Communication method and communication device

Abstract

The invention relates to the field of communication, in particular to a communication method and a communication device. Cell switching can enable a terminal to be switched from one cell to another cell, however, cell switching may conflict with other cell change modes, resulting in that the terminal cannot be connected to a target cell. In the embodiments of the present application, a core network device or an access network device sends second information to a terminal to indicate cells for different switching modes. The terminal can select a second cell according to the second information after determining the switching mode, and if it is determined that the path is switched through the first switching mode, the second cell can be selected from the cells supporting the first switching mode; if it is determined that the path is switched through the second switching mode, a second cell can be selected from cells supporting the second switching mode; and the terminal selects one cell change mode based on the second information, so that the problem caused by conflicts of multiple cell change modes can be avoided.

Description

Technical Field

[0001] This application relates to the field of communications, and in particular, to a communication method and a communication device. Background Art

[0002] A cell can be regarded as an area that provides wireless signal coverage identified by a physical cell identifier (PCI) or a cell global identifier (CGI). The coverage area of each base station can be divided into one or more cells. A terminal can switch from one cell to another. Among them, the cell before the switch can be called the source cell or the anchor cell, and the cell after the switch can be called the target cell.

[0003] Cell switching enables a terminal to switch from a cell with a poor channel state to a cell with a better channel state, providing better communication services for users. In addition to cell switching, a terminal may also establish a connection with a target cell through other cell change methods. However, the target cell in cell switching may conflict with the target cell in other cell change methods, resulting in the terminal being unable to connect to the target cell. Summary of the Invention

[0004] Embodiments of this application provide a communication method, a communication device, a communication system, a computer-readable storage medium, and a computer program product, which can avoid problems caused by conflicts among multiple cell change methods.

[0005] In a first aspect, embodiments of this application provide a communication method. The execution subject of this method may be a terminal or a chip applied to a terminal. Hereinafter, the case where the execution subject is a terminal will be used as an example for description. The method includes: receiving second information through a first path, where the second information includes a first set and / or a second set, the first set indicating cells that support a first handover method, and the second set indicating cells that support a second handover method; determining to switch the first path to a second path through the first handover method or the second handover method, where the second path includes a connection between the terminal and a second cell. Among them, when switching the first path to the second path through the first handover method, the second cell belongs to the cells indicated by the first set, or the second cell does not belong to the cells indicated by the second set; or when switching the first path to the second path through the second handover method, the second cell belongs to the cells indicated by the second set, or the second cell does not belong to the cells indicated by the first set.

[0006] The handover methods applicable to different cells may be different. The first set and / or the second set indicate the cells corresponding to different handover methods. After determining the handover method, the terminal can select a second cell according to the second information. If it is determined to switch the path through the first handover method, the terminal can select a second cell from the cells that support the first handover method, or avoid selecting a second cell from the cells that support the second handover method. If it is determined to switch the path through the second handover method, the terminal can select a second cell from the cells that support the second handover method, or avoid selecting a second cell from the cells that support the first handover method. The terminal selects a cell change method based on the second information, which can avoid the problems caused by the conflict of multiple cell change methods.

[0007] Optionally, before receiving the second information through the first path, the method further includes: sending first information through the first path, where the first information indicates that the terminal supports multiple handover methods, and the multiple handover methods include a first handover method and a second handover method.

[0008] In various embodiments of the present application, "the first information indicates that the terminal supports multiple handover methods, and the multiple handover methods include a first handover method and a second handover method" can be expressed as: the first information indicates that the terminal supports the second handover method, or the first information indicates that the terminal can perform handover through the second handover method.

[0009] Since there may be terminals in the network that do not support the second handover method or do not support multiple handover methods, the terminal can send first information indicating that it supports the second handover method or multiple handover methods, so as to facilitate the network device to perform processing related to the second handover method.

[0010] Optionally, before determining to switch the first path to the second path through the first handover method or the second handover method, the method further includes: receiving third information through the first path, where the third information indicates that the terminal is allowed to perform multiple handover methods.

[0011] In various embodiments of the present application, "the third information indicates that the terminal is allowed to perform multiple handover methods" can be expressed as: the third information indicates that the terminal is allowed to perform the second handover method.

[0012] The third information is used to respond to the first information and clearly indicates that the terminal is allowed to perform multiple handover methods. If the terminal receives the third information, it can perform multiple handover methods. If the terminal does not receive the third information, it can switch the path according to the default handover method (such as the handover method based on cell handover), thereby avoiding the problems caused by the handover method performed by the terminal not being supported by the network device.

[0013] Optionally, before receiving the second information through the first path, the method further includes: sending fourth information through the first path, where the fourth information indicates that the terminal enables the mode of performing the second handover method.

[0014] In various embodiments of the present application, "enabling the mode of executing the second switching method" may also be expressed as: performing path switching through the second switching method, or activating the second switching method.

[0015] In some cases, when the terminal determines that the network device supports multiple switching methods, the fourth information may be used to indicate the requirements of the terminal, so that the network device can configure a set that meets the terminal requirements through the second information.

[0016] Optionally, the method further includes: if it is determined that the first path is switched to the second path through the second switching method, adjusting the signal quality value of the second cell from the first value to the second value, where the first value is greater than or equal to the signal quality value corresponding to the first switching method, and the second value is less than the signal quality value corresponding to the first switching method; sending the second value through the first path.

[0017] In various embodiments of the present application, "the first value is greater than or equal to the signal quality value corresponding to the first switching method, and the second value is less than the signal quality value corresponding to the first switching method" may be expressed as: the first value is greater than the signal quality value corresponding to the first switching method, and the second value is less than or equal to the signal quality value corresponding to the first switching method.

[0018] In some cases, the first switching method is triggered by the network device. To avoid triggering the first switching method, the terminal can modify the signal quality value to avoid the network device triggering the first switching method. This embodiment meets the path switching requirements of the terminal without modifying the triggering mechanism of the first switching method, improving the compatibility of the method.

[0019] Optionally, the method further includes: if it is determined that the first path is switched to the second path through the second switching method, sending the signal quality value of the second cell through the first path, where the signal quality value of the second cell is less than the signal quality value corresponding to triggering the execution of the first switching method.

[0020] In some cases, the first switching method is triggered by the network device. To avoid triggering the first switching method, the terminal can send the signal quality value of the second cell through the first path, or the terminal can send the signal quality value of the second cell through the first path without performing signal measurement, and the signal quality value is lower than the signal quality value corresponding to triggering the execution of the first switching method, so as to avoid the network device triggering the first switching method. This embodiment meets the path switching requirements of the terminal without modifying the triggering mechanism of the first switching method, improving the compatibility of the method.

[0021] Optionally, the first handover method is a handover method based on cell handover, the second handover method is a handover method based on dual connectivity, the first set is a first cell set, the second set is a second cell set, the public land mobile network (PLMN) corresponding to the cells in the first cell set is equivalent to the PLMN of the first cell, the PLMN corresponding to the cells in the second cell set is not equivalent to the PLMN of the first cell, and the first cell is the cell corresponding to the first path.

[0022] When the terminal transfers from the PLMN corresponding to the first cell to an equivalent PLMN, network selection is not required. When the terminal transfers from the PLMN corresponding to the first cell to a non-equivalent PLMN, network selection is required. Therefore, configuring the first set as a cell set of equivalent PLMNs is beneficial to the handover method based on cell handover, and configuring the second set as a cell set of non-equivalent PLMNs is beneficial to the handover method based on dual connectivity.

[0023] Optionally, the first handover method is a handover method based on cell handover, the second handover method is a handover method based on dual connectivity, the first set is a first PLMN set, the second set is a second PLMN set, the PLMNs in the first PLMN set are equivalent to the PLMN of the first cell, the PLMNs in the second PLMN set are not equivalent to the PLMN of the first cell, and the first cell is the cell corresponding to the first path.

[0024] When the terminal hands over from the PLMN corresponding to the first cell to a cell corresponding to an equivalent PLMN, network selection is not required. When the terminal hands over from the PLMN corresponding to the first cell to a cell corresponding to a non-equivalent PLMN, network selection is required. Therefore, configuring the first set as a set of equivalent PLMNs is beneficial to the handover method based on cell handover, and configuring the second set as a set of non-equivalent PLMNs is beneficial to the handover method based on dual connectivity.

[0025] Optionally, the first handover method is a handover method based on cell handover, the second handover method is a handover method based on dual connectivity, the first set is a first cell set, the second set is a second cell set, the PLMN corresponding to the cells in the first cell set is the same as the PLMN of the first cell, the PLMN corresponding to the cells in the second cell set is different from the PLMN of the first cell, and the first cell is the cell corresponding to the first path.

[0026] When the terminal switches from the cell corresponding to the first public land mobile network (PLMN) to a cell corresponding to the same PLMN, network selection is not required. When the terminal switches from the cell corresponding to the first PLMN to a cell corresponding to a different PLMN, network selection may be required. Therefore, configuring the first set as the set of cells of the same PLMN is beneficial to the handover method based on cell handover, and configuring the second set as the set of cells of different PLMNs is beneficial to the handover method based on dual connectivity.

[0027] Optionally, the first handover method is the handover method based on cell handover, the second handover method is the handover method based on dual connectivity, the first set is the first PLMN set, the second set is the second PLMN set, the PLMNs in the first PLMN set include the PLMN of the first cell, the PLMNs in the second PLMN set do not include the PLMN of the first cell, and the first cell is the cell corresponding to the first path.

[0028] When the terminal switches from the cell corresponding to the first PLMN to a cell corresponding to the same PLMN, network selection is not required. When the terminal switches from the cell corresponding to the first PLMN to a cell corresponding to a different PLMN, network selection may be required. Therefore, configuring the first set as the set of the same PLMNs is beneficial to the handover method based on cell handover, and configuring the second set as the set of different PLMNs is beneficial to the handover method based on dual connectivity.

[0029] In a second aspect, an embodiment of the present application provides a communication method. The execution subject of this method may be an access network device or a chip applied to an access network device. Hereinafter, the case where the execution subject is an access network device will be described as an example. The method includes: receiving permission information from a core network device, where the permission information indicates that the terminal is allowed to execute multiple handover methods, and the multiple handover methods include a first handover method and a second handover method; or, the permission information indicates that the terminal is allowed to execute the second handover method; according to the permission information, sending second information to the terminal, where the second information includes the first set and / or the second set, the first set indicates the cells supporting the first handover method, and the second set indicates the cells supporting the second handover method.

[0030] The handover methods applicable to different cells may be different. The first set and / or the second set indicate the cells corresponding to different handover methods. After determining the handover method, the terminal can select a second cell according to the second information. If it is determined to switch the path through the first handover method, the second cell can be selected from the cells supporting the first handover method, or the second cell can be avoided from being selected from the cells supporting the second handover method; if it is determined to switch the path through the second handover method, the second cell can be selected from the cells supporting the second handover method, or the second cell can be avoided from being selected from the cells supporting the first handover method; the terminal selects a cell change method based on the second information, which can avoid the problems caused by the conflict of multiple cell change methods.

[0031] Optionally, before receiving the permission information from the core network device, the method further includes: receiving first information from the terminal, where the first information indicates that the terminal supports multiple handover methods, and the multiple handover methods include a first handover method and a second handover method; sending the first information to the core network device.

[0032] Since there may be terminals in the network that do not support the second handover method or do not support multiple handover methods, the terminal can send the first information to indicate that it supports the second handover method or multiple handover methods, so as to facilitate the network device to perform processing related to the second handover method.

[0033] Optionally, the method further includes: sending third information to the terminal, where the third information indicates that the terminal is allowed to perform multiple handover methods, and the multiple handover methods include a first handover method and a second handover method.

[0034] The third information is used to respond to the first information and clearly indicates that the terminal is allowed to perform multiple handover methods. If the terminal receives the third information, it can perform multiple handover methods; if the terminal does not receive the third information, it can switch the path according to the default handover method (such as the handover method based on cell handover), so as to avoid problems caused by the handover method performed by the terminal not being supported by the network device.

[0035] Optionally, before sending the second information to the terminal, the method further includes: receiving fourth information from the terminal, where the fourth information indicates that the terminal enables the mode of performing the second handover method; sending the second information to the terminal, including: sending the second information to the terminal according to the fourth information.

[0036] In some cases, if the terminal determines that the network device supports multiple handover methods, it can indicate the requirements of the terminal through the fourth information, so as to facilitate the network device to configure a set that meets the requirements of the terminal through the second information.

[0037] Optionally, sending the second information to the terminal includes: sending the second information to the terminal through a first path, where the cell corresponding to the first path is a first cell; the permission information includes at least one of the following information: fifth information indicating that the access network device does not perform the first handover method; sixth information indicating that the access network device performs the second handover method; a first PLMN set, where the PLMNs in the first PLMN set are not equivalent to the PLMN of the first cell; seventh information indicating that the priority of the first handover method is lower than the priority of the second handover method.

[0038] In some cases, if the core network device does not want the access network device to perform the first handover method, the core network device can indicate to the access network device not to perform the first handover method through one or more pieces of information in the permission information. For example, the access network device can instruct the terminal not to perform operations related to the first handover method according to the permission information, or remove the cell in the first set that supports the first handover method, so as to avoid the terminal from performing the first handover method.

[0039] Optionally, the method further includes: sending an eighth piece of information to the core network device, where the eighth piece of information indicates that the handover method configuration of the terminal has been updated.

[0040] The eighth piece of information is used to respond to the permission information, so that the core network device can determine that the terminal has completed the update of the handover method configuration.

[0041] Optionally, sending the second piece of information to the terminal includes: sending the second piece of information to the terminal through a first path, where the cell corresponding to the first path is the first cell; the first handover method is a handover method based on cell handover, the second handover method is a handover method based on dual connectivity, the first set is a first cell set, the second set is a second cell set, the PLMN corresponding to the cells in the first cell set is equivalent to the PLMN of the first cell, and the PLMN corresponding to the cells in the second cell set is not equivalent to the PLMN of the first cell.

[0042] The terminal does not need to perform network selection when switching from the PLMN corresponding to the first cell to the cell corresponding to the equivalent PLMN, and the terminal needs to perform network selection when switching from the PLMN corresponding to the first cell to the cell corresponding to the non-equivalent PLMN. Therefore, configuring the first set as the cell set of the equivalent PLMN is beneficial to the handover method based on cell handover, and configuring the second set as the cell set of the non-equivalent PLMN is beneficial to the handover method based on dual connectivity.

[0043] Optionally, sending the second piece of information to the terminal includes: sending the second piece of information to the terminal through a first path, where the cell corresponding to the first path is the first cell; the first handover method is a handover method based on cell handover, the second handover method is a handover method based on dual connectivity, the first set is a first PLMN set, the second set is a second PLMN set, the PLMN in the first PLMN set is equivalent to the PLMN of the first cell, and the PLMN in the second PLMN set is not equivalent to the PLMN of the first cell.

[0044] When the terminal switches from the PLMN corresponding to the first cell to the cell corresponding to the equivalent PLMN, network selection is not required. When the terminal switches from the PLMN corresponding to the first cell to the cell corresponding to the non-equivalent PLMN, network selection is required. Therefore, configuring the first set as the equivalent PLMN set is beneficial for the handover method based on cell handover, and configuring the second set as the non-equivalent PLMN set is beneficial for the handover method based on dual connectivity.

[0045] Optionally, send the second information to the terminal, including: sending the second information to the terminal through the first path, where the cell corresponding to the first path is the first cell; the first handover method is the handover method based on cell handover, the second handover method is the handover method based on dual connectivity, the first set is the first cell set, the second set is the second cell set, the PLMNs corresponding to the cells in the first cell set are the same as the PLMN of the first cell, and the PLMNs corresponding to the cells in the second cell set are different from the PLMN of the first cell.

[0046] When the terminal switches from the PLMN corresponding to the first cell to the cell corresponding to the same PLMN, network selection is not required. When the terminal switches from the PLMN corresponding to the first cell to the cell corresponding to a different PLMN, network selection may be required. Therefore, configuring the first set as the cell set with the same PLMN is beneficial for the handover method based on cell handover, and configuring the second set as the cell set with different PLMNs is beneficial for the handover method based on dual connectivity.

[0047] Optionally, send the second information to the terminal, including: sending the second information to the terminal through the first path, where the cell corresponding to the first path is the first cell; the first handover method is the handover method based on cell handover, the second handover method is the handover method based on dual connectivity, the first set is the first PLMN set, the second set is the second PLMN set, the PLMNs in the first PLMN set include the PLMN of the first cell, and the PLMNs in the second PLMN set do not include the PLMN of the first cell.

[0048] When the terminal switches from the PLMN corresponding to the first cell to the cell corresponding to the same PLMN, network selection is not required. When the terminal switches from the PLMN corresponding to the first cell to the cell corresponding to a different PLMN, network selection may be required. Therefore, configuring the first set as the same PLMN set is beneficial for the handover method based on cell handover, and configuring the second set as the different PLMN set is beneficial for the handover method based on dual connectivity.

