Network selection method and device

Abstract

The present application relates to a network selection method and a terminal. The method comprises: when a terminal establishes a first connection in a first network, the terminal selects a second network on the basis of first information.

Description

Network selection methods and equipment Technical Field

[0001] This application relates to the field of communications, and more specifically, to a network selection method and apparatus. Background Technology

[0002] As terminal capabilities continue to improve, future terminals may support multi-connection functionality or capabilities, meaning simultaneous data transmission across multiple base stations and / or core networks. However, how terminals can select from multiple networks and establish multiple connections across those networks to enable data transmission via multiple connections becomes a problem that needs to be solved.

[0003] Summary of the Invention

[0004] This application provides a network selection method and device.

[0005] This application provides a network selection method, including:

[0006] When a terminal establishes a first connection under a first network, the terminal selects a second network based on first information.

[0007] This application provides a network selection method, including:

[0008] The first core network device sends first information to the terminal, wherein the first information is used by the terminal to select a second network.

[0009] This application provides a terminal, including:

[0010] The first processing unit is used to select a second network based on first information when a first connection is established under the first network.

[0011] This application provides a first core network device, including:

[0012] The second communication unit is used to send first information to the terminal, wherein the first information is used by the terminal to select a second network.

[0013] This application provides a terminal, including a transceiver, a processor, and a memory. The memory stores a computer program, the transceiver communicates with other devices, and the processor calls and runs the computer program stored in the memory to enable the terminal to perform the methods described above.

[0014] This application provides a first core network device, including a transceiver, a processor, and a memory. The memory stores a computer program, the transceiver communicates with other devices, and the processor calls and runs the computer program stored in the memory to cause the first core network device to perform the aforementioned method.

[0015] This application provides a chip for implementing the above method.

[0016] Specifically, the chip includes a processor for retrieving and running a computer program from memory, causing a device equipped with the chip to perform the methods described above.

[0017] This application provides a computer-readable storage medium for storing a computer program, which, when run by a device, causes the device to perform the above-described method.

[0018] This application provides a computer program product, including computer program instructions that cause a computer to perform the above-described method.

[0019] By adopting the above scheme, the terminal can, after establishing a first connection on the first network, further select a second network based on the first information. In this way, the terminal can combine the first information to select more networks, thereby enabling the terminal to establish multiple connections across multiple networks and ultimately achieve data transmission through multiple connections. Attached Figure Description

[0020] Figure 1 is a schematic diagram of an application scenario according to an embodiment of this application.

[0021] Figure 2 is a schematic flowchart of a network selection method according to an embodiment of this application.

[0022] Figure 3 is a schematic flowchart of a network selection method according to another embodiment of this application.

[0023] Figure 4 is a schematic flowchart of the PLMN selection mechanism according to an embodiment of this application.

[0024] Figure 5 is a schematic block diagram of a terminal according to an embodiment of this application.

[0025] Figure 6 is a schematic block diagram of a first core network device according to an embodiment of this application.

[0026] Figure 7 is a schematic block diagram of a communication device according to an embodiment of this application.

[0027] Figure 8 is a schematic block diagram of a chip according to an embodiment of this application.

[0028] Figure 9 is a schematic block diagram of a communication system according to an embodiment of this application. Detailed Implementation

[0029] The technical solutions of this application embodiment can be applied to various communication systems, such as: LTE (Long Term Evolution), LTE-A (Long Term Evolution-Advanced), NR (New Radio), evolution of NR, WLAN (Wireless Local Area Network), WiFi (Wireless Fidelity), or other communication systems.

[0030] This application describes various embodiments in conjunction with network devices and terminals. The terminal can be mobile or fixed, and may also be referred to as a mobile station, user unit, etc. The terminal can be a station in a WLAN, or a smart terminal, wireless modem, laptop, tablet, etc. In this application embodiment, the terminal can be a VR (Virtual Reality) terminal / AR (Augmented Reality) terminal, industrial control terminal, autonomous driving terminal, telemedicine terminal, smart grid terminal, transportation safety terminal, smart city terminal, or smart home wireless terminal, etc. By way of example and not limitation, in this application embodiment, the terminal can also be a wearable device.

[0031] In this embodiment, the network device can be a device for communicating with a terminal. The network device can be an access point in a WLAN, an evolved base station in LTE, a relay station, a vehicle-mounted device, a wearable device, a network device in an NR network (gNB, the next generation Node B), a network device in a future PLMN network, or a network device in a non-terrestrial network, etc. By way of example and not limitation, in this embodiment, the network device can have mobility characteristics; for example, the network device can be a mobile device.

[0032] To facilitate understanding of the technical solutions of the embodiments of this application, the relevant technologies of the embodiments of this application are described below. The following relevant technologies are optional solutions and can be combined with the technical solutions of the embodiments of this application in any way, and they all fall within the protection scope of the embodiments of this application.

[0033] Figure 1 exemplarily illustrates a communication system 100. The communication system includes network devices 110 and terminals 120. In one possible implementation, the communication system 100 may include multiple network devices 110, and the coverage area of ​​each network device 110 may include one or more terminals 120; this embodiment does not limit this. In another possible implementation, the communication system 100 may also include other network entities such as mobility management entities and access and mobility management functions; this embodiment does not limit this. The network devices may further include access network devices and core network devices. That is, the communication system may also include multiple core networks for communicating with the access network devices. The access network devices may be base stations of LTE, LTE-A, or NR systems. Taking the communication system shown in Figure 1 as an example, the communication devices may include network devices and terminals with communication functions. The communication devices may also include other devices in the communication system, such as network controllers, mobility management entities, and other network entities; this embodiment does not limit this.

[0034] Figure 2 is a schematic flowchart of a network selection method according to an embodiment of this application. The method includes at least a portion of the following.

[0035] S210. When the terminal establishes a first connection under the first network, the terminal selects a second network based on the first information.

[0036] Figure 3 is a schematic flowchart of a network selection method according to an embodiment of this application. The method includes at least a portion of the following.

[0037] S410. The first core network device sends first information to the terminal, wherein the first information is used by the terminal to select a second network.

[0038] In some possible implementations, the terminal enables multi-connection functionality before selecting a network (e.g., at least before selecting a first network and a second network).

[0039] In one embodiment, before the terminal establishes a first connection under the first network or before the terminal begins to select any network, the process may further include: the terminal receiving a multi-connection enable instruction, wherein the multi-connection enable instruction is used by the terminal to enable the multi-connection function.

[0040] The multi-connection enable indicator can be represented as an "Enabling DualSteer" indicator, or an enable multi-connection indicator, etc.

[0041] The terminal receiving the multi-connection enable instruction can be described as follows: the terminal receives a multi-connection enable instruction from a first core network device. Correspondingly, the processing by the first core network device further includes: the first core network device sending a multi-connection enable instruction to the terminal, wherein the multi-connection enable instruction is used by the terminal to enable the multi-connection function.

[0042] The first core network device may be any control plane network element on the core network side. For example, the first core network device may include AMF (Access and Mobility Management Function), etc. Here, we will not limit or exhaust all possible device types of the first core network device.

[0043] For example, the multi-connection enable indication can be carried by the first NAS (Non-Access Stratum) message, which may include a DL (Downlink) NAS Transport message, or a registration reply, etc.

[0044] It should be noted that the timing of receiving or sending the multi-connection enable indication is within the scope of protection of this embodiment as long as it occurs before the terminal begins to select any network. This application does not limit the timing of receiving or sending the multi-connection enable indication, nor does it limit the specific process through which the multi-connection enable indication is transmitted.

[0045] After receiving a multi-connection enable instruction, a terminal can enable or enable the multi-connection function. A terminal that supports or is able to use the multi-connection function (or capability) can be called a multi-connection terminal (or DualSteer terminal).

[0046] This multi-connection function can also be alternatively referred to as DualSteer function, multi-connection capability, or DualSteer capability, etc. In this way, the terminal can be enabled or deactivated by commands from the network side.

[0047] Multi-connection functionality refers to the ability of a terminal to register and establish multiple connections with multiple access network devices and / or multiple core networks.

[0048] The terminal can be a single-card terminal or a multi-card terminal; a single-card terminal can refer to a terminal with a single USIM (Universal Subscriber Identity Module) card, while a multi-card terminal can refer to a terminal with multiple USIM cards.

[0049] Registration can refer to NAS registration.

[0050] Different connections within a network correspond to different access network devices and / or different core networks. A connection can be one of the following: a PDU (Protocol Data Unit) session, a PDN (Packet Data Network Connection), a user plane connection, etc.

[0051] Optionally, the RAT (Radio Access Technology) corresponding to different access network devices among multiple access network devices can be the same or different.

[0052] The RAT corresponding to any one of the multiple access network devices can be at least one of the following: E-UTRA (Evolved Universal Terrestrial Radio Access), NR terrestrial access, NR satellite access, etc. Here, we do not limit or exhaustively list the RATs corresponding to each access network device.

[0053] Optionally, the networks in which different access network devices reside can be of the same or different types.

[0054] The network type of any one of the multiple access network devices can be one of the following: TN (Terrestrial Network) or NTN (Non-Terrestrial Network). And / or the network type of any one of the multiple access network devices can be one of the following: PLMN (Public Land Mobile Network) or NPN (Non-public network). Here, we do not limit or exhaustively list the network types of each access network device.

[0055] Optionally, the system types corresponding to different access network devices among multiple access network devices (or the system types corresponding to the networks where different access network devices are located among multiple access network devices) can be the same or different.

[0056] The system type corresponding to any one of the multiple access network devices can be one of the following: 6GS (6th Generation System), 5GS (5th Generation System), or EPS (Evolved Packet System). Here, we do not limit or exhaustively list the system types corresponding to each access network device.

[0057] In one embodiment, the terminal can determine on its own whether to enable the multi-connection function or enable the multi-connection capability. In this embodiment, the terminal does not need to receive an enable multi-connection instruction from the network side.

[0058] In some possible implementations, the terminal may determine or obtain first information before selecting a network (e.g., at least selecting a first network and selecting a second network).

[0059] The first information may include at least one of the following: the RAT and / or network corresponding to the first connection, the RAT and / or network corresponding to the second connection, the priority of the RAT and / or network corresponding to the first connection, the priority of the RAT and / or network corresponding to the second connection, and the association between the RAT and / or network of the first connection and the second connection.

[0060] The first information may be presented as a list, in sequence, implicitly, explicitly, or in other ways, including the above. In some possible examples, the first information may also be referred to as a second list, or the first information may include a list corresponding to a first connection and / or a list corresponding to a second connection. The list corresponding to the first connection may include the RAT and / or network corresponding to the first connection, and the priority of the RAT and / or network corresponding to the first connection; the list corresponding to the second connection may include the RAT and / or network corresponding to the second connection, and the priority of the RAT and / or network corresponding to the second connection, etc.

[0061] In one embodiment, on the terminal side, the first information is either default or specified by the protocol. In this case, the first information may be configured locally by default on the terminal, or the first information may be configured locally on the terminal based on the protocol. Here, we do not limit how the first information is specifically configured locally on the terminal.

[0062] In one embodiment, on the terminal side, the first information is configured or pre-configured.

[0063] In this scenario, the terminal's processing may further include: the terminal receiving the first information. Here, the terminal receiving the first information may refer to: the terminal receiving first information from the first core network device. Correspondingly, the processing by the first core network device involves the first core network device sending the first information to the terminal.

[0064] The description of the first core network device is the same as that in the aforementioned embodiments and will not be repeated. For example, the first information can be configured to the terminal via a second NAS message and / or via a Steer of Roaming (SoR) container.

[0065] For example, the first information and the multi-connection enable indication may be transmitted simultaneously. For instance, the first NAS message and the second NAS message may be the same, meaning the first information can also be carried by the first NAS message. Thus, the terminal can receive a first NAS message from the first core network device carrying the first information and the multi-connection enable indication. Alternatively, the first information and the multi-connection enable indication may not be transmitted simultaneously. For example, the first information may be carried by a second NAS message, which is different from the first NAS message.

[0066] It should be noted that the timing of receiving or sending the first information is within the scope of protection of this embodiment as long as it occurs before the terminal begins to select any network. This application does not limit the timing of receiving or sending the first information. This embodiment also does not limit the specific process through which the first information is transmitted.

[0067] In some possible implementations, the first information includes at least one of the following: one or more Radio Access Technologies (RATs) corresponding to the second connection, the priority of one or more RATs corresponding to the second connection, one or more networks corresponding to the second connection, the priority of one or more networks corresponding to the second connection, one or more combination information corresponding to the second connection, and the priority of one or more combination information corresponding to the second connection, wherein the combination information includes the network and the RAT, and the second connection is established by the terminal under the second network.

[0068] The one or more RATs corresponding to the second connection can also be referred to as the RAT list corresponding to the second connection. The one or more RATs corresponding to the second connection can be represented by the name of each RAT within the one or more RATs corresponding to the second connection. The one or more RATs corresponding to the second connection can be configured according to actual needs. For example, any RAT corresponding to the second connection can be one of the following: E-UTRA, NR terrestrial access, NR satellite access, etc. It should be noted that this is only an illustrative description of the RATs corresponding to the second connection; in reality, the RATs corresponding to the second connection can include, but are not limited to, at least one of the examples above. This is not a limitation or an exhaustive list.

[0069] The priority of one or more RATs corresponding to the second connection can also be configured according to the actual situation. The priorities of different RATs corresponding to the second connection can be the same or different. For example, if there are four RATs corresponding to the second connection, namely RAT-a, RAT-b, RAT-c, and RAT-d, RAT-a can be the highest priority, RAT-b and RAT-c can be medium priority, and RAT-d can be the lowest priority; or, RAT-a can be the highest priority, RAT-b can be the second highest priority, RAT-c can be the third highest priority, and RAT-d can be the lowest priority.

[0070] Optionally, the priority of one or more RATs corresponding to the second connection can be the content explicitly indicated in the first information, that is, the priority of each RAT corresponding to the second connection can be directly included in the first information.

[0071] For example, a description field can be used to represent the priority of each RAT. For instance, the priority of a certain RAT corresponding to the second connection can be "highest", "top", "medium", "middle", "lowest", or "lowest", etc.

[0072] For another example, numerical information can be used to represent the priority of each RAT, with smaller values ​​indicating higher priority. Suppose the first information includes three RATs corresponding to the second connection: RAT-1, RAT-2, and RAT-3. The first information also explicitly indicates that RAT-1 has a priority of "01" or "first priority" or "first," RAT-2 has a priority of "02" or "second priority," and RAT-3 has a priority of "03" or "third priority." This means that RAT-1 has the highest priority, RAT-2 has the second highest priority, and RAT-3 has the lowest priority.

