Control method for communication device and related apparatus

Abstract

The present application provides a control method for a communication device and a related apparatus, which can be applied to the technical field of communications. In the technical solution provided in the present application, a communication device selects a first PLMN as a serving PLMN of a first UE, and selects a second PLMN as a serving PLMN of a second UE. The first PLMN and the second PLMN are different PLMNs, and / or the first PLMN and the second PLMN support dual orientation. The method improves the reliability of accessing the network by the communication device, and / or is conducive to achieving dual directional characteristics of the communication device, thereby implementing transmission of service data of the communication device.

Description

Communication equipment control method and related device

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on February 29, 2024, with application number 202410236310.7 and application name “Control Method and Related Device for Communication Equipment”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of communication technology, and in particular to a control method and related apparatus for communication equipment. Background Art

[0003] The communication system proposes a mobile communication device including two terminals or two subscriber identity modules (SIMs), but does not provide a technical solution for how the mobile communication device coordinates the two terminals or the two SIMs, for example, how to coordinate the selection of a public land mobile network (PLMN) or how to coordinate service orientation. Summary of the Invention

[0004] The present application provides a control method and related apparatus for a communication device, which can select a PLMN for two terminals or two SIMs in the communication device.

[0005] In a first aspect, the present application provides a control method for a communication device, wherein the communication device includes a first UE and a second UE, and the method includes: selecting a first PLMN as a service PLMN for the first terminal; selecting a second PLMN as a service PLMN for the second terminal, wherein the first PLMN and the second PLMN are different PLMNs.

[0006] As an example, the first UE may be UE1 in the communication device shown in FIG. 4 , and the second SIM may be UE2 in the communication device shown in FIG. 4 .

[0007] As another example, the first UE may be UE2 in the communication device shown in FIG. 4 , and the second UE may be UE1 in the communication device shown in FIG. 4 .

[0008] In this method, the serving PLMN of the first UE may be understood as the PLMN that the first UE has already accessed. The serving PLMN of the second UE may be understood as the PLMN that the second UE has already accessed.

[0009] In this method, the first PLMN and the second PLMN selected by the communication device are different. When the network connected to one UE in the communication device is disconnected, the other UE can still be connected to the network, avoiding the situation where both UEs in the communication device are disconnected from the network due to a network failure or connection interruption, which is conducive to improving the reliability of the communication device's access to the network.

[0010] In some possible implementations, the selecting the second PLMN as the service PLMN of the second terminal includes: the DS layer of the communication device receives first information transmitted by a first non-access layer, the first information instructs the first non-access layer to select a first PLMN as the service PLMN of the first terminal, and the first non-access layer is the non-access layer of the first terminal; the DS layer sends the first PLMN to the second non-access layer, and the second non-access layer is the non-access layer of the second terminal; the second non-access layer selects a second PLMN as the service PLMN of the second terminal, and the second PLMN is different from the first PLMN.

[0011] In this implementation, the second NAS layer may select the second PLMN based on the second network selection list.

[0012] Optionally, the second NAS layer may further select a second PLMN based on the first PLMN set, wherein the second PLMN may be a PLMN with the highest priority in the first PLMN set, and the PLMNs in the first PLMN set are different from the first PLMN.

[0013] Optionally, the first PLMN set may be a PLMN in the second network selection list that is different from the first PLMN.

[0014] The second network selection list may be a network selection list corresponding to the second UE. The second network selection list may include at least one PLMN and a priority of the at least one PLMN.

[0015] Optionally, the second network selection list may be configured in advance for the communication device. After receiving the second network selection list, the communication device may store the second network selection list.

[0016] In this implementation, after receiving the first PLMN, the second NAS layer can select the second PLMN based on the first PLMN. This can reduce the number of interactions between the DS layer and the second NAS layer, which is conducive to improving the efficiency of selecting the second PLMN.

[0017] In some possible implementations, the selecting the second PLMN as the service PLMN of the second terminal includes: the DS layer of the communication device receives first information transmitted by a first non-access layer, the first information indicates that the PLMN selected by the first non-access layer for the first terminal is the first PLMN, and the first non-access layer is the non-access layer of the first terminal; the DS layer receives second information transmitted by a second non-access layer, the second information indicates that the PLMN selected by the second non-access layer for the second terminal is the second PLMN, and the second non-access layer is the non-access layer of the second terminal; if the second PLMN and the first PLMN are different PLMNs, transmitting third information to the second non-access layer, the third information indicating that the second PLMN is agreed to be the service PLMN of the second terminal.

[0018] In this method, the PLMN selected by the second NAS layer for the second UE may be a search PLMN or a serving PLMN.

[0019] Optionally, when the PLMN selected by the second NAS layer for the second UE is a search PLMN, the second NAS layer can first select a PLMN with the highest priority as the search PLMN based on the second network selection list, and then transmit the second information to the DS layer. The DS layer determines whether the PLMN selected by the second NAS layer for the second UE is the same PLMN as the first PLMN.

[0020] Optionally, when the PLMN selected by the second NAS layer for the second UE is a serving PLMN, the second NAS layer may first select a PLMN with the highest priority and a successful cell search as a serving PLMN based on the second network selection list, and then transmit the second information to the DS layer. The DS layer determines whether the PLMN selected by the second NAS layer for the second UE is the same PLMN as the first PLMN.

[0021] In this implementation, the DS layer determines whether the PLMN selected by the second NAS layer is the same as the first PLMN. In this way, the second NAS layer does not need to perform this determination process. This not only avoids direct interaction between the first and second NAS layers, but also helps improve the efficiency of the second NAS in selecting the second PLMN.

[0022] In some possible implementations, the selecting the second PLMN as the service PLMN of the second terminal includes: the DS layer of the communication device receives first information transmitted by a first non-access stratum, the first information instructing the first non-access stratum to select the first PLMN as the service PLMN of the first terminal, and the first non-access stratum is the non-access stratum of the first terminal; the DS layer receives second information transmitted by a second non-access stratum, the second information indicates that the PLMN selected by the second non-access stratum for the second terminal is a third PLMN, and the second non-access stratum is the non-access stratum of the second terminal; if the third PLMN and the first PLMN are the same PLMN, the DS layer transmits fourth information to the second non-access stratum, the fourth information indicating that the third PLMN is not agreed to be the service PLMN of the second terminal or instructing the second non-access stratum to reselect a PLMN; and the second non-access stratum selects the second PLMN as the service PLMN of the second terminal according to the fourth information.

[0023] In this implementation, the PLMN selected by the second NAS layer for the second UE may be a search PLMN or a serving PLMN.

[0024] In this implementation, the DS layer determines whether the PLMN selected by the second NAS layer is the same as the first PLMN. In this way, the second NAS layer does not need to perform this determination process. This not only avoids direct interaction between the first and second NAS layers, but also helps improve the efficiency of the second NAS in selecting the second PLMN.

[0025] In some possible implementations, the first PLMN and the second PLMN are PLMNs supporting dual-directionality.

[0026] In this implementation, the communication device can implement the dual-directional feature only when both the first PLMN and the second PLMN selected by the communication device support dual-directional. For example, the communication device can control service direction and service switching processes to complete the transmission of service data.

[0027] In some possible implementations, the method further includes: the DS layer of the communication device sends fifth information to the first non-access layer and the second non-access layer respectively, the fifth information requesting selection of a PLMN that supports dual-direction, the first non-access layer being the non-access layer of the first terminal, and the second non-access layer being the non-access layer of the second terminal; the first non-access layer and the second non-access layer respectively select PLMNs based on the fifth information.

[0028] In this implementation, the PLMN selected by the first NAS layer based on the fifth information may be the PLMN with the highest priority in the first network selection list, the PLMN for which the cell search is successful, and which supports dual-directionality. In this way, the communication device can implement the dual-directionality feature through the first UE to complete the transmission of service data through the first UE.

[0029] Optionally, after receiving the first PLMN, the DS layer may send the fifth information to the second NAS layer.

[0030] Optionally, the fifth information may also include the first PLMN. Based on the fifth information, the second NAS layer may select a PLMN that is different from the first PLMN, has the highest priority, has successfully searched for a cell, and supports dual-directional communication. This allows the communication device to implement dual-directional communication through the second UE, thereby completing service data transmission through the second UE. Furthermore, since the second PLMN is different from the first PLMN, it can prevent both UEs in the communication device from being disconnected from the network due to a network failure or connection interruption.

[0031] In some possible implementations, the method further includes: the DS layer of the communication device receives sixth information transmitted by the second non-access layer, the sixth information indicating whether the second PLMN supports dual-direction, and the second non-access layer is the non-access layer of the second terminal; if the sixth information indicates that the second PLMN supports dual-direction, the DS layer determines to use the second PLMN as the service PLMN of the second terminal; if the sixth information indicates that the second PLMN does not support dual-direction, the DS layer sends seventh information to the second non-access layer, the seventh information indicating that it does not agree to use the second PLMN as the service PLMN of the second terminal or instructs the second non-access layer to select a PLMN that supports dual-direction; the second non-access layer reselects the PLMN based on the seventh information.

[0032] In this implementation, when the second SIM is registered, the second NAS layer may obtain from the core network whether the serving PLMN of the second SIM supports dual-directionality, and then send the sixth information to the DS layer.

[0033] In this implementation, the DS layer can determine whether the second PLMN supports dual-directionality based on the sixth information, which is conducive to obtaining a PLMN that supports dual-directionality and is different from the first PLMN, and thus is conducive to the communication device to realize the dual-directional feature, and can avoid the situation where both UEs in the communication device are disconnected from the network due to a network failure or connection interruption.

[0034] In some possible implementations, the seventh information further includes the first PLMN.

[0035] In this implementation, the second NAS layer can reselect a PLMN that supports dual-directionality and is different from the first PLMN based on the seventh information, which is conducive to the communication device to realize the dual-directional feature, and can avoid the situation where both UEs in the communication device are disconnected from the network due to a network failure or connection interruption.

[0036] In some possible implementations, the method further includes: determining a first target terminal, where the first target terminal is one of the first terminal and the second terminal; and transmitting a target service of the communication device based on the first target terminal.

[0037] In this implementation, the communication device selects the first target UE to transmit the target service to meet the target service requirements.

[0038] In some possible implementations, determining the first target terminal includes: obtaining a service orientation policy, the service orientation policy including at least one service and the PLMN and / or RAT preferentially associated with each service in the at least one service, the at least one service including the target service; obtaining first access information and second access information, the first access information including the PLMN and / or RAT accessed by the first terminal, and the second access information including the PLMN and / or RAT accessed by the second terminal; determining the first target terminal based on the first access information, the second access information, and the service orientation policy, the PLMN accessed by the first target terminal being the PLMN preferentially associated with the target service, and / or the RAT accessed by the first target terminal being the RAT preferentially associated with the target service.

[0039] In this implementation, the communication device may obtain the service orientation policy through the first UE or the second UE. As an example, when the first UE or the second UE registers, the service orientation policy may be obtained from the network.

[0040] As an example, assuming that the service orientation policy includes that the target service is preferentially transmitted through the first PLMN, and the first UE accesses the first PLMN and the second UE accesses the second PLMN, the communication device may determine the first UE as the first target UE.

[0041] In this implementation, the communication device may transmit the target service according to the PLMN preferentially associated with the target service to meet the requirements of the target service.

[0042] In some possible implementations, determining the first target terminal includes: the DS layer of the communication device obtains a service orientation policy from a first non-access stratum or a second non-access stratum, the service orientation policy includes at least one service and a PLMN and / or RAT preferentially associated with each service in the at least one service, the at least one service includes the target service, the first non-access stratum is the non-access stratum of the first terminal, and the second non-access stratum is the non-access stratum of the second terminal; the DS layer obtains first access information from the first non-access stratum or the first access stratum, the first access information includes the PLMN and / or RAT accessed by the first terminal, and the first access stratum is the access stratum of the first terminal; the DS layer obtains second access information from the second non-access stratum or the second access stratum, the second access information includes the PLMN and / or RAT accessed by the second terminal, and the second access stratum is the access stratum of the second terminal; the DS layer determines the first target terminal based on the first access information, the second access information, and the service orientation policy, the PLMN accessed by the first target terminal is the PLMN preferentially associated with the target service, and / or the RAT accessed by the first target terminal is the RAT preferentially associated with the target service.

[0043] In this implementation, the DS layer may obtain the service orientation policy through the first NAS layer or the second NAS layer.

[0044] As an example, when the first UE registers, the first UE may obtain the service orientation policy through the first NAS layer, and then the first NAS layer sends the service orientation policy to the DS layer. After receiving the service orientation policy, the DS layer stores the service orientation policy.

[0045] As another example, when the second UE registers, the second UE may obtain the service orientation policy through the second NAS layer, and then the second NAS layer sends the service orientation policy to the DS layer, and the DS layer stores the service orientation policy after receiving the service orientation policy.

[0046] As an example, assuming that the service orientation policy includes that the target service is preferentially transmitted through the first PLMN, and the first UE accesses the first PLMN and the second UE accesses the second PLMN, the DS layer of the communication device can determine the first UE as the first target UE.

[0047] In this implementation, the DS layer of the communication device may transmit the target service according to the PLMN to which the target service is preferentially associated, so as to meet the requirements of the target service.

[0048] In some possible implementations, the method further includes: transmitting the target service through a second target terminal according to a connection state of the first target terminal, where the second target terminal is a terminal other than the first target terminal between the first terminal and the second terminal.

[0049] In this implementation, the first target UE may be a UE used by the communication device to transmit the target service.

[0050] As an example, the first target UE may be a first UE, and correspondingly, the second target UE may be a second UE.

[0051] As another example, the first target UE may be the second UE. Correspondingly, the second target UE may be the first UE.

[0052] Optionally, the first target UE may be a UE selected for the target service when the communication device controls service direction.

[0053] In this implementation, the communication device may determine the connection status of the first target UE based on the first target UE. The connection status of the first target UE may include any one or more of the following: an air interface signal value of the first target UE, or a measurement value between the first target UE and a UPF network element.

[0054] When the communication device transmits the target service based on the first target UE, the air interface signal value of the first target UE is lower than the preset threshold, and / or the measurement value between the first target UE and the UPF network element is lower than the preset threshold, the communication device can determine to transmit the target service through the second target UE.

[0055] Optionally, when the air interface signal value of the second target UE is higher than a preset threshold, the communication device may also determine to transmit the target service through the second target UE.

[0056] In this implementation, after the communication device determines to transmit the target service through the second target UE, it can establish a session or perform session switching based on the second target UE.

[0057] In this implementation method, the air interface signal value of the UE selected by the communication device for transmitting the target service meets the preset threshold requirement, or the measurement value between the UE selected by the communication device for transmitting the target service and the UPF network element meets the preset threshold, which is conducive to ensuring the transmission quality of the service data.

[0058] In some possible implementations, the method further includes: the DS layer of the communication device obtains the connection status of the first target terminal from the non-access layer of the first target terminal or the access layer of the first target terminal; the DS layer of the communication device determines to transmit the target service based on the second target terminal according to the connection status of the first target terminal, and the second target terminal is a terminal other than the first target terminal between the first terminal and the second terminal.

[0059] In this implementation, the first target UE may be a UE used by the communication device to transmit the target service.

[0060] As an example, the first target UE may be the first UE, the NAS layer of the first target UE may be the first NAS layer, and the AS layer of the first target UE may be the first AS layer. Correspondingly, the second target UE may be the second UE.

[0061] As another example, the first target UE may be the second UE, the NAS layer of the first target UE may be the second NAS layer, the AS layer of the first target UE may be the second AS layer. Accordingly, the second target UE may be the first UE.

[0062] Optionally, the first target UE may be a UE selected for the target service when the communication device controls service direction.

[0063] In this implementation, the connection status of the first target UE may include any one or more of the following: the air interface signal value of the first target UE, or the measurement value between the first target UE and the UPF network element.

[0064] When the communication device transmits the target service based on the first target UE, the air interface signal value of the first target UE is lower than the preset threshold, and / or the measurement value between the first target UE and the UPF network element is lower than the preset threshold, the DS layer of the communication device can determine to transmit the target service through the second target UE.

[0065] Optionally, when the air interface signal value of the second target UE is higher than a preset threshold, the DS layer of the communication device may also determine to transmit the target service through the second target UE.

[0066] In this implementation, after the DS layer of the communication device determines to transmit the target service through the second target UE, it can establish a session or perform session switching based on the second target UE.

