Registration access method and apparatus

Abstract

Disclosed in the embodiments of the present application are a registration access method and apparatus. The method comprises: executing PLMN selection to search for an available PLMN; on the basis of the available PLMN and PLMN information stored in each of a plurality of SIM cards, selecting a target SIM card from among the plurality of SIM cards; and initiating registration access on the basis of security context stored in the target SIM card. By using the embodiments of the present application, one SIM card is selected by means of the found available PLMN and the PLMN information stored in each SIM card, and then registration is initiated by means of the security context in the selected SIM card, so as to prevent registration process failures caused by the available PLMN differing from a registered PLMN stored in the SIM card, improve the success rate of registration, and prevent re-authorization and re-authentication or prevent the security context from being acquired from a mobility management network element of a previous PLMN, thereby improving registration efficiency and reducing signaling overhead.

Description

A method and apparatus for registering access

[0001] The present application claims priority to the Chinese patent application No. 202410904463.4, filed on July 5, 2024, and entitled "A method and apparatus for registering access", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present application relates to the field of communication technology, and in particular to a method and apparatus for registering access. BACKGROUND

[0003] The 3rd generation partnership project (3GPP) defines a dual steer device (DS device), which refers to a device supporting steering and switching of user plane data in dual 3GPP access networks. The dual steer device can be a single user equipment (UE) transmitting non-synchronized data on dual 3GPP networks, or dual UEs transmitting synchronized data on dual 3GPP networks. If it is a single UE scenario, it can be referred to as a dual-universal subscriber identity module (Dual-USIM) dual steer UE, which has two different subscriber identity module (SIM) cards. The UE can connect to each 3GPP access network through each SIM card. If it is a dual UE scenario, it can be referred to as a single-universal subscriber identity module (Single-USIM) dual steer UE, that is, each UE is connected to a separate 3GPP access network as part of the dual steer.

[0004] In the Dual-USIM DualSteer UE or Single-USIM DualSteer UE scenario, when one of the SIM cards or one of the UEs initiates registration, authentication, authentication, and security activation will be initiated for the selected SIM card, and when deregistration or shutdown occurs, the current security context will be stored to the SIM card, so the DualSteer device will maintain two independent security contexts. Since the DualSteer Device contains two UEs or two SIM cards, when the Dualsteer Device is in the shutdown or dual-access deregistration state and is ready to initiate registration access, it is necessary to select which UE or which SIM card to initiate registration.

[0005] Currently, the selection of the UE or the SIM card is based on the configuration method, and a specific UE is configured as the primary UE, or a specific SIM card is set as the primary SIM card. When it is necessary to select the UE or the SIM card to initiate registration access, the primary UE or the primary SIM card is selected, and then public land mobile network (PLMN) selection is performed based on the selected UE or the SIM card. However, using this configuration method may cause the registration initiation process to fail, or re-authentication is required, which will delay registration and increase signaling overhead. SUMMARY

[0006] Embodiments of the present application provide a registration access method and device, which can improve the success rate of registration, improve the efficiency of registration, and reduce signaling overhead.

[0007] In a first aspect, embodiments of the present application provide a registration access method, which can be applied to the terminal side, for example, a first device or a communication module in the first device, or a circuit or chip responsible for communication functions in the first device (such as a modem chip, also known as a baseband chip, or a system on chip (SoC) chip or a system in package (SIP) chip containing a modem core). Taking the case where the method is applied to the first device, the first device includes multiple SIM cards, and the method includes:

[0008] performing public land mobile network (PLMN) selection to find available PLMNs; selecting a target SIM card from the multiple SIM cards according to the available PLMNs and PLMN information stored in each of the multiple SIM cards; and initiating registration access based on the security context stored in the target SIM card.

[0009] In the scenario that the first device contains multiple SIM cards, one of the SIM cards is selected by searching the available PLMN and the PLMN information stored by each SIM card, and then the registration is initiated by the security context of the selected SIM card, so that the registration failure caused by the difference between the available PLMN and the registration PLMN stored by the SIM card is avoided, the success rate of registration is improved, re-authentication or obtaining the security context from the mobility management network element of the previous PLMN is avoided, the registration efficiency is improved, and the signaling overhead is reduced.

[0010] In a possible design, the multiple SIM cards belong to the same operator.

[0011] In a possible design, the PLMN information includes a registration PLMN.

[0012] In a possible design, the first device is in a de-registered state on the multiple SIM cards.

[0013] In a possible design, the available PLMN is searched based on PLMN selection based on a PLMN list, and the PLMN list includes at least one PLMN.

[0014] In a possible design, the available PLMN is searched by selecting a PLMN from the PLMN list based on the priority of each PLMN in the PLMN list.

[0015] In a possible design, the PLMN list includes at least one of the following PLMNs: a home public land mobile network (HPLMN), an equivalent home public land mobile network (EHPLMN), a user-controlled public land mobile network (UPLMN), an operator-controlled public land mobile network (OPLMN), or another PLMN.

[0016] In a possible design, when only one SIM card of the multiple SIM cards stores PLMN information, the SIM card storing the PLMN information is selected as the target SIM card. The registration is initiated by the security context of the selected SIM card storing the PLMN information, so that the success rate of registration is ensured.

[0017] In a possible design, when the available PLMN is the same as or different from the registration PLMN stored by each SIM card, one SIM card is selected from the multiple SIM cards as the target SIM card, or a primary SIM card is selected from the multiple SIM cards as the target SIM card.

[0018] In a possible design, when the available PLMN is the same as a registration PLMN stored by a first SIM card in the plurality of SIM cards and is different from a registration PLMN stored by each of the other SIM cards in the plurality of SIM cards except the first SIM card, the first SIM card is selected as the target SIM card. By initiating registration using the security context of the SIM card whose stored registration PLMN is the same as the available PLMN, failure of the registration procedure caused by the available PLMN being different from the registration PLMN stored by the SIM card is avoided, the success rate of registration is improved, re-authentication or obtaining of the security context from a mobility management network element of a previous PLMN is avoided, the registration efficiency is improved, and signaling overhead is reduced.

[0019] In a possible design, when the available PLMN is the same as or different from the registration PLMN stored by each of the SIM cards, timestamp information of each of the plurality of SIM cards is obtained, the timestamp information including a time point at which the SIM card was last deregistered; and the target SIM card is selected from the plurality of SIM cards according to the timestamp information. In the case where the registration PLMN stored by each of the SIM cards is the same as or different from the available PLMN, the SIM card is selected according to the timestamp information to initiate registration, so that deletion of the security context of the SIM card due to time limitation is avoided, the success rate of registration is improved, re-authentication or obtaining of the security context from a mobility management network element of a previous PLMN is avoided, the registration efficiency is improved, and signaling overhead is reduced.

[0020] In a possible design, if the timestamp information of a first SIM card in the plurality of SIM cards is later than the timestamp information of each of the other SIM cards except the first SIM card, the first SIM card is selected as the target SIM card. By selecting the SIM card that was last deregistered later to initiate registration, deletion of the security context of the SIM card due to time limitation is avoided, the success rate of registration is improved, re-authentication or obtaining of the security context from a mobility management network element of a previous PLMN is avoided, the registration efficiency is improved, and signaling overhead is reduced.

[0021] In a possible design, when the available PLMN is the same as or different from the registered PLMN stored by each SIM card, timestamp information and duration information of each SIM card in the plurality of SIM cards are acquired, the timestamp information includes a time point at which the last de-registration of each SIM card is performed, and the duration information includes a duration for which the network device maintains a security context corresponding to each SIM card; and the target SIM card is selected from the plurality of SIM cards according to the timestamp information and the duration information. In the case where the registered PLMN stored by each SIM card is the same as or different from the available PLMN, the SIM card is selected according to the timestamp information and the duration information to initiate registration, thereby avoiding deletion of the security context of the SIM card due to time limit, improving the success rate of registration, avoiding re-authentication or obtaining the security context from a mobility management network element of a previous PLMN, improving the registration efficiency, and reducing signaling overhead.

[0022] In a possible design, a first difference value corresponding to each SIM card is calculated by subtracting the timestamp information of each SIM card from a current time point; a second difference value corresponding to each SIM card is calculated by subtracting the first difference value corresponding to each SIM card from the duration information of each SIM card; and the SIM card with the largest second difference value is selected as the target SIM card from the plurality of SIM cards. By selecting the SIM card with a longer duration for which the network maintains the security context and a later time point at which the last de-registration is performed to initiate registration, deletion of the security context of the SIM card due to time limit is avoided, the success rate of registration is improved, re-authentication or obtaining the security context from a mobility management network element of a previous PLMN is avoided, the registration efficiency is improved, and signaling overhead is reduced.

[0023] In a second aspect, an embodiment of the present application provides a registration access method, which can be applied to a terminal side, for example, a first device or a communication module in the first device, or a circuit or chip responsible for communication function in the first device. Taking the case where the method is applied to the first device as an example, the first device includes a plurality of terminal devices, and the method includes the following steps.

[0024] An available public land mobile network (PLMN) is acquired by performing PLMN selection and search; a target device is selected from the plurality of terminal devices according to the available PLMN and PLMN information stored by each terminal device in the plurality of terminal devices; and registration access is initiated based on a security context stored by the target device.

[0025] In a scenario where the first device includes multiple terminal devices, the first device selects one of the terminal devices through available PLMNs and PLMN information stored by each terminal device, and then initiates registration through a security context of the selected terminal device, thereby avoiding a situation where the available PLMN is different from a registration PLMN stored by a terminal device, and registration fails, improving the success rate of registration, avoiding re-authentication and re-accreditation or obtaining a security context from a mobility management network element of a previous PLMN, improving registration efficiency, and reducing signaling overhead.

[0026] In a possible design, the multiple SIM cards included in the multiple terminal devices belong to a same operator.

[0027] In a possible design, the PLMN information includes a registration PLMN.

[0028] In a possible design, the multiple terminal devices are all in a deregistered state.

[0029] In a possible design, the available PLMNs are selected from a PLMN list, and the PLMN list includes at least one PLMN.

[0030] In a possible design, the available PLMNs are selected based on priorities of each PLMN in the PLMN list.

[0031] In a possible design, the PLMN list includes at least one of the following PLMNs: a home public land mobile network (HPLMN), an equivalent home public land mobile network (EHPLMN), a user-controlled public land mobile network (UPLMN), an operator-controlled public land mobile network (OPLMN), or another PLMN.

[0032] In a possible design, a first terminal device is selected from the multiple terminal devices, and the available PLMNs are obtained through a public land mobile network (PLMN) selection lookup performed by the first terminal device. The PLMN selection lookup is performed by a selected terminal device from the multiple terminal devices.

[0033] In a possible design, when only one terminal device from the multiple terminal devices stores PLMN information, the terminal device storing the PLMN information is selected as the target device. The registration is initiated through a security context of the terminal device storing the PLMN information, thereby guaranteeing the success rate of registration.

[0034] In a possible design, when the available PLMNs are all the same as or all different from registration PLMNs stored by each terminal device, a terminal device is selected from the multiple terminal devices as the target device, or a master device is selected from the multiple terminal devices as the target device.