[0073] Optionally, the priority of one or more RATs corresponding to the second connection can be implicitly indicated in the first information. Specifically, the priority of one or more RATs corresponding to the second connection can be related to the order in which the one or more RATs corresponding to the second connection are arranged in the first information.

[0074] For example, if one or more RATs corresponding to the second connection are arranged in a column from top to bottom in the first information, then the priority of one or more RATs decreases as they go down. For example, the RATs in the first row are the highest priority RATs, the RATs in the second row are lower priority than the RATs in the first row, and so on, with the RATs in the last row being the lowest priority RATs.

[0075] For another example, if one or more RATs corresponding to the second connection are arranged in a row from left to right in the first information, then the priority of one or more RATs decreases from left to right (or vice versa). For example, the leftmost RAT is the highest priority RAT, and so on, with the rightmost RAT being the lowest priority RAT.

[0076] The one or more networks corresponding to the second connection (or the list of networks corresponding to the second connection) can be represented by at least one of the following: the type of each network, the number (e.g., ID) of each network, and the system type corresponding to each network.

[0077] The type of any network corresponding to the second connection can be one of the following: TN, NTN, PLMN, NPN. And / or, the system type corresponding to any network corresponding to the second connection can include one of the following: 6GS, 5GS, EPS.

[0078] The priority of one or more networks corresponding to the second connection can be configured according to the actual situation. The priorities of different networks corresponding to the second connection can be the same or different. For example, assuming the network is a PLMN, there are 4 PLMNs corresponding to the second connection, namely PLMN-a, PLMN-b, PLMN-c, and PLMN-d. Among them, PLMN-a can be the highest priority, PLMN-d can be the medium priority, and PLMN-c and PLMN-b can be the lowest priority.

[0079] The priority of one or more networks corresponding to the second connection is indicated in the first information in two ways: explicitly or implicitly. The method of explicitly or implicitly indicating the priority of one or more networks corresponding to the second connection in the first information is similar to the explanation of explicitly or implicitly indicating the priority of one or more RATs corresponding to the second connection in the first information, and therefore will not be repeated.

[0080] Any combination of information corresponding to the second connection includes: the network and RAT corresponding to the second connection, wherein the network can be represented by a network number and / or identifier, and the RAT can be represented by a name.

[0081] The priority of one or more combinations of information corresponding to the second connection can be configured according to the actual situation. The priorities of different combinations of information can be the same or different. For example, there are three combinations of information corresponding to the second connection: combination information 1, combination information 2, and combination information 3. Combination information 1 can be the highest priority, combination information 2 can be the medium priority, and combination information 3 can be the lowest priority; or combination information 1 can be the highest priority, and combination information 2 and combination information 3 can be the lowest priority.

[0082] The priority of one or more combined information corresponding to the second connection is indicated in the first information in two ways: explicitly or implicitly. The method of explicitly or implicitly indicating the priority of one or more combined information corresponding to the second connection in the first information is similar to the explanation of explicitly or implicitly indicating the priority of one or more RATs corresponding to the second connection in the first information, and therefore will not be repeated.

[0083] It should be noted that the above is only an exemplary description of the explicit or implicit indication of the priority of one or more RATs, one or more networks, or one or more combined information corresponding to the second connection in the first information. In actual processing, other methods may be used to represent the priority. As long as the priority of each RAT, each network, or each combined information can be determined through the first information, it is within the protection scope of this embodiment, and no limitation or exhaustive list is made here.

[0084] In one embodiment, the terminal selecting a second network based on first information may include: the terminal selecting a second optional network based on a network selection mechanism; and the terminal using the second optional network as the second network if the second optional network matches the first information.

[0085] The network selection mechanism can refer to the PLMN (Public Land Mobile Network) selection mechanism. This PLMN selection mechanism can be the PLMN selection mechanism specified in relevant protocols (such as 3GPP TS23.122).

[0086] The PLMN selection mechanism allows a terminal to select networks based on their priority order. Any network searched by the terminal can refer to the network for which the terminal detected or received signals. This PLMN selection mechanism allows the terminal to determine the following priority order: first, select an RPLMN (Registered Public Land Mobile Network), then select one or more other PLMNs (or combinations of other PLMNs and RATs) included in the first list.

[0087] RPLMN can refer to the PLMN registered by the terminal.

[0088] The first list may include at least one of the following:

[0089] i) HPLMN (if the EHPLMN list does not exist or is empty) or the highest priority EHPLMN available (if the EHPLMN list exists);

[0090] ii) Each PLMN / access technology combination (in order of priority) in the "User Controlled PLMN Selector and Access Technology (RAT)" data file in the SIM;

[0091] iii) Each PLMN / access technology combination in the "Operator-Controlled PLMN Selector with Access Technology" data file in the SIM (in order of priority) or stored in the ME (in order of priority);

[0092] iv) Other combinations of PLMN and Radio Access Technology (RAT) to receive high-quality signals in random order;

[0093] v) Allow other PLMN and RAT combinations in descending order of signal quality.

[0094] The five items i, ii, iii, iv, and v in the first list are ordered from highest to lowest priority. That is, item i has the highest priority, item ii has a lower priority than item i, and so on, with item v having the lowest priority.

[0095] Referring to Figure 4, the processing of the PLMN selection mechanism is illustrated by example, specifically including:

[0096] Step 401: Power on the terminal. After powering on, the terminal can detect whether a SIM card is set. If a SIM card is set, proceed to step 402; otherwise, proceed to step 402 only after the terminal has a SIM card set (SIM available).

[0097] Step 402: The terminal determines whether RPLMN exists. If it exists, proceed to step 403; otherwise, proceed to step 410. Here, the terminal determining whether RPLMN exists can mean whether the terminal has searched for RPLMN (i.e., whether the RPLMN signal has been found).

[0098] Step 403, select RPLMN on the terminal.

[0099] Step 404: The terminal attempts to register in RPLMN. If the registration in RPLMN is successful, proceed to step 405; if the registration in RPLMN fails, proceed to step 410.

[0100] Step 405: The terminal indicates the selected PLMN. This step may refer to the terminal displaying the selected PLMN locally.

[0101] After step 405 is completed, if the terminal experiences a location update and receives a location update response (such as an LR response) during the location update process, and the location update response indicates that roaming is not allowed, then step 406 is executed.

[0102] Step 406: If the PLMN where the terminal is currently located or camped loses radio coverage, proceed to step 407; or, if the terminal re-selects a user, proceed to step 409; or, if the PLMN where the terminal is currently located (on PLMN) is a VPLMN and a timeout occurs, proceed to step 415; or, the terminal directly proceeds to step 410.

[0103] Step 407: The terminal checks whether an available and allowed PLMN has been found. If not, proceed to step 408; if the terminal finds an available and allowed PLMN, proceed to step 410.

[0104] Step 408: The terminal waits until an available and allowable PLMN is found. If the available and allowable PLMN found is an RPLMN (Registered PLMN available and allowable), then step 406 is executed; if the available and allowable PLMN found is not an RPLMN, then step 410 is executed.

[0105] Step 409: The terminal temporarily moves the last selected PLMN into the first list.

[0106] Step 410: The terminal selects the first PLMN from the first list. In this step, "selecting the first PLMN from the first list" can mean that the terminal chooses the first PLMN in the first list as the first network. For example, the terminal could choose the highest-priority PLMN from the first list as the first network.

[0107] Alternatively, if the user reselects, step 410 can be executed directly.

[0108] Step 411: The terminal attempts to register in the selected PLMN. If the registration is successful, proceed to step 405. If the registration fails and there are no other PLMNs in the first list, proceed to step 412. If the registration fails and there are other PLMNs in the list, proceed to step 414.

[0109] Step 412: The terminal determines whether an available and allowable PLMN exists. If it does, proceed to step 413; otherwise, select one of RPLMN, HPLMN, or EHPLMN (if no RPLMN exists), and then proceed to step 408. Selecting one of RPLMN, HPLMN, or EHPLMN may include: if an RPLMN exists, select it; if no RPLMN exists, the terminal selects either HPLMN or EHPLMN.

[0110] Step 413: The terminal selects the first available and allowable PLMN in the first list, and then executes step 405.

[0111] The first PLMN selected from the available and accessible PLMNs in the first list can be: the PLMN with the highest priority that has not been attempted to register, is available, and allows access in the first list.

[0112] Step 414: The terminal selects the next PLMN from the first list and then executes step 411. In this step, the next PLMN may refer to the first PLMN in the first list that has not been attempted to register and has the highest priority.

[0113] Step 415: The terminal searches for a higher priority PLMN.

[0114] Step 416: The terminal performs a background search for the PLMN. If no higher-priority PLMN is found, proceed to step 406; if a higher-priority PLMN is found, proceed to step 410.

[0115] Furthermore, the terminal selecting a second optional network based on the network selection mechanism can mean that the terminal determines the priority order of one or more searched optional networks based on the PLMN selection mechanism, and selects the second optional network from the one or more optional networks based on the priority order. Here, any searched optional network can also be referred to as any searched network. In this embodiment, one or more optional networks can refer to one or more optional networks used to select the second optional network. In the relevant embodiments below that involve selecting a second optional network from one or more optional networks, one or more optional networks can be referred to as one or more optional networks used to select the second optional network, and this will not be explained again below.

[0116] After the terminal selects the second optional network based on the network selection mechanism, it needs to determine whether the second optional network matches the first information. Only if the second optional network matches the first information will the terminal use the second optional network as the second network.

[0117] After selecting a second network based on the first information, the terminal initiates registration with the second network (for example, by sending a registration request to the second network). Further, after the terminal initiates registration with the second network, the process includes: if the terminal successfully registers with the second network, the terminal establishes the second connection on the second network. This embodiment does not limit the specific process of the terminal establishing the second connection.

[0118] Additionally, it may include: if the terminal does not match the first information in the second optional network and / or fails to register in the second network, the terminal may reselect the second optional network based on the network selection mechanism.

[0119] Specifically, the RAT corresponding to the second optional network matches one or more RATs corresponding to the second connection included in the first information; the RAT corresponding to the second optional network matches the highest priority RAT among the one or more RATs corresponding to the second connection included in the first information; the second optional network matches one or more networks corresponding to the second connection included in the first information; the second optional network matches the highest priority network among the one or more networks corresponding to the second connection included in the first information; the second optional network and the RAT corresponding to the second optional network match one or more combined information among the one or more combined information among the one or more combined information among the one or more combined information among the one or more combined information among the one or more combined information among the first information.

[0120] Optionally, the first information includes one or more RATs corresponding to the second connection. The determination of whether the second optional network matches the first information can be as follows: determine whether the RAT corresponding to the second optional network is among the one or more RATs corresponding to the second connection included in the first information; if so, the second optional network matches the first information; otherwise, the second optional network does not match the first information.

[0121] The RAT corresponding to the second optional network may include the RAT (or RAT type) of each cell in one or more cells of the second optional network. Determining whether the RAT corresponding to the second optional network is among the one or more RATs corresponding to the second connection included in the first information may refer to determining whether there exists any cell in the one or more cells of the second optional network whose RAT is the same as any one of the one or more RATs corresponding to the second connection included in the first information.

[0122] Optionally, the first information includes one or more RATs corresponding to the second connection and the priority of the one or more RATs corresponding to the second connection. This priority may be explicitly indicated or implicitly indicated.

[0123] The determination of whether the second optional network matches the first information can be made by determining whether the RAT corresponding to the second optional network matches the highest priority RAT among one or more RATs corresponding to the second connection contained in the first information. If so, the second optional network matches the first information; otherwise, the second optional network does not match the first information.

[0124] Specifically, determining whether the RAT corresponding to the second optional network matches the highest priority RAT among one or more RATs corresponding to the second connection contained in the first information can refer to determining whether there is any RAT in one or more cells of the second optional network that is the same as the highest priority RAT among one or more RATs corresponding to the second connection contained in the first information.

[0125] Optionally, the first information includes one or more networks corresponding to the second connection. The determination of whether the second optional network matches the first information can be as follows: determine whether the second optional network is among the one or more networks corresponding to the second connection included in the first information; if it is, then the second optional network matches the first information; otherwise, the second optional network does not match the first information.

[0126] Optionally, the first information includes one or more networks corresponding to the second connection and the priority of the one or more networks corresponding to the second connection (the priority may be explicitly indicated or implicitly indicated). The determination of whether the second optional network matches the first information can be made by determining whether the second optional network matches the network with the highest priority among the one or more networks corresponding to the second connection included in the first information. If so, the second optional network matches the first information; otherwise, the second optional network does not match the first information.

[0127] Optionally, the first information includes one or more combination information corresponding to the second connection. The method for determining whether the second optional network matches the first information can be: determining whether the second optional network and its corresponding RAT are included in any combination information corresponding to the second connection contained in the first information; if so, the second optional network matches the first information; otherwise, the second optional network does not match the first information.

[0128] Optionally, the first information includes one or more combination information corresponding to the second connection and the priority of the one or more combination information corresponding to the second connection (the priority may be an explicit or implicit indication). The determination of whether the second optional network matches the first information can be made by determining whether the second optional network and its corresponding RAT match the highest priority combination information corresponding to the second connection included in the first information. If so, the second optional network matches the first information; otherwise, the second optional network does not match the first information.

[0129] For example, the process of a terminal selecting a second network based on the first information can be executed jointly based on the terminal behavior of network selection (PLMN selection) specified in the relevant protocol and the first information. For instance, when the terminal (i.e., the MS) powers on, the terminal prioritizes selecting an RPLMN (i.e., selecting an RPLMN as the second optional network). If the RPLMN does not match the first information, or the RPLMN cannot be selected (i.e., registration fails at the RPLMN), the terminal selects another PLMN as the second optional network. If the selected second optional network matches the first information and registration is successful, then the second optional network is adopted as the second network. The process of the terminal selecting another PLMN as the second optional network can be executed by the terminal according to the priority order of the items included in the first list, according to symbols i, ii, iii, iv, v (allowed), which will not be elaborated here.

[0130] Referring to Figure 4 in the aforementioned example, the process of the terminal selecting the second network based on the first information can be improved by adding some steps to the flow provided in Figure 4, specifically including:

[0131] In step 403, the terminal selects RPLMN. In this embodiment, this may mean that the terminal selects RPLMN as the second optional network.

[0132] After completing step 403, and before executing step 404 and before executing step 410, the terminal performs the following additional processing: The terminal determines whether RPLMN (i.e., the second optional network) matches the first information. If RPLMN (i.e., the second optional network) matches the first information, the second optional network is used as the second network, and step 404 is executed; if RPLMN does not match the first information, step 410 is executed.

[0133] In step 410, the terminal selects the first PLMN from the first list. In this embodiment, it means that the terminal selects the first PLMN from the first list and uses the first PLMN as the second optional network.

[0134] In step 414, the terminal selects the next PLMN from the first list. In this embodiment, it means that the terminal selects the next PLMN from the first list and uses the next PLMN as the second optional network.