[0067] In this implementation method, the air interface signal value of the UE selected by the DS layer of the communication device for transmitting the target service meets the preset threshold requirement, or the measurement value between the UE and the UPF network element selected by the DS layer of the communication device for transmitting the target service meets the preset threshold, which is conducive to ensuring the transmission quality of the service data.

[0068] In some possible implementations, the communication device is in a bi-directional mode or the communication device is authorized for bi-directional operation.

[0069] Optionally, the communication device may determine whether to be in the bi-directional mode based on a user instruction.

[0070] Optionally, the communication device may determine whether the dual-directional operation is authorized by receiving authorization information, and the authorization information may indicate that the dual-directional operation is authorized.

[0071] In this implementation, the communication device can select different PLMNs and / or select a PLMN that supports dual-directional operation for the first UE and the second UE only when the communication device is in dual-directional mode or the communication device is authorized for dual-directional operation, thereby realizing the dual-directional feature of the communication device and avoiding the situation where both UEs in the communication device are disconnected from the network due to a network failure or connection interruption.

[0072] In some possible implementations, the first terminal is a primary terminal in the communication device, and / or the second terminal is a secondary terminal in the communication device.

[0073] In other words, the priority of the first UE is higher than the priority of the second UE.

[0074] Optionally, the priorities of the first UE and the second UE may also be configured in advance. As an example, a user may set the priorities of the first UE and the second UE in a communication device.

[0075] Since the business data processed by the primary terminal is usually more critical than the business data processed by the secondary terminal, determining the network of the primary terminal first is beneficial to improving the transmission efficiency of the business data with higher criticality.

[0076] In a second aspect, the present application provides a control method for a communication device, wherein the communication device includes a first terminal and a second terminal, and the method includes: selecting a first PLMN as a service PLMN for the first terminal; selecting a second PLMN as a service PLMN for the second terminal, wherein the first PLMN and the second PLMN are PLMNs that support dual-directionality.

[0077] In this implementation, the communication device can implement the dual-directional feature only when both the first PLMN and the second PLMN selected by the communication device support dual-directional. For example, the communication device can control service direction and service switching processes to complete the transmission of service data.

[0078] In some possible implementations, the method further includes: receiving, through the first terminal, information that the first PLMN supports dual-directionality; and receiving, through the second terminal, information that the second PLMN supports dual-directionality.

[0079] For example, when a first UE registers, the NAS layer of the first UE may receive information indicating that the first PLMN supports dual-directional orientation. When a second UE registers, the NAS layer of the second UE may receive information indicating that the second PLMN supports dual-directional orientation.

[0080] In this implementation, the communication device can select the first PLMN as the PLMN of the first UE based on the information that the first PLMN supports dual-direction, and select the second PLMN as the PLMN of the second UE based on the information that the second PLMN supports dual-direction. In this way, the service PLMNs selected by the communication device for the first UE and the second UE both support dual-direction, thereby enabling the communication device to implement dual-direction characteristics. For example, the communication device can control service direction and service switching processes to complete the transmission of service data.

[0081] In some possible implementations, the selecting of the first PLMN as the service PLMN of the first terminal includes: the DS layer of the communication device sends a first request message to the first non-access layer, the first request message requests the selection of a PLMN that supports dual-direction, the first non-access layer being the non-access layer of the first terminal; the first non-access layer selects the first PLMN as the service PLMN of the first terminal according to the first request message.

[0082] In this implementation, after receiving the first request information, the first NAS layer may select a first PLMN according to the first network selection list. The first PLMN is the PLMN with the highest priority in the first network selection list, has a successful cell search, and supports dual-directionality.

[0083] The first network selection list may be a network selection list corresponding to the first UE. The first network selection list may include at least one PLMN and a priority of the at least one PLMN.

[0084] Optionally, the first NAS layer may first determine one or more PLMNs supporting dual-directionality from the first network selection list, and then determine the PLMN with the highest priority among the one or more PLMNs as the first PLMN.

[0085] In this implementation, the DS layer of the communication device can determine the PLMN with the highest priority in the first network selection list, the successful cell search and support for dual-directionality as the service PLMN of the first UE, so that the communication device can implement the dual-directional feature through the first UE to complete the transmission of service data through the first UE.

[0086] In addition, after receiving the first request message, the first NAS layer can select the first PLMN according to the first request message. This can reduce the number of interactions between the DS layer and the first NAS layer, which is conducive to improving the efficiency of selecting the first PLMN.

[0087] In some possible implementations, the selecting of the first PLMN as the service PLMN of the first terminal includes: the DS layer of the communication device receives first network information transmitted by a first non-access layer, the first network information indicates that the PLMN selected by the first non-access layer for the first terminal is the first PLMN, and the first non-access layer is the non-access layer of the first terminal; if the first PLMN supports a dual-directional function, the DS layer sends first indication information to the first non-access layer, the first indication information indicating that the first PLMN is agreed to be the service PLMN of the first terminal.

[0088] Optionally, the first network information may further include indication information of whether the first PLMN supports dual-directional communication.

[0089] In this implementation, the PLMN selected by the first NAS layer for the first UE may be a search PLMN or a serving PLMN.

[0090] Optionally, when the PLMN selected by the first NAS layer for the first UE is a search PLMN, the first NAS layer may select the PLMN with the highest priority as the first PLMN based on the first network selection list. If the first PLMN supports dual-directionality, the DS layer may send a first indication message to the first NAS layer. After receiving the first indication message, the first NAS layer may perform a cell search based on the first PLMN and send an indication message to the DS layer as to whether the first PLMN cell search is successful. If the first PLMN cell search is successful, the DS layer may determine that the first PLMN is the serving PLMN for the first UE; if the first PLMN cell search fails, the DS layer may instruct the first NAS layer to reselect a PLMN that supports dual-directionality.

[0091] Optionally, when the PLMN selected by the first NAS layer for the first UE is a serving PLMN, the first NAS layer may select, based on the first network selection list, a PLMN with the highest priority and a successful cell search as the first PLMN. If the first PLMN supports dual-directional, the DS layer may send first indication information to the first NAS layer.

[0092] In this implementation, the DS layer determines whether the first NAS layer needs to select a PLMN that supports dual-directionality. In this way, the first NAS layer does not need to perform this judgment process, which not only avoids the influence of the PLMN selection logic of the first NAS layer, but also helps to improve the efficiency of the first NAS in selecting the first PLMN.

[0093] In some possible implementations, the selecting of the first PLMN as the service PLMN of the first terminal includes: the DS layer of the communication device receives second network information transmitted by the first non-access layer, the second network information indicates that the PLMN selected by the first non-access layer for the first terminal is the fourth PLMN, and the first non-access layer is the non-access layer of the first terminal; if the fourth PLMN does not support the dual-directional function, the DS layer sends second indication information to the first non-access layer, the second indication information indicates that the fourth PLMN is not agreed to be the service PLMN of the first terminal or instructs the first non-access layer to select a PLMN that supports dual-directionality; the first non-access layer selects the first PLMN as the service PLMN of the first terminal according to the second indication information.

[0094] Optionally, the first network information may further include indication information of whether the fourth PLMN supports dual-directionality.

[0095] In this implementation, the PLMN selected by the first NAS layer for the first UE may be a search PLMN or a serving PLMN.

[0096] In this implementation, the DS layer may obtain information that the fourth PLMN does not support dual-directional communication from the first NAS layer.

[0097] Optionally, when the PLMN selected by the first NAS layer for the first UE is a search PLMN, the first NAS layer may select the PLMN with the highest priority as the fourth PLMN based on the first network selection list. If the fourth PLMN does not support dual-directional positioning, the DS layer may send a second indication message to the first NAS layer. After receiving the second indication message, the first NAS layer reselects a PLMN that supports dual-directional positioning.

[0098] Optionally, when the PLMN selected by the first NAS layer for the first UE is a serving PLMN, the first NAS layer may select, based on the first network selection list, a PLMN with the highest priority and a successful cell search as a fourth PLMN. If the fourth PLMN does not support dual-directional direction, the DS layer may send a second indication message to the first NAS layer.

[0099] In this implementation, the DS layer determines whether the first NAS layer needs to select a PLMN that supports dual-directionality. In this way, the first NAS layer does not need to perform this judgment process, which not only avoids the influence of the PLMN selection logic of the first NAS layer, but also helps to improve the efficiency of the first NAS in selecting the first PLMN.

[0100] In some possible implementations, the first PLMN and the second PLMN are different PLMNs.

[0101] In this implementation, the first PLMN and the second PLMN selected by the communication device are different. When the network connected to one UE in the communication device is disconnected, the other UE can still be connected to the network, avoiding the situation where both UEs in the communication device are disconnected from the network due to a network failure or connection interruption, which is beneficial to improving the reliability of the communication device's access to the network.

[0102] In some possible implementations, the method further includes: the DS layer of the communication device determines whether the first PLMN and the second PLMN are different PLMNs; if the first PLMN and the second PLMN are different PLMNs, the DS layer determines to select the first PLMN as the service PLMN of the first terminal, and determines to select the second PLMN as the service PLMN of the second terminal; if the first PLMN and the second PLMN are the same PLMN, the DS layer sends third indication information to the first non-access layer or the second non-access layer, and the third indication information is used to indicate reselection of the PLMN.

[0103] In this implementation, the DS layer may send the third indication information to the first NAS layer or the second NAS layer according to the priority of the first UE and the second UE. For example, the DS layer may send the third indication information to the NAS layer of the UE with lower priority.

[0104] Assuming that the first UE is a primary terminal and the second UE is a secondary terminal, or in other words, the priority of the first UE is higher than that of the second UE, the DS layer may send third indication information to the second NAS layer.

[0105] In this implementation, the first PLMN and the second PLMN selected by the communication device are different. When the network connected to one UE in the communication device is disconnected, the other UE can still be connected to the network, avoiding the situation where both UEs in the communication device are disconnected from the network due to a network failure or connection interruption, which is beneficial to improving the reliability of the communication device's access to the network.

[0106] In some possible implementations, the method further includes: determining a first target terminal, where the first target terminal is one of the first terminal and the second terminal; and transmitting a target service of the communication device based on the first target terminal.

[0107] In some possible implementations, determining the first target terminal includes: obtaining a service orientation policy, the service orientation policy including at least one service and the PLMN and / or RAT preferentially associated with each service in the at least one service, the at least one service including the target service; obtaining first access information and second access information, the first access information including the PLMN and / or RAT accessed by the first terminal, and the second access information including the PLMN and / or RAT accessed by the second terminal; determining the first target terminal based on the first access information, the second access information, and the service orientation policy, the PLMN accessed by the first target terminal being the PLMN preferentially associated with the target service, and / or the RAT accessed by the first target terminal being the RAT preferentially associated with the target service.

[0108] In some possible implementations, determining the first target terminal includes: the DS layer of the communication device obtains a service orientation policy from a first non-access stratum or a second non-access stratum, the service orientation policy includes at least one service and a PLMN and / or RAT preferentially associated with each service in the at least one service, the at least one service includes the target service, the first non-access stratum is the non-access stratum of the first terminal, and the second non-access stratum is the non-access stratum of the second terminal; the DS layer obtains first access information from the first non-access stratum or the first access stratum, the first access information includes the PLMN and / or RAT accessed by the first terminal, and the first access stratum is the access stratum of the first terminal; the DS layer obtains second access information from the second non-access stratum or the second access stratum, the second access information includes the PLMN and / or RAT accessed by the second terminal, and the second access stratum is the access stratum of the second terminal; the DS layer determines the first target terminal based on the first access information, the second access information, and the service orientation policy, the PLMN accessed by the first target terminal is the PLMN preferentially associated with the target service, and / or the RAT accessed by the first target terminal is the RAT preferentially associated with the target service.

[0109] In some possible implementations, the method further includes: transmitting the target service through a second target terminal according to a connection state of the first target terminal, where the second target terminal is a terminal other than the first target terminal between the first terminal and the second terminal.

[0110] In some possible implementations, the method further includes: the DS layer of the communication device obtains the connection status of the first target terminal from the non-access layer of the first target terminal or the access layer of the first target terminal; the DS layer determines to transmit the target service based on the second target terminal according to the connection status of the first target terminal, and the second target terminal is a terminal other than the first target terminal between the first terminal and the second terminal.

[0111] In some possible implementations, the communication device is in a bi-directional mode or the communication device is authorized for bi-directional operation.

[0112] It can be understood that the effects that can be obtained by some possible implementation methods of the second aspect can be referred to the description of the first aspect and will not be repeated here.

[0113] In a third aspect, the present application provides a control method for a communication device, wherein the communication device includes a first terminal and a second terminal, and the method further includes: determining a first target terminal, which is one of the first terminal and the second terminal; and transmitting a target service of the communication device based on the first target terminal.

[0114] In some possible implementations, determining the first target terminal includes: obtaining a service orientation policy, the service orientation policy including at least one service and the PLMN and / or RAT preferentially associated with each service in the at least one service, the at least one service including the target service; obtaining first access information and second access information, the first access information including the PLMN and / or RAT accessed by the first terminal, and the second access information including the PLMN and / or RAT accessed by the second terminal; determining the first target terminal based on the first access information, the second access information, and the service orientation policy, the PLMN accessed by the first target terminal being the PLMN preferentially associated with the target service, and / or the RAT accessed by the first target terminal being the RAT preferentially associated with the target service.

[0115] In some possible implementations, determining the first target terminal includes: the DS layer of the communication device obtains a service orientation policy from a first non-access stratum or a second non-access stratum, the service orientation policy includes at least one service and a PLMN and / or RAT preferentially associated with each service in the at least one service, the at least one service includes the target service, the first non-access stratum is the non-access stratum of the first terminal, and the second non-access stratum is the non-access stratum of the second terminal; the DS layer obtains first access information from the first non-access stratum or the first access stratum, the first access information includes the PLMN and / or RAT accessed by the first terminal, and the first access stratum is the access stratum of the first terminal; the DS layer obtains second access information from the second non-access stratum or the second access stratum, the second access information includes the PLMN and / or RAT accessed by the second terminal, and the second access stratum is the access stratum of the second terminal; the DS layer determines the first target terminal based on the first access information, the second access information, and the service orientation policy, the PLMN accessed by the first target terminal is the PLMN preferentially associated with the target service, and / or the RAT accessed by the first target terminal is the RAT preferentially associated with the target service.

[0116] In some possible implementations, the method further includes: transmitting the target service through a second target terminal according to a connection state of the first target terminal, where the second target terminal is a terminal other than the first target terminal between the first terminal and the second terminal.

[0117] In some possible implementations, the method further includes: the DS layer of the communication device obtains the connection status of the first target terminal from the non-access layer of the first target terminal or the access layer of the first target terminal; the DS layer determines to transmit the target service based on the second target terminal according to the connection status of the first target terminal, and the second target terminal is a terminal other than the first target terminal between the first terminal and the second terminal.

[0118] In some possible implementations, the communication device is in a bi-directional mode or the communication device is authorized for bi-directional operation.

[0119] It can be understood that the effects that can be obtained in the third aspect can be referred to the description of the first aspect and will not be repeated here.

[0120] In a fourth aspect, the present application provides a control device for a communication device, which can be used for the communication device of the first aspect. The control device of the communication device can be a communication device, or a device in a communication device (for example, a chip, a chip system, or a circuit), or can be a logic module or software that can realize all or part of the functions of the communication device. In one possible implementation, a module or unit for realizing the method in the first aspect and any possible implementation of the first aspect is included. For example, it can include a module or unit that corresponds one-to-one to the method / operation / step / action described in the first aspect, and the module or unit can be a hardware circuit, or software, or a combination of a hardware circuit and software. Optionally, each module or unit can realize the corresponding function by executing a computer program.

[0121] In a fifth aspect, the present application provides a control device for a communication device, which can be used for the communication device of the second aspect. The control device of the communication device can be a communication device, or a device in a communication device (for example, a chip, a chip system, or a circuit), or can be a logic module or software that can realize all or part of the functions of the communication device. In one possible implementation, a module or unit for realizing the method in the second aspect and any possible implementation of the second aspect is included. For example, it can include a module or unit that corresponds one-to-one to the method / operation / step / action described in the second aspect, and the module or unit can be a hardware circuit, or software, or a combination of a hardware circuit and software. Optionally, each module or unit can realize the corresponding function by executing a computer program.

