116] In this embodiment, the first PLMN responds to the disaster roaming attach request of the terminal to be accessed by triggering a detection of whether the number of already accessed disaster roaming terminals has reached the preset access limit. If the preset access limit is reached, an attach rejection message is sent. This helps to control the access scale of disaster roaming terminals and prevents excessive terminals from flooding in and causing excessive burden on key components such as network base stations, transmission links, and core network processing units. This ensures that the network as a whole can maintain a relatively stable operating state in a difficult disaster environment.
[0117] In embodiments of this disclosure, instructing the first PLMN to temporarily disallow disaster roaming includes: instructing the 4G network of the first PLMN to temporarily disallow disaster roaming.
[0118] In this embodiment, if the 4G network of the first PLMN responds to the disaster roaming attach request of the terminal to be accessed and sends an attach rejection message to it, it indicates that the UE is temporarily not allowed to access the 4G network of the first PLMN to use disaster roaming, so as to prevent excessive consumption of the 4G network resources of the first PLMN and ensure that the key components of the network can operate within the tolerable load range.
[0119] In embodiments of this disclosure, the preset access number is the maximum number of disaster roaming accesses configured in the Mobility Management Entity (MME).
[0120] Among them, the maximum number of disaster roaming accesses refers to a value pre-set in the MME by the first PLMN based on factors such as the carrying capacity of network equipment, resource status, and communication strategies in disaster scenarios. This value represents the maximum number of disaster roaming terminals that the MME allows to access simultaneously in a disaster roaming scenario.
[0121] In some embodiments, since the instruction is that the 4G network of the first PLMN is temporarily not allowed to provide disaster roaming, the network element MME of the 4G core network can carry the EMM reason value in the attach rejection message. The EMM reason value includes the "maximum number of disaster roaming accesses". By adding the "maximum number of disaster roaming accesses" parameter and processing logic to the MME, if the number of disaster roaming UEs that have been accessed exceeds this number, it means that the 4G network of the first PLMN has already accessed a large number of disaster roaming UEs and can no longer provide disaster roaming services. The MME rejects the access request or service request of the UE to be accessed and instructs the UE to be accessed not to consider this network when making network selection for a period of time.
[0122] In this embodiment, by configuring the maximum number of disaster roaming accesses in the MME, when the number of accessed disaster roaming terminals reaches the maximum number of disaster roaming accesses, the MME sends an attach rejection message to the terminal to be accessed, which helps to reduce network load and ensures stable network operation.
[0123] In embodiments of this disclosure, the MME carries an EMM cause value in the attach denial message, which is used to indicate that the 4G network of the first PLMN temporarily does not allow disaster roaming.
[0124] In this embodiment, on the UE side, a clear EMM reason value serves as an instruction to inform the UE of the reason why the 4G network of the first PLMN temporarily does not allow disaster roaming, thus preventing the UE from repeatedly initiating attach requests; on the network side, a clear indication mechanism helps maintain the stability and efficiency of the network and prevents a large influx of invalid requests.
[0125] In embodiments of this disclosure, the EMM cause value is based on existing parameter configurations of the reused MME, or the EMM cause value is based on newly added parameter configurations of the MME.
[0126] In some embodiments, the EMM cause value is configured by adding or reusing parameters, such as #42 (Severe network failure), to indicate that the UE is not allowed to access the network for disaster roaming, or that disaster roaming services are temporarily unavailable.
[0127] In embodiments of this disclosure, it further includes: an attachment rejection message carrying timer, the timer being used to time the network selection process when the terminal to be accessed considers the first PLMN after waiting for a set time.
[0128] In some embodiments, the MME is a network element of the 4G core network. When 4G of PLMN-1 rejects the UE's access request, the MME sends an attach rejection message to the UE. The attach rejection message includes an EMM cause value, which indicates that the network is temporarily unable to provide disaster roaming service. After receiving the EMM cause value, the UE starts a timer. Before the timer reaches the set time, the UE does not consider 4G of PLMN-1 when selecting PLMN. The UE continues to perform PLMN selection according to the network selection process. If there is a 5G PLMN in the forbidden list, that is, the second PLMN that can provide disaster roaming service, the UE attempts to register to the 5G PLMN. After the timer reaches the set time, the UE can consider 4G of PLMN-1 when selecting PLMN.