[0135] After completing step 410 or step 414, the following process is added: The terminal determines whether the selected PLMN (i.e., the second optional network) matches the first information. If the selected PLMN matches the first information, the selected PLMN is used as the second network and step 411 is executed; otherwise, step 414 is executed.

[0136] Apart from the steps mentioned above, the explanations for the remaining steps are the same as those in the example section corresponding to Figure 4, so they will not be repeated here.

[0137] In one embodiment, the terminal selecting a second network based on first information may include one of the following: the terminal selects a second RAT from one or more RATs corresponding to the second connection included in the first information, and uses the network corresponding to the second RAT as the second network; the terminal selects the highest priority RAT from one or more RATs corresponding to the second connection included in the first information, and uses the network corresponding to the highest priority RAT as the second network; the terminal selects the second network from one or more networks corresponding to the second connection included in the first information; the terminal selects the highest priority network from one or more networks corresponding to the second connection included in the first information as the second network; the terminal selects second combination information from one or more combination information corresponding to the second connection included in the first information, and uses the network contained in the second combination information as the second network; the terminal selects the highest priority combination information from one or more combination information corresponding to the second connection included in the first information, and uses the network contained in the highest priority combination information as the second network.

[0138] After selecting the second network based on the first information, registration can be initiated on the second network. After the terminal initiates registration with the second network, the process may further include: if the terminal successfully registers on the second network, establishing the second connection on the second network. This embodiment does not limit the specific process of the terminal establishing the second connection.

[0139] Additionally, the process may include: if the terminal fails to register with the second network, the terminal reselects the second network based on the first information. The process of the terminal reselecting the second network based on the first information is similar to the initial selection of the second network based on the first information.

[0140] Optionally, the first information includes one or more RATs corresponding to the second connection. The terminal selecting a second RAT from the one or more RATs corresponding to the second connection included in the first information can be: the terminal selecting a RAT that has not been attempted to register from the one or more RATs corresponding to the second connection included in the first information as the second RAT.

[0141] Specifically, when the terminal first selects a second network based on the first information, none of the networks corresponding to one or more RATs associated with the first connection included in the first information have attempted registration. Therefore, the terminal randomly selects any one of the RATs associated with the second connection included in the first information as the second RAT. When the terminal reselects the second network based on the first information, since at least some of the RATs may have already attempted registration and failed, the terminal arbitrarily or randomly selects one RAT from all the RATs associated with networks that have not attempted registration, as the second RAT.

[0142] Furthermore, using the network corresponding to the second RAT as the second network can mean: if the terminal finds a network corresponding to the second RAT, that network is used as the second network; or, if the terminal finds multiple networks corresponding to the second RAT, the network with the strongest signal among the multiple networks is used as the second network.

[0143] Optionally, the first information includes one or more RATs corresponding to the second connection and the priority of the one or more RATs corresponding to the second connection. This priority may be explicitly indicated or implicitly indicated.

[0144] The terminal selecting the highest priority RAT from one or more RATs corresponding to the second connection included in the first information can mean that the terminal selects the highest priority RAT that has not been attempted to register from one or more RATs corresponding to the second connection included in the first information.

[0145] Specifically, when the terminal initially selects the second network based on the first information, none of the networks corresponding to one or more RATs associated with the second connection included in the first information have attempted registration. Therefore, the terminal selects the highest priority RAT from all RATs associated with the second connection included in the first information. However, when the terminal reselects the second network based on the first information, since at least some RATs may have already attempted registration and failed, the terminal selects the highest priority RAT from all RATs associated with networks that have not attempted registration, as included in all RATs associated with the second connection included in the first information.

[0146] It should be noted that selecting the highest priority RAT can include: when there are multiple highest priority RATs, arbitrarily selecting one from the multiple RATs as the highest priority RAT.

[0147] Furthermore, using the network corresponding to the highest priority RAT as the second network can be: if the terminal finds a network corresponding to the highest priority RAT, then that network is used as the second network; or, if the terminal finds multiple networks corresponding to the highest priority RAT, then the network with the strongest signal among the multiple networks is used as the second network.

[0148] Optionally, the first information includes one or more networks corresponding to the second connection. The terminal selecting the second network from the one or more networks corresponding to the second connection included in the first information can be done by randomly selecting a network that has not been previously registered as the second network from the one or more networks corresponding to the second connection included in the first information.

[0149] Specifically, when the terminal first selects a second network based on the first information, none of the one or more networks corresponding to the second connection included in the first information have attempted registration. Therefore, the terminal randomly selects any one of the networks corresponding to the second connection included in the first information as the second network. When the terminal reselects the second network based on the first information, since at least some networks may have attempted registration and failed, the terminal arbitrarily or randomly selects one network from all the networks corresponding to the second connection included in the first information that have not attempted registration as the second network.

[0150] Optionally, the first information includes one or more networks corresponding to the second connection and the priority of the one or more networks corresponding to the second connection. This priority may be explicitly indicated or implicitly indicated.

[0151] The terminal selecting the highest priority network from one or more networks corresponding to the second connection included in the first information as the second network can mean that the terminal selects the network that has not been attempted to register and has the highest priority from one or more networks corresponding to the second connection included in the first information as the second network.

[0152] Specifically, when the terminal initially selects a second network based on the first information, none of the networks corresponding to one or more RATs associated with the second connection included in the first information have attempted registration. Therefore, the terminal selects the network with the highest priority from all networks corresponding to the second connection included in the first information as the second network. When the terminal reselects the second network based on the first information, since at least some networks may have attempted registration and failed, the terminal selects the network with the highest priority from among the networks that have not attempted registration from all networks corresponding to the second connection included in the first information. It should be noted that selecting the network with the highest priority as the second network may include: if there are multiple networks with the highest priority, arbitrarily selecting one as the second network; or, if there is only one network with the highest priority, selecting that network as the second network.

[0153] Optionally, the first information includes one or more combinations of information corresponding to the second connection. The terminal selecting the second combination of information from the one or more combinations of information corresponding to the second connection included in the first information can be: the terminal randomly selects combination information containing networks that have not been attempted to be registered with as the second combination of information from the one or more combinations of information corresponding to the second connection included in the first information.

[0154] Specifically, when the terminal first selects a second network based on the first information, none of the networks included in one or more combinations of information corresponding to the second connection contained in the first information have attempted to register. Therefore, the terminal randomly selects any one of the combinations of information corresponding to the second connection contained in the first information as the second combination of information. When the terminal reselects a second optional network based on the first information, since at least some networks may have attempted to register and failed, the terminal arbitrarily or randomly selects one combination of information from the combinations of information containing networks that have not attempted to register, as the second combination of information, from all the combinations of information corresponding to the second connection contained in the first information.

[0155] Optionally, the first information includes one or more combined information corresponding to the second connection, and the priority of the one or more combined information corresponding to the second connection. This priority may be an explicit indication or an implicit indication.

[0156] The terminal selecting the highest priority combination information from one or more combination information corresponding to the second connection included in the first information may refer to the terminal selecting the combination information containing the network that has not been tried to register and has the highest priority from one or more combination information corresponding to the second connection included in the first information as the second combination information.

[0157] Specifically, when the terminal initially selects a second network based on the first information, none of the networks included in one or more combinations of information corresponding to the second connection contained in the first information have attempted registration. Therefore, the terminal selects the highest priority combination from all combinations of information corresponding to the second connection contained in the first information as the second combination. When the terminal reselects the second network based on the first information, since at least some networks may have attempted registration and failed, the terminal selects the highest priority combination from all combinations of information corresponding to the second connection contained in the first information that includes networks that have not attempted registration as the second combination. It should be noted that selecting the highest priority combination as the second combination may include: if there are multiple combinations of information with the highest priority, arbitrarily selecting one from these combinations as the second combination; or, if there is only one combination of information with the highest priority, using that combination as the second combination.

[0158] In one embodiment, the terminal selecting a second network based on the first information may include: the terminal selecting the second network based on the first network and the first information.

[0159] The first information includes one of the following: a first association relationship between one or more RATs corresponding to the first connection and one or more RATs corresponding to the second connection; a second association relationship between one or more networks corresponding to the first connection and one or more networks corresponding to the second connection; and a third association relationship between one or more combined information corresponding to the first connection and one or more combined information corresponding to the second connection. Wherein, the first connection is established by the terminal under a first network.

[0160] Furthermore, in addition to at least one of the above-mentioned associations, the first information may also include at least one of the following: one or more RATs corresponding to the first connection, the priority of one or more RATs corresponding to the first connection, one or more networks corresponding to the first connection, the priority of one or more networks corresponding to the first connection, one or more combination information corresponding to the first connection, the priority of one or more combination information corresponding to the first connection, one or more RATs corresponding to the second connection, the priority of one or more RATs corresponding to the second connection, one or more networks corresponding to the second connection, the priority of one or more networks corresponding to the second connection, one or more combination information corresponding to the second connection, and the priority of one or more combination information corresponding to the second connection.

[0161] The terminal selects the second network based on the first network and the first information, including one of the following: the terminal determines the second RAT corresponding to the second connection based on the RAT corresponding to the first network and the first association relationship contained in the first information, and uses the network corresponding to the second RAT as the second network, wherein the RAT corresponding to the first network is one of one or more RATs corresponding to the first connection; the terminal determines the second network based on the first network and the second association relationship contained in the first information, wherein the first network is one of one or more networks corresponding to the first connection; the terminal determines the second combination information corresponding to the second connection associated with the first network and its corresponding RAT based on the first network and its corresponding RAT and the third association relationship contained in the first information, and uses the network contained in the second combination information as the second network, wherein the first network and its corresponding RAT are one of one or more combination information corresponding to the first connection.

[0162] In one example, the first information may include one or more RATs corresponding to the first connection, one or more RATs corresponding to the second connection, and a first association relationship. The number of RATs corresponding to the second connection may be the same as or different from the number of RATs corresponding to the first connection. In this example, the terminal determines the second RAT corresponding to the second connection based on the RATs corresponding to the first network and the first association relationship contained in the first information, and designates the network corresponding to the second RAT as the second network.

[0163] In the first association, any RAT in the first connection may be associated with one or more RATs in the second connection, where different RATs corresponding to the first connection are associated with different RATs in the second connection. For example, the first connection may correspond to 3 RATs, namely RAT-1, RAT-2, and RAT-3; the second connection may correspond to 4 RATs, namely RAT-a, RAT-b, RAT-c, and RAT-d; the first association includes: RAT-1 corresponding to RAT-a in the second connection, RAT-2 corresponding to RAT-b and RAT-c in the second connection, and RAT-3 corresponding to RAT-d in the second connection.

[0164] Alternatively, in the first association, one or more RATs of the first connection are associated with one RAT of the second connection, wherein different RATs corresponding to the second connection are associated with different RATs of the first connection;

[0165] Alternatively, in the first association, multiple RATs of the first connection are associated with multiple RATs of the second connection. For example, the first connection can correspond to 3 RATs, namely RAT-1, RAT-2, and RAT-3; the second connection can correspond to 4 RATs, namely RAT-a, RAT-b, RAT-c, and RAT-d; the first association includes: RAT-1 and RAT-2 corresponding to RAT-b and RAT-c corresponding to the second connection, and RAT-3 corresponding to RAT-d corresponding to the second connection.

[0166] It should be noted that the first information may implicitly or explicitly indicate the first association relationship.

[0167] For example, the first information implicitly indicates the first association. Suppose that the first information contains two side-by-side columns in a list format. The first column of the two columns is divided into multiple rows from top to bottom, setting one or more RATs corresponding to the first connection. The second column of the two columns is divided into multiple rows from top to bottom, setting one or more RATs corresponding to the second connection. The RATs corresponding to the first connection and the RATs corresponding to the second connection that are located in the same row in the two columns have an association relationship.

[0168] For example, the first association can be explicitly indicated in the first information. Suppose the first information includes one or more RATs corresponding to the first connection, an association indicator parameter can be added directly after each RAT corresponding to the first connection to directly describe the RAT corresponding to the second connection associated with that RAT. For instance, if RAT-1 corresponding to the first connection is associated with RAT-a corresponding to the second connection, the first information can directly include the association indicator parameter for RAT-1 corresponding to the first connection, which directly describes the association between RAT-1 and RAT-a corresponding to the second connection.

[0169] Optionally, the first information includes: one or more RATs corresponding to the first connection and their priorities, one or more RATs corresponding to the second connection, and a first association relationship. The priority may be an implicit or explicit indication, and its related description is the same as in the foregoing embodiments, and will not be repeated below.

[0170] The description of the quantitative relationship between the RAT corresponding to the first connection and the RAT corresponding to the associated second connection is the same as in the previous example and will not be repeated.

[0171] The priorities of each RAT corresponding to the second connection are the same as the priorities of the RATs corresponding to the associated first connection. That is, in the first association, a RAT (which can be one or more) of a certain priority corresponding to the first connection may be associated with one or more RATs corresponding to the second connection. In this case, the priorities of the one or more RATs corresponding to the second connection are the same as those of the RATs corresponding to the associated first connection. For example, the first connection can correspond to 3 RATs: the highest priority RAT-1, the medium priority RAT-2, and the lowest priority RAT-3; the second connection can correspond to 4 RATs: RAT-a, RAT-b, RAT-c, and RAT-d. The first association includes: RAT-1 corresponding to RAT-a of the second connection, which is also the highest priority; RAT-2 corresponding to RAT-b and RAT-c of the second connection, both of which are medium priority; and RAT-3 corresponding to RAT-d of the second connection, which is the lowest priority.

[0172] The RAT corresponding to the first network is one of one or more RATs corresponding to the first connection. The terminal determines the second RAT corresponding to the second connection based on the RAT corresponding to the first network and the first association relationship contained in the first information. This can be done by the terminal using the RAT corresponding to the first network as the first RAT corresponding to the first connection, determining one or more RATs corresponding to the second connection associated with the first RAT from the first association relationship contained in the first information, and arbitrarily selecting one RAT from the one or more RATs corresponding to the second connection associated with the first RAT as the second RAT.

[0173] Using the network corresponding to the second RAT as the second network can mean: if the terminal finds a network corresponding to the second RAT, that network is used as the second network; or, if the terminal finds multiple networks corresponding to the second RAT, the network with the strongest signal among the multiple networks is used as the second network.

[0174] In one example, the first information may include one or more networks corresponding to the first connection, one or more networks corresponding to the second connection, and a second association relationship. In this example, the terminal determines the second network based on the first network and the second association relationship included in the first information.

[0175] The number of networks corresponding to the second connection may be the same as or different from the number of networks corresponding to the first connection. The description of the quantitative relationship between the networks corresponding to the first connection and the networks corresponding to the associated second connection in the second association is similar to the description of the quantitative relationship between the RATs corresponding to the first connection and the RATs corresponding to the associated second connection in the aforementioned example of the first association, and therefore will not be repeated. This second association can also be an implicit or explicit indication. The description of how this second association is indicated in the first information is similar to that of the aforementioned first association, and therefore will not be repeated.

