Communication method and communication apparatus

Abstract

The present application provides a communication method and a communication apparatus. The communication method comprises: a first access network device sends a first connection message by means of a first relay transmission path, wherein the first connection message is used for instructing a first core network element to provide a service for a terminal device, the first relay transmission path comprises a message transmission path between the first access network device and a second access network device, the second access network device is connected to the first core network element, or the second access network device is connected to a second core network element, and the second core network element is used for determining the first core network element. By means of the method in embodiments of the present application, a service request process of the terminal device can be implemented when interface connection between the access network device and the core network element is limited.

Description

Communication method and communication device

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on December 22, 2023, with application number 202311792331.9 and title “Communication Method and Communication Device,” the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of communications, and more particularly, to a communication method and a communication device. Background Art

[0003] At present, user equipment (UE) or 5G core network (5th generation core network, 5GC) in signaling idle state (CM-IDLE) can use the service request process to request to establish a secure connection to the core network element such as access and mobility management function (AMF). In the service request process, when the UE and the core network element such as AMF are in signaling idle state (CM-IDLE) or signaling connected state (CM-CONNECTED), the user plane connection is activated for the established PDU (protocol data unit) session through the service request. For example, after establishing a signaling connection with the AMF, the UE or the core network can send a signaling message to the session management function (SMF) through the AMF to establish a PDU session.

[0004] However, if the connection between the base station where the UE is located, such as the radio access network (RAN), and the core network element, such as the above-mentioned AMF, is limited, the UE cannot complete the above-mentioned service request process, and the core network element's paging operation for the UE cannot be reached normally.

[0005] Summary of the Invention

[0006] The present application provides a communication method and a communication device, which can implement an uplink service request process of a terminal device when the interface connection between the access network device and the core network element is limited.

[0007] In a first aspect, a communication method is provided, which can be applied to an access network device or a component of the access network device. For simplicity, the access network device is used as an example for description.

[0008] The method includes: the first access network device sends a first connection message through a first relay transmission path, the first connection message is used to instruct the first core network network element to provide services for the terminal device, the first relay transmission path includes a message transmission path between the first access network device and the second access network device, the second access network device is connected to the first core network network element, or the second access network device is connected to the second core network network element, and the second core network network element is used to determine the first core network network element.

[0009] The communication method of the first aspect is applied to an uplink service request process in a core network. During the uplink service request process, a terminal device or UE is in an idle state or needs to establish a connection to the core network. In this case, the terminal device sends a service request message to an access network device, such as the first access network device mentioned above, to initiate a service request.

[0010] In combination with the first aspect, in some implementations of the first aspect, there is limited connectivity between the first access network device and the first core network element.

[0011] It should be understood that the application scenario of the communication method of the first aspect is a scenario where the interface connection between the first access network device and the first core network network element is limited, for example, the N2 interface connection between the access network device RAN and the access and mobility management network element AMF is limited, or the N3 interface connection between the access network device RAN and the user plane network element UPF is limited. In this case, when the first access network device receives the first service request message sent by the terminal device, it cannot send the first connection message directly to the first core network network element, and thus cannot establish the uplink service request process.

[0012] For example, limited interface connectivity can be caused by an interface being unresponsive, such as an access network device sending a data packet to a core network element, but the core network element does not respond. Alternatively, the interface may be experiencing severe packet loss, or transmission limitations, such as poor satellite link conditions resulting in very slow transmission speeds. Furthermore, scenarios where interface connectivity is limited include, but are not limited to, connection failures, connection failures, and so on.

[0013] Therefore, specifically, in the communication method shown in the first aspect, the first connection message sent by the first access network device can be forwarded through the interface connection of the complete second access network device, forwarded to the core network network element, and finally the first core network network element can receive the first connection message, and then the first core network network element can provide services to the terminal device, so that the uplink service request of the terminal device is still available.

[0014] The first access network device is the access network device to which the terminal device is currently connected, and may also be referred to as a source RAN (source RAN) to reflect that the terminal device establishes a connection with the core network through the first access network device.

[0015] Specifically, the first relay transmission path includes a message transmission path between the first access network device and the second access network device. For example, the first access network device can establish a connection with the second access network device by random access or a pre-configured spare interface. At this time, the first connection message can directly reach the second access network device through the first relay transmission path. For another example, the first access network device establishes a connection with the third access network device by random access or a pre-configured spare interface, and the third access network device establishes a connection with the second access network device by random access or a pre-configured spare interface. At this time, the first relay transmission path is from the first access network device to the third access network device and then to the second access network device. The first access network device, the second access network device and the third access network device (optional) can be connected through Xn or other horizontal device interfaces.

[0016] It is worth noting that the first relay transmission path is the path by which the message can reach the second access network device from the first access network device. The networking between multiple access network devices given above is only an example. The first relay transmission path can also be a tunnel between the first access network device and the second access network device, etc.

[0017] Through the above method, when the connection between the first access network device and the first core network network element is limited, the first access network device implements the uplink service request process of the terminal device through the first relay transmission path, thereby improving the network resilience and reliability of the core network.

[0018] In combination with the first aspect, in certain implementations of the first aspect, before the first access network device sends the first connection message, the method also includes: the first access network device receives a first service request message from the terminal device, and the first service request message is used to indicate a request to the core network network element to provide service to the terminal device.

[0019] Optionally, in an embodiment of the present application, the first service request message may include an AN parameter, which is parameter information sent by the terminal device to the first access network device. The AN parameter may include identification information of the terminal device, for example, a temporary mobile subscriber identity (TMSI) of the terminal device, such as a short term mobile subscriber identity (S-TMSI). The first service request information may also include activated PDU sessions, allocated PDU sessions, etc., which are not limited in this application.

[0020] In combination with the first aspect, in some implementations of the first aspect, the first connection message includes identification information of the terminal device, identification information of the first access network device, and path indication information, and the path indication information is used to indicate the first relay transmission path.

[0021] In combination with the first aspect, in some implementations of the first aspect, the first connection message further includes identification information of the service request initiated by the terminal device.

[0022] Among them, the identification information of the first access network device can be the ID of the first access network device, which is used to indicate the access network device for establishing the service request process, or to indicate which access network device the first connection message is sent to; the identification information of the terminal device can be the TMSI of the terminal device, which is used to indicate to the first core network network element the terminal device that needs to provide service; the path indication information is used to indicate the above-mentioned first relay transmission path.

[0023] Exemplarily, the path indication information may be the ID of each access network device in the first relay transmission path, such as the group ID of the consensus group or the ID of the entire RAN (e.g., the gNB ID), or the routing information of each RAN, such as an IP address or MAC address. Furthermore, communication devices along the first relay transmission path can use the path indication information to find the corresponding next node. In some embodiments of the present application, the communication devices in the first relay transmission path may vary in the path indication information. For example, when a first connection message is sent from a first access network device to a third access network device, the third access network device may determine, based on the connection status between the third access network device and the second access network device or core network element, whether to send the first connection message to the second access network device as indicated by the original path indication information, or to modify the path indication information and forward the first connection message to another access network device or directly to a core network element connected to the second access network device. Furthermore, the path indication information may indicate one or more relay transmission paths, including the first relay transmission path.

[0024] Exemplarily, the identification information of the service request may be an ID of the service request, which is used to identify which service request it is, so as to subsequently locate the service request initiated by the terminal device to the first core network element from multiple service requests.

[0025] In combination with the first aspect, in certain implementations of the first aspect, the method further includes: the first access network device receives a first connection response message through the first relay transmission path, the first connection response message including identification information of the terminal device, identification information of the first access network device, and at least one of path indication information, the path indication information being used to indicate the first relay transmission path.

[0026] Specifically, the first connection response message is used to indicate the service provided by the second core network element, such as data provided by the second core network element.

[0027] In combination with the first aspect, in certain implementations of the first aspect, before the first access network device sends the first connection message, the method also includes: the first access network device sends a first relay service request message, and the first relay service request message is used to indicate that the first access network device requests to send the first connection message via relay transmission; the first access network device receives a first relay service request response message, and the first relay service request response message includes path indication information, and the path indication information is used to indicate the first relay transmission path.

[0028] Optionally, the relay service request message may include identification information of the terminal device, such as TMSI.

[0029] The first access network device requests path indication information from the leader node in the consensus group by sending a relay service request message, so as to send a first connection message. After receiving the relay service request message, the leader node sends a first relay service request response message including the path indication information.

[0030] In combination with the first aspect, in certain implementations of the first aspect, the method also includes: the first access network device receives a connection status request message, which is used to request determination of the connection relationship between the first access network device and one or more access network devices; the first access network device sends a connection status feedback message, which includes the connection relationship between the first access network device and at least one access network device.

[0031] Specifically, the connection status request message is used to request the first access network device to determine the connection relationship between it and other access network devices. In other words, the connection status request message is used to request the first access network device to determine which access network devices are connected to the first access network device or which access network devices the first access network device is connected to. The first access network device determines the connection relationship and feeds back a connection status feedback message to the leader node. Specifically, the connection status feedback message includes which access network devices are connected to the third access network device or which access network devices the third access network device is connected to. In other words, the connection status feedback message includes at least one access network device, and the at least one access network device has a connection relationship with the third access network device that is connected to or is connected to.

[0032] Optionally, the connection status feedback message may include a connection relationship or a message transmission path, for example, the third access network device is connected to the second access network device (or, the third access network device->the second access network device).

[0033] In combination with the first aspect, in certain implementations of the first aspect, the connection status request message includes group identification information and / or connection attribute information of a first consensus group, the first consensus group includes multiple access network devices, the multiple access network devices include the first access network device and the at least one access network device, and the connection attribute information includes at least one of connection bandwidth, delay, connection type, jitter, time taken to restore the connection, and whether there is security protection.

[0034] The group identifier of the consensus group is used to ensure that the access network device in the connection status feedback information is the access network device in the consensus group.

[0035] In combination with the first aspect, in some implementations of the first aspect, the first relay service request message includes identification information of the terminal device.

[0036] In combination with the first aspect, in certain implementations of the first aspect, before the first access network device sends the first connection message, the method also includes: the first access network device determines the first relay transmission path based on the connection relationship between multiple access network devices included in the first consensus group, and the multiple access network devices include the first access network device and the second access network device.

[0037] The first access network device determines a first relay transmission path based on the received connection status feedback information. Exemplarily, the connection status feedback information received by the first access network device from the third access network device is "third access network device -> second access network device," and the connection status feedback information received by the first access network device from the second access network device is "second access network device -> second core network network element." Consequently, the first access network device determines the first relay transmission path as "first access network device -> third access network device -> second access network device" or "first access network device -> third access network device -> second access network device -> second core network network element."

[0038] Optionally, the path indication information may be the above-mentioned path description "first access network device -> third access network device -> second access network device", may be the group identifier or the whole network identifier of each access network device (such as the ID of the gNB), or may be the routing information of each access network device such as an IP address or a MAC address.

[0039] In combination with the first aspect, in certain implementations of the first aspect, the method further includes: the first access network device sends a connection status request message to an access network device among the multiple access network devices except the first access network device, and the connection status request message is used to request determination of the connection relationship between the multiple access network devices; the first access network device receives a connection status feedback message, and the connection status feedback message includes the connection relationship between the multiple access network devices.

[0040] In combination with the first aspect, in certain implementations of the first aspect, after the first access network device sends the first connection message, the method also includes: the first access network device receives a first paging request message through the first relay transmission path, and the first paging request message is used to request to initiate paging to the terminal device.

[0041] In combination with the first aspect, in some implementations of the first aspect, the first paging request message includes identification information of the terminal device.

[0042] In combination with the first aspect, in certain implementations of the first aspect, when the first access network device successfully initiates paging to the terminal device, the method also includes: the first access network device sends a paging success notification message through the first relay transmission path, and the paging success notification message is used to notify the first core network network element to instruct the terminal device to perform a paging action.

[0043] In combination with the first aspect, in some implementations of the first aspect, the second access network device is connected to the first core network element or the second core network element through a non-terrestrial communication network NTN.

[0044] Optionally, the interface between the second access network device and the second core network network element can be implemented through a non-terrestrial network (NTN) communication system, such as a satellite communication network, a high altitude platform system (HAPS) and an air-to-ground network. For example, a satellite communication system may include a satellite, and there is a terminal device on the satellite to communicate with a ground base station. Among them, the satellite may refer to a non-ground base station or non-ground equipment such as an unmanned aerial vehicle, a hot air balloon, a low-orbit satellite, a medium-orbit satellite, and a high-orbit satellite. The NTN communication system can be deployed alone or as a supplement to the ground network. In this way, when there can be one or more connection means between the second access network device and the second core network network element, even if the original interface connection is limited, it can be switched to a satellite connection, etc., thereby ensuring that the interface connection between the second access network device and the second core network network element is complete.

[0045] In a second aspect, a communication method is provided, which can be applied to an access network device or a component of an access network device. For simplicity, the access network device is used as an example for description.

[0046] The method includes: the second access network device receives a first paging request message from the first core network network element or the second core network network element, the first paging request message is used to request the first access network device to page the terminal device so that the first core network network element provides services to the terminal device, the second access network device is connected to the first core network network element, or the second access network device is connected to the second core network element, the second core network element is used to forward the first paging request message sent by the first core network network element; the second access network device sends the first paging request message through a first relay transmission path, and the first relay transmission path includes a message transmission path between the first access network device and the second access network device.

[0047] In combination with the second aspect, in some implementations of the second aspect, there is limited connectivity between the first access network device and the first core network element.

[0048] Optionally, the first paging request message may include identification information of the uplink service request and / or identification information of the terminal device. The identification information of the uplink service request is used to indicate the uplink service request corresponding to the downlink service request and is used to determine the first access network device for the uplink service request, and the identification information of the terminal device is used to determine to which terminal device the paging is to be initiated.

[0049] The communication method described in the second aspect is applied to a downlink service request process in a core network. During the downlink service request process, the core network needs to initiate paging to a terminal device through an access network device. However, when the interface connection between the first access network device and the first core network element is limited, the paging request from the core network cannot reach the first access network device, and thus cannot instruct the first access network device to initiate paging to the terminal device.

[0050] Therefore, specifically, in the communication method shown in the second aspect, the first paging request message sent by the first core network network element can be forwarded by connecting a complete second access network device through an interface, forwarded to the first access network device, and finally the first access network device initiates paging to the terminal device, and then the terminal device can perform the paging operation, so that the downlink service request of the core network is still available.

[0051] The second access network device is an access network device with a complete interface connection with a core network element, and may also be referred to as a target RAN (target RAN).

[0052] In combination with the second aspect, in certain implementations of the second aspect, the method also includes: the second access network device determines the first access network device corresponding to the first service request message based on the log information, the first service request message is used to indicate the request core network network element to provide service to the terminal device, the log information includes a mapping relationship between at least one access network device and at least one service request message, and each access network device in the at least one access network device receives a corresponding service request message from the terminal device.

[0053] For example, when a terminal device initiates a first uplink service request, it accesses access network device A. When the terminal device initiates a second uplink service request, it accesses access network device B. The second access network device (leader node) may record in log information the mapping relationship between the first uplink service request and access network device A, and between the second uplink service request and access network device B. Furthermore, the second access network device may determine the first access network device corresponding to the uplink service request based on the identification information of the uplink service request in the paging request message.

[0054] Optionally, the above mapping relationship may further include a relay transmission path or path indication information used when requesting an uplink service.

[0055] In combination with the second aspect, in some implementations of the second aspect, the log information further includes path indication information, where the path indication information is used to indicate the first relay transmission path.

[0056] In combination with the second aspect, in certain implementations of the second aspect, the method also includes: the second access network device receives the log information from the access network device in the first consensus group, the first consensus group includes multiple access network devices, and the multiple access network devices include the first access network device and the second access network device.

[0057] In combination with the second aspect, in certain implementations of the second aspect, the method also includes: the second access network device receives path indication information from an access network device in a first consensus group, the path indication information being used to indicate the first relay transmission path, the first consensus group including multiple access network devices, and the multiple access network devices including the first access network device and the second access network device.

[0058] It should be understood that, in the case where the log information does not include path indication information or the first relay transmission path, the second access network device acts as the leader node, and by synchronizing the log information to other nodes in the consensus group, the other nodes can initiate a search request to the second access network device (leader node) based on the mapping relationship between the access network device and the uplink service request in the log information, for searching for the path indication information or the first relay transmission path. In the case where the log information includes path indication information or the first relay transmission path, the other nodes in the consensus group can directly forward the first paging request message based on the path indication information or the first relay transmission path.

[0059] In combination with the second aspect, in certain implementations of the second aspect, the method also includes: the second access network device sends a path request message, which is used to determine the first relay transmission path; the second access network device receives path indication information from the access network device in the first consensus group, including: the second access network device receives a path request response message from the access network device in the first consensus group, and the path request response message includes the path indication information.

[0060] It should be understood that the path indication information may not be recorded in the local uplink history record or the routing information may have expired. At this time, the access network device serving as the leader node cannot determine the first relay transmission path, which in turn causes the second access network device to be unable to send the first paging request message through the first relay transmission path.