[0129] In this embodiment, in a disaster roaming scenario, attaching a rejection message with a timer helps the network allocate resources reasonably. By setting a timer, the network can control the access rhythm of terminals to a certain extent, ensuring the communication quality of accessing terminals and maintaining the stability and reliability of the network.
[0130] In embodiments of this disclosure, the attach rejection message also carries a timer value, which is used to determine a set time.
[0131] In some embodiments, when the MME receives a disaster roaming attach request from a terminal to be accessed, it determines the value of a timer based on the actual network conditions and service requirements. When generating an attach rejection message, the timer and its value are encapsulated in a format based on the communication protocol. In an LTE network, this information can be added to specific fields of the attach rejection message in accordance with the signaling format specified by the 3GPP standard.
[0132] In some embodiments, the rejection message carries the value of a timer, and the UE does not consider 4G ofPLMN-1 when selecting PLMN before the timer expires.
[0133] In this embodiment, the attach rejection message carries the value of the timer to determine the set time, enabling the terminal to determine how long to wait before considering the first PLMN, thus preventing the terminal from blindly and frequently attempting invalid access.
[0134] Figure 4 shows a flowchart of a network selection method according to an embodiment of the present disclosure.
[0135] As shown in Figure 4, the network selection method according to an embodiment of the present disclosure is applied to a second PLMN (AMF), including steps S402 to S404.
[0136] Step S402: Receive the disaster roaming registration request from the terminal to be connected.
[0137] Under normal circumstances, the second PLMN will refuse the UE's access. The disaster roaming registration request is a request sent by the UE to the second PLMN (which is a network that is normally prohibited from access) in a specific scenario (such as after the first PLMN refuses disaster roaming attachment) to attempt to register in that network to obtain disaster roaming services.
[0138] Step S404: Send registration acceptance information or registration rejection information to the terminal to be accessed based on the disaster roaming registration request.
[0139] In some embodiments, the second PLMN receives a disaster roaming registration request from the terminal to be accessed. The request message includes the International Mobile Subscriber Identity (IMSI), device identifier, and roaming-related parameters of the terminal to be accessed.
[0140] In some embodiments, the second PLMN verifies the legitimacy of the terminal according to its own policies and rules. Although the identifier of the second PLMN belongs to the terminal's prohibited access identifier list, the rules can be relaxed in disaster roaming scenarios. The verification process may include checking whether the terminal meets the relevant conditions for disaster roaming.
[0141] In some embodiments, if the terminal passes the legitimacy verification and the second PLMN has sufficient network resources to meet the terminal's registration requirements, the second PLMN will generate registration acceptance information; if the terminal fails the legitimacy verification or the second PLMN has insufficient network resources to accept the terminal, the second PLMN will generate registration rejection information.
[0142] In this embodiment, in a disaster scenario, the second PLMN sends registration acceptance information or registration rejection information to the terminal to be connected based on the disaster roaming registration request. If the registration acceptance information is received, the terminal can quickly access the network, obtain communication services, and meet emergency communication needs. For the second PLMN, by evaluating and deciding on the registration request, it can reasonably manage network resources in a disaster scenario, prioritize the access of terminals that meet the conditions and have urgent needs, and enable network resources to be allocated and utilized more effectively.
[0143] In embodiments of this disclosure, the disaster roaming registration request includes a disaster roaming identifier, and based on the identification result of the disaster roaming identifier, registration acceptance information or registration rejection information is sent to the terminal to be accessed.
[0144] The disaster roaming identifier can be understood as a special identifier carried in the disaster roaming registration request. It is used to provide the second PLMN with an identification and judgment mechanism to determine whether the registration request is a legitimate need originating from a disaster scenario.
[0145] In this embodiment, by configuring a disaster roaming identifier, on the one hand, the terminal carries the disaster roaming identifier to initiate a registration request, increasing the chance of obtaining emergency communication services; on the other hand, the disaster roaming identifier provides a filtering mechanism for the second PLMN to distinguish between ordinary network access requests and special requests under disaster scenarios.
[0146] Figure 4 shows a flowchart of a network selection method in an embodiment of this disclosure. When 5G ofPLMN-1 enters a fault state and cannot provide 5G service, the UE selects a network sequentially according to the existing network selection process. Available networks include 4G ofPLMN-1 and other forbidden PLMNs providing disaster roaming services. Since PLMN-1 is not a forbidden PLMN, the UE preferentially selects 4G ofPLMN-1 and initiates a disaster roaming attach request. As shown in Figure 5, the network selection method includes steps S502 to S514.