[0049] In a third aspect, an embodiment of the present application provides a communication method. The execution entity of this method can be an access network device or a chip applied to the access network device. Hereinafter, the case where the execution entity is an access network device will be described as an example. The method includes: receiving permission information from a core network device, where the permission information indicates that a terminal is allowed to perform multiple handover methods, and the multiple handover methods include a first handover method and a second handover method; or, the permission information indicates that the terminal is allowed to perform the second handover method; receiving fourth information from the terminal through a first path, where the fourth information indicates that the terminal enables a mode for performing the second handover method; determining, according to the permission information and the fourth information, not to enable a mode for performing the first handover method; or, sending second information to the terminal through the first path; or, sending updated information of the second information to the terminal through the first path; where the second information includes a first set and / or a second set, the first set indicates cells supporting the first handover method, and the second set indicates cells supporting the second handover method.

[0050] The handover methods applicable to different cells may be different. The first set and / or the second set indicate the cells corresponding to different handover methods. After determining the handover method, the terminal can select a second cell according to the second information. If it is determined to switch the path through the first handover method, it can select a second cell from the cells supporting the first handover method, or avoid selecting a second cell from the cells supporting the second handover method; if it is determined to switch the path through the second handover method, it can select a second cell from the cells supporting the second handover method, or avoid selecting a second cell from the cells supporting the first handover method; the terminal selects a cell change method based on the second information, which can avoid problems caused by conflicts between multiple cell change methods.

[0051] Optionally, before receiving the permission information from the core network device, the method further includes: receiving first information from the terminal through the first path, where the first information indicates that the terminal supports multiple handover methods, and the multiple handover methods include a first handover method and a second handover method; sending the first information to the core network device.

[0052] Since there may be terminals in the network that do not support the second handover method or do not support multiple handover methods, the terminal can send the first information to indicate that it supports the second handover method or multiple handover methods, so as to facilitate the network device to perform processing related to the second handover method.

[0053] Optionally, the method further includes: sending third information to the terminal through the first path, where the third information indicates that the terminal is allowed to perform multiple handover methods.

[0054] The third piece of information is used to respond to the first piece of information and clearly indicate that the terminal is allowed to perform multiple handover methods. If the terminal receives the third piece of information, it can perform multiple handover methods; if the terminal does not receive the third piece of information, it can switch the path according to the default handover method (such as the handover method based on cell handover), thereby avoiding problems caused by the handover method performed by the terminal not being supported by the network device.

[0055] Optionally, the permission information includes at least one of the following information: the fifth piece of information indicating that the access network device does not perform the first handover method; the sixth piece of information indicating that the access network device performs the second handover method; the first PLMN set, where the PLMNs in the first PLMN set are not equivalent to the PLMN of the first cell, and the first cell is the cell corresponding to the first path; the seventh piece of information indicating that the priority of the first handover method is lower than the priority of the second handover method.

[0056] In some cases, if the core network device does not want the access network device to perform the first handover method, the core network device can indicate to the access network device not to perform the first handover method through one or more pieces of information in the permission information. For example, the access network device can instruct the terminal not to perform operations related to the first handover method according to the permission information, or remove the cells in the first set that support the first handover method, thereby avoiding the terminal from performing the first handover method.

[0057] Optionally, the method further includes: sending an eighth piece of information to the core network device, where the eighth piece of information indicates that the handover method configuration of the terminal has been updated.

[0058] The eighth piece of information is used to respond to the permission information, so that the core network device can determine that the terminal has completed the update of the handover method configuration.

[0059] Optionally, the first handover method is a handover method based on cell handover, the second handover method is a handover method based on dual connectivity, the first set is the first cell set, the second set is the second cell set, the PLMNs corresponding to the cells in the first cell set are equivalent to the PLMN of the first cell, the PLMNs corresponding to the cells in the second cell set are not equivalent to the PLMN of the first cell, and the first cell is the cell corresponding to the first path.

[0060] The terminal does not need to perform network selection when switching from the PLMN corresponding to the first cell to the cell corresponding to the equivalent PLMN, and the terminal needs to perform network selection when switching from the PLMN corresponding to the first cell to the cell corresponding to the non-equivalent PLMN. Therefore, configuring the first set as the cell set of the equivalent PLMN is beneficial to the handover method based on cell handover, and configuring the second set as the cell set of the non-equivalent PLMN is beneficial to the handover method based on dual connectivity.

[0061] Optionally, the first handover method is a cell-based handover method, the second handover method is a dual-connection-based handover method, the first set is the first PLMN set, the second set is the second PLMN set, the PLMNs in the first PLMN set are equivalent to the PLMN of the first cell, the PLMNs in the second PLMN set are not equivalent to the PLMN of the first cell, and the first cell is the cell corresponding to the first path.

[0062] When the terminal hands over from the PLMN corresponding to the first cell to the cell corresponding to the equivalent PLMN, network selection is not required. When the terminal hands over from the PLMN corresponding to the first cell to the cell corresponding to the non-equivalent PLMN, network selection is required. Therefore, configuring the first set as the equivalent PLMN set is beneficial to the cell-based handover method, and configuring the second set as the non-equivalent PLMN set is beneficial to the dual-connection-based handover method.

[0063] Optionally, the first handover method is a cell-based handover method, the second handover method is a dual-connection-based handover method, the first set is the first cell set, the second set is the second cell set, the PLMNs corresponding to the cells in the first cell set are the same as the PLMN of the first cell, the PLMNs corresponding to the cells in the second cell set are different from the PLMN of the first cell, and the first cell is the cell corresponding to the first path.

[0064] When the terminal hands over from the PLMN corresponding to the first cell to the cell corresponding to the same PLMN, network selection is not required. When the terminal hands over from the PLMN corresponding to the first cell to the cell corresponding to a different PLMN, network selection may be required. Therefore, configuring the first set as the cell set with the same PLMN is beneficial to the cell-based handover method, and configuring the second set as the cell set with different PLMNs is beneficial to the dual-connection-based handover method.

[0065] Optionally, the first handover method is a cell-based handover method, the second handover method is a dual-connection-based handover method, the first set is the first PLMN set, the second set is the second PLMN set, the PLMNs in the first PLMN set include the PLMN of the first cell, the PLMNs in the second PLMN set do not include the PLMN of the first cell, and the first cell is the cell corresponding to the first path.

[0066] When the terminal hands over from the PLMN corresponding to the first cell to the cell corresponding to the same PLMN, network selection is not required. When the terminal transfers from the PLMN corresponding to the first cell to a different PLMN, network selection may be required. Therefore, configuring the first set as the same PLMN set is beneficial to the cell-based handover method, and configuring the second set as the different PLMN set is beneficial to the dual-connection-based handover method.

[0067] Fourthly, an embodiment of the present application provides a communication method. The execution subject of this method may be a core network device or a chip applied to a core network device. Hereinafter, the case where the execution subject is a core network device will be described as an example. The method includes: determining permission information, where the permission information indicates that the terminal is allowed to perform multiple handover methods, and the multiple handover methods include a first handover method and a second handover method; or, the permission information indicates that the terminal is allowed to perform the second handover method; and sending the permission information.

[0068] The handover methods applicable to different core network devices may be different. If a core network device supports a new handover method (such as the second handover method), the core network device may indicate that the terminal is allowed to perform multiple handover methods or the second handover method, so as to avoid problems caused by the incompatibility between the handover method determined by the terminal and the handover method supported by the core network device, and also avoid problems caused by conflicts between multiple cell change methods.

[0069] Optionally, before sending the permission information, the method further includes: receiving first information, where the first information indicates that the terminal supports multiple handover methods, and the multiple handover methods include a first handover method and a second handover method.

[0070] Since there may be terminals in the network that do not support the second handover method or do not support multiple handover methods, the terminal may send the first information to indicate that it supports the second handover method or multiple handover methods, so as to facilitate the network device to perform processing related to the second handover method.

[0071] Optionally, the permission information includes at least one of the following information: fifth information, indicating that the access network device does not perform the first handover method; sixth information, indicating that the access network device performs the second handover method; a first PLMN set, where the PLMNs in the first PLMN set are not equivalent to the PLMN of the first cell, and the first cell is the cell corresponding to the first path, and the first path includes the connection between the terminal and the access network device; seventh information, indicating that the priority of the first handover method is lower than the priority of the second handover method.

[0072] In some cases, if the core network device does not want the access network device to perform the first handover method, the core network device may indicate that the access network device does not perform the first handover method through one or more pieces of information in the permission information. For example, the access network device may instruct the terminal not to perform operations related to the first handover method according to the permission information, or remove the cells in the first set that support the first handover method, so as to avoid the terminal from performing the first handover method.

[0073] Optionally, the permission information includes a first set and / or a second set, where the first set indicates the PLMNs that support the first handover method, and the second set indicates the PLMNs that support the second handover method.

[0074] The core network device sends the first set and / or the second set through the permission information, which is beneficial for the access network device or the terminal to determine the cells corresponding to different handover methods.

[0075] Optionally, the first handover method is a handover method based on cell handover, the second handover method is a handover method based on dual connectivity, the first set is the first PLMN set, the second set is the second PLMN set, the PLMNs in the first PLMN set are equivalent to the PLMN of the first cell, the PLMNs in the second PLMN set are not equivalent to the PLMN of the first cell, the first cell is the cell corresponding to the first path, and the first path includes the connection between the terminal and the access network device.

[0076] The terminal does not need to perform network selection when switching from the PLMN corresponding to the first cell to the cell corresponding to the equivalent PLMN, and the terminal needs to perform network selection when switching from the PLMN corresponding to the first cell to the cell corresponding to the non-equivalent PLMN. Therefore, configuring the first set as the equivalent PLMN set is beneficial for the handover method based on cell handover, and configuring the second set as the non-equivalent PLMN set is beneficial for the handover method based on dual connectivity.

[0077] Optionally, the first handover method is a handover method based on cell handover, the second handover method is a handover method based on dual connectivity, the first set is the first PLMN set, the second set is the second PLMN set, the PLMNs in the first PLMN set include the PLMN of the first cell, the PLMNs in the second PLMN set do not include the PLMN of the first cell, the first cell is the cell corresponding to the first path, and the first path includes the connection between the terminal and the access network device.

[0078] The terminal does not need to perform network selection when switching from the PLMN corresponding to the first cell to the cell corresponding to the same PLMN, and the terminal may need to perform network selection when switching from the PLMN corresponding to the first cell to the cell corresponding to a different PLMN. Therefore, configuring the first set as the cell set of the same PLMN is beneficial for the handover method based on cell handover, and configuring the second set as the cell set of different PLMNs is beneficial for the handover method based on dual connectivity.

[0079] Optionally, the method further includes: receiving eighth information, where the eighth information indicates that the handover method configuration of the terminal has been updated.

[0080] The eighth information is used to respond to the permission information, so that the core network device can determine that the terminal has completed the update of the handover method configuration.

[0081] Fifth aspect, an embodiment of the present application provides a communication device. The communication device may include a processing unit and a transceiver unit, and is configured to execute: any method in the first aspect and its optional embodiments, or, any method in the second aspect and its optional embodiments, or, any method in the third aspect and its optional embodiments, or, any method in the fourth aspect and its optional embodiments; wherein, when the transceiver unit executes the sending step, it is a sending unit, and when the transceiver unit executes the receiving step, it is a receiving unit.

[0082] Sixth aspect, an embodiment of the present application provides a communication device, which may be a terminal or a chip applied to a terminal. The communication device may include a processor, and is configured to execute: any method in the first aspect and its optional embodiments.

[0083] Optionally, when the communication device is a terminal, the processor is, for example, a system on chip (SoC) or a central processing unit (CPU); when the communication device is a chip, the processor is, for example, a core, and the core may include at least one execution unit, and the execution unit is, for example, an arithmetic logic unit (ALU).

[0084] Optionally, the communication device may further include a transceiver. When the communication device is a terminal, the transceiver may be a transceiver circuit, an antenna, etc.; when the communication device is a chip, the transceiver may be an input / output interface, a pin, a circuit, etc.

[0085] Optionally, the communication device may further include a memory, and the memory is used to store computer programs or instructions. The processor executes the computer programs or instructions stored in the memory, so that the communication device executes any method in the first aspect and its optional embodiments. When the communication device is a terminal, the memory may be a read-only memory, a random access memory, etc.; when the communication device is a chip, the memory may be a register, a cache, etc.

[0086] Seventh aspect, an embodiment of the present application provides a communication device, which may be an access network device or a chip applied to an access network device. The communication device may include a processor, and is configured to execute: any method in the second aspect and its optional embodiments, or, any method in the third aspect and its optional embodiments.

[0087] Optionally, when the communication device is an access network device, the processor is, for example, a CPU, an application specific integrated circuit (ASIC), or a field programmable gate array (FPGA); when the communication device is a chip, the processor is, for example, a core, and the core may include at least one execution unit, and the execution unit is, for example, an ALU.

[0088] Optionally, the communication device may further include a transceiver. When the communication device is an access network device, the transceiver may be a transceiver circuit, an antenna, etc.; when the communication device is a chip, the transceiver may be an input / output interface, a pin, a circuit, etc.

[0089] Optionally, the communication device may further include a memory for storing computer programs or instructions, and the processor executes the computer programs or instructions stored in the memory, so that the communication device executes any method in the second aspect and its optional embodiments, or so that the communication device executes any method in the third aspect and its optional embodiments. When the communication device is an access network device, the memory may be a read-only memory, a random access memory, etc.; when the communication device is a chip, the memory may be a register, a cache, etc.

[0090] In an eighth aspect, an embodiment of the present application provides a communication device, which may be a core network device or a chip applied to a core network device. The communication device may include a processor for executing: any method in the fourth aspect and its optional embodiments.

[0091] Optionally, when the communication device is a core network device, the processor is, for example, a CPU, an ASIC, or an FPGA; when the communication device is a chip, the processor is, for example, a core, and the core may include at least one execution unit, and the execution unit is, for example, an ALU.

[0092] Optionally, the communication device may further include a transceiver. When the communication device is a core network device, the transceiver may be a transceiver circuit, an antenna, etc.; when the communication device is a chip, the transceiver may be an input / output interface, a pin, a circuit, etc.

[0093] Optionally, the communication device may further include a memory for storing computer programs or instructions, and the processor executes the computer programs or instructions stored in the memory to enable the communication device to execute any of the methods in the fourth aspect and its optional embodiments. When the communication device is a core network device, the memory may be a read-only memory, a random access memory, etc.; when the communication device is a chip, the memory may be a register, a cache, etc.

[0094] In a ninth aspect, an embodiment of the present application provides a communication system, which includes at least two of the following communication devices:

[0095] A communication device that executes any of the methods in the first aspect and its optional embodiments;

[0096] A communication device that executes any of the methods in the second aspect and its optional embodiments, or a communication device that executes any of the methods in the third aspect and its optional embodiments;

[0097] A communication device that executes any of the methods in the fourth aspect and its optional embodiments.

[0098] In a tenth aspect, an embodiment of the present application provides a computer-readable storage medium storing a computer program, which, when executed on a communication device, enables the communication device to execute: any of the methods in the first aspect and its optional embodiments, or any of the methods in the second aspect and its optional embodiments, or any of the methods in the third aspect and its optional embodiments, or any of the methods in the fourth aspect and its optional embodiments.

[0099] In an eleventh aspect, an embodiment of the present application provides a computer program product, which includes: computer program code or computer program instructions, which, when run on a communication device, enable the communication device to execute: any of the methods in the first aspect and its optional embodiments, or any of the methods in the second aspect and its optional embodiments, or any of the methods in the third aspect and its optional embodiments, or any of the methods in the fourth aspect and its optional embodiments. Description of the Drawings

[0100] Figure 1 is a schematic diagram of the architecture of the communication system to which the embodiment of the present application is applied;

[0101] Figure 2 is a schematic diagram of an architecture of the core network provided by the embodiment of the present application;

[0102] Figure 3It is another schematic diagram of the core network provided by the embodiments of the present application;

[0103] Figure 4 It is a schematic diagram of a cell handover scenario provided by the embodiments of the present application;

[0104] Figure 5 It is a schematic diagram of a cell handover based on the Xn interface provided by the embodiments of the present application;

[0105] Figure 6 It is a schematic diagram of a registration process provided by the embodiments of the present application;

[0106] Figure 7 It is a schematic diagram of a dual-connection scenario provided by the embodiments of the present application;

[0107] Figure 8 It is a schematic diagram of another dual-connection scenario provided by the embodiments of the present application;

[0108] Figure 9 It is a schematic diagram of a communication method provided by the embodiments of the present application;

[0109] Figure 10 It is a schematic diagram of another communication method provided by the embodiments of the present application;

[0110] Figure 11 It is a schematic diagram of another communication method provided by the embodiments of the present application;

[0111] Figure 12 It is a schematic diagram of another communication method provided by the embodiments of the present application;

[0112] Figure 13 It is a schematic diagram of the structure of a communication device provided by the embodiments of the present application;

[0113] Figure 14 It is a schematic diagram of the structure of another communication device provided by the embodiments of the present application. Detailed implementation manners

[0114] Next, the technical solutions in the present application will be described with reference to the accompanying drawings.