[0061] Therefore, specifically, the first relay transmission path can be re-determined through the fault-tolerant consensus algorithm. Optionally, if there is no consensus group and leader node at this time, the process of establishing a consensus group and electing a leader node can be retriggered.

[0062] In combination with the second aspect, in certain implementations of the second aspect, the method also includes: the second access network device receives a first connection message through a first relay transmission path, and the first connection message is used to instruct the first core network network element to provide services for the terminal device; the second access network device sends the first connection message to the first core network network element or the second core network element.

[0063] In combination with the second aspect, in some implementations of the second aspect, the first connection message includes identification information of the terminal device, identification information of the first access network device, and path indication information, and the path indication information is used to indicate the first relay transmission path.

[0064] In combination with the second aspect, in some implementations of the second aspect, the first connection message further includes identification information of the service request initiated by the terminal device.

[0065] In combination with the second aspect, in some implementations of the second aspect, the method also includes: the second access network device receives a first relay service request message, and the first relay service request message is used to indicate that the first access network device requests to send the first connection message via relay transmission; the second access network device sends a first relay service request response message, and the first relay service request response message includes path indication information, and the path indication information is used to indicate the first relay transmission path.

[0066] In combination with the second aspect, in some implementations of the second aspect, the first relay service request message includes identification information of the terminal device.

[0067] In combination with the second aspect, in certain implementations of the second aspect, before the second access network device receives the first connection message, the method also includes: the second access network device determines the first relay transmission path based on the connection relationship between multiple access network devices included in the first consensus group, and the multiple access network devices include the first access network device and the second access network device.

[0068] In combination with the second aspect, in certain implementations of the second aspect, the method further includes: the second access network device sends a connection status request message to an access network device among the multiple access network devices except the second access network device, and the connection status request message is used to request determination of the connection relationship between the multiple access network devices; the second access network device receives a connection status feedback message, and the connection status feedback message includes the connection relationship between the multiple access network devices.

[0069] In combination with the second aspect, in certain implementations of the second aspect, the method also includes: the second access network device receives a connection status request message, which is used to request determination of the connection relationship between the second access network device and one or more access network devices; the second access network device sends a connection status feedback message, which includes the connection relationship between the second access network device and at least one access network device.

[0070] In combination with the second aspect, in certain implementations of the second aspect, the connection status request message includes group identification information and / or connection attribute information of a first consensus group, the first consensus group includes multiple access network devices, the multiple access network devices include the second access network device and the at least one access network device, and the connection attribute information includes at least one of connection bandwidth, delay, connection type, jitter, time taken to restore the connection, and whether there is security protection.

[0071] The specific scheme description of the first connection message, the first relay service request message, the connection status request message, and the connection status feedback message can refer to the first aspect and will not be repeated here.

[0072] In a third aspect, a communication method is provided, which can be applied to an access network device or a component of an access network device. For simplicity, the access network device is used as an example for description.

[0073] The method includes: determining a first relay transmission path, the first relay transmission path including a message transmission path between the first access network device and the second access network device, the second access network device being connected to the first core network network element, or the second access network device being connected to the second core network network element, the second core network network element being used to determine the first core network network element; and sending a first connection message through the first relay transmission path, the first connection message being used to instruct the first core network network element to provide services for the terminal device.

[0074] In combination with the third aspect, in certain implementations of the third aspect, there is limited connectivity between the first access network device and the first core network element.

[0075] It should be understood that the communication method of the third aspect is applied to the leader node in a consensus group, wherein the consensus group includes multiple access network devices, such as a first access network device and a second access network device, and the leader node can be any access network device in the consensus group.

[0076] The prerequisite for establishing a consensus group is that all access network devices between the first access network device and the second access network device (including the first access network device and the second access network device) are directly or indirectly connected to or connected to one or more other access network devices, and therefore all access network devices are capable of direct or indirect (multi-hop) connections. In other words, a necessary condition for networking is that routes between access network devices are reachable.

[0077] The consensus group can determine the first relay transmission path to implement the uplink service request or downlink paging request. In addition, the consensus group can also achieve consistency between multiple access network devices to ensure the reliability and stability of the core network in the embodiment of the present application.

[0078] Optionally, the ad hoc network between the first access network device and the second access network device may be established in a wired manner, in a wireless manner, or in a hybrid manner of wired and wireless.

[0079] Optionally, the leader node may be selected based on a fault-tolerant algorithm, such as Paxos, Raft, ZooKeeper, or the like.

[0080] Optionally, the group identifier may be generated after the consensus group is established, may be generated each time a consensus group is established, and may be broadcast by the leader node to other nodes in the consensus group after the consensus group is initially established.

[0081] In combination with the third aspect, in certain implementations of the third aspect, the first connection message includes identification information of the terminal device, identification information of the first access network device, and path indication information, where the path indication information is used to indicate the first relay transmission path.

[0082] In combination with the third aspect, in certain implementations of the third aspect, the first connection message further includes identification information of the service request initiated by the terminal device.

[0083] In combination with the third aspect, in certain implementations of the third aspect, the method further includes: receiving a first relay service request message, the first relay service request message being used to indicate that the first access network device requests to send the first connection message via relay transmission; and sending a first relay service request response message, the first relay service request response message including path indication information, the path indication information being used to indicate the first relay transmission path.

[0084] In combination with the third aspect, in certain implementations of the third aspect, determining the first relay transmission path includes: determining the first relay transmission path based on the connection relationship between multiple access network devices included in the first consensus group, and the multiple access network devices include the first access network device and the second access network device.

[0085] In combination with the third aspect, in certain implementations of the third aspect, the method further includes: sending a connection status request message to the multiple access network devices, wherein the connection status request message is used to request determination of the connection relationship between the multiple access network devices; and receiving a connection status feedback message, wherein the connection status feedback message includes the connection relationship between the multiple access network devices.

[0086] In combination with the third aspect, in certain implementations of the third aspect, the connection status request message includes group identification information and / or connection attribute information of a first consensus group, the first consensus group includes multiple access network devices, the multiple access network devices include the first access network device and the at least one access network device, and the connection attribute information includes at least one of connection bandwidth, delay, connection type, jitter, time taken to restore the connection, and whether there is security protection.

[0087] The specific scheme description of the first connection message, the first relay service request message, the connection status request message, and the connection status feedback message can refer to the first aspect and will not be repeated here.

[0088] In a fourth aspect, a communication method is provided, which can be applied to a core network element or a component of a core network element. For simplicity, the core network element is used as an example for illustration.

[0089] The method includes: the second core network network element determines whether it is the same as the first core network network element; when the first core network network element is the same as the second core network network element, the second core network network element sends a first connection response message, and the first connection response message includes the identification information of the terminal device, the identification information of the first access network device and at least one of the path indication information, and the path indication information is used to indicate the first relay transmission path; when the first core network network element is different from the second core network network element, the second core network element sends a first connection message to the first core network network element, and the first connection message is used to indicate the first core network element to provide services for the terminal device.

[0090] In combination with the fourth aspect, in certain implementations of the fourth aspect, there is limited connectivity between the first access network device and the first core network element.

[0091] Specifically, when a terminal device initiates a service request, the first access network device needs to send a first connection message to the first core network element, which then determines whether the second core network element is the same core network element as the first. This is because each access network device connects to one core network element, and different access network devices may connect to the same core network element. In other words, the interface connection between the first access network device and the second core network element is limited, while the interface connection between the second access network device and the second core network element is complete.

[0092] If the second core network element is the same as the first core network element, the second core network element can directly provide services to the terminal device; if the second core network element is different from the first core network element, the second core network element needs to forward the received first connection message to the first core network element, and then the first core network element provides services to the terminal device.

[0093] Optionally, the second core network element can obtain the identification information of the first core network element based on the identification of the terminal device included in the first connection message, and then determine whether it is the same as the first core network element based on the identification information of the first core network element. For example, the identification information of the terminal device may be a TMSI, wherein a part of the TMSI generation algorithm is constructed based on the ID of the core network element. The ID of the core network element can then be obtained through the TMSI. For another example, the ID of the core network element can be queried from a third party, and the third party may store a mapping relationship between the TMSI of the terminal device and the ID of the core network element.

[0094] In combination with the fourth aspect, in certain implementations of the fourth aspect, the first connection message includes identification information of the terminal device, identification information of the first access network device, and path indication information, and the path indication information is used to indicate the first relay transmission path.

[0095] In combination with the fourth aspect, in certain implementations of the fourth aspect, the first connection message further includes identification information of the service request initiated by the terminal device.

[0096] In combination with the fourth aspect, in certain implementations of the fourth aspect, the method further includes: the second core network element receiving the first connection message from the second access network device.

[0097] The specific solution description of the first connection message can refer to the first aspect and will not be repeated here.

[0098] In combination with the fourth aspect, in certain implementations of the fourth aspect, the method also includes: the second core network network element determines that the terminal device accesses the first core network network element through relay transmission; the second core network network element sends a first paging request message to the second access network device, and the first paging request message is used to request to initiate paging to the terminal device.

[0099] It should be understood that when the second core network element recognizes that the terminal device accesses the core network via a relay method or the first relay transmission path mentioned above, the second core network element needs to instruct the second access network device to send a downlink paging request via the relay method used in the uplink service request process. This enables the downlink service request process initiated by the core network.

[0100] Optionally, the second core network network element can be a method for identifying whether the terminal device accesses the core network via a relay based on local records. For example, the local record includes a step in which the second core network network element needs to determine whether it is the same as the first core network network element. Then, the second core network network element can determine whether the terminal device accesses the core network via a relay based on the step in the local record. The reason is that this step is not included in the existing uplink service request process, that is, the terminal device can directly access the first core network network element. Only when the terminal device accesses the core network via a relay does the second core network network element need to use this step to determine the first core network element that provides services to the terminal device.

[0101] In other embodiments of the present application, the second core network element may determine that the terminal device accesses the core network via a relay by other means, for example, based on the path indication information recorded in the local record or the first relay transmission path. The present application does not limit the relay method for identifying the terminal device.

[0102] In combination with the fourth aspect, in certain implementations of the fourth aspect, the method also includes: the second core network network element receives a relay paging indication message from the first core network network element, and the relay paging indication message is used to instruct the terminal device to access the first core network network element via relay transmission; the second core network network element sends a first paging request message to the second access network device, and the first paging request message is used to request to initiate paging to the terminal device.

[0103] In combination with the fourth aspect, in certain implementations of the fourth aspect, the first paging request message includes identification information of the terminal device.

[0104] Optionally, the first paging request message may include identification information of the uplink service request and / or identification information of the terminal device. The identification information of the uplink service request is used to indicate the uplink service request corresponding to the downlink service request and is used to determine the first access network device for the uplink service request, and the identification information of the terminal device is used to determine to which terminal device the paging is to be initiated.

[0105] In combination with the fourth aspect, in certain implementations of the fourth aspect, before sending the first paging request message to the second access network device, the method also includes: the second core network network element determines the second access network device based on the uplink history record and the identification information of the first uplink service request, the uplink history record includes a mapping relationship between the uplink service request and the access network device, and each access network device is used to receive the corresponding uplink service request from the terminal device.

[0106] The reason why the second core network network element determines the identification information of the second access network device and the uplink service request is that: the second core network network element needs to determine the second access network device when the uplink service request is made, so as to send a paging request through the second access network device and the first relay transmission path; the second core network network element determines the identification information of the uplink service request so that the subsequent second access network device can determine the first access network device according to the identification information of the uplink service request, and then send the paging request to the first access network device.

[0107] In a fifth aspect, a communication device is provided, which includes: a transceiver unit, used to: send a first connection message through a first relay transmission path, the first connection message is used to indicate that the first core network network element provides services for the terminal device, the first relay transmission path includes a message transmission path between the first access network device and the second access network device, the second access network device is connected to the first core network network element, or the second access network device is connected to the second core network network element, and the second core network element is used to determine the first core network network element.

[0108] In combination with the fifth aspect, in certain implementations of the fifth aspect, there is limited connection between the communication device and the first core network element.

[0109] In combination with the fifth aspect, in certain implementations of the fifth aspect, the transceiver unit is further used to: receive a first service request message from the terminal device, where the first service request message is used to indicate a request to the core network element to provide service to the terminal device.

[0110] In combination with the fifth aspect, in certain implementations of the fifth aspect, the first connection message includes identification information of the terminal device, identification information of the first access network device, and path indication information, and the path indication information is used to indicate the first relay transmission path.

[0111] In combination with the fifth aspect, in certain implementations of the fifth aspect, the first connection message further includes identification information of the service request initiated by the terminal device.

[0112] In combination with the fifth aspect, in certain implementations of the fifth aspect, the transceiver unit is further used to: receive a first connection response message through the first relay transmission path, the first connection response message including identification information of the terminal device, identification information of the first access network device, and at least one of path indication information, and the path indication information is used to indicate the first relay transmission path.

[0113] In combination with the fifth aspect, in certain implementations of the fifth aspect, before the transceiver unit sends the first connection message, the transceiver unit is also used to: send a first relay service request message, which is used to indicate that the first access network device requests to send the first connection message via relay transmission; receive a first relay service request response message, which includes path indication information, and the path indication information is used to indicate the first relay transmission path.

[0114] In combination with the fifth aspect, in certain implementations of the fifth aspect, the transceiver unit is also used to: receive a connection status request message, which is used to request determination of the connection relationship between the first access network device and one or more access network devices; and send a connection status feedback message, which includes the connection relationship between the first access network device and at least one access network device.

[0115] In combination with the fifth aspect, in certain implementations of the fifth aspect, the connection status request message includes group identification information and / or connection attribute information of a first consensus group, the first consensus group includes multiple access network devices, the multiple access network devices include the first access network device and the at least one access network device, and the connection attribute information includes at least one of connection bandwidth, delay, connection type, jitter, time taken to restore the connection, and whether there is security protection.

[0116] In combination with the fifth aspect, in certain implementations of the fifth aspect, the first relay service request message includes identification information of the terminal device.

[0117] In combination with the fifth aspect, in certain implementations of the fifth aspect, the device further includes a processing unit, and before the transceiver unit sends the first connection message, the processing unit is used to: determine the first relay transmission path based on the connection relationship between multiple access network devices included in the first consensus group, and the multiple access network devices include the first access network device and the second access network device.

[0118] In combination with the fifth aspect, in certain implementations of the fifth aspect, the transceiver unit is further used to: send a connection status request message to an access network device among the multiple access network devices except the first access network device, wherein the connection status request message is used to request determination of the connection relationship between the multiple access network devices; and receive a connection status feedback message, wherein the connection status feedback message includes the connection relationship between the multiple access network devices.

[0119] In combination with the fifth aspect, in certain implementations of the fifth aspect, after the transceiver unit sends the first connection message, the transceiver unit is also used to: receive a first paging request message through the first relay transmission path, and the first paging request message is used to request to initiate paging to the terminal device.

[0120] In combination with the fifth aspect, in certain implementations of the fifth aspect, the first paging request message includes identification information of the terminal device.

[0121] In combination with the fifth aspect, in certain implementations of the fifth aspect, when the paging is successfully initiated to the terminal device, the transceiver unit is also used to: send a paging success notification message through the first relay transmission path, and the paging success notification message is used to notify the first core network network element to instruct the terminal device to perform the paging action.

[0122] In combination with the fifth aspect, in certain implementations of the fifth aspect, the second access network device is connected to the first core network network element or the second core network network element through a non-terrestrial communication network NTN.

[0123] The explanation and beneficial effects of the communication device provided in the fifth aspect can refer to the communication method shown in the first aspect and will not be repeated here.

[0124] In the sixth aspect, a communication device is provided, which includes: a transceiver unit, used to: receive a first paging request message from a first core network network element or a second core network network element, the first paging request message being used to request a first access network device to page a terminal device so that the first core network element provides services to the terminal device, the second access network device is connected to the first core network network element, or the second access network device is connected to the second core network element, and the second core network element is used to forward the first paging request message sent by the first core network network element; send the first paging request message through a first relay transmission path, the first relay transmission path including a message transmission path between the first access network device and the second access network device.

[0125] In combination with the sixth aspect, in certain implementations of the sixth aspect, there is limited connectivity between the first access network device and the first core network element.

[0126] In combination with the sixth aspect, in certain implementations of the sixth aspect, the transceiver unit is further used to: receive the first paging request message from the first core network network element or the second core network network element.

[0127] In combination with the sixth aspect, in certain implementations of the sixth aspect, the device also includes a processing unit, which is used to: determine the first access network device corresponding to the first service request message based on the log information, and the first service request message is used to indicate the request core network network element to provide service to the terminal device. The log information includes a correspondence between at least one access network device and at least one service request message, and each access network device in the at least one access network device receives a corresponding service request message from the terminal device.

[0128] In combination with the sixth aspect, in some implementations of the sixth aspect, the log information further includes path indication information, where the path indication information is used to indicate the first relay transmission path.