[0176] Optionally, the first information includes: one or more networks corresponding to the first connection and their priorities, one or more networks corresponding to the second connection, and a second association relationship. The priorities of each network corresponding to the second connection are the same as the priorities of the networks corresponding to the first connection. That is, in the second association relationship, a network (which can be one or more) with a certain priority corresponding to the first connection may be associated with one or more networks corresponding to the second connection. In this case, the priorities of the one or more networks corresponding to the second connection are the same as the priorities of the networks corresponding to the first connection.

[0177] The first network is one of one or more networks corresponding to the first connection. The terminal determines the second optional network based on the first network and the second association relationship contained in the first information. This can be done by the terminal determining one or more networks corresponding to the second connection associated with the first network from the second association relationship contained in the first information, and selecting one network from the one or more networks corresponding to the second connection associated with the first network as the second network.

[0178] In one example, the first information may include one or more combination information corresponding to the first connection, one or more combination information corresponding to the second connection, and a third association relationship. Based on the first network and its corresponding RAT, and the third association relationship contained in the first information, the terminal determines the second combination information corresponding to the second connection associated with the first network and its corresponding RAT, and selects the network contained in the second combination information as the second network.

[0179] The quantity of combined information corresponding to the second connection and the combined information of the network corresponding to the first connection may be the same as or different. The explanation of the quantitative relationship between the combined information corresponding to the first connection and the combined information corresponding to the associated second connection in the third association is similar to the explanation of the quantitative relationship between the RAT corresponding to the first connection and the RAT corresponding to the associated second connection in the aforementioned example of the first association, and therefore will not be repeated. This third association can also be an implicit or explicit indication. The explanation of the indication method of this third association in the first information is similar to that of the aforementioned first association, and therefore will not be repeated.

[0180] Optionally, the first information includes: one or more combined information corresponding to the first connection and their priority, one or more combined information corresponding to the second connection, and a third association relationship. The description of the quantitative relationship between the combined information corresponding to the first connection and the combined information corresponding to the associated second connection in the third association relationship is the same as in the previous example and will not be repeated here.

[0181] In this example, the priority of each combination of information corresponding to the second connection is the same as the priority of the combination of information corresponding to the first connection it is associated with. That is, in the third association, a combination of information (which can be one or more) of a certain priority corresponding to the first connection may be associated with one or more combination of information corresponding to the second connection. In this case, the priority of the one or more combination of information corresponding to the second connection is the same as the priority of the combination of information corresponding to the first connection it is associated with.

[0182] The first network and its corresponding RAT are one of one or more combination information corresponding to the first connection. The terminal determines the second combination information corresponding to the second connection associated with the first network and its corresponding RAT based on the first network and its corresponding RAT and the third association relationship contained in the first information. This may include: the terminal taking the first network and its corresponding RAT as the first combination information corresponding to the first connection, determining one or more combination information corresponding to the second connection associated with the first combination information from the third association relationship contained in the first information; and arbitrarily selecting one combination information as the second combination information from the one or more combination information corresponding to the second connection associated with the first combination information.

[0183] In this embodiment, after selecting the second network based on the first network and the first information, the terminal can initiate registration with the second network. After the terminal initiates registration with the second network, the method further includes: if the terminal successfully registers with the second network, establishing the second connection on the second network.

[0184] Alternatively, after the terminal initiates registration with the second network, it may also include one of the following: if the terminal fails to register with the second network, the terminal reselects the first network; or if the terminal fails to register with the second network, the multi-connection function is cancelled.

[0185] Optionally, if the terminal fails to register on the second network, the terminal may reselect the first network based on the first information. The specific method by which the terminal reselects the first network based on the first information is not limited here.

[0186] Optionally, if the terminal fails to register on the second optional network, it can cancel the multi-connection function.

[0187] This situation also includes: when the terminal cancels the multi-connection function, it sends a multi-connection disable instruction, wherein the multi-connection disable instruction is used to instruct the terminal to disable the multi-connection function.

[0188] Specifically, sending a multi-connection disable instruction can be achieved by the terminal sending a multi-connection disable instruction to the first core network device. Correspondingly, after sending a multi-connection enable instruction, the first core network device may further include receiving a multi-connection disable instruction from the terminal, wherein the multi-connection disable instruction is used to instruct the terminal to disable the multi-connection function.

[0189] The multi-connection disable instruction can be carried in a third NAS message, and the specific type of the third NAS message is not limited in this embodiment. The multi-connection disable instruction can also be alternatively referred to as the "disable DualSteer" instruction. That is, if the terminal cannot complete network selection (select the second network) based on the "first information", the terminal disables the DualSteer function and reports "Disabling DualSteer" to the network side.

[0190] It should be noted that the above is only an illustrative example. In actual processing, the handling of the terminal after registration failure on the second optional network may include other possibilities. In some possible examples, after the terminal selects the second network based on the first network and the first information, it may further include: if the terminal fails to register on the second network, the terminal may register on the second network once or multiple times.

[0191] For example, if the terminal fails to register on the second network, it can maintain the first connection and re-initiate a registration request to the second network (i.e., the terminal attempts to register on the second optional network again). This registration request can be initiated after a first delay following the registration failure on the second network. This first delay can be configured according to actual circumstances and is not limited here.

[0192] For example, if the terminal fails to register on the second network, it can maintain the first connection and periodically initiate registration requests to the second network (i.e., the terminal periodically attempts to register on the second network). The duration of this periodic registration request can be configured according to actual conditions and is not limited here. In other words, the terminal can maintain the first connection on the first network while attempting to register on the second network once or multiple times until registration is completed on the second network, and then establish a connection on the second network; or, the terminal can maintain the first connection on the first network while attempting to register on the second network once or multiple times until the number of attempts reaches a preset threshold, at which point the process ends, the first network is reselected, or a multi-connection disable indication is sent. This preset threshold can be configured according to actual conditions and is not limited.

[0193] In some possible implementations, the terminal first selects a first network, establishes a first connection on the first network, and then selects a second network.

[0194] It should be noted that before the terminal selects a second network, it may have already established a connection under a single network. In this case, the first network can be the only network currently registered by the terminal, and the first connection is the connection established under the first network. Alternatively, before the terminal selects a second network, it may have already established a connection under each of multiple networks. In this case, the first network can be any one of the multiple networks.

[0195] Furthermore, before the terminal selects the second network, the second network may include any network that the terminal has not registered and has not established a connection with after establishing the first connection under the first network.

[0196] In some embodiments, before establishing a first connection under a first network, the terminal may select a first network.

[0197] The terminal selects the first network, which may include: the terminal selects the first network based on a network selection mechanism.

[0198] The network selection mechanism may refer to the PLMN selection mechanism. The relevant descriptions of this PLMN selection mechanism are the same as in the aforementioned embodiments and will not be repeated. Specifically, the terminal selecting a first network based on the network selection mechanism can mean that the terminal selects a first network from one or more searched optional networks based on the PLMN selection mechanism.

[0199] Additionally, after selecting a first network from one or more available networks based on the PLMN selection mechanism, the terminal initiates registration with the first network. After the terminal initiates registration with the first network (e.g., sends a registration request to the first network), one of the following may also be included: if the terminal successfully registers with the first network, it establishes a first connection on the first network; if the terminal fails to register with the first network, and the terminal determines that it cannot select a first network, it reselects a first network from one or more available networks based on the PLMN selection mechanism. The specific process of the terminal establishing a first connection on the first network is not limited in this embodiment.

[0200] The terminal reselecting a first network from one or more searched optional networks based on the PLMN selection mechanism can mean that the terminal reselects a first network from one or more searched optional networks that it has not currently attempted to register with. The difference between the process of the terminal reselecting the first network and the process of the terminal initially selecting the first network is that the terminal can exclude some optional networks that have already been attempted to register with, and only select the first network from the searched optional networks that it has not yet attempted to register with. The specific method of the terminal reselecting the first network is the same as that of the initial selection of the first network, and will not be elaborated further.

[0201] Taking one or more searched optional networks, including RPLMNs and one or more other PLMNs (or combinations of other PLMNs and RATs) in the first list, as an example, after initially selecting RPLMN as the first network, the terminal initiates registration with RPLMN. If the terminal fails to register with RPLMN, the priority order of other PLMNs (such as other PLMNs in the first list (or combinations of other PLMNs and RATs)) that have been searched and have not yet been registered with is determined based on the PLMN selection mechanism. Based on the priority order of other PLMNs, one other PLMN is selected as the first network, and registration is initiated on the first network. This process continues until the first network is selected and registration is successful, at which point the first connection is established on the first network. The specific processing of the terminal selecting the first network based on the PLMN selection mechanism is the same as in Figure 4, and therefore will not be elaborated further.

[0202] In some possible embodiments, before the terminal establishes the first connection under the first network, it may further include: the terminal selecting the first network based on first information.

[0203] In this embodiment, the first information includes at least one of the following: one or more RATs corresponding to the first connection, the priority of one or more RATs corresponding to the first connection, one or more networks corresponding to the first connection, the priority of one or more networks corresponding to the first connection, one or more combination information corresponding to the first connection, and the priority of one or more combination information corresponding to the first connection, wherein the combination information includes networks and RATs. The first connection is established by the terminal under the first network.

[0204] In this embodiment, the descriptions of the RAT corresponding to the first connection, the priority of the RAT corresponding to the first connection, the network corresponding to the first connection, the priority of the network corresponding to the first connection, the combination information corresponding to the first connection, and the priority of the combination information corresponding to the first connection are similar to the descriptions of the second connection in the previous embodiment, so they will not be repeated.

[0205] In one embodiment, the terminal selecting a first network based on first information may include: the terminal selecting a first optional network based on a network selection mechanism; and the terminal using the first optional network as the first network if the first optional network matches the first information.

[0206] After selecting a first network based on the first information, the terminal can initiate registration with the first network. Following the terminal's registration with the first network, the process further includes: if the terminal successfully registers with the first network, establishing the first connection on the first network.

[0207] Additionally, it may include: if the terminal does not match the first optional network with the first information, and / or if registration fails on the first network, the terminal reselects the first optional network based on the network selection mechanism.

[0208] In this embodiment, the specific processing procedure for establishing the first connection by the terminal is not limited.

[0209] The network selection mechanism can refer to the PLMN selection mechanism. Specifically, the process of the terminal selecting a first optional network based on this mechanism can be as follows: the terminal selects a first optional network from one or more searched optional networks based on the PLMN selection mechanism. The specific description of the terminal selecting the first optional network from one or more searched optional networks based on the PLMN selection mechanism is the same as in the previous embodiment. The difference is that in this embodiment, the selected network is the first optional network, and after selecting the first optional network, it is first determined whether the first optional network matches the first information. Therefore, the specific process of selecting the first optional network will not be elaborated upon.

[0210] The matching of the first optional network with the first information includes one of the following: the RAT corresponding to the first optional network matches one of the one or more RATs corresponding to the first connection included in the first information; the RAT corresponding to the first optional network matches the highest priority RAT among the one or more RATs corresponding to the first connection included in the first information; the first optional network matches one of the one or more networks corresponding to the first connection included in the first information; the first optional network matches the highest priority network among the one or more networks corresponding to the first connection included in the first information; the first optional network and the RAT corresponding to the first optional network match one of the one or more combined information corresponding to the first connection included in the first information; the first optional network and the RAT corresponding to the first optional network match the highest priority combined information among the one or more combined information corresponding to the first connection included in the first information.

[0211] The specific description of the method for determining whether the first optional network matches the first information is similar to the method for determining whether the second optional network matches the second information in the previous embodiment. The only difference is that in this embodiment, the matching is performed using the RAT corresponding to the first connection, the network corresponding to the first connection, or the combined information corresponding to the first connection. Therefore, the description will not be repeated.

[0212] The process of the terminal reselecting the first optional network is similar to the process of the terminal reselecting the second optional network in the previous embodiment. The specific method of the terminal selecting the first optional network for the first time is similar to the process of the terminal selecting the second optional network for the first time in the previous embodiment, and will not be described again.

[0213] Referring to Figure 4 in the aforementioned example, the process of the terminal selecting the first network based on the first information can be improved by adding some steps to the flow provided in Figure 4, specifically including:

[0214] In step 403, the terminal selects RPLMN. In this embodiment, this may mean that the terminal selects RPLMN as the first optional network.

[0215] After completing step 403, and before executing step 404 or before executing step 410, the terminal performs the following processing: The terminal determines whether RPLMN (i.e., the first optional network) matches the first information. If RPLMN (i.e., the first optional network) matches the first information, then RPLMN is used as the first network and step 404 is executed; if RPLMN does not match the first information, then step 410 is executed.

[0216] In step 410, the terminal selects the first PLMN from the first list. In this embodiment, it means that the terminal selects the first PLMN from the first list and uses the first PLMN as the first optional network.

[0217] In step 414, the terminal selects the next PLMN from the first list. In this embodiment, it means that the terminal selects the next PLMN from the first list and uses the next PLMN as the first optional network.

[0218] After completing step 410, or after completing step 414, the following process is added: The terminal determines whether the selected PLMN (i.e., the first optional network) matches the first information. If the selected PLMN matches the first information, the selected PLMN is used as the first network and step 411 is executed; otherwise, step 414 is executed.

[0219] Apart from the steps mentioned above, the explanations for the remaining steps are the same as those in the example section corresponding to Figure 4, so they will not be repeated here.

[0220] In one embodiment, the terminal selects a first network based on the first information, including one of the following: the terminal selects a first RAT from one or more RATs corresponding to the first connection included in the first information, and uses the network corresponding to the first RAT as the first network; the terminal selects the highest priority RAT from one or more RATs corresponding to the first connection included in the first information, and uses the network corresponding to the highest priority RAT as the first network; the terminal selects the first network from one or more networks corresponding to the first connection included in the first information; the terminal selects the highest priority network from one or more networks corresponding to the first connection included in the first information, and uses the network contained in the first combination information as the first network; the terminal selects the highest priority combination information from one or more combination information corresponding to the first connection included in the first information, and uses the network contained in the first combination information as the first network.

[0221] After the terminal selects the first network based on the first information, it may include: the terminal initiating registration with the first network.

[0222] After the terminal initiates registration with the first network, the process may further include: if the terminal successfully registers with the first network, the terminal establishes a first connection with the first network. This embodiment does not limit the specific process of the terminal establishing the first connection.

[0223] In addition, after the terminal initiates registration with the first network, the process may further include: if the terminal fails to register with the first network, the terminal reselects the first network based on the first information.