[0035] In a possible design, when the available PLMN is the same as the registration PLMN stored by a first terminal device in the plurality of terminal devices and is different from the registration PLMN stored by other terminal devices in the plurality of terminal devices except the first terminal device, the first terminal device is selected as the target device. By initiating registration using the security context of the terminal device whose stored registration PLMN is the same as the available PLMN, failure of the registration procedure caused by the available PLMN being different from the registration PLMN stored by the SIM card is avoided, the success rate of registration is improved, re-authentication or obtaining of the security context from the mobility management network element of the previous PLMN is avoided, the registration efficiency is improved, and signaling overhead is reduced.

[0036] In a possible design, when the available PLMN is the same as or different from the registration PLMN stored by each terminal device in the plurality of terminal devices, timestamp information of each terminal device in the plurality of terminal devices is obtained, and the timestamp information includes a time point at which the terminal device last deregistered; and the target device is selected from the plurality of terminal devices according to the timestamp information. In the case where the registration PLMN stored by each terminal device is the same as or different from the available PLMN, the terminal device is selected according to the timestamp information to initiate registration, the security context of the terminal device is avoided from being deleted due to time limitation, the success rate of registration is improved, re-authentication or obtaining of the security context from the mobility management network element of the previous PLMN is avoided, the registration efficiency is improved, and signaling overhead is reduced.

[0037] In a possible design, if the timestamp information of a first terminal device in the plurality of terminal devices is later than the timestamp information of other terminal devices except the first terminal device, the first terminal device is selected as the target device. By selecting the terminal device that last deregistered later to initiate registration, the security context of the terminal device is avoided from being deleted due to time limitation, the success rate of registration is improved, re-authentication or obtaining of the security context from the mobility management network element of the previous PLMN is avoided, the registration efficiency is improved, and signaling overhead is reduced.

[0038] In a possible design, when the available PLMN is the same as or different from the registered PLMN stored by each terminal device, timestamp information and time length information of each terminal device in the plurality of terminal devices are acquired, the timestamp information includes a time point at which the last de-registration of the terminal device is performed, and the time length information includes a time length for which the network device maintains a security context of the terminal device; and the target device is selected from the plurality of terminal devices according to the timestamp information and the time length information. In the case where the registered PLMN stored by each terminal device is the same as or different from the available PLMN, the terminal device is selected to initiate registration by using the timestamp information and the time length information, so that the security context of the terminal device is prevented from being deleted due to time limit, the success rate of registration is improved, re-authentication is avoided, and the security context is prevented from being acquired from a mobility management network element of a previous PLMN, thereby improving the registration efficiency and reducing signaling overhead.

[0039] In a possible design, a first difference value corresponding to each terminal device is calculated by subtracting the timestamp information of the terminal device from a current time point; a second difference value corresponding to each terminal device is calculated by subtracting the first difference value corresponding to the terminal device from the time length information of the terminal device; and the terminal device with the largest second difference value is selected as the target device from the plurality of terminal devices. By selecting the terminal device with a longer time length for which the network maintains the security context and a later time point at which the last de-registration is performed to initiate registration, the security context of the terminal device is prevented from being deleted due to time limit, the success rate of registration is improved, re-authentication is avoided, and the security context is prevented from being acquired from a mobility management network element of a previous PLMN, thereby improving the registration efficiency and reducing signaling overhead.

[0040] In a third aspect, an embodiment of the present application provides a registration access method, which can be applied to a terminal side, for example, a first terminal device in a first device or a communication module of the first terminal device in the first device, or a circuit or chip responsible for a communication function in the first terminal device. Taking the case where the method is applied to the first terminal device as an example, the first device includes a plurality of terminal devices, and the method includes the following steps.

[0041] performing a public land mobile network (PLMN) selection to find an available PLMN; selecting a target device from the plurality of terminal devices according to the available PLMN and PLMN information stored by the first terminal device; and initiating registration access based on a stored security context of the target device.

[0042] In a scenario where the first device includes multiple terminal devices, the first terminal device selects one of the terminal devices through a PLMN available to the first terminal device and PLMN information stored by the first terminal device, initiates registration through a security context of the selected terminal device, avoids a registration failure caused by a difference between the PLMN available and the registration PLMN stored by the terminal device, improves a success rate of registration, avoids re-authentication or obtaining a security context from a mobility management network element of a previous PLMN, improves registration efficiency, and reduces signaling overhead.

[0043] In a possible design, the multiple SIM cards included in the multiple terminal devices belong to a same operator.

[0044] In a possible design, the PLMN information includes a registration PLMN.

[0045] In a possible design, the multiple terminal devices are all in a deregistered state.

[0046] In a possible design, the PLMN available is found based on PLMN selection based on a PLMN list, and the PLMN list includes at least one PLMN.

[0047] In a possible design, the PLMN available is selected from the PLMN list based on a priority of each PLMN in the PLMN list.

[0048] In a possible design, the PLMN list includes at least one of the following PLMNs: a home public land mobile network (HPLMN), an equivalent home public land mobile network (EHPLMN), a user control public land mobile network (UPLMN), an operator control public land mobile network (OPLMN), or another PLMN.

[0049] In a possible design, when the PLMN available is the same as the registration PLMN stored by the first terminal device, the first terminal device is selected as the target device. That is, if the first terminal device determines that the PLMN available is the same as the registration PLMN stored by the first terminal device, the first terminal device does not need to query PLMN information stored by another terminal device, and directly initiates registration access, thereby avoiding querying PLMN information stored by other terminal devices and improving registration efficiency.

[0050] In a possible design, when the available PLMN is different from the registered PLMN stored by the first terminal device, the PLMN information stored by each of the terminal devices in the plurality of terminal devices is obtained; and the target device is selected from the plurality of terminal devices according to the available PLMN and the PLMN information stored by each of the terminal devices.

[0051] In a possible design, when the registered PLMN stored by a second terminal device in the plurality of terminal devices is the same as the available PLMN, the second terminal device is selected as the target device. The security context of the terminal device whose stored registered PLMN is the same as the available PLMN is used to initiate registration, so that the registration procedure is not failed due to the difference between the available PLMN and the registered PLMN stored by the SIM card, the success rate of registration is improved, re-authentication is avoided, and the security context is not obtained from a mobility management network element of a previous PLMN, the registration efficiency is improved, and the signaling overhead is reduced.

[0052] In a possible design, when the registered PLMN stored by each of the terminal devices in the plurality of terminal devices is different from the available PLMN, the timestamp information of each of the terminal devices is obtained, the timestamp information including a time point at which the terminal device was last deregistered; and the target device is selected from the plurality of terminal devices according to the timestamp information. In the case where the registered PLMN stored by each of the terminal devices is different from the available PLMN, the terminal device is selected according to the timestamp information and time length information to initiate registration, so that the security context of the terminal device is not deleted due to time limitation, the success rate of registration is improved, re-authentication is avoided, and the security context is not obtained from a mobility management network element of a previous PLMN, the registration efficiency is improved, and the signaling overhead is reduced.

[0053] In a possible design, if the timestamp information of a first terminal device in the plurality of terminal devices is later than the timestamp information of a second terminal device, the first terminal device is selected as the target device; or if the timestamp information of the first terminal device is earlier than the timestamp information of the second terminal device, the second terminal device is selected as the target device.

[0054] In a possible design, when the registered PLMN stored by each terminal device in the plurality of terminal devices is different from the available PLMN, the timestamp information and the time length information of each terminal device are acquired, the timestamp information includes a time point at which the each terminal device last deregisters, and the time length information includes a time length for which the network device maintains a security context of the each terminal device; and the target device is selected from the plurality of terminal devices according to the timestamp information and the time length information. In the case where the registered PLMN stored by each terminal device is different from the available PLMN, the terminal device is selected to initiate registration according to the timestamp information and the time length information, so that the security context of the terminal device is prevented from being deleted due to time limitation, the success rate of registration is improved, re-authentication or obtaining of the security context from a mobility management network element of a previous PLMN is avoided, the registration efficiency is improved, and signaling overhead is reduced.

[0055] In a possible design, a first difference value corresponding to each terminal device is calculated by subtracting the timestamp information of the each terminal device from a current time point; a second difference value corresponding to the each terminal device is calculated by subtracting the first difference value corresponding to the each terminal device from the time length information of the each terminal device; and the terminal device with the largest second difference value is selected as the target device from the plurality of terminal devices. The terminal device with a longer time length for which a network maintains a security context and a later time at which the terminal device last deregisters is selected to initiate registration, so that the security context of the terminal device is prevented from being deleted due to time limitation, the success rate of registration is improved, re-authentication or obtaining of the security context from a mobility management network element of a previous PLMN is avoided, the registration efficiency is improved, and signaling overhead is reduced.

[0056] In a possible design, if the second terminal device is selected as the target device from the plurality of terminal devices, first indication information is sent, where the first indication information is used to instruct the second terminal device to initiate registration access.

[0057] In a fourth aspect, an embodiment of the present application provides a registration access apparatus, which has the functions of the first aspect, for example, the registration access apparatus includes modules or units or means corresponding to the operations of the first aspect, and the modules or units or means can be implemented by software, or by hardware, or by a combination of software and hardware. The apparatus includes:

[0058] The searching module is configured to search for an available PLMN according to a public land mobile network (PLMN) selection.

[0059] The selecting module is configured to select a target SIM card from the plurality of SIM cards according to the available PLMN and the PLMN information stored in each of the plurality of SIM cards.

[0060] The registering module is configured to initiate registration access based on the security context stored in the target SIM card.

[0061] In a possible design, the plurality of SIM cards belong to a same operator.

[0062] In a possible design, the PLMN information includes a registered PLMN.

[0063] In a possible design, the first device is in a de-registered state on the plurality of SIM cards.

[0064] In a possible design, the finding module is further configured to find the available PLMN based on PLMN selection according to a PLMN list, the PLMN list including at least one PLMN.

[0065] In a possible design, the finding module is further configured to find the available PLMN by selecting a PLMN from the PLMN list according to a priority of each PLMN in the PLMN list.

[0066] In a possible design, the PLMN list includes at least one of the following PLMNs: a home public land mobile network (HPLMN), an equivalent home public land mobile network (EHPLMN), a user control public land mobile network (UPLMN), an operator control public land mobile network (OPLMN), or another PLMN.

[0067] In a possible design, the selecting module is further configured to select, when only one SIM card in the plurality of SIM cards stores PLMN information, the SIM card storing the PLMN information as the target SIM card.

[0068] In a possible design, the selecting module is further configured to select, when the available PLMN is the same as or different from the registered PLMN stored in each of the plurality of SIM cards, a SIM card from the plurality of SIM cards as the target SIM card or select a primary SIM card from the plurality of SIM cards as the target SIM card.

[0069] In a possible design, the selecting module is further configured to select, when the available PLMN is the same as the registered PLMN stored in a first SIM card in the plurality of SIM cards and different from the registered PLMN stored in other SIM cards in the plurality of SIM cards except the first SIM card, the first SIM card as the target SIM card.

[0070] In a possible design, the selection module is further configured to: when the available PLMN is the same as or different from the registered PLMN stored by each SIM card, acquire timestamp information of each SIM card in the plurality of SIM cards, the timestamp information comprising a time point of last de-registration of each SIM card; and select the target SIM card from the plurality of SIM cards according to the timestamp information.