[0129] In combination with the sixth aspect, in certain implementations of the sixth aspect, the transceiver unit is further used to: receive the log information from an access network device in a first consensus group, the first consensus group including multiple access network devices, and the multiple access network devices including the first access network device and the second access network device.

[0130] In combination with the sixth aspect, in certain implementations of the sixth aspect, the transceiver unit is further used to: receive path indication information from an access network device in a first consensus group, the path indication information being used to indicate the first relay transmission path, the first consensus group including multiple access network devices, the multiple access network devices including the first access network device and the second access network device.

[0131] In combination with the sixth aspect, in certain implementations of the sixth aspect, the transceiver unit is further used to: send a path request message, which is used to determine the first relay transmission path; receiving path indication information from the access network device in the first consensus group includes: the second access network device receives a path request response message from the access network device in the first consensus group, and the path request response message includes the path indication information.

[0132] In combination with the sixth aspect, in certain implementations of the sixth aspect, the transceiver unit is also used to: receive a first connection message through a first relay transmission path, the first connection message being used to instruct the first core network network element to provide services for the terminal device; and send the first connection message to the first core network network element or the second core network network element.

[0133] In combination with the sixth aspect, in certain implementations of the sixth aspect, the first connection message includes identification information of the terminal device, identification information of the first access network device, and path indication information, and the path indication information is used to indicate the first relay transmission path.

[0134] In combination with the sixth aspect, in certain implementations of the sixth aspect, the first connection message further includes identification information of the service request initiated by the terminal device.

[0135] In combination with the sixth aspect, in certain implementations of the sixth aspect, the transceiver unit is further used to: receive a first relay service request message, which is used to indicate that the first access network device requests to send the first connection message via relay transmission; and send a first relay service request response message, which includes path indication information, and the path indication information is used to indicate the first relay transmission path.

[0136] In combination with the sixth aspect, in certain implementations of the sixth aspect, the first relay service request message includes identification information of the terminal device.

[0137] In combination with the sixth aspect, in certain implementations of the sixth aspect, before the transceiver unit receives the first connection message, the processing unit is also used to: determine the first relay transmission path based on the connection relationship between multiple access network devices included in the first consensus group, and the multiple access network devices include the first access network device and the second access network device.

[0138] In combination with the sixth aspect, in certain implementations of the sixth aspect, the transceiver unit is further used to: send a connection status request message to an access network device among the multiple access network devices except the second access network device, wherein the connection status request message is used to request determination of the connection relationship between the multiple access network devices; and receive a connection status feedback message, wherein the connection status feedback message includes the connection relationship between the multiple access network devices.

[0139] In combination with the sixth aspect, in certain implementations of the sixth aspect, the transceiver unit is also used to: receive a connection status request message, which is used to request determination of the connection relationship between the second access network device and one or more access network devices; and send a connection status feedback message, which includes the connection relationship between the second access network device and at least one access network device.

[0140] In combination with the sixth aspect, in certain implementations of the sixth aspect, the connection status request message includes group identification information and / or connection attribute information of a first consensus group, the first consensus group includes multiple access network devices, the multiple access network devices include the second access network device and the at least one access network device, and the connection attribute information includes at least one of connection bandwidth, delay, connection type, jitter, time taken to restore the connection, and whether there is security protection.

[0141] The explanation and beneficial effects of the communication device-related contents provided in the sixth aspect can be referred to the communication method shown in the second aspect, and will not be repeated here.

[0142] In the seventh aspect, a communication device is provided, which includes: a processing unit, used to: determine a first relay transmission path, the first relay transmission path including a message transmission path between the first access network device and the second access network device, the second access network device is connected to the first core network network element, or the second access network device is connected to the second core network network element, the second core network network element is used to determine the first core network network element; a transceiver unit, used to: send a first connection message through the first relay transmission path, the first connection message is used to instruct the first core network network element to provide services for the terminal device.

[0143] In combination with the seventh aspect, in certain implementations of the seventh aspect, there is limited connectivity between the first access network device and the first core network element.

[0144] In combination with the seventh aspect, in certain implementations of the seventh aspect, the first connection message includes identification information of the terminal device, identification information of the first access network device, and path indication information, and the path indication information is used to indicate the first relay transmission path.

[0145] In combination with the seventh aspect, in certain implementations of the seventh aspect, the first connection message also includes identification information of the service request initiated by the terminal device.

[0146] In combination with the seventh aspect, in certain implementations of the seventh aspect, the transceiver unit is further used to: receive a first relay service request message, which is used to indicate that the first access network device requests to send the first connection message via relay transmission; and send a first relay service request response message, which includes path indication information, and the path indication information is used to indicate the first relay transmission path.

[0147] In combination with the seventh aspect, in certain implementations of the seventh aspect, the processing unit is specifically used to: determine the first relay transmission path based on the connection relationship between multiple access network devices included in the first consensus group, and the multiple access network devices include the first access network device and the second access network device.

[0148] In combination with the seventh aspect, in certain implementations of the seventh aspect, the transceiver unit is also used to: send a connection status request message to the multiple access network devices, wherein the connection status request message is used to request determination of the connection relationship between the multiple access network devices; and receive a connection status feedback message, wherein the connection status feedback message includes the connection relationship between the multiple access network devices.

[0149] In combination with the seventh aspect, in certain implementations of the seventh aspect, the connection status request message includes group identification information and / or connection attribute information of a first consensus group, the first consensus group includes multiple access network devices, the multiple access network devices include the first access network device and the at least one access network device, and the connection attribute information includes at least one of connection bandwidth, delay, connection type, jitter, time taken to restore the connection, and whether there is security protection.

[0150] The explanation and beneficial effects of the communication device-related contents provided in the seventh aspect can refer to the communication method shown in the third aspect and will not be repeated here.

[0151] In the eighth aspect, a communication device is provided, which includes: a processing unit, used to: determine whether it is the same as the first core network network element; a transceiver unit, used to: when the first core network network element is the same as the second core network element, send a first connection response message, the first connection response message including the identification information of the terminal device, the identification information of the first access network device and at least one of the path indication information, the path indication information is used to indicate the first relay transmission path; when the first core network network element is different from the second core network element, send a first connection message to the first core network network element, the first connection message is used to indicate that the first core network element provides services for the terminal device.

[0152] In combination with the eighth aspect, in certain implementations of the eighth aspect, there is limited connectivity between the first access network device and the first core network element.

[0153] In combination with the eighth aspect, in certain implementations of the eighth aspect, the first connection message includes identification information of the terminal device, identification information of the first access network device, and path indication information, and the path indication information is used to indicate the first relay transmission path.

[0154] In combination with the eighth aspect, in certain implementations of the eighth aspect, the first connection message also includes identification information of the service request initiated by the terminal device.

[0155] In combination with the eighth aspect, in certain implementations of the eighth aspect, the transceiver unit is further used to: receive the first connection message from the second access network device.

[0156] In combination with the eighth aspect, in certain implementations of the eighth aspect, the processing unit is also used to: determine that the terminal device accesses the first core network network element via relay transmission; the transceiver unit is also used to: the second core network network element sends a first paging request message to the second access network device, and the first paging request message is used to request to initiate paging to the terminal device.

[0157] In combination with the eighth aspect, in certain implementations of the eighth aspect, the transceiver unit is further used to: receive a relay paging indication message from the first core network network element, the relay paging indication message being used to instruct the terminal device to access the first core network network element via relay transmission; and send a first paging request message to the second access network device, the first paging request message being used to request paging to the terminal device.

[0158] In combination with the eighth aspect, in certain implementations of the eighth aspect, the first paging request message includes identification information of the terminal device.

[0159] In combination with the eighth aspect, in certain implementations of the eighth aspect, before sending the first paging request message to the second access network device, the processing unit is also used to: the second core network network element determines the second access network device based on the uplink history record and the identification information of the first uplink service request, the uplink history record includes a mapping relationship between the uplink service request and the access network device, and each access network device is used to receive the corresponding uplink service request from the terminal device.

[0160] The explanation and beneficial effects of the communication device-related contents provided in the eighth aspect can be referred to the communication method shown in the fourth aspect, and will not be repeated here.

[0161] In a ninth aspect, a communication device is provided, comprising a processor, wherein the processor is configured to enable the communication device to execute the method described in the first aspect and any possible method described in the first aspect by executing a computer program or instruction or through a logic circuit.

[0162] In a possible implementation, the communication device further includes a memory for storing the computer program or instruction.

[0163] In a possible implementation, the communication device further includes a communication interface, which is used to input and / or output signals.

[0164] In a tenth aspect, a communication device is provided, comprising a processor, wherein the processor is configured to enable the communication device to execute the method described in the second aspect and any possible method described in the second aspect by executing a computer program or instruction or through a logic circuit.

[0165] In a possible implementation, the communication device further includes a memory for storing the computer program or instruction.

[0166] In a possible implementation, the communication device further includes a communication interface, which is used to input and / or output signals.

[0167] In an eleventh aspect, a communication device is provided, comprising a processor, wherein the processor is configured to enable the communication device to execute the method described in the third aspect and any possible method described in the third aspect by executing a computer program or instruction or through a logic circuit.

[0168] In a possible implementation, the communication device further includes a memory for storing the computer program or instruction.

[0169] In a possible implementation, the communication device further includes a communication interface, which is used to input and / or output signals.

[0170] In the twelfth aspect, a communication device is provided, comprising a processor, wherein the processor is configured to enable the communication device to execute the method described in the fourth aspect and any possible method described in the fourth aspect by executing a computer program or instruction or through a logic circuit.

[0171] In a possible implementation, the communication device further includes a memory for storing the computer program or instruction.

[0172] In a possible implementation, the communication device further includes a communication interface, which is used to input and / or output signals.

[0173] In the thirteenth aspect, a communication device is provided, comprising a logic circuit and an input / output interface, the input / output interface being used to input and / or output signals, the logic circuit being used to execute the method described in the first aspect and any possibility of the first aspect; or, the logic circuit being used to execute the method described in the second aspect and any possibility of the second aspect; the logic circuit being used to execute the method described in the third aspect and any possibility of the third aspect; the logic circuit being used to execute the method described in the fourth aspect and any possibility of the fourth aspect.

[0174] In the fourteenth aspect, a computer-readable storage medium is provided, on which a computer program or instruction is stored. When the computer program or the instruction is run on a computer, the method described in the first aspect and any possibility of the first aspect is executed; or, the method described in the second aspect and any possibility of the second aspect is executed; the method described in the third aspect and any possibility of the third aspect is executed; and the method described in the fourth aspect and any possibility of the fourth aspect is executed.

[0175] In the fifteenth aspect, a computer program product is provided, comprising instructions, which, when executed on a computer, cause the method described in the first aspect and any possibility of the first aspect to be executed; or, cause the method described in the second aspect and any possibility of the second aspect to be executed; or, cause the method described in the third aspect and any possibility of the third aspect to be executed; or, cause the method described in the fourth aspect and any possibility of the fourth aspect to be executed.

[0176] In the sixteenth aspect, a communication system is provided, which includes the communication device as described in the fifth to eighth aspects, or includes the communication device as described in the ninth to twelfth aspects.

[0177] For the description of the beneficial effects of the fifth to sixteenth aspects, reference can be made to the description of the first to fourth aspects. BRIEF DESCRIPTION OF THE DRAWINGS

[0178] FIG1 is a schematic diagram of a network architecture provided in an embodiment of the present application.

[0179] FIG2 is a schematic diagram of a fault-tolerant consensus algorithm provided in an embodiment of the present application.

[0180] FIG3 is a schematic flowchart of an existing uplink service request provided in an embodiment of the present application.

[0181] FIG4 is a schematic flowchart of an existing downlink service request provided in an embodiment of the present application.

[0182] FIG5 is a schematic flowchart of a communication method provided in an embodiment of the present application.

[0183] FIG6 is a schematic flowchart of another communication method provided in an embodiment of the present application.

[0184] FIG7 is a schematic flowchart of another communication method provided in an embodiment of the present application.

[0185] FIG8 is a schematic flowchart of another communication method provided in an embodiment of the present application.

[0186] FIG9 is a schematic flowchart of another communication method provided in an embodiment of the present application.

[0187] FIG10 is a schematic flowchart of another communication method provided in an embodiment of the present application.

[0188] FIG11 is a schematic flowchart of another communication method provided in an embodiment of the present application.

[0189] FIG12 is a schematic flowchart of another communication method provided in an embodiment of the present application.

[0190] FIG13 is a schematic flowchart of another communication method provided in an embodiment of the present application.

[0191] FIG14 is a schematic flowchart of another communication method provided in an embodiment of the present application.

[0192] FIG15 is a schematic flowchart of another communication method provided in an embodiment of the present application.

[0193] FIG16 is a schematic flowchart of another communication method provided in an embodiment of the present application.

[0194] Figure 17 is a schematic block diagram of a communication device provided in an embodiment of the present application.

[0195] FIG18 is a schematic block diagram of another communication device provided in an embodiment of the present application.

[0196] Figure 19 is a schematic block diagram of another communication device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0197] The technical solution in this application will be described below with reference to the accompanying drawings.

[0198] To make the objectives, technical solutions, and advantages of this application more clear, the present application will be further described in detail below with reference to the accompanying drawings. The specific operating methods in the method embodiments can also be applied to the device embodiments or system embodiments. In the description of this application, unless otherwise specified, the meaning of "multiple" is two or more.

[0199] In the various embodiments of the present application, unless otherwise specified or there is a logical conflict, the terms and / or descriptions between different embodiments are consistent and can be referenced by each other. The technical features in different embodiments can be combined to form new embodiments according to their inherent logical relationships.

[0200] It is understood that the various numbers used in this application are merely for ease of description and are not intended to limit the scope of this application. The order of execution of the above-mentioned processes does not necessarily imply a specific order of execution. The order of execution of each process should be determined by its function and inherent logic.

[0201] The terms "first," "second," "third," "fourth," and various other terminology designations, if any, in the specification and claims of this application and in the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a particular order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate so that the embodiments described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "including" and "having," and any variations thereof, are intended to cover non-exclusive inclusions, e.g., a process, method, system, product, or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such process, method, product, or apparatus.

[0202] It is understood that in this application, "used to indicate" can be understood as "enabling", and "enabling" can include direct enabling and indirect enabling. When describing that a certain information is used to enable A, it can include that the information directly enables A or indirectly enables A, and it does not mean that the information necessarily carries A. The terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices. "Pre-configuration" may include pre-definition, such as protocol definition. Among them, "pre-definition" can be implemented by pre-saving corresponding codes, tables or other methods that can be used to indicate relevant information in a device (for example, including various network elements). This application does not limit its specific implementation method. The "saving" involved in the embodiments of the present application may refer to saving in one or more memories. The one or more memories may be separate settings or integrated in an encoder or decoder, a processor, or a communication device. The one or more memories may also be partially set separately, and partially integrated into a decoder, a processor, or a communication device. The type of memory may be any form of storage medium, and this application is not limited to this. The "protocol" involved in the embodiments of the present application may refer to a standard protocol in the field of communications, for example, it may include 4G / 5G protocols, new radio (NR) protocols, and related protocols used in future communication systems, and this application is not limited to this. The dotted boxes in the method flow chart in the accompanying drawings of the present application specification represent optional steps.

[0203] The network architecture and business scenarios described in the embodiments of the present application are intended to more clearly illustrate the technical solutions of the embodiments of the present application, and do not constitute a limitation on the technical solutions provided in the embodiments of the present application. Ordinary technicians in this field will know that with the evolution of network architecture and the emergence of new business scenarios, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

[0204] The technical solutions provided in this application can be applied to various communication systems, such as: fifth generation (5G) or new radio (NR) systems, long term evolution (LTE) systems, LTE frequency division duplex (FDD) systems, LTE time division duplex (TDD) systems, etc. The technical solutions provided in this application can also be applied to future communication systems, such as the sixth generation mobile communication system. The technical solutions provided in this application can also be applied to device to device (D2D) communication, vehicle-to-everything (V2X) communication, machine to machine (M2M) communication, machine type communication (MTC), and Internet of Things (IoT) communication systems or other communication systems.

[0205] In a communication system, the part operated by the operator may be referred to as a public land mobile network (PLMN) (also referred to as an operator network, etc.). PLMN is a network established and operated by the government or an operator approved by it for the purpose of providing land mobile communication services to the public. It is mainly a public network in which mobile network operators (MNOs) provide mobile broadband access services to users. The PLMN described in this application may specifically be a network that meets the requirements of the 3rd Generation Partnership Project (3GPP) standards, referred to as a 3GPP network. 3GPP networks generally include but are not limited to fifth-generation mobile communication (5th-generation, 5G) networks (referred to as 5G networks), fourth-generation mobile communication (4th-generation, 4G) networks (referred to as 4G networks), and other future communication systems such as 6G networks.