[0224] Unlike the previous embodiments, in this embodiment, the terminal no longer needs to combine the network selection mechanism (i.e., PLMN selection mechanism) in the related technology to select the first network, but directly selects the first network based on the first information.

[0225] The specific description of the terminal selecting the first network based on the first information in this embodiment is similar to the specific description of the terminal selecting the second network based on the first information in the previous embodiment. The only difference is that this embodiment uses the RAT corresponding to the first connection, or the network corresponding to the first connection, or a combination of information corresponding to the first connection for processing. Therefore, the description will not be repeated.

[0226] It should be noted that, in this embodiment, without the network selection mechanism, the description of the terminal initially selecting the first network based on the first information, or the terminal reselecting the first network based on the first information, is similar to the description of the terminal initially selecting the second network based on the first information, or the terminal reselecting the second network based on the first information, in the aforementioned embodiment without the network selection mechanism. Therefore, it will not be repeated.

[0227] The foregoing provisions of this application provide various embodiments for a terminal to select a first network and various embodiments for a terminal to select a second network based on first information, which can be used in combination. The following examples illustrate these embodiments:

[0228] Method 1: Select the first network according to the existing network selection mechanism, and then establish the first connection in the first network. Select the second network based on the RAT corresponding to the second connection in the first information, and then establish the second connection.

[0229] The first information of Method-1 is illustrated in Table 1 as an example:

[0230] Table 1

[0231] The first information shown in Table 1 only includes the RAT list corresponding to the second connection (i.e., one or more RATs, namely RAT-a, RAT-b, RAT-c, and RAT-d). RAT-a, RAT-b, RAT-c, and RAT-d may not have priority. Alternatively, RAT-a, RAT-b, RAT-c, and RAT-d may have priority. In this example, the priority of RAT-a, RAT-b, RAT-c, and RAT-d can be implicitly indicated by decreasing priority from left to right, meaning RAT-a has the highest priority, RAT-b has a lower priority than RAT-a, RAT-c has a lower priority than RAT-b, and RAT-d has the lowest priority.

[0232] In Method-1, the terminal selects the first network according to the PLMN selection mechanism. After selecting the first network, it initiates registration with the first network. If the registration is successful, the terminal establishes the first connection under the first network. With the terminal establishing the first connection under the first network and enabling or activating the DualSteer function, the terminal refers to the RAT list corresponding to the second connection in Table 1 to select the second network.

[0233] In one scenario, the RAT list corresponding to the second connection contains or has priority. In this case, the mechanism for selecting the second network based on RAT can be combined with the existing PLMN-based selection mechanism. For example, based on the PLMN selection mechanism, when considering or selecting the cell of the highest priority PLMN-1 (the second optional network), its RAT is RAT-b. This RAT-b is not the highest priority RAT in Table 1. Therefore, based on the PLMN selection mechanism again, the second priority PLMN-2 (the reselected second optional network) is considered or selected. If the cell of PLMN-2 has RAT-a type and the registration process can be completed by selecting this cell, then the terminal selects PLMN-2 as the second network. If the registration process is initiated and completed on the second network, a second connection is established on the second network. Otherwise, the RAT type of the cell of the next priority PLMN is considered again based on the priority of PLMN selection in the relevant protocol, and so on. This will not be elaborated further.

[0234] In one scenario, the RAT list corresponding to the second connection may not contain or may not have priority. In this case, the mechanism for selecting the second network based on RAT can be combined with the existing PLMN selection mechanism. For example, when considering or selecting the cell of the highest priority PLMN-1 (the second optional network) based on the PLMN selection mechanism in the relevant protocol, its RAT is RAT-4, which is not in the RAT list corresponding to the second connection in Table 1. Then, based on the PLMN selection mechanism, considering or selecting the second priority PLMN-2 (the reselected second optional network), if the cell of PLMN-2 has a RAT-b type (in the RAT list corresponding to the second connection), then the second optional network (the cell under the second optional network) is selected as the second network, the registration process is initiated and completed on the second network, and the second connection is established on the second network. Otherwise, based on the PLMN selection mechanism in the relevant protocol, the RAT type of the cell of the next priority PLMN is considered, and so on, without further details.

[0235] It should be noted that the above method-1 is only an illustrative example. In actual processing, the RAT list corresponding to the second connection included in the first information can also be replaced with one or more networks corresponding to the second connection, or one or more combined information corresponding to the second connection. Regarding the case where the first information includes one or more networks corresponding to the second connection, or one or more combined information corresponding to the second connection, the specific process of selecting the second network based on the first information is the same as the aforementioned embodiment, and therefore will not be repeated.

[0236] Method 2: Select the first network based on the RAT corresponding to the first connection in the first information, and then establish the first connection; select the second network based on the RAT corresponding to the second connection in the first information, and then establish the second connection.

[0237] The first information of Method-2 is illustrated in Table 2 as an example:

[0238] Table 2

[0239] The first information shown in Table 2 includes the RAT list corresponding to the first connection (i.e., one or more RATs, namely RAT-1, RAT-2, and RAT-3) and the RAT list corresponding to the second connection (i.e., one or more RATs, namely RAT-a, RAT-b, RAT-c, and RAT-d).

[0240] RAT-1, RAT-2, and RAT-3 may not have priority, and RAT-a, RAT-b, RAT-c, and RAT-d may not have priority.

[0241] Alternatively, RAT-1, RAT-2, and RAT-3 can have priorities. In this example, the priorities of RAT-1, RAT-2, and RAT-3 can be implicitly indicated by decreasing priorities from left to right, that is, RAT-1 has the highest priority, RAT-2 has a lower priority than RAT-1, and RAT-3 has the lowest priority. RAT-a, RAT-b, RAT-c, and RAT-d may have priorities, and their related descriptions are similar to those of the aforementioned method-1, so they will not be repeated here.

[0242] In one scenario, the RAT list corresponding to the first connection contains or has priority, and the RAT list corresponding to the second connection also contains or has priority. The first network that can be accessed is determined sequentially according to the priority order of RAT-1, 2, 3. If one of these networks can be selected and registration completed, the first connection can be established. Then, the second network that can be accessed is determined sequentially according to the priority order of RAT-a, b, c, d.

[0243] Taking the first connection as an example, the mechanism of selecting the first network based on RAT can be combined with the existing PLMN selection mechanism. For instance, based on the PLMN selection mechanism in the relevant protocol, when considering or selecting the cell of the highest priority PLMN-3 (the first optional network), its RAT is RAT-2. This RAT-2 is not the highest priority RAT in Table 2. Therefore, based on the PLMN selection mechanism again, the second priority PLMN-4 (the reselected first optional network) is considered or selected. If the cell of PLMN-4 has a RAT-1 type, then PLMN-4 is selected as the first network. The registration process is initiated and completed in the cell under this first network, and the terminal establishes the first connection under this first network. Otherwise, based on the PLMN selection mechanism again, the RAT type of the cell of the next priority PLMN is considered, and so on. This will not be elaborated further.

[0244] After establishing the first connection on the first network, the terminal then selects and establishes a connection on the second network. The selection of the second network is the same as that of the first network and will not be described in detail.

[0245] In one scenario, the RAT list corresponding to the first connection does not contain or has no priority, and the RAT list corresponding to the second connection also does not contain or has no priority. Select one of RATs 1, 2, and 3 as the first network. If one can be selected and the first connection established, then select the second network from RATs a, b, c, and d to establish the second connection.

[0246] Taking the first connection as an example, the mechanism of selecting the first network based on RAT can be combined with the existing PLMN selection mechanism. For instance, when considering or selecting the cell of the highest priority PLMN-1 (the first optional network) based on the PLMN selection mechanism in the relevant protocol, its RAT is RAT-4, which is not in the RAT list corresponding to the first connection in Table 2. Then, based on the PLMN selection mechanism, considering or selecting the second priority PLMN-2 (the first optional network to be reselected), if the cell of PLMN-2 has a RAT-2 type (in the RAT list corresponding to the first connection), PLMN-2 is selected as the first network. The registration process is initiated and completed in the first network (the cell under the first network), and the terminal establishes the first connection under the first network. Otherwise, based on the PLMN selection mechanism in the relevant protocol, the RAT type of the cell of the next priority PLMN is considered, and so on.

[0247] After establishing the first connection in the first network, the second network is selected and a connection is established. The selection of the second network is the same as that of the first network and will not be elaborated further.

[0248] It should be noted that in actual processing, Method-2 can also be used without combining it with the existing PLMN selection mechanism. For example, a network corresponding to a certain RAT can be selected from the RAT list corresponding to the first connection as the first network. Then, the registration process can be initiated and completed on that RAT network, and the first connection can be established on that network. After selecting the first connection, the selection of the second network for the second connection is the same as that for the first connection, and will not be elaborated further.

[0249] It should also be noted that the above method-2 is only an illustrative example. In actual processing, the RAT lists corresponding to the first connection and the second connection included in the first information can also be replaced with one or more networks corresponding to the first connection and the second connection, or replaced with one or more combined information corresponding to the first connection and the second connection. Regarding the case where the first information includes one or more networks corresponding to the first connection and the second connection, or one or more combined information corresponding to the first connection and the second connection, the specific processing of selecting the first network based on the first information and selecting the second network based on the first information is the same as the aforementioned embodiment, and therefore will not be repeated.

[0250] Method 3: Select the first network based on the RAT corresponding to the first connection in the first information, and then establish the first connection; select the second network based on the first network and the first association relationship in the first information, and then establish the second connection.

[0251] The first information of Method-3 is illustrated in Table 3 as an example:

[0252] Table 3

[0253] The first information shown in Table 3 includes the RAT list (RAT-1, RAT-2, RAT-3) corresponding to the first connection and the RAT list (RAT-a, RAT-b, RAT-c, RAT-d) corresponding to the second connection. This first information also includes a first association relationship, meaning that RAT-1, RAT-2, and RAT-3 are associated with RAT-a, RAT-b, RAT-c, and RAT-d, respectively. Specifically, RAT-1 corresponding to the first connection is associated with RAT-a corresponding to the second connection, RAT-2 corresponding to the first connection is associated with RAT-b corresponding to the second connection, and RAT-3 corresponding to the first connection is associated with RAT-c and RAT-d corresponding to the second connection.

[0254] RAT-1, RAT-2, and RAT-3 may not have priority. Correspondingly, RAT-a, RAT-b, RAT-c, and RAT-d associated with RAT-1 to RAT-3 may not have priority.

[0255] Alternatively, RAT-1, RAT-2, and RAT-3 can have priorities. For example, in this example, the priorities of RAT-1, RAT-2, and RAT-3 can be implicitly indicated by decreasing priorities from top to bottom, meaning RAT-1 has the highest priority, RAT-2 has a lower priority than RAT-1, and RAT-3 has the lowest priority. Optionally, RAT-a associated with RAT-1 has the highest priority, RAT-b associated with RAT-2 has a medium priority, and RAT-c and RAT-d associated with RAT-3 have the lowest priority.

[0256] In Method-3, the terminal selects the first network based on the first information (including one or more RATs corresponding to the first connection), which is similar to the previous embodiments and therefore will not be described again.

[0257] In Method 3, the second network is selected based on the first association relationship in the first network and the first information (i.e., the association relationship between the first RAT corresponding to the first connection and the RAT corresponding to the second connection). That is, if the first network selects the network corresponding to RAT-1 with the highest priority and completes registration and establishes the first connection in the first network, then only the network corresponding to RAT-a can be selected as the second network; furthermore, if the registration in the second network is successful, then the second connection is established under the second network.

[0258] Additionally, if registration on the second network fails, the following two scenarios can be considered: 1) The first connection reselects the network corresponding to the next lower priority RAT (i.e., RAT-2), giving the terminal's second connection a chance to try selecting a network for another RAT (RAT-b); 2) The terminal cancels the DualSteer function and uses only the first connection. Optionally, the terminal can attempt to register on the second network again (or periodically) (and attempt to establish a second connection).

[0259] Method 4: Select a first network based on the network corresponding to the first connection in the first information, and then establish the first connection; select a second network based on the second association relationship between the first network and the first information, and then establish the second connection.

[0260] Referring to Table 4, taking PLMN as an example, the first information of Method-4 is illustrated as follows:

[0261] Table 4

[0262] The first information shown in Table 4 includes the PLMN list (PLMN-1 to PLMN-3) corresponding to the first connection and the PLMN list (PLMN-a to PLMN-d) corresponding to the second connection. This first information also includes a second association relationship, meaning that PLMN-1 to PLMN-3 are associated with PLMN-a to PLMN-d respectively; specifically, PLMN-1 corresponding to the first connection is associated with PLMN-a corresponding to the second connection, PLMN-2 corresponding to the first connection is associated with PLMN-b corresponding to the second connection, and PLMN-3 corresponding to the first connection is associated with PLMN-c and PLMN-d corresponding to the second connection.

[0263] PLMN-1 to PLMN-3 may not have priority, and correspondingly, PLMN-a to PLMN-d may not have priority.

[0264] Alternatively, PLMN-1 to PLMN-3 can have priorities. For example, in this example, the priorities of PLMN-1 to PLMN-3 can be implicitly indicated by decreasing the priority from top to bottom according to the arrangement order, that is, PLMN-1 has the highest priority, PLMN-2 has a lower priority than PLMN-1, and PLMN-3 has the lowest priority.

[0265] In Method-4, the process of the terminal selecting the first network based on the first information (including one or more PLMNs corresponding to the first connection) is similar to that in the previous embodiments, and therefore will not be described again.

[0266] In method-4, the second network is selected based on the second association relationship in the first network and the first information (i.e., the association relationship between the first PLMN corresponding to the first connection and the PLMN corresponding to the second connection). That is, if the first network selects PLMN-1 and completes registration and establishes the first connection in the first network, then only PLMN-a can be selected as the second network; furthermore, if the registration in the second network is successful, then the second connection is established under the second network.

[0267] Additionally, if registration on the second network fails (i.e., PLMN-a cannot be selected), the following two scenarios can be considered: 1) The first connection reselects a PLMN of the next lower priority (i.e., PLMN-2), giving the terminal's second connection a chance to try selecting another PLMN (PLMN-b); 2) The terminal cancels the DualSteer function and uses only the first connection. Optionally, the terminal can attempt to register on the second network again (or periodically) (and attempt to establish a second connection).

[0268] Method 5: Select a first network based on the combined information corresponding to the first connection in the first information, and then establish the first connection; select a second network based on the third association relationship between the first network and the first information, and then establish the second connection.

[0269] Referring to Table 5, taking a network type of PLMN as an example, the first information of Method-5 is explained exemplarily:

[0270] Table 5

[0271] The first information shown in Table 5 includes the combination information corresponding to the first connection and the combination information corresponding to the second connection. This first information also includes a third association relationship. Specifically, the combination information PLMN-1 / RAT-1 corresponding to the first connection is associated with the combination information PLMN-a / RAT-a corresponding to the second connection, PLMN-2 / RAT-2 corresponding to the first connection is associated with PLMN-b / RAT-b corresponding to the second connection, and PLMN-3 / RAT-3 corresponding to the first connection is associated with PLMN-c / RAT-c and PLMN-d / RAT-d corresponding to the second connection.