[0071] In a possible design, the selection module is further configured to: if the timestamp information of a first SIM card in the plurality of SIM cards is later than the timestamp information of other SIM cards except the first SIM card, select the first SIM card as the target SIM card.

[0072] In a possible design, the selection module is further configured to: when the available PLMN is the same as or different from the registered PLMN stored by each SIM card, acquire timestamp information and duration information of each SIM card in the plurality of SIM cards, the timestamp information comprising a time point of last de-registration of each SIM card, and the duration information comprising a duration for which a network device maintains a security context corresponding to each SIM; and select the target SIM card from the plurality of SIM cards according to the timestamp information and the duration information.

[0073] In a possible design, the selection module is further configured to: subtract the timestamp information of each SIM card from a current time point to obtain a first difference value corresponding to each SIM card; subtract the first difference value corresponding to each SIM card from the duration information of each SIM card to obtain a second difference value corresponding to each SIM card; and select a SIM card with the largest second difference value from the plurality of SIM cards as the target SIM card.

[0074] The operations and beneficial effects of the registration access apparatus can refer to the method and beneficial effects of the first aspect, and details are not repeated.

[0075] In a fifth aspect, an embodiment of the present application provides a registration access apparatus, which has the functions of the second aspect, for example, the registration access apparatus comprises a module or unit or means corresponding to the operations of the second aspect, which can be implemented by software, or by hardware, or by a combination of software and hardware. The apparatus comprises:

[0076] The searching module is configured to acquire an available PLMN for performing a public land mobile network (PLMN) selection search.

[0077] The selecting module is configured to select a target device from the plurality of terminal devices according to the available PLMN and the PLMN information stored in each terminal device of the plurality of terminal devices.

[0078] The registering module is configured to initiate registration access based on the security context stored in the target device.

[0079] In a possible design, the plurality of SIM cards included in the plurality of terminal devices belong to a same operator.

[0080] In a possible design, the PLMN information includes a registered PLMN.

[0081] In a possible design, the plurality of terminal devices are all in a de-registered state.

[0082] In a possible design, the available PLMN is selected from a PLMN list, and the PLMN list includes at least one PLMN.

[0083] In a possible design, the available PLMN is selected based on a priority of each PLMN in the PLMN list.

[0084] In a possible design, the PLMN list includes at least one of the following PLMNs: a home public land mobile network (HPLMN), an equivalent home public land mobile network (EHPLMN), a user-controlled public land mobile network (UPLMN), an operator-controlled public land mobile network (OPLMN), or another PLMN.

[0085] In a possible design, the searching module is further configured to select a first terminal device from the plurality of terminal devices, and to acquire the available PLMN obtained by the first terminal device performing a public land mobile network (PLMN) selection search.

[0086] In a possible design, the selecting module is further configured to, when only one terminal device of the plurality of terminal devices stores PLMN information, select the terminal device storing the PLMN information as the target device.

[0087] In a possible design, the selecting module is further configured to, when the available PLMN is the same as or different from the registered PLMN stored in each terminal device, select any one terminal device from the plurality of terminal devices as the target device, or select a master device from the plurality of terminal devices as the target device.

[0088] In a possible design, the selection module is further configured to select, as the target device, a first terminal device in the plurality of terminal devices when the available PLMN is the same as a registration PLMN stored by the first terminal device and different from registration PLMNs stored by other terminal devices in the plurality of terminal devices except the first terminal device.

[0089] In a possible design, the selection module is further configured to acquire, when the available PLMN is the same as or different from a registration PLMN stored by each terminal device, timestamp information of each terminal device in the plurality of terminal devices, the timestamp information including a time point at which the each terminal device last deregistered; and select the target device from the plurality of terminal devices according to the timestamp information.

[0090] In a possible design, the selection module is further configured to select, as the target device, a first terminal device in the plurality of terminal devices when timestamp information of the first terminal device is later than timestamp information of other terminal devices in the plurality of terminal devices except the first terminal device.

[0091] In a possible design, the selection module is further configured to acquire, when the available PLMN is the same as or different from a registration PLMN stored by each terminal device, timestamp information of each SIM card in the plurality of terminal devices and time length information of the each terminal device, the timestamp information including a time point at which the each terminal device last deregistered, and the time length information including a time length for which the network device maintains a security context of the each terminal device; and select the target device from the plurality of terminal devices according to the timestamp information and the time length information.

[0092] In a possible design, the selection module is further configured to subtract the timestamp information of the each terminal device from a current time point to calculate a first difference value corresponding to the each terminal device; subtract the first difference value corresponding to the each terminal device from the time length information of the each terminal device to calculate a second difference value corresponding to the each terminal device; and select, as the target device, a terminal device with a largest second difference value from the plurality of terminal devices.

[0093] The registration access apparatus performs the operations and has the advantages of the method in the second aspect, and details are not repeated here.

[0094] In a sixth aspect, an embodiment of the present application provides a registration access device, which has the function of the third aspect, for example, the registration access device includes a module or unit or means corresponding to the operation of the third aspect, which can be implemented by software, or by hardware, or by a combination of software and hardware. The device includes:

[0095] A searching module, configured to perform a public land mobile network (PLMN) selection to find available PLMNs.

[0096] A selecting module, configured to select a target device from the plurality of terminal devices according to the available PLMNs and PLMN information stored by the first terminal device.

[0097] A registering module, configured to initiate a registration access based on the stored security context of the target device.

[0098] In a possible design, the plurality of SIM cards included in the plurality of terminal devices belong to a same operator.

[0099] In a possible design, the PLMN information includes a registered PLMN.

[0100] In a possible design, the plurality of terminal devices are all in a de-registered state.

[0101] In a possible design, the searching module is further configured to perform the PLMN selection to find the available PLMNs based on a PLMN list, where the PLMN list includes at least one PLMN.

[0102] In a possible design, the searching module is further configured to select the available PLMNs from the PLMN list based on priorities of the PLMNs in the PLMN list.

[0103] In a possible design, the PLMN list includes at least one of the following PLMNs: a home public land mobile network (HPLMN), an equivalent home public land mobile network (EHPLMN), a user control public land mobile network (UPLMN), an operator control public land mobile network (OPLMN), or another PLMN.

[0104] In a possible design, the selecting module is further configured to select the first terminal device as the target device when the available PLMNs are the same as a registered PLMN stored by the first terminal device.

[0105] In a possible design, the selection module is further configured to: when the available PLMN is different from the registered PLMN stored by the first terminal device, acquire PLMN information stored by each of the terminal devices other than the first terminal device, to obtain the PLMN information stored by each of the terminal devices; and select the target device from the terminal devices according to the available PLMN and the PLMN information stored by each of the terminal devices.

[0106] In a possible design, the selection module is further configured to: when the registered PLMN stored by a second terminal device of the terminal devices is the same as the available PLMN, select the second terminal device as the target device.

[0107] In a possible design, the selection module is further configured to: when the registered PLMN stored by each of the terminal devices other than the first terminal device is different from the available PLMN, acquire timestamp information of each of the terminal devices, the timestamp information including a time point at which the terminal device last deregistered; and select the target device from the terminal devices according to the timestamp information.

[0108] In a possible design, the selection module is further configured to: if the timestamp information of a first terminal device of the terminal devices is later than that of a second terminal device, select the first terminal device as the target device; or if the timestamp information of the first terminal device is earlier than that of the second terminal device, select the second terminal device as the target device.

[0109] In a possible design, the selection module is further configured to: when the registered PLMN stored by each of the terminal devices other than the first terminal device is different from the available PLMN, acquire timestamp information and duration information of each of the terminal devices, the timestamp information including a time point at which the terminal device last deregistered, and the duration information including a duration for which the network device maintains a security context of the terminal device; and select the target device from the terminal devices according to the timestamp information and the duration information.

[0110] In a possible design, the selection module is further configured to: subtract the timestamp information of each of the terminal devices from a current time point to calculate a first difference value corresponding to the terminal device; subtract the first difference value corresponding to the terminal device from the duration information of the terminal device to calculate a second difference value corresponding to the terminal device; and select, as the target device, a terminal device with the largest second difference value from the terminal devices.

[0111] The registration module is further configured to, if a second terminal device is selected as the target device from the plurality of terminal devices, send first indication information, the first indication information being used to instruct the second terminal device to initiate registration access.

[0112] The operations and beneficial effects of the registration access apparatus can refer to the method and beneficial effects of the third aspect, and the repeated parts will not be described herein.

[0113] In a seventh aspect, an embodiment of the present application provides a registration access apparatus, which comprises a memory and one or more processors. The memory is configured to store part or all of the computer programs or instructions necessary for implementing the functions related to the first aspect to the third aspect. The one or more processors are configured to execute the computer programs or instructions, and when the computer programs or instructions are executed, the registration access apparatus implements the method in any possible design or implementation manner of the first aspect to the third aspect.

[0114] In a possible design, the registration access apparatus can further comprise an interface circuit, and the processor is configured to communicate with other apparatuses or components through the interface circuit.

[0115] In a possible design, the registration access apparatus can further comprise the memory.

[0116] The registration access apparatus can be a chip responsible for communication functions in the first device, such as a Modem chip (also known as a baseband chip) or a SoC or SIP chip containing a modem module.

[0117] In an eighth aspect, the present application provides a computer readable storage medium, which is configured to store a computer program. When the computer program is executed, the method in any one of the first aspect to the third aspect is implemented.

[0118] In a ninth aspect, the present application provides a computer program product comprising a computer program. When the computer program is executed, the method in any one of the first aspect to the third aspect is implemented.

[0119] In a tenth aspect, a chip is provided, which comprises a processor and a communication interface configured to communicate with external devices or internal devices, and the processor is configured to implement the method in each of the aspects.

[0120] In a possible design, the chip can further include a memory in which a computer program or instructions are stored, and the processor is configured to execute the computer program or instructions stored in the memory or other programs or instructions. When the computer program or instructions are executed, the processor is configured to implement the method in each of the aspects.

[0121] In a possible design, the chip can be integrated on the first device. BRIEF DESCRIPTION OF DRAWINGS

[0122] FIG. 1 is a schematic diagram of a communication system architecture;

[0123] FIG. 2 is a schematic diagram of a communication chip of a DualSteer device;

[0124] FIG. 3 is a schematic diagram of a structure of a bidirectional device;

[0125] FIG. 4 is a schematic diagram of a flow of a registration access method according to an embodiment of the present application;

[0126] FIG. 5 is a schematic diagram of a structure of an IMSI;

[0127] FIG. 6 is a schematic diagram of a flow of another registration access method according to an embodiment of the present application;

[0128] FIG. 7 is a schematic diagram of a structure of a first device;

[0129] FIG. 8 is a schematic diagram of a flow of yet another registration access method according to an embodiment of the present application;

[0130] FIG. 9 is a schematic diagram of a structure of a registration access apparatus according to an embodiment of the present application;

[0131] FIG. 10 is a schematic diagram of a structure of a first device according to an embodiment of the present application. DETAILED DESCRIPTION

[0132] The following explains main terms involved in the present application:

[0133] UPLMN: User Controlled PLMN Selector with Access Technology.

[0134] OPLMN: Operator Controlled PLMN Selector with Access Technology.