[0206] Figure 1 is a schematic diagram of a network architecture of an embodiment of the present application. For convenience, the 5G network architecture is used as an example. The network architecture may include three parts: a terminal device (also referred to as user equipment (UE)), a PLMN, and a data network (DN). The PLMN may include, but is not limited to: a network exposure function (NEF), a policy control function (PCF), a unified data management function (UDM), an authentication server function (AUSF), an access and mobility management function (AMF) network element, a session management function (SMF), a user plane function (UPF), an application function (AF), a network slice specific authentication and authorization function (NSSAAF), an authentication and key management for application anchor function (AAnF), a (radio) access network (R)AN), etc. In the above PLMN, the part other than the (wireless) access network part can be referred to as the core network (CN) part. By way of example, the following provides an exemplary description of each network or function and a terminal device using the network.

[0207] 1. Terminal equipment

[0208] The terminal device in the embodiments of the present application can be: user equipment (UE), mobile station (MS), mobile terminal (MT), access terminal, user unit, user station, mobile station, mobile station, remote station, remote terminal, mobile device, user terminal, terminal, wireless communication equipment, user agent or user device, etc.

[0209] The terminal device may be a device that provides voice / data connectivity to users, such as a handheld device or vehicle-mounted device with wireless connection function. Examples of terminal devices include: mobile phones, tablet computers, laptop computers, 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 or autopilot, wireless terminals in remote medical surgery, wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in smart cities, wireless terminals in smart homes, cellular phones, cordless phones, session initiation protocol (SIP) phones, wireless local loop (WLL) stations, personal digital assistants (PDAs), handheld devices with wireless communication capabilities, computing devices or other processing devices connected to wireless modems, vehicle-mounted devices, wearable devices, terminal devices in future 5G networks or future evolved public land mobile communication networks (PLMNs). The terminal equipment in the network (PLMN), etc., is not limited to this in the embodiments of the present application.

[0210] As an example and not a limitation, in the embodiment of the present application, the terminal device may also be a wearable device. Wearable devices may also be called wearable smart devices, which are a general term for wearable devices that are intelligently designed and developed using wearable technology for daily wear, such as glasses, gloves, watches, clothing, and shoes. A wearable device is a portable device that is worn directly on the body or integrated into the user's clothes or accessories. Wearable devices are not only hardware devices, but also achieve powerful functions through software support, data interaction, and cloud interaction. Broadly speaking, wearable smart devices include devices that are fully functional, large in size, and can achieve complete or partial functions without relying on smartphones, such as smart watches or smart glasses, as well as devices that only focus on a certain type of application function and need to be used in conjunction with other devices such as smartphones, such as various types of smart bracelets and smart jewelry for vital sign monitoring. In addition, in the embodiment of the present application, the terminal device may also be a terminal device in an Internet of Things (IoT) system.

[0211] 2. Access Network (AN)

[0212] The access network is a subnetwork of the PLMN and is the implementation system between the service nodes (or network functions) in the PLMN and the terminal device 110. To access the PLMN, the terminal device first passes through the (R)AN and then connects to the service node in the PLMN through the (R)AN. The (R)AN in the embodiments of the present application can refer to the access network itself or the access network device, and no distinction is made here. The access network device is a device that provides wireless communication functions for the terminal device 110, and can also be called an access device, (R)AN device, or network device. The access network equipment includes but is not limited to: the next generation node basestation (gNB) in the 5G system, the evolved node B (eNB) in the LTE system, the radio network controller (RNC), the node B (NB), the base station controller (BSC), the base transceiver station (BTS), the home evolved nodeB (or home node B, HNB), the base band unit (BBU), the transmission and receiving point (TRP), the transmitting point (TP), the small base station equipment (pico), the mobile switching center, or the network equipment in the future network, etc. It is understandable that the present application does not limit the specific type of access network equipment. In systems using different wireless access technologies, the names of devices with access network equipment functions may be different.

[0213] Optionally, in some deployments of access devices, the access device may include a centralized unit (CU) and a distributed unit (DU). In other deployments of access devices, the CU may be further divided into a CU-control plane (CP) and a CU-user plane (UP). In still other deployments of access devices, the access device may also be an open radio access network (ORAN) architecture. This application does not limit the specific deployment method of the access device.

[0214] 3. Access and Mobility Management Function (AMF) network element

[0215] The access and mobility management function network element can be used for mobility management and access management, etc., and can be used to implement other functions of the mobility management entity (MME) in addition to session management, such as legal detection or access authorization. In addition, it is also used to transmit user policies between terminal devices and policy control function (PCF) network elements. In the embodiment of the present application, the access and mobility management function network element can be used to implement the functions of the access and mobility management network element.

[0216] 4. Session Management Function (SMF) Network Element

[0217] The session management function network element can be used for session management, allocation and management of Internet Protocol (IP) addresses for terminal devices, selection and management of user plane function (UPF) network elements, termination points of policy control and charging function interfaces, and downlink data notification. In the embodiment of the present application, the session management function network element can be used to implement the functions of the session management network element.

[0218] 5. User Plane Function (UPF) Network Element

[0219] The user plane function network element can be used for packet routing and forwarding, or quality of service (QoS) parameter processing of user plane data. User data can be accessed to the data network (DN) through this network element. In the embodiment of the present application, the user plane function network element can be used to implement the functions of the user plane network element. For example, when establishing a session on different user plane function network elements, the service experience of the terminal device will also be different. Therefore, the above-mentioned session management function network element is required to select an appropriate user plane function network element for the session of the terminal device.

[0220] 6. Policy Control Function (PCF) Network Element

[0221] The policy control network element is a unified policy framework used to guide network behavior, and provides policy rule information to control plane functional network elements (such as access and mobility management function network element, session management function network element, etc.). It is mainly responsible for policy control functions such as billing, QoS bandwidth guarantee and mobility management, and terminal device policy decision-making at the session and service flow level. The policy control network element can have the capabilities of both the access and mobility management policy control network element (AM PCF) and the session management policy control network element (SM PCF). Logically, the access and mobility management policy control network element and the session management policy control network element can be understood as different network elements with different capabilities. In actual deployment scenarios, the access and mobility management policy control network element and the session management policy control network element can be the same policy control network element entity, that is, deployed separately, or they can be two different policy control network element entities, that is, deployed in one.

[0222] For example, the access and mobility management policy control network element is directly connected to the access and mobility management function network element, and the access and mobility management policy control network element provides mobility and access selection-related policies for terminal devices to the access and mobility management network element management function network element. Among them, mobility policies include, for example, service area restriction management, radio access technology frequency selection priority (RFSP) index management, and session management function network element selection management. Among them, access selection-related policies for terminal devices include access network discovery and selection policy (ANDSP) and route selection policy (URSP) for terminal devices. For another example, the session management policy control network element is directly connected to the session management function network element, and provides protocol data unit (PDU) session-related policies to the session management function network element. Among them, PDU session-related policies include, for example, gating policies, charging policies, QoS control policies, usage monitoring control policies, etc.

[0223] It should be understood that for roaming scenarios, the policy control network element of the visited location can logically include the access and mobility management policy control network element of the visited location and the session management policy control network element of the visited location; the policy control network of the home location can logically include the access and mobility management policy control network element of the home location and the session management policy control network element of the home location. In actual deployment, the access and mobility management policy control network element of the visited location and the session management policy control network element of the visited location can be the same policy control network element entity of the visited location, or they can be two different policy control network element entities of the visited location. Similarly, in actual deployment, the access and mobility management policy control network element of the home location and the session management policy control network element of the home location can be the same policy control network element entity of the home location, or they can be two different policy control network element entities of the home location.

[0224] 7. Network Exposure Function (NEF) Network Element

[0225] The network capability exposure function network element is used to open the services and network capability information (such as terminal location) provided by the 3GPP network function to the outside world.

[0226] 8. Unified Data Management (UDM) Network Element

[0227] The unified data management network element can be used for unified data management, supporting authentication trust state processing in the 3GPP authentication and key negotiation mechanism, user identity processing, access authorization, registration and mobility management, contract management, short message management, etc.

[0228] 9. AKMA Anchor Function (AAnF) Network Element

[0229] AAnF will interact with AUSF to request the AKMA root key Kakma, and will be responsible for generating the key Kaf used by AF and the validity period of Kaf.

[0230] 10. Authentication Server Function (AUSF) Network Element

[0231] The authentication server function network element is a control plane function provided by the operator and is usually used for level 1 authentication, that is, authentication between the terminal device (subscriber) and the PLMN. In the AKMA scenario, the authentication server function network element can generate the AKMA root key KAKMA for the AAnF.

[0232] 11. Application Function (AF) Network Element

[0233] The application function network element primarily provides services by interacting with other NFs in the CN. For example, it provides roaming UEs with information on selecting a visited network (visiting PLMN or VPLMN), directs data flow routing, and provides access to the NEF. The AF can be deployed by the operator within the PLMN or outside the operator network. If the AF is within the PLMN, it can interact directly with the PCF. If the AF is outside the PLMN, the NEF acts as an intermediary to forward the interactions between the AF and the PCF. In the AKMA scenario, the AF can interact with the AAnF to obtain the KAF and the KAF validity period.

[0234] 12. Network Slice Authentication and Authorization Function (NSSAAF) network element

[0235] The network slice authentication and authorization function network element is a control plane network function provided by the PLMN, which is used to support slice authentication between the terminal and the DN.

[0236] 13. Data Network (DN)

[0237] A data network, also known as a packet data network (PDN), is typically deployed outside of a PLMN, such as a third-party network (of course, a DN may also be deployed within a PLMN, but this is not a limitation here). For example, a PLMN can access multiple data networks (DNs), on which various services can be deployed, providing data and / or voice services to UEs. For example, a DN can be the private network of a smart factory. Sensors installed in the factory workshop can be UEs. A control server for the sensors is deployed within the DN, and the control server can provide services to the sensors. The sensors can communicate with the control server, receive instructions from the control server, and transmit collected sensor data to the control server according to the instructions. For another example, a DN can be a company's internal office network. The company's employees' mobile phones or computers can be UEs, allowing them to access information and data resources on the company's internal office network. UEs can establish connections with the PLMN through interfaces provided by the PLMN (such as the N1 interface in Figure 1) and use the data and / or voice services provided by the PLMN. UEs can also access DNs through the PLMN and use operator services and / or third-party services deployed on the DN. The third party may be a service provider other than the PLMN and the terminal device 110, and may provide the UE with other data and / or voice services. The specific form of the third party may be determined according to the actual application scenario and is not limited here.

[0238] In Figure 1, Nnef, Npcf, Nudm, Nnssf, Nausf, Namf, Nsmf, Nnssaaf, Naf, N1, N2, N3, N4, and N6 are interface sequence numbers. For example, the meanings of the above interface sequence numbers can be found in the meanings defined in the 3GPP standard protocol, and this application does not limit the meanings of the above interface sequence numbers.

[0239] For example, the N1 interface can be a signaling plane interface between the UE and the AMF. It is a logical interface and there is no physical interface. In addition, the N1 interface is implemented based on the N2 interface signaling. The N2 interface is the signaling plane interface between the (R)AN and the AMF. It is similar to the s1-mme interface in 4G. The N3 interface is the interface between the 5G(R)AN (Radio Access Network) and the UPF (User Plane Function), and is mainly used to transmit uplink and downlink user plane data between the 5G(R)AN and the UPF. The Xn interface is used for interconnection between NG-RAN nodes. The Xn interface is an open interface. The Xn interface supports the exchange of signaling messages between NG-RAN nodes and can forward protocol data packets to the corresponding nodes. From a logical perspective, the Xn interface is a p2p interface between NG-RAN nodes. This P2P logical interface should be able to work even if there is no direct physical link between the two NG-RAN nodes.

[0240] It should be noted that Figure 1 only provides an exemplary illustration of the terminal device as UE, and the interface name between the various network functions in Figure 1 is only an example. In a specific implementation, the interface name of the system architecture may also be other names, and this application does not limit this.

[0241] The network architecture diagram shown in Figure 1 can be understood as a service-based architecture. In this service-based architecture, the PLMN can combine some or all network functions in an orderly manner according to specific scenario requirements, achieving customized network capabilities and services. This allows for the deployment of dedicated networks for different services, a process known as network slicing. Network slicing technology enables operators to respond to customer needs more flexibly and quickly, supporting flexible allocation of network resources.

[0242] It should be understood that the above-mentioned network architecture applied to the embodiment of the present application is only an example of the network architecture described from the perspective of traditional point-to-point architecture and service-oriented architecture. The network architecture applicable to the embodiment of the present application is not limited to this. Any network architecture that can realize the functions of the above-mentioned network elements is applicable to the embodiment of the present application.

[0243] It should be understood that the interface names between the various network elements in Figure 1 are only examples. In specific implementations, the interface names may be other names, and this application does not specifically limit this. In addition, the names of the messages (or signaling) transmitted between the various network elements are only examples and do not constitute any limitation on the functions of the messages themselves.

[0244] It is understood that the above-mentioned network element or function can be a network element in a hardware device, a software function running on dedicated hardware, or a virtualized function instantiated on a platform (e.g., a cloud platform). Optionally, the above-mentioned network element or function can be implemented by a single device, or by multiple devices, or as a functional module within a single device, and this is not specifically limited in the embodiments of the present application.

[0245] It should also be understood that in the communication system shown in FIG1 , the functions of each network element are merely exemplary, and not all functions of each network element are required when applied in the embodiments of the present application.

[0246] In addition, the naming of each network element (such as PCF, AMF, etc.) included in Figure 1 is only a name, and the name does not limit the function of the network element itself. In 5G networks and other future networks, the above-mentioned network elements may also have other names, and the embodiments of this application do not specifically limit this. For example, in a 6G network, some or all of the above-mentioned network elements may use the terminology in 5G, or may be named otherwise, etc., which are uniformly explained here and will not be repeated below.

[0247] It should also be noted that the communication between the various network elements of the control plane function in Figure 1 is described using a non-service interface as an example, but this does not limit the scope of protection of the embodiments of the present application. Those skilled in the art will understand that the various network elements of the control plane function in Figure 1 can also communicate through a service interface. For example, the service interface provided by AMF to the outside world may be Namf; the service interface provided by SMF may be Nsmf; the service interface provided by AF may be Naf; the service interface provided by PCF to the outside world may be Npcf, and so on.

[0248] To facilitate understanding of the solutions provided by the embodiments of the present application, some of the terms or concepts involved in the present application are exemplified below.

[0249] 1. Cyber ​​resilience

[0250] Cyber ​​resilience refers to a system's ability to maintain its original functionality despite adverse cyber events. Cyber ​​resilience is crucial for information systems, critical infrastructure, business processes, organizations, societies, and nations. Adverse cyber events are those that impact the availability, data integrity, and confidentiality of cyber information systems and their information. These events can be intentional (e.g., cyber attacks) or unintended (e.g., software update failures) and can be caused by human factors, natural factors, or a combination of both.

[0251] Cyber ​​resilience is somewhat different from cyber security. Cyber ​​security is about protecting systems, networks, and data from cybercrime. Cyber ​​resilience, on the other hand, is about protecting systems and networks from threats, ensuring they can continue to operate normally.

[0252] 2. Fault Tolerance Algorithm

[0253] A fault-tolerant consensus algorithm is a consensus algorithm used in distributed systems. It aims to ensure that all nodes (or groups of nodes) can reach a consensus even in the event of failures or network partitions. The main function of a fault-tolerant consensus algorithm is to ensure data consistency in a distributed system and to maintain service availability even in the event of node failures or network partitions.

[0254] Figure 2 shows a schematic diagram of a fault-tolerant algorithm applicable to an embodiment of the present application. As shown in Figure 2, the network includes a service node and nodes A to E that provide services to the service node. In the event of a network partition or failure of some nodes in the network shown in Figure 2, nodes A to E can decide, through voting or other means, that node B becomes the leader node and leads other nodes to reach a consensus, or in other words, ensure the consistency of the data of nodes A to E and provide services to the service node.

[0255] Common fault-tolerant consensus algorithms include Paxos, Raft, and ZooKeeper. These algorithms typically use voting to determine which node becomes the leader in the event of a failure or network partition, leading other nodes to consensus. Furthermore, fault-tolerant consensus algorithms can also be used to implement leader election, distributed transactions, and load balancing in distributed systems. In short, fault-tolerant consensus algorithms are crucial in distributed systems, ensuring data consistency and improving system reliability and stability.

[0256] 3. Distributed ledger technology (DLT)

[0257] A distributed ledger is a database that is distributed across multiple nodes or computing devices, each of which can replicate and store a copy of the ledger, and each node can independently update it.

[0258] The groundbreaking feature of distributed ledger technology is that the ledger is not maintained by any central authority. Instead, updates to the ledger are independently constructed and recorded by each node. Nodes can vote on these updates to ensure they align with majority opinion. This voting process, known as consensus, is automatically reached through algorithms. Once consensus is reached, the distributed ledger automatically updates, with the latest agreed-upon version of the ledger stored on each node. Distributed ledger technology significantly reduces the cost of trust, thereby alleviating reliance on banks, governments, lawyers, notaries, and other institutions. At the same time, it can address issues such as consumer protection, financial integrity, and transaction speed.