[0272] The combined information corresponding to the first connection may not have priority, and correspondingly, the combined information corresponding to the second connection may not have priority.

[0273] Alternatively, the combination information corresponding to the first connection can have a priority. For example, in this example, the priority of the combination information corresponding to the first connection can be implicitly indicated by decreasing the priority from top to bottom according to the arrangement order, that is, PLMN-1 / RAT-1 has the highest priority, PLMN-2 / RAT-2 has the next highest priority, and PLMN-3 / RAT-3 has the lowest priority.

[0274] In Method-5, the terminal selects the first network based on the first information (including one or more combined information corresponding to the first connection), which is similar to the previous embodiments and therefore will not be described again.

[0275] In Method 5, the second network is selected based on the third association relationship in the first network and the first information (i.e., the association relationship between the first combined information corresponding to the first connection and the combined information corresponding to the second connection). That is, if the first network selects PLMN-1 / RAT-1 and completes registration and establishes the first connection in the first network, then only PLMN-a / RAT-a can be selected as the second optional network; furthermore, if the registration in the second optional network is successful, then the second optional network becomes the second network, and the second connection is established under the second network.

[0276] Additionally, if registration on the second optional network fails (i.e., PLMN-a / RAT-a cannot be selected), the following two scenarios can be considered: 1) The first connection reselects the next lower priority combination information, i.e., PLMN-2 / RAT-2, giving the terminal's second connection a chance to try selecting other combinations (PLMN-b / RAT-b); 2) The terminal cancels the DualSteer function and uses only the first connection. However, additionally, the terminal can attempt to register on the second optional network again (or periodically) (and attempt to establish a second connection).

[0277] In this way, the terminal can select multiple networks by pre-configured or default first information, and when the terminal selects multiple networks based on the first information, the dependency between the selection of multiple networks is also considered, so that the terminal can more reasonably select multiple networks and establish multiple connections.

[0278] In some possible implementations, after the terminal establishes the second connection on the second network, it further includes one of the following: in the event that the first connection is lost, performing at least one of the following: the terminal maintains the second connection, the terminal releases the second connection, the terminal reselects the first network, and the terminal reselects the second network based on the first information; in the event that the second connection is lost, performing at least one of the following: the terminal maintains the first connection, the terminal releases the first connection, the terminal reselects the first network, and the terminal reselects the second network based on the first information.

[0279] In this embodiment, connection loss refers to the terminal's inability to maintain registration in the selected network or its inability to maintain a user plane connection. After successful network selection based on the first information, the following situations may occur: first connection loss and / or second connection loss.

[0280] In one embodiment, in the event of a first connection loss, processing may be performed in any of the following three modes:

[0281] Mode-a1: The terminal maintains the second connection. That is, the terminal uses the second connection normally.

[0282] In mode-b1, the terminal releasing the second connection includes: the terminal releasing the second connection when it is in an idle state. This release may include: the terminal registering with the current network (i.e., the second network), and / or the terminal releasing the user plane connection (i.e., the second connection) of the current network (i.e., the second network).

[0283] In other words, the terminal's second connection is released when it is in an idle state; for example, if the terminal is currently in a connected state, it will wait until it becomes idle before releasing the second connection; if the terminal is currently in an idle state, it can release the second connection directly.

[0284] In mode-c1, the terminal releasing the second connection includes: the terminal immediately releasing the second connection. That is, regardless of the terminal's current state, as soon as the first connection is lost, the second connection is immediately released.

[0285] Furthermore, in any of the above modes, the terminal can also perform the following processing: the terminal reselects the first network and / or the terminal reselects the second network based on the first information. Here, the terminal reselecting the first network can mean that the terminal can reselect the first network based on the PLMN selection mechanism; or, the terminal can reselect the first network based on the first information. The processing of the terminal reselecting the first network will not be repeated here. The processing of the terminal reselecting the second network based on the first information is the same as in the aforementioned embodiments and will not be described in detail.

[0286] Optionally, in mode-a1 where the first connection is lost, the terminal maintains the second connection while reselecting the first network.

[0287] Optionally, in mode-a1 where the first connection is lost, the terminal maintains the second connection while reselecting the first network; after the terminal establishes the first connection under the reselected first network, the second connection is released, and then the terminal reselects the second network based on the first information.

[0288] Optionally, in mode-b1 where the first connection is lost, the terminal releases the second connection when it is in an idle state, and the terminal reselects the first network; after the terminal establishes the first connection under the reselected first network, the terminal reselects the second network based on the first information.

[0289] Optionally, in mode-c1 where the first connection is lost, the terminal immediately releases the second connection and reselects the first network; after the terminal establishes the first connection in the reselected first network, the terminal reselects the second network based on the first information.

[0290] It should be noted that, in the event of the first connection loss, the processing mode to be executed among the three modes—mode-a1, mode-b1, and mode-c1—can be determined by the terminal's default setting, the protocol's specification, or a pre-configured setting.

[0291] If, in the event of a first connection loss, the terminal is pre-configured to execute processing in any of the three modes—Mode-a1, Mode-b1, and Mode-c1—then it may receive a pre-configured mode configuration message. This mode configuration message may be configured to the terminal by any core network device or core network control plane element in the first or second network (e.g., a second core network device in the second network or a first core network device in the first network). This mode configuration message may be carried via a fourth NAS message; the type of core network control plane element configuring this mode configuration message is not limited here.

[0292] The mode configuration related message may include indication information for any one of the three modes mentioned above. For example, the mode configuration related message may directly include operation instructions for any one of the three modes (such as releasing the second connection in idle state). Or, the mode configuration related message may include identification information for any one of the three modes (such as indicating mode-a1, mode-b1, or mode-c1). Or, the mode configuration related message may include policy information on which mode the terminal specifically adopts for processing, so that the terminal can determine which of the three modes to use for processing based on the relevant policy information.

[0293] In some possible examples, if the first connection is the primary connection, then mode -c may be preferred. This is merely illustrative and is not intended to limit the choice of which of the three modes to use in actual processing.

[0294] In one embodiment, in the event of a second connection loss, processing may be performed in any of the following three modes:

[0295] Mode-a2: The terminal maintains the first connection. That is, the terminal uses the first connection normally.

[0296] In mode-b2, the terminal releasing the first connection includes: the terminal releasing the first connection when it is in an idle state. This release may include: the terminal registering with the current network (i.e., the first network), and / or the terminal releasing the user plane connection (i.e., the first connection) of the current network (i.e., the first network).

[0297] In other words, the terminal's first connection is released when it is in an idle state; for example, if the terminal is currently in a connected state, it will wait until it becomes idle before releasing the first connection; if the terminal is currently in an idle state, it can release the first connection directly.

[0298] In mode-c2, the terminal releasing the first connection includes: the terminal immediately releasing the first connection. That is, regardless of the terminal's current state, as soon as the second connection is lost, the first connection is immediately released.

[0299] Furthermore, in any of the above modes, the terminal may also perform the following processing: the terminal reselects the first network and / or the terminal reselects the second network based on the first information. The processing related to the terminal reselecting the first network and the terminal reselecting the second network based on the first information is the same as in the aforementioned embodiments and will not be described again.

[0300] Optionally, in mode-a2 where the second connection is lost, the terminal maintains the first connection while reselecting the second network based on the first information.

[0301] Optionally, in mode-a2 where the second connection is lost, while the terminal maintains the first connection, the terminal reselects the second network based on the first information; then the first connection can be released, the first network can be reselected, and the first connection can be re-established on the first network.

[0302] Optionally, in mode-b2 where the second connection is lost, the terminal releases the first connection when it is in an idle state, and the terminal reselects the first network; after the terminal establishes the first connection under the reselected first network, the terminal reselects the second network based on the first information.

[0303] Optionally, in mode-c2 where the second connection is lost, the terminal immediately releases the first connection and reselects the first network; after the terminal establishes the first connection in the reselected first network, the terminal reselects the second network based on the first information.

[0304] It should be noted that, in the event of a second connection loss, the processing method chosen from among mode-a2, mode-b2, and mode-c2 can be the terminal's default setting, a protocol-defined setting, or a pre-configured setting. If the processing method chosen from among mode-a2, mode-b2, and mode-c2 is pre-configured in the event of a second connection loss, the terminal may have pre-received mode configuration-related messages. The mode configuration-related messages and their descriptions are similar to those in the aforementioned embodiments and will not be repeated here.

[0305] In some possible examples, if the first connection is the primary connection and the second connection is lost, then mode-a2 or mode-b2 may be preferred. This is merely an illustrative example and is not intended to limit the choice of which of the three modes to use in actual processing.

[0306] This allows for consideration of how to handle connection issues that arise when a terminal selects multiple networks, thus ensuring connection stability.

[0307] Finally, it should be noted that the above descriptions mainly focus on various embodiments based on the first and second connections. In actual processing, the solutions provided in this embodiment can be applied to situations with more connections.

[0308] For example, if the first connection is the first connection established and the second connection is the second connection established, after the second connection is established, a third network can be selected and a third connection can be established on the third network, and so on. The terminal can establish more connections on more networks.

[0309] In this case, the first information may include not only the RAT, network, or combination information corresponding to the first connection and the RAT, network, or combination information corresponding to the second connection in the above embodiments, but may also include the RAT, network, or combination information corresponding to the third connection and other more connections, which will not be elaborated here.

[0310] Optionally, the first association relationship in the first information may include not only the association relationship between the RAT corresponding to the first connection and the RAT corresponding to the second connection, but also the association relationships between RATs corresponding to other connections. For example, RATs corresponding to other connections may also have an association relationship with the RAT corresponding to the first connection; or, for example, RATs corresponding to other connections may have an association relationship with each other, etc., without limitation or exhaustive list.

[0311] Optionally, the second association in the first information may include not only the association between the network corresponding to the first connection and the network corresponding to the second connection, but also the association between networks corresponding to other connections. For example, networks corresponding to other connections may also have associations with the network corresponding to the first connection, etc., without limitation or exhaustive listing.

[0312] Optionally, the third association in the first information may include not only the association between the combined information corresponding to the first connection and the combined information corresponding to the second connection, but also the association between the combined information corresponding to other connections. For example, the combined information corresponding to other connections may also have an association with the combined information corresponding to the first connection, etc., without limitation or exhaustive list.

[0313] The process of the terminal selecting more other networks based on the first information is similar to the process of the terminal selecting the first network or the second network based on the first information, so it will not be described in detail.

[0314] By adopting the above scheme, the terminal can, based on the first connection established on the first network, further select a second network according to the first information. This second network can then be used by the terminal to establish a second connection. In this way, the terminal can combine the first information to select more networks, thereby enabling the terminal to establish multiple connections across multiple networks and ultimately achieve data transmission through multiple connections.

[0315] Figure 5 is a schematic diagram of the composition structure of a terminal according to an embodiment of this application, including:

[0316] The first processing unit 501 is used to select a second network based on first information when a first connection is established under the first network.

[0317] The first information includes at least one of the following: one or more Radio Access Technologies (RATs) corresponding to the second connection, the priority of one or more RATs corresponding to the second connection, one or more networks corresponding to the second connection, the priority of one or more networks corresponding to the second connection, one or more combination information corresponding to the second connection, and the priority of one or more combination information corresponding to the second connection, wherein the combination information includes the network and the RAT, and the second connection is established by the terminal under the second network.

[0318] The first processing unit is configured to select a second optional network based on a network selection mechanism; if the second optional network matches the first information, the second optional network is selected as the second network.

[0319] The matching of the second optional network with the first information includes one of the following: the RAT corresponding to the second optional network matches one of the one or more RATs corresponding to the second connection included in the first information; the RAT corresponding to the second optional network matches the highest priority RAT among the one or more RATs corresponding to the second connection included in the first information; the second optional network matches one of the one or more networks corresponding to the second connection included in the first information; the second optional network matches the highest priority network among the one or more networks corresponding to the second connection included in the first information; the second optional network and the RAT corresponding to the second optional network match one of the one or more combined information corresponding to the second connection included in the first information; the second optional network and the RAT corresponding to the second optional network match the highest priority combined information among the one or more combined information corresponding to the second connection included in the first information.

[0320] The first processing unit is configured to reselect the second optional network based on the network selection mechanism if the second optional network does not match the first information and / or if registration with the second network fails.

[0321] The first processing unit is configured to perform one of the following: selecting a second RAT from one or more RATs corresponding to the second connection included in the first information, and designating the network corresponding to the second RAT as the second network; selecting the highest priority RAT from one or more RATs corresponding to the second connection included in the first information, and designating the network corresponding to the highest priority RAT as the second network; selecting the second network from one or more networks corresponding to the second connection included in the first information; selecting the highest priority network from one or more networks corresponding to the second connection included in the first information as the second network; selecting second combination information from one or more combination information corresponding to the second connection included in the first information, and designating the network contained in the second combination information as the second network; selecting the highest priority combination information from one or more combination information corresponding to the second connection included in the first information, and designating the network contained in the highest priority combination information as the second network.

[0322] The first processing unit is configured to reselect the second network based on the first information if the registration with the second network fails.

[0323] The first information includes one of the following: a first association relationship between one or more RATs corresponding to the first connection and one or more RATs corresponding to the second connection; a second association relationship between one or more networks corresponding to the first connection and one or more networks corresponding to the second connection; and a third association relationship between one or more combined information corresponding to the first connection and one or more combined information corresponding to the second connection.

[0324] The first processing unit is configured to select the second network based on the first network and the first information.

[0325] The first processing unit is configured to perform one of the following: determining a second RAT corresponding to the second connection based on the RAT corresponding to the first network and a first association relationship contained in the first information, and using the network corresponding to the second RAT as the second network, wherein the RAT corresponding to the first network is one of one or more RATs corresponding to the first connection; determining the second network based on the first network and a second association relationship contained in the first information, wherein the first network is one of one or more networks corresponding to the first connection; determining a second combination information corresponding to the second connection associated with the first network and its corresponding RAT based on the first network and its corresponding RAT and a third association relationship contained in the first information, and using the network contained in the second combination information as the second network, wherein the first network and its corresponding RAT are one of one or more combination information corresponding to the first connection.

[0326] The first processing unit is configured to perform one of the following: if the terminal fails to register with the second network, reselect the first network; or if the terminal fails to register with the second network, cancel the multi-connection function.

[0327] As shown in Figure 5, the terminal also includes:

[0328] The first communication unit 502 is configured to send a multi-connection disable instruction when the multi-connection function is cancelled, wherein the multi-connection disable instruction is used to instruct the terminal to disable the multi-connection function.

