A communication method and apparatus

Abstract

A communication method and apparatus are disclosed. The method includes: a session management network element receiving first information from a user equipment (UE), the first information indicating that the UE requests a connection to a target IMS network, the target IMS network being one of multiple IMS networks provided by a target service provider; the session management network element determining first call information based on the first information, the first call information instructing a target proxy call network element to establish a connection between the UE and the target IMS network; and the session management network element sending the first call information to the UE. This technical solution enables a single non-public network to connect to multiple IMS networks, providing UEs with their respective IMS network services to UEs of different service providers, without requiring additional local user servers in the non-public network, thus reducing deployment costs.

Description

[0001] This application claims priority to Chinese Patent Application No. PCT / CN2020 / 125916, filed on November 2, 2020, entitled “A Communication Method and Apparatus”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of wireless communication technology, and in particular to a communication method and apparatus. Background Technology

[0003] The IP multimedia subsystem (IMS) network is a type of data network (DN). The IMS network connects to a standalone non-public network (SNPN) and provides IMS services to user equipment (UE) in the SNPN.

[0004] IMS networks have service provider attributes. For example, an IMS network provided by service provider A can only provide services to user equipment of service provider A (i.e., user equipment with subscription data from service provider A), and cannot provide services to user equipment of other IMS network service providers. When a non-public network connects to an IMS network, for example, if the IMS network is IMS network A and its service provider is service provider A, the non-public network can provide the address information of the proxy call element of IMS network A to the user equipment with subscription data from service provider A. Thus, the user equipment can establish a connection with IMS network A through the address information of the proxy call element. However, for other user equipment, for example, if the subscription data of another user equipment belongs to service provider B, and the IMS network provided by service provider B does not include IMS network A, even if the other user equipment obtains the address information of the proxy call element of IMS network A, it cannot establish a connection with IMS network A.

[0005] There is an urgent need for a method to enable user equipment to connect to the IMS network corresponding to the user equipment through a non-public network. Summary of the Invention

[0006] The purpose of this application is to provide a communication method and apparatus for enabling user equipment to connect to the service provider's IMS network via a non-public network.

[0007] In a first aspect, this application provides a communication method that can be executed by a session management network element or by a component (such as a chip or circuit) within the session management network element.

[0008] In one possible implementation, the method is executed by a session management network element, and includes: the session management network element receiving first information from a user equipment, the session management network element and the user equipment being located in a non-public network connected to multiple IMS networks, the first information being used to instruct the user equipment to request a connection to a target IMS network, the target IMS network being one of multiple IMS networks provided by a target service provider; the session management network element determining first call information based on the first information, the first call information instructing a target proxy call network element, the first call information being used to establish a connection between the user equipment and the target IMS network; and the session management network element sending the first call information to the user equipment.

[0009] The above technical solution enables a single non-public network to connect to multiple IMS networks, providing IMS network services to user equipment from different service providers. Furthermore, the user equipment sends first information to the session management network element, which can then determine the target IMS network from which the user equipment requests a connection, thereby establishing a session connection between the user equipment and the target IMS network. This eliminates the need for a new local user server in the non-public network, helping to reduce deployment costs.

[0010] In one possible implementation, the first information includes the identification information of the target service provider and / or, the first call information.

[0011] In the above technical solution, the session management network element can determine the target IMS network provided by the target service provider based on the identification information of the target service provider in the first information, and establish a session connection between the user equipment and the target IMS network. Alternatively, the session management network element can determine the target proxy call network element indicated by the first call information and the target IMS network where the target proxy call network element is located based on the first call information in the first information, and establish a session connection between the user equipment and the target IMS network.

[0012] In one possible implementation, the first information is data network name information, which includes the identification information of the target service provider.

[0013] In the above technical solution, the user equipment can send enhanced data network name information to the session management network element. The enhanced data network name information includes the identification information of the target service provider. The session management network element can obtain the identification information of the target service provider from the data network name information and establish a session connection between the user equipment and the target IMS network based on the existing session establishment process.

[0014] In one possible implementation, the target proxy call network element is located in a non-public network, and the method further includes: a session management network element sending second information to the target proxy call network element or a policy control network element; wherein the second information includes the identification information of the user equipment and the identification information of the target service provider, and the second information is used to instruct the target proxy call network element to send the IMS message from the user equipment to the target query call network element of the target IMS network. In one possible implementation, the second information further includes second call information for instructing the target query call network element.

[0015] In the above technical solution, the session management network element sends the second information to the target proxy call network element, or the session management network element sends the second message to the target proxy call network element through the policy control network element. The target proxy call network element can determine the correspondence between the user equipment identification information and the target query call network element based on the second information, so that the target proxy call network element can send the IMS message from the user equipment to the corresponding target query call network element.

[0016] In one possible implementation, the target proxy call element is located in a non-public network, and the method further includes: the session management element determining the second call information corresponding to the target service provider based on the correspondence between the service provider and the query call information; the session management element determining the target association relationship, which includes the association relationship between the user equipment identification information and the second call information, or the target association relationship includes the association relationship between the user equipment identification information, the second call information and the identification information of the target service provider; and the session management element sending the target association relationship to the target proxy call element or the policy control element.

[0017] In the above technical solution, the session management network element can determine the target association relationship between the user equipment's identification information and the second call information based on the target service provider and its corresponding inquiry call information (i.e., the second call information), as well as the user equipment's identification information. The session management network element sends the target association relationship to the target proxy call network element, or the policy control network element sends the target association relationship to the target proxy call network element. The target proxy call network element can then send the IMS message from the user equipment to the corresponding target inquiry call network element based on the target association relationship.

[0018] Secondly, this application provides a communication method that can be executed by a user equipment or by a component (such as a chip or circuit) in the user equipment.

[0019] In one possible implementation, the method is performed by a user equipment (UE) and includes: the UE sending first information to a session management network element (SLE), wherein the UE and the SLE are located in a non-public network connected to multiple IMS networks; the first information instructs the UE to request a connection to a target IMS network, which is one of the multiple IMS networks provided by a target service provider; and the UE receiving first call information from the SLE, which instructs a target agent call network element to establish a connection between the UE and the target IMS network.

[0020] In one possible implementation, the first information includes the identification information of the target service provider and / or, the first call information.

[0021] In one possible implementation, the first information is data network name information, which includes the identification information of the target service provider.

[0022] In one possible implementation, the data network name information is obtained by the user equipment from the access and mobility management network element, the session management network element, or the access network device.

[0023] In one possible implementation, the first information includes first call information. Before the user equipment sends the first information to the session management network element, the method further includes: the user equipment receiving third information from the access network device. The third information includes a first service provider and the proxy call information corresponding to the first service provider. The proxy call information corresponding to the first service provider is the first call information.

[0024] In the above technical solution, the user equipment (UE) can determine, based on the acquired third information, whether a target IMS network providing services to the UE exists among multiple IMS networks connected to a non-public network. If the UE determines that the third information contains the identifier of the service provider to which the UE belongs, then the target IMS network exists among the multiple IMS networks, and the UE can establish a session connection through the non-public network to obtain the IMS services provided by the target IMS network. If the UE determines that the third information does not contain the identifier of the service provider to which the UE belongs, then the target IMS network does not exist among the multiple IMS networks, and the UE cannot establish a session connection through the non-public network to obtain the IMS services provided by the target IMS network.

[0025] In one possible implementation, the first information includes first call information. Before the user equipment sends the first information to the session management network element, the method further includes: the user equipment sending a query request to the domain name system server; the query request includes identification information of a non-public network; the user equipment receiving a query response from the domain name system server, the query response including the first call information, the target proxy call network element indicated by the first call information being located in the target IMS network and connected to a non-public network.

[0026] In the above technical solution, the user equipment can send a query request to the Domain Name System (DNS) server, which includes the identification information of a non-public network. If the DNS server determines that it has obtained proxy call information corresponding to the target IMS network domain name, it sends a query response to the user equipment, including the proxy call information (first call information) corresponding to the target IMS network domain name. The user equipment can then establish a session connection through the non-public network to obtain IMS services provided by the target IMS network. If the DNS server determines that it has not obtained proxy call information corresponding to the target IMS network domain name, it sends a query failure message to the user equipment, or indicates that no target IMS network is connected to the non-public network. Thus, the user equipment can determine that it cannot establish a session connection through the non-public network to obtain IMS services provided by the target IMS network.

[0027] Thirdly, this application provides a communication method that can be executed by a policy control network element or by a component (such as a chip or circuit) within the policy control network element.

[0028] In one possible implementation, the method is executed by a policy control network element, and includes: the policy control network element receiving second information from a session management network element, the second information including identification information of a user equipment and identification information of a target service provider; the policy control network element determining a target association relationship based on the correspondence between the service provider and the inquiry call information and the second information, the target association relationship including the association relationship between the user equipment identification information and the second call information, or the target association relationship including the association relationship between the user equipment identification information, the second call information and the identification information of the target service provider, the second call information indicating a target inquiry call network element, the target inquiry call network element being located in a target IMS network and connected to a target proxy call network element in a non-public network; and the policy control network element sending the target association relationship to the target proxy call network element.

[0029] In the above technical solution, the policy control network element can determine the target association relationship based on the correspondence between the service provider and the inquiry call information, and the second information, and send the target association relationship to the target proxy call network element. The target proxy call network element can then send the IMS message from the user equipment to the corresponding target inquiry call network element based on the target association relationship.

[0030] Fourthly, this application provides a communication method that can be executed by a target agent calling network element or by a component (such as a chip or circuit) in the target agent calling network element.

[0031] In one possible implementation, the method is executed by a target proxy calling network element, and includes: the target proxy calling network element receiving IMS information from a user equipment, the IMS information including the user equipment's identification information, the target proxy calling network element and the user equipment being located in a non-public network; the target proxy calling network element determining second calling information based on a target association relationship and the user equipment's identification information, the target association relationship including the association relationship between the user equipment's identification information and the second calling information; and the target proxy calling network element sending IMS information to a target query calling network element indicated by the second calling information, the target query calling network element being located in a target IMS network.

[0032] In one possible implementation, before the target agent calling network element receives IMS information from the user equipment, it also includes: the target agent calling network element receiving target association relationships from the policy control network element or the session management network element.

[0033] In one possible implementation, before the target agent call network element receives IMS information from the user equipment, it further includes: the target agent call network element receiving identification information of the user equipment and identification information of the target service provider from the policy control network element or session management network element; the target agent call network element determining the target association relationship based on the correspondence between the service provider and the query call information.

[0034] In one possible implementation, the target association also includes the identification information of the target service provider.

[0035] In the above technical solution, the target proxy call network element can receive target association relationships from the policy control network element or the session management network element, or receive the identification information of the user equipment and the identification information of the target service provider from the policy control network element or the session management network element, and determine the target association relationship. Based on this target association relationship, the target proxy call network element can send IMS messages from the user equipment to the corresponding target query call network element.

[0036] Fifthly, this application provides a communication method that can be executed by a user equipment or by a component (such as a chip or circuit) in the user equipment.

[0037] In one possible implementation, the method is performed by a user equipment (UE), and includes: the UE sending network information of a first IMS network supported by the UE to a core network device; the UE receiving fourth information from the core network device, the fourth information indicating whether establishing a connection between the UE and the first IMS network is supported. Since a non-public network can provide the UE with a connection to obtain IMS services, it can provide the connection between the UE and the IMS network. Therefore, it is understood that the fourth information indicates whether the non-public network supports establishing a connection between the UE and the first IMS network. This description applies to other aspects, which will not be elaborated further. Establishing a connection between the UE and the first IMS network can be understood as the UE establishing a session with the data network to which the first IMS network belongs, or as the UE establishing an Internet Protocol (IP) connection with a call agent network element of the first IMS network, or as the UE establishing an IP connection with the first IMS network.

[0038] In one possible implementation, the user equipment (UE) can send network information of the first IMS network to the core network equipment via other devices: If the core network equipment is an access and mobility management (AMI) element, the UE can send the network information of the first IMS network to the AMI element via the access network equipment. If the core network equipment is a session management (SRM) element, the UE can send the network information of the first IMS network to the SRM element sequentially via the access network equipment and the AMI element.

[0039] In the above technical solution, the user equipment (UE) sends the network information of the first IMS requested by the UE to the core network equipment. The core network equipment can determine, based on the network information of the first IMS, whether one or more IMS networks connected to the non-public network accessed by the UE include the first IMS network, and then sends fourth information to the UE so that the UE can determine and use the IMS service. That is, the core network equipment determines whether there is an IMS network that can provide IMS service to the UE among one or more IMS networks connected to the non-public network accessed by the UE, and then sends fourth information to the UE. Specifically, the fourth information can be used to indicate whether it supports establishing a connection between the UE and the first IMS network. The UE can determine whether to request IMS service based on the fourth information. In this method, if there is an IMS network that can provide IMS service to the UE among one or more IMS networks connected to the non-public network accessed by the UE (i.e., the fourth information indicates support for establishing a connection between the UE and the first IMS network), the UE will request IMS service. By using the above method, the user equipment only initiates a request to obtain IMS services after confirming the existence of an IMS network capable of providing IMS services to itself. This reduces the process of user equipment blindly initiating a request to obtain IMS services due to uncertainty about the existence of such an IMS network, and subsequently receiving a rejection message. Since both initiating a request to obtain IMS services and receiving a rejection message during this process incur signaling consumption and network resource occupation, this method can further reduce signaling consumption and network resource occupation.

[0040] In one possible implementation, the user equipment sends network information of the first IMS network to the core network device through a registration process. The fourth information indicates support for establishing a connection between the user equipment and the first IMS network. The method further includes: the user equipment sending session establishment request information to the core network device. The session establishment request message is used to establish a connection between the user equipment and the first IMS network.

[0041] In the above technical solution, the user equipment can send network information of the first IMS network to the core network equipment during the registration process. Correspondingly, the core network equipment can respond to the network information of the first IMS network during the registration process by sending fourth information to the user equipment. Thus, the user equipment can further determine whether to send session establishment request information to the core network equipment to establish a connection between the user equipment and the first IMS network through the registration process. This method can help reduce signaling overhead and network resource consumption.

[0042] In one possible implementation, the user equipment sends network information of the first IMS network to the core network device through a session establishment process. The fourth information indicates support for establishing a connection between the user equipment and the first IMS network. The method further includes: the user equipment obtaining the address information of the proxy call network element corresponding to the first IMS network; and the user equipment establishing a connection with the proxy call network element based on the address information.

[0043] In one possible implementation, the user equipment can obtain the address information of the proxy call network element corresponding to the first IMS network from a domain name server or a session management network element.

[0044] In one possible implementation, the fourth information may include the address information of the proxy calling network element corresponding to the first IMS network. This address information can be used to indicate support for establishing a connection between the user equipment and the first IMS network. It is understood that if the user equipment receives the address information of the proxy calling network element corresponding to the first IMS network during session establishment, it can establish a connection with the proxy calling network element based on this address information, thereby obtaining IMS services from the first IMS network.

[0045] In the above technical solution, the user equipment can send network information of the first IMS network to the core network device during the session establishment process. Correspondingly, the core network device can respond to the network information of the first IMS network and send fourth information to the user equipment during the session establishment process. Thus, the user equipment can determine whether to request to establish a connection to the first IMS network during the session establishment process. This method can help reduce signaling overhead and network resource consumption.

[0046] In one possible implementation, the user equipment sends network information of the first IMS network to the core network device through a session establishment process. The fourth information indicates that the establishment of a connection between the user equipment and the first IMS network is not supported. The fourth information includes session establishment rejection information.

[0047] In the above technical solution, the user equipment (UE) can send network information of the first IMS network to the core network device during the session establishment process. Correspondingly, the core network device can respond to the network information of the first IMS network during the session establishment process by sending fourth information to the UE. This fourth information may include session establishment rejection information. For example, this fourth information may be session establishment rejection information. Based on the session establishment rejection information, the UE can determine that it cannot obtain IMS services through a non-public network connection to the IMS network it can access. Therefore, the UE will no longer request IMS services from the core network device or will not establish a connection with the non-public network connection to the IMS network, which helps reduce signaling overhead and network resource consumption.

[0048] In one possible implementation, the network information includes one or more of the following: service provider identifier, network identifier, network domain name, data network name, and address information of the proxy calling network element. In another possible implementation, the user equipment can send one or more of the following to the core network equipment: service provider identifier, network identifier, network domain name, data network name, and address information of the proxy calling network element of the first IMS network supported by the user equipment. Thus, the core network equipment can send fourth information to the user equipment based on the information received from the user equipment.

[0049] In one possible implementation, the fourth information includes one or more of the following: session establishment acceptance information, session establishment rejection information, service provider identifier, network identifier, network domain name, address information of the proxy calling network element, and data network name information. In another possible implementation, the session establishment acceptance information may include message type information and / or parameter information of the session establishment acceptance message. The session establishment rejection information may include message type information and / or parameter information of the session establishment rejection message.

[0050] In one possible implementation, the fourth information may be network information of a second IMS network, wherein the second IMS network may be an IMS network selected by the core network device from one or more IMS networks connected to a non-public network accessed by the user equipment. In another possible implementation, the fourth information may include one or more of the following: the service provider identifier, network identifier, network domain name, address information of the proxy calling network element, and data network name of the second IMS network. The second IMS network may be the same as or different from the first IMS network. When the second IMS network is the same as the first IMS network, the network information of the second IMS network can be used to implicitly indicate support for establishing a connection between the user equipment and the first IMS network. When the second IMS network is different from the first IMS network, the network information of the second IMS network can be used to implicitly indicate that establishing a connection between the user equipment and the first IMS network is not supported.

[0051] In one possible implementation, the fourth information may be indication information, which may be used to indicate whether or not to support establishing a connection between the user equipment and the first IMS network.

[0052] For example, the indication information can be a single bit, multiple bits, or a string. When the indication information is a single bit, a value of 1 indicates support for establishing a connection between the user equipment and the first IMS network, and a value of 0 indicates that establishing a connection between the user equipment and the first IMS network is not supported. Alternatively, when the indication information is a single bit, a value of 0 indicates support for establishing a connection between the user equipment and the first IMS network, and a value of 1 indicates that establishing a connection between the user equipment and the first IMS network is not supported. When the indication information is multiple bits, one type of multiple bits can indicate support for establishing a connection between the user equipment and the first IMS network, and another type of multiple bits can indicate that establishing a connection between the user equipment and the first IMS network is not supported. When the indication information is a string, one type of string can indicate support for establishing a connection between the user equipment and the first IMS network, and another type of string can indicate that establishing a connection between the user equipment and the first IMS network is not supported.