[0115] Figure 1 It is a schematic diagram of the architecture of the communication system 1000 applied in the embodiments of the present application. As Figure 1 shown, the communication system includes a radio access network (RAN) 100, where the RAN 100 includes at least one RAN node (such as Figure 1 110a - 110b in Figure 1Among 120a - 120j (collectively referred to as 120). RAN 100 may also include other RAN nodes, such as, for example, wireless relay devices and / or wireless backhaul devices ( Figure 1 not shown in the figure). The terminal 120 is connected to the RAN node 110 wirelessly. Terminals can be connected to each other and RAN nodes can be connected to each other either wired or wirelessly. The communication system 1000 may also include a core network (CN) 200. The RAN node 110 is connected to the core network 200 either wirelessly or wired. The core network devices in the core network 200 and the RAN nodes 110 in the RAN 100 can be separate different physical devices, or can be the same physical device integrating the logical functions of the core network devices and the logical functions of the RAN nodes. The communication system 1000 may also include the Internet 300.

[0116] RAN 100 can be an evolved universal terrestrial radio access (E-UTRA) system, a new radio (NR) system, or a future wireless access system defined in the 3rd generation partnership project (3GPP), or can be a WiFi system. RAN 100 may also include two or more different wireless access systems as described above. RAN 100 can also be an open RAN (O-RAN).

[0117] A RAN node, also known as a network device, access network device, wireless access network device, RAN entity, or access node, is used to assist a terminal in accessing a communication system wirelessly. Optionally, a RAN node can also be simply referred to as RAN.

[0118] In one application scenario, a RAN node can be a base station, an evolved NodeB (eNodeB), a transmission reception point (TRP), a next generation NodeB (gNB) in a 5th generation (5G) mobile communication system, a next generation NodeB in a 6th generation (6G) mobile communication system, a base station in a future mobile communication system, an access point (AP) in a WiFi system, an AP in a long range radio (LoRa) system, or an AP in a vehicle-to-everything (V2X) system. A RAN node can be a macro base station (such asFigure 1 in 110a) of Figure 1 it can also be a small base station or an indoor station (such as 110b) of

[0119] In another application scenario, the cooperation of multiple RAN nodes can be used to help a terminal achieve wireless access, and different RAN nodes respectively implement some functions of a base station. For example, the RAN node can be a central unit (CU), a distributed unit (DU), or a radio unit (RU). Here, the CU completes the functions of the radio resource control (RRC) protocol and the packet data convergence protocol (PDCP) of the base station, and can also complete the function of the service data adaptation protocol (SDAP); the DU completes the functions of the radio link control (RLC) layer and the medium access control (MAC) layer of the base station, and can also complete some functions of the physical (PHY) layer or all functions of the physical layer. For the specific descriptions of the above various protocol layers, reference can be made to the relevant technical specifications of 3GPP. The RU can be used to implement the functions of transceiver of radio frequency signals. The CU and the DU can be set as two independent RAN nodes, or can be integrated in the same RAN node, for example, integrated in the baseband unit (BBU). The RU can be included in the radio frequency device, for example, included in the remote radio unit (RRU), the active antenna unit (AAU), or the remote radio head (RRH). The CU can be further divided into two types of RAN nodes, namely, the central unit control plane (CU-CP) and the central unit user plane (CU-UP).

[0120] In different systems, RAN nodes may have different names. For example, in the O-RAN system, the CU can be called an open CU (O-CU), the DU can be called an open DU (O-DU), and the RU can be called an open RU (O-RU). The RAN nodes in the embodiments of this application can be implemented by software modules, hardware modules, or a combination of software modules and hardware modules. For example, the RAN node can be a server loaded with the corresponding software module. The embodiments of this application do not limit the specific technologies and specific device forms adopted by the RAN nodes. For ease of description, in the following text, the base station is used as an example of the RAN node for description.

[0121] A terminal is a device with wireless transceiver functions that can send signals to a base station or receive signals from a base station. A terminal can also be referred to as a terminal device, user equipment (UE), mobile station, mobile terminal, etc. Terminals can be widely applied in various scenarios, such as device-to-device (D2D), vehicle-to-everything (V2X) communication, machine-type communication (MTC), Internet of Things (IoT), virtual reality (VR), augmented reality (AR), industrial control, autonomous driving, remote medical treatment, smart grid, smart furniture, smart office, smart wearables, smart transportation, smart city, etc. The terminal can be a mobile phone (such as Figure 1 120a, 120e, 120f, and 120j in Figure 1 ), a laptop computer (such as Figure 1 120g in Figure 1 ), a printer with wireless transceiver functions (such as Figure 1 120h in Figure 1 ), a wearable device, a vehicle (such as Figure 1 120b in Figure 1 ), a charging pile (such as Figure 1 120c in

[0122] By way of example and not limitation, in the embodiments of the present application, a wearable device may also be referred to as a wearable intelligent device, which is a general term for devices developed by applying wearable technologies to the intelligent design of daily wear, such as glasses, gloves, watches, clothing, shoes, etc. A wearable device is a portable device that is worn directly on the body or integrated into the user's clothing or accessories. A wearable device is not just a hardware device, but also realizes powerful functions through software support, data interaction, and cloud interaction. Broadly speaking, wearable intelligent devices include electronic devices with complete functions, large sizes, and the ability to achieve complete or partial functions without relying on a smartphone, such as smart watches or smart glasses, or electronic devices that only focus on a certain type of application function and need to cooperate with other devices such as smartphones, such as various smart bracelets and smart jewelry for measuring physical signs.

[0123] By way of example and not limitation, in the embodiments of the present application, a vehicle may be a smart car (smart car or intelligent car), digital car, unmanned car (unmanned car, driverless car, pilotless car or automobile), self-driving car (self-driving car or autonomous car) or electric vehicle (electric vehicle, EV), where EV may be a pure electric vehicle (pure EV or battery EV), hybrid electric vehicle (hybrid electric vehicle, HEV), range extended electric vehicle (range extended EV, REEV), plug-in hybrid electric vehicle (plug-in HEV, PHEV) or new energy vehicle. Any of the above-described terminals, if located on a vehicle (e.g., placed inside or installed inside the vehicle), can be considered an in-vehicle terminal, and the in-vehicle terminal may also be referred to as an in-vehicle module, in-vehicle chip or on-board unit (OBU).

[0124] The base station and the terminal can be fixed or movable. The base station and the terminal can be deployed on land, including indoor or outdoor, handheld or vehicle-mounted; they can also be deployed on the water surface; they can also be deployed on airplanes, balloons and artificial satellites. The embodiments of the present application do not limit the application scenarios of the base station and the terminal.

[0125] The roles of the base station and the terminal can be relative. For example, Figure 1The 120i (which can be a helicopter or a drone) in it can be configured as a mobile base station. For the 120j that accesses the radio access network 100 through the 120i, the 120i is a base station; but for the 110a, the 120i is a terminal, that is, the communication between the 110a and the 120i is through the radio air interface protocol. Of course, the communication between the 110a and the 120i can also be through the interface protocol between base stations. At this time, relative to the 110a, the 120i is also a base station. Therefore, both base stations and terminals can be uniformly referred to as communication devices. Figure 1 The 110a and 110b in it can be called communication devices with base station functions. Figure 1 The 120a - 120j in it can be called communication devices with terminal functions.

[0126] The communication between base stations and terminals, between base stations and base stations, and between terminals and terminals can be carried out through authorized spectrum, can also be carried out through unlicensed spectrum, or can also be carried out through both authorized spectrum and unlicensed spectrum at the same time; it can communicate through the spectrum below 6 gigahertz (GHz), can also communicate through the spectrum above 6 GHz, and can also use the spectrum below 6 GHz and the spectrum above 6 GHz at the same time. The embodiments of this application do not limit the spectrum resources used for wireless communication.

[0127] In the embodiments of this application, the functions of the base station can also be executed by modules (such as chips) in the base station, or can also be executed by a control subsystem containing base station functions. Here, the control subsystem containing base station functions can be the control center in the above application scenarios such as smart grid, industrial control, intelligent transportation, and smart city. The functions of the terminal can also be executed by modules (such as chips or modems) in the terminal, or can also be executed by a device containing terminal functions.

[0128] Next, a brief introduction to the functions of the core network 200 will be given.

[0129] The main functions of the core network 200 are to provide user connection, user management, and service bearer, and to provide an interface to an external network (such as the Internet 300) as a bearer network. Optionally, the core network 200 can be divided into Figure 2 or Figure 3 the architectures shown. Among them, Figure 2 describes the core network based on the non-service-based architecture, Figure 3 describes the core network based on the service-based architecture (SBA).

[0130] The SBA is mainly reflected in the control plane. The essence of the SBA is to define network functions as several "service" modules that can be flexibly invoked in accordance with the three principles of "self - contained, reusable, and independently managed". Based on this, operators can flexibly customize the network according to business requirements. The interaction between network functions is realized through service invocations. Each network function presents a common service - oriented interface externally and can be invoked by authorized network functions or services.

[0131] As Figure 2 or Figure 3 shown, the core network 200 includes a user plane function (UPF), an access and mobility management function (AMF), a session management function (SMF), a unified data management function (UDM), and an authentication server function (AUSF).

[0132] The above - mentioned UPF, AMF, SMF, UDM, and AUSF can be referred to as core network elements or core network devices. These network elements can be independent hardware devices, or modules integrated in the same hardware device to implement different functions, or software functions running on dedicated hardware or virtualized functions instantiated on a cloud platform. The embodiments of the present application do not limit the specific form of the core network elements.

[0133] The following Figure 2 or Figure 3 briefly introduces the core network elements in

[0134] The UPF, which can also be called the user plane device, the user plane function network element, the user plane network element, or the user plane function entity, can be understood as the naming of the user plane function network element in 5G. The user plane function network element mainly includes the following functions: packet routing and transmission, packet detection, service usage reporting, QoS processing, lawful interception, uplink packet detection, downlink packet storage, and other user - plane - related functions.

[0135] Optionally, the UPF can be divided into a protocol data unit (PDU) session anchor UPF (PSA-UPF) and an intermediate UPF (I-UPF). Among them, the PSA-UPF is a UPF that supports the PDU session anchor function and is a UPF connected to the DN through the N6 interface, responsible for data transmission between the core network and the DN; all UPFs between the RAN and the PSA-UPF can be called I-UPFs. The I-UPF can be connected to the RAN through the N3 interface, and the I-UPF can be connected to the PSA-UPF through the N9 interface.

[0136] The AMF, which can also be referred to as the mobility management device, can be understood as the naming of the mobility management network element in the 5G architecture. The mobility management network element mainly includes the following functions: connection management, mobility management, registration management, access authentication and authorization, reachability management, security context management, and other access and mobility-related functions.

[0137] The SMF can be understood as the naming of the session management function network element in the 5G architecture. The session management function network element mainly performs functions such as session management, execution of the control policy issued by the policy control function (PCF), selection of the UPF, and allocation of the UE internet protocol (IP) address.

[0138] The UDM, which can also be referred to as the unified data management network element, the unified data management entity, or the data management device, can be understood as the naming of the unified data management network element in the 5G architecture. It is mainly used to process terminal device identification, access authentication, registration, and mobility management, etc.

[0139] The AUSF, which can also be referred to as the authentication service function network element, the authentication service function entity, the authentication service device, or the authentication device, can be understood as the naming of the authentication service function network element in the 5G architecture. The authentication service function network element is mainly used for user authentication. For example, after receiving an authentication request initiated by a subscribed user, the authentication service function network element can authenticate and / or authorize the subscribed user through the authentication information and / or authorization information stored in the unified data management network element, or generate the authentication and / or authorization information of the subscribed user through the unified data management network element. The authentication service function network element can feedback the authentication information and / or authorization information to the subscribed user. In a possible implementation, the authentication service function network element can also be co-located with the unified data management network element.

[0140] DN is an example of the Internet 300, which is a network outside the operator network. The operator network (such as the core network 200) can access multiple DNs. Multiple services can be deployed on the DN, providing services such as data and / or voice for terminal devices. For example, the DN is a private network of a smart factory. The sensors installed in the workshop of the smart factory can be terminal devices. A control server for the sensors is deployed in the DN, and the control server can provide services for the sensors. The sensors can communicate with the control server, obtain instructions from the control server, and transmit the collected sensor data to the control server according to the instructions. Another example is that the DN is the internal office network of a company. The mobile phones or computers of the company's employees can be terminal devices, and the mobile phones or computers of the employees can access information, data resources, etc. on the company's internal office network.

[0141] Figure 2 In, Uu, N1, N2, N3, N4, N6, N8, N9, N10, N11, N12, N13, and N14 are interface numbers. Among them, the dotted lines corresponding to N9 and N14 indicate that these two interfaces are optional interfaces. Figure 3 In, Namf is the service-based interface corresponding to AMF, Nsmf is the service-based interface corresponding to SMF, Nausf is the service-based interface corresponding to AUSF, and Nudm is the service-based interface corresponding to UDM. Figure 2 and Figure 3 The meanings of these interfaces shown can be referred to the meanings defined in the 3GPP standard protocol and are not restricted here.

[0142] The above network architecture is only an exemplary illustration. The network architecture applicable to the embodiments of this application is not limited to this. Any network architecture that can implement the functions of the above-mentioned network elements is applicable to the embodiments of this application.

[0143] The above naming is only defined for the convenience of distinguishing different functions and should not constitute any limitation to this application. This application does not exclude the possibility of using other naming in 5G networks and future other networks. For example, in 6G networks, some or all of the above-mentioned network elements may continue to use the terms in 5G, or other names may be adopted. The above interface names are also just an example. In specific implementations, the names of the interfaces may be other names, and this application does not make specific limitations on this.

[0144] For the convenience of understanding the embodiments of this application, the technologies involved in the embodiments of this application are briefly introduced below.

[0145] 1. Cell handover.

[0146] A cell can be regarded as a wireless signal coverage area identified by PCI or CGI. The coverage area of each base station can be divided into one or more cells. In WiFi, the range covered by the signal of a wireless access point (AP) can also be regarded as one or more cells. In the embodiments of the present application, different cells can correspond to different base stations, that is, different cells can be managed by different base stations, or different cells can belong to different RANs.

[0147] The above description of cells is an example rather than a limitation. With the development of technology, concepts similar or identical to the functions of cells may emerge, and these concepts are also applicable to the embodiments of the present application.

[0148] Due to the mobility of the terminal or the change of the channel state, the cell to which the terminal is connected will change, that is, the terminal can switch from one cell to another. Among them, the cell before the switch can be called the source cell or the anchor cell, and the cell after the switch can be called the target cell. As an optional example, cell switching can be interpreted as the terminal performing data transmission on the target cell and stopping data transmission on the source cell, or cell switching can be interpreted as the change of the transmission cell.

[0149] Figure 4 is a schematic diagram of a cell switching scenario.

[0150] Figure 4 In the figure, cell 1 and cell 2 belong to different RANs respectively. The terminal is currently performing data transmission in cell 1. As the terminal moves from cell 1 to cell 2, the channel state of cell 1 deteriorates. The terminal can use cell 2 for transmission and no longer use cell 1 for data transmission. Then cell 1 can be called the source cell, and cell 2 can be called the target cell. The process from transmitting data through cell 1 to transmitting data through cell 2 can be called cell switching.

[0151] It should be noted that cell switching can be triggered by the base station, can also be triggered by the terminal, or can be triggered by a third-party device other than the base station and the terminal.

[0152] Cell switching can be divided into switching based on the Xn interface and switching based on the N2 interface. These two cases are introduced separately below.

[0153] 1.1. Cell switching based on the Xn interface.

[0154] Figure 5It is a schematic diagram of cell handover based on the Xn interface provided by an embodiment of the present application. The Xn interface is an interface between base stations. If the signal quality of the source cell is poor and the terminal needs to hand over to the target cell, cell handover based on the Xn interface can be implemented. During the cell handover process based on the Xn interface, the AMF serving the terminal usually remains unchanged.

[0155] S501, Cell handover preparation.

[0156] Before performing the handover, the terminal and the source cell need to perform handover preparation operations. For example, the source cell will configure the terminal to perform a measurement process. The terminal measures the signal quality of surrounding cells (including the target cell) according to the measurement configuration and reports the measurement report to the source cell. The source cell will decide to perform the handover process for the terminal based on the measurement report.

[0157] S502, The source cell sends a RAN Usage data report to the AMF.

[0158] If the PLMN configures the use of data reports for the second radio access technology (RAT), then the source cell can provide a RAN Usage data report to the AMF. This report can include content such as N2 session information (N2 SM Information).