[0135] As shown in FIG. 1, FIG. 1 is a schematic diagram of a communication system architecture. The communication system is a third generation partnership project (3GPP) system architecture of the current fifth generation mobile communication technology (5th-generation, 5G). The communication system contains network functions and entities, mainly including: a terminal device (for example, a user equipment (UE)), a (wireless) access network (radio access network, (R)AN) device, a user plane function (UPF) network element, a data network (data network, DN) network element, an access and mobility management function (access and mobility management function, AMF) network element, a session management function (session management function, SMF) network element, a policy control function (policy control function, PCF) network element, an application function (application function, AF) network element, a network slice selection function (network slice selection function, NSSF) network element, an authentication server function (authentication server function, AUSF) network element, and a unified data management (unified data management, UDM) network element. The interaction relationship between the network functions and entities and the corresponding interfaces are shown in the figure, for example, the UE and the AMF network element can interact through the N1 interface, and the interaction message is called N1 Message. Some interfaces are implemented in the form of service interface.

[0136] The UE, the (R)AN device, the UPF network element, and the DN network element are generally referred to as data plane network functions and entities, and the data traffic of a user can be transmitted through a protocol data unit (PDU) session established between the UE and the DN network element, which passes through the (R)AN and the UPF network function entities. The other part is referred to as a control plane network function and entity, which is mainly responsible for authentication and authorization, registration management, session management, mobility management, and policy control functions, so as to realize the reliable and stable transmission of user layer traffic. The user plane is used for business data bearing, and the control plane is used for bearing signaling messages.

[0137] The functions of the main entities or network elements contained in the communication system are introduced as follows:

[0138] Terminal device: can be a UE, a handheld terminal, a notebook computer, a cellular phone, a smart phone, a tablet computer, a handheld device, an augmented reality (AR) device, a virtual reality (VR) device, a machine type communication terminal, or other devices that can access a network. The terminal device and the access network device communicate with each other using a certain air interface technology (such as new radio (NR) or long term evolution (LTE) technology). The terminal device and the terminal device can also communicate with each other using a certain air interface technology (such as NR or LTE technology). In vehicle-to-everything communication, the communication terminal uploaded by the vehicle is a terminal device, and the road side unit (RSU) can also be a terminal device. The unmanned aerial vehicle uploads a communication terminal and can be regarded as a terminal device.

[0139] RAN device: mainly responsible for wireless resource management, quality of service management, data compression and encryption and other functions on the air interface side. The access network device can include various forms of base stations, such as macro base stations, micro base stations, relay stations, access points, etc. In systems using different wireless access technologies, the names of devices with base station functions may be different, for example, in a 5G system, it is called gNB.

[0140] AMF network element: belongs to the core network element, 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 the terminal device, it provides storage resources for the control plane of the session to store session identifiers, SMF network element identifiers associated with session identifiers, etc.

[0141] SMF network element: 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.

[0142] UPF network element: responsible for forwarding and receiving user data in the terminal device. It can receive user data from a data network and transmit it to the terminal device through the access network device; the UPF network element can also receive user data from the terminal device through the access network device and forward it to the data network. The transmission resources and scheduling functions provided by the UPF network element for the terminal device are managed and controlled by the SMF network element.

[0143] NEF network element: mainly supports the interaction between 3GPP networks and third-party applications for security.

[0144] AF network element: mainly supports interaction with the 3GPP core network to provide services, such as affecting data routing decisions, policy control functions, or providing some services of third parties to the network side.

[0145] PCF network element: responsible for policy control decision, providing policy rules of control plane function, and traffic-based charging control function.

[0146] NSSF network element: mainly responsible for network slice selection, determining the network slice instance that the UE is allowed to access according to the slice selection assistance information, subscription information, etc. of the UE.

[0147] UDM network element: mainly responsible for the management of UE subscription data, including the storage and management of UE identity, access authorization of UE, etc.

[0148] AUSF network element: supports 3GPP and non-3GPP access authentication.

[0149] NRF network element: supports registration and discovery of network functions.

[0150] UDR network element: stores and obtains subscription data used by UDM and PCF.

[0151] NWDAF network element: supports data collection from other network functions and AFs; supports data collection from operation administration and maintenance (OAM); supports providing analysis information to other network functions, AFs.

[0152] The technical solutions in the embodiments of the present application can be applied to various communication systems, such as universal mobile communication system (UMTS), wireless local area network (WLAN), wireless fidelity (Wi-Fi) system, 4th generation (4G) mobile communication system such as long term evolution (LTE) system, 5th generation (5G) mobile communication system such as new radio (NR) system, and future evolved communication system such as 6th generation (6G) mobile communication system, etc.

[0153] Embodiments of the present application are mainly applied to DualSteer devices. As shown in FIG. 2, FIG. 2 is a schematic diagram of a communication chip of a DualSteer device. The communication chip mainly consists of a baseband subsystem, a radio frequency subsystem, a power management subsystem, peripherals (storage, external interface), and the like. Functions of each part are as follows:

[0154] The baseband subsystem is responsible for application layer processing, external interface, and the like, and L3 / L2 / L1 communication protocol processing.

[0155] The radio frequency subsystem is responsible for conversion of spatial electromagnetic waves to electrical signals, amplification, filtering, and the like, and achieves excellent coverage targets; and is connected with the baseband to complete frequency conversion and non-linear distortion correction of analog signals.

[0156] The power management subsystem provides power management functions for the communication baseband chip.

[0157] As shown in FIG. 3, FIG. 3 is a structural schematic diagram of a bidirectional device. The DS device can include one UE or dual UEs. For a single UE, the UE includes two different USIMs, and the USIM corresponds to a subscription permanent identifier (SUPI). The UE can be connected to each 3GPP access network through each SIM card. For dual UEs, each UE is connected to a separate 3GPP access network as part of the DualSteer.

[0158] Currently, selection of the UE or the SIM card is based on a configuration manner, in which a specific UE is configured as a primary UE, or a specific SIM card is configured as a primary SIM card. When it is necessary to select the UE or the SIM card to initiate registration access, the primary UE or the primary SIM card is selected, and then PLMN selection is performed based on the selected UE or the selected SIM card. If the UE or the SIM card is selected first, and then the PLMN selection is performed based on the selected UE or the selected SIM card, the following two cases can exist:

[0159] The first case is that the available PLMN is different from the registration PLMN stored in the SIM card, wherein the PLMN information stored in the SIM card is a PLMN associated with a security context. If there is no interface between mobile management network elements of the two PLMNs, the initiated registration process can fail, or needs to be re-authenticated, resulting in registration delay and increased signaling overhead. Alternatively, if there is an interface between the mobile management network elements of the two PLMNs, the security context also needs to be obtained from the mobile management network element of the previous PLMN, also resulting in registration delay and increased signaling overhead.

[0160] The second case: the available PLMN is the same as the registration PLMN stored in the SIM card, but the security context stored in the network side has been deleted due to time limit, which also causes unsuccessful registration and registration delay, and increases signaling overhead.

[0161] To solve the above technical problems, the embodiments of the present application provide the following solutions.

[0162] As shown in FIG. 4, FIG. 4 is a flow diagram of a registration access method provided by the embodiments of the present application. The embodiments of the present application are applicable to the scenario that the first device (for example, a DS device) contains a dual-SIM card (that is, a single UE dual-SIM card) and are executed by the first device. The method mainly includes the following steps:

[0163] S401, the first device performs PLMN selection to find an available PLMN.

[0164] The first device is in a de-registered state on each of the plurality of SIM cards, that is, the first device is in a de-registered state when using any one of the plurality of SIMs.

[0165] Specifically, the first device can perform PLMN selection to find the available PLMN based on a PLMN list, and the PLMN list includes at least one PLMN. The PLMN list is stored in the NV of the first device or a SIM card, and the first device can read the PLMN list from the NV or the SIM card of itself. Further, the first device can select the available PLMN from the PLMN list based on the priority of each PLMN in the PLMN list. For example, the PLMN with the highest priority is selected.

[0166] The PLMN list can include at least one of the following PLMNs: a home public land mobile network (HPLMN), an equivalent home public land mobile network (EHPLMN), a UPLMN, an OPLMN, or other PLMNs.

[0167] The following introduces several PLMNs.

[0168] (1) HPLMN is derived from international mobile subscriber identity (IMSI) (first 5 digits or 6 digits), as shown in FIG. 5, which is a structure diagram of IMSI. IMSI can include mobile country code (MCC), mobile network code (MNC) and mobile subscriber identification number (MSIN). Among them, MCC includes 3 digits, MNC includes 2 or 3 digits, and IMSI is at most 15 digits. IMSI is stored in a SIM card, and IMSI is used to identify different SIM cards or users. The two SIM cards contained by the first device should be configured with IMSI. For the first device, the HPLMNs of the two SIM cards are the same, so the HPLMN can be obtained by reading any one SIM card. In the absence of EHPLMN configuration, HPLMN has the highest priority in selecting PLMN.

[0169] (2) EHPLMN is stored in a SIM card. For the first device, the two SIM cards are issued by the same operator, so the EHPLMNs are the same. It is possible that the EHPLMN is configured on both SIM cards, or the EHPLMN is configured only on one SIM card (such as the main SIM card). If the EHPLMN is configured on both SIM cards, the EHPLMNs on the two SIM cards are the same, and the EHPLMN can be obtained by reading any one SIM card. If the EHPLMN is configured only on one SIM card, the EHPLMN can be obtained by reading the SIM card. In selecting PLMN, EHPLMN has the highest priority.

[0170] (3) UPLMN is the PLMN configured for the user, which is the PLMN that the user wants to use, and is generally stored in the SIM card or non-volatile (NV) of the UE. For Single-UE case (single-UE dual card), the first device only has one set of UPLMN information. UPLMN has a lower priority than HPLMN or EHPLMN.

[0171] (4) OPLMN is a network-recommended PLMN, which can also be stored in the SIM card or NV of the UE, and can be pre-configured in the SIM card on the network side, and can also be updated to the UE by the network side later. It is possible that both SIM cards are configured with OPLMN, or only one SIM card (such as the main SIM card) is configured with OPLMN. If OPLMN is configured on both SIM cards, the OPLMN of the two SIM cards is the same, and the OPLMN can be obtained by reading any one SIM card. If only one SIM card is configured with OPLMN, the OPLMN can be obtained by reading the SIM card. The priority of OPLMN is lower than that of UPLMN, HPLMN or EHPLMN.

[0172] Optionally, the first device can find available PLMNs in performing the cell selection process. Alternatively, the first device can also find available PLMNs in performing the PLMN selection and cell selection processes. Optionally, the found available PLMNs are the highest priority PLMNs existing in the surrounding environment. The PLMN selection can include PLMN automatic selection and PLMN manual selection.

[0173] Optionally, the first device can obtain PLMN information stored by each SIM card of the plurality of SIM cards. Optionally, the PLMN information can also be stored in the NV but is associated with the SIM card.

[0174] Among them, the plurality of SIM cards belong to the same operator, which can be understood as that the plurality of SIM cards are issued by the same operator, for example, the plurality of SIM cards are all SIM cards issued by China Mobile. The PLMN information includes a registered PLMN (RPLMN), which is the last registered PLMN, and the security context stored by the SIM card is negotiated by the UE and the PLMN.

[0175] Specifically, the first device can obtain the PLMN information by reading the Last visited registered tracking area identity (TAI) in 5GS from 5G system (5G system, 5GS) 3GPP location information or 5GS non-3GPP location information. The composition of TAI is as follows: MCC+MNC+TAC (tracking area code, tracking area code), and the MCC+MNC part is the PLMN.