[0053] When the fourth information indicates support for establishing a connection between the user equipment and the first IMS network, the user equipment can obtain the address information of the proxy call network element corresponding to the first IMS network from the domain name system server or from the session management network element, and then establish a connection with the proxy call network element based on the address information, thereby obtaining the IMS service of the first IMS network.

[0054] Sixthly, this application provides a communication method that can be executed by a core network device or by a component (such as a chip or circuit) in the core network device.

[0055] In one possible implementation, the method is executed by a core network device, and includes: the core network device acquiring network information of a first IMS network, which is an IMS network supported by the user equipment; the core network device sending fourth information to the user equipment, the fourth information indicating whether it supports establishing a connection between the user equipment and the first IMS network. Here, establishing a connection between the user equipment and the first IMS network can be understood as the user equipment establishing a session with the data network to which the first IMS network belongs, or it can be understood as the user equipment establishing an IP connection with a call agent network element of the first IMS network, or simply establishing an IP connection between the user equipment and the first IMS network.

[0056] In one possible implementation, the core network device obtains network information of the first IMS network, including: the core network device receiving the network information of the first IMS network from the user equipment through a registration process; the fourth information indicates support for establishing a connection between the user equipment and the first IMS network, and the method further includes: the core network device receiving a session establishment request message from the user equipment, the session establishment request message being used to establish a connection between the user equipment and the first IMS network.

[0057] In one possible implementation, the core network device obtains network information of the first IMS network, including: the core network device receiving the network information of the first IMS network from the user equipment through a session establishment process; the fourth information indicates support for establishing a connection between the user equipment and the first IMS network, the fourth information including session establishment acceptance information and / or address information of the proxy call network element corresponding to the first IMS network.

[0058] In one possible implementation, the core network device obtains network information of the first IMS network, including: the core network device receiving the network information of the first IMS network from the user equipment through a session establishment process; the fourth information indicating that the establishment of a connection between the user equipment and the first IMS network is not supported, the fourth information including session establishment rejection information.

[0059] In one possible implementation, the network information includes one or more of the following: the service provider's identifier, the network identifier, the network domain name, the address information of the proxy calling network element, and the data network name.

[0060] In one possible implementation, the fourth information includes one or more of the following: session establishment acceptance information, session establishment rejection information, service provider identifier, network identifier, network domain name, address information of the proxy calling network element, and data network name. In another possible implementation, the session establishment acceptance information may include message type information and / or parameter information of the session establishment acceptance message. The session establishment rejection information may include message type information and / or parameter information of the session establishment rejection message.

[0061] In one possible implementation, the fourth information may be network information of a second IMS network, wherein the second IMS network may be an IMS network selected by the core network device from one or more IMS networks connected to a non-public network accessed by the user equipment. In another possible implementation, the fourth information includes one or more of the following: the service provider identifier, network identifier, network domain name, address information of the proxy calling network element, and data network name of the second IMS network. The second IMS network may be the same as or different from the first IMS network. When the second IMS network is the same as the first IMS network, the network information of the second IMS network can be used to implicitly indicate support for establishing a connection between the user equipment and the first IMS network. When the second IMS network is different from the first IMS network, the network information of the second IMS network can be used to implicitly indicate that establishing a connection between the user equipment and the first IMS network is not supported.

[0062] In one possible implementation, the fourth information may be indication information, which may be used to indicate whether or not to support establishing a connection between the user equipment and the first IMS network.

[0063] For example, the indication information can be a single bit, multiple bits, or a string. When the indication information is a single bit, a value of 1 indicates support for establishing a connection between the user equipment and the first IMS network, and a value of 0 indicates that establishing a connection between the user equipment and the first IMS network is not supported. Alternatively, when the indication information is a single bit, a value of 0 indicates support for establishing a connection between the user equipment and the first IMS network, and a value of 1 indicates that establishing a connection between the user equipment and the first IMS network is not supported. When the indication information is multiple bits, one type of multiple bits can indicate support for establishing a connection between the user equipment and the first IMS network, and another type of multiple bits can indicate that establishing a connection between the user equipment and the first IMS network is not supported. When the indication information is a string, one type of string can indicate support for establishing a connection between the user equipment and the first IMS network, and another type of string can indicate that establishing a connection between the user equipment and the first IMS network is not supported.

[0064] When the fourth information indicates support for establishing a connection between the user equipment and the first IMS network, the user equipment can obtain the address information of the proxy call network element corresponding to the first IMS network from the domain name system server or session management network element, and then establish a connection with the proxy call network element based on the address information, thereby obtaining the IMS service of the first IMS network.

[0065] The technical effects achievable in the sixth aspect above can be referred to the description of the beneficial effects in the fifth aspect above, and will not be repeated here.

[0066] Seventhly, this application provides a communication method that can be executed by a user equipment or by a component (such as a chip or circuit) in the user equipment.

[0067] In one possible implementation, the method is performed by a user equipment (UE), and includes: the UE acquiring network information of one or more IMS networks, wherein the one or more IMS networks are connected to a non-public network accessed by the UE; the UE determining that one or more IMS networks include a first IMS network to which the UE requests a connection; and the UE establishing a connection with the first IMS network based on the network information of the first IMS network. Here, establishing a connection between the UE and the first IMS network can be understood as the UE establishing a session with the data network to which the first IMS network belongs, or as the UE establishing an IP connection with a call agent network element of the first IMS network, or simply establishing an IP connection between the UE and the first IMS network.

[0068] In the above technical solution, the user equipment obtains network information of one or more IMS networks connected to the non-public network accessed by the user equipment from the core network equipment. Based on the network information of the one or more IMS networks, the user equipment determines whether the one or more IMS networks include a first IMS network. This is equivalent to the user equipment determining whether there is an IMS network that can provide IMS services to the user equipment among the one or more IMS networks connected to its non-public network. If the user equipment determines that there is an IMS network that can provide IMS services to the user equipment among the one or more IMS networks connected to its non-public network, the user equipment can request to obtain IMS services.

[0069] In this approach, if a user equipment (UE) finds an IMS network among one or more non-public networks connected to it that can provide IMS services, it initiates a request to obtain IMS services. This reduces the likelihood of a UE blindly initiating a request to obtain IMS services due to uncertainty about the existence of the requested IMS network, which could lead to a rejection message. Since both initiating the request and receiving the rejection message consume signaling and network resources, this approach further reduces signaling consumption and network resource consumption.

[0070] In one possible implementation, the method further includes: the user equipment sending IMS capability information to the core network equipment, the IMS capability information being used to indicate that the user equipment supports establishing a connection with the IMS network, or the IMS capability information being used to indicate that the user equipment supports obtaining IMS services.

[0071] In one possible implementation, the IMS capability information includes network information of the first IMS network. For example, the IMS capability information is the network information of the first IMS network. The network information of the first IMS network may include one or more of the following: the service provider identifier, network identifier, network domain name, data network name, and address information of the proxy call network element. In this implementation, the user equipment implicitly indicates to the core network equipment that the user equipment supports obtaining IMS services, and the user equipment requests or supports establishing a connection with the first IMS network.

[0072] In one possible implementation, the IMS capability information can be indication information. For example, the indication information can indicate that the user equipment supports obtaining IMS services, or it can indicate that the user equipment does not support obtaining IMS services. For example, the indication information can be a single bit, multiple bits, or a string. When the indication information is a single bit, a value of 1 indicates that the user equipment supports obtaining IMS services, and a value of 0 indicates that the user equipment does not support obtaining IMS services. Alternatively, when the indication information is a single bit, a value of 0 indicates that the user equipment supports obtaining IMS services, and a value of 1 indicates that the user equipment does not support obtaining IMS services. When the indication information is multiple bits, one type of multiple bits can indicate that the user equipment does not support obtaining IMS services, and another type of multiple bits can indicate that the user equipment supports obtaining IMS services. When the indication information is a string, one type of string can indicate that the user equipment does not support obtaining IMS services, and another type of string can indicate that the user equipment supports obtaining IMS services.

[0073] In one possible implementation, the user equipment sends IMS capability information to the core network equipment, including: the user equipment sends the IMS capability information to the core network equipment through a registration process or a session establishment process.

[0074] In the above technical solution, the user equipment can send IMS capability information to the core network equipment. Correspondingly, the core network equipment can respond to the IMS capability information by sending network information of one or more IMS networks to the user equipment. Thus, the user equipment can determine whether it can request IMS service based on the network information of one or more IMS networks.

[0075] In one possible implementation, the user equipment (UE) obtains network information of one or more IMS networks, including: the UE obtains the network information of the one or more IMS networks from the core network equipment through a session establishment process; the UE establishes a connection with the first IMS network based on the network information of the first IMS network, including: the UE obtains the address information of the proxy call network element corresponding to the first IMS network; the UE establishes a connection with the proxy call network element based on the address information. In another possible implementation, the UE can obtain the address information of the proxy call network element corresponding to the first IMS network from a Domain Name System (DNS) server or a session management network element, and then establish a connection with the proxy call network element based on the address information to obtain the IMS service of the first IMS network.

[0076] In the above technical solution, the user equipment can obtain network information of one or more IMS networks from the core network equipment during the session establishment process. This allows the user equipment to determine whether to request a connection with the first IMS network based on its network information during session establishment. This method helps reduce signaling overhead and network resource consumption. The core network equipment can be a session management network element.

[0077] In one possible implementation, the user equipment obtains network information of one or more IMS networks, including: the user equipment obtains the network information of the one or more IMS networks from the core network device through a registration process; the user equipment establishes a connection with the first IMS network based on the network information of the first IMS network, including: the user equipment sends a session establishment request to the core network device based on the network information of the first IMS network, the session establishment request being used to establish a connection between the user equipment and the first IMS network.

[0078] In the above technical solution, the user equipment can obtain network information of one or more IMS networks from the core network equipment during the registration process. Thus, the user equipment can determine whether to send a session establishment request to the core network equipment based on the network information of the first IMS network through the registration process. This method can help reduce signaling overhead and network resource consumption. The core network equipment can be an access and mobility management network element.

[0079] In one possible implementation, the network information of the one or more IMS networks is included in the broadcast message of the access network device. In the above technical solution, the access network device can carry the network information of one or more IMS networks in the broadcast message and broadcast it to the user equipment, so that the user equipment can determine whether to request to establish a connection with the first IMS network based on the network information of one or more IMS networks. This broadcast message can be sent periodically, before, during, or after the user equipment's registration process.

[0080] In one possible implementation, the network information includes one or more of the service provider's identifier, network identifier, network domain name, data network name, and address information of the proxy calling network element. In another possible implementation, the user equipment can obtain one or more of the service provider's identifier, network identifier, network domain name, data network name, and address information of the IMS network connected to the non-public network accessed by the user equipment from the core network equipment. This allows the user equipment to determine whether to initiate a request to obtain IMS services based on the information from the core network equipment.

[0081] Eighthly, this application provides a communication method that can be executed by a core network device or by a component (such as a chip or circuit) in the core network device.

[0082] In one possible implementation, the method is performed by a core network device, and includes: the core network device acquiring network information of one or more IMS networks, which are connected to a non-public network accessed by the user equipment; and the core network device sending the network information of the one or more IMS networks to the user equipment. In one possible implementation, the core network device may be an access and mobility management network element or a session management network element.

[0083] When the core network device is an access and mobility management (IMS) network element, it can obtain network information of one or more IMS networks from the session management (SMA) network element, or the IMS network element may have the network information of one or more IMS networks pre-configured within it. When the core network device is a session management (SMA) network element, it can obtain network information of one or more IMS networks from the unified data management (UDM) network element, or the session management (SMA) network element may have the network information of one or more IMS networks pre-configured within it.

[0084] In one possible implementation, the core network device further includes: receiving IMS capability information of the user equipment from the user equipment, wherein the IMS capability information is used to indicate that the user equipment supports establishing a connection with the IMS network, or the IMS capability information is used to indicate that the user equipment supports obtaining IMS services.

[0085] In one possible implementation, the IMS capability information includes network information of the first IMS network. For example, the IMS capability information is the network information of the first IMS network. The network information of the first IMS network may include one or more of the following: the service provider identifier, network identifier, network domain name, data network name, and address information of the proxy call network element. In this implementation, the user equipment implicitly indicates to the core network equipment that the user equipment supports obtaining IMS services, and the user equipment requests to establish a connection with the first IMS network.

[0086] In one possible implementation, the IMS capability information can be indication information, which can indicate whether the user equipment supports or does not support obtaining IMS services. For example, the indication information can be a single bit, multiple bits, or a string. When the indication information is a single bit, a value of 1 indicates that the user equipment supports obtaining IMS services, and a value of 0 indicates that the user equipment does not support obtaining IMS services. Alternatively, when the indication information is a single bit, a value of 0 indicates that the user equipment supports obtaining IMS services, and a value of 1 indicates that the user equipment does not support obtaining IMS services. When the indication information is multiple bits, one type of multiple bits can indicate that the user equipment does not support obtaining IMS services, and another type of multiple bits can indicate that the user equipment supports obtaining IMS services. When the indication information is a string, one type of string can indicate that the user equipment does not support obtaining IMS services, and another type of string can indicate that the user equipment supports obtaining IMS services.

[0087] In one possible implementation, the core network device receives the IMS capability information of the user equipment from the user equipment, including: the core network device receiving the IMS capability information of the user equipment from the user equipment through a registration process or a session establishment process.

[0088] In one possible implementation, the core network device sends network information of one or more IMS networks to the user equipment, including: the core network device sending the network information of the one or more IMS networks to the user equipment through a registration process; if the one or more IMS networks include the first IMS network, the method further includes: the core network device receiving a session establishment request message from the user equipment; the session establishment request message is used to establish a connection between the user equipment and the first IMS network.

[0089] In one possible implementation, the network information includes one or more of the following: service provider identifier, network identifier, network domain name, data network name, and address information of the proxy call element.

[0090] The technical effects achievable in the eighth aspect above can be referred to the description of the beneficial effects in the seventh aspect above, and will not be repeated here.

[0091] Ninthly, this application provides a communication method, which can be executed by a user equipment or by a component (such as a chip or circuit) within the user equipment. In one possible implementation, the method is executed by the user equipment and includes: the user equipment obtaining network information of one or more IMS networks from the core network device through a session establishment process, wherein the one or more IMS networks are connected to a non-public network accessed by the user equipment; the user equipment determining that the one or more IMS networks do not include a first IMS network to which the user equipment requests a connection; and the user equipment sending a session modification request or a session release request to the core network device.

[0092] In the above technical solution, the user equipment (UE) obtains network information from the core network equipment regarding one or more IMS networks connected to the non-public network it accesses. Based on this network information, the UE determines whether the one or more IMS networks include a first IMS network. This is equivalent to the UE determining whether an IMS network capable of providing IMS services exists among the one or more IMS networks connected to its non-public network. If not, the UE can send a session modification request or a session release request to the core network equipment. In one possible implementation, the session modification request may include message type information and / or parameter information of the session modification request message. Similarly, the session release request may include message type information and / or parameter information of the session release request message. In this approach, if an IMS network capable of providing IMS services exists among the one or more IMS networks connected to its non-public network, the UE will initiate a process to request IMS services. This avoids the UE being unable to obtain IMS services after initiating the request, thus reducing signaling overhead and network resource consumption.

[0093] Tenthly, this application provides a communication method, which can be executed by a core network device or by a component (such as a chip or circuit) within the core network device. In one possible implementation, the core network device acquires network information of one or more IMS networks, which are connected to a non-public network accessed by the user equipment. The core network device sends the network information of the one or more IMS networks to the user equipment through a session establishment process. When the one or more IMS networks do not include the first IMS network, the core network device receives session modification request information or session release request information from the user equipment. In one possible implementation, the session modification request information may include message type information and / or parameter information of the session modification request message. The session release request information may include message type information and / or parameter information of the session release request message.

[0094] The technical effects achievable in the tenth aspect above can be referred to the description of the beneficial effects in the ninth aspect above, and will not be repeated here.

[0095] Eleventhly, embodiments of this application provide a communication device that can have the function of implementing the session management network element in the first aspect or any possible implementation of the first aspect. The device can be a session management network element or a chip included in the session management network element.

[0096] The device may also have the functionality of a user equipment as described in the second aspect or any possible implementation of the second aspect. The device may be a user equipment or a chip included in the user equipment.

[0097] The device may also have the function of implementing the strategy control network element in the third aspect or any possible implementation of the third aspect. The device may be the strategy control network element or the chip included in the strategy control network element.

[0098] The device may also have the function of implementing the target agent calling network element in the fourth aspect or any possible implementation of the fourth aspect. The device may be the target agent calling network element or a chip included in the target agent calling network element.

[0099] The device may also have the functionality of a user equipment as described in the fifth aspect or any possible implementation of the fifth aspect. The device may be a user equipment or a chip included in the user equipment.

[0100] The device may also have the function of implementing the core network equipment in the sixth aspect or any possible implementation of the sixth aspect. The device may be the core network equipment or a chip included in the core network equipment.

[0101] The device may also have the functionality of a user equipment as described in the seventh aspect or any possible implementation of the seventh aspect. The device may be a user equipment or a chip included in the user equipment.

[0102] The device may also have the function of implementing the core network equipment in the eighth aspect or any possible implementation of the eighth aspect. The device may be the core network equipment or a chip included in the core network equipment.

[0103] The functions of the aforementioned communication device can be implemented by hardware or by hardware executing corresponding software. The hardware or software includes one or more modules, units, or means corresponding to the aforementioned functions.

[0104] In one possible implementation, the device includes a processing module and a transceiver module. The processing module is configured to support the device in performing functions corresponding to the session management network element in the first aspect or any possible implementation thereof, or performing functions corresponding to the user equipment in the second aspect or any possible implementation thereof, or performing functions corresponding to the policy control network element in the third aspect or any possible implementation thereof, or performing functions corresponding to the target agent call network element in the fourth aspect or any possible implementation thereof. The transceiver module supports communication between the device and other communication devices. The communication device may also include a storage module coupled to the processing module, which stores the necessary program instructions and data of the device.

[0105] As an example, the processing module can be a processor, the communication module can be a transceiver, and the storage module can be a memory. The memory can be integrated with the processor or set up separately from the processor.