[0122] In a sixth aspect, the present application provides a control device for a communication device, which can be used for the communication device of the third aspect. The control device of the communication device can be a communication device, or a device in a communication device (for example, a chip, a chip system, or a circuit), or can be a logic module or software that can realize all or part of the functions of the communication device. In one possible implementation, a module or unit for realizing the method in the third aspect and any possible implementation of the third aspect is included. For example, it can include a module or unit that corresponds one-to-one to the method / operation / step / action described in the third aspect, and the module or unit can be a hardware circuit, or software, or a combination of a hardware circuit and software. Optionally, each module or unit can realize the corresponding function by executing a computer program.

[0123] In the seventh aspect, the present application provides a control device of a communication device, comprising a processor, for causing the device to execute a computer program (or computer executable instructions) stored in a memory, and / or through a logic circuit, a method as in any one of the first to third aspects and any possible implementation thereof.

[0124] In a possible implementation, the device further includes a memory.

[0125] In one possible implementation, the processor and the memory are integrated together.

[0126] In another possible implementation, the memory is located outside the communication device.

[0127] In one possible implementation, the control device of the communication device further includes a communication interface, which is used for the control device of the communication device to communicate with other devices, such as sending or receiving data and / or signals. Exemplarily, the communication interface can be a transceiver, circuit, bus, module, or other type of communication interface.

[0128] In an eighth aspect, the present application provides a computer-readable storage medium storing a computer program or instruction for execution by a control device of a communication device. When the computer program or instruction runs on the control device of the communication device, the method described in any one of the first to third aspects and any possible implementation method thereof is implemented.

[0129] In a ninth aspect, the present application provides a computer program product comprising instructions, which, when executed on a control device of a communication device, enables the method described in any one of the first to third aspects and any possible implementation thereof to be implemented.

[0130] In a tenth aspect, the present application provides a communication system, comprising a communication device. The communication device is configured to execute the method described in the first aspect and any possible implementation of the first aspect, or the method described in the second aspect and any possible implementation of the second aspect, or the method described in the third aspect and any possible implementation of the third aspect.

[0131] It can be understood that the effects obtainable in the fourth to tenth aspects can be referred to the descriptions in the first and second aspects and will not be elaborated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0132] FIG1 is a schematic diagram of a communication system applicable to an embodiment of the present application;

[0133] FIG2 is a schematic diagram of a 5G communication system provided by an embodiment of the present application;

[0134] FIG3 is a flow chart of a method for UE to select a network according to a network selection list;

[0135] FIG4 is a schematic diagram of a communication device provided in an embodiment of the present application;

[0136] FIG5 is a schematic diagram of another communication device provided in an embodiment of the present application;

[0137] FIG6 is a schematic diagram of the structure of a communication device provided in an embodiment of the present application;

[0138] FIG7 is a flow chart of a control method for a communication device provided in an embodiment of the present application;

[0139] FIG8 is a schematic diagram of a first network selection list provided in one embodiment of the present application;

[0140] FIG9 is a flow chart of a method for a communication device to select a second PLMN as a serving PLMN for a second SIM based on a second NAS layer according to an embodiment of the present application;

[0141] FIG10 is a schematic flow chart of a method for a communication device to select a second PLMN as a serving PLMN for a second UE based on a DS layer according to an embodiment of the present application;

[0142] FIG11 is a schematic flow chart of a method for a communication device to select a second PLMN as a serving PLMN for a second UE based on a DS layer according to another embodiment of the present application;

[0143] FIG12 is a flow chart of a method for controlling service orientation by a communication device according to an embodiment of the present application;

[0144] FIG13 is a schematic diagram of a first user interface of a communication device provided by one embodiment of the present application;

[0145] FIG14 is a schematic diagram of a second user interface of a communication device provided by one embodiment of the present application;

[0146] FIG15 is a flow chart of a control method for a communication device according to another embodiment of the present application;

[0147] FIG16 is a schematic flow chart of a method for a communication device to select a first PLMN as a serving PLMN for a first UE according to an embodiment of the present application;

[0148] FIG17 is a schematic flow chart of a method for a communication device to select a first PLMN as a serving PLMN for a first UE according to another embodiment of the present application;

[0149] FIG18 is a schematic flow chart of a method for a communication device to select a first PLMN as a serving PLMN for a first UE according to another embodiment of the present application;

[0150] FIG19 is a schematic structural diagram of a control device for a communication device according to an embodiment of the present application;

[0151] FIG20 is a schematic structural diagram of a control device of a communication device provided in another embodiment of the present application. DETAILED DESCRIPTION

[0152] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application.

[0153] To facilitate a clear description of the technical solutions of the embodiments of the present application, in the embodiments of the present application, words such as "first" and "second" are used to distinguish between identical or similar items with substantially the same functions and effects. For example, the first information and the second information are merely used to distinguish different information and do not limit their order. Those skilled in the art will understand that words such as "first" and "second" do not limit the quantity or execution order, and words such as "first" and "second" do not necessarily limit differences.

[0154] In the embodiments of the present application, "at least one" refers to one or more, and "more" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: the existence of A alone, the existence of A and B at the same time, and the existence of B alone, where A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. "At least one of the following items" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, at least one of a, b and (or) c can represent: a, b, c; a and b; a and c; b and c; or a and b and c. Where a, b, c can be single or multiple.

[0155] The technical solution of the present application can be applied to wireless mobile cellular networks, including fifth-generation (5G) communication systems, such as 5G new radio (NR) communication systems, and various communication systems evolved after 5G, such as sixth-generation (6G) communication systems. The method provided in the embodiment of the present application can also be applied to wireless WiFi systems, long-range LoRa systems, or Internet of Vehicles systems. The method provided in the embodiment of the present application can also be applied to satellite communication systems. The satellite communication system can be integrated with the above-mentioned communication system, which is not limited by the present application.

[0156] Below, the embodiments of the present application are described in detail with reference to the accompanying drawings.

[0157] To facilitate understanding of the embodiments of the present application, a communication system applicable to the embodiments of the present application is first described with reference to FIG1. ​​As shown in FIG1, the communication system 100 may include at least one network device (such as 110a and 110b in FIG1) and may also include at least one terminal (such as 120a to 120j in FIG1).

[0158] Among them, the network equipment may include wireless access network (RAN) equipment and core network equipment. The terminal may be connected to the wireless access network equipment wirelessly, and the wireless access network equipment may be connected to the core network equipment wirelessly or by wire. The core network equipment and the wireless access network equipment may be independent and different physical devices, or the functions of the core network equipment and the logical functions of the wireless access network equipment may be integrated into the same physical device, or a physical device may integrate some functions of the core network equipment and some functions of the wireless access network equipment. Terminals and wireless access network equipment may be connected to each other by wire or wirelessly. Figure 1 is only a schematic diagram. The communication system may also include other network equipment, such as wireless relay equipment and wireless backhaul equipment, which are not shown in Figure 1.

[0159] A terminal can also be referred to as a terminal device, user equipment (UE), mobile station (MS), mobile terminal (MT), or a device that provides voice or data connectivity to users. It can also be an IoT device. For example, terminal devices include handheld devices with wireless connectivity, in-vehicle devices, etc. Currently, terminal devices may include: mobile phones, tablet computers, laptop computers, PDAs, mobile internet devices (MIDs), wearable devices (such as smart watches, smart bracelets, pedometers, smart glasses, etc.), vehicle-mounted devices (such as cars, bicycles, electric vehicles, airplanes, ships, trains, high-speed trains, etc.), satellite terminals, virtual reality (VR) devices, augmented reality (AR) devices, smart point of sale (POS) machines, customer-premises equipment (CPE), light UEs, reduced capability UEs (REDCAP UEs), wireless terminals in industrial control, smart home devices (such as refrigerators, televisions, air conditioners, and electricity meters), intelligent robots, robotic arms, workshop equipment, wireless terminals in unmanned driving, wireless terminals in telemedicine, wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in smart cities, wireless terminals in smart homes, and flying devices (such as intelligent robots, hot air balloons, drones, and airplanes). The terminal device can also be a vehicle device, such as a complete vehicle device, an onboard module, an onboard chip, an onboard unit (OBU), or a telematics box (T-BOX). The terminal device can also be a roadside unit (RSU). The terminal device can also be other devices with terminal functions, for example, a device that functions as a terminal in D2D communication.

[0160] In the embodiment of the present application, the device for realizing the function of the terminal may be a terminal, or a device that can support the terminal to realize the function, such as a chip system, a communication module, or a modem, etc., and the device can be installed in the terminal. In the embodiment of the present application, the chip system may be composed of chips, or may include chips and other discrete devices. In the technical solution provided in the embodiment of the present application, the device for realizing the function of the terminal is a terminal, and the terminal is a UE as an example to describe the technical solution provided in the embodiment of the present application. The embodiment of the present application does not limit the specific technology and specific device form adopted by the terminal.

[0161] A radio access network device may be a device with wireless transceiver functions. The radio access network device may be a device that provides wireless communication function services, typically located on the network side, and may include but is not limited to: a next-generation base station (gNodeB, gNB) in a 5G communication system, a next-generation base station in a sixth-generation (6G) mobile communication system, a base station in a future mobile communication system, or an access node in a WiFi system, an evolved node B (eNB) in a long-term evolution (LTE) system, a radio network controller (RNC), a home base station (e.g., home evolved NodeB, or home Node B, HNB), a baseband unit (BBU), a transmission reception point (TRP), a transmitting point (TP), etc.

[0162] The radio access network equipment provides services for a cell. The user equipment communicates with the base station through the transmission resources used by the cell. The cell can be the cell corresponding to the base station. The cell can belong to a macro base station or a base station corresponding to a small cell. The small cells here can include: metro cells, micro cells, pico cells, femto cells, etc.

[0163] The wireless access network device can also be a device that acts as a base station in device-to-device (D2D) communication, vehicle-to-vehicle communication, drone communication, and machine communication. Optionally, the wireless access network device can be a satellite, a macro base station, a micro base station or an indoor station, a relay node or a donor node, a device that provides wireless communication services to user devices, a wireless controller in the cloud radio access network (CRAN) scenario, a server, a relay station, a vehicle or vehicle-mounted device, a wearable device, and a network device in a future evolution network. For example, the wireless access network device in vehicle to everything (V2X) technology can be a road side unit (RSU).

[0164] In another possible scenario, multiple radio access network devices collaborate to assist the terminal in achieving wireless access, and different radio access network devices respectively implement part of the functions of the base station. For example, the radio access network device can be a centralized unit (CU), a distributed unit (DU), a CU-control plane (CP), a CU-user plane (UP), or a radio unit (RU). The CU and DU can be set separately, or can also be included in the same network element, such as a BBU. The RU can be included in a radio frequency device or a radio frequency unit, such as a remote radio unit (RRU), an active antenna unit (AAU), or a remote radio head (RRH). It can be understood that the radio access network device can be a CU node, a DU node, or a device including a CU node and a DU node. In addition, the CU can be divided into a network device in the radio access network device, or the CU can be divided into a network device in the core network device, which is not limited here.

[0165] In different systems, CU (or CU-CP and CU-UP), DU or RU may also have different names, but those skilled in the art can understand their meanings. For example, in an open radio access network (O-RAN) system, CU may also be called O-CU (open CU), DU may also be called O-DU, CU-CP may also be called O-CU-CP, CU-UP may also be called O-CU-UP, and RU may also be called O-RU. For the convenience of description, this application uses CU, CU-CP, CU-UP, DU and RU as examples for description. Any unit of CU (or CU-CP, CU-UP), DU and RU in this application can be implemented by a software module, a hardware module, or a combination of a software module and a hardware module.

[0166] In the embodiments of the present application, the form of the wireless access network device is not limited. The device used to implement the functions of the wireless access network device can be the wireless access network device; it can also be a device that supports the wireless access network device to implement the functions, such as a chip system. The device can be installed in the wireless access network device or used in conjunction with the wireless access network device.

[0167] In this application, the number of wireless access network devices and terminals may not be limited. For example, the number of wireless access network devices may be at least one, and each of the at least one wireless access network devices may be connected to at least one terminal.

[0168] In this application, wireless access network devices and terminals can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; can also be deployed on water; and can also be deployed in the air on aircraft, balloons, and satellites. The embodiments of this application do not limit the application scenarios of wireless access network devices and terminals.

[0169] The embodiments of the present application can be applied to downlink signal transmission, uplink signal transmission, and device-to-device (D2D) signal transmission. For downlink signal transmission, the transmitting device is a wireless access network device, and the corresponding receiving device is a terminal. For uplink signal transmission, the transmitting device is a terminal, and the corresponding receiving device is a wireless access network device. For D2D signal transmission, the transmitting device is a terminal, and the corresponding receiving device is also a terminal. The embodiments of the present application do not limit the direction of signal transmission.

[0170] The wireless access network device and the terminal, as well as the terminals, can communicate through the authorized spectrum, through the unlicensed spectrum, or through both the authorized spectrum and the unlicensed spectrum. The wireless access network device and the terminal, as well as the terminals, can communicate through the spectrum below 6G, through the spectrum above 6G, or through both the spectrum below 6G and the spectrum above 6G. The embodiments of the present application do not limit the spectrum resources used between the wireless access network device and the terminal.

[0171] In this application, the core network equipment is mainly used to provide terminal connection, manage terminals and carry out business operations. It can serve as a bearer network to provide an interface to the external network to process and distribute business across the entire network.

[0172] Next, this application will take the 5G communication system as an example to further introduce the communication system architecture of this application. As shown in Figure 2, the 5G communication system includes multiple network function entities, such as UE, (R)AN, access and mobility management function (AMF) network element, session management function (SMF) network element, policy control function (PCF) network element, network repository function (NRF) network element, user plane function (UPF) network element, unified data management (UDM) network element, authentication server function (AUSF) network element, network exposure function (NEF) network element, application function (AF) network element, network slice selection function (NSSF) network element and data network (DN), etc.

[0173] Among them, UE, (R)AN, UPF and DN are generally referred to as data plane network function entities. The user's data traffic can be transmitted through the protocol data unit (PDU) session established between the UE and DN, and the transmission will pass through the two network function entities (R)AN and UPF; the other parts are called control plane network functions and entities, which are mainly responsible for functions such as authentication and authorization, registration management, session management, mobility management and policy control, so as to achieve reliable and stable transmission of user layer traffic.

[0174] The user plane is used to carry service data, and the control plane is used to carry signaling messages.

[0175] The AMF network element belongs to the core network element and is mainly responsible for signaling processing, such as access control, mobility management, attachment and detachment, and gateway selection. When the AMF network element provides services for a session in a terminal device, it will provide control plane storage resources for the session to store the session identifier and the SMF network element identifier associated with the session identifier.

[0176] The SMF network element is mainly responsible for user plane network element selection, user plane network element redirection, Internet Protocol (IP) address allocation, bearer establishment, modification and release, and quality of service (QoS) control.

[0177] The PCF network element is mainly responsible for policy control decisions, providing policy rules for control plane functions, and flow-based charging control functions.

[0178] NRF network elements can support the registration and discovery of network functions.

[0179] The UPF network element is primarily responsible for forwarding and receiving user data from terminals. It can receive user data from the data network and transmit it to the terminal via access network equipment. It can also receive user data from the terminal via access network equipment and forward it to the data network. The transmission resources and scheduling functions provided by the UPF network element to the terminal are managed and controlled by the SMF network element.

[0180] The UDM network element is mainly responsible for UE subscription data management, including the storage and management of UE identification, UE access authorization, etc.

[0181] The AUSF network element mainly supports 3GPP and non-3GPP access authentication.

[0182] NEF network elements mainly support the secure interaction between 3GPP networks and third-party applications.

[0183] The AF network element mainly supports interaction with the 3GPP core network to provide services, such as influencing data routing decisions, policy control functions, or providing some third-party services to the network side.

[0184] The NSSF network element is mainly responsible for network slice selection and determines the network slice instance that the UE is allowed to access based on the UE's slice selection auxiliary information, contract information, etc.

[0185] DN may be a network used to provide transmission service data.

[0186] In addition, Figure 2 also shows the interaction between network functional entities and the corresponding interfaces. For example, the UE and AMF network elements can interact through the N1 interface, and the interaction messages are called N1 messages. Some interfaces are implemented as service-oriented interfaces.

[0187] It is understood that this communication system structure is only an example and does not limit the scope of this application. As an example, the communication system architecture may also include a network data analytics function (NWDAF) network element, which can support data collection from other network functions and AF network elements; support data collection from operation administration and maintenance (OAM); and support the provision of analysis information to other network functions and AF network elements.