[0259] 4. Blockchain technology

[0260] Blockchain is a form of distributed ledger technology, and not all distributed ledgers use a chain of blocks to provide secure and efficient distributed consensus.

[0261] All blocks are distributed across a peer-to-peer network. Because it's a distributed ledger, it can exist without server management, and its data quality is maintained through database replication and computational validation. However, the blockchain's append-only structure distinguishes it from other types of distributed ledgers. Data on a blockchain is grouped into blocks, which are linked to each other and secured using cryptographic techniques. A blockchain is essentially a continuously growing list of records, and its structure only allows data to be appended to the database, making it impossible to alter or delete previously entered data. Therefore, blockchain technology is well-suited for recording events, managing records, processing transactions, tracking assets, and voting. Every blockchain is a distributed ledger, but not every distributed ledger is a blockchain. Both require decentralization and consensus among nodes.

[0262] 5. Multilateral Trust Model and Communication-Coupled DLT

[0263] 6G introduces a multilateral trust model to meet the needs of diverse trust scenarios. The consensus model is crucial within this model because it utilizes a distributed architecture and shares responsibility across multiple parties. The aforementioned "coupled blockchain" is a key element in integrating DLT into future communication networks. It refers to a blockchain that interacts with the communication network during protocol flows, including offline connections and online verification. This enables blockchain-based identity verification services, ensuring the foundation for trust and traceability.

[0264] 6. Service Request

[0265] At present, user equipment (UE) or 5G core network (5th generation core network, 5GC) in signaling idle state (CM-IDLE) can use the service request process to request to establish a secure connection to the core network element such as access and mobility management function (AMF). In the service request process, when the UE and the core network element such as AMF are in signaling idle state (CM-IDLE) or signaling connected state (CM-CONNECTED), the user plane connection is activated for the established PDU (protocol data unit) session through the service request. For example, after establishing a signaling connection with the AMF, the UE or the core network can send a signaling message to the session management function (SMF) through the AMF to establish a PDU session.

[0266] The service request process is used by the UE to request activation of the user plane connection of the PDU session and respond to the NAS notification message from the AMF. When the user plane connection of a PDU session is activated, the application server layer in the terminal notifies it to the non-access stratum (NAS). The following takes the 5G system as an example to introduce the specific process of service request at this stage. Among them, Figure 3 shows a schematic flow chart of a UE triggering an uplink service request applicable to an embodiment of the present application, and Figure 4 shows a schematic flow chart of a core network triggering a downlink service request applicable to an embodiment of the present application.

[0267] First, the process of UE triggering uplink service request is introduced based on Figure 3. The service request process shown in Figure 3 includes steps 1 to 4.

[0268] Step 1: The UE sends an AN message to the RAN. The AN message includes AN parameters, service request (including activated PDU session, allocated PDU session, encryption parameters, PDU session status, 5G S-temporary mobile subscriber identity (5G-S-TMSI), NAS message, Exempt Indication, etc.).

[0269] Step 2: RAN sends an N2message to AMF, where the N2message may include N2 parameters and the service request in step 1. If the AMF cannot process the service request, it will reject it.

[0270] If 5G access network equipment is used, the N2 parameters include 5G-S-TMSI, PLMN ID (or PLMN ID and network identifier (NID), location information, establishment cause, and UE context request message.

[0271] When the UE is currently in the idle state, the NG-RAN obtains the 5G-S-TMSI through the radio resource control (RRC) process, and the NG-RAN selects the AMF through the 5G-S-TMSI, where the location information of the AMF is associated with the cell where the UE is located.

[0272] Step 3: The AMF sends an N2 request to the RAN, where the N2 request may include a security context and a mobility restriction list (list of recommended cells / Tas / NG-RAN node identifiers).

[0273] If the service request is not sent with integrity protection or the integrity protection verification fails, the AMF shall reject the service request.

[0274] The technical solutions related to the uplink service request of this application mainly focus on steps 1 to 3 above.

[0275] Step 4: AMF sends a PDU session security context update request message (Nsmf_PDUSession_UpdateSMContext Request) to SMF, which includes PDU session ID(s), operation type, UE location information, access type, radio access technology type, UE presence in the local area data network (LADN) service area, etc.

[0276] Next, the process of triggering a downlink service request in the core network is described based on Figure 4. The service request process shown in Figure 4 includes steps 1 to 4.

[0277] When the network side needs to send a signal to the UE (for example, N1 signaling is sent to the UE, such as when pushing mobile applications (such as video, WeChat), the user plane connection of the PDU session is activated to transmit mobile user data), the process shown in Figure 4 will be used. When the process is sent by SMSF, PCF, LMF, GMLC, NEF or UDM, the SMF in Figure 4 should be replaced by the corresponding NF. If the UE is in the CM-IDLE state and asynchronous type communication is not activated, the network will send a paging request to the (R)AN / UE. The paging request triggers the UE-triggered service request process. If asynchronous type communication is activated, when the UE enters the CM-CONNECTED state, the network stores the received message and forwards the message to the RAN / UE (that is, synchronizes the context with the (R)AN / UE).

[0278] If the UE is in CM-IDLE state in non-3GPP access and the UE is registered in the PLMN through both 3GPP and non-3GPP access, the network side shall initiate the network-triggered service request procedure through 3GPP access.

[0279] If the UE is in CM-IDLE state in 3GPP access and in CM-CONNECTED state in non-3GPP access, and if the UE is registered through 3GPP and non-3GPP access in the same PLMN, the network side performs the service request procedure for 3GPP access through non-3GPP access.

[0280] Step 1: DN sends downlink data to UPF.

[0281] When the UPF receives the downlink data of the PDU session, it can buffer the downlink data (steps 2a and 2b) or forward the downlink data to the SMF (step 2c) according to the instructions of the SMF when the AN tunnel information is not stored in the UPF of the PDU session.

[0282] Step 2: UPF sends downlink data or data notification to SMF.

[0283] The data notification sent from the UPF to the SMF includes: N4 session ID, downlink data packet identification information (information to identify the QoS Flow for the DL data packet) and differentiated services code point (DSCP).

[0284] For any QoS flow, when the first downlink data packet arrives, if the SMF has not previously notified the UPF not to send data notification to the SMF, the UPF will send a data notification message to the SMF.

[0285] If the UPF receives a downlink data packet of another QoS flow in the same PDU session, the UPF will send another data notification message to the SMF.

[0286] If the UPF supports the paging policy differentiation function and the PDU session type is IP, the UPF shall also include the DSCP value in the IP header of the downlink packet and the information identifying the QoS flow of the DL packet in the TOS (IPv4) / TC (IPv6).

[0287] Optionally, step 2 may further include the SMF sending a data notification ack to the UPF. The UPF sends downlink data to the SMF. If the SMF instructs the UPF to do so, the UPF forwards the downlink data packet to the SMF (i.e., the SMF buffers the data packet).

[0288] If the SMF supports the paging policy differentiation function and the PDU session type is IP, the SMF determines the paging policy indication packet based on the DSCP value in the TOS (IPv4) / TC (IPv6) value in the received downlink IP header, and identifies the corresponding QoS flow from the QFI of the received DL packet.

[0289] In step 3a, SMF sends an N1N2 resource transfer request message (Namf_Communication_N1N2 Message Transfer) to AMF.

[0290] Among them, the N1N2 resource transfer request message includes the user permanent identifier (SUPI), PDU session ID, N1SM container (SM message), N2SM information (including QFI(s), QoS profile, CN N3 tunnel information, S-NSSAI), N2SM information valid area, address resolution protocol (ARP), paging policy indicator (paging policy indicator), 5G service quality parameters (5QI), and N1N2Transfer Failure notification target address.

[0291] In step 3b, AMF sends a N1N2 resource transfer request response message (Namf_Communication_N1N2 Message Transfer Response) to SMF.

[0292] If the UE is in CM-IDLE state at the AMF and the AMF is able to page the UE, the AMF immediately sends a Namf_Communication_N1N2MessageTransfer response to the SMF with the cause "Attempting to reach UE" indicating to the SMF that the N2SM is available once the UE is reachable. The AMF may ignore the information provided in step 3a and may ask the SMF to provide the N2SM information again.

[0293] Step 4a, UP reactivation (Connected).

[0294] If the UE is in the CM-CONNECTED state in association with the PDU Session ID received from the SMF in step 3a, steps 12 to 22 of the UE-triggered service request procedure are performed for this PDU Session (i.e., radio resources are established and, if the user plane is to be activated, an N3 tunnel is established) without sending paging messages to the (R)AN node and the UE.

[0295] Step 4b, Paging [Conditional].

[0296] If the UE is in CM-IDLE state for 3GPP access and the PDU Session ID received from the SMF in step 3a is associated with 3GPP access, then based on local policy, the AMF decides to notify the UE via 3GPP access even if the UE is in CM-CONNECTED state for non-3GPP access, the AMF may send a paging message to the NG-RAN node via 3GPP access.

[0297] If the UE is registered via both 3GPP access and non-3GPP access in the same PLMN, the UE is in CM-IDLE state in both 3GPP access and non-3GPP access, and the PDU Session ID in step 3a is associated with non-3GPP access, the AMF sends a paging message with the associated access "Non-3GPP" to the NG-RAN node via 3GPP access.

[0298] If the UE is in RM-REGISTERED and CM-IDLE and is reachable in 3GPP access, the AMF sends a paging message (NAS ID for paging, Registration Area list, Paging DRX length, Paging Priority, access associated to the PDU Session question) to the (R)AN node of the registration area, and the NG-RAN node then pages the UE, including the access associated to the PDU Session in the paging message (if received from the AMF).

[0299] Different paging policies can be configured at the AMF using different combinations of DNN, PPI (if supported), ARP, and 5QI. For the RRC-Inactive state, different paging policies can be configured at the (R)AN using different combinations of PPI, ARP, and 5QI.

[0300] If the AMF receives a Namf_Communication_N1N2Message Transfer message indicating an ARP value associated with a priority service (e.g. MPS, MCS) (as configured by the operator) while waiting for the UE to respond to a request message sent without paging priority, another paging message with an appropriate paging priority should be sent. For a subsequently received Namf_Communication_N1N2Message Transfer message with the same or higher priority, the AMF may determine whether to send the paging message with the appropriate paging priority according to local policy.

[0301] The paging policy may include: paging retransmission scheme (e.g., paging repetition frequency or interval time); determination of whether to send paging messages to (R)AN nodes under certain AMF high load conditions; and whether to apply sub-area based paging (e.g., last known cell ID or first page in a TA, and retransmit in all registered TAs).

[0302] The AMF and (R)AN may support further paging optimization to reduce the signaling load and network resources for paging by one or more of the following means: AMF implements a specific paging strategy (e.g., sending the N2 Paging message to the (R)AN node that last served the UE); AMF considers the information provided by the (R)AN on recommended cells and NG-RAN nodes when transitioning to the CM-IDLE state. The AMF considers the (R)AN node-related part of this information to determine the (R)AN nodes to be paged and provides information about the recommended cells in the N2 Paging message to each of these (R)AN nodes.

[0303] Step 4c, NAS Notification.

[0304] If the UE is registered for both 3GPP and non-3GPP access in the same PLMN, and the UE is in CM-CONNECTED state for the 3GPP access and the PDU Session ID in step 3a is associated with the non-3GPP access, the AMF sends a NAS Notification message containing the non-3GPP access type via the 3GPP access point to the UE and sets a Notification timer. Step 5 is omitted.

[0305] If the UE is registered for both 3GPP and non-3GPP access in the same PLMN, and the UE is in CM-CONNECTED state in the non-3GPP and in CM-IDLE state in the 3GPP, and the PDU Session ID is associated with the 3GPP access in step 3a, and the AMF decides based on local policy to notify the UE via the non-3GPP access, the AMF may send a NAS Notification message containing the 3GPP access type to the UE via the non-3GPP access and set the Notification timer.

[0306] It should be understood that Figures 3 and 4 introduce the current service request process using the 5G system as an example. The service request process involved in this application is not limited to the steps shown in Figures 3 and 4.

[0307] As shown in Figures 3 and 4, a UE must be connected to the RAN to initiate a service request or receive a paging call from the core network. If the interface between the RAN and the core network elements, such as the N2 interface between the RAN and the AMF or the N3 interface between the RAN and the UPF, is restricted, the UE cannot complete the service request process shown in Figure 3, and the core network element's paging operation for the UE cannot be sent to the RAN, making it impossible to page the UE.

[0308] For example, limited interface connectivity can be caused by an interface being unresponsive, such as an access network device sending a data packet to a core network element, but the core network element does not respond. Alternatively, the interface may be experiencing severe packet loss, or transmission limitations, such as poor satellite link conditions resulting in very slow transmission speeds. Furthermore, scenarios where interface connectivity is limited include, but are not limited to, connection failures, connection failures, and so on.

[0309] To address the aforementioned issue of a UE being unable to complete the service request process, this application presents a communication method 500. This method can respond to a UE's service request even when the interface connection between the access network device RAN and the core network element is limited, thereby increasing network availability and resilience. The following describes an embodiment of the communication method 500 with reference to Figures 5 to 16. Examples 1 to 6 describe the uplink service request process, while Examples 7 to 12 describe the downlink service request process.

[0310] Example 1:

[0311] Figure 5 is a schematic diagram of the interaction process of a communication method 500 according to an embodiment of the present application, which includes a terminal device, a first access network device, a second access network device, a first core network element, or a second core network element. The communication method 500 can be performed by the above-mentioned terminal device, the first access network device, the second access network device, the first core network element, or the second core network element, or by a module and / or device (for example, a chip or an integrated circuit, etc.) with corresponding functions installed in the terminal device, the first access network device, the second access network device, the first core network element, or the second core network element. This application does not limit this. As shown in Figure 5, the communication method 500 includes steps S510 to S560.

[0312] Step S510: The terminal device sends a first service request message to the first access network device.

[0313] Correspondingly, the first access network device receives a first service request message from the terminal device.

[0314] Specifically, step S510 is the same as step 1 shown in Figure 3, and the function of the first service request message is the same as the function of the service request in step 1 shown in Figure 3, which is specifically used to request the core network network element to provide services for the terminal device, or in other words, through the first access network device, request the first core network network element that has an interface connection with the first access network device to provide services for the terminal device. Among them, the first core network network element and the first access network device can be connected through the N2 interface, that is, the first core network network element can be the AMF mentioned above. In other embodiments of the present application, the first core network network element and the first access network device can be connected through other interfaces, such as the N3 interface. In this case, the first core network network element can be a UPF. The present application does not limit the interface connection method between the first access network device and the first core network network element.

[0315] It should be understood that the first access network device can be the RAN mentioned above, and can also be referred to as the source RAN to reflect that the terminal device establishes a connection with the core network through the first access network device. The terminal device can be the UE mentioned above, and the first access network device is the access network device to which the terminal device is currently connected.

[0316] In an embodiment of the present application, the first service request message may include an AN parameter, which is parameter information sent by the terminal device to the first access network device. The AN parameter may include identification information of the terminal device, for example, the identification information of the terminal device may be a temporary mobile subscriber identity (TMSI) of the terminal device, such as a short term mobile subscriber identity (S-TMSI) or a radio network temporary identifier (RNTI), a user identification code such as an international mobile subscriber identity (IMSI) or a mobile station international subscriber directory number (MSISDN), or a subscription permanent identifier (SUPI), etc. The first service request message may also include content in the AN information in Figure 3, such as an activated PDU session, an allocated PDU session, etc., which is not limited in this application.

[0317] Step S520: The first access network device sends a first connection message through a first relay transmission path.

[0318] Correspondingly, the second access network device receives the first connection message through the first relay transmission path.

[0319] According to the above, the scenario in which the present application is applied is a scenario in which the interface connection between the first access network device and the first core network element is limited, such as the limited N2 interface connection between the RAN and the AMF or the limited N3 interface connection between the RAN and the UPF. At this time, when the first access network device receives the first service request message sent by the terminal device, it cannot send the first connection message directly to the first core network element in the core network that establishes a connection with the terminal device, and thus cannot establish an uplink service request process. Therefore, in the technical solution of the present application, the first connection message sent by the first access network device can be forwarded through a second access network device with a complete interface connection, and the first connection message can be forwarded to the first core network element, such as the AMF or the UPF, so that the first core network element can provide services to the terminal device, so that the core network is still available.

[0320] Specifically, the first relay transmission path includes a message transmission path between a first access network device and a second access network device. For example, the first access network device may establish a connection with the second access network device via random access or a pre-configured backup interface. In this case, the first connection message may directly reach the second access network device via the first relay transmission path. For another example, the first access network device may establish a connection with a third access network device via random access or a pre-configured backup interface, and the third access network device may establish a connection with the second access network device via random access or a pre-configured backup interface. In this case, the first relay transmission path is from the first access network device to the third access network device and then to the second access network device.