[0176] S402, the first device selects a target SIM card from the plurality of SIM cards according to the available PLMNs and the PLMN information stored by each SIM card of the plurality of SIM cards.

[0177] In an implementation, when only one SIM card in the plurality of SIM cards stores the PLMN information, the SIM card storing the PLMN information is selected as the target SIM card.

[0178] In another implementation, the target SIM card can be selected from the plurality of SIM cards according to the available PLMN and the PLMN information stored by each SIM card. Further, the following cases are specifically included:

[0179] When the available PLMN is the same as or different from the registered PLMN stored by each SIM card, a SIM card can be selected from the plurality of SIM cards as the target SIM card, or a primary SIM card (or a SIM card with a tendency) can be selected from the plurality of SIM cards as the target SIM card. Alternatively, when the available PLMN is the same as the registered PLMN stored by a first SIM card in the plurality of SIM cards and different from the registered PLMN stored by other SIM cards in the plurality of SIM cards except the first SIM card, the first SIM card is selected from the plurality of SIM cards as the target SIM card.

[0180] The above only refers to the available PLMN and the PLMN information stored by each SIM card. When selecting the SIM card, the first device can also refer to time information, which can include timestamp information and duration information. The timestamp information includes a time point of a last time when each SIM card is deregistered. When a SIM card is deregistered, the first device needs to write the security context of the SIM card into an NV or a corresponding SIM card, and record the time point (timestamp information) of the deregistration of the SIM card in the NV or the corresponding SIM card. The duration information includes a duration of maintaining the security context by the network side. The duration information can be delivered to the first device by the network. The core network (CN) can update the duration information of the SIM card through a NAS message. The NAS message can include a registration accept message or a configuration update command (CUC) message.

[0181] In another implementation, the target SIM card can be selected from the plurality of SIM cards according to the available PLMN, the PLMN information stored by each SIM card and the time information. Further, the following cases are specifically included:

[0182] When the available PLMN is the same as or different from the registered PLMN stored by each SIM card, timestamp information of each SIM card in the plurality of SIM cards is acquired, and the target SIM card is selected from the plurality of SIM cards according to the timestamp information. Further, if the timestamp information of a first SIM card in the plurality of SIM cards is later than the timestamp information of a second SIM card, the first SIM card is selected as the target SIM card; if the timestamp information of the first SIM card is earlier than the timestamp information of the second SIM card, the second SIM card is selected as the target SIM card. By selecting the SIM card that is registered later last time to initiate registration, the security context of the SIM card is prevented from being deleted due to time limit, the success rate of registration is improved, re-authentication or obtaining the security context from the mobile management network element of the previous PLMN is avoided, the registration efficiency is improved, and the signaling overhead is reduced.

[0183] When the available PLMN is the same as or different from the registered PLMN stored by each SIM card, timestamp information and duration information of each SIM card in the plurality of SIM cards are acquired, and the target SIM card is selected from the plurality of SIM cards according to the timestamp information and the duration information. Further, a first difference value corresponding to each SIM card can be calculated by subtracting the timestamp information of each SIM card from the current time point; a second difference value corresponding to each SIM card can be calculated by subtracting the first difference value corresponding to each SIM card from the duration information of each SIM card; and the SIM card with the largest second difference value is selected as the target SIM card from the plurality of SIM cards. For example, the SIM card with a larger value of (duration information - (current time point - timestamp information)) can be selected. By selecting the SIM card that maintains the security context for a longer time and is registered later last time to initiate registration, the security context of the SIM card is prevented from being deleted due to time limit, the success rate of registration is improved, re-authentication or obtaining the security context from the mobile management network element of the previous PLMN is avoided, the registration efficiency is improved, and the signaling overhead is reduced.

[0184] It should be noted that, if the available PLMN is the same as the registered PLMN stored by a first SIM card in the plurality of SIM cards and different from the registered PLMN stored by other SIM cards in the plurality of SIM cards except the first SIM card, the first SIM card can be selected as the target SIM card without referring to the time information to select the target SIM card, that is, when the PLMN of one of the two SIM cards is the same as the available PLMN, the one SIM card with the same available PLMN is directly selected as the target SIM card.

[0185] S403, the first device initiates registration access based on the security context stored by the target SIM card, such as initial registration.

[0186] The security context can include a NAS key set identifier (ngKSI), a NAS integrity and encryption algorithm, and the like. Alternatively, the security context can also be stored in the NV but associated with the target SIM card, and the first device initiates the registration access based on the security context associated with the current SIM card.

[0187] In the embodiments of the present application, in the scenario where the first device contains dual SIM cards, one of the SIM cards is selected by searching for the available PLMN and the PLMN information stored by each SIM card, and then the security context of the selected SIM card is used to initiate the registration, so as to avoid the failure of the registration process caused by the difference between the available PLMN and the registration PLMN stored by the SIM card, improve the success rate of the registration, avoid re-authentication and authentication or obtaining the security context from the mobility management network element of the previous PLMN, improve the registration efficiency, and reduce the signaling overhead.

[0188] As shown in FIG. 6, FIG. 6 is a flowchart of another registration access method provided by the embodiments of the present application. The embodiments of the present application are applicable to the scenario where the first device (for example, a DS device) contains dual UE (that is, dual UE single SIM card). The method is performed by the first device, and mainly includes the following steps:

[0189] S601, the first device acquires the available PLMN searched by the PLMN selection.

[0190] Specifically, the first device can select the first terminal device from a plurality of terminal devices, the first terminal device searches for the available PLMN by performing the PLMN selection, and the first device acquires the available PLMN searched by the first terminal device. Alternatively, the first terminal device can also search for the available PLMN by performing the cell selection process. Alternatively, the first terminal device can also search for the available PLMN by performing the PLMN selection and the cell selection process. Alternatively, the searched available PLMN is the highest priority PLMN existing in the surrounding environment. The PLMN selection can include PLMN automatic selection and PLMN manual selection. The plurality of terminal devices in the first device are all in the deregistered state.

[0191] Further, the first device can select any one of the plurality of terminal devices, or select one of the plurality of terminal devices according to a pre-configured strategy, for example, select a master device, and perform the PLMN selection and cell selection process through the selected terminal device. In this process, the DS layer in the first device can determine which terminal device to select. As shown in FIG. 7, which is a structural diagram of a first device. The first device includes UE1, UE2, and a DS layer, and the first device can select UE1 or UE2 through the DS layer. Then UE1 or UE2 searches for available PLMNs, and if UE1 or UE2 finds an available PLMN, UE1 or UE2 provides the available PLMN to the DS device.

[0192] Optionally, the first terminal device can select the available PLMN from a PLMN list, the PLMN list including at least one PLMN. The PLMN list is stored in the NV or SIM card of each terminal device, and the first terminal device can read the PLMN list from the NV or SIM card of itself.

[0193] Further, the first terminal device can select the available PLMN from the PLMN list based on the priority of each PLMN in the PLMN list. For example, select the PLMN with the highest priority. The PLMN list can include at least one of the following PLMNs: HPLMN, EHPLMN, UPLMN, OPLMN, or other PLMNs. The selection method of the PLMN in this embodiment is the same as that in the previous embodiment S401, and the specific implementation method can refer to the steps of the previous embodiment S401, which will not be described here.

[0194] Optionally, the first device can obtain the PLMN information stored by each terminal device of the plurality of terminal devices.

[0195] Specifically, the first device can read the PLMN information stored in the SIM card or NV of each terminal device. Further, the first device can obtain the PLMN information by reading the Last visited registered tracking area identity in 5GS from the 5GS 3GPP location information or 5GS non-3GPP location information. The composition of TAI is as follows: MCC+MNC+TAC, and the MCC+MNC part is the PLMN.

[0196] The PLMN information includes a registered PLMN (RPLMN), which is the last registered PLMN. The plurality of SIM cards included in the plurality of terminal devices (one terminal device includes one SIM card) belong to the same operator, which can be understood as: the plurality of SIM cards of the plurality of terminal devices are issued by the same operator, for example, the plurality of SIM cards are all SIM cards issued by China Mobile.

[0197] In S602, the first device selects a target device from the plurality of terminal devices according to the available PLMN and the PLMN information stored by each terminal device.

[0198] In an implementation, when only one terminal device in the plurality of terminal devices stores the PLMN information, the terminal device storing the PLMN information is selected as the target device.

[0199] In another implementation, the target device can be selected from the plurality of terminal devices according to the available PLMN and the PLMN information stored by each terminal device. Further, the following cases are specifically included:

[0200] When the available PLMN is the same as or different from the registered PLMN stored by each terminal device, a terminal device is randomly selected from the plurality of terminal devices as the target device, or a master device (or a terminal device with a tendency) is selected from the plurality of terminal devices as the target device. Alternatively, when the available PLMN is the same as the registered PLMN stored by a first terminal device in the plurality of terminal devices and different from the registered PLMN stored by other terminal devices in the plurality of terminal devices except the first terminal device, the first terminal device is selected as the target device.

[0201] The above only refers to the available PLMN and the PLMN information stored by each terminal device. When selecting the target device, the first device can also refer to time information. The time information can include timestamp information and duration information. The timestamp information includes a time point at which each terminal device was last deregistered. When a terminal device is deregistered, the first device needs to write the security context of the terminal device into an NV or a corresponding SIM card, and record the time point (timestamp information) at which the terminal device is deregistered in the NV or the corresponding SIM card. The duration information includes a duration for which the network side maintains the security context. The duration information can be sent to the first device by the network. The core network (CN) can update the duration information of the terminal device through a NAS message. The NAS message can include a registration accept message or a configuration update command (CUC) message.

[0202] In another implementation, the target device can be selected from the plurality of terminal devices according to the available PLMN, the PLMN information stored by each terminal device and time information. Further, the following cases are included:

[0203] When the available PLMN is the same as or different from the registered PLMN stored by each terminal device, the time stamp information of each terminal device is obtained, and the target device is selected from the plurality of terminal devices according to the time stamp information. Further, if the time stamp information of a first terminal device is later than that of a second terminal device, the first terminal device is selected as the target device; if the time stamp information of the first terminal device is earlier than that of the second terminal device, the second terminal device is selected as the target device. By selecting the terminal device that has not been deregistered for a longer time to initiate registration, the security context of the terminal device is prevented from being deleted due to time limitation, the success rate of registration is improved, re-authentication or obtaining of the security context from the mobility management network element of the previous PLMN is avoided, the registration efficiency is improved, and the signaling overhead is reduced.

[0204] When the available PLMN is the same as or different from the registered PLMN stored by each terminal device, the time stamp information and the time length information of each terminal device are obtained, and the target device is selected from the plurality of terminal devices according to the time stamp information and the time length information. Further, the first difference value corresponding to each terminal device can be calculated by subtracting the time stamp information of each terminal device from the current time point; the second difference value corresponding to each terminal device can be calculated by subtracting the first difference value corresponding to each terminal device from the time length information of each terminal device; and the terminal device with the largest second difference value is selected as the target device from the plurality of terminal devices. For example, the terminal device with a larger value of (time length information - (current time point - time stamp information)) can be selected. By selecting the terminal device that has maintained the security context for a longer time and has not been deregistered for a longer time to initiate registration, the security context of the terminal device is prevented from being deleted due to time limitation, the success rate of registration is improved, re-authentication or obtaining of the security context from the mobility management network element of the previous PLMN is avoided, the registration efficiency is improved, and the signaling overhead is reduced.