[0188] In a communication system, a communication device can select a public land mobile network (PLMN) and access the selected PLMN through a subscriber identity module (SIM) to transmit services. In this application, a SIM card can also be referred to as a SIM card. An example of a SIM card is a universal subscriber identity module (USIM).

[0189] A PLMN selection method may include: upon determining that a SIM is present and available, the UE determines whether a previously registered PLMN (register PLMN, RPLMN) exists. If the RPLMN exists, registration is initiated with the RPLMN; if the RPLMN does not exist or registration fails, network selection is performed based on a network selection list. For example, the UE may select the highest-priority PLMN in the network selection list as the target PLMN for registration. If registration with the target PLMN is successful, services are transmitted based on the target PLMN. If registration with the target PLMN fails, the next highest-priority PLMN is determined as the new target PLMN for registration, and so on, until registration with the lowest-priority PLMN in the network selection list fails.

[0190] Specifically, the method for the UE to select a network according to the network selection list may be as shown in FIG3 .

[0191] S301: The non-access stratum (NAS) of the UE determines the PLMN with the highest priority in the network selection list as the target PLMN.

[0192] In this method, the network selection list may be pre-configured. As an example, when a SIM in a UE is registered, the core network device may configure a network selection list for the SIM and send the network selection list to the UE. After receiving the network selection list, the UE may store the network selection list.

[0193] Optionally, in some examples, two SIM cards may be inserted into the UE, and the core network device may configure a network selection list for each of the two SIM cards.

[0194] S302: The NAS layer sends a search request message to the access stratum (AS) of the UE, wherein the search request message is used to request a search for available cells of the UE in the target PLMN. Correspondingly, the AS layer receives the search request message.

[0195] In this application, the AS layer may also be referred to as a radio resource control (RRC) layer.

[0196] Optionally, the search request message may include the identity (ID) of the target PLMN.

[0197] S303: The AS layer triggers a cell search process.

[0198] S304: The AS layer receives a system message, where the system message includes the first PLMN.

[0199] In the method, the system message may be broadcast by the base station. The first PLMN may be the PLMN corresponding to the base station.

[0200] Optionally, the system message may include the ID of the first PLMN.

[0201] S305: The AS layer determines whether the first PLMN matches the target PLMN successfully. If so, S306 is executed; if not, S307 is executed.

[0202] In this method, if the first PLMN is the same as the target PLMN, the first PLMN is successfully matched with the target PLMN.

[0203] Optionally, whether the first PLMN and the target PLMN are the same may be determined by the ID of the first PLMN and the ID of the target PLMN. When the ID of the first PLMN and the ID of the target PLMN are the same, it is determined that the first PLMN and the target PLMN are the same.

[0204] S306: The AS layer sends a system message to the NAS layer.

[0205] S307: The AS layer sends an indication message to the NAS layer, where the indication message instructs the NAS layer to reselect a network.

[0206] S308: The NAS layer determines the PLMN with the second highest priority in the network selection list as the target PLMN, and then executes S302.

[0207] With the advancement of communication technology, a communication system has proposed a communication device that can include: at least two terminals and / or at least two SIM cards. For example, the communication device can include terminal 1 and terminal 2; or, the communication device can include SIM card 1 and SIM card 2; or, the communication device can include terminal 1, terminal 2, and terminal 3; or, the communication device can include SIM card 1, SIM card 2, and SIM card 3. These examples are merely illustrative and not limiting. Optionally, the communication device can include at least two protocol stacks: terminal 1 is replaced by protocol stack 1, and terminal 2 is replaced by protocol stack 2.

[0208] In this application, the communication device can be dual-directional. Taking the communication device including terminal 1 and terminal 2 as an example, dual-directional communication device can be understood as follows: the service data of the communication device can be directed to be transmitted through terminal 1 or terminal 2, or switched from being transmitted through terminal 1 to being transmitted through terminal 2. Alternatively, if terminal 1 and terminal 2 belong to the same user, the service data of the user can be directed to be transmitted through terminal 1 or terminal 2, or switched from being transmitted through terminal 1 to being transmitted through terminal 2.

[0209] However, no technical solution is provided for how the mobile communication device coordinates the two terminals or the two SIM cards, for example, how to coordinate the selection of a public land mobile network (PLMN) or how to coordinate service orientation. Next, this application will first illustrate the structure of the communication device with reference to Figures 4 to 6.

[0210] In one example, a communication device may be as shown in Figure 4. In this example, the communication device may include two UEs: UE1 and UE2. UE1 may be connected to RAN1, and UE2 may be connected to RAN2. UE1 and UE2 may each access a PLMN. The PLMN accessed by UE1 and the PLMN accessed by UE2 may be the same PLMN or different PLMNs.

[0211] In this example, each of the two UEs may include a SIM (not shown in FIG4 ). For example, UE1 may include SIM1, and UE2 may include SIM2.

[0212] The communication device may select a PLMN for each of the two UEs and access the PLMN. In other words, the communication device may select a PLMN for each SIM card of the two UEs and access the PLMN.

[0213] In the communication device, the PLMNs accessed by the two UEs may be collaboratively selected (or jointly selected). In other words, the PLMNs accessed by the SIM cards of the two UEs may be collaboratively selected.

[0214] In another example, a communication device may be as shown in Figure 5. In this example, the communication device may include two SIM cards: SIM1 and SIM2. The communication device may be connected to two RANs via the two SIM cards, and then the communication device may transmit service data via the two RANs.

[0215] In this example, the communication device can select and access PLMNs for the two SIMs respectively. In this communication device, the PLMNs accessed by the two SIMs can be selected collaboratively.

[0216] Subsequently, this application will take the communication device shown in FIG4 as an example to introduce the solution of this application.

[0217] In the present application, from a functional perspective, the structure of the communication device can be as shown in Figure 6. The communication device may include a dual-directional layer (DualSteer layer, DS layer), the NAS layer and AS layer of UE1, and the NAS layer and AS layer of UE 2. As an example, the mobile communication device may include a dual-directional layer, NAS layer 1, NAS layer 2, AS layer 1 and AS layer 2, wherein NAS layer 1 and NAS layer 2 are the NAS layers corresponding to UE1 and UE2 respectively, and AS layer 1 and AS layer 2 are the AS layers corresponding to UE1 and UE2 respectively. In the present application, the DS layer can also be called a dual-directional control layer (DualSteer control layer).

[0218] FIG7 is a flow chart of a control method for a communication device provided in an embodiment of the present application.

[0219] The method may be executed by the communication device shown in Figure 4 , or may be executed by a chip in the communication device shown in Figure 4 . The functional structure of the communication device may be as shown in Figure 6 .

[0220] S701: A communication device selects a first PLMN as a serving PLMN for a first UE.

[0221] In the method, the communication device may include a first UE and a second UE.

[0222] From a functional perspective, the communication device may include a dual-directional layer, a first NAS layer, a second NAS layer, a first AS layer, and a second AS layer. The first NAS layer and the second NAS layer are NAS layers for the first UE and the second UE, respectively, and the first AS layer and the second AS layer are AS layers for the first UE and the second UE, respectively.

[0223] As an example, the first UE may be UE1 in the communication device shown in Figure 4, and the second UE may be UE2 in the communication device shown in Figure 4. In this example, the first NAS layer may be the NAS layer of UE1, and the second NAS layer may be the NAS layer of UE2.

[0224] As another example, the first UE may be UE2 in the communication device shown in Figure 4, and the second SIM may be UE1 in the communication device shown in Figure 4. In this example, the first NAS layer may be the NAS layer of UE2, and the second NAS layer may be the NAS layer of UE1.

[0225] In this method, the serving PLMN of the first UE may be understood as: the PLMN accessed by the first UE.

[0226] In one possible implementation, a method for a communication device to select a first PLMN as a serving PLMN for a first UE may include: a first NAS layer selecting, based on a first network selection list, a PLMN as a searching PLMN (searching PLMN), for example, the searching PLMN being the PLMN with the highest priority in the first network selection list, and then sending a search request message to a first AS layer, the search request message being used to request a search for available cells of the first UE in the searching PLMN. After receiving the search request message, the first AS layer triggers a cell search process and receives a system message, the system message including the PLMN. If the PLMN in the system message matches the search PLMN successfully (or the PLMN in the system message and the search PLMN are the same PLMN), the first AS layer can send the system message to the first NAS layer, and the first NAS layer can determine that the search PLMN is the first PLMN and use the first PLMN as the service PLMN of the first UE; if the PLMN in the system message fails to match the search PLMN (or the PLMN in the system message and the search PLMN are different PLMNs), the first AS layer can send an indication message to the first NAS layer, and the indication message indicates that the match failed. After receiving the indication message, the first NAS layer can reselect a PLMN with the second highest priority as the search PLMN according to the first network selection list. And so on, until the PLMN in the system message and the search PLMN are the same PLMN, or there is no PLMN to be selected in the first network selection list.

[0227] The first network selection list may be a network selection list corresponding to the first UE. The first network selection list may include at least one PLMN and a priority of the at least one PLMN.

[0228] In this application, the search PLMN can be understood as the PLMN to be searched, and the terminal device can perform a cell search based on the search PLMN.

[0229] Assume that Figure 8 is a schematic diagram of a first network selection list provided in one embodiment of the present application. In this example, the first network selection list may include PLMN1, PLMN2, and PLMN3, where PLMN1 has a priority of 0 or 1st, PLMN2 has a priority of 1 or 2nd, and PLMN3 has a priority of 2 or 3rd. PLMN1 has a higher priority than PLMN2, and PLMN2 has a higher priority than PLMN3.

[0230] In this example, the first NAS layer can first select PLMN1 as the search PLMN. When PLMN1 successfully matches the PLMN in the system message received by the first AS layer, the first NAS layer can determine that PLMN1 is the first PLMN; when PLMN1 fails to match the PLMN in the system message received by the first AS layer, PLMN2 can be selected as the search PLMN. When PLMN2 successfully matches the PLMN in the system message received by the first AS layer, the first NAS layer can determine that PLMN2 is the first PLMN; when PLMN2 fails to match the PLMN in the system message received by the first AS layer, PLMN3 can be selected as the search PLMN. When PLMN3 successfully matches the PLMN in the system message received by the first AS layer, the first NAS layer can determine that PLMN3 is the first PLMN; when PLMN3 fails to match the PLMN in the system message received by the first AS layer, the waiting state can be entered.

[0231] Optionally, the first network selection list may further include an access technology corresponding to each PLMN in at least one PLMN. The access technology corresponding to each PLMN is used to determine the radio carrier type corresponding to each PLMN to search for each PLMN. The access technology of the PLMN may include a radio access technology (RAT) type, such as evolved universal terrestrial radio access (E-UTRA), 5G NR, 5G NR (satellite), or 6G.

[0232] Optionally, the first network selection list may be configured in advance for the communication device. After receiving the first network selection list, the communication device may store the first network selection list.

[0233] S702: The communication device selects a second PLMN as a serving PLMN for a second UE, where the first PLMN and the second PLMN are different PLMNs.

[0234] In this method, the serving PLMN of the second UE may be understood as the PLMN accessed by the second UE.

[0235] In a first possible implementation manner, the second PLMN may be selected by the second NAS layer.

[0236] In this implementation, the method for the communication device to select the second PLMN as the serving PLMN of the second SIM based on the second NAS layer may be as shown in FIG9 .

[0237] S901: The first NAS layer transmits first information to the DS layer, where the first information instructs the first NAS layer to select a first PLMN as a serving PLMN for a first UE, or the first information indicates that the first PLMN is a serving PLMN for the first UE. Accordingly, the DS layer receives the first information.

[0238] Optionally, when the communication device is in the dual-directional mode or the communication device is authorized for dual-directional operation, the DS layer requests the first NAS layer to obtain the serving PLMN of the first UE, and the first NAS layer transmits the first information to the DS layer.

[0239] S902: The DS layer sends the first PLMN to the second NAS layer.

[0240] In this method, the DS layer sends the first PLMN to the second NAS layer, which can indirectly instruct the second NAS layer to select a PLMN different from the first PLMN, or the DS layer sends the first PLMN and indication information of selecting a PLMN different from the first PLMN to the second NAS layer.

[0241] Optionally, when the communication device is in the dual-directional mode or the communication device is authorized for dual-directional operation, the DS layer sends the first PLMN to the second NAS layer.

[0242] S903: The second NAS layer selects a second PLMN as a serving PLMN for the second UE, where the second PLMN is different from the first PLMN.

[0243] As an example, the second NAS layer may select the second PLMN based on the second network selection list.

[0244] The second network selection list may be a network selection list corresponding to the second UE. The second network selection list may include at least one PLMN and a priority of the at least one PLMN.

[0245] Optionally, the second network selection list may be configured in advance for the communication device. After receiving the second network selection list, the communication device may store the second network selection list.

[0246] In this example, the second NAS layer may first select a PLMN different from the first PLMN as a search PLMN based on the second network selection list. For example, the search PLMN is the PLMN with the highest priority in the second network selection list and different from the first PLMN. The second NAS layer then sends a search request message to the second AS layer. The search request message is used to request a search for available cells for the second UE in the search PLMN. After receiving the search request message, the second AS layer triggers a cell search process and receives a system message, which includes the PLMN. If the PLMN in the system message matches the search PLMN successfully (or the PLMN in the system message and the search PLMN are the same PLMN), the second AS layer can send the system message to the second NAS layer, and the second NAS layer can determine that the search PLMN is the second PLMN and use the second PLMN as the service PLMN of the second UE; if the PLMN in the system message fails to match the search PLMN (or the PLMN in the system message and the search PLMN are different PLMNs), the second AS layer can send an indication message to the second NAS layer, which indicates that the match failed. After receiving the indication message, the second NAS layer can reselect a PLMN with the second highest priority and different from the first PLMN as the search PLMN according to the second network selection list. And so on, until the PLMN in the system message and the search PLMN are the same PLMN, or there is no PLMN to be selected in the second network selection list.

[0247] For example, assuming that the second network selection list may include PLMN4 and PLMN5, where PLMN4 has a higher priority than PLMN5. After receiving the first PLMN, the second NAS layer may first determine whether PLMN4 is the same as the first PLMN. If PLMN4 is different from the first PLMN, PLMN4 is determined as the search PLMN. The second AS layer then further determines whether the search PLMN cell search is successful. If PLMN4 is the same as the first PLMN, PLMN4 is skipped and PLMN5 is determined as the search PLMN.

[0248] Optionally, the second NAS layer may further select a second PLMN based on the first PLMN set, wherein the second PLMN may be a PLMN with the highest priority in the first PLMN set, and the PLMNs in the first PLMN set are different from the first PLMN.

[0249] Optionally, the first PLMN set may be a PLMN in the second network selection list that is different from the first PLMN, and the second network selection list may be a network selection list corresponding to the second UE. The second network selection list may include at least one PLMN and a priority of the at least one PLMN.

[0250] Optionally, the second network selection list may be configured in advance for the communication device. After receiving the second network selection list, the communication device may store the second network selection list.

[0251] In this example, the second NAS layer may first determine the first PLMN set based on the second network selection list, then select a PLMN with the highest priority from the first PLMN set as the search PLMN, and then send a search request message to the second AS layer. This search request message requests a search for available cells within the search PLMN for the second UE. After receiving the search request message, the second AS layer triggers a cell search process and receives a system message containing a PLMN. If the PLMN in the system message matches the search PLMN (or the PLMN in the system message and the search PLMN are the same), the second AS layer may send the system message to the second NAS layer. The second NAS layer may determine that the search PLMN is the second PLMN and use the second PLMN as the serving PLMN for the second UE. If the PLMN in the system message fails to match the search PLMN (or the PLMN in the system message and the search PLMN are different), the second AS layer may send an indication to the second NAS layer indicating the match failure. After receiving the indication message, the second NAS layer may reselect a PLMN with the next highest priority from the first PLMN set as the search PLMN. This process is deduced in this way until the PLMN in the system message is the same as the searched PLMN, or there is no PLMN to be selected in the first PLMN set.

[0252] For example, assuming that the second network selection list may include PLMN4, PLMN5, and PLMN6, where the priority of PLMN4 is higher than the priority of PLMN5, and the priority of PLMN5 is higher than the priority of PLMN6. Assuming that PLMN6 is the same PLMN as the first PLMN, the second NAS layer may determine that PLMN4 and PLMN5 are included in the first PLMN set.