[0329] The first processing unit is configured to establish the second connection on the second network if the registration on the second network is successful.

[0330] The first communication unit is configured to receive a multi-connection enable indication, wherein the multi-connection enable indication is used for the terminal to enable the multi-connection function.

[0331] The first information includes at least one of the following: one or more RATs corresponding to the first connection, the priority of one or more RATs corresponding to the first connection, one or more networks corresponding to the first connection, the priority of one or more networks corresponding to the first connection, one or more combination information corresponding to the first connection, and the priority of one or more combination information corresponding to the first connection, wherein the combination information includes networks and RATs.

[0332] The first processing unit is configured to select a first network based on the first information.

[0333] The first processing unit is configured to select a first optional network based on a network selection mechanism; and if the first optional network matches the first information, the first optional network is selected as the first network.

[0334] The matching of the first optional network with the first information includes one of the following: the RAT corresponding to the first optional network matches one of the one or more RATs corresponding to the first connection included in the first information; the RAT corresponding to the first optional network matches the highest priority RAT among the one or more RATs corresponding to the first connection included in the first information; the first optional network matches one of the one or more networks corresponding to the first connection included in the first information; the first optional network matches the highest priority network among the one or more networks corresponding to the first connection included in the first information; the first optional network and the RAT corresponding to the first optional network match one of the one or more combined information corresponding to the first connection included in the first information; the first optional network and the RAT corresponding to the first optional network match the highest priority combined information among the one or more combined information corresponding to the first connection included in the first information.

[0335] The first processing unit is configured to reselect the first optional network based on the network selection mechanism if the first optional network does not match the first information and / or if registration on the first network fails.

[0336] The first processing unit is configured to perform one of the following: selecting a first RAT from one or more RATs corresponding to the first connection included in the first information, and designating the network corresponding to the first RAT as the first network; selecting the highest priority RAT from one or more RATs corresponding to the first connection included in the first information, and designating the network corresponding to the highest priority RAT as the first network; selecting the first network from one or more networks corresponding to the first connection included in the first information; selecting the highest priority network from one or more networks corresponding to the first connection included in the first information, and designating the network contained in the first combination information as the first network; selecting the highest priority combination information from one or more combination information corresponding to the first connection included in the first information, and designating the network contained in the highest priority combination information as the first network.

[0337] The first processing unit is configured to reselect the first network based on the first information if the first network registration fails.

[0338] The first processing unit is configured to establish the first connection on the first network if the registration on the first network is successful.

[0339] The first processing unit is configured to perform one of the following: in the event that the first connection is lost, perform at least one of the following: maintain the second connection, release the second connection, reselect the first network, and reselect the second network based on the first information; in the event that the second connection is lost, perform at least one of the following: maintain the first connection, release the first connection, reselect the first network, and reselect the second network based on the first information.

[0340] The first processing unit is used to release the second connection when the terminal is in an idle state.

[0341] The first processing unit is used to release the first connection when the terminal is in an idle state.

[0342] The first piece of information is either default or specified by the protocol.

[0343] The first communication unit is used to receive the first information.

[0344] Figure 6 is a schematic diagram of the composition structure of a first core network device according to an embodiment of this application, including:

[0345] The second communication unit 601 is used to send first information to the terminal, wherein the first information is used by the terminal to select a second network.

[0346] The first information includes at least one of the following: one or more RATs corresponding to the second connection, the priority of one or more RATs corresponding to the second connection, one or more networks corresponding to the second connection, the priority of one or more networks corresponding to the second connection, one or more combination information corresponding to the second connection, and the priority of one or more combination information corresponding to the second connection, wherein the combination information includes networks and RATs, and the second connection is established by the terminal under the second network.

[0347] The first information includes one of the following: a first association relationship between one or more RATs corresponding to the first connection and one or more RATs corresponding to the second connection; a second association relationship between one or more networks corresponding to the first connection and one or more networks corresponding to the second connection; and a third association relationship between one or more combined information corresponding to the first connection and one or more combined information corresponding to the second connection, wherein the first connection is established by the terminal under the first network.

[0348] The first information includes at least one of the following: one or more RATs corresponding to the first connection, the priority of one or more RATs corresponding to the first connection, one or more networks corresponding to the first connection, the priority of one or more networks corresponding to the first connection, one or more combination information corresponding to the first connection, and the priority of one or more combination information corresponding to the first connection, wherein the combination information includes networks and RATs, and the first connection is established by the terminal under the first network.

[0349] The first information is also used by the terminal to select the first network.

[0350] The second communication unit is used to send a multi-connection enable indication to the terminal, wherein the multi-connection enable indication is used for the terminal to enable the multi-connection function.

[0351] The second communication unit is configured to receive a multi-connection disable indication from the terminal, wherein the multi-connection disable indication is configured to instruct the terminal to disable the multi-connection function.

[0352] The device in this application embodiment can realize the corresponding functions of the devices in the foregoing configuration method embodiments. The processes, functions, implementation methods, and beneficial effects of each module (sub-module, unit, or component, etc.) in this device can be found in the corresponding descriptions in the above method embodiments, and will not be repeated here. It should be noted that the functions described for each module (sub-module, unit, or component, etc.) in the device of this application embodiment can be implemented by different modules (sub-modules, units, or components, etc.) or by the same module (sub-module, unit, or component, etc.).

[0353] Figure 7 is a schematic structural diagram of a communication device 700 according to an embodiment of this application. The communication device 700 includes a processor 710, which can call and run computer programs from a memory to enable the communication device 700 to implement the methods in the embodiments of this application. In one possible implementation, the communication device 700 may further include a memory 720. The processor 710 can call and run computer programs from the memory 720 to enable the communication device 700 to implement the methods in the embodiments of this application. The memory 720 may be a separate device independent of the processor 710, or it may be integrated into the processor 710. In one possible implementation, the communication device 700 may further include a transceiver 730, which the processor 710 can control to communicate with other devices. Specifically, it can send information or data to other devices, or receive information or data sent by other devices. The transceiver 730 may include a transmitter and a receiver. The transceiver 730 may further include antennas, and the number of antennas may be one or more.

[0354] In one possible implementation, the communication device 700 may be a terminal or a first core network device in the embodiments of this application, and the communication device 700 may implement the corresponding processes implemented by the terminal or the first core network device in the various methods of the embodiments of this application. For the sake of brevity, it will not be described in detail here.

[0355] Figure 8 is a schematic structural diagram of a chip 800 according to an embodiment of this application. The chip 800 includes a processor 810, which can call and run computer programs from memory to implement the methods in the embodiments of this application. In one possible implementation, the chip 800 may further include a memory 820. The processor 810 can call and run computer programs from the memory 820 to implement the methods executed by the terminal in the embodiments of this application. The memory 820 may be a separate device independent of the processor 810, or it may be integrated into the processor 810. In one possible implementation, the chip 800 may further include an input interface 830. The processor 810 can control the input interface 830 to communicate with other devices or chips, specifically, to acquire information or data sent by other devices or chips. In one possible implementation, the chip 800 may further include an output interface 840. The processor 810 can control the output interface 840 to communicate with other devices or chips, specifically, to output information or data to other devices or chips.

[0356] In one possible implementation, the chip can be applied to the terminal or the first core network device in the embodiments of this application, and the chip can implement the corresponding processes implemented by the terminal or the first core network device in the various methods of the embodiments of this application. For simplicity, these will not be elaborated further here. It should be understood that the chip mentioned in the embodiments of this application can also be called a system-on-a-chip, system chip, chip system, or system-on-a-chip, etc. The processor mentioned above can be a general-purpose processor, a digital signal processor (DSP), a field-programmable gate array (FPGA), an application-specific integrated circuit (ASIC), or other programmable logic devices, transistor logic devices, discrete hardware components, etc. Among them, the general-purpose processor mentioned above can be a microprocessor or any conventional processor, etc. The memory mentioned above can be volatile memory or non-volatile memory, or can include both volatile and non-volatile memory. The non-volatile memory can be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. The volatile memory can be random access memory (RAM). It should be understood that the above-described memory is exemplary but not limiting. For example, the memory in the embodiments of this application can also be static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM), and direct memory bus RAM (DR RAM), etc. In other words, the memory in the embodiments of this application is intended to include, but is not limited to, these and any other suitable types of memory.

[0357] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, as a computer program product. This computer program product includes one or more computer instructions. When these computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another via wired (e.g., coaxial cable, fiber optic, Digital Subscriber Line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium accessible to a computer or a data storage device such as a server or data center that integrates one or more available media. The available media can be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., DVDs), or semiconductor media (e.g., solid-state drives (SSDs)).

[0358] Figure 9 is a schematic block diagram of a communication system 900 according to an embodiment of this application. The communication system 900 includes a terminal 910 and a first core network device 920. The terminal 910 can be used to implement the corresponding functions implemented by the terminal in the above-described method. The first core network device 920 can be used to implement the corresponding functions implemented by the first core network device in the above-described method. For simplicity, further details are omitted here.

[0359] It should be understood that in the various embodiments of this application, the sequence number of each process does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here. The above descriptions are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A network selection method, comprising: When a terminal establishes a first connection under a first network, the terminal selects a second network based on first information.

2. The method according to claim 1, wherein, The first information includes at least one of the following: one or more Radio Access Technologies (RATs) corresponding to the second connection, the priority of one or more RATs corresponding to the second connection, one or more networks corresponding to the second connection, the priority of one or more networks corresponding to the second connection, one or more combination information corresponding to the second connection, and the priority of one or more combination information corresponding to the second connection, wherein the combination information includes the network and the RAT, and the second connection is established by the terminal under the second network.

3. The method according to claim 2, wherein, The terminal selects the second network based on the first information, including: The terminal selects a second optional network based on a network selection mechanism; If the terminal matches the first information with the second optional network, it will use the second optional network as the second network.

4. The method according to claim 3, wherein, The second optional network that matches the first information includes one of the following: The RAT corresponding to the second optional network matches one or more RATs corresponding to the second connection contained in the first information; The RAT corresponding to the second optional network is matched with the highest priority RAT among one or more RATs corresponding to the second connection contained in the first information; The second optional network matches one or more networks corresponding to the second connection contained in the first information; The second optional network is matched with the highest priority network among one or more networks corresponding to the second connection contained in the first information; The second optional network and the RAT corresponding to the second optional network match one of one or more combinations of information corresponding to the second connection contained in the first information; The second optional network and the RAT corresponding to the second optional network are matched with the highest priority combination information among one or more combination information corresponding to the second connection contained in the first information.

5. The method according to claim 3 or 4, further comprising: If the second optional network does not match the first information, and / or if registration fails on the second network, the terminal reselects the second optional network based on the network selection mechanism.

6. The method according to claim 2, wherein, The terminal selects a second network based on the first information, including one of the following: The terminal selects a second RAT from one or more RATs corresponding to the second connection contained in the first information, and uses the network corresponding to the second RAT as the second network. The terminal selects the highest priority RAT from one or more RATs corresponding to the second connection contained in the first information, and uses the network corresponding to the highest priority RAT as the second network. The terminal selects the second network from one or more networks corresponding to the second connection included in the first information; The terminal selects the network with the highest priority from one or more networks corresponding to the second connection contained in the first information as the second network; The terminal selects a second combination of information from one or more combinations of information corresponding to the second connection contained in the first information, and uses the network contained in the second combination of information as the second network. The terminal selects the highest priority combination information from one or more combination information corresponding to the second connection contained in the first information, and uses the network contained in the highest priority combination information as the second network.

7. The method according to claim 6, further comprising: If the terminal fails to register on the second network, the terminal will reselect the second network based on the first information.

8. The method according to claim 2, wherein, The first information includes one of the following: a first association relationship between one or more RATs corresponding to the first connection and one or more RATs corresponding to the second connection; a second association relationship between one or more networks corresponding to the first connection and one or more networks corresponding to the second connection; and a third association relationship between one or more combined information corresponding to the first connection and one or more combined information corresponding to the second connection.

9. The method according to claim 8, wherein, The terminal selects a second network based on the first information, including: The terminal selects the second network based on the first network and the first information.

10. The method according to claim 9, wherein, The terminal selects the second network based on the first network and the first information, including one of the following: The terminal determines the second RAT corresponding to the second connection based on the RAT corresponding to the first network and the first association relationship contained in the first information, and takes the network corresponding to the second RAT as the second network, wherein the RAT corresponding to the first network is one of one or more RATs corresponding to the first connection; The terminal determines the second network based on the first network and the second association relationship contained in the first information, wherein the first network is one of one or more networks corresponding to the first connection; The terminal determines the second combination information corresponding to the second connection associated with the first network and its corresponding RAT based on the first network and the third association relationship contained in the first information, and takes the network contained in the second combination information as the second network, wherein the first network and its corresponding RAT are one of one or more combination information corresponding to the first connection.

11. The method according to claim 9 or 10, further comprising one of the following: If the terminal fails to register on the second network, the terminal will reselect the first network. If the terminal fails to register with the second network, the multi-connection function is cancelled.

12. The method of claim 11, further comprising: When the terminal cancels the multi-connection function, it sends a multi-connection disable instruction, wherein the multi-connection disable instruction is used to instruct the terminal to disable the multi-connection function.

13. The method according to any one of claims 3, 4, 6, 9, and 10, further comprising: If the terminal successfully registers on the second network, the terminal establishes the second connection on the second network.

14. The method according to any one of claims 1-13, further comprising: The terminal receives a multi-connection enable instruction, wherein the multi-connection enable instruction is used by the terminal to enable the multi-connection function.

15. The method according to any one of claims 1-14, wherein, The first information includes at least one of the following: one or more RATs corresponding to the first connection, the priority of one or more RATs corresponding to the first connection, one or more networks corresponding to the first connection, the priority of one or more networks corresponding to the first connection, one or more combination information corresponding to the first connection, and the priority of one or more combination information corresponding to the first connection, wherein the combination information includes networks and RATs.

16. The method according to claim 15, wherein, Before the terminal establishes the first connection under the first network, it also includes: The terminal selects the first network based on the first information.

17. The method according to claim 16, wherein, The terminal selects the first network based on the first information, including: The terminal selects a first available network based on a network selection mechanism; If the terminal matches the first optional network with the first information, it will use the first optional network as the first network.

18. The method according to claim 17, wherein, The first optional network matching the first information includes one of the following: The RAT corresponding to the first optional network matches one or more of the RATs corresponding to the first connection contained in the first information; The RAT corresponding to the first optional network is matched with the highest priority RAT among one or more RATs corresponding to the first connection contained in the first information; The first optional network matches one or more networks corresponding to the first connection contained in the first information; The first optional network is matched with the highest priority network among one or more networks corresponding to the first connection contained in the first information; The first optional network and the RAT corresponding to the first optional network are matched with one of one or more combined information corresponding to the first connection contained in the first information; The first optional network and the RAT corresponding to the first optional network are matched with the highest priority combination information among one or more combination information corresponding to the first connection contained in the first information.