[0205] It should be noted that if the available PLMN is the same as the registration PLMN stored by a first terminal device of the plurality of terminal devices, and is different from the registration PLMN stored by other terminal devices of the plurality of terminal devices except the first terminal device, the first terminal device can be selected as the target device without referring to the time information to select the target device, that is, if the PLMN information stored by one of the two terminal devices is the same as the available PLMN, the one terminal device with the same available PLMN is directly selected as the target device.

[0206] In S603, the first device initiates registration access based on the security context stored by the target device, such as initial registration.

[0207] In the embodiments of the present application, the first device selects one of the terminal devices through the available PLMN and the PLMN information stored by each terminal device, and then initiates registration through the security context of the selected terminal device, so as to avoid the failure of the registration process caused by the difference between the available PLMN and the registration PLMN stored by the terminal device, improve the success rate of registration, avoid re-authentication and authentication or obtaining the security context from the mobility management network element of the previous PLMN, improve the registration efficiency, and reduce the signaling overhead.

[0208] As shown in FIG. 8, FIG. 8 is a flowchart of another registration access method provided by the embodiments of the present application. The embodiments of the present application are applicable to the scenario in which the first device (for example, the DS device) contains dual UE (that is, dual UE single SIM card). The method is performed by the first terminal device in the first device, and mainly includes the following steps:

[0209] In S801, the first terminal device performs PLMN selection to find the available PLMN.

[0210] Specifically, the first terminal device can perform PLMN selection to find the available PLMN based on a PLMN list, and the PLMN list includes at least one PLMN. The PLMN list is stored in the NV or SIM card of each terminal device, and the first terminal device can read the PLMN list from the NV or SIM card of itself.

[0211] Further, the first terminal device can select the available PLMN from the PLMN list based on the priority of each PLMN in the PLMN list. For example, the PLMN with the highest priority is selected. The PLMN list can include at least one of the following PLMNs: HPLMN, EHPLMN, UPLMN, OPLMN, or other PLMNs. The selection manner of the PLMN in the embodiments of the present application is the same as the selection manner of the PLMN in the previous embodiment S401, and the specific implementation manner can refer to the steps of the previous embodiment S401, which will not be described here.

[0212] Optionally, the first terminal device can find the available PLMN by performing a cell selection procedure. Alternatively, the first terminal device can find the available PLMN by performing a PLMN selection procedure and a cell selection procedure. Optionally, the found available PLMN is the highest priority PLMN in the surrounding environment. The PLMN selection can include a PLMN automatic selection and a PLMN manual selection.

[0213] Optionally, the first device can select the first terminal device from the plurality of terminal devices, and then the first terminal device performs the PLMN selection to find the available PLMN. Further, the first device can select any one of the plurality of terminal devices, or select one of the plurality of terminal devices according to a pre-configured strategy, for example, select a master device. In this process, the DS layer in the first device can determine which terminal device to select.

[0214] Optionally, the plurality of terminal devices in the first device are in a de-registered state. The plurality of SIM cards (one terminal device contains one SIM card) contained in the plurality of terminal devices belong to the same operator. It can be understood that the plurality of SIM cards of the plurality of terminal devices are issued by the same operator, for example, the plurality of SIM cards are all SIM cards issued by China Mobile.

[0215] Optionally, the first terminal device can obtain the PLMN information stored by the first terminal device. For example, the first terminal device can read the PLMN information stored in the NV or the SIM card of the first terminal device.

[0216] Optionally, the first terminal device can obtain the PLMN information stored by the first terminal device. For example, the first terminal device can read the PLMN information stored in the NV or the SIM card of the first terminal device.

[0217] Optionally, the first terminal device can obtain the PLMN information stored by the first terminal device. For example, the first terminal device can read the PLMN information stored in the NV or the SIM card of the first terminal device.

[0218] S802, the first terminal device selects a target device from the plurality of terminal devices according to the available PLMN and the PLMN information stored by the first terminal device.

[0219] Specifically, when the available PLMN is the same as the registration PLMN stored in the first terminal device, the first terminal device is selected as the target device. That is, if the first terminal device determines that the available PLMN is the same as the registration PLMN stored in the first terminal device, the first terminal device directly initiates the registration access without querying the PLMN information stored in another terminal device, thereby avoiding querying the PLMN information stored in other terminal devices and improving the registration efficiency.

[0220] Optionally, when only the first terminal device stores the PLMN information in the plurality of terminal devices, the first terminal device is selected as the target device.

[0221] Optionally, when the available PLMN is different from the registration PLMN stored in the first terminal device, the PLMN information stored in the terminal devices other than the first terminal device in the plurality of terminal devices is acquired, the PLMN information stored in each terminal device in the plurality of terminal devices is obtained, and the target device is selected from the plurality of terminal devices according to the available PLMN and the PLMN information stored in each terminal device in the plurality of terminal devices. Specifically, the following implementation manners can be included:

[0222] In a first implementation manner, when the registration PLMN stored in a second terminal device in the plurality of terminal devices is the same as the available PLMN, the second terminal device is selected as the target device. That is, if the first terminal device determines that the available PLMN is different from the registration PLMN stored in the first terminal device and the available PLMN is the same as the registration PLMN stored in the second terminal device, the second terminal device is selected, and the registration access is directly initiated through the security context stored in the second terminal device, thereby further improving the registration efficiency.

[0223] In a second implementation manner, when the registration PLMN stored in the terminal devices other than the first terminal device in the plurality of terminal devices is different from the available PLMN, the timestamp information of each terminal device in the plurality of terminal devices is acquired, the timestamp information including a time point at which the each terminal device last deregisters, and the target device is selected from the plurality of terminal devices according to the timestamp information. That is, if the first terminal device determines that the available PLMN is different from the registration PLMN stored in the first terminal device and the available PLMN is also different from the registration PLMN stored in the second terminal device, the target device is selected according to the timestamp information of each terminal device.

[0224] Further, if the timestamp information of a first terminal device in the plurality of terminal devices is later than the timestamp information of a second terminal device, the first terminal device is selected as the target device; if the timestamp information of the first terminal device in the plurality of terminal devices is earlier than the timestamp information of the second terminal device, the second terminal device is selected as the target device. By selecting the terminal device that has been deregistered later to initiate registration, the security context of the terminal device that is limited by time is avoided from being deleted, the success rate of registration is improved, re-authentication or obtaining the security context from the mobility management network element of the previous PLMN is avoided, the registration efficiency is improved, and the signaling overhead is reduced.

[0225] In a third implementation, when the registered PLMN stored by a terminal device other than the first terminal device in the plurality of terminal devices is different from the available PLMN, the timestamp information and the time length information of each terminal device in the plurality of terminal devices are obtained, the timestamp information includes a time point at which the each terminal device is last deregistered, and the time length information includes a time length for which the network device maintains the security context of the each terminal device, wherein the time length information is network-downloaded to the first terminal device; and the target device is selected from the plurality of terminal devices according to the timestamp information and the time length information. That is, if the first terminal device determines that the available PLMN is different from the registered PLMN stored in the first terminal device, and the available PLMN is also different from the registered PLMN stored in the second terminal device, the target device is selected according to the timestamp information and the time length information of each terminal device.

[0226] Further, a first difference value corresponding to the each terminal device is calculated by subtracting the timestamp information of the each terminal device from a current time point; a second difference value corresponding to the each terminal device is calculated by subtracting the first difference value corresponding to the each terminal device from the time length information of the each terminal device; and the terminal device with the largest second difference value is selected as the target device from the plurality of terminal devices. For example, the terminal device with a larger value of (time length information - (current time point - timestamp information)) can be selected. By selecting the terminal device that has been deregistered later to initiate registration, the security context of the terminal device that is limited by time is avoided from being deleted, the success rate of registration is improved, re-authentication or obtaining the security context from the mobility management network element of the previous PLMN is avoided, the registration efficiency is improved, and the signaling overhead is reduced.

[0227] Optionally, if a second terminal device is selected as the target device from the plurality of terminal devices, the first terminal device sends first indication information, the first indication information being used to instruct the second terminal device to initiate the registration access. Further, the first terminal device can directly send the first indication information to the second terminal device, or the first terminal device can send the first indication information to the first device, and instruct the second terminal device to initiate the registration access through the first device.

[0228] S803. The target device initiates the registration access based on the security context stored by the target device, such as initial registration.

[0229] Specifically, when the first terminal device is selected as the target device, the first terminal device initiates the registration access based on the security context stored by the first terminal device, and when the second terminal device is selected as the target device, the second terminal device initiates the registration access based on the security context stored by the second terminal device.

[0230] In the embodiments of the present application, the first terminal device selects one of the terminal devices through the available PLMN and the PLMN information stored by the first terminal device, and initiates the registration through the security context of the selected terminal device, thereby avoiding the failure of the registration process caused by the difference between the available PLMN and the registration PLMN stored by the terminal device, improving the success rate of the registration, avoiding the re-authentication and the acquisition of the security context from the mobility management network element of the previous PLMN, improving the registration efficiency, and reducing the signaling overhead.

[0231] It can be understood that the methods and operations implemented by the first device or the first terminal device in the first device in each of the above method embodiments can also be implemented by components (such as chips or circuits) that can be used for the first device or the first terminal device in the first device.

[0232] The embodiments of the present application can divide the functional modules of the first device or the first terminal device in the first device according to the above method examples, for example, each functional module can be divided according to each function, or two or more functions can be integrated in one processing module. The above integrated module can be implemented in the form of hardware or in the form of a software functional module. It should be noted that the division of the modules in the embodiments of the present application is illustrative, and is only a logical function division. When actually implemented, another division mode can be used. The following will be described by taking the division of each functional module corresponding to each function as an example.

[0233] The method provided by the embodiments of the present application is described in detail above in combination with FIG. 4, FIG. 6 and FIG. 8. The registration access apparatus provided by the embodiments of the present application is described in detail below in combination with FIG. 9. It should be understood that the description of the apparatus embodiments corresponds to the description of the method embodiments, and therefore, the content not described in detail can be referred to the method embodiments described above, which will not be described here again for the sake of brevity.

[0234] Referring to FIG. 9, FIG. 9 is a structural schematic diagram of a registration access apparatus provided by the embodiments of the present application. The registration access apparatus can implement the steps or processes performed by the terminal device corresponding to the method embodiments described above. In a possible design, the registration access apparatus can include a searching module 901, a selecting module 902 and a registering module 903. Optionally, the registration access apparatus can further include a storage module for storing apparatus program codes and / or data.

[0235] The registration access apparatus can be a terminal-side apparatus in the embodiments described above, for example, a communication module in the first device or a circuit or chip responsible for communication function in the first device, or a first terminal device in the first device or a communication module of the first terminal device in the first device, or a circuit or chip responsible for communication function in the first terminal device in the first device.

[0236] In one embodiment,

[0237] The searching module 901 is configured to perform public land mobile network (PLMN) selection to find available PLMNs.