[0147] In step S502, the UE sends a disaster roaming attach request.
[0148] In step S504, the MME sends an attach rejection message to the first PLMN.
[0149] The 4G of PLMN-1 is configured to provide disaster roaming service, and the MME is configured with a "maximum number of disaster roaming accesses". If the number of disaster roaming UEs connected to the 4G of PLMN-1 exceeds the "maximum number of disaster roaming accesses", it means that the current 4G network has connected a large number of disaster roaming UEs and can no longer provide disaster roaming service. The MME sends an access denial message to the UE and carries the EMM cause and / or timer in the message to indicate that the 4G network of the first PLMN does not allow disaster roaming for the time being. The EMM cause can reuse existing parameters, such as #42 (Severe network failure), or add new parameters.
[0150] In step S506, when the UE determines the network selection, it does not consider the first PLMN, starts a timer, and performs network selection.
[0151] In this process, the UE confirms that the selected network is temporarily unable to provide disaster roaming service based on the EMM cause and starts a timer. Before the timer expires, the UE does not consider 4G ofPLMN-1 when selecting a PLMN. If the message carries the value of the timer, the UE uses the value sent by the network to set the timer's set time. After the terminal waits for the set time, it considers the first PLMN when selecting a network for timing.
[0152] In step S508, the UE sends a disaster roaming registration request.
[0153] In this process, the UE enters the "EMM-Unregistered.PLMN Search" state and continues to perform PLMN selection according to the network selection process. The UE selects the 5G PLMN in the forbidden list, namely 5G ofPLMN-2, and initiates a disaster roaming registration request.
[0154] Step S510: AMF receives confirmation of registration information.
[0155] In step S512, the UE detects that the timer has expired and sends a disaster roaming attach request.
[0156] Step S514: The MME sends back the access acceptance information.
[0157] If no other PLMN providing disaster roaming service is selected after the timer expires, the UE will consider 4G ofPLMN-1 when selecting the PLMN and try to access it again.
[0158] In this embodiment, when congestion occurs due to the arrival of roaming users in disaster-related situations, the 4G ofPLMN-1 network indicates that it cannot accept roaming users in disaster-related situations by carrying an Evolved Packet System Mobility Management (EMM) reason value in the attach denial message.
[0159] When a UE receives an attach rejection message with the EMM reason value #YYY "Disaster entry into roaming users is temporarily not allowed", it starts an implementation-specific timer. If the rejection message contains a timer value, the timer's set time is set to that value. During the timer's operation, the UE should not consider the combination of the Public Land Mobile Network (PLMN) and Radio Access Technology (RAT) that gives this rejection reason as a candidate for PLMN selection. Then, the UE enters the "EMM-Unregistered.PLMN Search" state to perform PLMN selection according to 3GPP TS23.122.
[0160] It should be noted that the above figures are merely illustrative of the processes included in the method according to exemplary embodiments of the present invention, and are not intended to be limiting. It is readily understood that the processes shown in the above figures do not indicate or limit the temporal order of these processes. Furthermore, it is readily understood that these processes may, for example, be executed synchronously or asynchronously in multiple modules.
[0161] The following embodiments of this disclosure relate to an apparatus that can be used to perform the methods involved in the above embodiments of this disclosure. For details not disclosed in the following embodiments of the apparatus, please refer to the embodiments of the methods involved in this disclosure.
[0162] The network selection device 600 according to an embodiment of the present invention will now be described with reference to FIG6. The network selection device 600 shown in FIG6 is merely an example and should not be construed as limiting the functionality and scope of use of the embodiments of the present invention.
[0163] The network selection device 600 is manifested as a hardware module. Components of the network selection device 600 may include, but are not limited to: a first sending module 602, used to send a disaster roaming attach request to a first public terrestrial mobile network (PLMN); and a first receiving module 604, used to receive an attach rejection message from the first PLMN, regardless of the first PLMN.
[0164] The network selection device 700 according to an embodiment of the present invention will now be described with reference to FIG7. The network selection device 700 shown in FIG7 is merely an example and should not impose any limitation on the functionality and scope of use of the embodiments of the present invention.
[0165] The network selection device 700 is manifested as a hardware module. Components of the network selection device 700 may include, but are not limited to: a second sending module 702, used to send an attach rejection message to the terminal to be accessed in response to a disaster roaming attach request from the terminal to be accessed, instructing the first PLMN to temporarily disallow disaster roaming.