[0106] In another possible implementation, the device includes a processor and may also include a memory. The processor is coupled to the memory and can be used to execute computer program instructions stored in the memory to cause the device to perform the methods in the first aspect or any possible implementation thereof, the second aspect or any possible implementation thereof, the third aspect or any possible implementation thereof, the fourth aspect or any possible implementation thereof, the fifth aspect or any possible implementation thereof, the sixth aspect or any possible implementation thereof, the seventh aspect or any possible implementation thereof, and the eighth aspect or any possible implementation thereof.

[0107] Optionally, the device further includes a communication interface, with the processor coupled to the communication interface. When the device is a session management network element, user equipment, policy control network element, or target agent call network element, the communication interface can be a transceiver or an input / output interface; when the device is a chip contained within a session management network element, user equipment, policy control network element, or target agent call network element, the communication interface can be the chip's input / output interface. Optionally, the transceiver can be a transceiver circuit, and the input / output interface can be an input / output circuit.

[0108] In a twelfth aspect, embodiments of this application provide a chip system, including: a processor coupled to a memory, the memory being used to store programs or instructions, wherein when the program or instructions are executed by the processor, the chip system implements the methods of the first aspect or any possible implementation of the first aspect, or implements the methods of the second aspect or any possible implementation of the second aspect, or implements the methods of the third aspect or any possible implementation of the third aspect, or implements the methods of the fourth aspect or any possible implementation of the fourth aspect, executes the methods of the fifth aspect or any possible implementation of the fifth aspect, executes the methods of the sixth aspect or any possible implementation of the sixth aspect, executes the methods of the seventh aspect or any possible implementation of the seventh aspect, and executes the methods of the eighth aspect or any possible implementation of the eighth aspect.

[0109] Optionally, the chip system also includes an interface circuit for exchanging code instructions with the processor.

[0110] Optionally, the chip system may include one or more processors, which can be implemented in hardware or software. When implemented in hardware, the processor may be a logic circuit, integrated circuit, etc. When implemented in software, the processor may be a general-purpose processor that reads software code stored in memory.

[0111] Optionally, the chip system may contain one or more memories. These memories may be integrated with the processor or disposed separately. For example, the memory may be a non-transitory processor, such as a read-only memory (ROM), which may be integrated with the processor on the same chip or disposed on separate chips.

[0112] In a thirteenth aspect, embodiments of this application provide a computer-readable storage medium having a computer program or instructions stored thereon. When the computer program or instructions are executed, the computer performs the method in the first aspect or any possible implementation thereof, or performs the method in the second aspect or any possible implementation thereof, or performs the method in the third aspect or any possible implementation thereof, or performs the method in the fourth aspect or any possible implementation thereof, performs the method in the fifth aspect or any possible implementation thereof, performs the method in the sixth aspect or any possible implementation thereof, performs the method in the seventh aspect or any possible implementation thereof, or performs the method in the eighth aspect or any possible implementation thereof.

[0113] In a fourteenth aspect, embodiments of this application provide a computer program product that, when a computer reads and executes the computer program product, causes the computer to execute the method in the first aspect or any possible implementation of the first aspect, or execute the method in the second aspect or any possible implementation of the second aspect, or execute the method in the third aspect or any possible implementation of the third aspect, or execute the method in the fourth aspect or any possible implementation of the fourth aspect, or execute the method in the fifth aspect or any possible implementation of the fifth aspect, or execute the method in the sixth aspect or any possible implementation of the sixth aspect, or execute the method in the seventh aspect or any possible implementation of the seventh aspect, or execute the method in the eighth aspect or any possible implementation of the eighth aspect.

[0114] In a fifteenth aspect, embodiments of this application provide a communication system, which includes a session management network element for performing the first aspect or any possible implementation thereof, and a user equipment for performing the second aspect or any possible implementation thereof. Optionally, the communication system further includes a policy control network element for performing the third aspect or any possible implementation thereof.

[0115] Alternatively, the communication system includes a session management network element for performing the first aspect or any possible implementation of the first aspect, a user equipment for performing the second aspect or any possible implementation of the second aspect, a policy control network element for performing the third aspect or any possible implementation of the third aspect, and a target proxy call network element for performing the fourth aspect or any possible implementation of the fourth aspect.

[0116] Alternatively, the communication system includes user equipment for performing the fifth aspect or any possible implementation of the fifth aspect, and core network equipment for performing the sixth aspect or any possible implementation of the sixth aspect.

[0117] Alternatively, the communication system may include user equipment for performing the seventh aspect or any possible implementation thereof, and core network equipment for performing the eighth aspect or any possible implementation thereof.

[0118] The technical effects that can be achieved in any of the eleventh to fifteenth aspects mentioned above can be referred to the descriptions of the technical effects that can be achieved in any of the first to ninth aspects mentioned above, and will not be repeated here. Attached Figure Description

[0119] Figure 1 This application provides an exemplary system architecture for a non-public network.

[0120] Figure 2a A schematic diagram illustrating the connection relationship between a non-public network and an IMS network provided for this application;

[0121] Figure 2b A schematic diagram illustrating the connection relationship between another non-public network and an IMS network provided for this application;

[0122] Figure 3 A schematic diagram illustrating the process of establishing a session between a user equipment and an IMS network, as provided in this application;

[0123] Figure 4 A schematic diagram illustrating another connection relationship between a non-public network and an IMS network provided for this application;

[0124] Figure 5a A schematic diagram illustrating a local user server deployed in a non-public network, as provided in this application;

[0125] Figure 5b A schematic diagram illustrating a proxy call network element deployed in a non-public network with a local user server and no service provider attribute, provided for this application;

[0126] Figure 6 A flowchart illustrating a communication method provided in this application;

[0127] Figure 7 A flowchart illustrating a first session connection method provided as an example in this application;

[0128] Figure 8 A flowchart illustrating a second session connection method provided exemplarily in this application;

[0129] Figure 9 A flowchart illustrating a third session connection method provided exemplarily in this application;

[0130] Figure 10 A flowchart illustrating the fourth session connection method provided exemplarily in this application;

[0131] Figure 11 A flowchart illustrating a first method for establishing a connection with an IMS network, provided as an example in this application;

[0132] Figure 12 A flowchart illustrating a second method for establishing a connection with an IMS network, provided as an example in this application;

[0133] Figure 13 A flowchart illustrating a third method for establishing a connection with an IMS network, provided as an example in this application;

[0134] Figure 14A flowchart illustrating a fourth method for establishing a connection with an IMS network, provided as an example in this application;

[0135] Figure 15 A schematic diagram of the structure of a communication device provided in this application;

[0136] Figure 16 A schematic diagram of another communication device provided in this application. Detailed Implementation

[0137] For ease of description, the relevant technologies and / or terms involved in this application are explained below.

[0138] I. The main functional entities involved in the IMS network are as follows:

[0139] The Home Subscriber Server (HSS) serves as the database for storing user information within IMS. It primarily stores user authentication information, specific information about subscribed users, dynamic information about subscribed users, network policy rules, and device identifier register information, used for mobility management and user service data management. It is a logical entity, but physically it can consist of multiple physical databases.

[0140] The call session control function (CSCF) network element is a core component of IMS, primarily used for packet-switched session initiation protocol (SIP) control. In IMS, the CSCF network element is responsible for processing user multimedia sessions and can be viewed as a SIP server within the IETF architecture. Based on their respective main functions, the CSCF network element is divided into proxy-call session control function (P-CSCF) network elements, interrogation-call session control function (I-CSCF) network elements, and serving-call session control function (S-CSCF) network elements. These three functions can be physically separated or independent. In this application, the proxy-call session control function network element can also be referred to as the proxy call network element, the interrogation-call session control function network element as the interrogation call network element, and the serving-call session control function network element as the serving call network element.

[0141] The Multimedia Resource Function (MRF) network element primarily handles multi-party calls and multimedia conferencing. It consists of a Multimedia Resource Function Controller (MRFC) and a Multimedia Resource Function Processor (MRFP), which respectively control and carry media streams. The MRFC parses session initiation protocol signaling received from the Service Call Session Control Function (SCECF) network element and uses Media Gateway Control Protocol (MTP) instructions to control the MRFP to perform the corresponding media stream encoding / decoding, conversion, mixing, and playback functions.

[0142] Gateway functions include the IMS breakout gateway control function (BGCF), media gateway control function (MGCF), IMS media gateway (IMS MGW), and signaling gateway (SGW).

[0143] II. Standalone non-public networks (or independent private networks or non-public networks) are networks that do not rely on public land mobile networks (PLMNs) and are operated by dedicated non-public network operators. Network elements in a non-public network serve user equipment within that network, and control plane signaling and user plane data are typically not transmitted to external networks, achieving a certain level of security and privacy.

[0144] For example, such as Figure 1 The system architecture of a non-public network provided in this application includes the following devices or network elements:

[0145] User equipment, also known as terminal equipment, mobile station (MS), mobile terminal (MT), etc., is a device that provides voice and / or data connectivity to users. For example, user equipment can include handheld devices with wireless connectivity, in-vehicle devices, etc. Currently, user equipment can include: mobile phones, tablets, laptops, PDAs, mobile internet devices (MIDs), wearable devices, virtual reality (VR) devices, augmented reality (AR) devices, wireless terminals in industrial control, wireless terminals in self-driving, wireless terminals in remote medical surgery, wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in smart cities, or wireless terminals in smart homes, etc. Figure 1 The user equipment described herein is shown as a UE, and is for illustrative purposes only and is not intended to limit the user equipment.

[0146] Access network (AN) devices, also known as access network elements, are used to provide wireless access services to user equipment. These access network devices are the equipment in the communication system that connects the user equipment to the wireless network. The access network device is a node in the wireless access network, also known as a base station, or a radio access network (RAN) node (or device). Examples of current access network devices include: gNB, transmission reception point (TRP), evolved Node B (eNB), radio network controller (RNC), Node B (NB), basestation controller (BSC), base transceiver station (BTS), home base station (e.g., home evolved Node B, or home Node B, HNB), base band unit (BBU), or wireless fidelity (Wi-Fi) access point (AP), etc.

[0147] Application function network elements primarily interact with the 3rd Generation Partnership Project (3GPP) core network to provide services, influencing service flow routing, access network capability openness, and policy control. For example, in 5G, the application function network element can be an application function (AF) network element. In future communications, such as 6G, the application function network element may still be an AF network element, or may have other names; this application does not limit this. When the application function network element is an AF network element, the AF network element can provide NAF services.

[0148] Network open elements (NAIs) enable 3GPP to securely provide network service capabilities to third-party AFs (e.g., service capability servers (SCS), application servers (AS)). For example, in 5G, the NAI can be a Network Exposure Function (NEF) element. In future communication systems, such as 6G, the NAI can still be a NEF element, or have other names; this application does not limit this. When the NAI is a NEF, it can provide NEF services to other network function elements.

[0149] A unified data management network element can be used to manage the user equipment's subscription data, registration information related to the user equipment, etc. For example, in 5G, the unified data management network element can be a unified data management (UDM) network element. In future communication systems, such as 6G, the unified data management function network element can still be a UDM network element, or it may have other names; this application does not limit this. When the unified data management function network element is a UDM network element, the UDM network element can provide Nudm services.

[0150] The access and mobility management network element can be used to manage the access control and mobility of the user equipment. In practical applications, it includes the access and mobility management functions of the mobility management entity (MME) in the Long Term Evolution (LTE) network framework, and adds access management functions. Specifically, it can be responsible for user equipment registration, mobility management, tracking area update procedures, reachability detection, selection of session management network elements, and mobility state transition management. For example, in 5G, the access and mobility management network element can be an access and mobility management function (AMF) network element. In future communications, such as 6G, the access and mobility management network element can still be an AMF network element, or it can have other names; this application does not limit this. When the access and mobility management network element is an AMF network element, the AMF can provide Namf services.

[0151] A session management network element can be used to manage the user equipment's sessions (including session establishment, modification, and release), select and reselect user plane function network elements, allocate the user equipment's Internet Protocol (IP) address, and control quality of service (QoS). For example, in 5G, the session management network element can be a session management function (SMF) network element. In future communication systems, such as 6G, the session management network element can still be an SMF network element, or it may have other names; this application does not limit this. When the session management network element is an SMF network element, the SMF can provide NSMF services.

[0152] User plane function (UPF) network elements are responsible for forwarding and receiving user data in user equipment. They can receive user data from the data network and transmit it to the user equipment via access network equipment; UPF network elements can also receive user data from user equipment via access network equipment and forward it to the data network. The transmission resources and scheduling functions providing services to user equipment within the UPF network element are managed and controlled by the session management function network element.

[0153] In actual deployments, network elements in non-public networks can be co-located. For example, the access and mobility management network element can be co-located with the session management network element; the session management network element can be co-located with the user plane network element. When two network elements are co-located, the interaction between these two network elements provided in the embodiments of this application becomes an internal operation of the co-located network element or can be omitted.

[0154] The solutions provided in this application can be applied not only to non-public networks, but also to neutral networks, non-3GPP access networks, and other networks. This application does not impose any limitations.

[0155] In existing technologies, the connection relationship between non-public networks and IMS networks can be referenced as follows: Figure 2aA non-public network connects only to an IMS network, while an IMS network can connect to one or more non-public networks. For example, the IP multimedia private identity (IMPI) and IP multimedia public identity (IMPU) of a user equipment (UE) in a non-public network are based on the UE's subscription permanent identifier (SUPI) in the non-public network. When the IMS network receives IMS messages from UEs in different non-public networks, it can determine which non-public network the UE originates from based on these IPI and SUPI.

[0156] Furthermore, such as Figure 2b This example illustrates a structural diagram of an IMS network connected to a non-public network. The non-public network includes user equipment, access network equipment, access and mobility management network elements, user plane function network elements, session management network elements, policy control network elements, and unified data management network elements. The IMS network includes a home subscriber server, proxy call network elements, and query / service call network elements. Only one IMS network can be connected to each non-public network.

[0157] Combination such as Figure 2b Mid-architecture diagram, such as Figure 3 This application provides a schematic diagram of the process for establishing a session between a user equipment and an IMS network.

[0158] Step 301: The user equipment requests the access and mobility management network element to establish a protocol data unit (PDU) session.

[0159] For example, a user equipment (UE) sends a non-access stratum (NAS) message to the access and mobility management network element. This NAS message carries parameters such as a session identifier (PDU Session ID), a UE-Requested data network name (UE Requested DNN), and single network slice selection assistance information (S-NSSAI). The UE Requested DNN can be determined by the UE based on its service provider; for example, if the UE corresponds to service provider A, then the UE Requested DNN is the name of the IMS network provided by service provider A.

[0160] Step 302: Select the session management network element for access and mobility management.

[0161] Step 303: The access and mobility management network element requests the session management network element to establish a PDU session.

[0162] For example, the access and mobility management network element sends a PDU session creation session context request message to the session management network element. This PDU session creation session context request message carries parameters such as SUPI, UE Requested DNN, and PDU Session ID.

[0163] Optionally, in step 304, the session management network element obtains session management subscription data from the unified data management network element.

[0164] Step 305: The session management network element sends a PDU session creation session context response message to the access and mobility management network element.

[0165] Optional, step 306, PDU session authentication or authorization process.

[0166] Step 307: The session management network element establishes a session policy association with the policy control network element. Specifically, if dynamic policy control and charging (PCC) rules are required, the session management network element selects the policy control network element and establishes a session policy association with that policy control network element.

[0167] Step 308: Select the user plane function network element for session management. Step 308 is optional.

[0168] Step 309: The session management network element performs session policy association modification to the policy control network element. In this step, the session management network element sends the IP address assigned to the user equipment to the policy control network element.

[0169] Step 309 is executed if step 307 is executed.

[0170] Step 310: The session management network element establishes an N4 connection with the user plane function network element.

[0171] Step 311: The session management network element sends an N1N2 message (Namf_Communication_N1N2Message transfer) to the access and mobility management network element. The N1N2 message carries information such as the tunnel endpoint identifier of the user plane function network element. This information is sent to the access network device to inform it of the destination of the uplink data. If the PDU session is for IMS, the session management network element will also include the address information of the proxy calling network element in this N1N2 message.

[0172] Step 312: The access and mobility management network element sends the address information of the aforementioned proxy call network element to the user equipment.

[0173] For example, the access and mobility management network element sends a NAS message to the user equipment. This NAS message carries the address information of the aforementioned proxy call network element.

[0174] Step 313: The user equipment requests to establish a connection with the proxy calling network element based on the address of the received proxy calling network element.

[0175] For example, the user equipment sends SIP signaling (also known as IMS signaling or IMS message) to the proxy call network element. This SIP signaling is used to request the establishment of a connection with the IMS network. The destination address of this SIP signaling is the address of the proxy call network element received by the user equipment.

[0176] To enable user equipment from different service providers to establish session connections with the corresponding IMS network provided by their service providers within a non-public network, such as... Figure 4 Another system architecture provided as an example of this application is a system architecture in which a non-public network can connect to multiple IMS networks.

[0177] For example, such as Figure 4In this embodiment, non-public networks connect IMS network 1, IMS network 2, and IMS network 3 respectively. IMS network 1 is provided by service provider 1, IMS network 2 by service provider 2, and IMS network 3 by service provider 3. Specifically, service provider 1, service provider 2, and service provider 3 are respectively identified by the following identification information: service provider identifier 1 (SPID1), service provider identifier 2 (SP ID2), and service provider identifier 3 (SP ID3). IMS network 1, IMS network 2, and IMS network 3 are respectively identified by the following identification information: IMS network identifier 1 (IMS ID1), IMS network identifier 2 (IMS ID2), and IMS network identifier 3 (IMS ID3). All embodiments of this application can be combined with... Figure 4 For example.

[0178] It should also be noted that an IMS network can still continue to connect to one or more non-public networks.

[0179] When a user equipment (UE) in a non-public network requests to connect to an IMS network, the non-public network needs to determine which IMS network the UE is requesting to connect to (hereinafter referred to as the target IMS network). For example, such as... Figure 4 If the user equipment belongs to service provider 1, when the user equipment requests to connect to the IMS network, the non-public network determines that the target IMS network is IMS network 1, and then the non-public network establishes a session connection between the user equipment and IMS network 1.

[0180] In an optional way, such as Figure 5a As shown, a local user server (IMS HSS) for an IMS network can be deployed in a non-public network. This local user server stores the subscription data of user equipment in the IMS network. When a user equipment initiates a PDU session establishment request message, the non-public network, through the unified data management network element and the local user server, determines the service provider information of the target IMS network that the user equipment wants to connect to, thereby identifying the target IMS network and the proxy call network element in the target IMS network. The non-public network then establishes a connection between the user plane function network element and the proxy call network element, thus completing the PDU session establishment.