[0253] Furthermore, the second NAS layer may first select PLMN4 as the search PLMN. When PLMN4 successfully matches the PLMN in the system message received by the second AS layer, the second NAS layer may determine that PLMN4 is the second PLMN. When PLMN4 fails to match the PLMN in the system message received by the second AS layer, PLMN5 may be selected as the search PLMN. When PLMN5 successfully matches the PLMN in the system message received by the second AS layer, the second NAS layer may determine that PLMN5 is the second PLMN. When PLMN5 fails to match the PLMN in the system message received by the second AS layer, the second NAS layer may enter a waiting state.

[0254] In this implementation, after receiving the first PLMN, the second NAS layer can select the second PLMN based on the first PLMN. This can reduce the number of interactions between the DS layer and the second NAS layer, which is conducive to improving the efficiency of selecting the second PLMN.

[0255] In a second possible implementation manner, the second PLMN may also be selected by the DS layer.

[0256] Optionally, the method for the communication device to select the second PLMN as the serving PLMN of the second UE based on the DS layer may be as shown in FIG10 .

[0257] S1001: A first NAS layer transmits first information to a DS layer, where the first information instructs the first NAS layer to select a first PLMN as a serving PLMN of the first PLMN. Correspondingly, the DS layer receives the first information.

[0258] Optionally, when the communication device is in the dual-directional mode or the communication device is authorized for dual-directional operation, the DS layer requests the first NAS layer to obtain the serving PLMN of the first UE, and the first NAS layer transmits the first information to the DS layer.

[0259] S1002: The second NAS layer transmits second information to the DS layer, where the second information indicates that the PLMN selected by the second NAS layer for the second UE is the second PLMN. Correspondingly, the DS layer receives the second information.

[0260] Optionally, when the communication device is in dual-directional mode or is authorized for dual-directional operation, the DS layer requests the second NAS layer to obtain the PLMN selected for the second UE or obtain the search PLMN, and the second NAS layer transmits the second information to the DS layer.

[0261] In this method, the PLMN selected by the second NAS layer for the second UE may be a search PLMN or a serving PLMN.

[0262] Optionally, when the PLMN selected by the second NAS layer for the second UE is a search PLMN, the second NAS layer can first select a PLMN as the search PLMN based on the second network selection list, for example, the search PLMN is the PLMN with the highest priority in the second network selection list, and then transmit the second information to the DS layer.

[0263] For example, assuming that the second network selection list may include PLMN4, PLMN5, and PLMN6, wherein the priority of PLMN4 is higher than the priority of PLMN5, and the priority of PLMN5 is higher than the priority of PLMN6, the second NAS layer may first select PLMN4 as the search PLMN.

[0264] Optionally, when the PLMN selected by the second NAS layer for the second UE is a serving PLMN, the second NAS layer can first select a PLMN as a serving PLMN based on the second network selection list, for example, the serving PLMN is the PLMN with the highest priority and successful cell search in the second network selection list, and then transmit the second information to the DS layer.

[0265] For example, assuming that the second network selection list may include PLMN4, PLMN5, and PLMN6, where the priority of PLMN4 is higher than the priority of PLMN5, and the priority of PLMN5 is higher than the priority of PLMN6. Assuming that the cell search for PLMN4 is successful, the second NAS layer may first select PLMN4 as the serving PLMN.

[0266] In this example, the PLMN cell search is successful can be understood as: the PLMN in the search request message received by the second AS layer from the second NAS layer is successfully matched with the PLMN in the received system message.

[0267] S1003: If the second PLMN is different from the first PLMN, the DS layer transmits third information to the second NAS layer, where the third information indicates that the second PLMN is approved as a serving PLMN for the second UE.

[0268] Optionally, the DS layer transmits the third information to the second NAS layer only when the communication device is in the bidirectional mode or the communication device is authorized for bidirectional operation.

[0269] Optionally, assuming that the second PLMN is a search PLMN, after receiving the third information, the second NAS layer needs to further determine whether the cell search for the second PLMN can be successful. For example, the second NAS layer sends a search request message to the second AS layer, where the search request message is used to request that the second UE search for available cells in the search PLMN.

[0270] If the second PLMN cell search is successful, the second NAS layer may also send an indication message of the second PLMN cell search success to the DS layer. The DS layer may determine the second PLMN as the serving PLMN for the second SIM only after receiving the indication message.

[0271] In the case that the second PLMN cell search fails, the second NAS layer may further send an indication message of the second PLMN cell search failure to the DS layer. After receiving the indication message, the DS layer may instruct the second NAS layer to reselect a PLMN.

[0272] In this method, the DS layer determines whether the PLMN selected by the second NAS layer is the same as the first PLMN. In this way, the second NAS layer does not need to perform this determination process, which not only avoids direct interaction between the first and second NAS layers, but also helps improve the efficiency of the second NAS in selecting the second PLMN.

[0273] Optionally, the method for the communication device to select the second PLMN as the serving PLMN of the second UE based on the DS layer may also be as shown in FIG11 .

[0274] S1101: A first NAS layer transmits first information to a DS layer, where the first information instructs the first NAS layer to select a first PLMN as a serving PLMN for a first UE. Correspondingly, the DS layer receives the first information.

[0275] Optionally, when the communication device is in the dual-directional mode or the communication device is authorized for dual-directional operation, the DS layer requests the first NAS layer to obtain the serving PLMN of the first UE, and the first NAS layer transmits the first information to the DS layer.

[0276] S1102: The second NAS layer transmits second information to the DS layer, where the second information indicates that the PLMN selected by the second NAS layer for the second UE is a third PLMN. Correspondingly, the DS layer receives the second information.

[0277] Optionally, when the communication device is in dual-directional mode or is authorized for dual-directional operation, the DS layer requests the second NAS layer to obtain the PLMN selected for the second UE or obtain the search PLMN, and the second NAS layer transmits the second information to the DS layer.

[0278] In this method, the PLMN selected by the second NAS layer for the second UE may be a search PLMN or a serving PLMN.

[0279] The method for the second NAS layer to select a PLMN for the second UE may refer to the aforementioned S1002 and will not be repeated here.

[0280] S1103: If the third PLMN is the same as the first PLMN, the DS layer transmits fourth information to the second NAS layer, indicating that the third PLMN is not approved as the serving PLMN for the second UE or instructing the second NAS layer to reselect a PLMN. In response, the second NAS layer receives the fourth information.

[0281] Optionally, the DS layer transmits the fourth information to the second NAS layer only when the communication device is in the bidirectional mode or the communication device is authorized for bidirectional operation.

[0282] S1104: The second NAS layer selects a second PLMN as a serving PLMN for the second UE according to the fourth information.

[0283] In this method, the second NAS layer may select the PLMN with the highest priority and successful cell search from among the other PLMNs based on the second network selection list. The other PLMN may be any PLMN other than the third PLMN in the second network selection list.

[0284] Optionally, the second NAS layer further retransmits second information to the DS layer, where the second information indicates the PLMN reselected by the second NAS layer for the second UE.

[0285] In this method, the DS layer determines whether the PLMN selected by the second NAS layer is the same as the first PLMN. In this way, the second NAS layer does not need to perform this determination process, which not only avoids direct interaction between the first and second NAS layers, but also helps improve the efficiency of the second NAS in selecting the second PLMN.

[0286] In the present application, the first PLMN and the second PLMN selected by the communication device are different. When the network connected to one UE in the communication device is disconnected, the other UE can still be connected to the network, avoiding the situation where both UEs in the communication device are disconnected from the network due to a network failure or connection interruption, which is beneficial to improving the reliability of the communication device's access to the network.

[0287] Furthermore, the first PLMN and the second PLMN may also be PLMNs supporting dual-directionality. In other words, the PLMN accessed by the first UE and the PLMN accessed by the second UE may also be PLMNs supporting dual-directionality.

[0288] In the present application, the PLMN supporting dual-directionality can be understood as: the PLMN supports that the service of the communication device can be switched between different UEs (the first UE and the second UE included in the communication device).

[0289] When both the first PLMN and the second PLMN selected by the communication device support dual-direction, the communication device can implement the dual-direction feature, for example, the communication device can control service direction and service switching processes to complete the transmission of service data.

[0290] In a possible implementation, the DS layer of the communication device may send fifth information to the first NAS layer and the second NAS layer respectively, where the fifth information requests selection of a PLMN supporting dual-directionality, and then the first NAS layer and the second NAS layer respectively select a PLMN according to the fifth information.

[0291] Furthermore, the first NAS layer and the second NAS layer may send the selected PLMN to the DS layer. Alternatively, the first NAS layer and the second NAS layer may send information on whether a PLMN supporting dual-directional is found to the DS layer.

[0292] In this implementation, the PLMN selected by the first NAS layer according to the fifth information may be the PLMN with the highest priority in the first network selection list, the PLMN for which the cell search is successful and which supports dual-directionality.

[0293] For example, the first NAS layer may first select the PLMN with the highest priority and a successful cell search based on the first network selection list and access the PLMN. The first NAS layer may then obtain information indicating whether the PLMN supports dual-directional support. If the information indicates that the PLMN supports dual-directional support, the PLMN may be determined as the first PLMN and sent to the DS layer. If the information indicates that the PLMN does not support dual-directional support, the PLMN with the next highest priority may be selected for cell search.

[0294] For another example, the first NAS layer may first receive indication information indicating whether each PLMN in the first network selection list supports dual-directional positioning. It may then select the PLMN with the highest priority that supports dual-directional positioning based on the first network selection list and determine whether a cell search for that PLMN is successful. If the cell search for that PLMN is successful, the PLMN may be determined as the first PLMN and sent to the DS layer. If the cell search for that PLMN fails, the next highest priority PLMN that supports dual-directional positioning may be selected for cell search based on the first network selection list.

[0295] The PLMN selected by the first NAS layer according to the fifth information is the PLMN with the highest priority in the first network selection list, the cell search is successful and supports dual-directionality, so that the communication device can implement the dual-directional feature through the first UE to complete the transmission of service data through the first UE.

[0296] Optionally, after receiving the first PLMN, the DS layer may send the fifth information to the second NAS layer.

[0297] Optionally, the fifth information may further include the first PLMN. In this way, the second NAS layer may select a PLMN that is different from the first PLMN, has the highest priority, has a successful cell search, and supports dual-directional directionality based on the fifth information.

[0298] For example, after receiving the fifth information, the second NAS layer may first select the PLMN with the highest priority, different from the first PLMN, and for which the cell search was successful, based on the second network selection list, and access the PLMN. The second NAS layer may then obtain indication information indicating whether the PLMN supports dual-directional. If the indication information indicates that the PLMN supports dual-directional, the PLMN may be determined as the second PLMN and sent to the DS layer. If the indication information indicates that the PLMN does not support dual-directional, a PLMN with the next highest priority and different from the first PLMN may be selected for cell search.

[0299] For another example, the second NAS layer may first receive indication information indicating whether each PLMN in the second network selection list supports dual-directional positioning. Then, after receiving the fifth information, the second NAS layer may select a PLMN with the highest priority, supports dual-directional positioning, and is different from the first PLMN based on the first network selection list, and determine whether a cell search for that PLMN is successful. If the cell search for that PLMN is successful, the second PLMN may be determined as the second PLMN and sent to the DS layer. If the cell search for that PLMN fails, the second PLMN with the second highest priority, supports dual-directional positioning, and is different from the first PLMN may be selected for cell search based on the second network selection list.

[0300] Based on the fifth information, the second NAS layer selects a PLMN that is different from the first PLMN, has the highest priority, has successfully searched for a cell, and supports dual-directional communication. This allows the communication device to implement dual-directional communication through the second UE, thereby completing service data transmission through the second UE. Furthermore, the second PLMN is different from the first PLMN, thereby preventing both UEs in the communication device from being disconnected from the network due to a network failure or connection interruption.

[0301] In another possible implementation, the DS layer of the communication device may first determine the first PLMN and the second PLMN, and then obtain whether the first PLMN and the second PLMN support dual-directionality.

[0302] In this implementation, the first PLMN may be the PLMN with the highest priority in the first network selection list and whose cell search is successful. The second PLMN may be the PLMN with the highest priority in the second network selection list and whose cell search is successful and which is different from the first PLMN.

[0303] In this implementation, the first PLMN and the second PLMN may be determined based on the method shown in FIG. 7 .

[0304] Optionally, the DS layer receives sixth information transmitted by the first NAS layer, where the sixth information indicates whether the first PLMN supports dual-direction, and the first NAS layer is the NAS layer of the first UE; if the sixth information indicates that the first PLMN supports dual-direction, the DS layer determines to use the first PLMN as the service PLMN for the first UE; if the sixth information indicates that the first PLMN does not support dual-direction, the DS layer sends seventh information to the first NAS layer, where the seventh information indicates that it does not agree to use the first PLMN as the service PLMN for the first UE or instructs the first NAS layer to select a PLMN that supports dual-direction, and then the first NAS layer reselects the PLMN based on the seventh information.

[0305] In this method, when a first UE registers, the first NAS layer may obtain from the core network whether the first UE's serving PLMN supports dual-directionality, and then send sixth information to the DS layer, the sixth information indicating whether the first UE's serving PLMN supports dual-directionality. The first UE's serving PLMN may be a first PLMN selected by the first UE.

[0306] Optionally, the method for the first NAS layer to reselect a PLMN based on the seventh information may include: the first NAS layer may first select, based on the first network selection list, a PLMN that is different from the first PLMN, has the highest priority, and supports dual-directional positioning as a search PLMN, and then send a search request message to the first AS layer, the search request message being used to request a search for available cells of the first UE in the search PLMN. After receiving the search request message, the first AS layer triggers a cell search process and receives a system message containing a PLMN. If the PLMN in the system message successfully matches the search PLMN (or the PLMN in the system message and the search PLMN are the same PLMN), the first AS layer may send the system message to the first NAS layer, and the first NAS layer may determine that the search PLMN is the serving PLMN for the first UE. If the PLMN in the system message fails to match the search PLMN (or the PLMN in the system message and the search PLMN are different PLMNs), the first AS layer may send an indication message to the first NAS layer indicating the match failure. After receiving the indication message, the first NAS layer may reselect, based on the first network selection list, a PLMN that is different from the first PLMN, has the next highest priority, and supports dual-directional positioning as the search PLMN. This process is repeated in this way until the PLMN in the system message is the same as the searched PLMN, or there is no PLMN available for selection in the first network selection list.

[0307] Optionally, the DS layer receives sixth information transmitted by the second NAS layer, where the sixth information indicates whether the second PLMN supports dual-direction, and the second NAS layer is the NAS layer of the second UE; if the sixth information indicates that the second PLMN supports dual-direction, the DS layer determines to use the second PLMN as the service PLMN for the second UE; if the sixth information indicates that the second PLMN does not support dual-direction, the DS layer sends seventh information to the second NAS layer, where the seventh information indicates that it does not agree to use the second PLMN as the service PLMN for the second UE or instructs the second NAS layer to select a PLMN that supports dual-direction, and then the second NAS layer reselects the PLMN based on the seventh information.

[0308] In this method, when the second SIM registers, the second NAS layer may obtain from the core network whether the second SIM's serving PLMN supports dual-directional positioning, and then send sixth information to the DS layer, indicating whether the second SIM's serving PLMN supports dual-directional positioning. The second SIM's serving PLMN may be a second PLMN selected by the second SIM.

[0309] In this implementation, the DS can determine whether the second PLMN supports dual-directionality based on the sixth information, which is conducive to obtaining a PLMN that supports dual-directionality and is different from the first PLMN, and thus is conducive to the communication device to realize the dual-directional feature, and can avoid the situation where both UEs in the communication device are disconnected from the network due to a network failure or connection interruption.

[0310] Optionally, the seventh information may also include the first PLMN.

[0311] Accordingly, the method for the second NAS layer to reselect a PLMN based on the seventh information may include: the second NAS layer may first select, based on the second network selection list, a PLMN that is different from the first PLMN and the second PLMN, has the highest priority, and supports dual-directional orientation as a search PLMN, and then send a search request message to the second AS layer, where the search request message is used to request a search for available cells for the second UE in the search PLMN. After receiving the search request message, the second AS layer triggers a cell search process and receives a system message, where the system message includes the PLMN. If the PLMN in the system message matches the search PLMN successfully (or the PLMN in the system message and the search PLMN are the same PLMN), the second AS layer can send the system message to the second NAS layer, and the second NAS layer can determine that the search PLMN is the service PLMN of the second UE; if the PLMN in the system message fails to match the search PLMN (or the PLMN in the system message and the search PLMN are different PLMNs), the second AS layer can send an indication message to the second NAS layer, and the indication message indicates that the match failed. After receiving the indication message, the second NAS layer can reselect a PLMN that is different from the first PLMN and the second PLMN, has the second highest priority and supports dual-directional as the search PLMN according to the second network selection list. And so on, until the PLMN in the system message and the search PLMN are the same PLMN, or there is no PLMN to be selected in the second network selection list.