[0321] Exemplarily, the access method may be a registration method in the prior art or an IAB access process. For example, the first access network device described above switches its mode to terminal device mode and then randomly accesses the second access network device using the terminal device process. As another example, the access method may be that the first access network device accesses the second access network device via a pre-configured backup interface, which can be automatically activated when the connection between the first access network device and the first core network element, such as the N2 / N3 interface, is restricted.

[0322] The first access network device, the second access network device, and the third access network device (optional) can be connected via Xn or other horizontal device interfaces. The first access network device, the second access network device, and the third access network device can be connected via a wired connection, such as via a router, or can be connected via a wireless connection, such as via a microwave connection. This application does not limit the connection method between access network devices.

[0323] It should be understood that the reason the first relay transmission path can include a third access network device is that after the first access network device connects to the third access network device, if the interface between the third access network device and the core network element also has limited connectivity, the third access network device will need to connect to another access network device, such as a second access network device that has a complete connection with the second core network element, or other access network device with limited connectivity, before further access is achieved. In other words, the access network device between the first access network device and the second access network device also has limited connectivity with the interface between the core network element. In other words, the first relay transmission path will not terminate until access is reached to an access network device that has a complete connection with the core network element.

[0324] It's worth noting that the first relay transmission path is the path by which a message can reach the second access network device from the first access network device. The networking between multiple access network devices described above is merely an example. The first relay transmission path can also be a tunnel between the first access network device and the second access network device. This application does not limit the type of the first relay transmission path, nor does it limit the number or type of communication devices between the first access network device and the second access network device. The following embodiments will provide specific methods for determining the first relay transmission path.

[0325] Specifically, the first connection message has the same function as the N2 message in step 2 shown in Figure 3, namely, it is used to instruct the first core network element to provide services to the terminal device. The first core network element is a core network element that originally has a complete interface connection with the first access network device. In the embodiment of the present application, the interface between the first core network element and the first access network device has limited connection due to reasons such as connection failure to meet requirements / connection fault / connection failure.

[0326] In an embodiment of the present application, the first connection message may include identification information of the first access network device, identification information of the terminal device, and path indication information. The identification information of the first access network device may be an ID of the first access network device, used to indicate the access network device establishing the service request process, or to indicate the access network device to which the first connection message is sent; the identification information of the terminal device may be the TMSI of the terminal device, used to indicate to the first core network element the terminal device requiring service; and the path indication information is used to indicate the first relay transmission path.

[0327] For example, the path indication information may be the ID of each RAN in the first relay transmission path, such as the group ID of the consensus group or the ID of the entire RAN (e.g., the gNB ID), or routing information for each RAN, such as an IP address or MAC address. Furthermore, a communication device along the first relay transmission path can use the path indication information to find the corresponding next node. In some embodiments of the present application, the communication device in the first relay transmission path may have variable path indication information. For example, when a first connection message is sent from a first access network device to a third access network device, the third access network device may determine, based on the connection status between the third access network device and the second access network device or core network element, whether to send the first connection message to the second access network device as indicated by the original path indication information, or to modify the path indication information and forward the first connection message to another access network device or directly to a core network element connected to the second access network device. Furthermore, the path indication information may indicate one or more relay transmission paths, including the first relay transmission path. The method for determining the path indication information will be described in detail below and is not further elaborated here.

[0328] Optionally, the first connection message may also include identification information of the service request initiated by the terminal device, such as the ID of the service request, which is used to identify which service request it is, so as to subsequently locate the service request initiated by the terminal device to the first core network element from multiple service requests.

[0329] Step S530: The second access network device sends a first connection message to the second core network network element.

[0330] Correspondingly, the second core network element receives the first connection message from the second access network device.

[0331] The function of the first connection message and the content included in the message can refer to the above description.

[0332] It should be understood that, as mentioned above, the interface connection between the second access network device and the second core network element is complete, and therefore, the second access network device can also be regarded as an escape interface.

[0333] Optionally, the interface between the second access network device and the second core network network element can be implemented through a non-terrestrial network (NTN) communication system, such as a satellite communication network, a high altitude platform system (HAPS) and an air-to-ground network. For example, a satellite communication system may include a satellite, and there is a terminal device on the satellite to communicate with a ground base station. Among them, the satellite may refer to a non-ground base station or non-ground equipment such as an unmanned aerial vehicle, a hot air balloon, a low-orbit satellite, a medium-orbit satellite, and a high-orbit satellite. The NTN communication system can be deployed alone or as a supplement to the ground network. In this way, when there can be one or more connection means between the second access network device and the second core network network element, even if the original interface connection is limited, it can be switched to a satellite connection, etc., thereby ensuring that the interface connection between the second access network device and the second core network network element is complete.

[0334] Step S540: Determine whether the second core network element is a core network element that establishes a connection with the terminal device.

[0335] Specifically, when a terminal device initiates a service request, the first access network device needs to send a first connection message to the second core network element, and then the second core network element determines whether it is the same core network element as the first core network element that established a connection with the terminal device mentioned above. The reason is that an access network device will connect to one core network element, and there may be situations where different access network devices are connected to the same core network element. In other words, the interface connection between the first access network device and the first core network element is limited, and the interface connection between the second access network device and the first core network element may be complete.

[0336] Optionally, the second core network element can obtain the identification information of the first core network element based on the identification information of the terminal device contained in the first connection message, and then determine whether it is the same as the first core network element based on the identification information of the first core network element. For example, the identification information of the terminal device can be a TMSI, wherein a part of the TMSI generation algorithm is generated based on the ID of the first core network element connected to the terminal device. Then, the second core network element can decode and obtain the ID of the first core network element through the TMSI, and then compare its own ID with the ID of the first core network element to determine whether they are the same. For another example, the ID of the first core network element can be queried from a third party, and the third party can be a mapping relationship between the TMSI of the terminal device and the ID of the core network element. As mentioned above, the identification information of the terminal device can also be an IMSI or MSISDN, or it can be a SUPI, etc.

[0337] Optionally, the second core network element may determine whether the terminal device has established a connection with itself, such as establishing a NG interface application protocol (NGAP) connection, based on the identification information of the terminal device included in the first connection message. If it is determined that the terminal device has established a connection with the second core network element, the second core network element is determined to be the same as the first core network element; if it is determined that the terminal device has not established a connection with the second core network element, the second core network element is determined to be different from the first core network element.

[0338] If the second core network element is the same as the first core network element, the second core network element can directly provide services to the terminal device; if the second core network element is different from the first core network element, the second core network element needs to forward the received first connection message to the first core network element, and then the first core network element provides services to the terminal device.

[0339] Optionally, when the second core network element is different from the first core network element, or in other words, the second core network element is not the core network element that establishes a connection with the terminal device, the second core network element may determine the first core network element by pre-configuration, for example, by querying the address of the first core network element through a network repository function (NRF) based on the ID of the first core network element mentioned above. In this way, the second core network element may send the first connection message to the first core network element.

[0340] If the second core network element fails to find the address of the first core network element, the second core network element may send a failure response message to the second access network device, and the second access network device may send the failure response message to the first access network device via the first relay transmission path. After receiving the failure response message forwarded by the first access network device, the terminal device confirms that the uplink service request process has failed.

[0341] In the case that the second core network element is the same as the first core network element, the method 500 includes steps S550a and S560a.

[0342] Step S550a: The second core network element sends a first connection response message to the second access network device.

[0343] Correspondingly, the second access network device receives a first connection response message from the second core network network element.

[0344] Specifically, the first connection response message is used to indicate the service provided by the second core network element, such as data provided by the second core network element, etc. The first connection response message may also include at least one of the identification information of the terminal device, the identification information of the first access network device, and the path indication information.

[0345] Step S560a: The second access network device sends a first connection response message through the first relay transmission path.

[0346] Correspondingly, the first access network device receives the first connection response message through the first relay transmission path. The function and content of the first connection response message are as described above.

[0347] In the case that the second core network element is different from the first core network element, the method 500 includes steps S545, S548, S550b and S560b.

[0348] Step S545: The second core network element sends a first connection message to the first core network element.

[0349] Correspondingly, the first core network element receives a first connection message from the second core network element. The function and content of the first connection message are as described above. After receiving the first connection message, the first core network element starts to provide services for the terminal device.

[0350] Optionally, a connection may be established between the second core network element and the first core network element via a network protocol, and the second core network element may send the first connection message to the first core network element.

[0351] Optionally, the second core network element may determine the address of the first core network element based on a pre-set mapping relationship between the core network element ID and the core network element address and the ID of the first core network element determined in step S540, and then send the first connection message to the first core network element. The pre-set mapping relationship may be queried from a network repository function (NRF).

[0352] Step S548: The first core network element sends a first connection response message to the second core network element.

[0353] Correspondingly, the second core network element receives the first connection response message from the first core network element. The function and content of the first connection response message are as described above.

[0354] Step S550b: The second core network element sends a first connection response message to the second access network device.

[0355] Correspondingly, the second access network device sends a first connection response message from the second core network element. Step S550b can refer to step S550a and will not be described in detail here.

[0356] Step S560b: The second access network device sends a first connection response message through the first relay transmission path.

[0357] Correspondingly, the first access network device receives the first connection response message via the first relay transmission path. Step S560b may refer to step S560a and will not be described in detail here.

[0358] In the technical solution of communication method 500, when the interface connection between a first access network device or one or more access network devices connected to the first access network device and a core network element is limited, the first connection message is forwarded via a relay transmission path to a second access network device with a complete interface connection, allowing the core network to still respond to service requests initiated by terminal devices. This increases the availability of the core network and enhances its network resilience.

[0359] To determine the first relay transmission path, the present application describes a path determination method based on a consensus group. Examples 2 and 3 describe methods for establishing a consensus group, while Examples 4 through 6 describe methods for determining the first relay transmission path based on a consensus group. By establishing a consensus group and determining the first relay transmission path based on the consensus group, the first connection message is sent via the first relay transmission path in Example 1, thereby ensuring the availability of the core network.

[0360] Example 2:

[0361] Figure 6 is a schematic diagram of the interaction process of a communication method 600 according to an embodiment of the present application, which includes a first access network device and a second access network device. The method shown in Figure 6 can be performed by the first access network device and the second access network device, or by modules and / or devices (e.g., chips or integrated circuits, etc.) with corresponding functions installed in the first access network device and the second access network device, and this application does not limit this. As shown in Figure 6, the communication method 600 includes steps S610 to S630, which can occur before method 500 or before step S520 in method 500.

[0362] Step S610: The first access network device determines that the interface connection with the first core network element is restricted.

[0363] For example, as mentioned above, limited interface connectivity can occur when the interface is unresponsive, for example, when an access network device sends a data packet to a core network element, but the core network element does not respond. Alternatively, the interface may be experiencing severe packet loss. Alternatively, limited interface transmission can occur, for example, when poor satellite link conditions result in very slow transmission speeds. Furthermore, scenarios where limited interface connectivity occurs include, but are not limited to, connection failures, connection failures, and so on.

[0364] When the first access network device finds that the current interface connection is limited, it can detect the access network device signal nearby. For example, the first access network device temporarily switches to the terminal device mode to detect and access the adjacent access network device.

[0365] Step S620: The first access network device is connected to the second access network device.

[0366] Optionally, the access method may be a registration method in the prior art or an IAB access process. For example, the first access network device mentioned above switches its mode to terminal device mode and then randomly accesses the second access network device using the terminal device process.

[0367] Optionally, the access method can also be that the first access network device accesses the second access network device through a pre-configured backup interface, and the pre-configured backup interface can be automatically activated when the connection between the first access network device and the first core network network element, such as the N2 / N3 interface, is restricted.

[0368] This application does not limit the access method. The access method between access network devices can also be achieved through wired connection such as router connection or wireless connection such as microwave connection.

[0369] After receiving the access request, the second access network device determines whether it can directly establish an ad hoc network based on its local configuration, such as the interface connection with the core network element. Taking the situation shown in Figure 6 as an example, if the interface connection between the second access network device and the second core network element is complete, step S630 can be executed.

[0370] Step S630: establish a consensus group, determine the group identifier, and select one of the access network devices as the leader node.

[0371] Specifically, the first access network device and the second access network device establish a consensus group through a self-organizing network, select one of the access network devices as a temporary service node or a leader node, and determine to have a group identifier.

[0372] It should be understood that the condition for establishing a consensus group is that all access network devices between the first access network device and the second access network device (including the first access network device and the second access network device) are directly or indirectly connected to or connected to one or more other access network devices, and therefore all access network devices are capable of direct or indirect (multi-hop) connections. In other words, a necessary condition for networking is that the access network devices are routable. Example 3 below will describe the situation where at least three access network devices establish a consensus group.

[0373] Optionally, the ad hoc network between the first access network device and the second access network device may be established in a wired manner, in a wireless manner, or in a hybrid manner of wired and wireless.

[0374] Optionally, the leader node can be selected based on the fault tolerance algorithm mentioned above. The detailed election process between multiple access network devices will be introduced in Example 3, which will not be repeated here. In the embodiment of the present application, the access network devices other than the leader node in the consensus group can be dynamically changed. In other words, the access network devices other than the leader node can join or exit the consensus group. Since all access network devices in the consensus group synchronize data after the consensus algorithm is executed, the joining or exit of the access network devices before the execution of the consensus algorithm does not affect the normal execution of the consensus group data synchronization.

[0375] Optionally, data synchronization between access network devices can be performed through different consensus groups, or in other words, the data synchronization process can be performed through different leader nodes. For example, in a first time period, a first consensus group can be established between multiple access network devices, and the first access network device can be elected as the leader node. Data synchronization of the first consensus group can then be achieved through the first access network device during the first time period. In a second time period, a second consensus group can be established between multiple access network devices, and the second access network device can be elected as the leader node. Data synchronization of the second consensus group can then be achieved through the second access network device during the second time period.

[0376] Optionally, the leader node can exit the consensus group. In this case, before the consensus algorithm is executed, the multiple access network devices can re-elect a leader node, or the consensus group can add a new leader node to synchronize data in the consensus group after the previous leader node exits.

[0377] Optionally, the group identifier may be generated after the consensus group is established, may be generated each time a consensus group is established, and may be broadcast by the leader node to other nodes in the consensus group after the consensus group is initially established.

[0378] Example 2 introduces the case where the consensus group includes only two access network devices, and Example 3 will introduce the case where the consensus group includes multiple access network devices.

[0379] Example 3:

[0380] Figure 7 shows an interactive flow chart of another communication method 700 for establishing a consensus group according to an embodiment of the present application. In this embodiment, at least one third access network device is included between the first access network device and the second access network device. For ease of description, Figure 7 uses a single third access network device as an example. The process for multiple third access network devices is simply a repetition of the process for a single third access network device and is not further described herein. Communication method 700 includes steps S710 to S750.

[0381] Step S710: The first access network device determines that the interface connection with the first core network element is restricted.

[0382] Step S710 may refer to step S610 in embodiment 2.

[0383] Step S720: The first access network device is connected to the third access network device.

[0384] Step S720 may refer to step S620 in embodiment 2.

[0385] Step S730: The third access network device determines that the interface connection with the third core network element is restricted.

[0386] Different from Example 2, after the third access network device receives the access request from the first access network device, the interface connection with the third core network network element is restricted based on the local configuration. Therefore, the third access network device is not the end point of the relay transmission path, and it is necessary to continue to find an access network device with a complete interface connection with the core network network element.

[0387] Optionally, during the access process, the third access network device may also access one or more other access network devices with limited interface connectivity, and the one or more access network devices may then continue to search for an access network device with a complete interface connection to the core network element until access is reached. For ease of description, the third access network device and the one or more access network devices with limited interface connectivity that may be accessed are collectively referred to as "relay access network devices" or relay RANs. The access method for these relay access network devices can refer to the description of step S720, that is, the registration process or IAB access process in the prior art can be used, such as temporarily switching to terminal device mode.

[0388] Step S740: The third access network device is connected to the second access network device.

[0389] Step S740 may refer to the description of step S620 and step S720 .

[0390] Step S750: establish a consensus group, determine the group identifier, and select one of the access network devices as the leader node.

[0391] In other embodiments of the present application, the first access network device can be connected to multiple third access network devices. The multiple third access network devices are then connected to one or more relay access network devices, or to the second access network device, through the random access or pre-configured spare interface mentioned above. The relay access network device transfers access hop by hop according to the transmission rules to form a mesh network. In the mesh network, each access network device can be connected to one or more relay access network devices. For example, the first access network device can be connected to access network device A and access network device B through the random access or pre-configured spare interface mentioned above, access network device A can be connected to access network device C through the random access or pre-configured spare interface mentioned above, and access network device B can be connected to access network device D through the random access or pre-configured spare interface mentioned above. Until one or more relay access network devices, such as the access network device C or access network device D mentioned above, are connected to the second access network device and can be connected to the first core network network element or the second core network element, a consensus group can be established for all the connected relay access network devices (such as the above-mentioned access network devices A, B, C and D) and the first access network device and the second access network device.