[0181] In another alternative, such as Figure 5bAs shown, a local user server and a proxy call network element without service provider attributes can be deployed in a non-public network. The local user server stores the user equipment's subscription data in the IMS network, and the user plane function network element connects to the proxy call network element via the N6 interface. When a user equipment initiates a PDU session establishment request message, the proxy call network element can query the local user server to obtain the user equipment's service provider information, thereby determining the target IMS network and the query call network element in the target IMS network based on the user equipment's service provider information. When the proxy call network element receives an IMS message from the user equipment, it can forward the IMS message to the query call network element in the target IMS network.

[0182] like Figure 5a and Figure 5b In both cases, additional functional network elements need to be added in non-public networks, increasing deployment costs.

[0183] Based on this, this application provides a communication method that identifies a target IMS network from multiple IMS networks connected to a non-public network and establishes a session connection between the user equipment and the target IMS network.

[0184] Furthermore, the method provided in this application helps save deployment costs. With a corresponding proxy call network element deployed in each IMS network, there is no need to add a local user server in a non-public network. (Refer to...) Figure 5a It allows you to identify the target IMS network from multiple IMS networks without deploying a local user server in a non-public network.

[0185] Alternatively, when deploying a proxy call network element without service provider attributes in a non-public network, it is not necessary to add a local user server in the non-public network, as described above. Figure 5b It allows you to identify the target IMS network from multiple IMS networks without deploying a local user server in a non-public network.

[0186] It should be understood that the communication method provided in this application can be applied to two architectures:

[0187] Architecture 1 involves deploying a corresponding proxy call network element in each IMS network. Architecture 1 can be referenced from [reference needed]. Figure 5a Furthermore, there is no need to deploy a local user server in non-public networks.

[0188] Architecture 2 involves deploying proxy call network elements without service provider attributes in a non-public network. Architecture 2 can be referenced from [reference needed]. Figure 5b Furthermore, there is no need to deploy a local user server in non-public networks.

[0189] For reference Figure 6The flowchart shown is explained below. This flowchart involves a non-public network and multiple IMS networks connected to the non-public network. The non-public network determines a target IMS network from among the multiple IMS networks, where the target IMS network is provided by the user equipment's service provider (which may be referred to as the target service provider).

[0190] Furthermore, the non-public network includes session management network elements, access and mobility management network elements, policy control network elements, user equipment, and access network equipment, while the IMS network includes interrogation call network elements. Based on the above architecture one and architecture two, the proxy call network element can be located in either the non-public network or the IMS network.

[0191] Step 601: The user equipment sends the first information to the session management network element.

[0192] The first information is used to indicate the target IMS network that the user equipment requests to connect to.

[0193] The first piece of information can be sent directly from the user equipment to the session management network element, or it can be sent from the user equipment to the session management network element via the access and mobility management network element.

[0194] The first information can be sent by the user equipment (UE) when requesting to establish a session connection, or it can be sent by the UE before requesting to establish a session connection. For example, the UE sends a PDU session establishment request message (NAS message) to the access and mobility management network element (AMI), which includes the first information. The AMI selects a session management network element and then sends the first information to that session management network element. In one possible implementation, the AMI sends a PDU session creation session context request message to the session management network element, which includes the first information.

[0195] The first information may include the identification information of the target service provider and / or the first call information. Specifically, the identification information of the target service provider may be any information that can be used to characterize the service provider providing the target IMS network service, such as the target service provider identifier, the target operator identifier, or the target operator network identifier. The first call information is used to indicate the target agent call network element in the target IMS network; specifically, the first call information may be the address information of the target agent call network element in the target IMS network.

[0196] In the first optional implementation, the user equipment can send the identification information of the target service provider as the first information to the session management network element.

[0197] For example, the user equipment may first obtain a first set, which includes the identification information of the service providers to which each of the multiple IMS networks connected to a non-public network belongs. The user equipment determines the identification information of the service provider requested by the user equipment (i.e., the identification information of the target service provider) from the first set and sends the identification information of the target service provider to the session management network element.

[0198] Combination Figure 4 For example, the first set includes SP ID1, SP ID2, and SP ID3. If the user equipment corresponds to service provider 1, the user equipment determines SP ID1 from the first set and sends SP ID1 to the session management network element.

[0199] In this optional implementation, the first set can be obtained by the user equipment from the access network equipment, or the access and mobility management network element, or the session management network element.

[0200] In the first example, the first set can be sent from the access network device to the user equipment. The access network device can send it based on a request from the user equipment or broadcast it to the user equipment. This first set can be carried in a radio resource control (RRC) message sent by the access network device to the user equipment, or in a medium access control control element (MAC CE), or in downlink control information (DCI).

[0201] In a second example, the user equipment (UE) may send a first request message to the access and mobility management (AM) network element (AM element) to request a first set. The AM element receives the first request message and sends a first response message containing the first set to the UE. Optionally, the AM element may obtain the first set from the session management (SMA) network element.

[0202] Optionally, the first request information may be carried in a NAS message sent by the user equipment to the access and mobility management network element. This first request information may be a separate NAS message or carried in an existing NAS message. The first response information may be carried in a NAS message sent by the access and mobility management network element to the user equipment. This first response information may be a separate NAS message or carried in an existing NAS message.

[0203] It should be noted that the purpose of the user equipment (UE) obtaining the first set is to determine whether a target IMS network providing services to the UE exists among multiple IMS networks connected to non-public networks. Therefore, if the UE determines that the identifier information of its service provider exists in the first set, it is determined that a target IMS network exists among the multiple IMS networks, and the UE can establish a session connection through the non-public network to obtain IMS services provided by that target IMS network. If the UE determines that the target IMS network does not exist among the multiple IMS networks, it is determined that it is impossible to establish a session connection through the non-public network to obtain IMS services provided by that target IMS network.

[0204] Furthermore, user equipment (UE) can also directly use its service provider's identification information as the primary information to determine, through a non-public network, whether the target IMS network exists among multiple IMS networks, and thus whether a session connection can be established between the UE and the target IMS network. Using the example above, the UE can send SP ID1 to the session management network element, where SP ID1 indicates IMS network 1 provided by service provider 1. If the non-public network determines, based on SP ID1, that IMS network 1 exists among multiple IMS networks, then a session connection is established between the UE and IMS network 1.

[0205] The first piece of information can be the data network name. It should be noted that in existing technologies, the data network name information corresponding to the IMS network is specifically "IMS," which does not include the target service provider's identification information. However, in this solution, the data network name information is enhanced, including the service provider's identification information, unlike the existing data network name information. The user equipment sends the data network name information to the session management network element, which can then obtain the target service provider's identification information based on the data network name information.

[0206] Optionally, the data network name information can be obtained by the user equipment from the access network equipment, or the access and mobility management network element, or the session management network element.

[0207] For example, the access network device broadcasts a second set, which includes data network name information corresponding to each of multiple IMS networks connected to a non-public network. The data network name information for each IMS network includes the identifier information of the service provider to which the IMS network belongs. The user equipment determines the data network name information from the second set based on its own service provider.

[0208] Combination Figure 4For example, the data network name information corresponding to IMS network 1, IMS network 2, and IMS network 3 are DNN1 (including SP ID1), DNN2 (including SP ID2), and DNN3 (including SP ID3), respectively. The second set broadcast by the access network device includes DNN1, DNN2, and DNN3. If the user equipment corresponds to service provider 1, the user equipment determines DNN1 from the second set and sends DNN1 to the session management network element.

[0209] In addition, the second set may further include the service provider corresponding to the DNN. For example, the second set includes (SP ID1 and DNN1), (SP ID2 and DNN2), and (SP ID3 and DNN3). The user equipment receives the second set, determines the DNN1 corresponding to SP ID1 from the second set according to the service provider 1 corresponding to the user equipment, and sends DNN1 to the session management network element.

[0210] For another example, the user equipment sends a second request message to the access and mobility management network element. The second request message is used to request the data network name information of the IMS network provided by the target service provider from the access and mobility management network element. The second request message includes the identification information of the target service provider.

[0211] Furthermore, the second request information may also include the identification information of the target service provider and the first indication information, wherein the first indication information is used to indicate that the second request information is a request message for requesting the data network name information of the IMS network provided by the target service provider.

[0212] The access and mobility management network element determines whether it has data network name information corresponding to the target service provider's identification information based on the target service provider's identification information in the second request information. If it does, it sends a second response message including the data network name information to the user equipment; if it does not, it obtains the data network name information from the session management network element and then sends a second response message including the data network name information to the user equipment.

[0213] In one specific implementation, the access and mobility management network element sends the identification information of the target service provider to the session management network element, and the session management network element sends the data network name information to the access and mobility management network element based on the identification information of the target service provider. Optionally, the access and mobility management network element may also send second indication information to the session management network element, wherein the second indication information is used to instruct the session management network element to send the data network name information to the access and mobility management network element.

[0214] Combination Figure 4For example, the user equipment sends a second request message to the access and mobility management network element, wherein the second request message includes SP ID1. Based on SP ID1 in the second request message, the access and mobility management network element determines that there is no DNN1 corresponding to SP ID1 in the access and mobility management network element, then obtains the DNN1 from the session management network element and sends the DNN1 to the user equipment.

[0215] In the second optional implementation, the user equipment can send the first call information as the first information to the session management network element.

[0216] In Architecture 1, each IMS network is equipped with a corresponding proxy call network element. The non-public network determines the target proxy call network element and the target IMS network to which the target proxy call network element belongs based on the first information.

[0217] For example, such as Figure 4 In the system architecture, the proxy call information corresponding to IMS network 1, IMS network 2, and IMS network 3 are proxy call information 1, proxy call information 2, and proxy call information 3, respectively. When the user equipment sends proxy call information 1 to the session management network element, the session management network element determines the target IMS network as IMS network 1 based on proxy call information 1 and selects a user plane function network element that can establish a connection with IMS network 1.

[0218] For example, the user equipment can determine the first call information in two ways: Method 1 and Method 2.

[0219] Method 1: The user equipment obtains the information from the access network equipment.

[0220] Access network equipment can broadcast a third set (also known as third information) to user equipment. The third set includes the identification information of the service providers to which each IMS network belongs in multiple non-public network connections and the corresponding proxy call information. The user equipment determines the corresponding proxy call information based on the identification information of its service provider. This proxy call information is the first call information.

[0221] Combination Figure 4 For example, the third set includes SP ID1 and proxy call information 1 corresponding to IMS network 1, SP ID2 and proxy call information 2 corresponding to IMS network 2, and SP ID3 and proxy call information 3 corresponding to IMS network 3. If the service provider to which the user equipment belongs corresponds to SP ID1, then the user equipment determines proxy call information 1 as the first piece of information from the third set.

[0222] It should be noted that the purpose of the user equipment (UE) obtaining the third set is to determine whether a target IMS network providing services to the UE exists among multiple IMS networks connected to a non-public network. Therefore, if the UE determines that the identifier information of its service provider exists in the third set, it is determined that a target IMS network exists among the multiple IMS networks, and the UE can establish a session connection through the non-public network to obtain IMS services provided by that target IMS network. If the UE determines that the target IMS network does not exist among the multiple IMS networks, it is determined that it cannot establish a session connection through the non-public network to obtain IMS services provided by that target IMS network.

[0223] Method 2: The user equipment obtains the domain name system server (DNS server).

[0224] User equipment can request first call information from the Domain Name System server.

[0225] For example, the user equipment is pre-configured with the domain name information of the IMS network provided by its service provider (i.e., the domain name information of the target IMS network). For example, the domain name information of the target IMS network could be ims.mnc99.mcc999.3gppnetwork.org; where mnc represents the mobile network code, which is the code for an operator's network within a country; and mcc represents the mobile country code, a three-digit code uniquely identifying a country. This domain name information indicates an IMS network provided by an operator with mobile network code 99 within a country where the mobile country code is 999.

[0226] The user equipment (UE) sends a third request message to the Domain Name System (DNS) server. This third request message includes the domain name information of the target IMS network and the identification information of a non-public network. The identification information of the non-public network can be a network identifier of the non-public network (e.g., a Public Land Mobile Network Identity (PLMN ID) + Network Identifier (NID)). Upon receiving the third request message, the DNS server determines the proxy call information (i.e., the first call information) corresponding to the target IMS network domain name based on the domain name information of the target IMS network and the identification information of the non-public network in the third request message. The proxy call network element indicated by the first call information is connected to the non-public network. The DNS server then sends a third response message containing the first call information to the UE.

[0227] In addition, if the Domain Name System (DNS) server determines that there is no proxy call information corresponding to the target IMS network domain name, the third response information fed back to the user equipment is used to indicate that the query failed, or to indicate that the target IMS network is not connected in a non-public network.

[0228] The Domain Name System (DNS) server can be deployed within the session management network element, or in other words, the session management network element has the functionality of a DNS server. In this approach, the user equipment (UE) obtains the first call information from the DNS server, which is equivalent to the UE obtaining the first call information from the session management network element. The UE can obtain the first call information from the session management network element through control plane messages or user plane messages.

[0229] In the second optional implementation, for example, a first correspondence is pre-obtained in the session management network element. This first correspondence includes the identification information and proxy call information (such as the address information of the proxy call network element) of the service providers corresponding to each of the multiple IMS networks connected to a non-public network. The user equipment sends first call information to the session management network element. The first call information may implicitly indicate the target service provider to which the user equipment belongs, or in other words, implicitly indicate the identification information of the target service provider to which the user equipment belongs.

[0230] Combination Figure 4 For example, Table 1 shows a first correspondence, which includes the identification information and proxy call information of the service providers corresponding to IMS networks 1 to 3 respectively. If the first call information is proxy call address information 1 (P-CSCF IP1), it can indicate that the target service provider to which the user equipment belongs is service provider 1, and the identification information of the target service provider is SP ID1.

[0231] Table 1

[0232] Service provider identification information Agent call information SP ID1 P-CSCF IP1 SP ID2 P-CSCF IP2 SP ID 3 P-CSCF IP3

[0233] In the third optional implementation, the user equipment sends the target service provider's identification information and the first call information together as the first information to the session management network element. The proxy call information corresponding to the target IMS network provided by the target service provider is this first call information. This specific implementation can refer to the first and second optional implementations described above, and will not be repeated here.

[0234] Step 602: The session management network element determines the first call information based on the first information.

[0235] Scenario 1: The first piece of information includes the identification information of the target service provider.

[0236] In Architecture 1, a corresponding proxy call network element is deployed in each IMS network. The session management network element determines the first call information based on the identification information of the target service provider included in the first information. The first call information instructs the target proxy call network element (i.e., the proxy call network element in the target IMS network), which is equivalent to the session management network element determining the target IMS network from multiple IMS networks connected to non-public networks.

[0237] In one optional implementation, the session management network element includes a first correspondence. Based on the target service provider's identification information, the session management network element determines the proxy call information corresponding to the target service provider's identification information from the first correspondence; this is the first call information. Referring to the example in Table 1 above, if the first information includes the target service provider's identification information as SP ID1, then the session management network element can determine that the first call information is P-CSCF IP1.

[0238] In Architecture 2, proxy call network elements without service provider attributes are deployed in non-public networks. The session management network element can determine the proxy call information (which can also be called the first call information) of the proxy call network elements without service provider attributes deployed in non-public networks based on the service provider's identification information.

[0239] Scenario 2: The first information includes the first call information.

[0240] The session management network element can determine the first call information from the first information.

[0241] Of course, the first information may also include the identification information of the target service provider and the first call information. The specific implementation can be referred to in Case 1 and Case 2 above, and will not be repeated here.

[0242] Step 603: The session management network element sends the first call information to the user equipment.

[0243] Correspondingly, the user equipment receives the first call information from the session management network element, and the user equipment can determine the destination address information of the IMS message based on the first call information.

[0244] For example, once a user equipment obtains the address information of a target proxy calling network element, it can send an IMS message to the target proxy calling network element to obtain IMS services provided by the target IMS network.

[0245] The above technical solution enables a single non-public network to connect to multiple IMS networks, providing IMS network services to user equipment from different service providers. Furthermore, the user equipment sends first information to the session management network element. This first information may include the target service provider's identification information and / or first call information. The session management network element can determine the target IMS network that the user equipment requests to connect to based on this first information, thereby establishing a session connection between the user equipment and the target IMS network. This eliminates the need for adding a local user server in the non-public network, helping to reduce deployment costs.

[0246] Furthermore, when the first piece of information is the data network name, the user equipment can use the existing session establishment process without adding any additional information cells or parameters. The non-public network can then know the IMS network that the user equipment is requesting to connect to and complete the session establishment.

[0247] Furthermore, it should be noted that in Architecture 2, a proxy call network element without a service provider attribute is deployed in a non-public network. Although the user equipment sends an IMS message to the target proxy call network element without a service provider attribute in the non-public network based on the first call information, the target proxy call network element is connected to IMS networks provided by multiple service providers. Before sending an IMS message to the target query call network element in the target IMS network, the target proxy call network element determines the target query call network element in the target IMS network.

[0248] In one optional implementation, the target agent calling network element obtains the target association relationship, which includes the user equipment's identification information and the corresponding query call information. The user equipment's identification information can be the user equipment's IP address or its identifier (ID). The corresponding query call information can be the address information of the query call network element in the IMS network corresponding to the service provider to which the user equipment belongs.

[0249] For example, Table 2 shows a target association relationship obtained by the target agent calling network element. Table 2 includes the identification information of the user equipment and the query call information corresponding to the user equipment. One or more user equipments may correspond to the same query call information.

[0250] Table 2

[0251] User equipment identification information Inquire about call information UE IP 1 I-CSCF IP1 UE IP 2 I-CSCF IP2 UE IP 3 I-CSCF IP3 UE IP 4 I-CSCF IP3 UE IP 5 I-CSCF IP3

[0252] In addition, the target association may also include the identification information of the service provider to which the user equipment belongs. For example, Table 3 shows another target association obtained by the target agent calling network element. Table 3 includes the identification information of the user equipment, the identification information of the service provider to which the user equipment belongs, and the query call information corresponding to the user equipment. One or more user equipments may correspond to the same query call information, and one or more user equipments may correspond to the identification information of the same service provider.