[0166] The network selection device 800 according to an embodiment of the present invention will now be described with reference to FIG8. The network selection device 800 shown in FIG8 is merely an example and should not be construed as limiting the functionality and scope of use of the embodiments of the present invention.
[0167] The network selection device 800 is manifested as a hardware module. Components of the network selection device 800 may include, but are not limited to: a second receiving module 802, used to receive a disaster roaming registration request from a terminal to be accessed; and a third sending module 804, used to send registration acceptance information or registration rejection information to the terminal to be accessed based on the disaster roaming registration request.
[0168] Those skilled in the art will understand that the technical solutions of various aspects of the present invention can be implemented as systems, methods, or program products. Therefore, various aspects of the present invention can be specifically implemented in the following forms: a completely hardware implementation, a completely software implementation (including firmware, microcode, etc.), or a combination of hardware and software. The terms "circuit," "module," or "system" as used herein can be understood as purely software implementation, purely hardware implementation, or a combination of software and hardware implementation.
[0169] The electronic device 900 according to an embodiment of the present invention will now be described with reference to FIG9. The electronic device 900 may be a network device or a terminal. The electronic device 900 shown in FIG9 is merely an example and should not impose any limitation on the functionality and scope of use of the embodiments of the present invention.
[0170] As shown in Figure 9, the electronic device 900 is presented in the form of a general-purpose computing device. The components of the electronic device 900 may include, but are not limited to: at least one processing unit 910, at least one storage unit 920, and a bus 930 connecting different system components (including the storage unit 920 and the processing unit 910).
[0171] The storage unit 920 stores program code that can be executed by the processing unit 910, causing the processing unit 910 to perform the steps of the methods according to various exemplary embodiments of the present invention described in this specification. For example, the processing unit 910 can execute the scheme described in FIG2 to 5.
[0172] Storage unit 920 may include transient and non-transient storage media. As shown in FIG9, storage unit 920 may include readable media in the form of volatile storage units, such as random access memory (RAM) 9201 and / or cache memory 9202, and may further include non-volatile readable media, such as read-only memory (ROM) 9203.
[0173] Storage unit 920 may also include a program / utility 9204 having a set (at least one) program module 9205, such program module 9205 including but not limited to: operating system, one or more application programs, other program modules and program data, each or some combination of these examples may include an implementation of a network environment.
[0174] Bus 930 can represent one or more of several types of bus structures, including a memory cell bus or memory cell controller, a peripheral bus, a graphics acceleration port, a processing unit, or a local bus using any of the various bus structures.
[0175] Electronic device 900 can also communicate with one or more external devices 970 (e.g., keyboard, pointing device, Bluetooth device, etc.), and with one or more devices that enable a user to interact with electronic device 900, and / or with any device that enables electronic device 900 to communicate with one or more other computing devices (e.g., router, modem, etc.). This communication can be performed via input / output (I / O) interface 950. Furthermore, electronic device 900 can also communicate with one or more networks (e.g., local area network (LAN), wide area network (WAN), and / or public networks, such as the Internet) via network adapter 960. As shown, network adapter 960 communicates with other modules of electronic device 900 via bus 930. It should be understood that, although not shown in the figures, other hardware and / or software modules can be used in conjunction with electronic device 900, including but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data backup storage systems.
[0176] From the above description of the embodiments, those skilled in the art will readily understand that the exemplary embodiments described herein can be implemented by software or by combining software with necessary hardware. Therefore, the technical solutions according to the embodiments of this disclosure can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (such as a CD-ROM, USB flash drive, external hard drive, etc.) or on a network, including several instructions to cause a computing device (such as a personal computer, server, terminal device, or network device, etc.) to execute the methods according to the embodiments of this disclosure.
[0177] In exemplary embodiments of this disclosure, a non-transient computer-readable storage medium is also provided, on which a program product capable of implementing the methods described above is stored. In some possible embodiments, various aspects of the invention may also be implemented as a program product comprising program code that, when the program product is run on an electronic device, causes the electronic device to perform the steps of the methods of the various exemplary embodiments described in this specification.
[0178] According to embodiments of the present invention, a program product for implementing the above-described method may employ a portable compact disc read-only memory (CD-ROM) and include program code, and may run on an electronic device, such as a personal computer. However, the program product of the present invention is not limited thereto. In this document, a readable storage medium may be any tangible medium containing or storing a program that may be used by or in conjunction with an instruction execution system, apparatus, or device.