[0238] The selecting module 902 is configured to select a target SIM card from the plurality of SIM cards according to the available PLMNs and the PLMN information stored in each of the plurality of SIM cards.

[0239] The registering module 903 is configured to initiate registration access based on the security context stored in the target SIM card.

[0240] Optionally, the plurality of SIM cards belong to the same operator.

[0241] Optionally, the PLMN information includes a registered PLMN.

[0242] Optionally, the first device is in a de-registered state on the plurality of SIM cards.

[0243] Optionally, the searching module 901 is further configured to perform PLMN selection to find the available PLMNs based on a PLMN list, and the PLMN list includes at least one PLMN.

[0244] Optionally, the searching module 901 is further configured to search the available PLMN from the PLMN list based on priorities of each PLMN in the PLMN list.

[0245] Optionally, the PLMN list comprises at least one of the following PLMNs: a home public land mobile network (HPLMN), an equivalent home public land mobile network (EHPLMN), a user control public land mobile network (UPLMN), an operator control public land mobile network (OPLMN), or other PLMNs.

[0246] Optionally, the selecting module 902 is further configured to select a SIM card storing PLMN information as the target SIM card when only one SIM card in the plurality of SIM cards stores PLMN information.

[0247] Optionally, the selecting module 902 is further configured to select a SIM card from the plurality of SIM cards as the target SIM card when the available PLMN is the same as or different from the registration PLMN stored by each SIM card.

[0248] Optionally, the selecting module 902 is further configured to select a first SIM card from the plurality of SIM cards as the target SIM card when the available PLMN is the same as the registration PLMN stored by the first SIM card and different from the registration PLMN stored by other SIM cards except the first SIM card.

[0249] Optionally, the selecting module 902 is further configured to acquire timestamp information of each SIM card in the plurality of SIM cards when the available PLMN is the same as or different from the registration PLMN stored by each SIM card, the timestamp information comprising a time point of last de-registration of each SIM card; and select the target SIM card from the plurality of SIM cards according to the timestamp information.

[0250] Optionally, the selecting module 902 is further configured to select a first SIM card from the plurality of SIM cards as the target SIM card when the timestamp information of the first SIM card is later than the timestamp information of other SIM cards except the first SIM card.

[0251] Optionally, the selection module 902 is further configured to: when the available PLMN is the same as or different from the registration PLMN stored by each SIM card, acquire timestamp information and time length information of each SIM card in the plurality of SIM cards, the timestamp information comprising a time point of last de-registration of each SIM card, and the time length information comprising a time length for which the network device maintains a security context corresponding to each SIM card; and select the target SIM card from the plurality of SIM cards according to the timestamp information and the time length information.

[0252] Optionally, the selection module 902 is further configured to: subtract the timestamp information of each SIM card from a current time point to obtain a first difference value corresponding to each SIM card; subtract the first difference value corresponding to each SIM card from the time length information of each SIM card to obtain a second difference value corresponding to each SIM card; and select a SIM card with the largest second difference value from the plurality of SIM cards as the target SIM card.

[0253] In another embodiment,

[0254] The search module 901 is configured to acquire an available PLMN for performing a public land mobile network (PLMN) selection search.

[0255] The selection module 902 is configured to select a target device from the plurality of terminal devices according to the available PLMN and PLMN information stored by each terminal device in the plurality of terminal devices.

[0256] The registration module 903 is configured to initiate a registration access based on a security context stored by the target device.

[0257] Optionally, the plurality of SIM cards included in the plurality of terminal devices belong to a same operator.

[0258] Optionally, the PLMN information comprises a registration PLMN.

[0259] Optionally, the plurality of terminal devices are in a de-registered state.

[0260] Optionally, the available PLMN is selected from a PLMN list, and the PLMN list comprises at least one PLMN.

[0261] Optionally, the available PLMN is selected based on a priority of each PLMN in the PLMN list.

[0262] Optionally, the PLMN list comprises at least one of the following PLMNs: a home public land mobile network (HPLMN), an equivalent home public land mobile network (EHPLMN), a user-controlled public land mobile network (UPLMN), an operator-controlled public land mobile network (OPLMN), or other PLMNs.

[0263] Optionally, the searching module 901 is further configured to select a first terminal device from the plurality of terminal devices, and acquire the available PLMNs for which the first terminal device performs public land mobile network (PLMN) selection searching.

[0264] Optionally, the selecting module 902 is further configured to, when only one terminal device of the plurality of terminal devices stores PLMN information, select the terminal device storing the PLMN information as the target device.

[0265] Optionally, the selecting module 902 is further configured to, when the available PLMNs are all the same as or all different from the registered PLMNs stored by each terminal device, select a terminal device from the plurality of terminal devices as the target device, or select a master device from the plurality of terminal devices as the target device.

[0266] Optionally, the selecting module 902 is further configured to, when the available PLMNs are the same as the registered PLMNs stored by a first terminal device of the plurality of terminal devices and different from the registered PLMNs stored by other terminal devices of the plurality of terminal devices except the first terminal device, select the first terminal device as the target device.

[0267] Optionally, the selecting module 902 is further configured to, when the available PLMNs are all the same as or all different from the registered PLMNs stored by each terminal device, acquire time stamp information of each terminal device of the plurality of terminal devices, the time stamp information comprising a time point at which the each terminal device last deregistered, and select the target device from the plurality of terminal devices according to the time stamp information.

[0268] Optionally, the selecting module 902 is further configured to, if the time stamp information of a first terminal device of the plurality of terminal devices is later than the time stamp information of other terminal devices except the first terminal device, select the first terminal device as the target device.

[0269] Optionally, the selecting module 902 is further configured to: when the available PLMN is the same as or different from the registered PLMN stored by each terminal device, acquire timestamp information and time length information of each SIM card in the plurality of terminal devices, the timestamp information comprising a time point at which each terminal device was last deregistered, and the time length information comprising a time length for which the network device maintains a security context of each terminal device; and select the target device from the plurality of terminal devices according to the timestamp information and the time length information.

[0270] Optionally, the selecting module 902 is further configured to: subtract the timestamp information of each terminal device from a current time point to obtain a first difference value corresponding to each terminal device; subtract the first difference value corresponding to each terminal device from the time length information of each terminal device to obtain a second difference value corresponding to each terminal device; and select a terminal device with the largest second difference value from the plurality of terminal devices as the target device.

[0271] In another embodiment,

[0272] The finding module 901 is configured to perform a public land mobile network (PLMN) selection to find an available PLMN.

[0273] The selecting module 902 is configured to select a target device from the plurality of terminal devices according to the available PLMN and PLMN information stored by the first terminal device.

[0274] The registering module 903 is configured to initiate a registration access based on the stored security context of the target device.

[0275] Optionally, the plurality of terminal devices comprise a plurality of SIM cards belonging to the same operator.

[0276] Optionally, the PLMN information comprises a registered PLMN.

[0277] Optionally, the plurality of terminal devices are in a deregistered state.

[0278] Optionally, the finding module 901 is further configured to perform a PLMN selection to find the available PLMN based on a PLMN list, the PLMN list comprising at least one PLMN.

[0279] Optionally, the finding module 901 is further configured to select the available PLMN from the PLMN list based on a priority of each PLMN in the PLMN list.

[0280] Optionally, the PLMN list comprises at least one of the following PLMNs: a home public land mobile network (HPLMN), an equivalent home public land mobile network (EHPLMN), a user-controlled public land mobile network (UPLMN), an operator-controlled public land mobile network (OPLMN), or another PLMN.

[0281] Optionally, the selection module 902 is further configured to select the first terminal device as the target device when the available PLMN is the same as the registered PLMN stored by the first terminal device.

[0282] Optionally, the selection module 902 is further configured to obtain PLMN information stored by each of the plurality of terminal devices except the first terminal device, when the available PLMN is different from the registered PLMN stored by the first terminal device, to obtain the PLMN information stored by each of the plurality of terminal devices; and select the target device from the plurality of terminal devices according to the available PLMN and the PLMN information stored by each of the plurality of terminal devices.

[0283] Optionally, the selection module 902 is further configured to select a second terminal device as the target device when the registered PLMN stored by the second terminal device is the same as the available PLMN.

[0284] Optionally, the selection module 902 is further configured to obtain timestamp information of each of the plurality of terminal devices, when the registered PLMN stored by each of the plurality of terminal devices except the first terminal device is different from the available PLMN, the timestamp information comprising a time point at which the each of the plurality of terminal devices last deregistered; and select the target device from the plurality of terminal devices according to the timestamp information.

[0285] Optionally, the selection module 902 is further configured to select a first terminal device as the target device when the timestamp information of the first terminal device is later than that of a second terminal device; and select the second terminal device as the target device when the timestamp information of the first terminal device is earlier than that of the second terminal device.

[0286] Optionally, the selection module 902 is further configured to: when the registered PLMN stored by each terminal device in the plurality of terminal devices except the first terminal device is different from the available PLMN, acquire timestamp information and time length information of each terminal device in the plurality of terminal devices, the timestamp information including a time point at which the each terminal device last deregisters, and the time length information including a time length for which the network device maintains a security context of the each terminal device; and select the target device from the plurality of terminal devices according to the timestamp information and the time length information.

[0287] Optionally, the selection module 902 is further configured to: subtract the timestamp information of the each terminal device from a current time point to obtain a first difference value corresponding to the each terminal device; subtract the first difference value corresponding to the each terminal device from the time length information of the each terminal device to obtain a second difference value corresponding to the each terminal device; and select a terminal device with the largest second difference value from the plurality of terminal devices as the target device.

[0288] Optionally, the registration module 903 is further configured to: if a second terminal device is selected from the plurality of terminal devices as the target device, send first indication information, the first indication information being used to instruct the second terminal device to initiate registration access.

[0289] It should be noted that the implementation of each module can also correspond to the description of the corresponding method embodiments shown in FIG. 4, FIG. 6 and FIG. 8, and the method and function performed by the first device or the first terminal device in the first device in the above embodiments are executed.

[0290] FIG. 10 is a structural schematic diagram of a first device according to an embodiment of the present application. The first device can be applied to the system shown in FIG. 1, and perform the functions of the first device in the above method embodiments, or implement the steps or processes performed by the first device in the above method embodiments.

[0291] As shown in FIG. 10, the first device includes a processor 1001 and a transceiver 1002. Optionally, the first device further includes a memory 1003. The processor 1001, the transceiver 1002 and the memory 1003 can communicate with each other through internal connection paths, and transfer control and / or data signals. The memory 1003 is used to store a computer program, and the processor 1001 is used to call and run the computer program from the memory 1003 to control the transceiver 1002 to transceive signals. Optionally, the first device can further include an antenna used to send uplink data or uplink control signaling output by the transceiver 1002 through wireless signals.

[0292] The processor 1001 can correspond to the searching module and the selecting module in FIG. 4, FIG. 6 or FIG. 8. The processor 1001 and the memory 1003 can be combined into one processing device. The processor 1001 is configured to execute program codes stored in the memory 1003 to implement the above functions. In specific implementation, the memory 1003 can be integrated in the processor 1001 or independent of the processor 1001.

[0293] The transceiver 1002 can correspond to the registering module in FIG. 4, FIG. 6 or FIG. 8, and can also be referred to as a transceiving unit or a transceiving module. The transceiver 1002 can include a receiver (or receiver circuit) and a transmitter (or transmitter circuit). The receiver is configured to receive signals, and the transmitter is configured to transmit signals.