[0253] Table 3

[0254] User equipment identification information Service provider identification information Inquire about call information UE IP 1 SP ID1 I-CSCF IP1 UE IP 2 SP ID2 I-CSCF IP2 UE IP 3 SP ID3 I-CSCF IP3 UE IP 4 SP ID3 I-CSCF IP3 UE IP5 SP ID3 I-CSCF IP3

[0255] If the target agent calling network element receives an IMS message, it can determine the query call information (i.e., the second call information) corresponding to the user equipment identification information from the target association based on the user equipment identification information in the IMS message, and send an IMS message to the query call network element corresponding to the second call information.

[0256] For example, in Table 2, if the IMS message contains UE IP 1, the target agent calling network element determines that the second call information is I-CSCF IP1, and the target agent calling network element sends the IMS message to the query calling network element corresponding to I-CSCF IP1.

[0257] In this embodiment, the target proxy call network element can obtain the target association relationship from the session management network element or the policy control network element. Alternatively, the target association relationship can also be configured on the target proxy call network element.

[0258] For example, the session management network element or policy control network element determines the target association and sends the target association to the target agent calling network element. The following is a breakdown of different scenarios.

[0259] It should be noted that the target agent call network element, session management network element, or policy control network element can obtain a second mapping relationship. This second mapping relationship includes the identification information and query call information of the service providers corresponding to each IMS network in multiple IMS networks connected to non-public networks, combined with, for example... Figure 4 Table 4 shows a second correspondence, which includes the identification information and inquiry call information of the service providers corresponding to IMS network 1 to IMS network 3 respectively.

[0260] Table 4

[0261] Service provider identification information Inquire about call information SP ID1 I-CSCF IP1 SP ID2 I-CSCF IP2 SP ID 3 I-CSCF IP3

[0262] Case 1: The session management network element determines the target association relationship.

[0263] For example, the user equipment sends first information to the session management network element. The first information includes the identification information of the target service provider. The session management network element determines the association relationship between the identification information of the user equipment and the query call information based on the identification information of the target service provider and the identification information of the user equipment, combined with the second correspondence relationship, i.e., the target association relationship as shown in Table 2; or determines the association relationship between the identification information of the user equipment, the identification information of the service provider to which it belongs, and the query call information, i.e., the target association relationship as shown in Table 3.

[0264] The session management network element sends the target association relationship to the target agent calling network element, or the session management network element sends the target association relationship to the target agent calling network element through the policy control network element.

[0265] Case 2: The strategy control network element determines the target association relationship.

[0266] For example, the user equipment sends first information to the session management network element, which includes the identification information of the target service provider. The session management network element then sends second information to the policy control network element, which includes the identification information of the target service provider and the identification information of the user equipment. The policy control network element receives the second information and, in conjunction with the second correspondence, determines the association between the identification information of the user equipment and the query call information, i.e., the target association as shown in Table 2; or determines the association between the identification information of the user equipment, the identification information of the service provider to which it belongs, and the query call information, i.e., the target association as shown in Table 3.

[0267] The policy control network element sends the target association relationship to the target agent calling network element.

[0268] Scenario 3: The target agent calls the network element to determine the target association relationship.

[0269] For example, the user equipment sends first information to the session management network element, which includes the identification information of the target service provider. The session management network element then sends second information, which includes the identification information of the target service provider and the identification information of the user equipment, to the target proxy call network element, or sends the second information to the target proxy call network element through the policy control network element. The target proxy call network element receives the second information and, in conjunction with the second correspondence, determines the association between the identification information of the user equipment and the query call information, i.e., the target association as shown in Table 2; or determines the association between the identification information of the user equipment, the identification information of the service provider to which it belongs, and the query call information, i.e., the target association as shown in Table 3.

[0270] The above technical solution enables a single non-public network to connect multiple IMS networks, providing IMS network services to user equipment from different service providers. When a proxy call network element without service provider attributes is deployed in a non-public network, this proxy call network element can determine the query call network element based on the target association relationship, and then send IMS messages from the user equipment to that query call network element.

[0271] Based on the same inventive concept, such as Figure 7 This is a schematic diagram of the first process for establishing a session connection between a user equipment and a target IMS network, which is provided as an example in this application. This embodiment can be applied to the case in Architecture 1 where a corresponding proxy call network element is deployed in each IMS network.

[0272] The first information includes the identification information of the target service provider. Based on the identification information of the target service provider, the non-public network determines the first call information used to instruct the target agent to call the network element. The first call information is used to establish a session connection between the user equipment and the target IMS network.

[0273] Step 701: The user equipment sends a session establishment request message to the access and mobility management network element. For example, the user equipment sends a NAS message to the access and mobility management network element, which includes parameters such as a session identifier, the data network name requested by the user equipment, slice information, and the identification information of the target service provider.

[0274] Optionally, in step 702, the access and mobility management network element selects the session management network element.

[0275] Step 703: The access and mobility management network element sends a session context creation request message to the session management network element. For example, the access and mobility management network element sends a PDU session context creation request message to the session management network element. The PDU session context creation request message carries parameters such as the session identifier, the data network name requested by the user equipment, and also includes the identification information of the target service provider.

[0276] Step 704: The session management network element sends a session context creation response message to the access and mobility management network element. For example, the session management network element sends a PDU session creation session context response message to the access and mobility management network element.

[0277] Step 705: The session management network element selects a user plane function network element. For example, the session management network element selects a user plane function network element connected to the IMS network provided by the target service provider from multiple user plane function network elements based on the identification information of the target service provider.

[0278] Step 706: The session management network element establishes an N4 connection with the user plane function network element.

[0279] Step 707: The session management network element determines the first call information based on the first correspondence and the identification information of the target service provider.

[0280] Step 708: The session management network element sends the first call information to the access and mobility management network element. For example, the session management network element sends an N1N2 message (Namf_Communication_N1N2Messagetransfer) to the access and mobility management network element, wherein the N1N2 message includes the first call information.

[0281] Step 709: The access and mobility management network element sends the first call information to the user equipment.

[0282] For example, the access and mobility management network element sends a NAS message to the user equipment. This NAS message carries the aforementioned first call information.

[0283] Step 710: The user equipment requests to establish a connection with the target agent call network element based on the received first call information.

[0284] For example, the user equipment sends SIP signaling (also known as IMS signaling or IMS message) to the target proxy call network element based on the received first call information. This SIP signaling is used to request the establishment of a connection with the IMS network. The destination address of the SIP signaling is the address of the target proxy call network element indicated by the first call information.

[0285] Steps not described in detail in the embodiments of this application can be found in [reference needed]. Figure 3 or Figure 6 The relevant embodiments are illustrated.

[0286] Based on the same inventive concept, such as Figure 8 This application provides a schematic diagram of a second process for establishing a session connection between a user equipment and a target IMS network. This embodiment can be applied to the case in Architecture 1 where a corresponding proxy call network element is deployed in each IMS network.

[0287] The first information is data network name information, which includes the identification information of the target service provider. The non-public network determines the first call information to instruct the target agent to call the network element based on the identification information of the target service provider, thereby establishing a session connection between the user equipment and the target IMS network.

[0288] Step 801: The user equipment can obtain the data network name information based on the method in Example 1 or Example 2 below.

[0289] Example 1: The user equipment obtains the data network name information from the access and mobility management network element, which can be done by referring to steps 801-1 to 801-5 below.

[0290] Step 801-1: The user equipment sends a second request message to the access and mobility management network element, which includes the identification information of the target service provider. For example, the second request message can be carried in a NAS message, which can specifically be a registration request message sent by the user equipment to the access and mobility management network element during the registration process.

[0291] Step 801-2a: If the access and mobility management network element contains data network name information corresponding to the identification information of the target service provider, then proceed to step 801-5.

[0292] Step 801-2b: If there is no data network name information corresponding to the identification information of the target service provider in the access and mobility management network element, then proceed to steps 801-3 to 801-5.

[0293] Step 801-3: The access and mobility management network element sends the identification information of the target service provider to the session management network element.

[0294] Step 801-4: The session management network element sends data network name information to the access and mobility management network element. The information between the access and mobility management network element and the session management network element can be carried in an Nsmf message.

[0295] Step 801-5: The access and mobility management network element sends data network name information to the user equipment.

[0296] Example 2: The user equipment obtains the data network name information from the access network equipment, which can be done by referring to steps 801-6 and 801-7 below.

[0297] Step 801-6: The access network device broadcasts a second set, which includes data network name information corresponding to each IMS network among multiple IMS networks connected to a non-public network.

[0298] Step 801-7: The user equipment determines the data network name information corresponding to its service provider from the second set.

[0299] Step 802: The user equipment sends a session establishment request message to the access and mobility management network element. For example, the user equipment sends a NAS message to the access and mobility management network element, which includes parameters such as session identifier, data network name information, and slice information. The data network name information includes the identifier of the target service provider.

[0300] Optionally, in step 803, the access and mobility management network element selects the session management network element.

[0301] Step 804: The access and mobility management network element sends a session context creation request message to the session management network element. For example, the access and mobility management network element sends a PDU session context creation request message to the session management network element, which carries parameters such as session identifier, data network name information, and slice information. The data network name information includes the identifier of the target service provider.

[0302] Step 805: The session management network element sends a session context creation response message to the access and mobility management network element. For example, the session management network element sends a PDU session creation session context response message to the access and mobility management network element.

[0303] Step 806: The session management network element selects a user plane function network element. For example, the session management network element selects a user plane function network element from multiple user plane function network elements that connects to the target IMS network provided by the target service provider, based on the identifier information of the target service provider in the data network name information.

[0304] Step 807: The session management network element establishes an N4 connection with the user plane function network element.

[0305] Step 808: The session management network element determines the first call information based on the first correspondence and the identification information of the target service provider.

[0306] Step 809: The session management network element sends the first call information to the access and mobility management network element. For example, the session management network element sends an N1N2 message (Namf_Communication_N1N2Messagetransfer) to the access and mobility management network element, wherein the N1N2 message includes the first call information.

[0307] Step 810: The access and mobility management network element sends the first call information to the user equipment.

[0308] Step 811: The user equipment requests to establish a connection with the target agent call network element based on the received first call information.

[0309] For example, the user equipment sends SIP signaling (also known as IMS signaling or IMS message) to the target proxy call network element based on the received first call information. This SIP signaling is used to request the establishment of a connection with the IMS network. The destination address of the SIP signaling is the address of the target proxy call network element indicated by the first call information.

[0310] Steps not described in detail in the embodiments of this application can be found in [reference needed]. Figure 3 or Figure 6 The relevant embodiments are illustrated.

[0311] Based on the same inventive concept, such as Figure 9 This application provides a schematic diagram of a third method for establishing a session connection between a user equipment and a target IMS network. This embodiment can be applied to the case in Architecture 1 where a corresponding proxy call network element is deployed in each IMS network.

[0312] The first information includes first call information, which is used to instruct the target agent to call the network element. The non-public network establishes a session connection between the user equipment and the target IMS network based on the first call information.

[0313] Step 901: The user equipment may obtain the first call information based on the method in Example 1 or Example 2 below.

[0314] Example 1: The user equipment obtains the first call information from the Domain Name System server, which can be done by referring to steps 901-1 and 901-2 below.

[0315] Step 901-1: The user equipment sends a third request to the Domain Name System server, which includes the domain name information of the target IMS network and the identification information of the non-public network.

[0316] Step 901-2: The Domain Name System (DNS) server determines the proxy call information (i.e., the first call information) corresponding to the domain name of the target IMS network based on the domain name information of the target IMS network and the identification information of the non-public network. The DNS server then sends the first call information to the user equipment.

[0317] Example 2: The user equipment obtains the first call information from the access network equipment, which can be done by referring to steps 901-3 and 901-4 below.

[0318] Step 901-3: The access network device broadcasts a third set, which includes the identification information of the service providers to which each IMS network belongs and the corresponding proxy call information in multiple IMS networks connected to a non-public network.

[0319] Step 901-4: The user equipment determines the first call information from the third set.

[0320] Step 902: The user equipment sends a session establishment request message to the access and mobility management network element. For example, the user equipment sends a NAS message to the access and mobility management network element, which includes parameters such as a session identifier, the data network name requested by the user equipment, and slice information. It also includes first call information, which may indicate the identification information of the target service provider.

[0321] Optionally, in step 903, the access and mobility management network element selects the session management network element.

[0322] Step 904: The access and mobility management network element sends a session context creation request message to the session management network element. For example, the access and mobility management network element sends a PDU session context creation request message to the session management network element, which includes parameters such as session identifier, data network name requested by the user equipment, slice information, and first call information.

[0323] Step 905: The session management network element sends a session context creation response message to the access and mobility management network element. For example, the session management network element sends a PDU session creation session context response message to the access and mobility management network element.

[0324] Step 906: The session management network element selects a user plane function network element. For example, the session management network element selects a user plane function network element connected to the IMS network provided by the target service provider from multiple user plane function network elements based on the identification information of the target service provider. Optionally, the session management network element can determine the identification information of the target service provider based on the first call information.

[0325] Step 907: The session management network element establishes an N4 connection with the user plane function network element.

[0326] Step 908: The session management network element sends the first call information to the access and mobility management network element. For example, the session management network element sends an N1N2 message (Namf_Communication_N1N2Messagetransfer) to the access and mobility management network element. The N1N2 message includes the first call information.

[0327] Step 909: The access and mobility management network element sends the first call information to the user equipment.

[0328] Step 910: The user equipment requests to establish a connection with the target agent call network element based on the received first call information.

[0329] For example, the user equipment sends SIP signaling (also known as IMS signaling or IMS message) to the target proxy call network element based on the received first call information. This SIP signaling is used to request the establishment of a connection with the IMS network. The destination address of the SIP signaling is the address of the target proxy call network element indicated by the first call information.

[0330] Steps not described in detail in the embodiments of this application can be found in [reference needed]. Figure 3 or Figure 6 The relevant embodiments are illustrated.

[0331] Based on the same inventive concept, such as Figure 10 This application provides a schematic diagram of a fourth process for establishing a session connection between a user equipment and a target IMS network. This embodiment can be applied to the case of deploying a proxy call network element without service provider attributes in a non-public network in Architecture 2.

[0332] The first information includes the identification information of the target service provider. The non-public network determines the second call information based on the identification information of the target service provider, and then sends an IMS message from the user equipment to the target IMS network.

[0333] Step 1001: The user equipment sends a session establishment request message to the access and mobility management network element. For example, the user equipment sends a NAS message to the access and mobility management network element, which includes parameters such as a session identifier, the data network name requested by the user equipment, and identification information of the target service provider.

[0334] Optionally, in step 1002, the access and mobility management network element selects the session management network element.

[0335] Step 1003: The access and mobility management network element sends a session context creation request message to the session management network element. For example, the access and mobility management network element sends a PDU session context creation request message to the session management network element, which includes a session identifier, the data network name requested by the user equipment, slice information, and the identifier information of the target service provider.

[0336] Step 1004: The session management network element sends a session context creation response message to the access and mobility management network element. For example, the session management network element sends a PDU session creation session context response message to the access and mobility management network element.

[0337] Step 1005: The session management network element and the policy control network element establish a session policy association.

[0338] Step 1006: The session management network element selects a user plane function network element. For example, the session management network element selects a user plane function network element connected to the IMS network provided by the target service provider from multiple user plane function network elements based on the identification information of the target service provider.

[0339] Step 1007: The session management network element establishes an N4 connection with the user plane function network element.

[0340] Step 1008: The session management network element and the policy control network element perform session policy association modification.

[0341] In step 1008, the session management network element sends the identification information of the user equipment and the identification information of the target service provider to the policy control network element. The policy control network element determines the target association relationship, which includes the identification information of the user equipment and the second call information, or includes the identification information of the user equipment, the identification information of the target service provider and the second call information.

[0342] Step 1009: The policy control network element sends the target association relationship to the target agent calling network element.

[0343] Steps 1008 and 1009 can be referenced. Figure 6 The description of situation 2 in the explanation.

[0344] Step 1010: The session management network element determines the first call information based on the identification information of the target service provider. The first call information is used to instruct the target agent to call the network element.

[0345] Step 1011: The session management network element sends the first call information to the access and mobility management network element. For example, the session management network element sends an N1N2 message (Namf_Communication_N1N2Messagetransfer) to the access and mobility management network element. The N1N2 message includes the first call information.

[0346] Step 1012: The access and mobility management network element sends the first call information to the user equipment.

[0347] Step 1013: The user equipment requests to establish a connection with the target agent call network element based on the received first call information.

[0348] For example, the user equipment (UE) sends SIP signaling (also known as IMS signaling or IMS message) to the proxy call network element. This SIP signaling is used to request the establishment of a connection between the UE and the IMS network. The destination address of the SIP signaling is the address of the target proxy call network element indicated by the first call information, and the source address of the SIP signaling is the IP address of the UE. The proxy call network element determines the query call information corresponding to the SIP signaling based on the obtained target association relationship and sends the SIP signaling to the query call network element corresponding to the query call information.

[0349] It should be noted that steps 1008 and 1009 above use the policy control network element determining the target association relationship as an example. In this embodiment, the session management network element can also determine the target association relationship and send it to the policy control network element, which then sends the target association relationship to the target agent call network element. For details, please refer to [link / reference]. Figure 6The description in Case 1 in the explanation is as follows. Alternatively, in the embodiments of this application, the target association relationship can also be determined by the target proxy calling network element. For example, the session management network element can send the user equipment identification information and the target service provider identification information to the policy control network element, and then the policy control network element sends the user equipment identification information and the target service provider identification information to the target proxy calling network element. The target proxy calling network element determines the target association relationship. For details, please refer to [link / reference]. Figure 6 The description of situation 3 in the explanation.

[0350] Furthermore, it should be noted that the embodiments of the present invention do not limit the order in which steps 1008 and 1009 are executed with subsequent steps 1010 to 1013.

[0351] Steps not described in detail in the embodiments of this application can be found in [reference needed]. Figure 3 or Figure 6 The relevant embodiments are illustrated.

[0352] Furthermore, among the one or more IMS networks connected to the non-public network accessed by the user equipment in this application, there may not be an IMS network requested (or supported) by the user equipment. In this case, if the core network equipment selects a target IMS network from the one or more IMS networks when the user equipment requests to establish a session for obtaining IMS services, and the user equipment does not support connecting to the target IMS network (or can be understood as the user equipment not being a user of the target IMS network), then the user equipment cannot obtain IMS services. Thus, the user equipment not only cannot obtain IMS services, but also occupies network resources.

[0353] This application also provides a communication method for enabling user equipment to connect to a service provider's IMS network via a non-public network. That is, when one or more IMS networks include an IMS network to which the user equipment requests a connection, the method enables the establishment of a connection between the user equipment and that IMS network. Or, when one or more IMS networks do not include an IMS network to which the user equipment requests a connection, the method avoids establishing a connection between the user equipment and an IMS network that the user equipment does not support, thereby helping to reduce resource waste and signaling overhead.