[0159] S503, The target cell sends a N2 Path Switch Request to the AMF.

[0160] The target cell sends a N2 Path Switch Request message to the AMF, notifying the AMF that the terminal has moved to the new cell and providing the list of PDU sessions to be handed over. The N2 Path Switch Request message can include content such as N2 SM Information.

[0161] S504, The AMF sends a Nsmf_PDUSession_UpdateSMContextRequest to the SMF.

[0162] After receiving the N2 SM Information from the source cell and the target cell, the AMF caches the relevant information and sends this N2 SM Information to the SMF.

[0163] S505, The SMF sends a N4 Session Modification Request to the UPF.

[0164] According to the network deployment, the CN tunnel information (CN TunnelInfo) of the UPF used to connect the target cell and the source cell may be different. If the CN tunnel information of the UPF needs to be reallocated, the CN tunnel information is allocated by the SMF, and the SMF can provide the CN tunnel information to the UPF through an N4 session modification request.

[0165] At S506, the UPF sends an N4 session modification response (N4 Session Modification Response) to the SMF.

[0166] The UPF can send an N4 session modification response to the SMF after the PDU session handover corresponding to the N4 session modification request. Optionally, for a PDU session where the user plane resources are not released, if the UPF has allocated CN tunnel information and different CN tunnel information needs to be allocated, the UPF can carry the tunnel information of the uplink traffic in the N4 session modification response.

[0167] At S507, the UPF sends an N3 end marker (N3 End Marker).

[0168] The UPF can send one or more "End Marker" data tables for each N3 tunnel on the old path after the path switch to assist the target cell in reordering. Subsequently, the UPF can send downlink data to the target cell.

[0169] At S508, the SMF sends a session context response (Nsmf_PDUSession_UpdateSMContextResponse) to the AMF.

[0170] For a successfully switched PDU session, the SMF sends the CN tunnel information to the AMF through the session context response, and this CN tunnel information is used to establish the N3 tunnel. For a PDU session that deactivates or releases the user plane resources, the session context response sent by the SMF to the AMF does not carry the CN tunnel information, and then the SMF releases the PDU session. S508 can be executed at any time after the SMF receives the N4 session modification response.

[0171] At S509, the AMF sends an N2 path switch request acknowledgment (N2 Path Switch Request Ack) to the target cell.

[0172] The N2 path switch request confirmation may include contents such as N2 SM Information, Failed PDU Sessions, and UE Radio Capability ID. After receiving the session context response, the AMF may write the CN tunnel information therein as part of the N2 SM Information into the N2 path switch request confirmation and send it to the target cell.

[0173] S510, the target cell instructs the source cell to release resources.

[0174] The target cell may indicate successful handover to the source cell, triggering the source cell to release resources.

[0175] S511, the terminal executes the registration process.

[0176] If the conditions for mobility registration update are met, the terminal may initiate the mobility registration update process.

[0177] 1.2. Cell handover based on the N2 interface.

[0178] Due to new radio conditions or load balancing requirements, if the source cell fails to find the Xn interface of the target cell, or the source cell receives an error indication of Xn handover failure, or the source cell determines to trigger the cell handover process based on the N2 interface based on the learned dynamic information, the source cell may execute the cell handover process based on the N2 interface.

[0179] Compared with the cell handover process based on the Xn interface, in the cell handover process based on the N2 interface, there may be no Xn interface between the base stations of the target cell and the source cell, and some terminal context information transmission can be completed through the AMF; since the AMF managing the base station of the target cell and the AMF managing the base station of the source cell may be different, this process may also involve the selection and handover of the target AMF. The N2 handover can be divided into two stages:

[0180] Preparation stage:

[0181] Before the source cell determines to initiate the handover process, the source cell may send RRC configuration information to the terminal and send a list of cells for which the terminal needs to measure the signal quality. This list of cells may be an allow-list indicating cells that can be reselected (which can be understood as cells to which handover can be performed subsequently), or this list of cells may be an exclude-list, where the exclude-list indicates cells to which the terminal cannot perform cell reselection (which can be understood as cells to which the terminal will not be handed over subsequently). The terminal may perform signal quality measurements on the cells in the allow-list or on the cells outside the exclude-list. The terminal periodically generates a measurement report and sends it to the source cell. The source cell may initiate the handover process based on the measurement report. For example, when the signal quality of the source cell is lower than a certain threshold and the signal quality of a neighboring cell is better, such as higher than a certain specific threshold, the source cell determines to hand over the terminal to that neighboring cell.

[0182] After the source cell initiates the handover process, the main work completed in the preparation stage is the resource allocation of the target-side core network and radio network. For example: the SMF selects a new target UPF as the intermediate UPF, an N9 interface tunnel is established between the target UPF and the PSA-UPF, the target cell allocates radio resources, an N3 interface tunnel is established between the target cell and the target UPF, and a UE context is established on the target AMF, etc.

[0183] Execution stage: The source cell notifies the terminal of the handover. After the terminal hands over, the target cell notifies the target AMF, the target AMF notifies the source AMF, and the source AMF releases the sessions for which handover is rejected. The target SMF notifies the PSA-UPF of the information of the target UPF to complete the handover of the downlink data channel. After the handover is completed, the subsequent processes may also include a registration process, releasing the resources on the source UPF and the source cell, and releasing the resources of the indirect data forwarding tunnel, etc.

[0184] 1.3. Registration process for 3GPP access types.

[0185] As Figure 6 shown, the registration process for 3GPP access types includes the following.

[0186] S601, the terminal sends a Registration Request to the RAN.

[0187] The terminal can send an access network (AN) message to the RAN (equivalent to a cell). The AN message includes AN parameters and a registration request. The AN parameters can be used by the RAN for AMF selection. The registration request includes a registration type and terminal identification information. Among them, the terminal identification information can include a subscription concealed identifier (SUCI) or a 5G global unique temporary UE identifier (5G-GUTI).

[0188] S602, the RAN selects a suitable AMF.

[0189] S603, the RAN sends the registration request sent by the terminal to the AMF.

[0190] S604, the AMF selects a suitable AUSF for authentication and other security processes.

[0191] The terminal, AMF, AUSF, and UDM can complete authentication and other security processes through interaction.

[0192] S605, the AMF interacts with the UDM to complete the subscription process.

[0193] After the mutual authentication between the terminal and the network is successful, the AMF interacts with the UDM to obtain the subscription data of the terminal.

[0194] S606, the AMF sends a Registration Accept message to the RAN.

[0195] The AMF can send a registration acceptance message to the RAN through an N2 message. The N2 message can also include a non-access stratum (NAS) message sent by the AMF to the terminal.

[0196] S607, the RAN forwards the registration acceptance message of the AMF to the terminal.

[0197] 2. Dual connection.

[0198] In an embodiment of the present application, dual connectivity refers to a communication mode in which a terminal establishes at least two RRC connections with at least two RANs. Dual connectivity can also be referred to as multi-connectivity, dual 3GPP access, multi-3GPP access, dual 3GPP access type, multiple 3GPP access type, dual 3GPP radio access technology, multiple 3GPP radio access technology, dual steer, multiple steer, dual radio capability, multiple radio capability, same access type, same radio access technology, or same access network, etc.

[0199] Figure 7 It is a schematic diagram of a dual connectivity scenario provided by an embodiment of the present application. The terminal has established two RRC connections with RAN1 and RAN2 respectively. Optionally, the terminal can also establish communication connections with more RANs, and the communication connection can be an RRC connection or a non-RRC connection.

[0200] Figure 8 It is a schematic diagram of another dual connectivity scenario provided by an embodiment of the present application. The terminal has established two RRC connections with RAN1 and RAN2 respectively, and the terminal has established user plane connections with UPF1 and UPF2 respectively. There may or may not be a communication interface between UPF1 and UPF2.

[0201] In a dual connectivity scenario, the terminal can actively establish multiple RRC connections with multiple RANs and send or receive data through these multiple RRC connections. If the signal quality of one of the RRC connections is poor, the terminal can use other RRC connections for communication. Taking Figure 7 as an example, after the terminal has established two RRC connections with RAN1 and RAN2 respectively, if the signal quality of the RRC connection between the terminal and RAN1 is poor, the terminal can disconnect the RRC connection with RAN1 and use the RRC connection with RAN2 to transmit data; or, the terminal can stop using the RRC connection of RAN1 to transmit data and instead use the RRC connection of RAN2 to transmit data. Among them, the RRC connection of RAN1 can be retained, and the signaling can continue to be transmitted through the RRC connection of RAN1, or the signaling can be transmitted through the RRC connection of RAN2. These situations can be referred to as dual connectivity handover.

[0202] 3. Equivalent PLMN

[0203] An equivalent PLMN (EPLMN) can also be referred to as an equivalent PLMN. The cell corresponding to the EPLMN has some identical information with the cell corresponding to the registered PLMN (RPLMN), such as frequency points, scrambling codes, etc. These information may be stored in the terminal, which helps to speed up the cell selection speed. For cell handover, the terminal can directly hand over to the cell corresponding to the equivalent PLMN (or the same PLMN) in the RRC connected state without disconnecting the RRC connection to perform network selection.

[0204] The effects of the above-mentioned dual-connection handover and cell handover are basically the same. Since these two mechanisms are not mutually exclusive, in some scenarios, the terminal can hand over to the target cell either through cell handover or through dual-connection handover. If the terminal uses both handover methods simultaneously, conflicts may occur between the two handover methods, resulting in some problems.

[0205] For example, after the terminal hands over to the target cell through dual-connection handover and establishes an RRC connection with the target cell, if the terminal then hands over to the target cell through cell handover, the terminal will attempt to establish another RRC connection with the target cell. If the target cell does not support establishing two RRC connections with the same terminal, it will cause the cell handover to fail. Even if the target cell supports establishing two RRC connections with the same terminal, there may be problems such as signal interference between the two RRC connections. In addition, if the target cells selected by the dual-connection handover and the cell handover are inconsistent, the terminal may release the connection with one of the target cells. In this case, the terminal establishes connections with multiple target cells respectively during the handover process, resulting in unnecessary signaling overhead.

[0206] The following introduces the communication method provided by the embodiments of the present application.

[0207] As Figure 9 shown, method 900 includes the following.

[0208] S910, the terminal sends a first piece of information to the access network device, indicating that the terminal supports multiple handover methods, and the multiple handover methods include a first handover method and a second handover method.

[0209] Correspondingly, the access network device receives the first piece of information from the terminal.

[0210] Note that, with the development of technology, most terminals may support multiple handover methods. The access network device and the core network device may default that the terminal supports multiple handover methods, so the terminal does not need to send the first information. Therefore, in various embodiments of the present application, the steps related to the first information (e.g., S910 and S920) are optional steps.

[0211] In various embodiments of the present application, the access network device may be the RAN node described above, and the RAN node provides the function of the source cell. The communication connection between the terminal and the source cell may be referred to as the first path, and the first path may also include other connections, such as one or more of the connections between the access network device and the core network device, the connections between different core network devices, and the connections between the core network device and the DN.

[0212] The first information may be carried in an AN message or an NAS message, and the embodiments of the present application do not limit the message carrying the first information.

[0213] The first handover method may be a handover method based on cell handover, and the second handover method may be a handover method based on dual connectivity; or, the first handover method may be a handover method based on dual connectivity, and the second handover method may be a handover method based on cell handover. For ease of description, the former case is used as an example for illustration below.

[0214] In various embodiments of the present application, the first handover method and the second handover method are used to switch paths, and the path may also be referred to as a connection, a communication connection, a data connection, a user plane connection, a channel, a data channel, a user plane channel, a tunnel, a channel, a flow, or a data flow, etc. The first handover method may also be referred to as a first change method, or a first transfer method, etc. The second handover method may also be referred to as a second change method, or a second transfer method, etc.

[0215] Optionally, "the first information indicates that the terminal supports multiple handover methods, and the multiple handover methods include a first handover method and a second handover method" may be alternatively expressed as:

[0216] The first information indicates that the terminal has multiple handover capabilities; or,

[0217] The first information indicates that the terminal supports the second handover method, where the second handover method is a handover method based on dual connectivity; or,

[0218] The first information indicates that the terminal has the ability of the second handover method, where the second handover method is a handover method based on dual connectivity.

[0219] Since the first handover method is a relatively popular technology, if the first information indicates that the terminal supports the second handover method, the access network device and the core network device may understand that the terminal supports multiple handover methods.

[0220] The first piece of information may be a dedicated bit. For example, when the value of this bit is 1, it indicates that the terminal supports multiple handover methods, or indicates that the terminal supports the second handover method; when the value of this bit is 0, it indicates that the terminal does not support multiple handover methods, or indicates that the terminal does not support the second handover method.

[0221] The first piece of information can also be implemented by multiplexing other information. For example, the pilot sequence sent by the terminal to the access network device includes sequence 1 and sequence 2. The terminal can indicate that the terminal supports multiple handover methods (or the second handover method) by sending sequence 1, and the terminal can indicate that the terminal does not support multiple handover methods (or the second handover method) by sending sequence 2.

[0222] Embodiments of the present application do not limit the specific form of the first piece of information.

[0223] In addition, the terminal can send the first piece of information during initial access, or can send the first piece of information in the RRC connected state or the RRC idle state, or can also send the first piece of information in other cases. Embodiments of the present application do not limit the specific timing for the terminal to send the first piece of information.

[0224] S920, the access network device sends the first piece of information to the core network device.

[0225] Correspondingly, the core network device receives the first piece of information from the access network device. This core network device is, for example, an AMF. After receiving the first piece of information, if the access network device determines that the terminal supports multiple handover methods, the access network device can select an AMF that supports multiple handover methods and send the first piece of information to this AMF.

[0226] The access network device can send the first piece of information to the AMF through a next generation application protocol (NGAP) message or an N2 message, or can also send the first piece of information to the AMF in other ways. Embodiments of the present application do not limit the specific manner for the access network device to send the first piece of information.

[0227] It should be noted that the first piece of information sent by the terminal and the first piece of information sent by the access network device may have different forms. For example, the first piece of information sent by the terminal is carried in message A, and the first piece of information sent by the access network device is carried in message B; or, the first piece of information sent by the terminal multiplexes other information, and the first piece of information sent by the access network device is a dedicated bit.

[0228] S930, the core network device sends permission information to the access network device. The permission information indicates that the terminal is allowed to perform multiple handover methods, or the permission information indicates that the terminal is allowed to perform the second handover method.

[0229] Accordingly, the access network device receives permission information from the core network device.

[0230] In various embodiments of the present application, the permission information may be referred to as: authorization information, indication information, policy information, support information, etc. The embodiments of the present application do not limit the specific name of the permission information.

[0231] The permission information indicates that the terminal is allowed to perform multiple handover methods, which can also be expressed as:

[0232] The permission information indicates that the network supports multiple handover methods; or, the permission information authorizes the terminal to perform multiple handover methods.

[0233] The permission information indicates that the terminal is allowed to perform the second handover method, which can also be expressed as:

[0234] The permission information indicates that the network supports the second handover method; or, the permission information authorizes the terminal to perform the second handover method.

[0235] The core network device further includes, for example, a UDM. After the AMF forwards the first information to the UDM, the UDM determines whether to allow the terminal to perform multiple handover methods, or the UDM determines whether to allow the terminal to perform the second handover method. For example, the UDM may determine whether to allow the terminal to perform the second handover method according to the subscription data of the terminal. If the UDM determines to allow the terminal to perform multiple handover methods, it may send permission information to the AMF, and the AMF may forward the permission information to the access network device.

[0236] The core network device may send the permission information to the access network device in an explicit or implicit manner. For example, when indicating in an explicit manner, the permission information may be a dedicated bit, and the value of this bit is 1, indicating that the terminal is allowed to perform multiple handover methods, or the terminal is allowed to perform the second handover method; when indicating in an implicit manner, the permission information may be an empty set, and this empty set is the cell set or PLMN set corresponding to the first handover method. Optionally, the core network device may also send the dedicated bit and the empty set to the access network device at the same time.

[0237] In a possible implementation, the permission information is optional information; for example, when the terminal does not need to provide the first information, the core network device may consider that the terminal is allowed to perform the first handover method and the second handover method. At this time, the core network device does not need to send permission information to the access network device, that is, it is default that the terminal can perform the first handover method and the second handover method.

[0238] In the case where both the core network device and the terminal support multiple handover methods, both the core network device and the terminal can decide to preferentially perform the first handover method or the second handover method. Below, these two cases are introduced separately.

[0239] Case 1: The core network device decides to preferentially execute the first handover method or the second handover method.

[0240] If the core network device decides to preferentially execute the second handover method, it can carry some information indicating the access network device through the permission information. For example, the permission information includes at least one of the following information:

[0241] The fifth information, indicating that the access network device does not execute the first handover method;

[0242] The sixth information, indicating that the access network device executes the second handover method;

[0243] The first PLMN set, where the PLMNs in the first PLMN set are not equivalent to the PLMN of the first cell, and the first cell is the cell on the first path;

[0244] The seventh information, indicating that the priority of the first handover method is lower than the priority of the second handover method.