[0312] In this method, the second NAS layer can reselect a PLMN that supports dual-directionality and is different from the first PLMN based on the seventh information, which is conducive to the communication device to realize the dual-directional feature, and can avoid the situation where both UEs in the communication device are disconnected from the network due to a network failure or connection interruption.

[0313] In the present application, the communication device can control service orientation, and the communication device controlling service orientation can be understood as: when the communication device is triggered by a target service, a specific UE can be selected to transmit the target service.

[0314] Optionally, the method for a communication device to control service orientation may be as shown in FIG12 .

[0315] S1201, the communication device determines a first target UE, where the first target UE is one of a first UE and a second UE.

[0316] In the method, the communication device may include a first UE and a second UE.

[0317] From a functional perspective, the communication device may include a dual-directional layer, a first NAS layer, a second NAS layer, a first AS layer, and a second AS layer. The first NAS layer and the second NAS layer are NAS layers corresponding to the first UE and the second UE, respectively, and the first AS layer and the second AS layer are AS layers corresponding to the first UE and the second UE, respectively.

[0318] As an example, the first UE may be UE1 in the communication device shown in Figure 4, and the second SIM may be UE2 in the communication device shown in Figure 4. In this example, the first NAS layer may be the NAS layer of UE1, and the second NAS layer may be the NAS layer of UE2.

[0319] As another example, the first UE may be UE2 in the communication device shown in Figure 4, and the second SIM may be UE1 in the communication device shown in Figure 4. In this example, the first NAS layer may be the NAS layer of UE2, and the second NAS layer may be the NAS layer of UE1.

[0320] In one possible implementation, a method for a communication device to determine a first target UE may include: obtaining a service orientation policy, the service orientation policy including at least one service and a PLMN and / or RAT preferentially associated with each service in at least one service, and at least one service including a target service; obtaining first access information and second access information, the first access information including the PLMN and / or RAT accessed by the first UE, and the second access information including the PLMN and / or RAT accessed by the second UE; determining the first target UE based on the first access information, the second access information, and the service orientation policy, the PLMN accessed by the first target UE being the PLMN preferentially associated with the target service, and / or the RAT accessed by the first target UE being the RAT preferentially associated with the target service.

[0321] Optionally, the service targeting policy includes the PLMN and / or RAT with which services of the communication device are preferentially associated. It should be understood that the PLMN and / or RAT with which each service of the communication device is preferentially associated are the same. In this case, the target service can be any service of the communication device.

[0322] In this implementation, the communication device may obtain the service orientation policy through the first UE or the second UE. As an example, when the first UE or the second UE registers, the service orientation policy may be obtained from the network.

[0323] As an example, assuming that the service orientation policy includes that the target service is preferentially transmitted through the first PLMN, and the first UE accesses the first PLMN and the second UE accesses the second PLMN, the communication device may determine the first UE as the first target UE.

[0324] In this implementation, the communication device may transmit the target service according to the PLMN preferentially associated with the target service to meet the requirements of the target service.

[0325] Optionally, the communication device further obtains the connection status of the first UE and the connection status of the second UE, and determines the first target UE based on the first access information, the second access information, the service orientation policy, the connection status of the first UE, and the connection status of the second UE. The connection status of the first UE may include any one or more of the following: an air interface signal value of the first UE, or a measurement value between the first UE and a UPF network element. The connection status of the second UE may include any one or more of the following: an air interface signal value of the second UE, or a measurement value between the second UE and a UPF network element.

[0326] As an example, assuming that the service targeting policy includes that the target service is preferentially transmitted through the first PLMN, and the first UE accesses the first PLMN and the second UE accesses the second PLMN, but the connection status of the first UE is not good or is lower than a preset threshold, the communication device can determine the second UE as the first target UE.

[0327] In another possible implementation, the communication device may also determine the first target UE through the DS layer.

[0328] The method for a communication device to determine a first target UE through a DS layer may include: the DS layer obtains a service orientation policy from a first NAS layer or a second NAS layer, the service orientation policy including at least one service and a PLMN and / or RAT preferentially associated with each service in at least one service, at least one service including a target service, the first NAS layer is the NAS layer of the first UE, and the second NAS layer is the NAS layer of the second UE; the DS layer obtains first access information from the first NAS layer or the first AS layer, the first access information including the PLMN and / or RAT accessed by the first UE, and the first AS layer is the AS layer of the first UE; the DS layer obtains second access information from the second NAS layer or the second AS layer, the second access information including the PLMN and / or RAT accessed by the second UE, and the second AS layer is the AS layer of the second UE; the DS layer determines the first target UE based on the first access information, the second access information, and the service orientation policy, the PLMN accessed by the first target UE is the PLMN preferentially associated with the target service, and / or the RAT accessed by the first target UE is the RAT preferentially associated with the target service.

[0329] In this implementation, the DS layer may obtain the service orientation policy through the first NAS layer or the second NAS layer.

[0330] As an example, when the first UE registers, the first UE or the first NAS layer can receive or obtain the service orientation policy through the network, and then the first NAS layer sends the service orientation policy to the DS layer. After receiving the service orientation policy, the DS layer stores the service orientation policy.

[0331] As another example, when the second UE registers, the second UE or the second NAS layer can receive or obtain the service orientation policy through the network, and then the second NAS layer sends the service orientation policy to the DS layer, and the DS layer stores the service orientation policy after receiving the service orientation policy.

[0332] As an example, assuming that the service orientation policy includes that the target service is preferentially transmitted through the first PLMN, and the first UE accesses the first PLMN and the second UE accesses the second PLMN, the DS layer of the communication device can determine the first UE as the first target UE.

[0333] In this implementation, the DS layer of the communication device may transmit the target service according to the PLMN to which the target service is preferentially associated, so as to meet the requirements of the target service.

[0334] S1202: The communication device transmits a target service based on the first target UE.

[0335] In the method, the communication device can establish a session and transmit the target service through a route selection policy (URSP) of the first target UE.

[0336] Optionally, when the communication device determines that both the first PLMN and the second PLMN support dual-direction, or when the DS layer of the communication device determines that both the first PLMN and the second PLMN support dual-direction, the communication device determines the first target UE when a target service is triggered.

[0337] In this application, the communication device can coordinate how the communication device's services are directed to the two UEs through the DS layer, thereby avoiding direct interaction between the NAS layers of the two UEs and avoiding additional impact on the NAS of the two UEs.

[0338] In the present application, the communication device may also control service switching, and the communication device controlling service switching may be understood as: the communication device transfers the service transmitted through one UE to the service transmitted through another UE.

[0339] In one possible implementation, a method for a communication device to control service switching may include: determining to transmit the target service through a second target UE based on the connection status of a first target UE, where the second target UE is a UE other than the first target UE between the first UE and the second UE.

[0340] In this implementation, the first target UE may be a UE used by the communication device to transmit the target service.

[0341] As an example, the first target UE may be a first UE, and correspondingly, the second target UE may be a second UE.

[0342] As another example, the first target UE may be the second UE. Correspondingly, the second target UE may be the first UE.

[0343] Optionally, the first target UE may be a UE selected for the target service when the communication device controls service direction.

[0344] In this implementation, the communication device may determine the connection status of the first target UE based on the first target UE. The connection status of the first target UE may include any one or more of the following: an air interface signal value of the first target UE, or a measurement value between the first target UE and a UPF network element.

[0345] When the communication device transmits the target service based on the first target UE, the air interface signal value of the first target UE is lower than the preset threshold, and / or the measurement value between the first target UE and the UPF network element is lower than the preset threshold, the communication device can determine to transmit the target service through the second target UE.

[0346] Optionally, when the air interface signal value of the second target UE is higher than a preset threshold, the communication device may also determine to transmit the target service through the second target UE.

[0347] In this implementation, after the communication device determines to transmit the target service through the second target UE, it can establish a session or perform session switching based on the second target UE.

[0348] In this implementation method, the air interface signal value of the UE selected by the communication device for transmitting the target service meets the preset threshold requirement, or the measurement value between the UE selected by the communication device for transmitting the target service and the UPF network element meets the preset threshold, which is conducive to ensuring the transmission quality of the service data.

[0349] In another possible implementation, the method for a communication device to control service switching may include: the DS layer of the communication device obtains the connection status of the first target UE from the NAS layer of the first target UE or the AS layer of the first target UE; the DS layer determines to transmit the target service based on the second target UE according to the connection status of the first target UE, and the second target UE is a terminal other than the first target UE between the first UE and the second UE.

[0350] In this implementation, the first target UE may be a UE used by the communication device to transmit the target service.

[0351] As an example, the first target UE may be the first UE, the NAS layer of the first target UE may be the first NAS layer, and the AS layer of the first target UE may be the first AS layer. Correspondingly, the second target UE may be the second UE.

[0352] As another example, the first target UE may be the second UE, the NAS layer of the first target UE may be the second NAS layer, the AS layer of the first target UE may be the second AS layer. Accordingly, the second target UE may be the first UE.

[0353] Optionally, the first target UE may be a UE selected for the target service when the communication device controls service direction.

[0354] In this implementation, the connection status of the first target UE may include any one or more of the following: the air interface signal value of the first target UE, or the measurement value between the first target UE and the UPF network element.

[0355] When the communication device transmits the target service based on the first target UE, the air interface signal value of the first target UE is lower than the preset threshold, and / or the measurement value between the first target UE and the UPF network element is lower than the preset threshold, the DS layer of the communication device can determine to transmit the target service through the second target UE.

[0356] Optionally, when the air interface signal value of the second target UE is higher than a preset threshold, the DS layer of the communication device may also determine to transmit the target service through the second target UE.

[0357] In this implementation, after the DS layer of the communication device determines to transmit the target service through the second target UE, it can establish a session or perform session switching based on the second target UE.

[0358] In this implementation method, the air interface signal value of the UE selected by the DS layer of the communication device for transmitting the target service meets the preset threshold requirement, or the measurement value between the UE and the UPF network element selected by the DS layer of the communication device for transmitting the target service meets the preset threshold, which is conducive to ensuring the transmission quality of the service data.

[0359] In the technical solution of the present application, the communication device is in a dual-directional mode or the communication device is authorized for dual-directional operation.

[0360] Alternatively, the communication device may determine whether to be in the bi-directional mode based on a user instruction.

[0361] Assume that Figure 13 is a schematic diagram of a first user interface of a communication device provided in one embodiment of the present application. The first user interface includes a button for enabling dual-directional mode. When a user clicks the button for enabling dual-directional mode in the first user interface, the communication device may receive a first user instruction instructing the user to click on the dual-directional mode, and then determine that the communication device is in the dual-directional mode based on the first user instruction.

[0362] Optionally, the communication device may determine whether the dual-directional operation is authorized by receiving authorization information, and the authorization information may indicate that the dual-directional operation is authorized.

[0363] As an example, during the registration process of the first UE in the communication device, the first NAS layer may receive authorization information from the network and send the authorization information to the DS layer. After receiving the authorization information, the DS layer determines that the communication device is authorized for bidirectional operation.

[0364] As another example, during the registration process of the second UE in the communication device, the second NAS layer may receive authorization information from the network and send the authorization information to the DS layer. After receiving the authorization information, the DS layer determines that the communication device is authorized for bidirectional operation.

[0365] Only when the communication device is in dual-directional mode or the communication device is authorized for dual-directional operation can the communication device select different PLMNs and / or select a PLMN that supports dual-directional operation for the first UE and the second UE, thereby realizing the dual-directional feature of the communication device and avoiding the situation where both UEs in the communication device are disconnected from the network due to a network failure or connection interruption.

[0366] In the present application, the first UE may be a primary UE in the communication device, and / or the second UE may be a secondary UE in the communication device. In other words, the priority of the first UE is higher than that of the second UE.

[0367] Optionally, the priorities of the first UE and the second UE may also be configured in advance. As an example, a user may set the priorities of the first UE and the second UE in a communication device.

[0368] Assume that Figure 14 is a schematic diagram of a second user interface of a communication device provided in one embodiment of the present application. The second user interface includes a first button and a second button, wherein the first button is used to set a first UE as a primary terminal, and the second button is used to set a second UE as a primary terminal. When a user clicks the first button in the first user interface, the communication device can determine that the first UE is the primary terminal.

[0369] Optionally, the user may also directly input the primary terminal and / or the secondary terminal in the communication device.

[0370] In this method, since the priority of the first UE is higher than that of the second UE, the communication device may first determine the serving PLMN of the higher priority UE, and then determine the serving PLMN of the lower priority UE based on the serving PLMN of the higher priority UE.

[0371] In this method, since the service data processed by the primary terminal is usually more critical than the service data processed by the secondary terminal, first determining the network of the primary terminal is conducive to improving the transmission efficiency of the more critical service data.

[0372] FIG15 is a flow chart of a control method for a communication device provided in another embodiment of the present application.

[0373] The method may be executed by the communication device shown in Figure 4 , or may be executed by a chip in the communication device shown in Figure 4 . The functional structure of the communication device may be as shown in Figure 6 .

[0374] S1501: A communication device selects a first PLMN as a serving PLMN for a first UE, where the first PLMN is a PLMN supporting dual-directional directionality.

[0375] In the method, the communication device may include a first UE and a second UE.

[0376] From a functional perspective, the communication device may include a dual-directional layer, a first NAS layer, a second NAS layer, a first AS layer, and a second AS layer. The first NAS layer and the second NAS layer are NAS layers for the first UE and the second UE, respectively, and the first AS layer and the second AS layer are AS layers for the first UE and the second UE, respectively.

[0377] As an example, the first UE may be UE1 in the communication device shown in Figure 4, and the second SIM may be UE2 in the communication device shown in Figure 4. In this example, the first NAS layer may be the NAS layer of UE1, and the second NAS layer may be the NAS layer of UE2.

[0378] As another example, the first UE may be UE2 in the communication device shown in Figure 4, and the second SIM may be UE1 in the communication device shown in Figure 4. In this example, the first NAS layer may be the NAS layer of UE2, and the second NAS layer may be the NAS layer of UE1.

[0379] In this method, the serving PLMN of the first UE may be understood as the PLMN to which the first UE has accessed.

[0380] In this method, the PLMN supporting dual-directionality can be understood as: the PLMN supports services of the communication device that can be switched between different UEs (a first UE and a second UE included in the communication device).

[0381] Optionally, the communication device may receive information that the first PLMN supports dual-directional orientation through the first UE. For example, when the first UE registers, the NAS layer of the first UE may receive information from the network that the first PLMN supports dual-directional orientation. The information that the first PLMN supports dual-directional orientation may be carried in a NAS message. For example, the NAS message is a registration accept message, and the first UE receives the NAS message from the AMF.

[0382] In addition, the communication device may receive information indicating that the second PLMN supports dual-directional orientation through the second UE. For example, when the second UE registers, the NAS layer of the second UE may receive information indicating that the second PLMN supports dual-directional orientation from the network. The information indicating that the second PLMN supports dual-directional orientation may be carried in a NAS message. For example, the NAS message is a registration accept message, and the first UE receives the NAS message from the AMF.

[0383] In this implementation, the communication device can select the first PLMN as the PLMN of the first UE based on the information that the first PLMN supports dual-direction, and select the second PLMN as the PLMN of the second UE based on the information that the second PLMN supports dual-direction. In this way, the service PLMNs selected by the communication device for the first UE and the second UE both support dual-direction, thereby enabling the communication device to implement dual-direction characteristics. For example, the communication device can control service direction and service switching processes to complete the transmission of service data.

[0384] In a first possible implementation manner, the DS layer of the communication device determines to select a PLMN supporting dual-directionality for the first UE, and the first NAS layer selects the first PLMN as the serving PLMN of the first UE.

[0385] Optionally, a method for the communication device to select the first PLMN as the serving PLMN for the first UE is shown in FIG16 .

[0386] S1601: The DS layer sends a first request message to the first NAS layer, wherein the first request message requests selection of a PLMN supporting dual-directional communication. Correspondingly, the first NAS layer receives the first request message.

[0387] Optionally, when the communication device is in the dual-directional mode or the communication device is authorized for dual-directional operation, the DS layer of the communication device determines to select a PLMN supporting dual-directional for the first UE.