[0354] For ease of description, the IMS network to which the user equipment requests connection can be referred to as the first IMS network. The IMS network selected by the core network equipment for the user equipment can be referred to as the second IMS network. The IMS network connected to the non-public network accessed by the user equipment can be referred to as the third IMS network. The core network equipment can select the second IMS network for the user equipment from one or more third IMS networks. Furthermore, the establishment of a connection between the user equipment and the first IMS network can be understood as the user equipment establishing a session connection with the data network to which the first IMS network belongs, or the user equipment establishing an IP connection with the proxy call element of the first IMS network, or the user equipment establishing an IP connection with the first IMS network.

[0355] It should also be noted beforehand that core network equipment can pre-acquire network information of one or more third-party IMS networks. In one possible implementation, the core network equipment can be an access and mobility management (AMI) network element, a session management (SMA) network element, or a unified data management (UDM) network element. When the core network equipment is an AMI network element, it can acquire network information of one or more third-party IMS networks from the session management (SMA) network element or the UDM network element, or the AMI network element can pre-configure the network information of the one or more third-party IMS networks. When the core network equipment is a SMA network element, it can acquire network information of one or more third-party IMS networks from the UDM network element, or the SMA network element can pre-configure the network information of the one or more third-party IMS networks.

[0356] This application can be described separately based on the user device registration process and the session establishment process.

[0357] Scenario 1: The user device registration process.

[0358] Figure 11 A flowchart illustrating a first method for establishing a connection between a user equipment and an IMS network is shown. This method may include the following steps:

[0359] Step 1101: The user equipment sends a registration request message to the access network device. This registration request message can be a NAS message.

[0360] Step 1102: The access network device selects the access and mobility management network element.

[0361] Step 1103: The access network device sends a registration request message to the access and mobility management network element.

[0362] The registration request message may include IMS capability information, which indicates that the user equipment supports obtaining IMS services, or indicates that the user equipment supports establishing a connection with the IMS network, or indicates that the user equipment supports obtaining network information of the IMS network, or indicates that the user equipment supports the network information of the connected IMS network.

[0363] In one example, IMS capability information can be indication information. For instance, this indication information can indicate that the user equipment supports obtaining IMS services, or it can indicate that the user equipment does not support obtaining IMS services. For instance, this indication information can be a single bit, multiple bits, or a string. When the indication information is a single bit, a value of 1 indicates that the user equipment supports obtaining IMS services, and a value of 0 indicates that the user equipment does not support obtaining IMS services. Alternatively, when the indication information is a single bit, a value of 0 indicates that the user equipment supports obtaining IMS services, and a value of 1 indicates that the user equipment does not support obtaining IMS services. When the indication information is multiple bits, one type of multiple bits can indicate that the user equipment does not support obtaining IMS services, and another type of multiple bits can indicate that the user equipment supports obtaining IMS services. When the indication information is a string, one type of string can indicate that the user equipment does not support obtaining IMS services, and another type of string can indicate that the user equipment supports obtaining IMS services.

[0364] In another example, the IMS capability information may include network information of the first IMS network. Further, the IMS capability information can be network information of the first IMS network. The network information of the first IMS network may include one or more of the following: the service provider identifier, network identifier, network domain name, data network name, and address information of the proxy call network element. It can be understood that the user equipment implicitly indicates to the mobility management network element that the user equipment supports obtaining IMS services, and the user equipment requests or supports establishing a connection with the first IMS network.

[0365] It should be noted that user equipment can also send IMS capability information to the access and mobility management network element through a separate message, or user equipment can also carry the IMS capability information in other messages in the registration process and send it to the access and mobility management network element.

[0366] Step 1104: Select the authentication server function network element for the access and mobility management network element.

[0367] Step 1105, User Equipment Authentication Process.

[0368] The authentication process can be found in the descriptions of the user equipment authentication process in sections 6.1.2 and 6.1.3 of TS 33.501.

[0369] Step 1106: The access and mobility management network element sends a registration accept message to the user equipment.

[0370] In one possible implementation, the access and mobility management network element can send network information of one or more third-party IMS networks to the user equipment based on IMS capability information. The network information of the third-party IMS network may include one or more of the following: the service provider identifier, network identifier, network domain name, data network name, and address information of the proxy call network element.

[0371] In another possible implementation, the access and mobility management network element can also select one of the third IMS networks (i.e., the second IMS network) for the user equipment from one or more third IMS networks based on the IMS capability information, and send the network information of the second IMS network to the user equipment. The network information of the second IMS network may include one or more of the following: the service provider identifier, network identifier, network domain name, data network name, and address information of the proxy call network element.

[0372] Optionally, after receiving a registration request message, the access and mobility management network element (AMI) can respond to the IMS capability information in the registration request message by including network information of one or more third-party IMS networks in a registration acceptance message and sending the registration acceptance message to the user equipment. Of course, if the registration request message does not include IMS capability information, the AMI can also send a registration acceptance message to the user equipment carrying network information of one or more third-party IMS networks. Compared to the latter option, the former option allows the AMI to send network information of one or more third-party IMS networks to the user equipment based on the indication information sent by the user equipment, which helps reduce signaling overhead.

[0373] Step 1107: The user equipment initiates a session establishment procedure based on network information from one or more third-party IMS networks. This session establishment procedure is used by the user equipment to obtain IMS services.

[0374] When a first IMS network is included in one or more third IMS networks, the user equipment may initiate a session establishment procedure; when a first IMS network is not included in one or more third IMS networks, the user equipment may not initiate the session establishment procedure to the session management network element.

[0375] In one example, when the access and mobility management network element sends network information of one or more third-party IMS networks connected to a non-public network accessed by the user equipment, if the user equipment obtains the network information of the first IMS network from the network information of one or more third-party IMS networks, it can initiate a session establishment procedure. If the user equipment does not obtain the network information of the first IMS network from the network information of one or more third-party IMS networks, it does not need to initiate a session establishment procedure to obtain IMS services. In another example, when the access and mobility management network element selects the network information of one third-party IMS network (i.e., the network information of the second IMS network) from the network information of one or more third-party IMS networks for the user equipment, the user equipment determines whether the second IMS network is the same as the first IMS network. If they are the same, it can initiate a session establishment procedure; if they are different, it does not need to initiate a session establishment procedure to obtain IMS services.

[0376] In one possible implementation, the user equipment initiating a session establishment process can be understood as the user equipment sending a session establishment request to the access and mobility management network element; the access and mobility management network element then sends the session establishment request to the session management network element. In another possible implementation, the user equipment initiating a session establishment process can be understood as the user equipment sending a session establishment request to the session management network element.

[0377] Furthermore, in step 1106 above, the registration receiving message may not carry network information of one or more third-party IMS networks. Instead, the access and mobility management network element sends the network information of one or more third-party IMS networks as a separate message to the user equipment. Alternatively, in another implementation, the access network device can obtain the network information of one or more third-party IMS networks. For example, the access network device obtains the network information of one or more third-party IMS networks from the access and mobility management network element, and then broadcasts the network information of one or more third-party IMS networks. The user equipment can then determine whether to initiate the session establishment process based on the network information of one or more third-party IMS networks. This broadcast message can be sent periodically, before, during, or after the user equipment's registration process.

[0378] During the registration process, the user equipment (UE) obtains network information of one or more IMS networks connected to the non-public network it accesses from the core network equipment. Based on this network information, the UE determines whether the one or more IMS networks include a first IMS network. This is equivalent to the UE determining whether an IMS network capable of providing IMS services exists among the one or more IMS networks connected to its non-public network. If the UE determines that an IMS network capable of providing IMS services exists among the one or more IMS networks connected to its non-public network, it can initiate a session establishment process to obtain IMS services.

[0379] In this approach, if a user equipment (UE) finds an IMS network among one or more non-public networks connected to it that can provide IMS services, it initiates a request to obtain IMS services. This reduces the likelihood of a UE blindly initiating a request to obtain IMS services due to uncertainty about the existence of the requested IMS network, which could lead to a rejection message. Since both initiating the request and receiving the rejection message consume signaling and network resources, this approach further reduces signaling consumption and network resource consumption.

[0380] Figure 12 The flowchart illustrates a second method for establishing a connection between a user equipment and the IMS network. The core network equipment can be an access and mobility management network element. This method may include the following steps:

[0381] Step 1201: The user equipment sends a registration request message to the access network equipment.

[0382] The registration request message can be a NAS message.

[0383] Step 1202: The access network device selects the access and mobility management network element.

[0384] Step 1203: The access network device sends a registration request message to the access and mobility management network element.

[0385] The registration request message may include network information of the first IMS network requested by the user equipment. Optionally, the network information of the first IMS network may include one or more of the following: the service provider identifier, network identifier, network domain name, data network name, and address information of the proxy call element of the first IMS network.

[0386] It should be noted that the user equipment can also send the network information of the first IMS network to the access and mobility management network element through a separate message, or the user equipment can also carry the network information of the first IMS network in other messages in the registration process and send them to the access and mobility management network element.

[0387] Step 1204: Select the authentication server function network element for the access and mobility management network element.

[0388] Step 1205, User Equipment Authentication Process.

[0389] The authentication process can be found in the descriptions in sections 6.1.2 and 6.1.3 of TS 33.501.

[0390] Step 1206: The access and mobility management network element sends a registration acceptance message to the user equipment.

[0391] Step 1207: The access and mobility management network element sends the fourth information to the user equipment.

[0392] In one possible approach, the access and mobility management network element (IMM) obtains network information from one or more third-party IMS networks. When the IIM receives network information from a first-party IMS network from a registration request message, the IIM can determine whether the first-party IMS network is included among the one or more third-party IMS networks. Then, the IIM sends fourth information to the user equipment (UE), which indicates whether the first-party IMS network is included among the one or more third-party IMS networks, or indicates whether establishing a connection between the UE and the first-party IMS network is supported.

[0393] In one possible approach, the fourth information may include network information of one or more third IMS networks. For example, the fourth information may include one or more of the following: service provider identifier, network identifier, network domain name, address information of the proxy call element, and data network name information of one or more third IMS networks. The user equipment can determine whether the first IMS network is included among the one or more third IMS networks based on the network information of these third IMS networks.

[0394] In another possible approach, the fourth information may include network information of the first IMS network. For example, the fourth information may include one or more of the following: the service provider identifier, network identifier, network domain name, address information of the proxy call element, and data network name information of the first IMS network. The user equipment can determine that the first IMS network is included in one or more third IMS networks based on the network information of the first IMS network.

[0395] In addition, the fourth information can be a separate message, or it can be included in the registration acceptance message (in which case steps 1206 and 1207 are one step, and the registration acceptance message includes the fourth information).

[0396] Step 1208: The user equipment initiates a session establishment process based on the fourth piece of information. This session establishment process is used by the user equipment to obtain IMS services.

[0397] When the fourth information indicates that the first IMS network is included among one or more third IMS networks, the user equipment (UE) may initiate a session establishment procedure. Specifically, the UE may send a session establishment request message to the access and mobility management (AML) network element; the AML network element may send a session establishment request message to the session management (SEM) network element; or the UE may send a session establishment request message to the SEM network element. The SEM network element establishes a connection between the UE and the first IMS network based on the session establishment request message. When the fourth information indicates that the first IMS network is not included among one or more third IMS networks, the UE may not initiate the session establishment procedure.

[0398] During the registration process, the user equipment (UE) sends the network information of the first IMS requested by the UE to the core network equipment. Based on this information, the core network equipment can determine whether one or more IMS networks connected to the non-public network accessed by the UE include the first IMS network. This is equivalent to the core network equipment determining whether an IMS network capable of providing IMS services exists among the one or more IMS networks connected to the non-public network accessed by the UE. If such an IMS network exists, the core network equipment can instruct the UE to initiate a session establishment process after successful registration to obtain IMS services. In this method, if an IMS network capable of providing IMS services exists among the one or more IMS networks connected to the non-public network accessed by the UE (i.e., the fourth information indicates support for establishing a connection between the UE and the first IMS network), the UE can request IMS services.

[0399] By using the above method, the user equipment only initiates a request to obtain IMS services after confirming the existence of an IMS network capable of providing IMS services to itself. This reduces the process of user equipment blindly initiating a request to obtain IMS services due to uncertainty about the existence of such an IMS network, and subsequently receiving a rejection message. Since both initiating a request to obtain IMS services and receiving a rejection message during this process incur signaling consumption and network resource occupation, this method can further reduce signaling consumption and network resource occupation.

[0400] Scenario 2: Session request process of user equipment.

[0401] Figure 13 The flowchart illustrates a third method for establishing a connection between a user equipment and the IMS network. The core network equipment can be a session management network element, and the method may include the following steps:

[0402] Step 1301: The user equipment sends a session establishment request message to the access and mobility management network element. The session establishment request message may include a session identifier, data network name, slice information, etc.

[0403] The session establishment request message may also include IMS capability information, which indicates that the user equipment supports obtaining IMS services, or indicates that the user equipment supports establishing a connection with the IMS network, or indicates that the user equipment supports network information of the connected IMS network, or indicates that the user equipment supports obtaining network information of the IMS network.

[0404] In one example, IMS capability information can be indication information. For instance, this indication information can indicate that the user equipment supports obtaining IMS services, or it can indicate that the user equipment does not support obtaining IMS services. For instance, this indication information can be a single bit, multiple bits, or a string. When the indication information is a single bit, a value of 1 indicates that the user equipment supports obtaining IMS services, and a value of 0 indicates that the user equipment does not support obtaining IMS services. Alternatively, when the indication information is a single bit, a value of 0 indicates that the user equipment supports obtaining IMS services, and a value of 1 indicates that the user equipment does not support obtaining IMS services. When the indication information is multiple bits, one type of multiple bits can indicate that the user equipment does not support obtaining IMS services, and another type of multiple bits can indicate that the user equipment supports obtaining IMS services. When the indication information is a string, one type of string can indicate that the user equipment does not support obtaining IMS services, and another type of string can indicate that the user equipment supports obtaining IMS services.

[0405] In another example, the IMS capability information may include network information of the first IMS network. Further, the IMS capability information may be network information of the first IMS network. The network information of the first IMS network may include one or more of the following: the service provider identifier, network identifier, network domain name, data network name, and address information of the proxy call network element. It can be understood that the user equipment implicitly indicates to the access and mobility management network element that the user equipment supports obtaining IMS services, and that the user equipment requests or supports establishing a connection with the first IMS network.

[0406] Step 1302: Select the session management network element for access and mobility management.

[0407] Step 1303: The access and mobility management network element sends a session context creation request message to the session management network element. This message may contain IMS capability information. Additionally, the session context creation request message may also contain session identifiers, data network names, and slice information.

[0408] Step 1304: The session management network element selects a second IMS network for the user equipment from one or more third IMS networks based on the network information of one or more third IMS networks. Optionally, the session management network element may select a second IMS network in response to the IMS capability information in the Create Session Context Request message.

[0409] Step 1305: The session management network element sends a session context creation response message to the access and mobility management network element.

[0410] Step 1306: The session management network element establishes an N4 connection with the user plane function network element.

[0411] Step 1307: The session management network element sends an N1N2 message to the access and mobility management network element.

[0412] In one possible implementation, the N1N2 message may include network information of the second IMS network. This network information may include one or more of the following: the service provider identifier, network identifier, network domain name, data network name, and address information of the proxy call element.

[0413] In one possible implementation, the N1N2 message may include an N1 session container (N1 SM container) and N2 session information (N2 SM information), wherein the N1 SM container information is forwarded by the access and mobility management network element to the user equipment, and the N2 SM information information is forwarded by the access and mobility management network element to the access network equipment.

[0414] The session management network element in the N1 SM container can include session establishment and acceptance information, as well as network information of the second IMS network.

[0415] Step 1308: The access and mobility management network element sends an N2 message to the access network device. The N2 message includes information sent by the session management network element to the user equipment, namely, network information of the second IMS network. For example, the N2 message includes N2 SM information and N1 SM container information, wherein the N1 SM container information is sent by the access and mobility management network element to the user equipment via a NAS message.

[0416] Step 1309: The access network equipment establishes air interface resources with the user equipment.

[0417] Step 1310: The user equipment determines whether the second IMS network is the same as the first IMS network. That is, the user equipment determines whether the IMS network selected by the session management network element is the IMS network requested by the user equipment. If yes, proceed to step 1311; otherwise, proceed to step 1312.

[0418] Step 1311: The user equipment obtains the address information of the proxy call element of the first IMS network. Based on the address information of the proxy call element of the first IMS network, the user equipment establishes a connection with the corresponding proxy call element of the first IMS network. After establishing a connection with the corresponding proxy call element of the first IMS network, the user equipment can obtain IMS services through this connection.

[0419] In one example, the network information of the second IMS network may include the address information of the proxy call network element of the second IMS network. The user equipment receives the network information of the second IMS network, determines that the second IMS network is the same as the first IMS network, obtains the address information of the proxy call network element of the second IMS network (i.e., the first IMS network), and establishes a connection with the corresponding proxy call network element of the first IMS network based on the address information of the proxy call network element of the first IMS network.

[0420] In another example, the network information of the second IMS network may not include the address information of the proxy call network element of the second IMS network. The session management network element sends the network information of the second IMS network and the address information of the proxy call network element of the second IMS network to the access and mobility management network element. Then, the access and mobility management network element sends the network information of the second IMS network and the address information of the proxy call network element of the second IMS network to the user equipment. The user equipment determines that the second IMS network is the same as the first IMS network based on the network information of the second IMS network, and establishes a connection with the proxy call network element corresponding to the first IMS network based on the address information of the proxy call network element of the second IMS network (i.e., the first IMS network).

[0421] In another example, the network information of the second IMS network may not include the address information of the proxy call network element of the second IMS network. The session management network element sends the network information of the second IMS network to the access and mobility management network element. Then, the access and mobility management network element sends the network information of the second IMS network to the user equipment. The user equipment determines that the second IMS network is the same as the first IMS network based on the network information of the second IMS network, obtains the address information of the proxy call network element corresponding to the first IMS network from the domain name system server, and then establishes a connection with the proxy call network element based on the address information, thereby obtaining the IMS service of the first IMS network.

[0422] Optionally, the access and mobility management network element may include the network information of the second IMS network (or the network information of the second IMS network and the address information of the proxy call network element of the second IMS network) in the NAS message sent to the user equipment. For example, this NAS message may be forwarded by the access network device to the user equipment before, during, or after the establishment of air interface resources between the user equipment and the access network device.