[0179] The program product may employ any combination of one or more readable media. A readable medium may be a readable signal medium or a readable storage medium. A readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of readable storage media (a non-exhaustive list) include: an electrical connection having one or more wires, a portable disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.
[0180] Computer-readable signal media may include data signals propagated in baseband or as part of a carrier wave, carrying readable program code. Such propagated data signals may take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. A readable signal medium may also be any readable medium other than a readable storage medium, capable of sending, propagating, or transmitting programs for use by or in conjunction with an instruction execution system, apparatus, or device.
[0181] The program code contained on the readable medium may be transmitted using any suitable medium, including but not limited to wireless, wired, optical fiber, RF, etc., or any suitable combination thereof.
[0182] Program code for performing the operations of this invention can be written in any combination of one or more programming languages, including object-oriented programming languages such as Java and C++, and conventional procedural programming languages such as C or similar languages. The program code can execute entirely on the user's computing device, partially on the user's device, as a standalone software package, partially on the user's computing device and partially on a remote computing device, or entirely on a remote computing device or server. In cases involving remote computing devices, the remote computing device can be connected to the user's computing device via any type of network, including a local area network (LAN) or a wide area network (WAN), or it can be connected to an external computing device (e.g., via the Internet using an Internet service provider).
[0183] It should be noted that although several modules or units for the device used to perform actions have been mentioned in the detailed description above, this division is not mandatory. In fact, according to embodiments of this disclosure, the features and functions of two or more modules or units described above can be embodied in one module or unit. Conversely, the features and functions of one module or unit described above can be further divided and embodied by multiple modules or units.
[0184] Furthermore, although the steps of the method in this disclosure are described in a specific order in the accompanying drawings, this does not require or imply that the steps must be performed in that specific order, or that all the steps shown must be performed to achieve the desired result. Additional or alternative steps may be omitted, multiple steps may be combined into one step, and / or a step may be broken down into multiple steps.
[0185] From the above description of the embodiments, those skilled in the art will readily understand that the exemplary embodiments described herein can be implemented by software or by combining software with necessary hardware. Therefore, the technical solutions according to the embodiments of this disclosure can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (such as a CD-ROM, USB flash drive, external hard drive, etc.) or on a network, including several instructions to cause a computing device (such as a personal computer, server, mobile terminal, or network device, etc.) to execute the methods according to the embodiments of this disclosure.
[0186] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the appended claims.
Claims
1. A network selection method, applied to a terminal, comprising: Send a disaster roaming attach request to the first public terrestrial mobile network (PLMN); Receive the attach rejection message from the first PLMN, without considering the first PLMN.
2. The network selection method according to claim 1, wherein, Send a disaster roaming attach request to the first PLMN, including: The disaster roaming attach request is sent to the 4th Generation Mobile Communication Technology (4G) network belonging to the first PLMN, wherein the 5th Generation Mobile Communication Technology (5G) network belonging to the first PLMN has entered a fault state.
3. The network selection method of claim 2, wherein, The attach denial message carries an Evolved Packet System Mobility Management (EMM) cause value, which indicates that the 4G network of the first PLMN temporarily does not allow disaster roaming.
4. The network selection method of claim 1, wherein, The attach rejection message carries a timer, and the network selection method further includes: In response to the attach rejection message, the timer is started. The timer is used to time the terminal to wait for a set time before considering the first PLMN during network selection.
5. The network selection method according to claim 4, wherein, The set time is configured by the terminal based on detected network condition parameters, or the set time is a time parameter pre-existing in the terminal, or the set time is configured based on the value of the timer, and the attach rejection message carries the value of the timer.
6. The network selection method according to claim 4 further includes: Upon detecting that the timer has reached the set time, the disaster roaming attach request is sent to the 4G network of the first PLMN; Receive the access permission information fed back by the 4G network based on the disaster roaming attach request, and access the 4G network.
7. The network selection method according to claim 4, further comprising: If the timer reaches the set time, and the terminal has already connected to the second PLMN, the disaster roaming attach request will no longer be sent.
8. The network selection method of claim 1, wherein, After receiving the attach rejection message from the first PLMN, the process also includes: Send a disaster roaming registration request to the second PLMN.