[0245] Indicating the priority of the access technology type of the first handover method and / or the priority of the access technology type of the second handover method.

[0246] In some cases, when the core network device determines not to execute the first handover method, the core network device can indicate to the access network device not to execute the first handover method through one or more pieces of information in the permission information. Among them, the fifth information and the sixth information can be dedicated bit positions, the first PLMN set can be the PLMN set obtained by removing the equivalent PLMN from the mobility restriction list (MRL), and the seventh information can be the RAT or frequency selection priority (RFSP) of the first handover method and the second handover method. The access network device can, according to the permission information, instruct the terminal not to perform operations related to the first handover method, or remove the cells in the allow-list that support the first handover method (such as the cells corresponding to the equivalent PLMN), or add the cells in the exclude-list that support the first handover method (such as the cells corresponding to the equivalent PLMN), thereby avoiding the conflict problem caused by the terminal simultaneously executing the first handover method and the second handover method.

[0247] If the core network device decides to preferentially execute the first handover method, it can carry some information indicating the access network device through the permission information. For example, the permission information includes at least one of the following information:

[0248] Information indicating that the access network device executes the first handover method (such as a dedicated bit position);

[0249] Information indicating that the access network device does not perform the second handover method (e.g., a dedicated bit);

[0250] The second PLMN set, where the PLMNs in the second PLMN set are equivalent to the PLMN of the first cell, and the first cell is the cell on the first path (e.g., the PLMN set obtained by removing non - equivalent PLMNs from the MRL);

[0251] Information indicating that the priority of the first handover method is higher than the priority of the second handover method (e.g., the RFSP of the first handover method and the second handover method).

[0252] Indicating the priority of the access technology type of the first handover method and / or the priority of the access technology type of the second handover method.

[0253] In some cases, for example, when the access network device is a satellite, if the core network device determines not to perform the second handover method, the core network device can indicate to the access network device not to perform the second handover method through one or more pieces of information in the permission information. The access network device can, according to the permission information, instruct the terminal not to perform operations related to the second handover method, or remove the cells in the allow - list that support the second handover method (e.g., cells corresponding to non - equivalent PLMNs), or add the cells in the exclude - list that support the second handover method (e.g., cells corresponding to non - equivalent PLMNs), so as to avoid the conflict problem caused by the terminal performing both the first handover method and the second handover method simultaneously.

[0254] Optionally, if the core network device decides to give priority to the first handover method, the core network device can also send to the terminal the PLMN set containing equivalent PLMNs, and the core network device sends information to the terminal, which indicates that when the terminal performs the second handover method, it only establishes a connection with the access network device corresponding to the PLMN outside the equivalent PLMNs.

[0255] Optionally, the core network device can also directly send the PLMN sets suitable for different handover methods to the terminal, and the terminal selects the second cell according to the PLMN sets. This method will be introduced in detail below.

[0256] Case 2: The terminal decides to give priority to the first handover method or the second handover method.

[0257] In this case, the core network device may not indicate to the access network device which handover method to give priority to. The access network device can indicate the cells suitable for different handover methods to the terminal, and the terminal decides which handover method to give priority to.

[0258] For example, when the terminal decides to preferentially execute the first handover method, it can perform signal measurement in a cell that supports the first handover method. The cell that supports the first handover method is, for example, the cell corresponding to the first set described below, or a cell outside the cell corresponding to the second set. When the terminal decides to preferentially execute the second handover method, it can perform signal measurement in a cell that supports the second handover method. The cell that supports the second handover method is, for example, the cell corresponding to the second set described below, or a cell outside the cell corresponding to the first set.

[0259] When the terminal decides to preferentially execute the second handover method, the terminal can also modify the actual signal measurement report to avoid the access network device triggering the first handover method. This method will be introduced in detail below.

[0260] It should be noted that in Case 1 and Case 2, preferentially executing the first handover method or the second handover method can be determined by the core network device or the terminal according to the actual situation. For example, if the access network device or the core network device only supports one handover method (such as the first handover method), the core network device or the terminal can decide to preferentially execute the first handover method; or for another example, if the power consumption of one handover method (such as the second handover method) is greater than that of another handover method (such as the first handover method), the core network device or the terminal can decide to preferentially execute the first handover method. The embodiments of the present application do not limit the conditions for preferentially executing the first handover method or the second handover method.

[0261] After receiving the permission information, the access network device can perform the following steps.

[0262] S940, the access network device sends the second information to the terminal. The second information includes the first set and / or the second set. The first set indicates the cells that support the first handover method, and the second set indicates the cells that support the second handover method.

[0263] Correspondingly, the terminal receives the second information from the access network device.

[0264] If the core network device sends the first set and / or the second set to the access network device, the access network device can forward the first set and / or the second set to the terminal. If the core network device does not send the first set and / or the second set to the access network device, the access network device can determine the first set and / or the second set according to the permission information and send the first set and / or the second set to the terminal.

[0265] Optionally, if the first set and / or the second set is a cell set, then the PLMN corresponding to the cells in the first cell set is equivalent to the PLMN of the first cell, or the PLMN corresponding to the cells in the first cell set is the same as the PLMN of the first cell, or the PLMN corresponding to the cells in the second cell set is a non-equivalent PLMN to the PLMN of the first cell, or the PLMN corresponding to the cells in the second cell set is different from the PLMN of the first cell; where the first cell is the cell on the first path (e.g., the source cell); or the cells in the first cell set are the cells corresponding to the terrestrial network (TN), and the cells in the second cell set are the cells corresponding to the non-terrestrial network (NTN); or the access technology type of the cells in the first cell set is the same as the access technology type of the first cell, and the access technology type of the cells in the second cell set is different from the access technology type of the first cell.

[0266] Optionally, if the first set and / or the second set is a PLMN set, then the PLMN in the first PLMN set is equivalent to the PLMN of the first cell, or the PLMN in the first PLMN set contains the PLMN of the first cell, or the PLMN in the second PLMN set is not equivalent to the PLMN of the first cell, or the PLMN in the second PLMN set does not contain the PLMN of the first cell; where the first cell is the cell on the first path (e.g., the source cell).

[0267] For cell handover, the terminal can directly hand over to the cell corresponding to the equivalent PLMN (or the same PLMN) in the RRC connected state without disconnecting the RRC connection to perform network selection. Therefore, configuring the first set as an equivalent PLMN set (or the same PLMN set), or configuring the first set as a cell set corresponding to the equivalent PLMN (or the same PLMN) is beneficial to the path handover method based on cell handover.

[0268] S950, the terminal performs handover according to the second information.

[0269] The terminal can determine to switch the first path to the second path through the first handover method or the second handover method according to the second information. The second path includes the connection between the terminal and the second cell. When switching the first path to the second path through the first handover method, the second cell belongs to the cells indicated by the first set, or the second cell does not belong to the cells indicated by the second set; or when switching the first path to the second path through the second handover method, the second cell belongs to the cells indicated by the second set, or the second cell does not belong to the cells indicated by the first set.

[0270] It should be noted that the second cell may be a cell supporting the first handover method or the second handover method, or the second cell may be a cell supporting both the first handover method and the second handover method. When the second cell supports both the first handover method and the second handover method, and when the second information includes a first set and a second set, the cells indicated by the first set and the cells indicated by the second set may both include the second cell.

[0271] The first set and the second set may be two lists (e.g., allow-list and exclude-list), or two groups, or other forms of information sets. The embodiments of the present application do not limit the specific forms of the first set and the second set.

[0272] For example, the second information includes a first set, and the first set is a set of cells supporting the first handover method. If the terminal determines to switch the first path to the second path through the first handover method, the terminal may measure the cells in the first set and send a measurement report to the first cell, so that the first cell can trigger the first handover method; if the terminal determines to switch the first path to the second path through the second handover method, the terminal may not measure the cells in the first set, but select a cell outside the first set as the second cell, establish an RRC connection with the second cell, and switch the first path to the second path through the second handover method.

[0273] Another example is that the second information includes a second set, and the second set is a set of cells supporting the second handover method. If the terminal determines to switch the first path to the second path through the first handover method, the terminal may measure the cells outside the second set and send a measurement report to the first cell, so that the first cell can trigger the first handover method; if the terminal determines to switch the first path to the second path through the second handover method, the terminal may not measure the cells outside the second set, but select a cell in the second set as the second cell, establish an RRC connection with the second cell, and switch the first path to the second path through the second handover method.

[0274] For another example, the second information includes a first set and a second set. The first set is a set of cells that support the first handover method, and the second set is a set of cells that support the second handover method. If the terminal determines to switch the first path to the second path by the first handover method, the terminal can measure the cells in the first set, or measure the cells outside the first set and the second set, and send a measurement report to the first cell, so that the first cell can trigger the first handover method. If the terminal determines to switch the first path to the second path by the second handover method, the terminal does not need to measure the cells in the first set. The terminal can select a cell from the second set and the cells outside the first set and the second set as the second cell, establish an RRC connection with the second cell, and switch the first path to the second path by the second handover method.

[0275] In a possible implementation, if the terminal determines to switch the first path to the second path by the second handover method, the terminal can report the cell signal quality measurement reports of the cells in the first set to the first cell, where the reported cell signal quality measurement results do not meet the conditions for executing the first handover method, so as to prevent the first cell from triggering the first handover method. Exemplarily, the terminal can modify the cell signal quality measurement results of the cells in the first set, adjust the value corresponding to the signal quality in the measurement results to a value lower than the threshold for triggering the execution of the first handover method, and report the modified measurement results to the first cell, so as to prevent the first cell from triggering the first handover method. Exemplarily, the terminal can directly generate the cell signal quality measurement results of the cells in the first set without performing cell measurement. The value corresponding to the signal quality in the measurement results is lower than the threshold for triggering the execution of the first handover method, and report the measurement results to the first cell, so as to prevent the first cell from triggering the first handover method.

[0276] As can be seen from the above, the applicable handover methods of different cells may be different. The first set and / or the second set indicate the cells corresponding to different handover methods. After determining the handover method, the terminal can select the second cell according to the second information. If it is determined to switch the path by the first handover method, the second cell can be selected from the cells that support the first handover method, or the selection of cells that support the second handover method can be avoided. If it is determined to switch the path by the second handover method, the second cell can be selected from the cells that support the second handover method, or the selection of cells that support the first handover method can be avoided. Thus, the problem caused by the incompatibility between the selected cell and the determined handover method can be avoided.

[0277] It should be noted that when the terminal switches from the first path to the second path, it can be to disconnect the first path (i.e., delete the parameters related to the first path), or to deactivate the first path (i.e., retain the parameters related to the first path but no longer use the first path to transmit data and signaling), or to switch the data transmission to the second path and continue to use the first path to transmit signaling, or to switch both the data transmission and the signaling transmission to the second path.

[0278] Next, several methods provided by the embodiments of the present application will be introduced.

[0279] Figure 10 It is another communication method provided by the embodiments of the present application. In this method, the core network decides to preferentially perform dual-connection handover. As Figure 10 shown, method 1000 includes the following.

[0280] S1001, the terminal sends a registration request message to RAN1.

[0281] The registration request message can be carried in the AN message. The registration request message can include a terminal identifier (such as SUCI), a registration type, capability information, etc. The registration type can be an initial registration, a mobility registration update, etc. The capability information can include one or more of the following: DualSteer Indication, support for dual connection, or dual radio capability (such as Dual Radio Capability), or multiple radio capabilities (such as Multiple RadioCapability). This capability information is to let AMF1 know that the terminal has the ability to establish a dual connection, so that AMF1 can determine whether to allow the terminal to actively establish a dual connection based on network capabilities and / or terminal subscription status. The DualSteer Indication can be carried not only in the capability information but also in the AN parameters in the AN message.

[0282] As described above, DualSteer can be replaced by concepts such as dual connection. Therefore, the DualSteer Indication can also be referred to as: Dual Connection Indication, Multi-Connection Indication, Dual 3GPP Access Indication, Multi-3GPP Access Indication, Dual 3GPP Access Type Indication, Multi-3GPP Access Type Indication, Dual 3GPP Radio Access Technology Indication, Multi-3GPP Radio Access Technology Indication, Multi-Steer Indication, Dual Radio Capability Indication, Multiple Radio Capability Indication, Same Access Type Indication, Same Radio Access Technology Indication, or Same Access Network Indication, etc. In other embodiments of the present application, the DualSteer Indication can also be replaced by concepts such as Dual Connection Indication.

[0283] An example of a cell with an RRC connection between RAN1 and a terminal, i.e., the first cell, includes a path of the first cell, i.e., the first path, and an example of a dual-split indication, i.e., the first information.

[0284] S1002, RAN1 sends a registration request message to AMF1.

[0285] RAN1 receives the AN message sent by the terminal and selects an AMF according to the AN message. For example, when the AN message includes a dual-split indication, RAN1 selects an AMF that supports managing a "terminal with dual radio capabilities / multi-radio capabilities" according to this indication information. An AMF that supports managing a "terminal with dual radio capabilities / multi-radio capabilities" can be understood as an AMF that supports dual registration / multi-registration (i.e., the terminal can perform dual registration or multi-registration through the same access type). In various embodiments of the present application, "supporting dual registration / multi-registration" can be understood as: supporting dual registration management / multi-registration management, or, supporting dual registration / multi-registration under the same access type, or, supporting dual registration / multi-registration under the same access technology.

[0286] If there is no dual-split indication in the AN message, RAN1 can select AMF1 according to information such as slices and PLMN ID.

[0287] After determining AMF1, RAN1 sends a registration request message from the terminal to AMF1. For example, RAN1 sends a registration request message to AMF1 through an NGAP or N2 message. In one possible implementation, RAN1 can send capability information to AMF1, and the capability information includes a dual-split indication.

[0288] S1003, AMF1 triggers an authentication and security process (e.g., authentication and security procedure).

[0289] S1003 is an optional step. After successful authentication, AMF1 can send a registration request to the UDM, and this registration request is used for AMF1 to register with the UDM as the AMF for serving the terminal.

[0290] S1004, AMF1 sends a subscribed data request message to the UDM.

[0291] AMF1 can request the UDM to obtain the subscribed information of the terminal. In one possible implementation, AMF1 can send a subscribed data request message (e.g., Nudm_SDM_Get Request) to the UDM, and this request message can include capability information, and the capability information includes a dual-split indication, indicating that the terminal supports dual radio capabilities / multi-radio capabilities.

[0292] S1005. The UDM sends a subscription data response message to AMF1.

[0293] The UDM can determine whether to allow the terminal to perform dual connectivity, or whether to authorize the terminal to perform dual connectivity, or whether the network supports dual multi-radio capabilities, or whether the network supports multi-radio capabilities. In one possible implementation, the UDM can determine whether to allow / authorize the terminal to use dual connectivity based on the terminal's subscription data, and / or the UDM can determine whether to support dual radio connectivity / multi-radio connectivity based on the network capabilities (e.g., the UDM can configure this capability). If the UDM allows / authorizes the terminal to use dual connectivity, or if the UDM supports dual radio connectivity / multi-radio connectivity, the UDM can send a subscription data response message (e.g., Nudm_SDM_Get Response) to the AMF. This message can include permission information, which indicates that the terminal is allowed to perform multiple handover methods. The multiple handover methods include a first handover method and a second handover method; or the permission information indicates that the terminal is allowed to perform the second handover method. For example, the permission information can be called DualSteer Authorised or DualSteer Supported, indicating whether to allow / authorize / support the terminal to perform dual connectivity, or dual radio connectivity capabilities / multi-radio connectivity capabilities.

[0294] S1006. AMF1 sends an initial context setup request message to RAN1.

[0295] The initial context setup request message (Initial Context Setup Request) can include some information indicating that RAN1 does not perform cell handover, or information indicating that RAN1 does not perform cell handover under specific conditions. The information carried in the initial context setup request message can be regarded as some examples of permission information.

[0296] For example, the permission information can include at least one of the following information:

[0297] Information indicating that RAN1 performs dual connectivity handover (an example of the sixth information);

[0298] Information indicating that RAN1 does not perform cell handover (an example of the fifth information);

[0299] A mobility restriction list (MRL) that does not contain equivalent PLMN information, that is, the PLMNs in this list are not equivalent to the PLMN of the first cell, such that RAN1 does not trigger the UE to switch to the cell corresponding to the equivalent PLMN through cell handover; or, an MRL that contains equivalent PLMN information and indication information, where the indication information instructs RAN1 to place the cell corresponding to the PLMN in the MRL in the exclude-list or remove it from the allow-list;

[0300] The RFSP for cell handover and the RFSP for dual-connectivity handover (an example of the seventh information), where the RFSP for cell handover is higher than the RFSP for dual-connectivity handover. In another possible implementation, among the RFSPs for cell handover, the high-priority access technology type is different from the high-priority access technology type for performing dual-connectivity handover. Exemplarily, among the RFSPs for cell handover, the high-priority access technology type is a terrestrial network (TN), while the high-priority access technology type corresponding to the cell for performing dual-connectivity handover is a non-terrestrial network (NTN), such as a satellite access technology.