[0423] Step 1312: The user equipment sends a session release request message to the access and mobility management network element to release the session, or sends a session modification request message to the access and mobility management network element to modify the session, which helps to save network resources.

[0424] In the above technical solution, the session management network element can select a second IMS network from one or more third IMS networks for the user equipment (UE), and send the network information of the second IMS network to the UE. The UE can then determine whether the second IMS network is a first IMS network supported by the UE based on this network information. If the second IMS network is the same as the first IMS network, the UE can request to establish a connection with the proxy call network element corresponding to the first IMS network. In this approach, when the second IMS network selected by the session management network element is the same as the first IMS network supported by the UE, the UE's request to establish a connection with the proxy call network element corresponding to the first IMS network helps reduce signaling overhead and network resource consumption.

[0425] It should be added that, in Figure 13In related implementations, the session management network element can also respond to IMS capability information by feeding back network information of one or more third-party IMS networks to the user equipment. In one possible implementation, the session management network element sends this network information to the user equipment through the access and mobility management network element. Correspondingly, the user equipment receives the network information from one or more third-party IMS networks and, based on this information, determines whether an IMS network capable of providing IMS services exists among the one or more IMS networks connected to its non-public network. If such an IMS network exists, the user equipment requests to establish a connection with the proxy call network element corresponding to the first IMS network. In this approach, when an IMS network capable of providing IMS services exists among the one or more IMS networks connected to its non-public network, the user equipment requests to establish a connection with the proxy call network element corresponding to that IMS network, which helps reduce signaling overhead and network resource consumption.

[0426] Figure 14 The flowchart illustrates a fourth method for establishing a connection between a user equipment and the IMS network. The core network equipment can be a session management network element, and the method may include the following steps:

[0427] Step 1401: The user equipment sends a session establishment request message to the access and mobility management network element.

[0428] The session establishment request message may include network information of the first IMS network to which the user equipment requests connection. This network information includes one or more of the following: the service provider identifier, network identifier, network domain name, data network name, and address information of the proxy call element. Optionally, the session establishment request message may also include a session identifier, slice information, etc.

[0429] Step 1402: Select the session management network element for access and mobility management.

[0430] Step 1403: The access and mobility management network element sends a session context creation request message to the session management network element. The session context creation request message may also carry network information of the first IMS network. Optionally, the session context creation request message may carry session identifiers, slice information, etc.

[0431] It is understood that the user equipment sends network information of the first IMS network to the access and mobility management network element, or the user equipment (via the access and mobility management network element) sends network information of the first IMS network to the session management network element.

[0432] Step 1404: The session management network element determines whether the first IMS network is included in one or more third IMS networks based on the network information of one or more third IMS networks.

[0433] If one or more third IMS networks include the first IMS network, then step 1405 can be executed; if one or more third IMS networks do not include the first IMS network, then step 1411 can be executed.

[0434] Step 1405: The session management network element sends a session context creation response message to the access and mobility management network element.

[0435] Step 1406: The session management network element establishes an N4 connection with the user plane function network element.

[0436] Step 1407: The session management network element sends the fourth information to the access and mobility management network element.

[0437] For example, the session management network element sends an N1N2 message to the access and mobility management network element, and the N1N2 message may include fourth information.

[0438] In one possible implementation, the fourth information may include session establishment acceptance information and / or network information of the first IMS network.

[0439] In this application, the fourth information can be used to indicate that one or more third IMS networks include the first IMS network, or to indicate support for establishing a connection between the user equipment and the first IMS network. When one or more third IMS networks include the first IMS network, the session management network element can send the fourth information to the user equipment.

[0440] For example, the fourth piece of information may be indication information, which can be used to indicate support for establishing a connection between the user equipment and the first IMS network. For example, the indication information may be a single bit, multiple bits, or a string, wherein when the indication information is a single bit, a value of 1 indicates support for establishing a connection between the user equipment and the first IMS network. Alternatively, when the indication information is a single bit, a value of 0 indicates support for establishing a connection between the user equipment and the first IMS network. When the indication information is multiple bits, one type of multiple bits may indicate support for establishing a connection between the user equipment and the first IMS network. When the indication information is a string, one type of string may indicate support for establishing a connection between the user equipment and the first IMS network.

[0441] In one possible implementation, the N1N2 message may include an N1 SM container, where the N1 SM container information is forwarded by the session management network element to the user equipment through the access and mobility management network element.

[0442] In one possible implementation, the session management network element in the N1 SM container may include session establishment acceptance information, which may include message type information and / or parameter information of the session establishment acceptance message. The N1 SM container may also include network information of the first IMS network, specifically the address information of the proxy call network element of the first IMS network. In other words, in one possible implementation, the session management network element in the N1 SM container may include fourth information.

[0443] Step 1408: The access and mobility management network element sends an N2 message to the access network device.

[0444] The N2 message includes information from the NAS message sent by the access and mobility management network element to the user equipment.

[0445] The NAS message may include information sent by the session management network element to the user equipment; that is, the NAS message may include information about the N1 SM container. In other words, in one possible implementation, the NAS message may include a fourth piece of information.

[0446] Step 1409: The access network equipment establishes air interface resources with the user equipment.

[0447] This air interface resource is used to transmit user plane data of the user equipment. In one possible implementation, the user equipment can establish a connection with the call agent element of the first IMS network through this air interface resource.

[0448] For example, the NAS message may be forwarded by the access network device to the user equipment before, during, or after the user equipment establishes air interface resources with the access network device.

[0449] Step 1410: The user equipment establishes a connection with the proxy call element corresponding to the first IMS network based on the address information of the proxy call element of the first IMS network.

[0450] Step 1411: The session management network element sends the fourth information to the access and mobility management network element.

[0451] For example, the session management network element sends an N1N2 message to the access and mobility management network element, and the N1N2 message may include fourth information.

[0452] In this step, the fourth information can be used to indicate that the first IMS network is not included in one or more third IMS networks, or in other words, to indicate that establishing a connection between the user equipment and the first IMS network is not supported. If the first IMS network is not included in one or more third IMS networks, the session management network element can send the fourth information to the user equipment.

[0453] It is understandable that N1N2 messages may include information sent by the session management network element to the user equipment, that is, the fourth information may be included in the information sent by the session management network element to the user equipment.

[0454] One possible implementation is that the fourth piece of information includes session establishment rejection information. This rejection information may include message type information and / or parameter information of the session establishment rejection message.

[0455] One possible implementation is that the fourth information can be indication information, which can be used to indicate that establishing a connection between the user equipment and the first IMS network is not supported. For example, the indication information can be a single bit, multiple bits, or a string. When the indication information is a single bit, a value of 0 indicates that establishing a connection between the user equipment and the first IMS network is not supported. Alternatively, when the indication information is a single bit, a value of 1 indicates that establishing a connection between the user equipment and the first IMS network is not supported. When the indication information is multiple bits, one type of multiple bits can indicate that establishing a connection between the user equipment and the first IMS network is not supported. When the indication information is a string, one type of string can indicate that establishing a connection between the user equipment and the first IMS network is not supported.

[0456] Step 1412: The access and mobility management network element sends the fourth information to the user equipment.

[0457] For example, the access and mobility management network element receives the fourth information from the session management network element and sends a NAS message to the user equipment, the NAS message including the fourth information.

[0458] In other words, the fourth piece of information is sent by the session management network element to the user equipment through the access and mobility management network element.

[0459] It should be added that, in this embodiment of the application, the access and mobility management network element may pre-configure network information of one or more third IMS networks. After step 1401, the access and mobility management network element may determine whether the first IMS network is included in one or more third IMS networks based on the network information of the first IMS network in the session establishment request message. If so, the session management network element may be further selected (in which case step 1404 does not need to be executed). Otherwise, step 1412 may be executed, and the access and mobility management network element may send session establishment rejection information to the user equipment.

[0460] During the session request process, the user equipment (UE) sends the network information of the first IMS requested by the UE to the core network equipment. Based on this information, the core network equipment can determine whether one or more IMS networks connected to the non-public network accessed by the UE include the first IMS network. Essentially, the core network equipment determines whether an IMS network capable of providing IMS services to the UE exists among the one or more IMS networks connected to the non-public network accessed by the UE. If such an IMS network exists, the core network equipment can instruct the UE to request a connection with the proxy call network element corresponding to the first IMS network. In this approach, when an IMS network capable of providing IMS services exists among the one or more IMS networks connected to the UE's non-public network, the UE's request to establish a connection with the proxy call network element corresponding to the first IMS network helps reduce signaling overhead and network resource consumption.

[0461] It should be added that, in the embodiments of this application, the network information of the first IMS network, or the second IMS network, or the third IMS network may include one or more of the following: service provider identifier, network identifier, network domain name, data network name, and address information of the proxy calling network element. Here, the data network name may include one or more of the following: service provider identifier, network identifier, network domain name, and address information of the proxy calling network element. That is, in one possible manner, the network information of the first IMS network, or the second IMS network, or the third IMS network may include this data network name.

[0462] The various embodiments described herein can be independent solutions or combinations based on internal logic, and all such solutions fall within the protection scope of this application.

[0463] In the embodiments provided above, the methods provided by this application are described from the perspective of interaction between various devices / network elements. To implement the functions of the methods provided in the embodiments of this application, each device / network element may include hardware structures and / or software modules, implementing the above functions in the form of hardware structures, software modules, or a combination of hardware structures and software modules. Whether a particular function is executed in the form of hardware structures, software modules, or a combination of hardware structures and software modules depends on the specific application and design constraints of the technical solution.

[0464] The module division in this embodiment is illustrative and represents only one logical functional division; in actual implementation, other division methods may be used. Furthermore, the functional modules in the various embodiments of this application can be integrated into a single processor, exist as separate physical entities, or be integrated into a single module. The integrated modules described above can be implemented in hardware or as software functional modules.

[0465] Based on the above content and the same concept, Figure 15 This is a schematic diagram illustrating the structure of a possible communication device provided in this application. These communication devices can be used to implement the above-mentioned... Figures 6 to 10 The methods illustrated in the embodiments of the present invention can also achieve the functions of the session management network element, user equipment, policy control network element, or target proxy call network element, and thus can also realize the above-mentioned functions. Figures 6 to 10 The beneficial effects of the illustrated method embodiments are shown.

[0466] In this application, the communication device can be as follows: Figure 1 The session management network element, user equipment, policy control network element, or target agent call network element shown can also be a component (such as a chip or circuit) applied in the session management network element, user equipment, policy control network element, or target agent call network element.

[0467] like Figure 15 As shown, the communication device 1500 includes a processing module 1501 and a transceiver module 1502.

[0468] When the communication device 1500 is used to achieve the above Figures 6 to 10 When the session management network element of the method embodiment shown functions as follows:

[0469] The processing module 1501 is used to control the transceiver module 1502 to receive first information from the user equipment. The device and the user equipment are located on a non-public network connected to multiple IMS networks. The first information is used to instruct the user equipment to request a connection to a target IMS network. The target IMS network is one of the multiple IMS networks and is provided by a target service provider. The processing module 1501 is also used to determine first call information based on the first information. The first call information instructs a target proxy call network element and is used to establish a connection between the user equipment and the target IMS network. The processing module 1501 is also used to control the transceiver module 1502 to send the first call information to the user equipment.

[0470] In one possible implementation, the first information includes the identification information of the target service provider, and / or the first call information.

[0471] In one possible implementation, the first information is data network name information, which includes the identification information of the target service provider.

[0472] In one possible implementation, the target proxy call network element is located in the non-public network, and the processing module 1501 is further configured to control the transceiver module 1502 to send second information to the target proxy call network element or policy control network element; wherein, the second information includes the identification information of the user equipment and the identification information of the target service provider, and the second information is used to instruct the target proxy call network element to send the IMS message from the user equipment to the target query call network element of the target IMS network.

[0473] In one possible implementation, the second information further includes second call information for instructing the target query call element.

[0474] In one possible implementation, the target proxy call network element is located in the non-public network. The processing module 1501 is further configured to determine the second call information corresponding to the target service provider based on the correspondence between the service provider and the query call information; determine the target association relationship, which includes the association relationship between the user equipment identification information and the second call information, or the target association relationship includes the association relationship between the user equipment identification information, the second call information and the identification information of the target service provider; the processing module 1501 is further configured to control the transceiver module 1502 to send the target association relationship to the target proxy call network element or the policy control network element.

[0475] When the communication device 1500 is used to achieve the above Figures 6 to 10 When the user equipment of the method embodiment shown functions as follows:

[0476] The processing module 1501 is used to control the transceiver module 1502 to send first information to the session management network element. The device and the session management network element are located in a non-public network, which is connected to multiple IMS networks. The first information is used to indicate the target IMS network that the device requests to connect to. The target IMS network is one of the multiple IMS networks and is provided by a target service provider. The processing module 1501 is also used to control the transceiver module 1502 to receive first call information from the session management network element. The first call information indicates a target proxy call network element and is used to establish a connection between the device and the target IMS network.

[0477] In one possible implementation, the first information includes the identification information of the target service provider, and / or the first call information.

[0478] In one possible implementation, the first information is data network name information, which includes the identification information of the target service provider.

[0479] In one possible implementation, the data network name information is obtained by the processing module 1501 controlling the transceiver module 1502 from the access and mobility management network element, the session management network element, or the access network device.

[0480] In one possible implementation, the first information includes the first call information. Before the processing module 1501 controls the transceiver module 1502 to send the first information to the session management network element, it is also used to control the transceiver module 1502 to receive third information from the access network device. The third information includes the first service provider and the proxy call information corresponding to the first service provider. The proxy call information corresponding to the first service provider is the first call information.

[0481] In one possible implementation, the first information includes the first call information. Before the processing module 1501 controls the transceiver module 1502 to send the first information to the session management network element, it is also used to control the transceiver module 1502 to send a query request to the domain name system server and receive a query response from the domain name system server. The query request includes the identification information of the non-public network, and the query response includes the first call information. The target proxy call network element is located in the target IMS network and connected to the non-public network.

[0482] When the communication device 1500 is used to achieve the above Figures 6 to 10 When the policy control network element is functioning in the illustrated method embodiment, it is as follows:

[0483] The processing module 1501 is configured to control the transceiver module 1502 to receive second information from a session management network element. The second information includes the identification information of the user equipment and the identification information of the target service provider. The processing module 1501 is further configured to determine a target association relationship based on the correspondence between the service provider and the inquiry call information and the second information. The target association relationship includes the association relationship between the identification information of the user equipment and the second call information, or the target association relationship includes the association relationship between the identification information of the user equipment, the second call information, and the identification information of the target service provider. The second call information indicates a target inquiry call network element, the target inquiry call network element is located in a target IMS network, and the target inquiry call network element is connected to a target proxy call network element in a non-public network. The processing module 1501 is further configured to control the transceiver module 1502 to send the target association relationship to the target proxy call network element.

[0484] When the communication device 1500 is used to achieve the above Figures 6 to 10 When the target agent calls the network element in the method embodiment shown:

[0485] The processing module 1501 is used to control the transceiver module 1502 to receive IMS information from the user equipment, wherein the IMS information includes the identification information of the user equipment, and the target proxy call network element and the user equipment are located in a non-public network; the processing module 1501 is also used to determine second call information based on the target association relationship and the identification information of the user equipment, wherein the target association relationship includes the association relationship between the identification information of the user equipment and the second call information; the processing module 1501 is also used to control the transceiver module 1502 to send the IMS information to the target query call network element indicated by the second call information, wherein the target query call network element is located in the target IMS network.

[0486] In one possible implementation, before the processing module 1501 controls the transceiver module 1502 to receive IMS information from the user equipment, it is also configured to control the transceiver module 1502 to receive the target association relationship from the policy control network element or the session management network element.

[0487] In one possible implementation, before the processing module 1501 controls the transceiver module 1502 to receive IMS information from the user equipment, it is further configured to control the transceiver module 1502 to receive the identification information of the user equipment and the identification information of the target service provider from the policy control network element or the session management network element; and to determine the target association relationship based on the correspondence between the service provider and the inquiry call information.

[0488] In one possible implementation, the target association also includes the identification information of the target service provider.

[0489] Based on the above content and the same concept, Figure 15 The provided communication devices can also be used to achieve the above. Figures 11 to 14 The functions of the communication device or core network equipment shown in the method embodiment can also achieve the above-mentioned functions. Figures 11 to 14 The beneficial effects of the illustrated method embodiments are shown.

[0490] In this application, the communication device can be as follows: Figure 1 The communication device, session management network element, or access and mobility management network element shown may also be a component (such as a chip or circuit) applied in the communication device, session management network element, or access and mobility management network element.

[0491] When the communication device 1500 is used to achieve the above Figure 12 or Figure 14 The function of the communication device 1500 in the illustrated method embodiment is as follows:

[0492] In one possible implementation, the processing module 1501 is used to control the transceiver module 1502 to send network information of the first IMS network supported by the communication device 1500 to the core network device; the processing module 1501 is also used to control the transceiver module 1502 to receive fourth information from the core network device, the fourth information indicating whether it is supported to establish a connection between the communication device 1500 and the first IMS network.

[0493] In one possible implementation, the communication device 1500 sends network information of the first IMS network to the core network device through a registration process. The fourth information indicates support for establishing a connection between the communication device 1500 and the first IMS network. The processing module 1501 is further configured to: control the transceiver module 1502 to send session establishment request information to the core network device. The session establishment request message is used to establish a connection between the communication device 1500 and the first IMS network.

[0494] In one possible implementation, the communication device 1500 sends network information of the first IMS network to the core network device through a session establishment process. The fourth information indicates support for establishing a connection between the communication device 1500 and the first IMS network. The processing module 1501 is further configured to: obtain the address information of the proxy call network element corresponding to the first IMS network; and establish a connection with the proxy call network element according to the address information.

[0495] In one possible implementation, the communication device 1500 sends network information of the first IMS network to the core network device through a session establishment process. The fourth information indicates that establishing a connection between the communication device 1500 and the first IMS network is not supported. The fourth information includes session establishment rejection information.

[0496] In one possible implementation, the network information includes one or more of the following: service provider identifier, network identifier, network domain name, data network name, and address information of proxy call network element.

[0497] In one possible implementation, the fourth information includes one or more of the following: session establishment acceptance information, session establishment rejection information, service provider identifier, network identifier, network domain name, address information of proxy call network element, and data network name information.