9. The network selection method of claim 8, wherein, After sending a disaster roaming registration request to the second PLMN, the process also includes: Receive the registration acceptance information from the second PLMN based on the disaster roaming registration request; or Receive the registration rejection information from the second PLMN based on the disaster roaming registration request.
10. The network selection method of claim 8, wherein, Send a disaster roaming registration request to the second PLMN, including: The disaster roaming registration request is sent to the 5G network belonging to the second PLMN.
11. The network selection method according to claim 8, wherein, The first PLMN is the visited network of the terminal, and the identifier of the second PLMN belongs to the prohibited access identifier list of the terminal.
12. A network selection method applied to a first public land mobile network (PLMN), comprising: In response to a disaster roaming attach request from a terminal to be connected, an attach rejection message is sent to the terminal to be connected, indicating that the first PLMN temporarily does not allow disaster roaming.
13. The network selection method of claim 12, wherein, In response to a disaster roaming attach request from a terminal to be accessed, an attach rejection message is sent to the terminal to be accessed, including: In response to the disaster roaming attach request, it is detected whether the number of disaster roaming terminals that have been connected to the first PLMN has reached the preset number of connections; If the preset access limit is reached, the attach rejection message is sent to the terminal to be accessed.
14. The network selection method of claim 12, wherein, The first PLMN is instructed to temporarily prohibit disaster roaming, including: The system instructs the first PLMN's 4G network to temporarily disable the disaster roaming.
15. The network selection method according to claim 13, wherein, The preset access limit is the maximum number of disaster roaming accesses configured in the Mobility Management Entity (MME).
16. The network selection method according to claim 15, wherein, The MME carries an Evolved Packet System Mobility Management (EMM) cause value in the attach denial message, which is used to indicate that the first PLMN's 4G network temporarily does not allow the disaster roaming.
17. The network selection method according to claim 16, wherein, The EMM cause value is based on the existing parameter configuration of the MME, or the EMM cause value is based on the newly added parameter configuration of the MME.
18. The network selection method according to claim 12, wherein: The attach rejection message carries a timer, which is used to time the network selection process when the terminal to be accessed considers the first PLMN after waiting for a set time.
19. The network selection method according to claim 18, wherein, The attach rejection message also carries the value of the timer, which is used to determine the set time.
20. A network selection method applied to a second public land mobile network (PLMN), comprising: Receive disaster roaming registration requests from terminals to be connected; Based on the disaster roaming registration request, send registration acceptance information or registration rejection information to the terminal to be connected.
21. The network selection method according to claim 20, wherein, The disaster roaming registration request includes a disaster roaming identifier, and sending acceptance registration information or rejection registration information to the terminal to be accessed based on the disaster roaming registration request includes: sending the acceptance registration information or the rejection registration information to the terminal to be accessed based on the identification result of the disaster roaming identifier.
22. A network selection device, comprising: The first sending module is used to send a disaster roaming attach request to the first public terrestrial mobile network (PLMN); The first receiving module is used to receive the attach rejection message of the first PLMN, without considering the first PLMN.
23. A network selection device, comprising: The second sending module is used to send an attach rejection message to the terminal to be accessed in response to the disaster roaming attach request of the terminal to be accessed, indicating that the first public land mobile network (PLMN) temporarily does not allow disaster roaming.
24. A network selection device, comprising: The second receiving module is used to receive disaster roaming registration requests from terminals to be connected; The third sending module is used to send registration acceptance information or registration rejection information to the terminal to be accessed based on the disaster roaming registration request.
25. A terminal, comprising: processor; as well as Memory for storing the executable instructions of the processor; The processor is configured to execute the network selection method of any one of claims 1 to 11 by executing the executable instructions.
26. A network device, comprising: processor; as well as Memory for storing the executable instructions of the processor; The processor is configured to execute the network selection method of any one of claims 12 to 19 by executing the executable instructions.
27. A network device, comprising: processor; as well as Memory for storing the executable instructions of the processor; The processor is configured to execute the network selection method of claim 20 or 21 by executing the executable instructions.
28. A non-transitory computer readable storage medium having stored thereon a computer program, wherein, When the computer program is executed by the processor, the processor performs the network selection method according to any one of claims 1 to 21.
29. A computer program product having stored thereon a computer program, the computer program comprising: computer readable program means for causing a computer to perform the steps of any of claims 1-28. When the computer program is executed by the processor, the processor performs the network selection method according to any one of claims 1 to 21.