[0392] It is worth noting that the relay access network device that can access the second access network device can establish a consensus group through active self-organizing networking, and the relay access network device that cannot access the second access network device can passively establish a consensus group by receiving a request message. At this time, the first access network device, the second access network device, and all relay access network devices are directly or indirectly connected to another or multiple access network devices and have the ability to connect directly or indirectly (multi-hop). Furthermore, a consensus group can be established through a wired or wireless self-organizing network, and one of the access network devices is selected as the leader node to determine a group identifier.

[0393] Alternatively, the leader node can be selected based on a fault-tolerant algorithm such as Paxos, Raft, or ZooKeeper as described above. This application does not impose any restrictions on the method for selecting the leader node. For ease of understanding, this embodiment of the application provides an example of selecting a leader node based on the Paxos fault-tolerant consensus algorithm, including stages 1 to 3.

[0394] Phase 1: Prepare phase. Any proposing access network device (proposer RAN) sends a prepare request to other access network devices. The prepare request is used to indicate that it is ready to establish a consensus group. Other access network devices make a promise to the received prepare request.

[0395] Phase 2: Accept Phase: After receiving the majority of commitments from other access network devices, the proposing access network device sends a propose request to the other access network devices, and the other access network devices receive (accept) the received propose request.

[0396] Phase 3: Learn. After the proposing access network device receives the majority of acceptances from other access network devices, it is deemed a success and a resolution is formed. The resolution is then sent to all remaining nodes, making the proposing access network device the leader node.

[0397] Examples 2 and 3 describe how to establish a consensus group and elect a leader node. A consensus group comprising multiple access network devices is established through a fault-tolerant algorithm. The consensus group can determine the above-mentioned first relay transmission path to implement an uplink service request or a downlink paging request. In addition, the consensus group can also achieve consistency between multiple access network devices, ensuring the reliability and stability of the core network in the embodiments of the present application. Examples 4 to 6 will describe how to determine the first relay transmission path based on the consensus group, wherein Examples 4 to 6 respectively provide the interaction processes under three different leader nodes.

[0398] Example 4:

[0399] Figure 8 shows an interactive flow chart of a method 800 for determining a first relay transmission path. In method 800, a first access network device serves as the leader node in a consensus group, where the consensus group includes the first access network device, a second access network device, and possibly at least one third access network device. In the communication network shown in Figure 8, the first access network device connects to the third access network device, and the third access network device connects to the second access network device, thereby forming a consensus group. Method 800 includes steps S810 to S830.

[0400] Step S810: The terminal device sends a first service request message to the first access network device.

[0401] Correspondingly, the first access network device receives the first service request message from the terminal device. Step S810 can refer to step S510 in embodiment 1, and the function and content of the first service request message can refer to the description of embodiment 1.

[0402] Step S811: The first access network device sends a connection status request message to the third access network device.

[0403] Correspondingly, the third access network device receives a connection request message from the first access network device. Specifically, the connection request message is used to request the third access network device to determine the connection relationships with other access network devices. In other words, the connection request message is used to request the third access network device to determine which access network devices are connected to the third access network device and which access network devices the third access network device is connected to.

[0404] Optionally, the connection status request message may include the consensus group's group identifier and / or connection attribute information. The consensus group's group identifier is used to ensure that the access network device in the connection status feedback information is an access network device in the consensus group; the connection attribute information may include information such as the requested access network device's connection bandwidth, latency, connection type (wired or wireless), jitter, time required to restore the connection, and the presence or absence of security protection.

[0405] For example, the connection bandwidth of an access network device may be the maximum transmission bandwidth after the access network device is connected, the latency may be the average or maximum latency after the access network device is connected, the jitter may be the delay interval, the time taken to restore the connection may be the time it takes for the access network device to establish a connection with another access network device, and the presence or absence of security protection may be whether the data transmitted by the access network device is encrypted or integrity-protected. In embodiments of the present application, the connection attribute information may also be other attributes that identify the connection status between access network devices, which is not limited in this application.

[0406] Step S812: The third access network device sends a connection status feedback message to the first access network device.

[0407] Correspondingly, the first access network device receives a connection status feedback message from the third access network device.

[0408] The third access network device determines the connection relationship based on the group identifier and provides feedback to the first access network device. Specifically, the connection status feedback message includes the connection relationship between the third access network device and other access network devices, or in other words, which access network devices are connected to the third access network device, or which access network devices the third access network device is connected to. In other words, the connection status feedback message includes at least one access network device, and this at least one access network device has a connection relationship with the third access network device, either accessing or being accessed.

[0409] Optionally, the connection status feedback message may include a connection relationship or a message transmission path, for example, the third access network device is connected to the second access network device (or, the third access network device->the second access network device).

[0410] Optionally, the connection status feedback information may also include connection attribute information determined by the third access network device, such as the connection bandwidth / delay / connection type (wired or wireless) / jitter / time required to restore the connection / whether there is security protection, etc.

[0411] Step S815: The first access network device sends a connection status request message.

[0412] Correspondingly, the second access network device receives the connection status request message.

[0413] Step S816: The second access network device sends a connection status feedback message.

[0414] Correspondingly, the first access network device receives a connection status feedback message.

[0415] Steps S815 and S816 may be sent in a multi-hop manner. For example, the first access network device may first send the connection request message to the third access network device, and the third access network device may then send the connection request message to the second access network device, and the same applies to step S816.

[0416] The connection status request message in step S815 can refer to the description in step S811, and the connection status feedback information in step S816 can refer to the description in step S812. For example, the connection status request message may include the group identifier of the consensus group and / or the attribute information of the connection, such as the connection bandwidth / latency / connection type (wired or wireless) / jitter / time used to restore the connection / whether or not security protection is present, etc.; the connection status feedback message may include the connection relationship between access network devices and / or the attribute information of the connection, such as the connection bandwidth / latency / connection type (wired or wireless) / jitter / time used to restore the connection / whether or not security protection is present, etc. This article will not elaborate on this.

[0417] It should be understood that steps S815 and S816 are also applicable to relay access network devices that are indirectly connected to the first access network device (with multiple hops in between). In other words, in the network shown in Figure 8, if there are multiple relay access network devices between the third access network device and the second access network device, the first access network device can also interact with the multiple relay access network devices through steps S815 and S816 to obtain connection status feedback messages from the multiple relay access network devices. This application does not elaborate on this situation.

[0418] Step S818: The first access network device determines a first relay transmission path.

[0419] Specifically, the first access network device determines the first relay transmission path based on the received connection status feedback information. Taking the communication network shown in Figure 8 as an example, the connection status feedback information received by the first access network device from the third access network device is "third access network device -> second access network device", and the connection status feedback information received by the first access network device from the second access network device is "second access network device -> second core network network element". Therefore, the first access network device determines the first relay transmission path as "first access network device -> third access network device -> second access network device" or "first access network device -> third access network device -> second access network device -> second core network network element".

[0420] Optionally, the first access network device may indicate the first relay transmission path using path indication information. For example, the path indication information may include the aforementioned path description "first access network device -> third access network device -> second access network device," may include a group identifier or a network-wide identifier (such as a gNB ID) for each access network device, or may include routing information for each access network device, such as an IP address or MAC address.

[0421] It is worth noting that the relay transmission paths determined by the first access network device may be multiple, and the first relay transmission path is only one of the multiple relay transmission paths. For example, as mentioned above, when establishing a consensus group, multiple access network devices can form a mesh network, and one or more relay access network devices can be connected to the second access network device. Therefore, there can be multiple relay transmission paths that can reach the second access network device, or there can be multiple relay transmission paths with the same starting point and the same end point but different types of relay access network devices in the middle. The first access network device can select one of the multiple relay transmission paths, for example, the one with the shortest delay or the shortest total path length as the first relay transmission path.

[0422] Optionally, the first access network device can also determine the validity of the path indication information based on one or more challenge-response messages. Specifically, the first access network device sends one or more challenge messages to one or more access network devices in the consensus group, and the challenge message includes some random numbers or encryption keys, etc. After receiving the challenge message, one or more access network devices other than the first access network device in the consensus group use their own keys or algorithms to process the challenge message and generate response information. After receiving one or more response messages, the first access network device uses the same algorithm or key as that used to send the challenge message to verify the response message. If the verification is successful, it means that the communication path between the first access network device and the one or more access network devices is valid.

[0423] Step S820: The first access network device sends a first connection message through a first relay transmission path.

[0424] Correspondingly, the second access network device receives the first connection message through the first relay transmission path.

[0425] Step S830: The second access network device sends a first connection message to the second core network network element.

[0426] Correspondingly, the second core network element receives the first connection message from the second access network device.

[0427] Step S820 and step S830 may refer to step S520 and step S530 in embodiment 1, and the function and included content of the first connection message may refer to the description in embodiment 1.

[0428] It is worth noting that method 800 also includes step S540 and subsequent steps as shown in Figure 5. For ease of description, these steps are omitted in Example 4. For specific steps, please refer to the description of step S540 and subsequent steps in Example 1.

[0429] Example 5:

[0430] Figure 9 illustrates a method 900 for determining a first relay transmission path when a third access network device serves as a leader node. Method 900 includes steps S910 to S930. It is worth noting that the communication network shown in Figure 9 may include multiple third access network devices, as described above. For ease of description, Figure 9 uses a single third access network device as an example.

[0431] Step S910: The terminal device sends a first service request message to the first access network device.

[0432] Correspondingly, the first access network device receives the first service request message from the terminal device. Step S910 may refer to the description of step S510 in embodiment 1.

[0433] Step S911: The first access network device sends a relay service request message.

[0434] Correspondingly, the third access network device serving as the leader node receives the relay service request message. In other words, the leader node receives the relay service request message.

[0435] Specifically, the relay service request message is used to instruct the first access network device to request to send the first connection message via relay transmission, or to instruct the leader node to determine the relay transmission path so that the first access network device can send the first connection message.

[0436] Optionally, one or more relay access network devices may be included between the first access network device and the third access network device serving as the leader node. In this case, the relay service request message may reach the third access network device via multi-hop transmission. That is, the first access network device sends the relay service request message to the relay access network device, and the relay access network device then sends the relay service request message to the third access network device.

[0437] Optionally, the relay service request message may include identification information of the terminal device, such as TMSI.

[0438] After the third access network device receives the relay service request message, it may perform a subsequent step of determining the first relay transmission path.

[0439] Step S913: The third access network device sends a connection status request message.

[0440] Correspondingly, the first access network device receives the connection status request message.

[0441] Step S914: The third access network device receives a connection status feedback message.

[0442] Correspondingly, the first access network device receives a connection status feedback message.

[0443] Optionally, when the message transmission path between the first access network device and the third access network device includes one or more relay access network devices, the connection status request message and the connection status feedback message can be sent or received through multi-hop transmission.

[0444] Step S915: The third access network device sends a connection status request message.

[0445] Correspondingly, the second access network device receives the connection status request message.

[0446] Step S916: The third access network device receives a connection status feedback message.

[0447] Correspondingly, the second access network device sends a connection status feedback message.

[0448] Optionally, when the message transmission path between the third access network device and the second access network device includes one or more relay access network devices, the connection status request message and the connection status feedback message can be sent or received through multi-hop transmission.

[0449] Steps S913 to S916 may refer to steps S811, S812, S815, and S816 in Example 4. The connection status request message and the connection status feedback message may refer to the description in Example 4. For example, the connection status request message may be used to request the connection relationship between access network devices, and may include the group identifier of the consensus group or the connection attribute information such as the connection bandwidth / delay / connection type (wired or wireless) / jitter / time required to restore the connection / whether or not there is security protection of the access network device; the connection status feedback message may include the connection relationship between the access network devices or the connection attribute information of the access network devices. It is worth noting that steps S913 to S916 may be one hop (for example, the first access network device is directly connected to the third access network device) or multiple hops (for example, the first access network device and the third access network device include other relay access network devices).

[0450] In some embodiments of the present application, one or more relay access network devices may be included between the first access network device and the third access network device, or between the third access network device and the second access network device. The interaction process between the third access network device and the one or more relay access network devices may refer to steps S913 to S916. This document does not elaborate on this process.

[0451] Step S918: The third access network device determines a first relay transmission path.

[0452] Step S918 can refer to the description of step S818 in Example 4. For example, the first relay transmission path can be indicated by path indication information, or multiple relay transmission paths can be determined and one of them can be selected as the first relay transmission path, or the first relay transmission path can be determined based on one or more challenge-response.

[0453] For example, using the network shown in FIG9 , the third access network device may receive a connection status feedback message from the first access network device with the message transmission path "first access network device -> third access network device," and receive a connection status feedback message from the second access network device with the message transmission path "second access network device -> second core network element." Furthermore, based on the message transmission path "third access network device -> second access network device," the third access network device may summarize the connection status as "first access network device -> third access network device -> second access network device" or "first access network device -> third access network device -> second access network device -> second core network element."

[0454] Step S919: The third access network device sends a relay service response message.

[0455] Correspondingly, the first access network device receives a relay service response message. Specifically, the relay service response message includes the aforementioned path indication information or the first relay transmission path. Furthermore, the first access network device may send the first connection message via the first relay transmission path based on the path indication information or the first relay transmission path included in the relay service response message.

[0456] Step S920: The first access network device sends a first connection message through a first relay transmission path.

[0457] Correspondingly, the second access network device receives the first connection message through the first relay transmission path.

[0458] Step S930: The second access network device sends a first connection message to the second core network network element.

[0459] Correspondingly, the second core network element receives the first connection message from the second access network device.

[0460] Step S920 and step S930 may refer to the description of step S520 and step S530 in embodiment 1. The function and content of the first connection message may refer to the description of embodiment 1.

[0461] It is worth noting that method 900 also includes step S540 and subsequent steps as shown in Figure 5. For ease of description, these steps are omitted in Example 5. For specific steps, please refer to the description of step S540 and subsequent steps in Example 1.

[0462] Example 6:

[0463] 10 shows an interactive process of a communication method 1000 for determining a first relay transmission path when the second access network device serves as a leader node. The method 1000 includes steps S1010 to S1030.

[0464] Step S1010: The terminal device sends a first service request message to the first access network device.

[0465] Correspondingly, the first access network device receives the first service request message from the terminal device. Step S1010 may refer to step S510 in embodiment 1.

[0466] Step S1011: The first access network device sends a relay service request message.

[0467] Correspondingly, the second access network device receives the relay service request message. In other words, the leader node receives the relay service request message. The function and content of the relay service request message can be referred to the description of Example 5.

[0468] Optionally, when the message transmission path between the first access network device and the second access network device includes one or more third access network devices, the relay service request message may reach the second access network device through multi-hop delivery.

[0469] Step S1013: The second access network device sends a connection status request message.

[0470] Correspondingly, the first access network device receives the connection status request message.

[0471] Step S1014: The second access network device receives a connection status feedback message.

[0472] Correspondingly, the first access network device receives a connection status feedback message.

[0473] Optionally, when the message transmission path between the first access network device and the second access network device includes one or more third access network devices, the connection status request message and the connection status feedback message can be sent or received through multi-hop transmission.

[0474] Step S1015: The second access network device sends a connection status request message.

[0475] Correspondingly, the third access network device receives the connection status request message.

[0476] Step S1016: The second access network device receives a connection status feedback message.

[0477] Correspondingly, the third access network device sends a connection status feedback message.

[0478] Optionally, when the message transmission path between the third access network device and the second access network device includes one or more relay access network devices, the connection status request message and the connection status feedback message can be sent or received through multi-hop transmission.

[0479] Steps S1013 to S1016 may refer to steps S811, S812, S815 and S816 in Example 4, and the connection status request message and the connection status feedback message may refer to the description in Example 4. For example, the connection status request message may be used to request the connection relationship between access network devices, and may include the group identifier of the consensus group or the connection attribute information of the access network device, such as the connection bandwidth / delay / connection type (wired or wireless) / jitter / time required to restore the connection / whether there is security protection, etc.; the connection status feedback message may include the connection relationship between access network devices or the connection attribute information of the access network devices.

[0480] Step S1018: The second access network device determines a first relay transmission path.

[0481] Step S1018 may refer to the description of step S918 in embodiment 5.

[0482] Step S1019: The second access network device sends a relay service response message.

[0483] Correspondingly, the first access network device receives the relay service response message. The function and content of the relay service response message can refer to the description in embodiment 5, that is, including path indication information or the first relay transmission path.

[0484] Optionally, when the message transmission path between the first access network device and the second access network device includes one or more third access network devices, the relay service response message may be sent or received in a multi-hop delivery manner.

[0485] Step S1020: The first access network device sends a first connection message through a first relay transmission path.

[0486] Correspondingly, the second access network device receives the first connection message through the first relay transmission path.

[0487] Step S1030: The second access network device sends a first connection message to the second core network network element.

[0488] Correspondingly, the second core network element receives the first connection message from the second access network device.

[0489] Step S1020 and step S1030 may refer to the description of step S520 and step S530 in embodiment 1. The function and content of the first connection message may refer to the description of embodiment 1.