[0294] It should be understood that the first device shown in FIG. 10 can implement each process involving the first device in the method embodiments shown in FIG. 4, FIG. 6 or FIG. 8. The operations and / or functions of each module in the first device are respectively used to implement the corresponding processes in the above method embodiments. For details, refer to the description in the above method embodiments, and the detailed description is appropriately omitted here.

[0295] The processor 1001 can be used to execute the actions implemented by the first device described in the above method embodiments, and the transceiver 1002 can be used to execute the receiving or transmitting actions of the first device described in the above method embodiments. For details, refer to the description in the above method embodiments, and the detailed description is not repeated here.

[0296] The processor 1001 can be a central processing unit, a general purpose processor, a digital signal processor, an application specific integrated circuit, a field programmable gate array, or other programmable logic device, transistor logic, hardware components, or any combination thereof. It can implement or execute various example logical blocks, modules, and circuits described in connection with the disclosure. The processor 1001 can also be a combination of computing components, such as one or more microprocessors, a combination of a digital signal processor and a microprocessor, etc. The communication bus 1004 can be a peripheral component interconnect (PCI) bus or an extended industry standard architecture (EISA) bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, only one thick line is shown in FIG. 10, but it does not mean that there is only one bus or only one type of bus. The communication bus 1004 is used to realize the connection communication between the components. In the embodiment of the present application, the transceiver 1002 is used for signaling or data communication with other node devices. The memory 1003 can include volatile memory, such as non-volatile random access memory (NVRAM), phase change RAM (PRAM), magnetoresistive RAM (MRAM), etc., and can also include non-volatile memory, such as at least one magnetic disk storage device, electrically erasable programmable read-only memory (EEPROM), flash memory device, such as NOR flash memory or NAND flash memory, semiconductor device, such as solid state disk (SSD), etc. The memory 1003 can also be at least one storage device located away from the processor 1001. The memory 1003 can also optionally store a set of computer program codes or configuration information. Optionally, the processor 1001 can also execute the program stored in the memory 1003. The processor can cooperate with the memory and the transceiver to execute any method and function of the first device in the above embodiments.

[0297] The embodiments of the present application also provide a chip system, which includes a processor for supporting the first device to implement the functions involved in any of the above embodiments, such as generating or processing the PLMN information involved in the above method.

[0298] In one possible design, the chip system can further include a memory for computer programs and data necessary for the first device. The chip system can be composed of a chip, or can include a chip and other discrete devices. The input and output of the chip system correspond to the receiving and sending operations of the first device in the method embodiments, respectively.

[0299] According to the method provided in the embodiments of the present application, the present application further provides a computer program product, which includes a computer program. When the computer program is run on a computer, the computer program enables the computer to execute the method in any one of the embodiments shown in FIG. 4, FIG. 6 or FIG. 8.

[0300] According to the method provided in the embodiments of the present application, the present application further provides a computer readable medium, which stores a computer program. When the computer program is run on a computer, the computer program enables the computer to execute the method in any one of the embodiments shown in FIG. 4, FIG. 6 or FIG. 8.

[0301] In the above embodiments, the implementation can be achieved entirely or partially by software, hardware, firmware, or any combination thereof. When implemented by software, the implementation can be achieved entirely or partially in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer instructions are loaded and executed on a computer, the computer instructions entirely or partially generate the processes or functions described in the embodiments of the present application. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions can be stored in a computer readable storage medium, or transferred from one computer readable storage medium to another computer readable storage medium, for example, the computer instructions can be transferred from one website, computer, server, or data center to another website, computer, server, or data center through wired (for example, coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (for example, infrared, wireless, microwave, etc.) manner. The computer readable storage medium can be any available medium accessible by a computer or a data storage device such as a server, data center, etc. integrated with one or more available media. The available medium can be a magnetic medium (for example, floppy disk, hard disk, magnetic tape), an optical medium (for example, high-density digital video disc (DVD)), or a semiconductor medium (for example, solid state disc (SSD)), etc.

[0302] The above merely provides the specific implementation of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can easily think of the changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method of registering access, characterized by, The method is applied to a first device, the first device comprising a plurality of SIM cards, the method comprising: performing a public land mobile network (PLMN) selection to find available PLMNs; selecting a target SIM card from the plurality of SIM cards according to the available PLMNs and PLMN information stored in each of the plurality of SIM cards; initiating a registration access based on a security context stored in the target SIM card.

2. The method of claim 1, wherein, The plurality of SIM cards belong to a same operator.

3. The method of claim 1 or 2, wherein, The PLMN information comprises a registered PLMN.

4. The method according to any one of claims 1 to 3, characterized in that, The first device is in a de-registered state on the plurality of SIM cards.

5. The method according to any one of claims 1 to 4, characterized in that, The method further comprises: performing the PLMN selection to find the available PLMNs based on a PLMN list, the PLMN list comprising at least one PLMN.

6. The method of claim 5, wherein, The performing the PLMN selection to find the available PLMNs based on the PLMN list comprises: selecting a PLMN from the PLMN list to find the available PLMNs based on a priority of each PLMN in the PLMN list.

7. The method of claim 5 or 6, wherein, The PLMN list comprises at least one of a home public land mobile network (HPLMN), an equivalent home public land mobile network (EHPLMN), a user-controlled public land mobile network (UPLMN), an operator-controlled public land mobile network (OPLMN), or another PLMN.

8. The method according to any one of claims 1 to 7, wherein, The selecting the target SIM card from the plurality of SIM cards according to the available PLMNs and the PLMN information stored in each of the plurality of SIM cards comprises: when only one SIM card of the plurality of SIM cards stores PLMN information, selecting the SIM card storing the PLMN information as the target SIM card.

9. The method according to any one of claims 1 to 7, wherein The selecting the target SIM card from the plurality of SIM cards according to the available PLMNs and the PLMN information stored in each of the plurality of SIM cards comprises: when the available PLMNs are all the same as or all different from the registered PLMNs stored in each of the plurality of SIM cards, selecting a primary SIM card from the plurality of SIM cards as the target SIM card or selecting a SIM card from the plurality of SIM cards as the target SIM card.

10. The method of any one of claims 1-7, wherein, The selecting the target SIM card from the plurality of SIM cards according to the available PLMNs and the PLMN information stored in each of the plurality of SIM cards comprises: when the available PLMNs are the same as a registered PLMN stored in a first SIM card of the plurality of SIM cards and different from registered PLMNs stored in other SIM cards of the plurality of SIM cards except the first SIM card, selecting the first SIM card as the target SIM card.

11. The method of any one of claims 1-7, wherein, The selecting the target SIM card from the plurality of SIM cards according to the available PLMNs and the PLMN information stored in each of the plurality of SIM cards comprises: acquiring timestamp information of each SIM card in the plurality of SIM cards when the available PLMN is the same as or different from the registered PLMN stored in each SIM card, the timestamp information comprising a time point of last de-registration of each SIM card; selecting the target SIM card from the plurality of SIM cards according to the timestamp information.

12. The method of claim 11, wherein, The selecting the target SIM card from the plurality of SIM cards according to the timestamp information comprises: selecting a first SIM card as the target SIM card if the timestamp information of the first SIM card is later than the timestamp information of other SIM cards except the first SIM card.

13. A method of registering access, characterized by The method is applied to a first device, and the first device comprises a plurality of terminal devices, and the method comprises: acquiring an available public land mobile network (PLMN) for performing PLMN selection lookup; selecting a target device from the plurality of terminal devices according to the available PLMN and PLMN information stored in each terminal device in the plurality of terminal devices; initiating registration access based on a security context stored in the target device.

14. The method of claim 13, wherein, The plurality of SIM cards contained in the plurality of terminal devices belong to a same operator.

15. The method of claim 13 or 14, wherein, The PLMN information comprises a registered PLMN.

16. The method according to any one of claims 13 to 15, wherein, The plurality of terminal devices are all in a de-registered state.

17. The method of any one of claims 13-16, wherein, The available PLMN is selected from a PLMN list comprising at least one PLMN.

18. The method of claim 17, wherein, The available PLMN is selected based on a priority of each PLMN in the PLMN list.

19. The method of claim 17 or 18, wherein, The PLMN list comprises at least one of the following PLMNs: a home public land mobile network (HPLMN), an equivalent home public land mobile network (EHPLMN), a user-controlled public land mobile network (UPLMN), an operator-controlled public land mobile network (OPLMN), or another PLMN.

20. The method of any one of claims 13-19, wherein, The acquiring the available PLMN for performing PLMN selection lookup comprises: selecting a first terminal device from the plurality of terminal devices; acquiring the available PLMN for performing PLMN selection lookup by the first terminal device.

21. The method of any one of claims 13-20, wherein, The selecting the target device from the plurality of terminal devices according to the available PLMN and the PLMN information stored in each terminal device in the plurality of terminal devices comprises: when only one terminal device in the plurality of terminal devices stores PLMN information, selecting the terminal device storing the PLMN information as the target device.

22. The method of any one of claims 13-20, wherein, The selecting the target device from the plurality of terminal devices according to the available PLMN and the PLMN information stored in each terminal device in the plurality of terminal devices comprises: when the available PLMN is the same as or different from the registered PLMN stored in each terminal device, selecting a terminal device from the plurality of terminal devices as the target device or selecting a master device from the plurality of terminal devices as the target device.

23. The method of any one of claims 13-20, wherein, The selecting the target device from the plurality of terminal devices according to the available PLMN and the PLMN information stored in each terminal device in the plurality of terminal devices comprises: When the available PLMN is the same as a registration PLMN stored by a first terminal device in the plurality of terminal devices and is different from a registration PLMN stored by other terminal devices in the plurality of terminal devices except the first terminal device, the first terminal device is selected as the target device.

24. The method of any one of claims 13-20, wherein, The selecting the target device from the plurality of terminal devices according to the available PLMN and the PLMN information stored by each terminal device in the plurality of terminal devices comprises: When the available PLMN is the same as or different from the registration PLMN stored by each terminal device, obtaining timestamp information of each terminal device in the plurality of terminal devices, the timestamp information comprising a time point at which each terminal device last deregisters; The selecting the target device from the plurality of terminal devices according to the timestamp information comprises:

25. The method of claim 24, wherein, If the timestamp information of a first terminal device in the plurality of terminal devices is later than the timestamp information of other terminal devices except the first terminal device, the first terminal device is selected as the target device. The registration access device comprises a memory and a processor, the memory is configured to store a computer program, and the processor is configured to execute the computer program to enable the registration access device to perform the method in any one of claims 1-12 or any one of claims 13-25.

26. A registration access device, comprising: The computer readable storage medium comprises a computer program, when the computer program is executed by a processor, the method in any one of claims 1-12 or any one of claims 13-25 is enabled to be implemented.

27. A computer readable storage medium, characterized in that, The chip comprises a processor and a communication interface, the communication interface is configured to communicate with an external device or an internal device, and the processor is configured to implement the method in any one of claims 1-12 or any one of claims 13-25.

28. A chip, characterized by When the computer program is executed, the computer is enabled to perform the method in any one of claims 1-12 or any one of claims 13-25.

29. A computer program product comprising a computer program, characterised in that, ​

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