[0301] The above information instructing RAN1 to perform dual-connectivity handover, information instructing RAN1 not to perform cell handover, an MRL that does not contain equivalent PLMN information, an MRL that contains equivalent PLMN information and indication information, or the RFSP for cell handover and the RFSP for dual-connectivity handover are all examples of permission information.

[0302] Based on one or more pieces of information in the initial context setup request message, RAN1 does not instruct the UE to perform signal measurement (i.e., does not instruct the UE to execute the cell handover procedure), or instructs the UE not to perform signal measurement, such as not including any cells in the allow-list sent to the UE; or adding cell information for not performing cell handover (such as information about the cell corresponding to the equivalent PLMN) to the exclude-list sent to the UE; or removing cell information for not performing cell handover (such as information about the cell corresponding to the equivalent PLMN) from the allow-list.

[0303] S1007, RAN1 sends an RRC reconfiguration message to the UE.

[0304] After determining not to perform a cell handover through an initial context setup request message, RAN1 can update the configuration information for the terminal through an RRC reconfiguration message. The updated configuration information may include: 1) an exclude-list (this list indicates that the terminal should not handover to the cells in this list), and the exclude-list may include information about cells not supported by RAN1 (such as neighboring cells), so that the terminal will not handover to cells not supported by RAN1, achieving the effect of not handing over to other RANs; or it may include a list of cells of equivalent PLMNs (such as neighboring cells), so that the terminal will not handover to cells within non-equivalent PLMNs, achieving the effect of not handing over to RANs of other PLMNs. Whether to include cells of the same PLMN (such as neighboring cells) in the exclude-list may depend on the network policy. For example, when the network only allows the terminal to establish a connection with RANs of different PLMNs through dual connectivity, the cell handover mechanism within the same PLMN can be normally executed. However, for cell handovers across PLMNs, there may be conflicts with dual-connectivity handovers. Therefore, only the conflicts in the cross-PLMN scenario need to be resolved. If the network policy is to allow the terminal to initiate dual connectivity at any time, there will be similar problems within the same PLMN. Therefore, cell handovers can be restricted to cells within the same RAN, or even no cell handovers are performed at all, to avoid conflicts. 2) an allow-list, which indicates the cells to which the terminal can handover. For example, when RAN1 removes all cells from the allow-list, it can enable the terminal not to perform any cell handovers; when RAN1 removes cells of other RANs from the allow-list, it can enable the terminal to perform cell handovers only within the station of RAN1 and not perform cross-station cell handovers; when RAN1 removes cells corresponding to other PLMNs from the allow-list, it can enable the terminal to perform cell handovers only within the PLMN and not perform cross-PLMN cell handovers. In one possible implementation, handover can be understood as reselection.

[0305] The exclude-list and the allow-list can exist simultaneously or only one of them can exist. The exclude-list and / or the allow-list can be regarded as an example of the second information.

[0306] S1008, RAN1 sends an initial context setup response message to AMF1.

[0307] The initial context setup response (Initial Context Setup Response) message indicates to AMF1 that RAN1 has established the context. Optionally, the initial context setup response message may further include information indicating that the handover mode configuration of the terminal has been updated, and this information can be regarded as an example of the eighth information.

[0308] S1009. AMF1 sends a registration acceptance message to the terminal.

[0309] Optionally, the registration acceptance message may include indication information, such as DualSteer Supported Indication or DualSteer Authorized Indication. Optionally, the registration acceptance message or the registration acceptance message containing indication information may be triggered by the registration request message in S1002. That is to say, the indication information in the registration acceptance message may be triggered by the dual-steer indication in S1002. The DualSteer Supported Indication or the DualSteer Authorized Indication is an example of the third information, where the third information indicates that the terminal is allowed to perform multiple handover methods, and the multiple handover methods include the first handover method and the second handover method.

[0310] S1010. The terminal establishes a connection with RAN2.

[0311] The terminal determines that it can perform dual-connection handover according to the indication information in the registration acceptance message. The terminal can establish a connection with RAN2 based on certain criteria and initiate a registration process (similar to S1001 - S1009). After establishing a connection with RAN2, the terminal can switch from the first path (including the path of RAN1) to the second path (including the path of RAN2). For example, after the second path is established and the signal quality of the first path deteriorates (e.g., below the signal quality threshold), the terminal can switch from the first path to the second path.

[0312] Figure 11 This is another communication method provided by the embodiments of the present application. In this method, the terminal decides to preferentially perform dual-connection handover. As Figure 11 shown, method 1100 includes the following.

[0313] S1101. The terminal sends a registration request message to RAN1.

[0314] The registration request message can be carried in the AN message. The registration request message can include terminal identification (e.g., SUCI), registration type, capability information, etc. The registration type can be initial registration, mobility registration update, etc. The capability information can include one or more of the following information: DualSteer Indication, support for dual connectivity, or dual radio capability (e.g., Dual Radio Capability), or multiple radio capabilities (e.g., Multiple RadioCapability). This capability information is for the AMF1 to know that the terminal has the ability to establish a dual connection, so that the AMF1 can determine whether to allow the terminal to actively establish a dual connection based on network capabilities and / or terminal subscription status. The DualSteer Indication can be carried not only in the capability information but also in the AN parameters in the AN message.

[0315] An example of the first cell with an RRC connection between RAN1 and the terminal is the first cell, the path including the first cell is the first path, and an example of the first information is the DualSteer Indication.

[0316] S1102, RAN1 sends a registration request message to AMF1.

[0317] RAN1 receives the AN message sent by the terminal and selects an AMF according to the AN message. For example, when the AN message includes the DualSteer Indication, RAN1 selects an AMF that supports managing "terminals with dual radio capabilities / multiple radio capabilities" according to this indication information. An AMF that supports managing "terminals with dual radio capabilities / multiple radio capabilities" can be understood as an AMF that supports dual registration / multiple registration (i.e., the terminal can perform dual registration or multiple registration through the same access type). In various embodiments of the present application, "supporting dual registration / multiple registration" can be understood as: supporting dual registration management / multiple registration management, or, supporting dual registration / multiple registration under the same access type, or, supporting dual registration / multiple registration under the same access technology.

[0318] If there is no DualSteer Indication in the AN message, RAN1 can select AMF1 according to information such as slices, PLMN ID, etc.

[0319] After determining AMF1, RAN1 sends the registration request message from the terminal to AMF1. For example, RAN1 sends the registration request message to AMF1 through the NGAP or N2 message. In one possible implementation, RAN1 can send capability information to AMF1, and this capability information includes the DualSteer Indication.

[0320] S1103, AMF1 triggers the authentication and security process (e.g., authentication and securityprocedure).

[0321] S1103 is an optional step. After successful authentication, AMF1 can send a registration request to the UDM, which is used for AMF1 to register with the UDM as the AMF of the serving terminal.

[0322] S1104, AMF1 sends a subscription data request message to the UDM.

[0323] AMF1 can request the UDM to obtain the subscription information of the terminal. In one possible implementation, AMF1 can send a subscription data request message (such as Nudm_SDM_Get Request) to the UDM, and the request message can include capability information, which includes a dual split indication indicating that the terminal supports dual radio capabilities / multi-radio capabilities.

[0324] S1105, the UDM sends a subscription data response message to AMF1.

[0325] The UDM can determine whether to allow the terminal to perform dual connection, or whether to authorize the terminal to perform dual connection, or whether the network supports dual multi-radio capabilities, or whether the network supports multi-radio capabilities. In one possible implementation, the UDM can determine whether to allow / authorize the terminal to use dual connection based on the subscription data of the terminal, and / or, the UDM can determine whether to support dual radio connection / multi-radio connection based on the network capabilities (for example, the UDM can configure this capability). If the UDM allows / authorizes the terminal to use dual connection, or if the UDM supports dual radio connection / multi-radio connection, then the UDM can send a subscription data response message (such as Nudm_SDM_Get Response) to the AMF, and the message can include DualSteer Authorised or DualSteer Supported, indicating whether to allow / authorize / support the terminal to perform dual connection, or dual radio connection capabilities / multi-radio connection capabilities. DualSteer Authorised or DualSteer Supported is an example of permission information.

[0326] S1106, AMF1 sends an initial context setup request message to RAN1.

[0327] The Initial Context Setup Request message may include indication information or authorization information that allows RAN1 to perform dual-connection handover or multiple handover methods, such as DualSteer AllowedIndication. Subsequently, RAN1 can determine whether to allow the terminal to perform dual-connection handover based on this information. For example, when the terminal subsequently wants to perform dual-connection handover, it can indicate to RAN1 that it wants to perform dual-connection handover, and RAN1 can determine to allow the UE to perform it based on the DualSteerAllowed Indication.

[0328] The above indication information or authorization information that allows RAN1 to perform dual-connection handover or multiple handover methods is an example of permission information.

[0329] S1107, RAN1 sends an Initial Context Setup Response message to AMF1.

[0330] The Initial Context Setup Response message indicates to AMF1 that RAN1 has established the context.

[0331] S1108, AMF1 sends a Registration Accept message to the terminal.

[0332] Optionally, the Registration Accept message may include indication information, such as DualSteer Supported Indication or DualSteerAuthorized Indication. Optionally, the Registration Accept message or the Registration Accept message containing indication information may be triggered by the Registration Request message in S1102. That is to say, the indication information in the Registration Accept message may be triggered by the dual-steer indication in S1102. The DualSteer Supported Indication or the DualSteerAuthorized Indication is an example of the third information, where the third information indicates that the terminal is allowed to perform multiple handover methods, and the multiple handover methods include the first handover method and the second handover method.

[0333] S1109, the terminal sends an RRC message to RAN1.

[0334] After receiving the Registration Accept message, the terminal determines that it can perform dual-connection handover. If the terminal decides to enable the mode of performing dual-connection handover, it can send the fourth information to RAN1 through the RRC message, such as the information indicating the activation of dual-steer, or the information indicating the initiation of dual-steer.

[0335] S1110, RAN1 sends an RRC reconfiguration message to the terminal.

[0336] The RRC reconfiguration message may include an exclude-list and / or an allow-list. The meanings of the exclude-list and the allow-list are the same as those in the exclude-list and the allow-list in method 1000, and will not be elaborated here.

[0337] The exclude-list and / or the allow-list can be regarded as an example of the second information.

[0338] S1111, the terminal establishes a connection with RAN2.

[0339] The terminal may determine to perform dual-connection handover according to the third information in S1108 or S1110. The terminal may establish a connection with RAN2 based on certain criteria and initiate a registration process (similar to S1101 - S1110). After establishing a connection with RAN2, the terminal may switch from the first path (including the path of RAN1) to the second path (including the path of RAN2). For example, after the second path is established, if the signal quality of the first path deteriorates (e.g., below the signal quality threshold), the terminal may switch from the first path to the second path.

[0340] Figure 12 This is another communication method provided by the embodiments of the present application. In this method, the terminal decides to preferentially perform dual-connection handover. As Figure 12 shown, method 1200 includes the following.

[0341] S1201, the terminal sends a registration request message to RAN1.

[0342] The registration request message may be carried in an AN message. The registration request message may include a terminal identifier (e.g., SUCI), a registration type, capability information, etc. The registration type may be an initial registration, a mobility registration update, etc. The capability information may include one or more of the following information: DualSteer Indication, support for dual-connection, or dual radio capability (e.g., Dual Radio Capability), or multiple radio capability (e.g., Multiple RadioCapability). This capability information is for AMF1 to know that the terminal has the ability to establish a dual-connection, so that AMF1 can determine whether to allow the terminal to actively establish a dual-connection based on network capabilities and / or terminal subscription conditions. The DualSteer Indication may be carried not only in the capability information but also in the AN parameters in the AN message.

[0343] An example of a cell with an RRC connection between RAN1 and a terminal, i.e., the first cell, includes a path of the first cell, i.e., the first path, and an example of a dual-split indication, i.e., the first information.

[0344] S1202, RAN1 sends a registration request message to AMF1.

[0345] RAN1 receives the AN message sent by the terminal and selects an AMF based on the AN message. For example, when the AN message includes a dual-split indication, RAN1 selects an AMF that supports managing "terminals with dual radio capabilities / multi-radio capabilities" according to this indication information. An AMF that supports managing "terminals with dual radio capabilities / multi-radio capabilities" can be understood as an AMF that supports dual registration / multi-registration (i.e., the terminal can perform dual registration or multi-registration through the same access type). In various embodiments of the present application, "supporting dual registration / multi-registration" can be understood as: supporting dual registration management / multi-registration management, or, supporting dual registration / multi-registration under the same access type, or, supporting dual registration / multi-registration under the same access technology.

[0346] If there is no dual-split indication in the AN message, RAN1 can select AMF1 based on information such as slices and PLMN ID.

[0347] After determining AMF1, RAN1 sends a registration request message from the terminal to AMF1. For example, RAN1 sends a registration request message to AMF1 through an NGAP or N2 message. In a possible implementation, RAN1 can send capability information to AMF1, and the capability information includes a dual-split indication.

[0348] S1203, AMF1 triggers an authentication and security process (e.g., authentication and security procedure).

[0349] S1203 is an optional step. After successful authentication, AMF1 can send a registration request to the UDM, and this registration request is used for AMF1 to register with the UDM as the AMF serving the terminal.

[0350] S1204, AMF1 sends a subscribed data request message to the UDM.

[0351] AMF1 can request the UDM to obtain the subscribed information of the terminal. In a possible implementation, AMF1 can send a subscribed data request message (e.g., Nudm_SDM_Get Request) to the UDM, and this request message can include capability information, and the capability information includes a dual-split indication, indicating that the terminal supports dual radio capabilities / multi-radio capabilities.

[0352] S1205, the UDM sends a subscription data response message to AMF1.

[0353] The UDM can determine whether to allow the terminal to perform dual connectivity, or whether to authorize the terminal to perform dual connectivity, or whether the network supports dual multi-radio capabilities, or whether the network supports multi-radio capabilities. In one possible implementation, the UDM can determine whether to allow / authorize the terminal to use dual connectivity based on the terminal's subscription data, and / or the UDM can determine whether to support dual radio connectivity / multi-radio connectivity based on the network capabilities (e.g., the UDM can configure this capability). If the UDM allows / authorizes the terminal to use dual connectivity, or if the UDM supports dual radio connectivity / multi-radio connectivity, the UDM can send a subscription data response message (e.g., Nudm_SDM_Get Response) to the AMF, and this message can include DualSteer Authorised or DualSteer Supported, indicating whether to allow / authorize / support the terminal to perform dual connectivity, or dual radio connectivity capability / multi-radio connectivity capability. DualSteer Authorised or DualSteer Supported is an example of permission information.

[0354] S1206, AMF1 sends an initial context setup request message to RAN1.

[0355] The initial context setup request message (Initial Context Setup Request) can include some indication information or authorization information that allows RAN1 to perform dual connectivity handover or multiple handover methods, such as DualSteer AllowedIndication. RAN1 can subsequently determine whether to allow the terminal to perform dual connectivity handover based on this information. For example, when the terminal subsequently wants to perform dual connectivity handover, it can indicate to RAN1 that it wants to do a dual connectivity handover, and RAN1 can determine to allow the UE to perform it based on DualSteerAllowed Indication.

[0356] The above indication information or authorization information that allows RAN1 to perform dual connectivity handover or multiple handover methods is an example of permission information.

[0357] S1207, RAN1 sends an initial context setup response message to AMF1.

[0358] The initial context setup response (Initial Context Setup Response) message indicates to AMF1 that RAN1 has established the context.

[0359] S1208, AMF1 sends a registration acceptance message to the terminal.

[0360] Optionally, the Registration Accept message may include DualSteer Supported Indication or DualSteer Authorized Indication. Optionally, the Registration Accept message or the Registration Accept message including the indication information may be triggered by the Registration Request message in S1202. In other words, the indication information in the Registration Accept message may be triggered by the DualSteer indication in S1202. The DualSteer Supported Indication or the DualSteer Authorized Indication is an example of the third information, where the third information indicates that the terminal is allowed to perform multiple handover methods, and the multiple handover methods include the first handover method and the second handover method.

[0361] Optionally, the Registration Accept message may include a PLMN list for DualSteer, indicating the PLMNs allowed to perform dual-connection handover. Optionally, equivalent PLMNs are removed from the list, or the terminal may autonomously remove equivalent PLMNs after receiving the list. The PLMN list for DualSteer is an example of the third information.