[0388] Optionally, after the DS layer of the communication device determines to select a PLMN supporting dual-directionality for the first UE, it sends first request information to the first NAS layer.

[0389] S1602: The first NAS layer selects a first PLMN as a serving PLMN for the first UE according to the first request information.

[0390] In this implementation, after receiving the first request information, the first NAS layer may select a first PLMN according to the first network selection list. The first PLMN is the PLMN with the highest priority in the first network selection list, has a successful cell search, and supports dual-directionality.

[0391] The first network selection list may be a network selection list corresponding to the first UE. The first network selection list may include at least one PLMN and a priority of the at least one PLMN.

[0392] For example, assume the first network selection list includes PLMN1, PLMN2, and PLMN3, where PLMN1 has a higher priority than PLMN2, and PLMN2 has a higher priority than PLMN3. If the cell search for PLMN1 is successful and supports dual-directional positioning, the first NAS layer can determine PLMN1 as the first PLMN. If the cell search for PLMN1 fails or does not support dual-directional positioning, the first NAS layer determines whether the cell search for PLMN2 is successful and whether PLMN2 supports dual-directional positioning. This process continues in this manner until a PLMN in the first network selection list is found that supports dual-directional positioning or there are no more PLMNs available for selection in the first network selection list.

[0393] In this example, the first NAS layer may obtain information from the network about whether PLMN1, PLMN2, and PLMN3 support bidirectional directionality.

[0394] Optionally, the first NAS layer may first determine one or more PLMNs supporting dual-directionality from the first network selection list, and then determine the PLMN with the highest priority among the one or more PLMNs as the first PLMN.

[0395] For example, assuming that the first network selection list may include PLMN1, PLMN2, and PLMN3, where the priority of PLMN1 is higher than the priority of PLMN2, and the priority of PLMN2 is higher than the priority of PLMN3. Assuming that the first NAS layer obtains information from the network that PLMN2 and PLMN3 support bidirectional positioning, the first NAS layer may determine PLMN2 as the first PLMN based on the priorities of PLMN2 and PLMN3.

[0396] In this implementation, the DS layer of the communication device can determine the PLMN with the highest priority in the first network selection list, the successful cell search and support for dual-directionality as the service PLMN of the first UE, so that the communication device can implement the dual-directional feature through the first UE to complete the transmission of service data through the first UE.

[0397] In addition, after receiving the first request message, the first NAS layer can select the first PLMN according to the first request message. This can reduce the number of interactions between the DS layer and the first NAS layer, which is conducive to improving the efficiency of selecting the first PLMN.

[0398] In a second possible implementation manner, the method for the communication device to select the first PLMN as the serving PLMN of the first UE may also be as shown in FIG. 17 .

[0399] S1701: The first NAS layer transmits first network information to the DS layer, where the first network information indicates that the PLMN selected by the first NAS layer for the first UE is the first PLMN. Correspondingly, the DS layer receives the first network information.

[0400] Optionally, the first network information may further include indication information of whether the first PLMN supports dual-directional communication.

[0401] Optionally, when the communication device is in dual-directional mode or the communication device is authorized for dual-directional operation, the DS layer requests the first NAS layer to obtain the PLMN selected for the first UE or obtain the search PLMN, and the first NAS layer then transmits the first network information to the DS layer.

[0402] In this implementation, the PLMN selected by the first NAS layer for the first UE may be a search PLMN or a serving PLMN.

[0403] Optionally, when the PLMN selected by the first NAS layer for the first UE is a search PLMN, the first NAS layer may select a PLMN with the highest priority as the first PLMN based on the first network selection list.

[0404] For example, assuming that the first network selection list may include PLMN1, PLMN2, and PLMN3, where the priority of PLMN1 is higher than the priority of PLMN2, and the priority of PLMN2 is higher than the priority of PLMN3, the first NAS layer may first select PLMN1 as the first PLMN and transmit first network information to the DS layer, where the first network information indicates that the PLMN selected by the first NAS layer for the first UE is PLMN1.

[0405] Optionally, when the PLMN selected by the first NAS layer for the first UE is a serving PLMN, the first NAS layer may select a PLMN with the highest priority and successful cell search as the first PLMN based on the first network selection list.

[0406] For example, assume that the first network selection list may include PLMN1, PLMN2, and PLMN3, where the priority of PLMN1 is higher than the priority of PLMN2, and the priority of PLMN2 is higher than the priority of PLMN3. If the PLMN1 cell search is successful, the first NAS layer may select PLMN1 as the first PLMN and transmit first network information to the DS layer. The first network information indicates that the first NAS layer has selected PLMN1 for the first UE.

[0407] S1702: If the first PLMN supports the dual-directional function, the DS layer sends first indication information to the first NAS layer, where the first indication information indicates that the first PLMN is accepted as the serving PLMN for the first UE. Accordingly, the first NAS layer receives the first indication information.

[0408] Optionally, the DS layer sends the first indication information to the first NAS layer only when the communication device is in the dual-directional mode or the communication device is authorized for dual-directional operation.

[0409] Optionally, when the PLMN selected by the first NAS layer for the first UE is a search PLMN, if the search PLMN supports dual-directionality, the DS layer may determine the search PLMN as the first PLMN and send a first indication message to the first NAS layer. After receiving the first indication message, the first NAS layer may perform a cell search based on the first PLMN and send an indication message to the DS layer as to whether the first PLMN cell search is successful. If the first PLMN cell search is successful, the DS layer may determine that the first PLMN is the serving PLMN for the first UE; if the first PLMN cell search fails, the DS layer may instruct the first NAS layer to reselect a PLMN that supports dual-directionality.

[0410] For example, assume that the first network selection list may include PLMN1, PLMN2, and PLMN3, where PLMN1 has a higher priority than PLMN2, which in turn has a higher priority than PLMN3. The first NAS layer may initially select PLMN1 as the first PLMN and transmit first network information to the DS layer. This first network information indicates that the first NAS layer has selected PLMN1 for the first UE. If the DS layer obtains information from the first NAS layer that PLMN1 supports dual-directional positioning, it sends first indication information to the first NAS layer, indicating that PLMN1 is accepted as the serving PLMN for the first UE. After receiving this first indication information, the first NAS layer performs a cell search based on PLMN1 and sends an indication to the DS layer regarding whether the cell search for PLMN1 is successful. If the cell search for PLMN1 is successful, the DS layer may determine that PLMN1 is the serving PLMN for the first UE. If the cell search for PLMN1 fails, the DS layer may instruct the first NAS layer to reselect a PLMN that supports dual-directional positioning.

[0411] In this implementation, the DS layer determines whether the first NAS layer needs to select a PLMN that supports dual-directionality. In this way, the first NAS layer does not need to perform this judgment process, which not only avoids the influence of the PLMN selection logic of the first NAS layer, but also helps to improve the efficiency of the first NAS in selecting the first PLMN.

[0412] In a third possible implementation manner, the method for the communication device to select the first PLMN as the serving PLMN of the first UE may also be as shown in FIG. 18 .

[0413] S1801: The first NAS layer transmits second network information to the DS layer, where the second network information indicates that the PLMN selected by the first NAS layer for the first UE is a fourth PLMN. Correspondingly, the DS layer receives the second network information.

[0414] Optionally, the second network information may further include indication information of whether the fourth PLMN supports dual-directionality.

[0415] Optionally, when the communication device is in dual-directional mode or the communication device is authorized for dual-directional operation, the DS layer requests the first NAS layer to obtain the PLMN selected for the first UE or obtain the search PLMN, and the first NAS layer then transmits the second network information to the DS layer.

[0416] In this implementation, the PLMN selected by the first NAS layer for the first UE may be a search PLMN or a serving PLMN.

[0417] In this implementation, the DS layer may obtain information that the fourth PLMN does not support dual-directional communication from the first NAS layer.

[0418] Optionally, when the PLMN selected by the first NAS layer for the first UE is a search PLMN, the first NAS layer may select a PLMN with the highest priority as the fourth PLMN based on the first network selection list.

[0419] For example, assuming that the first network selection list may include PLMN1, PLMN2, and PLMN3, where the priority of PLMN1 is higher than the priority of PLMN2, and the priority of PLMN2 is higher than the priority of PLMN3, the first NAS layer may first select PLMN1 as the fourth PLMN and transmit second network information to the DS layer, where the second network information indicates that the PLMN selected by the first NAS layer for the first UE is PLMN1.

[0420] Optionally, when the PLMN selected by the first NAS layer for the first UE is a serving PLMN, the first NAS layer may select a PLMN with the highest priority and successful cell search as the fourth PLMN based on the first network selection list.

[0421] For example, assume that the first network selection list may include PLMN1, PLMN2, and PLMN3, where the priority of PLMN1 is higher than the priority of PLMN2, and the priority of PLMN2 is higher than the priority of PLMN3. If the cell search for PLMN1 is successful, the first NAS layer may select PLMN1 as the fourth PLMN and transmit second network information to the DS layer. The second network information indicates that the first NAS layer has selected PLMN1 for the first UE.

[0422] S1802: If the fourth PLMN does not support the dual-directional function, the DS layer sends a second indication message to the first NAS layer. The second indication message indicates that the fourth PLMN is not accepted as the serving PLMN for the first UE or instructs the first NAS layer to select a PLMN that supports dual-directional function. In response, the first NAS layer receives the second indication message.

[0423] Optionally, the DS layer sends the second indication information to the first NAS layer only when the communication device is in the dual-directional mode or the communication device is authorized for dual-directional operation.

[0424] S1803: The first NAS layer selects the first PLMN as the serving PLMN for the first UE according to the second indication information.

[0425] In this method, the first NAS layer may select the PLMN with the highest priority and successful cell search from among the other PLMNs based on the first network selection list. The other PLMN may be any PLMN other than the fourth PLMN in the first network selection list.

[0426] Optionally, the first NAS layer further retransmits second network information to the DS layer, where the second network information indicates the PLMN reselected by the first NAS layer for the first UE.

[0427] In this implementation, the DS layer determines whether the first NAS layer needs to select a PLMN that supports dual-directionality. In this way, the first NAS layer does not need to perform this judgment process, which not only avoids the influence of the PLMN selection logic of the first NAS layer, but also helps to improve the efficiency of the first NAS in selecting the first PLMN.

[0428] S1502: The communication device selects a second PLMN as a serving PLMN for a second UE, where the second PLMN is a PLMN supporting dual-directional directionality.

[0429] In this method, the method for the communication device to select the second PLMN as the serving PLMN for the second UE may refer to the method for the communication device to select the first PLMN as the serving PLMN for the first UE in S1501 above, which will not be repeated here.

[0430] When both the first PLMN and the second PLMN selected by the communication device support dual-direction, the communication device can implement the dual-direction feature, for example, the communication device can control service direction and service switching processes to complete the transmission of service data.

[0431] In this application, the communication device can coordinate the PLMN selection of the two UEs through the DS layer. The DS layer of the communication device controls the NAS layer of the two UEs to select a PLMN that supports dual-directionality, avoiding direct interaction between the NAS layers of the two UEs and avoiding additional impact on the NAS layers of the two UEs.

[0432] Optionally, the first PLMN and the second PLMN may also be different PLMNs.

[0433] In this implementation, the first PLMN and the second PLMN selected by the communication device are different. When the network connected to one UE in the communication device is disconnected, the other UE can still be connected to the network, avoiding the situation where both UEs in the communication device are disconnected from the network due to a network failure or connection interruption, which is beneficial to improving the reliability of the communication device's access to the network.

[0434] Optionally, the DS layer determines whether the first PLMN and the second PLMN are different PLMNs; if the first PLMN and the second PLMN are different PLMNs, the DS layer determines to select the first PLMN as the service PLMN of the first terminal, and determines to select the second PLMN as the service PLMN of the second terminal; if the first PLMN and the second PLMN are the same PLMN, the DS layer sends a third indication message to the first NAS layer or the second NAS layer, and the third indication message is used to indicate reselection of the PLMN.

[0435] In this method, the DS layer may send the third indication information to the first NAS layer or the second NAS layer according to the priority of the first UE and the second UE. For example, the DS layer may send the third indication information to the NAS layer of the UE with lower priority.

[0436] Assuming that the first UE is a primary terminal and the second UE is a secondary terminal, or in other words, the priority of the first UE is higher than that of the second UE, the DS layer may send third indication information to the second NAS layer.

[0437] In this method, the first PLMN and the second PLMN selected by the communication device are different. When the network connected to one UE in the communication device is disconnected, the other UE can still be connected to the network, avoiding the situation where both UEs in the communication device are disconnected from the network due to a network failure or connection interruption, which is conducive to improving the reliability of the communication device's access to the network.

[0438] In the method, the communication device is in a bidirectional mode or the communication device is authorized for bidirectional operation.

[0439] When the communication device is in the bidirectional mode or the communication device is authorized for bidirectional operation, the communication device can select the first PLMN as the serving PLMN for the first UE and select the second PLMN as the serving PLMN for the second UE.

[0440] The operations of the communication device determining whether it is in the dual-directional mode and whether the communication device is authorized for dual-directional operation can refer to the relevant content in the above embodiments and will not be repeated here.

[0441] In this method, the communication device can enter the dual-directional mode or perform the dual-directional operation only when both the first PLMN and the second PLMN support dual-directional.

[0442] The communication device performing the dual-directional operation may include: controlling service direction and controlling service switching.

[0443] The communication device controlling service direction can be understood as: when a target service is triggered, the communication device can select a specific UE to transmit the target service. The communication device controlling service switching can be understood as: the communication device transfers the service transmitted through one UE to the service transmitted through another UE.

[0444] The method for controlling service orientation by a communication device may refer to the method for controlling service orientation by a communication device in the aforementioned embodiment, which will not be described in detail here.

[0445] The method for controlling service switching by a communication device may refer to the method for controlling service switching by a communication device in the aforementioned embodiment, which will not be described in detail here.

[0446] In the embodiments of the present application, a communication device including a first UE and a second UE is used as an example for illustration. The two UEs may be two devices / apparatuses. Alternatively, the two UEs included in the communication device may be two SIM cards, for example, the first UE may be a first SIM card, and the second UE may be a second SIM card. Alternatively, the communication device may be a UE, and the UE may include two SIM cards, with the first UE corresponding to the first SIM card and the second UE corresponding to the second SIM card. Accordingly, in the embodiments of the present application, the communication device may be replaced by a UE, the UE may be replaced by a SIM card, the first UE may be replaced by the first SIM card, and the second UE may be replaced by the second SIM card. Alternatively, the communication device may be a dual-directional device, and the dual-directional device may include two SIM cards, with the first UE corresponding to the first SIM card and the second UE corresponding to the second SIM card. Accordingly, in the embodiments of the present application, the communication device may be replaced by a dual-directional device, the UE may be replaced by a SIM card, the first UE may be replaced by the first SIM card, and the second UE may be replaced by the second SIM card. Alternatively, the communication device may be a UE, and the UE may include two protocol stacks, with the first UE being replaced by the first protocol stack of the UE and the second UE being replaced by the second protocol stack of the UE.

[0447] FIG19 is a schematic diagram of the structure of a control device of a communication device according to an embodiment of the present application. As shown in FIG19 , the control device 1900 of the communication device may include a processing module 1901 .

[0448] As an example, the control device 1900 of the communication device may be used to implement the method of the embodiment shown in Figure 7. The processing module 1901 may be used to execute S701 and S702.

[0449] In this example, the control device 1900 of the communication device may be a communication device, or a chip or chip system used in the communication device.

[0450] Optionally, the control device 1900 of the communication device may further include a transceiver module 1902 .

[0451] As another example, the control device 1900 of the communication device may be used to implement the communication method of the embodiment shown in Figure 9. The processing module 1901 may be used to execute S903, and the transceiver module 1902 may be used to execute S901 and S902.

[0452] In this example, the control module 1900 of the communication device may be a logic module or software capable of implementing all or part of the functions of the communication device.

[0453] As another example, the control device 1900 of the communication device may be used to implement the communication method of the embodiment shown in Figure 10. The transceiver module 1902 may be used to execute S1001 to S1003.

[0454] In this example, the control module 1900 of the communication device may be a logic module or software capable of implementing all or part of the functions of the communication device.

[0455] As another example, the control device 1900 of the communication device may be used to implement the communication method of the embodiment shown in Figure 11. The processing module 1901 may be used to execute S1104, and the transceiver module 1902 may be used to execute S1101 to S1103.