[0498] When the communication device 1500 is used to achieve the above Figure 12 or Figure 14 When the core network device functions in the illustrated method embodiment:

[0499] In one possible implementation, the processing module 1501 controls the transceiver module 1502 to acquire network information of a first IMS network, wherein the first IMS network is an IMS network supported by the user equipment; the processing module 1501 controls the transceiver module 1502 to send fourth information to the user equipment, wherein the fourth information indicates whether it is supported to establish a connection between the user equipment and the first IMS network.

[0500] In one possible implementation, the processing module 1501 is specifically configured to: control the transceiver module 1502 to receive network information of the first IMS network from the user equipment through the registration process; the fourth information indicates support for establishing a connection between the user equipment and the first IMS network, and the processing module 1501 is further configured to: control the transceiver module 1502 to receive a session establishment request message from the user equipment.

[0501] In one possible implementation, the processing module 1501 is specifically configured to: receive network information of the first IMS network from the user equipment through the session establishment process control transceiver module 1502; the fourth information indicates support for establishing a connection between the user equipment and the first IMS network, the fourth information including session establishment acceptance information and / or address information of the proxy call network element corresponding to the first IMS network.

[0502] In one possible implementation, the processing module 1501 is specifically configured to: receive network information of the first IMS network from the user equipment through the session establishment process control transceiver module 1502; the fourth information indicates that the establishment of a connection between the user equipment and the first IMS network is not supported, and the fourth information includes session establishment rejection information.

[0503] In one possible implementation, the network information includes one or more of the following: service provider identifier, network identifier, network domain name, address information of proxy call network element, and data network name.

[0504] In one possible implementation, the fourth information includes one or more of the following: session establishment acceptance information, session establishment rejection information, service provider identifier, network identifier, network domain name, address information of proxy call network element, and data network name.

[0505] When the communication device 1500 is used to achieve the above Figure 11 or Figure 13 When the user equipment of the method embodiment shown functions as follows:

[0506] In one possible implementation, the processing module 1501 is used to control the transceiver module 1502 to acquire network information of one or more IMS networks, wherein the one or more IMS networks are connected to a non-public network accessed by the communication device 1500; the processing module 1501 is also used to determine that the one or more IMS networks include a first IMS network to which the communication device 1500 requests connection; and to establish a connection with the first IMS network based on the network information of the first IMS network.

[0507] In one possible implementation, the processing module 1501 is further configured to: control the transceiver module 1502 to send IMS capability information to the core network device, wherein the IMS capability information is used to indicate that the communication device 1500 supports establishing a connection with the IMS network.

[0508] In one possible implementation, the processing module 1501 is specifically used to control the transceiver module 1502 to send the IMS capability information to the core network device through a registration process or a session establishment process.

[0509] In one possible implementation, the IMS capability information includes network information of the first IMS network.

[0510] In one possible implementation, the processing module 1501 is specifically configured to: control the transceiver module 1502 to obtain network information of the one or more IMS networks from the core network device through a session establishment process; and control the transceiver module 1502 to obtain the address information of the proxy call network element corresponding to the first IMS network; and establish a connection with the proxy call network element according to the address information.

[0511] In one possible implementation, the processing module 1501 is specifically configured to: control the transceiver module 1502 to obtain network information of the one or more IMS networks from the core network device through a registration process; and control the transceiver module 1502 to send session establishment request information to the core network device according to the network information of the first IMS network, wherein the session establishment request information is used to establish a connection between the communication device 1500 and the first IMS network.

[0512] In one possible implementation, the network information of the one or more IMS networks is included in the broadcast message of the access network device.

[0513] In one possible implementation, the network information includes one or more of the service provider's identifier, network identifier, network domain name, data network name, and address information of the proxy call network element.

[0514] When the communication device 1500 is used to achieve the above Figure 11 or Figure 13 When the core network device of the method embodiment shown functions as follows:

[0515] In one possible implementation, the processing module 1501 is used to control the transceiver module 1502 to acquire network information of one or more IMS networks, wherein the one or more IMS networks are connected to a non-public network accessed by the user equipment; the processing module 1501 is also used to control the transceiver module 1502 to send the network information of one or more IMS networks to the user equipment.

[0516] In one possible implementation, the processing module 1501 is further configured to: control the transceiver module 1502 to receive IMS capability information of the user equipment from the user equipment, the IMS capability information being used to indicate that the user equipment supports establishing a connection with the IMS network.

[0517] In one possible implementation, the processing module 1501 is specifically used to: control the transceiver module 1502 to receive the IMS capability information of the user equipment from the user equipment through a registration process or a session establishment process.

[0518] In one possible implementation, the IMS capability information includes network information of a first IMS network, which is the IMS network to which the user equipment requests connection.

[0519] In one possible implementation, the processing module 1501 is specifically configured to: control the transceiver module 1502 to send network information of the one or more IMS networks to the user equipment through a registration process; and control the transceiver module 1502 to receive a session establishment request message from the user equipment; the session establishment request message is used to establish a connection between the user equipment and the first IMS network.

[0520] In one possible implementation, the network information includes one or more of the following: service provider identifier, network identifier, network domain name, data network name, and address information of proxy call network element.

[0521] like Figure 16 The image shown is of the apparatus 1600 provided in an embodiment of this application. Figure 16 The device shown can be Figure 11 The illustrated device is implemented using one type of hardware circuit.

[0522] This communication device can be used in the flowchart shown above to perform the above... Figures 6 to 10 The illustrated method embodiment demonstrates the functions of the session management network element, user equipment, policy control network element, or target agent call network element.

[0523] This communication device can also be used in the flowchart shown above to perform the above... Figures 11 to 14 The method embodiments shown include user equipment, session management network element, or access and mobility management network element.

[0524] For ease of explanation, Figure 16 Only the main components of the communication device are shown.

[0525] The device 1600 may further include at least one memory 1630 for storing program instructions and / or data. The memory 1630 is coupled to the processor 1620. The coupling in this embodiment is an indirect coupling or communication connection between devices, units, or modules, and may be electrical, mechanical, or other forms, for information exchange between devices, units, or modules. The processor 1620 may operate in conjunction with the memory 1630. The processor 1620 may execute program instructions stored in the memory 1630. At least one of the at least one memory may be included in the processor.

[0526] Figure 16 The illustrated device 1600 includes at least one processor 1620 and a communication interface 1610. The processor 1620 is used to execute instructions or programs stored in the memory 1630. When the instructions or programs stored in the memory 1630 are executed, the processor 1620 is used to perform the operations performed by the processing module 1501 in the above embodiment, and the communication interface 1610 is used to perform the operations performed by the transceiver module 1502 in the above embodiment.

[0527] In this embodiment, the communication interface can be a transceiver, circuit, bus, module, or other type of communication interface. In this embodiment, when the communication interface is a transceiver, the transceiver can include an independent receiver, an independent transmitter, or a transceiver integrating transceiver functions, or simply a communication interface.

[0528] Device 1600 may further include a communication line 1640. The communication interface 1610, processor 1620, and memory 1630 can be interconnected via the communication line 1640. The communication line 1640 can be a peripheral component interconnect (PCI) bus or an extended industry standard architecture (EISA) bus, etc. The communication line 1640 can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 16 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0529] Based on the above content and the same concept, this application provides a chip system, including: a processor coupled to a memory, the memory being used to store programs or instructions, wherein when the program or instructions are executed by the processor, the chip system enables the aforementioned functionality. Figures 6 to 10 The illustrated method embodiment demonstrates the functions of a session management network element, user equipment, policy control network element, or target proxy call network element. Alternatively, the chip system can be configured to implement the aforementioned functions. Figures 11 to 14The illustrated method embodiments demonstrate the functions of user equipment, session management network element, or access and mobility management network element.

[0530] Optionally, the chip system also includes an interface circuit for exchanging code instructions with the processor.

[0531] Optionally, the chip system may include one or more processors, which can be implemented in hardware or software. When implemented in hardware, the processor may be a logic circuit, integrated circuit, etc. When implemented in software, the processor may be a general-purpose processor that reads software code stored in memory.

[0532] Optionally, the chip system may contain one or more memories. These memories may be integrated with the processor or disposed separately. For example, the memory may be a non-transitory processor, such as a read-only memory (ROM), which may be integrated with the processor on the same chip or disposed on separate chips.

[0533] Based on the above content and the same concept, embodiments of this application provide a computer-readable storage medium storing a computer program or instructions thereon, which, when executed, causes a computer to perform the aforementioned... Figures 6 to 10 The illustrated method embodiment demonstrates the functions of a session management network element, user equipment, policy control network element, or target proxy call network element. Alternatively, it causes a computer to perform the above-described functions. Figures 11 to 14 The illustrated method embodiments demonstrate the functions of user equipment, session management network element, or access and mobility management network element.

[0534] Based on the above content and the same concept, embodiments of this application provide a computer program product that, when a computer reads and executes the computer program product, causes the computer to perform the above-mentioned... Figures 6 to 10 The illustrated method embodiment demonstrates the functions of a session management network element, user equipment, policy control network element, or target proxy call network element. Alternatively, it allows a computer to perform the aforementioned actions. Figures 11 to 14 The illustrated method embodiments demonstrate the functions of user equipment, session management network element, or access and mobility management network element.

[0535] Based on the above content and the same concept, embodiments of this application provide a communication system, which includes the above-described... Figures 6 to 10 The method embodiments shown may include one or more of the following: session management network element, user equipment, policy control network element, or target agent call network element.

[0536] Based on the above content and the same concept, embodiments of this application provide a communication system, which includes the above-described... Figures 11 to 14The illustrated method embodiment includes one or more of the session management network element, user equipment, and access and mobility management network element.

[0537] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, at least one of a, b, or c can represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. In the textual description of this application, the character " / " generally indicates an "or" relationship between the preceding and following related objects; in the formulas of this application, the character " / " indicates a "division" relationship between the preceding and following related objects.

[0538] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, optical storage, etc.) containing computer-usable program code.

[0539] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to this application. It should be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0540] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1The function specified in one or more boxes.

[0541] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A communication method, characterized in that, include: The session management network element receives first information from the user equipment. The session management network element and the user equipment are located in a communication network. The communication network is connected to multiple IP Multimedia Subsystem (IMS) networks. The first information is used to indicate the target IMS network that the user equipment requests to connect to. The target IMS network is one of the multiple IMS networks and is provided by a target service provider. The session management network element determines the first call information based on the first information. The first call information instructs the target agent call network element and is used to establish a connection between the user equipment and the target IMS network. The session management network element sends the first call information to the user equipment; The first information is data network name information, which includes the identification information of the target service provider; The session management network element determines the first call information based on the first information, including: The session management network element determines the proxy call information corresponding to the identification information of the target service provider in the first correspondence relationship as the first call information based on the identification information of the target service provider and the first correspondence relationship. The first correspondence relationship includes the correspondence relationship between the identification information of multiple service providers and multiple proxy call information.

2. The method as described in claim 1, characterized in that, The first call information is the address information of the target agent calling network element.

3. The method as described in claim 1, characterized in that, The target agent calling network element is located in the communication network, and the method further includes: The session management network element sends the second information to the target agent call network element or policy control network element; The second information includes the identification information of the user equipment and the identification information of the target service provider. The second information is used to instruct the target proxy call element to send the IMS message from the user equipment to the target query call element of the target IMS network.

4. The method as described in claim 3, characterized in that, The second information also includes second call information for instructing the target query call element.

5. The method as described in claim 1, characterized in that, The target agent calling network element is located in the communication network, and the method further includes: The session management network element determines the second call information corresponding to the target service provider based on the correspondence between the service provider and the query call information; The session management network element determines the target association relationship, which includes the association relationship between the user equipment's identification information and the second call information, or the target association relationship includes the association relationship between the user equipment's identification information, the second call information, and the target service provider's identification information. The session management network element sends the target association relationship to the target agent call network element or policy control network element.

6. The method according to any one of claims 1 to 5, characterized in that, The communication network is a non-public network.

7. A communication method, characterized in that, include: A communication device sends first information to a session management network element. The communication device is a user equipment or a component of a user equipment. The communication device and the session management network element are located in a communication network. The communication network is connected to multiple IP Multimedia Subsystem (IMS) networks. The first information is used to indicate the target IMS network that the communication device requests to connect to. The target IMS network is one of the multiple IMS networks and is provided by a target service provider. The communication device receives first call information from the session management network element, the first call information instructs the target proxy call network element, and the first call information is used to establish a connection between the communication device and the target IMS network; The first information is data network name information, which includes the identification information of the target service provider; The identification information of the target service provider and the first correspondence relationship are used to determine the first call information. The first correspondence relationship includes the correspondence between the identification information of multiple service providers and multiple proxy call information. The proxy call information corresponding to the identification information of the target service provider in the first correspondence relationship is the first call information.

8. The method as described in claim 7, characterized in that, The first call information is the address information of the target agent calling network element.

9. The method as described in claim 7, characterized in that, The data network name information is obtained by the communication device from the access and mobility management network element, the session management network element, or the access network device.

10. The method as described in claim 7, characterized in that, The first information includes the first call information. Before the communication device sends the first information to the session management network element, it further includes: The communication device receives third information from the access network device, the third information including the target service provider and the proxy call information corresponding to the target service provider, the proxy call information corresponding to the target service provider being the first call information.

11. The method as described in claim 7, characterized in that, The first information includes the first call information. Before the communication device sends the first information to the session management network element, it further includes: The communication device sends a query request to the Domain Name System server, the query request including the identification information of the communication network; The communication device receives a query response from the Domain Name System server. The query response includes the first call information, and the target proxy call element indicated by the first call information is located in the target IMS network and connected to the communication network.

12. The method according to any one of claims 7 to 11, characterized in that, The communication network is a non-public network.

13. A communication device, characterized in that, include: The processing module controls the transceiver module to receive first information from the user equipment. The device and the user equipment are located in a communication network, which is connected to multiple IP Multimedia Subsystem (IMS) networks. The first information is used to instruct the user equipment to request a connection to a target IMS network, which is one of the multiple IMS networks and is provided by a target service provider. The processing module is further configured to determine first call information based on the first information, wherein the first call information indicates a target proxy call network element, and the first call information is used to establish a connection between the user equipment and the target IMS network; The processing module is also used to control the transceiver module to send the first call information to the user equipment; The first information is data network name information, which includes the identification information of the target service provider; When the processing module determines the first call information based on the first information, it is specifically used to determine the proxy call information corresponding to the identification information of the target service provider in the first correspondence relationship as the first call information, based on the identification information of the target service provider and the first correspondence relationship. The first correspondence relationship includes the correspondence relationship between the identification information of multiple service providers and multiple proxy call information.

14. The apparatus as claimed in claim 13, characterized in that, The first call information is the address information of the target agent calling network element.

15. The apparatus as claimed in claim 13, characterized in that, The target proxy call network element is located in the communication network, and the processing module is further configured to control the transceiver module to send second information to the target proxy call network element or policy control network element; wherein, the second information includes the identification information of the user equipment and the identification information of the target service provider, and the second information is used to instruct the target proxy call network element to send the IMS message from the user equipment to the target query call network element of the target IMS network.

16. The apparatus as claimed in claim 15, characterized in that, The second information also includes second call information for instructing the target query call element.

17. The apparatus as claimed in claim 13, characterized in that, The target proxy call network element is located in the communication network, and the processing module is further configured to determine the second call information corresponding to the target service provider based on the correspondence between the service provider and the inquiry call information; The target association relationship is determined, which includes the association relationship between the identification information of the user equipment and the second call information, or the target association relationship includes the association relationship between the identification information of the user equipment, the second call information and the identification information of the target service provider; the processing module is further configured to control the transceiver module to send the target association relationship to the target proxy call network element or policy control network element.

18. The apparatus according to any one of claims 13 to 17, characterized in that, The communication network is a non-public network.

19. A communication device, characterized in that, include: The processing module controls the transceiver module to send first information to the session management network element. The device and the session management network element are located in a communication network, which is connected to multiple IP Multimedia Subsystem (IMS) networks. The first information is used to indicate the target IMS network that the device requests to connect to. The target IMS network is one of the multiple IMS networks and is provided by a target service provider. The processing module is also configured to control the transceiver module to receive first call information from the session management network element, the first call information instructing the target agent call network element, and the first call information is used to establish a connection between the device and the target IMS network; The first information is data network name information, which includes the identification information of the target service provider; The identification information of the target service provider and the first correspondence relationship are used to determine the first call information. The first correspondence relationship includes the correspondence between the identification information of multiple service providers and multiple proxy call information. The proxy call information corresponding to the identification information of the target service provider in the first correspondence relationship is the first call information.

20. The apparatus as claimed in claim 19, characterized in that, The first call information is the address information of the target agent calling network element.

21. The apparatus as claimed in claim 19, characterized in that, The data network name information is obtained by the processing module from the access and mobility management network element, the session management network element, or the access network device, through the transceiver module.

22. The apparatus as claimed in claim 19, characterized in that, The first information includes the first call information. Before the processing module controls the transceiver module to send the first information to the session management network element, it is also used to control the transceiver module to receive third information from the access network device. The third information includes the target service provider and the proxy call information corresponding to the target service provider. The proxy call information corresponding to the target service provider is the first call information.

23. The apparatus as claimed in claim 19, characterized in that, The first information includes the first call information. Before the processing module controls the transceiver module to send the first information to the session management network element, it is also used to control the transceiver module to send a query request to the domain name system server. The query request includes the identification information of the communication network and receives a query response from the domain name system server. The query response includes the first call information. The target proxy call network element is located in the target IMS network and connected to the communication network.

24. The apparatus according to any one of claims 19 to 23, characterized in that, The communication network is a non-public network.

25. A communication device, characterized in that, The device includes a processor and a communication interface, wherein the communication interface is used to receive signals from other communication devices besides the communication device and transmit them to the processor, or to send signals from the processor to other communication devices besides the communication device. The processor is used to implement the method as described in any one of claims 1 to 6, or to implement the method as described in any one of claims 7 to 12, through logic circuits or execution code instructions.

26. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program or instructions that, when executed by a communication device, implement the method as described in any one of claims 1 to 6, or are used to implement the method as described in any one of claims 7 to 12.

27. A computer program product, characterized in that, The computer program product includes a computer program or instructions that, when executed by a communication device, implement the method as described in any one of claims 1 to 6, or are used to implement the method as described in any one of claims 7 to 12.

28. A communication system, characterized in that, include: The apparatus of any one of claims 13 to 18, and the apparatus of any one of claims 19 to 24.

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