[0362] Optionally, the Registration Accept message may include a cell list for DualSteer, indicating the cells allowed to perform dual-connection handover. Optionally, cells corresponding to equivalent PLMNs are removed from the list, or the terminal may autonomously remove cells corresponding to equivalent PLMNs after receiving the list. The cell list for DualSteer is an example of the third information.

[0363] In S1209, the terminal sends a measurement report to RAN1.

[0364] After receiving the Registration Accept message, the terminal determines that dual-connection handover can be performed. If the terminal decides to perform dual-connection handover, it may perform any one of the following methods:

[0365] 1) Determine the cells allowed to perform dual-connection handover (e.g., cells corresponding to non-equivalent PLMNs) according to the PLMN list in S1208, perform signal measurement, and send a measurement report.

[0366] 2) Measure the signal quality of cells outside the allow-list, or measure the signal quality of cells within the exclude-list, and send a measurement report.

[0367] 3) Measure the signal quality of the cells within the allow-list, or measure the signal quality of the cells outside the exclude-list, modify the measurement report, and adjust the signal quality value in the measurement report from the first value to the second value, where the first value is greater than or equal to the signal quality value corresponding to cell handover, and the second value is less than the signal quality value corresponding to cell handover; then send the measurement report.

[0368] 4) Do not perform cell measurement, generate a measurement report, where the signal quality value of the measurement report is the second value, and the second value is less than the signal quality value corresponding to cell handover; then send the measurement report.

[0369] For method 3) and method 4), if the measurement report received by RAN1 indicates that the signal quality of the neighboring cell is poor, then RAN1 will not trigger cell handover.

[0370] S1210, the terminal establishes a connection with RAN2.

[0371] The terminal can determine to perform dual-connection handover according to the third information in S1208. The terminal can establish a connection with RAN2 based on certain criteria and initiate a registration process (similar to S1101 - S1110). After establishing a connection with RAN2, the terminal can switch from the first path (including the path of RAN1) to the second path (including the path of RAN2). For example, after the second path is established, if the signal quality of the first path deteriorates (e.g., is lower than the signal quality threshold), then the terminal can switch from the first path to the second path.

[0372] The method examples provided in the embodiments of the present application are introduced in detail above. It can be understood that for the corresponding device to implement the above functions, it includes the corresponding hardware structure and / or software module for executing each function. Those skilled in the art should easily realize that, combining the units and algorithm steps of each example described in the embodiments disclosed in this article, the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a certain function is executed in the way of hardware or computer software driving hardware depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but this implementation should not be considered to exceed the scope of the present application.

[0373] Figure 13 and Figure 14 are schematic structural diagrams of two possible communication devices provided by the embodiments of the present application. These communication devices can be used to implement the functions of the terminal, access network device, or core network device in the above method embodiments, and thus also have the beneficial effects possessed by the above method embodiments. In the embodiments of the present application, these communication devices can be Figure 1The terminal, RAN node, or core network device shown may also be a module (e.g., a chip) applied to the terminal, RAN node, or core network device.

[0374] As Figure 13 shown, the communication device 1300 includes a processing unit 1310 and a transceiver unit 1320. The transceiver unit 1320 performs a receiving step and / or a sending step under the control of the processing unit 1310. Among them, when the transceiver unit 1320 performs the sending step, it is a sending unit, and when the transceiver unit 1320 performs the receiving step, it is a receiving unit. The communication device 1300 is used to implement the functions of the terminal, access network device, or core network device in the method embodiments described above. Figures 9 - 12 the functions of the terminal, access network device, or core network device in the method embodiments described above.

[0375] When the communication device 1300 is used to implement Figures 9 - 12 the functions of the terminal in the method embodiments described above, the transceiver unit 1320 is used to: receive second information through a first path, where the second information includes a first set and / or a second set, the first set indicates cells supporting a first handover method, and the second set indicates cells supporting a second handover method; the processing unit 1310 is used to: determine to switch the first path to a second path through the first handover method or the second handover method, where the second path includes a connection between the terminal and a second cell. Among them, when switching the first path to the second path through the first handover method, the second cell belongs to the cells indicated by the first set, or the second cell does not belong to the cells indicated by the second set; or, when switching the first path to the second path through the second handover method, the second cell belongs to the cells indicated by the second set, or the second cell does not belong to the cells indicated by the first set.

[0376] Optionally, before receiving the second information through the first path, the transceiver unit 1320 is further used to: send first information through the first path, where the first information indicates that the terminal supports multiple handover methods, and the multiple handover methods include a first handover method and a second handover method.

[0377] Optionally, before determining to switch the first path to the second path through the first handover method or the second handover method, the transceiver unit 1320 is further used to: receive third information through the first path, where the third information indicates that the terminal is allowed to perform multiple handover methods, and the multiple handover methods include a first handover method and a second handover method.

[0378] Optionally, before receiving the second information through the first path, the transceiver unit 1320 is further used to: send fourth information through the first path, where the fourth information indicates that the terminal enables the mode of performing the second handover method.

[0379] Optionally, the processing unit 1310 is further configured to: if it is determined to switch the first path to the second path by the second switching method, adjust the signal quality value of the second cell from the first value to the second value, where the first value is greater than or equal to the signal quality value corresponding to the first switching method, and the second value is less than the signal quality value corresponding to the first switching method; the transceiver unit 1320 is further configured to: send the second value through the first path.

[0380] Optionally, the transceiver unit 1320 is further configured to: if it is determined to switch the first path to the second path by the second switching method, send the signal quality value of the second cell through the first path, where the signal quality value of the second cell is lower than the signal quality value corresponding to the trigger for executing the first switching method.

[0381] Optionally, the first switching method is a cell-based handover method, the second switching method is a dual-connection-based handover method, the first set is the first cell set, the second set is the second cell set, the PLMN corresponding to the cells in the first cell set is equivalent to the PLMN of the first cell, the PLMN corresponding to the cells in the second cell set is not equivalent to the PLMN of the first cell, and the first cell is the cell on the first path.

[0382] Optionally, the first switching method is a cell-based handover method, the second switching method is a dual-connection-based handover method, the first set is the first PLMN set, the second set is the second PLMN set, the PLMN in the first PLMN set is equivalent to the PLMN of the first cell, the PLMN in the second PLMN set is not equivalent to the PLMN of the first cell, and the first cell is the cell on the first path.

[0383] Optionally, the first switching method is a cell-based handover method, the second switching method is a dual-connection-based handover method, the first set is the first cell set, the second set is the second cell set, the PLMN corresponding to the cells in the first cell set is the same as the PLMN of the first cell, the PLMN corresponding to the cells in the second cell set is different from the PLMN of the first cell, and the first cell is the cell on the first path.

[0384] Optionally, the first switching method is a cell-based handover method, the second switching method is a dual-connection-based handover method, the first set is the first PLMN set, the second set is the second PLMN set, the PLMN in the first PLMN set includes the PLMN of the first cell, the PLMN in the second PLMN set does not include the PLMN of the first cell, and the first cell is the cell on the first path.

[0385] When the communication device 1300 is used to implement Figures 9 - 12When implementing the functions of the access network device in the method embodiments described above, the transceiver unit 1320 is configured to: receive permission information from the core network device, where the permission information indicates that the terminal is allowed to perform multiple handover methods, and the multiple handover methods include a first handover method and a second handover method; or, the permission information indicates that the terminal is allowed to perform the second handover method; according to the permission information, send second information to the terminal, where the second information includes a first set and / or a second set, the first set indicates the cells that support the first handover method, and the second set indicates the cells that support the second handover method.

[0386] Optionally, before receiving the permission information from the core network device, the transceiver unit 1320 is further configured to: receive first information from the terminal through a first path, where the first information indicates that the terminal supports multiple handover methods, and the multiple handover methods include a first handover method and a second handover method; send the first information to the core network device.

[0387] Optionally, the transceiver unit 1320 is further configured to: send third information to the terminal, where the third information indicates that the terminal is allowed to perform multiple handover methods, and the multiple handover methods include a first handover method and a second handover method.

[0388] Optionally, before sending the second information to the terminal, the transceiver unit 1320 is further configured to: receive fourth information from the terminal, where the fourth information indicates that the terminal enables the mode of performing the second handover method; specifically, the transceiver unit 1320 is further configured to: according to the fourth information, send the second information to the terminal.

[0389] Optionally, the transceiver unit 1320 is specifically configured to: send the second information to the terminal through a first path, where the cell corresponding to the first path is a first cell; the permission information includes at least one of the following information: fifth information, indicating that the access network device does not perform the first handover method; sixth information, indicating that the access network device performs the second handover method; a first PLMN set, where the PLMNs in the first PLMN set are not equivalent to the PLMN of the first cell, and the first cell is the cell on the first path; seventh information, indicating that the priority of the first handover method is lower than the priority of the second handover method.

[0390] Optionally, the transceiver unit 1320 is further configured to: send eighth information to the core network device, where the eighth information indicates that the handover method configuration of the terminal has been updated.

[0391] Optionally, the transceiver unit 1320 is specifically configured to: send a second piece of information to the terminal through a first path, where the cell corresponding to the first path is a first cell; the first handover mode is a handover mode based on cell handover, the second handover mode is a handover mode based on dual connectivity, the first set is a first cell set, the second set is a second cell set, the PLMNs corresponding to the cells in the first cell set are equivalent to the PLMN of the first cell, and the PLMNs corresponding to the cells in the second cell set are not equivalent to the PLMN of the first cell.

[0392] Optionally, the transceiver unit 1320 is specifically configured to: send a second piece of information to the terminal through a first path, where the cell corresponding to the first path is a first cell; the first handover mode is a handover mode based on cell handover, the second handover mode is a handover mode based on dual connectivity, the first set is a first PLMN set, the second set is a second PLMN set, the PLMNs in the first PLMN set are equivalent to the PLMN of the first cell, and the PLMNs in the second PLMN set are not equivalent to the PLMN of the first cell.

[0393] Optionally, the transceiver unit 1320 is specifically configured to: send a second piece of information to the terminal through a first path, where the cell corresponding to the first path is a first cell; the first handover mode is a handover mode based on cell handover, the second handover mode is a handover mode based on dual connectivity, the first set is a first cell set, the second set is a second cell set, the PLMNs corresponding to the cells in the first cell set are the same as the PLMN of the first cell, and the PLMNs corresponding to the cells in the second cell set are different from the PLMN of the first cell.

[0394] Optionally, the transceiver unit 1320 is specifically configured to: send a second piece of information to the terminal through a first path, where the cell corresponding to the first path is a first cell; the first handover mode is a handover mode based on cell handover, the second handover mode is a handover mode based on dual connectivity, the first set is a first PLMN set, the second set is a second PLMN set, the PLMNs in the first PLMN set include the PLMN of the first cell, and the PLMNs in the second PLMN set do not include the PLMN of the first cell.

[0395] When the communication device 1300 is used to implement Figures 9 - 12When implementing the functions of the access network device in the method embodiments described above, the transceiver unit 1320 is configured to: receive permission information from the core network device, where the permission information indicates that the terminal is allowed to perform multiple handover methods, and the multiple handover methods include a first handover method and a second handover method; or, the permission information indicates that the terminal is allowed to perform the second handover method; receive fourth information from the terminal through a first path, where the fourth information indicates that the terminal enables the mode of performing the second handover method; determine not to enable the mode of performing the first handover method according to the permission information and the fourth information; or, send second information to the terminal through the first path; or, send updated information of the second information to the terminal through the first path; where the second information includes a first set and / or a second set, the first set indicates the cells that support the first handover method, and the second set indicates the cells that support the second handover method.

[0396] Optionally, before receiving the permission information from the core network device, the transceiver unit 1320 is further configured to: receive first information from the terminal through the first path, where the first information indicates that the terminal supports multiple handover methods, and the multiple handover methods include a first handover method and a second handover method; send the first information to the core network device.

[0397] Optionally, the transceiver unit 1320 is further configured to: send third information to the terminal through the first path, where the third information indicates that the terminal is allowed to perform multiple handover methods.

[0398] Optionally, the permission information includes at least one of the following information: fifth information, indicating that the access network device does not perform the first handover method; sixth information, indicating that the access network device performs the second handover method; a first PLMN set, where the PLMNs in the first PLMN set are not equivalent to the PLMN of the first cell, and the first cell is the cell on the first path; seventh information, indicating that the priority of the first handover method is lower than the priority of the second handover method.

[0399] Optionally, the transceiver unit 1320 is further configured to: send eighth information to the core network device, where the eighth information indicates that the handover method configuration of the terminal has been updated.

[0400] Optionally, the first handover method is a handover method based on cell handover, the second handover method is a handover method based on dual connectivity, the first set is a first cell set, the second set is a second cell set, the PLMNs corresponding to the cells in the first cell set are equivalent to the PLMN of the first cell, the PLMNs corresponding to the cells in the second cell set are not equivalent to the PLMN of the first cell, and the first cell is the cell on the first path.

[0401] Optionally, the first handover method is a cell-based handover method, the second handover method is a dual-connection-based handover method, the first set is a first PLMN set, the second set is a second PLMN set, the PLMNs in the first PLMN set are equivalent to the PLMN of the first cell, the PLMNs in the second PLMN set are not equivalent to the PLMN of the first cell, and the first cell is a cell on the first path.

[0402] Optionally, the first handover method is a cell-based handover method, the second handover method is a dual-connection-based handover method, the first set is a first cell set, the second set is a second cell set, the PLMNs corresponding to the cells in the first cell set are the same as the PLMN of the first cell, the PLMNs corresponding to the cells in the second cell set are different from the PLMN of the first cell, and the first cell is a cell on the first path.

[0403] Optionally, the first handover method is a cell-based handover method, the second handover method is a dual-connection-based handover method, the first set is a first PLMN set, the second set is a second PLMN set, the PLMNs in the first PLMN set include the PLMN of the first cell, the PLMNs in the second PLMN set do not include the PLMN of the first cell, and the first cell is a cell on the first path.

[0404] When the communication device 1300 is used to implement Figures 9 - 12 the functions of the core network device in the method embodiments described above, the processing unit 1310 is configured to: determine permission information, where the permission information indicates that the terminal is allowed to perform multiple handover methods, and the multiple handover methods include the first handover method and the second handover method; or, the permission information indicates that the terminal is allowed to perform the second handover method; the transceiver unit 1320 is configured to: send the permission information.

[0405] Optionally, before determining the permission information, the transceiver unit 1320 is further configured to: receive first information, where the first information indicates that the terminal supports multiple handover methods, and the multiple handover methods include the first handover method and the second handover method.

[0406] Optionally, the permission information includes at least one of the following information: fifth information, indicating that the access network device does not perform the first handover method; sixth information, indicating that the access network device performs the second handover method; a first PLMN set, where the PLMNs in the first PLMN set are not equivalent to the PLMN of the first cell, the first cell is a cell on the first path, and the first path includes the connection between the terminal and the access network device; seventh information, indicating that the priority of the first handover method is lower than the priority of the second handover method.

[0407] Optionally, the permission information includes a first set and / or a second set. The first set indicates the PLMNs that support the first handover method, and the second set indicates the PLMNs that support the second handover method.

[0408] Optionally, the first handover method is a cell-based handover method, and the second handover method is a dual-connection-based handover method. The first set is a first PLMN set, and the second set is a second PLMN set. The PLMNs in the first PLMN set are equivalent to the PLMN of the first cell, and the PLMNs in the second PLMN set are not equivalent to the PLMN of the first cell. The first cell is a cell on the first path, and the first path includes the connection between the terminal and the access network device.

[0409] Optionally, the first handover method is a cell-based handover method, and the second handover method is a dual-connection-based handover method. The first set is a first PLMN set, and the second set is a second PLMN set. The PLMNs in the first PLMN set include the PLMN of the first cell, and the PLMNs in the second PLMN set do not include the PLMN of the first cell. The first cell is a cell on the first path, and the first cell is a cell on the first path. The first path includes the connection between the terminal and the access network device.

[0410] Optionally, the transceiver unit 1320 is further configured to: receive an eighth piece of information, where the eighth piece of information indicates that the handover method configuration of the terminal has been updated.

[0411] Those skilled in the art can clearly understand that when the communication device 1300 is used to implement the functions of a terminal, an access network device, or a core network device, the specific working process of the communication device 1300 and the technical effects generated by the execution steps can refer to the descriptions in the corresponding method embodiments described above. For the sake of brevity, they will not be elaborated here.

[0412] In the communication device 1300, the processing unit 1310 can be implemented by hardware or by software. When implemented by hardware, the processing unit 1310 can be a logic circuit, an integrated circuit, etc.; when the processing unit 1310 is implemented by software, the processing unit 1310 can be a general-purpose processor, which is implemented by reading the software code stored in the storage unit. The storage unit can be integrated in the processing unit 1310 or can exist independently outside the processing unit 1310.