[0456] In this example, the control module 1900 of the communication device may be a logic module or software capable of implementing all or part of the functions of the communication device.

[0457] As another example, the control device 1900 of the communication device may be used to implement the method of the embodiment shown in Figure 12. The processing module 1901 may be used to execute S1201 and S1202.

[0458] In this example, the control device 1900 of the communication device may be a communication device, or a chip or chip system used in the communication device.

[0459] As another example, the control device 1900 of the communication device may be used to implement the method of the embodiment shown in Figure 15. The processing module 1901 may be used to execute S1501 and S1502.

[0460] In this example, the control device 1900 of the communication device may be a communication device, or a chip or chip system used in the communication device.

[0461] As another example, the control device 1900 of the communication device may be used to implement the communication method of the embodiment shown in Figure 16. The processing module 1901 may be used to execute S1602, and the transceiver module 1902 may be used to execute S1601.

[0462] In this example, the control module 1900 of the communication device may be a logic module or software capable of implementing all or part of the functions of the communication device.

[0463] As another example, the control device 1900 of the communication device may be used to implement the communication method of the embodiment shown in Figure 17. The transceiver module 1902 may be used to execute S1701 and S1702.

[0464] In this example, the control module 1900 of the communication device may be a logic module or software capable of implementing all or part of the functions of the communication device.

[0465] As another example, the control device 1900 of the communication device may be used to implement the communication method of the embodiment shown in Figure 18. The processing module 1901 may be used to execute S1803, and the transceiver module 1902 may be used to execute S1801 and S1802.

[0466] In this example, the control module 1900 of the communication device may be a logic module or software capable of implementing all or part of the functions of the communication device.

[0467] Figure 20 is a schematic diagram of the structure of a control device for a communication device provided in another embodiment of the present application. As shown in Figure 20, the control device 2000 of the communication device includes a processor 2001 and an interface circuit 2002. The processor 2001 and the interface circuit 2002 are coupled to each other. It will be understood that the interface circuit 2002 can be a transceiver or an input / output interface. Optionally, the control device 2000 of the communication device may further include a memory 2003 for storing instructions executed by the processor 2001, or storing input data required by the processor 2001 to execute instructions, or storing data generated after the processor 2001 executes instructions.

[0468] As an example, the processor 2001 can be used to implement the functions of the above-mentioned processing module 1901, and the interface circuit 2002 can be used to implement the functions of the above-mentioned transceiver module 1902.

[0469] The method steps in the embodiments of the present application can be implemented by hardware or by a processor executing software instructions. The software instructions can be composed of corresponding software modules, which can be stored in a memory or any other form of storage medium well known in the art. An exemplary storage medium is coupled to the processor so that the processor can read information from the storage medium and write information to the storage medium. Of course, the storage medium can also be an integral part of the processor. The processor and the storage medium can be located in an ASIC. In addition, the ASIC can be located in a network device or a terminal. Of course, the processor and the storage medium can also be present in a network device or a terminal as discrete components.

[0470] In the present application, memory may include: cache, random access memory (RAM), flash memory, read-only memory (ROM), synchronous dynamic random access memory (SDRAM), programmable read-only memory, erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory, register, hard disk drive (HDD) or solid-state drive (SSD), mobile hard disk, or portable read-only memory (CD-ROM), etc. Memory is any other medium that can be used to carry or store desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited to this. The memory in the embodiment of the present application can also be a circuit or any other device that can realize a storage function, for storing computer programs or instructions, and / or data.

[0471] In this application, the processor may be one or more central processing units (CPUs). In the case where the processor is a CPU, the CPU may be a single-core CPU or a multi-core CPU. The processor may be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a programmable logic device (PLD), a graphics processing unit (GPU), an application-specific integrated circuit, a field programmable gate array or other programmable logic device, a discrete gate or transistor logic device, or a discrete hardware group. A general-purpose processor may be a microprocessor or any conventional processor.

[0472] In the above embodiments, all or part of the embodiments may be implemented using software, hardware, firmware, or any combination thereof. When implemented using software, all or part of the embodiments may be implemented in the form of a computer program product. The computer program product includes one or more computer programs or instructions. When the computer program or instructions are loaded and executed on a computer, the processes or functions described in the embodiments of the present application are performed in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, a network device, a user device, or other programmable device. The computer program or instructions may be stored in a computer-readable storage medium or transferred from one computer-readable storage medium to another. For example, the computer program or instructions may be transferred from one website, computer, server, or data center to another website, computer, server, or data center via wired or wireless means. The computer-readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server or data center that integrates one or more available media. The available medium may be a magnetic medium, such as a floppy disk, hard disk, or magnetic tape; an optical medium, such as a digital video disk; or a semiconductor medium, such as a solid-state drive.

[0473] An embodiment of the present application also provides a computer-readable storage medium, which stores a computer program or instructions, and the computer program or instructions are executed by a computer (e.g., a processor) to implement part or all of the steps of any method performed by any device in the embodiment of the present application.

[0474] An embodiment of the present application also provides a computer program product including a computer program or a set of instructions, which, when executed on a computer, implements part or all of the steps of any method performed by any device in the embodiment of the present application.

[0475] In the various embodiments of the present application, unless otherwise specified or there is a logical conflict, the terms and / or descriptions between different embodiments are consistent and can be referenced by each other. The technical features in different embodiments can be combined to form new embodiments according to their inherent logical relationships.

[0476] It is understood that the various numbers used in the embodiments of this application are merely for ease of description and are not intended to limit the scope of the embodiments of this application. The order of the sequence numbers of the above-mentioned processes does not necessarily imply a specific order of execution; the order of execution of the processes should be determined by their functions and inherent logic.

Claims

1. A method for controlling a communication device, characterized in that: The communication device includes a first terminal and a second terminal, and the method includes: selecting a first public land mobile network as a serving public land mobile network for the first terminal; A second public land mobile network is selected as a serving public land mobile network for the second terminal, and the first public land mobile network and the second public land mobile network are different public land mobile networks.

2. The method according to claim 1, characterized in that The selecting the second public land mobile network as the serving public land mobile network of the second terminal includes: The dual-directional layer of the communication device receives first information transmitted by a first non-access layer, where the first information instructs the first non-access layer to select a first public land mobile network as a serving public land mobile network for the first terminal, and the first non-access layer is a non-access layer for the first terminal; The dual-directional layer sends the first public land mobile network to a second non-access layer, where the second non-access layer is a non-access layer of the second terminal; The second non-access layer selects a second public land mobile network as a serving public land mobile network for the second terminal, where the second public land mobile network is different from the first public land mobile network.

3. The method according to claim 1, characterized in that The selecting the second public land mobile network as the serving public land mobile network of the second terminal includes: The dual-directional layer of the communication device receives first information transmitted by a first non-access layer, where the first information indicates that the public land mobile network selected by the first non-access layer for the first terminal is a first public land mobile network, and the first non-access layer is a non-access layer of the first terminal; The dual-directional layer receives second information transmitted by a second non-access layer, where the second information indicates that the public land mobile network selected by the second non-access layer for the second terminal is a second public land mobile network, and the second non-access layer is a non-access layer of the second terminal; If the second public land mobile network and the first public land mobile network are different public land mobile networks, third information is transmitted to the second non-access layer, where the third information indicates that the second public land mobile network is agreed to be the serving public land mobile network of the second terminal.

4. The method according to claim 1, wherein The selecting the second public land mobile network as the serving public land mobile network of the second terminal includes: The dual-directional dual-directional layer of the communication device receives first information transmitted by a first non-access layer, where the first information instructs the first non-access layer to select a first public land mobile network as a serving public land mobile network for the first terminal, and the first non-access layer is a non-access layer for the first terminal; The dual-directional layer receives second information transmitted by a second non-access layer, where the second information indicates that the public land mobile network selected by the second non-access layer for the second terminal is a third public land mobile network, and the second non-access layer is a non-access layer of the second terminal; If the third public land mobile network and the first public land mobile network are the same public land mobile network, the dual-directional layer transmits fourth information to the second non-access layer, where the fourth information indicates that the third public land mobile network is not approved as a serving public land mobile network for the second terminal or instructs the second non-access layer to reselect a public land mobile network. The second non-access layer selects a second public land mobile network as a serving public land mobile network for the second terminal according to the fourth information.

5. The method according to any one of claims 1 to 4, characterized in that The first public land mobile network and the second public land mobile network are public land mobile networks supporting dual-directional directionality.

6. The method according to claim 5, characterized in that The method further comprises: The dual-directional layer of the communication device sends fifth information to a first non-access layer and a second non-access layer respectively, wherein the fifth information requests selection of a public land mobile network supporting dual-directionality, the first non-access layer being the non-access layer of the first terminal, and the second non-access layer being the non-access layer of the second terminal; The first non-access stratum and the second non-access stratum respectively select a public land mobile network according to the fifth information.

7. The method according to claim 5, characterized in that The method further comprises: The dual-directional layer of the communication device receives sixth information transmitted by a second non-access layer, where the sixth information indicates whether the second public land mobile network supports dual-directionality, and the second non-access layer is a non-access layer of the second terminal; If the sixth information indicates that the second public land mobile network supports dual-directionality, the dual-directionality layer determines to use the second public land mobile network as a serving public land mobile network for the second terminal; If the sixth information indicates that the second public land mobile network does not support dual-directionality, the dual-directionality layer sends seventh information to the second non-access stratum, where the seventh information indicates that the second public land mobile network is not approved to be used as the serving public land mobile network of the second terminal or instructs the second non-access stratum to select a public land mobile network that supports dual-directionality; The second non-access layer reselects a public land mobile network according to the seventh information.

8. The method according to claim 7, characterized in that The seventh information further includes the first public land mobile network.

9. The method according to any one of claims 1 to 8, characterized in that The communication device is in bi-directional mode or the communication device is authorized for bi-directional operation.

10. The method according to any one of claims 1 to 9, characterized in that The first terminal is a primary terminal in the communication device, and / or the second terminal is a secondary terminal in the communication device.

11. A method for controlling a communication device, characterized in that: The communication device includes a first terminal and a second terminal, and the method includes: selecting a first public land mobile network as a serving public land mobile network for the first terminal; A second public land mobile network is selected as a serving public land mobile network for the second terminal, and the first public land mobile network and the second public land mobile network are public land mobile networks supporting bidirectional directionality.

12. The method according to claim 11, characterized in that The method further comprises: receiving, through the first terminal, information that the first public land mobile network supports bidirectional directionality; Information that the second public land mobile network supports bi-directional directionality is received through the second terminal.

13. The method according to claim 11 or 12, characterized in that The selecting the first public land mobile network as the serving public land mobile network of the first terminal includes: The dual-directional layer of the communication device sends a first request message to a first non-access layer, wherein the first request message requests selection of a public land mobile network supporting dual-directionality, and the first non-access layer is a non-access layer of the first terminal; The first non-access layer selects a first public land mobile network as a serving public land mobile network for the first terminal according to the first request information.

14. The method according to claim 11 or 12, characterized in that The selecting the first public land mobile network as the serving public land mobile network of the first terminal includes: The dual-directional layer of the communication device receives first network information transmitted by a first non-access layer, where the first network information indicates that the public land mobile network selected by the first non-access layer for the first terminal is a first public land mobile network, and the first non-access layer is a non-access layer of the first terminal; If the first public land mobile network supports a dual-directional function, the dual-directional layer sends first indication information to the first non-access layer, where the first indication information indicates that the first public land mobile network is allowed to be used as a serving public land mobile network for the first terminal.

15. The method according to claim 11 or 12, characterized in that The selecting the first public land mobile network as the serving public land mobile network of the first terminal includes: The dual-directional layer of the communication device receives second network information transmitted by the first non-access layer, where the second network information indicates that the public land mobile network selected by the first non-access layer for the first terminal is a fourth public land mobile network, and the first non-access layer is the non-access layer of the first terminal; If the fourth public land mobile network does not support the dual-directional function, the dual-directional layer sends second indication information to the first non-access layer, where the second indication information indicates that the fourth public land mobile network is not approved as the serving public land mobile network of the first terminal or instructs the first non-access layer to select a public land mobile network that supports dual-directional function; The first non-access layer selects the first public land mobile network as the serving public land mobile network of the first terminal according to the second indication information.

16. The method according to any one of claims 11 to 15, characterized in that The first public land mobile network and the second public land mobile network are different public land mobile networks.

17. The method according to claim 16, characterized in that The method further comprises: determining, by the dual-directional layer of the communication device, whether the first public land mobile network and the second public land mobile network are different public land mobile networks; If the first public land mobile network and the second public land mobile network are different public land mobile networks, the bidirectional layer determines to select the first public land mobile network as a serving public land mobile network for the first terminal, and determines to select the second public land mobile network as a serving public land mobile network for the second terminal; If the first public land mobile network and the second public land mobile network are the same public land mobile network, the dual-directional layer sends third indication information to the first non-access layer or the second non-access layer, where the third indication information is used to instruct reselection of the public land mobile network.

18. The method according to any one of claims 11 to 17, characterized in that The method further comprises: Determining a first target terminal, where the first target terminal is one of the first terminal and the second terminal; The target service of the communication device is transmitted based on the first target terminal.

19. The method according to claim 18, characterized in that The determining the first target terminal includes: Acquire a service orientation policy, the service orientation policy including at least one service and a public land mobile network and / or wireless access type preferentially associated with each of the at least one service, the at least one service including the target service; Acquire first access information and second access information, where the first access information includes a public land mobile network and / or RAT accessed by the first terminal, and the second access information includes a public land mobile network and / or wireless access type accessed by the second terminal; A first target terminal is determined based on the first access information, the second access information, and the service orientation policy, wherein the public land mobile network accessed by the first target terminal is the public land mobile network preferentially associated with the target service, and / or the wireless access type accessed by the first target terminal is the wireless access type preferentially associated with the target service.

20. The method according to claim 18, wherein The determining the first target terminal includes: The dual-directional layer of the communication device obtains a service direction policy from a first non-access stratum or a second non-access stratum, where the service direction policy includes at least one service and a public land mobile network and / or a wireless access type preferentially associated with each of the at least one service, the at least one service includes the target service, the first non-access stratum is a non-access stratum of the first terminal, and the second non-access stratum is a non-access stratum of the second terminal; The dual-directional layer obtains first access information from the first non-access layer or the first access layer, where the first access information includes a public land mobile network and / or a wireless access type accessed by the first terminal, and the first access layer is an access layer of the first terminal; The dual-directional layer obtains second access information from the second non-access layer or the second access layer, where the second access information includes a public land mobile network and / or a wireless access type accessed by the second terminal, and the second access layer is an access layer of the second terminal; The dual-directional layer determines the first target terminal based on the first access information, the second access information, and the service orientation policy, the public land mobile network accessed by the first target terminal is the public land mobile network preferentially associated with the target service, and / or the wireless access type accessed by the first target terminal is the wireless access type preferentially associated with the target service.

21. The method according to any one of claims 18 to 20, characterized in that The method further comprises: The target service is transmitted through a second target terminal according to a connection state of the first target terminal, where the second target terminal is a terminal other than the first target terminal between the first terminal and the second terminal.

22. The method according to any one of claims 18 to 20, characterized in that The method further comprises: The dual-directional layer of the communication device obtains the connection status of the first target terminal from the non-access layer of the first target terminal or the access layer of the first target terminal; The dual-directional layer determines, according to the connection status of the first target terminal, to transmit the target service based on a second target terminal, where the second target terminal is a terminal other than the first target terminal between the first terminal and the second terminal.

23. The method according to any one of claims 11 to 22, characterized in that The communication device is in bi-directional mode or the communication device is authorized for bi-directional operation.

24. A control device for a communication device, characterized in that: The method comprises functional modules for implementing the method according to any one of claims 1 to 23.

25. A control device for a communication device, characterized in that: The device comprises a processor configured to execute a computer program or instruction stored in a memory and / or a logic circuit so as to cause the device to perform the method according to any one of claims 1 to 23.

26. The device according to claim 25, characterized in that The control device of the communication device further comprises a memory, which is used to store the computer program or instructions.

27. A computer-readable storage medium, characterized in that The computer-readable storage medium stores computer-executable instructions, and when the computer-executable instructions are executed on a control device of a communication device, the method according to any one of claims 1 to 23 is implemented.

28. A computer program product, characterized in that The computer program product comprises instructions for implementing the method according to any one of claims 1 to 23.

29. A communication system, characterized in that: The method comprises a communication device configured to perform the method according to any one of claims 1 to 23.

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