19. The method according to claim 17 or 18, further comprising: If the terminal does not match the first optional network with the first information, and / or fails to register on the first network, the terminal reselects the first optional network based on the network selection mechanism.

20. The method of claim 16, wherein, The terminal selects the first network based on the first information, including one of the following: The terminal selects a first RAT from one or more RATs corresponding to the first connection contained in the first information, and uses the network corresponding to the first RAT as the first network. The terminal selects the highest priority RAT from one or more RATs corresponding to the first connection contained in the first information, and uses the network corresponding to the highest priority RAT as the first network. The terminal selects the first network from one or more networks corresponding to the first connection contained in the first information; The terminal selects the network with the highest priority from one or more networks corresponding to the first connection contained in the first information as the first network; The terminal selects a first combination of information from one or more combinations of information corresponding to the first connection contained in the first information, and uses the network contained in the first combination of information as the first network. The terminal selects the highest priority option from one or more combinations of information corresponding to the first connection included in the first information. The network containing the highest priority combination information is selected as the first network.

21. The method of claim 20, further comprising: If the terminal fails to register on the first network, it can reselect the first network based on the first information.

22. The method according to any one of claims 16-18, 20, further comprising: If the terminal successfully registers on the first network, the terminal establishes the first connection on the first network.

23. The method according to claim 13, wherein, After the terminal establishes the second connection on the second network, it also includes one of the following: In the event that the first connection is lost, at least one of the following is performed: the terminal maintains the second connection, the terminal releases the second connection, the terminal reselects the first network, or the terminal reselects the second network based on the first information; In the event that the second connection is lost, at least one of the following actions shall be performed: the terminal maintains the first connection, the terminal releases the first connection, the terminal reselects the first network, or the terminal reselects the second network based on the first information.

24. The method according to claim 23, wherein, The terminal releasing the second connection includes: The terminal releases the second connection when it is in an idle state.

25. The method according to claim 23, wherein, The terminal releasing the first connection includes: The terminal releases the first connection when it is in an idle state.

26. The method according to any one of claims 1-25, wherein, The first piece of information is either default or specified by the protocol.

27. The method according to any one of claims 1-25, further comprising: The terminal receives the first information.

28. A network selection method, comprising: The first core network device sends first information to the terminal, wherein the first information is used by the terminal to select a second network.

29. The method according to claim 28, wherein, The first information includes at least one of the following: one or more Radio Access Technologies (RATs) corresponding to the second connection, the priority of one or more RATs corresponding to the second connection, one or more networks corresponding to the second connection, the priority of one or more networks corresponding to the second connection, one or more combination information corresponding to the second connection, and the priority of one or more combination information corresponding to the second connection, wherein the combination information includes the network and the RAT, and the second connection is established by the terminal under the second network.

30. The method according to claim 29, wherein, The first information includes one of the following: a first association relationship between one or more RATs corresponding to the first connection and one or more RATs corresponding to the second connection; a second association relationship between one or more networks corresponding to the first connection and one or more networks corresponding to the second connection; and a third association relationship between one or more combined information corresponding to the first connection and one or more combined information corresponding to the second connection, wherein the first connection is established by the terminal under the first network.

31. The method according to claim 29 or 30, wherein, The first information includes at least one of the following: one or more RATs corresponding to the first connection, the priority of one or more RATs corresponding to the first connection, one or more networks corresponding to the first connection, the priority of one or more networks corresponding to the first connection, one or more combination information corresponding to the first connection, and the priority of one or more combination information corresponding to the first connection, wherein the combination information includes networks and RATs, and the first connection is established by the terminal under the first network.

32. The method according to claim 31, wherein, The first information is also used by the terminal to select the first network.

33. The method according to any one of claims 28-32, further comprising: The first core network device sends a multi-connection enable instruction to the terminal, wherein the multi-connection enable instruction is used for the terminal to enable the multi-connection function.

34. The method according to claim 33, wherein, After the first core network device sends a multi-connection enable instruction to the terminal, the method further includes: The first core network device receives a multi-connection disable instruction from the terminal, wherein the multi-connection disable instruction is used to instruct the terminal to disable the multi-connection function.

35. A terminal, comprising: The first processing unit is used to select a second network based on first information when a first connection is established under the first network.

36. The terminal according to claim 35, wherein, The first information includes at least one of the following: one or more Radio Access Technologies (RATs) corresponding to the second connection, the priority of one or more RATs corresponding to the second connection, one or more networks corresponding to the second connection, the priority of one or more networks corresponding to the second connection, one or more combination information corresponding to the second connection, and the priority of one or more combination information corresponding to the second connection, wherein the combination information includes the network and the RAT, and the second connection is established by the terminal under the second network.

37. The terminal according to claim 36, wherein, The first processing unit is configured to select a second optional network based on a network selection mechanism; if the second optional network matches the first information, the second optional network is selected as the second network.

38. The terminal according to claim 37, wherein, The matching of the second optional network with the first information includes one of the following: the RAT corresponding to the second optional network matches one of the one or more RATs corresponding to the second connection included in the first information; the RAT corresponding to the second optional network matches the highest priority RAT among the one or more RATs corresponding to the second connection included in the first information; the second optional network matches one of the one or more networks corresponding to the second connection included in the first information; the second optional network matches the highest priority network among the one or more networks corresponding to the second connection included in the first information; the second optional network and the RAT corresponding to the second optional network match one of the one or more combined information corresponding to the second connection included in the first information; the second optional network and the RAT corresponding to the second optional network match the highest priority combined information among the one or more combined information corresponding to the second connection included in the first information.

39. The terminal according to claim 37 or 38, wherein the first processing unit is configured to reselect the second optional network based on the network selection mechanism if the second optional network does not match the first information and / or if registration with the second network fails.

40. The terminal according to claim 36, wherein, The first processing unit is configured to perform one of the following: selecting a second RAT from one or more RATs corresponding to the second connection included in the first information, and designating the network corresponding to the second RAT as the second network; selecting the highest priority RAT from one or more RATs corresponding to the second connection included in the first information, and designating the network corresponding to the highest priority RAT as the second network; selecting the second network from one or more networks corresponding to the second connection included in the first information; selecting the highest priority network from one or more networks corresponding to the second connection included in the first information as the second network; selecting second combination information from one or more combination information corresponding to the second connection included in the first information, and designating the network contained in the second combination information as the second network; selecting the highest priority combination information from one or more combination information corresponding to the second connection included in the first information, and designating the network contained in the highest priority combination information as the second network.

41. The terminal according to claim 40, wherein the first processing unit is configured to reselect the second network based on the first information if the registration of the second network fails.

42. The terminal according to claim 36, wherein, The first information includes one of the following: a first association relationship between one or more RATs corresponding to the first connection and one or more RATs corresponding to the second connection; a second association relationship between one or more networks corresponding to the first connection and one or more networks corresponding to the second connection; and a third association relationship between one or more combined information corresponding to the first connection and one or more combined information corresponding to the second connection.

43. The terminal according to claim 42, wherein, The first processing unit is configured to select the second network based on the first network and the first information.

44. The terminal according to claim 43, wherein, The first processing unit is configured to perform one of the following: determining a second RAT corresponding to the second connection based on the RAT corresponding to the first network and a first association relationship contained in the first information, and using the network corresponding to the second RAT as the second network, wherein the RAT corresponding to the first network is one of one or more RATs corresponding to the first connection; determining the second network based on the first network and a second association relationship contained in the first information, wherein the first network is one of one or more networks corresponding to the first connection; determining a second combination information corresponding to the second connection associated with the first network and its corresponding RAT based on the first network and its corresponding RAT and a third association relationship contained in the first information, and using the network contained in the second combination information as the second network, wherein the first network and its corresponding RAT are one of one or more combination information corresponding to the first connection.

45. The terminal according to claim 43 or 44, wherein the first processing unit is configured to perform one of the following: if the terminal fails to register with the second network, reselect the first network; or if the terminal fails to register with the second network, cancel the multi-connection function.

46. ​​The terminal according to claim 45, further comprising: A first communication unit is configured to send a multi-connection disable instruction when the multi-connection function is cancelled, wherein the multi-connection disable instruction is used to instruct the terminal to disable the multi-connection function.

47. The terminal according to any one of claims 37, 38, 40, 43, and 44, wherein the first processing unit is configured to establish the second connection on the second network if the second network registration is successful.

48. The terminal according to any one of claims 35-47, further comprising: The first communication unit is used to receive a multi-connection enable indication, wherein the multi-connection enable indication is used for the terminal to enable the multi-connection function.

49. The terminal according to any one of claims 35-48, wherein, The first information includes at least one of the following: one or more RATs corresponding to the first connection, the priority of one or more RATs corresponding to the first connection, one or more networks corresponding to the first connection, the priority of one or more networks corresponding to the first connection, one or more combination information corresponding to the first connection, and the priority of one or more combination information corresponding to the first connection, wherein the combination information includes networks and RATs.

50. The terminal according to claim 49, wherein the first processing unit is configured to select the first network based on the first information.

51. The terminal according to claim 50, wherein, The first processing unit is configured to select a first optional network based on a network selection mechanism; and if the first optional network matches the first information, the first optional network is selected as the first network.

52. The terminal according to claim 51, wherein, The matching of the first optional network with the first information includes one of the following: the RAT corresponding to the first optional network matches one of the one or more RATs corresponding to the first connection included in the first information; the RAT corresponding to the first optional network matches the highest priority RAT among the one or more RATs corresponding to the first connection included in the first information; the first optional network matches one of the one or more networks corresponding to the first connection included in the first information; the first optional network matches the highest priority network among the one or more networks corresponding to the first connection included in the first information; the first optional network and the RAT corresponding to the first optional network match one of the one or more combined information corresponding to the first connection included in the first information; the first optional network and the RAT corresponding to the first optional network match the highest priority combined information among the one or more combined information corresponding to the first connection included in the first information.

53. The terminal according to claim 51 or 52, wherein the first processing unit is configured to reselect the first optional network based on the network selection mechanism if the first optional network does not match the first information and / or if registration on the first network fails.

54. The terminal according to claim 50, wherein, The first processing unit is configured to perform one of the following: selecting a first RAT from one or more RATs corresponding to the first connection included in the first information, and designating the network corresponding to the first RAT as the first network; selecting the highest priority RAT from one or more RATs corresponding to the first connection included in the first information, and designating the network corresponding to the highest priority RAT as the first network; selecting the first network from one or more networks corresponding to the first connection included in the first information; selecting the highest priority network from one or more networks corresponding to the first connection included in the first information, and designating the network contained in the first combination information as the first network; selecting the highest priority combination information from one or more combination information corresponding to the first connection included in the first information, and designating the network contained in the highest priority combination information as the first network.

55. The terminal according to claim 54, wherein the first processing unit is configured to reselect the first network based on the first information if the first network registration fails.

56. The terminal according to any one of claims 50-52, 54, wherein the first processing unit is configured to establish the first connection on the first network if the registration on the first network is successful.

57. The terminal according to claim 47, wherein, The first processing unit is configured to perform one of the following: in the event that the first connection is lost, perform at least one of the following: maintain the second connection, release the second connection, reselect the first network, and reselect the second network based on the first information; in the event that the second connection is lost, perform at least one of the following: maintain the first connection, release the first connection, reselect the first network, and reselect the second network based on the first information.

58. The terminal according to claim 57, wherein, The first processing unit is used to release the second connection when the terminal is in an idle state.

59. The terminal according to claim 57, wherein, The first processing unit is used to release the first connection when the terminal is in an idle state.

60. The terminal according to any one of claims 35-59, wherein, The first piece of information is either default or specified by the protocol.

61. The terminal according to any one of claims 35-59, further comprising: The first communication unit is used to receive the first information.

62. A first core network device, comprising: The second communication unit is used to send first information to the terminal, wherein the first information is used by the terminal to select a second network.

63. The first core network device according to claim 62, wherein, The first information includes at least one of the following: one or more Radio Access Technologies (RATs) corresponding to the second connection, the priority of one or more RATs corresponding to the second connection, one or more networks corresponding to the second connection, the priority of one or more networks corresponding to the second connection, one or more combination information corresponding to the second connection, and the priority of one or more combination information corresponding to the second connection, wherein the combination information includes the network and the RAT, and the second connection is established by the terminal under the second network.

64. The first core network device according to claim 63, wherein, The first information includes one of the following: a first association relationship between one or more RATs corresponding to the first connection and one or more RATs corresponding to the second connection; a second association relationship between one or more networks corresponding to the first connection and one or more networks corresponding to the second connection; and a third association relationship between one or more combined information corresponding to the first connection and one or more combined information corresponding to the second connection, wherein the first connection is established by the terminal under the first network.

65. The first core network device according to claim 63 or 64, wherein, The first information includes at least one of the following: one or more RATs corresponding to the first connection, the priority of one or more RATs corresponding to the first connection, one or more networks corresponding to the first connection, the priority of one or more networks corresponding to the first connection, one or more combination information corresponding to the first connection, and the priority of one or more combination information corresponding to the first connection, wherein the combination information includes networks and RATs, and the first connection is established by the terminal under the first network.

66. The first core network device according to claim 65, wherein, The first information is also used by the terminal to select the first network.

67. The first core network device according to any one of claims 62-66, wherein, The second communication unit is used to send a multi-connection enable indication to the terminal, wherein the multi-connection enable indication is used for the terminal to enable the multi-connection function.

68. The first core network device according to claim 67, wherein, The second communication unit is configured to receive a multi-connection disable indication from the terminal, wherein the multi-connection disable indication is configured to instruct the terminal to disable the multi-connection function.

69. A terminal, comprising: A transceiver, a processor, and a memory for storing a computer program, the transceiver for communicating with other devices, and the processor for calling and running the computer program stored in the memory to cause the terminal to perform the method as described in any one of claims 1 to 27.

70. A first core network device, comprising: A transceiver, a processor, and a memory for storing computer programs, the transceiver for communicating with other devices, and the processor for calling and running the computer programs stored in the memory to cause the first core network device to perform the method as described in any one of claims 28 to 34.

71. A chip, comprising: A processor for retrieving and running a computer program from memory, causing a device on which the chip is mounted to perform the method as described in any one of claims 1 to 27 or 28 to 34.

72. A computer-readable storage medium for storing a computer program that, when run by a device, causes the device to perform the method as claimed in any one of claims 1 to 27 or 28 to 34.

73. A computer program product comprising computer program instructions that cause a computer to perform the method as claimed in any one of claims 1 to 27 or 28 to 34.

74. A computer program that causes a computer to perform the method as claimed in any one of claims 1 to 27 or 28 to 34.

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