[0413] Such as Figure 14As shown, the communication device 1400 includes a processor 1410 and an interface circuit 1420. The processor 1410 and the interface circuit 1420 are coupled to each other. It can be understood that the interface circuit 1420 can be a transceiver or an input / output interface. Optionally, the communication device 1400 may further include a memory 1430 for storing instructions executed by the processor 1410 or input data required for the processor 1410 to run the instructions or data generated after the processor 1410 runs the instructions.

[0414] When the communication device 1400 is used to implement Figures 9 - 12 the method shown, the processor 1410 is used to implement the functions of the above-mentioned processing unit 1410, and the interface circuit 1420 is used to implement the functions of the above-mentioned transceiver unit 1420.

[0415] When the communication device 1400 is a terminal chip (i.e., a chip applied to a terminal), the terminal chip implements the functions of the terminal in the above method embodiment. The terminal chip receives information from an access network device. It can be understood that this information is first received by other modules (such as a radio frequency module or an antenna) in the terminal and then sent by these modules to the terminal chip. The terminal chip sends information to the access network device. It can be understood that this information is first sent to other modules (such as a radio frequency module or an antenna) in the terminal and then sent by these modules to the access network device.

[0416] When the communication device 1600 is an access network device chip (i.e., a chip applied to an access network device), the access network device chip implements the functions of the access network device in the above method embodiment. The access network device chip receives information from a terminal. It can be understood that this information is first received by other modules (such as a radio frequency module or an antenna) in the access network device and then sent by these modules to the access network device chip. The access network device chip sends information to the terminal. It can be understood that this information is sent to other modules (such as a radio frequency module or an antenna) in the access network device and then sent by these modules to the terminal.

[0417] When the communication device 1600 is a core network device chip (i.e., a chip applied to an access network device), the core network device chip implements the functions of the core network device in the above method embodiment. The core network device chip receives information from an access network device. It can be understood that this information is first received by other modules (such as a communication interface module) in the access network device and then sent by these modules to the core network device chip. The core network device chip sends information to the access network device. It can be understood that this information is sent to other modules (such as a communication interface module) in the core network device and then sent by these modules to the access network device.

[0418] In this application, when entity A sends information to entity B, it can be directly sent from A to B, or A can indirectly send it to B through other entities. Similarly, when entity B receives information from entity A, entity B can directly receive the information sent by entity A, or entity B can indirectly receive the information sent by entity A through other entities. Here, entity A and B can be RAN nodes or terminals, or modules inside RAN nodes or terminals. The sending and receiving of information can be information interaction between a RAN node and a terminal, for example, information interaction between a base station and a terminal; the sending and receiving of information can also be information interaction between two RAN nodes, for example, information interaction between a CU and a DU; the sending and receiving of information can also be information interaction between different modules within a device, for example, information interaction between a terminal chip and other modules of the terminal, or information interaction between a base station chip and other modules in the base station.

[0419] It can be understood that the processor in the embodiments of this application can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. The general-purpose processor can be a microprocessor or any conventional processor.

[0420] The method steps in the embodiments of this application can be implemented in hardware or in software instructions executable by a processor. The software instructions can be composed of corresponding software modules, and the software modules can be stored in a random access memory, flash memory, read-only memory, programmable read-only memory, erasable programmable read-only memory, electrically erasable programmable read-only memory, registers, hard disks, removable hard disks, compact disc read-only memories (CD-ROMs), or any other form of storage medium well known in the art. An exemplary storage medium is coupled to the processor so that the processor can read information from the storage medium and write information to the storage medium. The storage medium can also be a component of the processor. The processor and the storage medium can be located in an ASIC. Additionally, the ASIC can be located in a base station or a terminal. The processor and the storage medium can also exist as discrete components in a base station or a terminal.

[0421] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer programs or instructions. When the computer program or instructions are loaded and executed on a computer, the processes or functions described in the embodiments of the present application are executed in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, a network device, a user device, or other programmable devices. The computer program or instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer program or instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center in a wired or wireless manner. The computer-readable storage medium can be any available medium that can be accessed by a computer, or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium, such as a floppy disk, a hard disk, or a magnetic tape; it can also be an optical medium, such as a digital video disc; or it can be a semiconductor medium, such as a solid-state drive. The computer-readable storage medium can be a volatile or non-volatile storage medium, or can include both volatile and non-volatile types of storage media.

[0422] Finally, the following points regarding the embodiments of the present application are noted:

[0423] First, in the embodiments of the present application, the first, second, and various numerical numbers are only for the convenience of description and are not used to limit the scope of the embodiments of the present application. For example, the first primary cell and the second primary cell represent two primary cells, and these two primary cells may be two different cells or the same cell.

[0424] Second, in the embodiments of the present application, "indication" can include direct indication and indirect indication, and can also include explicit indication and implicit indication. The information indicated by a certain piece of information is called the information to be indicated. In the specific implementation process, there are many ways to indicate the information to be indicated. For example, the information to be indicated can be directly indicated, such as the information to be indicated itself or the index of the information to be indicated. It is also possible to indirectly indicate the information to be indicated by indicating other information, where there is an association relationship between the other information and the information to be indicated. It is also possible to only indicate a part of the information to be indicated, while the other parts of the information to be indicated are known or pre-agreed. For example, it is possible to implement the indication of the information to be indicated by relying on a pre-agreement (such as protocol regulations) on the existence of a certain cell, thereby reducing the indication overhead to a certain extent.

[0425] Third, the "protocol" involved in the embodiments of the present application may refer to the standard protocols in the communication field. For example, it may include LTE protocol, NR protocol, and related protocols in future communication systems. The present application does not limit this.

[0426] Fourth, "predefined" or "preconfigured" can be implemented by pre-saving corresponding codes, tables, or other means that can indicate relevant information in a device (such as a terminal or a base station). The present application does not limit the specific implementation method. Herein, "saving" may mean saving in one or more memories. The one or more memories may be separately provided, or integrated in a processor or a communication device; the one or more memories may also be partially separately provided and partially integrated in a processor or a communication device. The type of the memory may be any form of storage medium, and the present application does not limit this.

[0427] Fifth, "at least one" means one or more, and "a plurality" means two or more. "And / or" describes the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, B exists alone, or both A and B exist simultaneously. Herein, A and B can be single objects or multiple objects. The character " / " generally represents an "or" relationship between the associated objects before and after. "At least one (item)" or its similar expression refers to any combination of these items, including any combination of single item (item) or plural items (items). For example, at least one (item) of a, b, and c can represent: a, or, b, or, c, or, a and b, or, a and c, or, b and c, or, a, b, and c. Herein, a, b, and c can be single objects or multiple objects respectively.

[0428] Sixth, in the embodiments of the present application, descriptions such as "when...", "in the case of...", "if", and "when" all refer to that in a certain objective situation, a device (such as a terminal or a base station) will perform corresponding processing. It does not limit the time, nor does it require the device to have a judgment action during implementation, nor does it mean there are other limitations.

[0429] Seventh, in each embodiment of the present application, if there is no special explanation and logical conflict, the terms and / or descriptions between different embodiments are consistent and can be referenced to each other. The technical features in different embodiments can be combined to form new embodiments according to their inherent logical relationships.

Claims

1. A communication method, characterized in that, The method includes: Receiving second information through a first path, the second information including a first set and / or a second set, the first set indicating cells supporting a first handover mode, and the second set indicating cells supporting a second handover mode; Determining to switch the first path to a second path through the first handover mode or the second handover mode, the second path including a connection between the terminal and a second cell, wherein, When switching the first path to the second path through the first handover mode, the second cell belongs to the cells indicated by the first set, or the second cell does not belong to the cells indicated by the second set; or, When switching the first path to the second path through the second handover mode, the second cell belongs to the cells indicated by the second set, or the second cell does not belong to the cells indicated by the first set.

2. The method according to claim 1, characterized in that, Before determining to switch the first path to the second path through the first handover mode or the second handover mode, the method further includes: Receiving third information through the first path, the third information indicating that the terminal is allowed to perform multiple handover modes, the multiple handover modes including the first handover mode and the second handover mode.

3. The method according to claim 1 or 2, characterized in that, Before receiving the second information through the first path, the method further includes: Sending fourth information through the first path, the fourth information indicating that the terminal enables a mode for performing the second handover mode.

4. The method according to any one of claims 1 to 3, characterized in that, The method further includes: If it is determined to switch the first path to the second path through the second handover mode, adjusting a signal quality value of the second cell from a first value to a second value, the first value being greater than or equal to a signal quality value corresponding to the first handover mode, and the second value being less than the signal quality value corresponding to the first handover mode; Sending the second value through the first path.

5. The method according to any one of claims 1 to 4, characterized in that, Before receiving the second information through the first path, the method further includes: Sending first information through the first path, the first information indicating that the terminal supports multiple handover modes, the multiple handover modes including the first handover mode and the second handover mode.

6. The method according to any one of claims 1 to 5, characterized in that, The first handover mode is a handover mode based on cell handover, the second handover mode is a handover mode based on dual connectivity, the first set is a first cell set, the second set is a second cell set, the public land mobile network (PLMN) corresponding to the cells in the first cell set is equivalent to the PLMN of the first cell, the PLMN corresponding to the cells in the second cell set is not equivalent to the PLMN of the first cell, and the first cell is the cell corresponding to the first path.

7. The method according to any one of claims 1 to 5, characterized in that, The first handover mode is a handover mode based on cell handover, the second handover mode is a handover mode based on dual connectivity, the first set is a first PLMN set, the second set is a second PLMN set, the PLMN in the first PLMN set is equivalent to the PLMN of the first cell, the PLMN in the second PLMN set is not equivalent to the PLMN of the first cell, and the first cell is the cell corresponding to the first path.

8. The method according to any one of claims 1 to 5, characterized in that, The first handover method is a handover method based on cell handover, the second handover method is a handover method based on dual connectivity, the first set is the first cell set, the second set is the second cell set, the PLMN corresponding to the cells in the first cell set is the same as the PLMN of the first cell, the PLMN corresponding to the cells in the second cell set is different from the PLMN of the first cell, and the first cell is the cell corresponding to the first path.

9. The method according to any one of claims 1 to 5, characterized in that The first handover method is a handover method based on cell handover, the second handover method is a handover method based on dual connectivity, the first set is the first PLMN set, the second set is the second PLMN set, the PLMNs in the first PLMN set include the PLMN of the first cell, the PLMNs in the second PLMN set do not include the PLMN of the first cell, and the first cell is the cell corresponding to the first path.

10. A communication method, characterized in that, The method includes: Receiving permission information from a core network device, the permission information indicating that the terminal is allowed to perform multiple handover methods, the multiple handover methods including the first handover method and the second handover method; or, the permission information indicating that the terminal is allowed to perform the second handover method; According to the permission information, sending second information to the terminal, the second information including the first set and / or the second set, the first set indicating the cells that support the first handover method, and the second set indicating the cells that support the second handover method.

11. The method according to claim 10, wherein Before receiving the permission information from the core network device, the method further includes: Receiving first information from the terminal, the first information indicating that the terminal supports multiple handover methods, the multiple handover methods including the first handover method and the second handover method; Sending the first information to the core network device.

12. The method according to claim 10 or 11, characterized in that, The method further includes: Sending third information to the terminal, the third information indicating that the terminal is allowed to perform multiple handover methods, the multiple handover methods including the first handover method and the second handover method.

13. The method according to claim 12, wherein Before sending the second information to the terminal, the method further includes: Receiving fourth information from the terminal, the fourth information indicating that the terminal enables the mode of performing the second handover method; Sending the second information to the terminal includes: According to the fourth information, sending the second information to the terminal.

14. The method according to any one of claims 10 to 13, characterized in that, Sending the second information to the terminal includes: sending the second information to the terminal through a first path, where the cell corresponding to the first path is the first cell; The permission information includes at least one of the following information: Fifth information, indicating that the access network device does not perform the first handover method; Sixth information, indicating that the access network device performs the second handover method; The first public land mobile network (PLMN) set, where the PLMNs in the first PLMN set are not equivalent to the PLMN of the first cell; Seventh information, indicating that the priority of the first handover method is lower than the priority of the second handover method.

15. The method according to any one of claims 10 to 14, characterized in that The method further includes: Sending eighth information to the core network device, the eighth information indicating that the handover method configuration of the terminal has been updated.

16. The method according to any one of claims 10 to 15, characterized in that Sending the second information to the terminal includes: sending the second information to the terminal through a first path, where the cell corresponding to the first path is a first cell; the first handover method is a handover method based on cell handover, the second handover method is a handover method based on dual connectivity, the first set is a first cell set, the second set is a second cell set, the PLMN corresponding to the cells in the first cell set is equivalent to the PLMN of the first cell, and the PLMN corresponding to the cells in the second cell set is not equivalent to the PLMN of the first cell.

17. The method according to any one of claims 10 to 15, characterized in that, Sending the second information to the terminal includes: sending the second information to the terminal through a first path, where the cell corresponding to the first path is a first cell; the first handover method is a handover method based on cell handover, the second handover method is a handover method based on dual connectivity, the first set is a first PLMN set, the second set is a second PLMN set, the PLMN in the first PLMN set is equivalent to the PLMN of the first cell, and the PLMN in the second PLMN set is not equivalent to the PLMN of the first cell.

18. The method according to any one of claims 10 to 15, characterized in that Sending the second information to the terminal includes: sending the second information to the terminal through a first path, where the cell corresponding to the first path is a first cell; the first handover method is a handover method based on cell handover, the second handover method is a handover method based on dual connectivity, the first set is a first cell set, the second set is a second cell set, the PLMN corresponding to the cells in the first cell set is the same as the PLMN of the first cell, and the PLMN corresponding to the cells in the second cell set is different from the PLMN of the first cell.

19. The method according to any one of claims 10 to 15, characterized in that Sending the second information to the terminal includes: sending the second information to the terminal through a first path, where the cell corresponding to the first path is a first cell; the first handover method is a handover method based on cell handover, the second handover method is a handover method based on dual connectivity, the first set is a first PLMN set, the second set is a second PLMN set, the PLMN in the first PLMN set includes the PLMN of the first cell, and the PLMN in the second PLMN set does not include the PLMN of the first cell.

20. A communication method, characterized in that, The method includes: Determining permission information, where the permission information indicates that the terminal is allowed to perform multiple handover methods, and the multiple handover methods include a first handover method and a second handover method; or, the permission information indicates that the terminal is allowed to perform the second handover method; Sending the permission information.

21. The method according to claim 20, wherein Before determining the permission information, the method further includes: Receiving first information, where the first information indicates that the terminal supports multiple handover methods, and the multiple handover methods include the first handover method and the second handover method.

22. The method according to claim 20 or 21, characterized in that, The permission information includes at least one of the following information: Fifth information, indicating that the access network device does not perform the first handover method; Sixth information, indicating that the access network device performs the second handover method; A first set of public land mobile networks (PLMNs), where the PLMNs in the first PLMN set are not equivalent to the PLMN of the first cell, the first cell being the cell corresponding to the first path, and the first path including the connection between the terminal and the access network device; Seventh information indicating that the priority of the first handover method is lower than the priority of the second handover method.

23. The method according to any one of claims 20 to 22, characterized in that, The permission information includes a first set and / or a second set. The first set indicates the PLMNs that support the first handover method, and the second set indicates the PLMNs that support the second handover method.

24. The method according to claim 23, wherein The first handover method is a cell-based handover method, and the second handover method is a dual-connection-based handover method. The first set is the first PLMN set, and the second set is the second PLMN set. The PLMNs in the first PLMN set are equivalent to the PLMN of the first cell, and the PLMNs in the second PLMN set are not equivalent to the PLMN of the first cell. The first cell is the cell corresponding to the first path, and the first path includes the connection between the terminal and the access network device.

25. The method according to claim 23, characterized in that, The first handover method is a cell-based handover method, and the second handover method is a dual-connection-based handover method. The first set is the first PLMN set, and the second set is the second PLMN set. The PLMNs in the first PLMN set include the PLMN of the first cell, and the PLMNs in the second PLMN set do not include the PLMN of the first cell. The first cell is the cell corresponding to the first path, and the first path includes the connection between the terminal and the access network device.

26. The method according to any one of claims 20 to 25, characterized in that, The method further includes: Receiving eighth information indicating that the handover method configuration of the terminal has been updated.

27. A communication device, characterized in that, Including: A module for executing the method according to any one of claims 1 to 9, or a module for executing the method according to any one of claims 10 to 19, or a module for executing the method according to any one of claims 20 to 26.

28. A communication device, characterized in that, Including: A processor and an interface circuit. The interface circuit is used to receive signals from other communication devices and transmit them to the processor or send signals from the processor to other communication devices. The processor implements, through logic circuits or by executing code instructions: the method according to any one of claims 1 to 9, or the method according to any one of claims 10 to 19, or the method according to any one of claims 20 to 26.

29. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program or instructions. When the computer program or instructions are executed by a communication device, they implement the method according to any one of claims 1 to 9, or implement the method according to any one of claims 10 to 19, or implement the method according to any one of claims 20 to 26.

Images