[0490] It is worth noting that method 1000 also includes step S540 and subsequent steps as shown in Figure 5. For ease of description, these steps are omitted in Example 6. For specific steps, please refer to the description of step S540 and subsequent steps in Example 1.

[0491] In general, in the technical solution of Example 1, when the connection between the first access network device and the first core network element is limited, the first access network device sends a first connection message to the second access network device via the first relay transmission path. The interface connection between the second access network device and the second core network element is complete, and the uplink service request process of the terminal device is implemented through the second core network element (for example, the second core network element is the same as the first core network element, or the second core network element is used to determine the first core network element), thereby improving the network resilience and reliability of the core network.

[0492] In the technical solutions of Examples 2 and 3, multiple access network devices, including the first access network device and the second access network device, can establish a consensus group through an ad hoc network and elect a leader node to ensure consistency of the consensus group. Furthermore, if connectivity between the first access network device and the first core network element is limited, the leader node of the consensus group can be used to determine the first relay transmission path.

[0493] The technical solutions of Examples 4 to 6 describe methods for determining a first relay transmission path when a first access network device, a second access network device, and a third access network device (or relay access network device) each serve as a leader node. Furthermore, this provides the feasibility of enabling a terminal device to implement an uplink service request when connectivity between the first access network device and the first core network element is limited.

[0494] The above primarily describes the process by which a terminal device implements an uplink service request in a scenario where the connection between a first access network device and a first core network element is limited. Based on the above description of the service request, it can be seen that during the downlink service request process, the core network also needs to initiate paging for the terminal device. However, in a scenario where the connection between the first access network device and the first core network element is limited, the paging operation initiated by the first core network element cannot reach the terminal device via the first access network device. Therefore, based on the above-described first relay transmission path, Examples 7 to 12 will describe the downlink service request process in a scenario where the connection between the first access network device and the first core network element is limited.

[0495] Example 7:

[0496] Figure 11 shows the interactive process of the communication method 1100. Among them, the network shown in Figure 11 includes the terminal device, the first access network device, the second access network device, the second core network network element mentioned above, and also includes the fourth core network network element. The communication method 1100 can be performed by the terminal device, the first access network device, the second access network device, the second core network network element and the fourth core network network element, or by modules and / or devices (for example, chips or integrated circuits, etc.) with corresponding functions installed in the terminal device, the first access network device, the second access network device, the second core network network element and the fourth core network network element. This application does not limit this. As shown in Figure 11, method 1100 includes steps S1110 to S1195.

[0497] It is worth noting that the communication network shown in Figure 11 is the situation where the first core network element and the second core network element mentioned in Example 5 are the same, and Example 8 will introduce the situation where the first core network element and the second core network element mentioned in Example 5 are different.

[0498] Step S1110: The fourth core network element receives a downlink message.

[0499] Step S1110 may refer to step 1 in the downlink service request process shown in Figure 4. The downlink message may be downlink data.

[0500] Optionally, the fourth core network element may be a UPF or an SMF, which is not limited in this application.

[0501] Step S1120: The fourth core network element sends a first connection transfer request message to the second core network element.

[0502] Correspondingly, the second core network element receives the first connection transfer request message from the fourth core network element.

[0503] Specifically, the first connection transfer request message has the same function as the N1N2_message transfer request in step 3a shown in Figure 4. In an embodiment of the present application, the first connection transfer request message may include identification information of the terminal device, for example, a TMSI such as an S-TMSI or an RNTI, or a user identification code such as an IMSI or an MSIMDN, or a subscription permanent identifier (SUPI), for use in the identification process of subsequent steps to determine the terminal device. Optionally, the identification information of the terminal device may also include a mixture of at least two of the identification information such as TMSI, IMSI, and SUPI.

[0504] Step S1150: The second core network network element recognizes that the terminal device accesses the core network via a relay, and determines identification information of the second access network device and the uplink service request.

[0505] It should be understood that when the second core network element identifies that a terminal device accesses the core network via a relay, or in other words, via the first relay transmission path described above, the second core network element needs to instruct the second access network device to send a paging request via the relay method used in the uplink service request process. This enables the downlink service request process initiated by the core network. The second core network element can determine the terminal device to be identified based on the terminal device's identification information in the first connection transfer request message.

[0506] Optionally, the second core network network element can be a method of identifying whether the terminal device accesses the core network through a relay method based on local records. For example, as shown in Example 5, the second core network network element needs to determine whether it is the same as the first core network network element through step S540. Then, in step S1150, the second core network network element can determine whether the terminal device accesses the core network through a relay method based on step S540 in the local record. The reason is that: in the existing uplink service request process shown in Figure 3, step S540 is not included, that is, the terminal device can directly access the first core network network element. Only when the terminal device accesses the core network through a relay method, the second core network network element needs to determine the first core network network element that provides services to the terminal device through step S540.

[0507] In other embodiments of the present application, the second core network element may determine that the terminal device accesses the core network via a relay by other means, for example, based on the path indication information recorded in the local record or the first relay transmission path. The present application does not limit the relay method for identifying the terminal device.

[0508] The reason why the second core network network element determines the identification information of the second access network device and the uplink service request is that: the second core network network element needs to determine the second access network device when the uplink service request is made, so as to send a paging request through the second access network device and the first relay transmission path; the second core network network element determines the identification information of the uplink service request so that the subsequent second access network device can determine the first access network device according to the identification information of the uplink service request, and then send the paging request to the first access network device.

[0509] Optionally, the local uplink history record may include identification information of the uplink service request. For example, the first connection message in steps S520 and S530 of Example 1 may include identification information of the uplink service request, which is recorded in the local uplink history record after the uplink service request. The second core network network element may determine the second access network device in the uplink service request process based on the identification information of the uplink service request recorded in the local uplink history record.

[0510] Step S1160: The second core network element sends a first paging request message to the second access network device.

[0511] Correspondingly, the second access network device receives a first paging request message from the second core network element. Specifically, the first paging request message is used to request to initiate paging to the terminal device.

[0512] Optionally, the first paging request message may include identification information of the uplink service request and / or identification information of the terminal device. The identification information of the uplink service request is used to indicate the uplink service request corresponding to the downlink service request and is used to determine the first access network device for the uplink service request, and the identification information of the terminal device is used to determine to which terminal device the paging is to be initiated.

[0513] Step S1170: The second access network device determines the first access network device and path indication information.

[0514] Optionally, when the second access network device receives the identification information of the uplink service request in the first paging request message, it can determine the first access network device and the historical routing record at the time of the uplink service request based on the local uplink log information. Example 9 will introduce this process in detail, and this article will not go into details here. Among them, the second access network device can be the identification information of the first access network device, such as the ID, or the routing information of the first access network device, such as the IP address; the historical routing record can include path indication information or the first relay transmission path.

[0515] Optionally, the second access network device may also obtain the first access network device and the above-mentioned historical routing records from DLT or blockchain through distributed accounting or consensus algorithm.

[0516] Step S1180: The second access network device sends a first paging request message through the first relay transmission path.

[0517] Correspondingly, the first access network device receives the first paging request message through the first relay transmission path.

[0518] The description of the first relay transmission path can refer to the introduction in Example 1, and the description of the first paging request message can refer to step S1160. The message transmission method between the first access network device and the second access network device can refer to the description of the previous embodiment, such as implementing multi-hop transmission through one or more relay access network devices, etc., which is not detailed here.

[0519] Step S1190: The first access network device initiates paging to the terminal device.

[0520] In an embodiment of the present application, the first access network device can determine the terminal device that needs to be paged based on the identification information of the terminal device in the first paging request message. Optionally, the first access network device can initiate paging through one of the identification information of the terminal device included in the first paging request message, or can page the terminal device through multiple identification information of the terminal device, such as TMSI and RNTI. For example, the first paging request message includes the TMSI of the terminal device, and the local record of the first access network device includes the correspondence between the TMSI and RNTI of the terminal device, and then the first access network device can determine the RNTI of the terminal device and use the RNTI to initiate paging to the terminal device.

[0521] After the first access network device initiates paging to the terminal device, if the terminal device responds to the first access network device and re-establishes an RRC (radio resource control) connection, the first access network device can be considered to have successfully initiated paging to the terminal device. If the first access network device successfully initiates paging to the terminal device, step S1195 is executed, and the first access network device sends a paging success notification message via the first relay transmission path.

[0522] Correspondingly, the second core network network element receives a paging success notification message from the second access network device.

[0523] Specifically, the paging success notification message is used to notify the second core network element to instruct the terminal device to perform a paging action.

[0524] In other embodiments of the present application, method 1100 may further include step 4c in the prior art shown in FIG. 4 or the second core network element sending an N1N2_message transfer notification to the fourth core network element, etc., which will not be elaborated in this application.

[0525] Example 8:

[0526] While Example 7 describes the case where the first core network element and the second core network element are identical, Example 8 describes the case where the first core network element and the second core network element are different. Compared to Example 7, Step S1220 and Step S1250 in Example 8 are different, and the remaining steps can refer to the description of Example 7.

[0527] Figure 12 illustrates the interaction flow of communication method 1200. Compared to communication method 1100, in communication method 1200, the first core network element is used to identify that a terminal device accesses the core network via a relay, and the second core network element is used to determine identification information of a second access network device and an uplink service request. Communication method 1200 includes steps S1210 to S1295.

[0528] Step S1210: The fourth core network element receives a downlink message.

[0529] Step S1210 may refer to the description of step 1 and step S1110 in the downlink service request process shown in Figure 4. The downlink message may be downlink data.

[0530] Step S1220: The fourth core network element sends a first connection transfer request message to the first core network element.

[0531] Correspondingly, the first core network element receives a first connection transfer request message from the fourth core network element. The first connection transfer request message can refer to the description of step S1120 of embodiment 7.

[0532] Step S1230: The first core network network element recognizes that the terminal device accesses the core network via a relay.

[0533] The determination method of step S1230 may refer to the description of step S1150. For example, the first core network element determines, through local uplink history records, that the first core network element to which the terminal device accesses is different from the second core network element that sends the first connection message, thereby determining that the terminal device accesses the core network via a relay.

[0534] Step S1240: The first core network element sends a second connection transfer request message to the second core network element.

[0535] Correspondingly, the second core network element receives a second connection transfer request message from the first core network element. Compared to the first connection transfer request message, the second connection transfer request message may also include a relay paging indication message, which indicates that paging should be initiated to the terminal device via relay transmission. Upon receiving the relay paging indication message, the second core network element executes step S1250.

[0536] Step S1250: The second core network element determines identification information of the second access network device and the service request.

[0537] Step S1260: The second core network element sends a first paging request message to the second access network device.

[0538] Correspondingly, the second access network device receives a first paging request message from the second core network element. The first paging request message may refer to the description of step S1160.

[0539] Step S1270: The second access network device determines the first access network device and path indication information.

[0540] Step S1280: The second access network device sends a first paging request message through the first relay transmission path.

[0541] Correspondingly, the first access network device receives the first paging request message through the first relay transmission path.

[0542] Step S1290: The first access network device initiates paging to the terminal device.

[0543] When the first access network device successfully initiates paging to the terminal device, step S1295 is executed, and the first access network device sends a paging success notification message through the first relay transmission path.

[0544] Steps S1250 to S1295 can refer to the descriptions in steps S1150 to S1195, which will not be elaborated herein.

[0545] According to step S1170 in Example 7 and step S1270 in Example 8, the second access network device needs to determine the first access network device and the first relay transmission path when requesting an uplink service, so as to send the first paging request message to the first access network device, thereby realizing the downlink service request in the scenario where the connection between the first access network device and the first core network element is limited. Examples 9 to 12 illustrate the process of the second access network device determining the first access network device and the first relay transmission path, wherein Examples 9 and 10 illustrate determining the first access network device and path indication information through synchronized log information, and Examples 11 and 12 illustrate determining the path indication information through a secondary triggering consensus algorithm and routing process.

[0546] Example 9:

[0547] Figure 13 shows the interaction process of communication method 1300. In communication method 1300, the second access network device is the leader node of the consensus group. Compared with embodiment 7 and embodiment 8, embodiment 9 has additional steps S1365, S1366, and S1367.

[0548] Step S1365: The second access network device records the mapping relationship between the access network device and the uplink service request in log information.

[0549] In other words, the leader node records the mapping relationship between the access network device and the uplink service request in the log information. For example, when the terminal device initiates the first uplink service request, it accesses the access network device A, and when the terminal device initiates the second uplink service request, it accesses the access network device B. The second access network device (leader node) can record the mapping relationship between the first uplink service request and the access network device A, and the second uplink service request and the access network device B in the log information. Furthermore, in step S1370 (or step S1170 in Example 7, step S1270 in Example 8), the second access network device can determine the first access network device corresponding to the uplink service request based on the identification information of the uplink service request in the first paging request message.

[0550] Optionally, the above mapping relationship may also include the relay transmission path or path indication information used when requesting the uplink service. Furthermore, in step S1370 (or step S1170 in embodiment 7, step S1270 in embodiment 8), the second access network device may directly send the first paging indication message via the relay transmission path.

[0551] Step S1366: The second access network device synchronizes the log information to the third access network device.

[0552] Step S1367: The second access network device synchronizes the log information to the first access network device.

[0553] It should be understood that, in the case where the log information does not include path indication information or the first relay transmission path, the second access network device acts as the leader node, and by synchronizing the log information to other nodes in the consensus group, the other nodes can initiate a search request to the second access network device (leader node) based on the mapping relationship between the access network device and the uplink service request in the log information, for searching for the path indication information or the first relay transmission path. In the case where the log information includes path indication information or the first relay transmission path, the other nodes in the consensus group can directly forward the first paging request message based on the path indication information or the first relay transmission path.

[0554] This application does not limit the method of log synchronization. It can be that it starts a round of consensus algorithm and determines by voting whether each access network device in the consensus group needs to synchronize log information.

[0555] Step S1360 , step S1370 , step S1380 , step S1390 , and step S1395 in the communication method 1300 may refer to the description of step S1160 , step S1170 , step S1180 , step S1190 , and step S1195 in the communication method 1100 , respectively, and will not be described in detail herein.

[0556] Example 10:

[0557] Example 9 describes the case where the second access network device serves as the leader node, and Example 10 describes the case where the third access network device serves as the leader node. It is worth noting that the case where the first access network device serves as the leader node can refer to Example 10, and this article will not elaborate on this case.

[0558] Figure 14 shows the interaction process of the communication method 1400. In this case, the third access network device or any relay access network device is the leader node. Unlike embodiments 7 and 8, embodiment 10 includes steps S1465, S1466, and S1467.

[0559] Step S1465: The third access network device records the mapping relationship between the access network device and the uplink service request in a log message.

[0560] The specific solution of step S1465 can refer to the description of step S1365.

[0561] Step S1466: The third access network device synchronizes log information to the second access network device.

[0562] Furthermore, the second access network device can execute step S1470 based on the synchronized log information to determine the first access network device and the path indication information. For example, when the log information only includes the mapping relationship between the access network device and the uplink service request, the second access network device can determine the first access network device based on the identification information of the uplink service request included in the first paging request message, and request the third access network device to search for the path indication information or the first relay transmission path used in the uplink service request process based on the identification information of the uplink service request. For another example, when the log information includes path indication information or the first relay transmission path, the second access network device can execute step S1480 to send the first paging request message through the first relay transmission path.

[0563] Step S1467: The third access network device synchronizes log information with the first access network device.

[0564] Step S1460 , step S1470 , step S1480 , step S1490 , and step S1495 in the communication method 1400 may refer to the description of step S1160 , step S1170 , step S1180 , step S1190 , and step S1195 in the communication method 1100 , respectively, and will not be described in detail herein.

[0565] When the first access network device serves as the leader node, the first access network device performs the same steps as the third access network device in communication method 1400 and synchronizes log information to the second access network device. This application does not elaborate on this process.

[0566] However, the local uplink history may not contain path indication information, or the routing information of the first access network device may have expired. In this case, the access network device acting as the leader node cannot determine the first relay transmission path, which in turn causes the second access network device to be unable to send the first paging request message via the first relay transmission path. Therefore, Examples 11 and 12 provide technical solutions to the above-mentioned problems, namely, re-determining the first relay transmission path using the consensus algorithm described in Examples 4 to 6. Examples 11 and 12 respectively describe the scenarios where the second access network device acts as the leader node and the third access network device acts as the leader node.

[0567] Optionally, if there is no consensus group and leader node at this time, the process of establishing a consensus group and electing a leader node as shown in Examples 2 and 3 can be retriggered.

[0568] Example 11:

[0569] Figure 15 illustrates the interaction flow of communication method 1500, wherein communication method 1500 primarily determines path indication information through steps S1571 to S1578. Steps S1571 to S1578 share the same principles as steps S1013 to S1018 in Example 6, in which the second access network device, acting as the leader node, determines the first relay transmission path or path indication information.

[0570] Step S1571: The second access network device sends a connection status request message to the third access network device.

[0571] Correspondingly, the third access network device receives a connection status feedback message from the second access network device.

[0572] Step S1572: The second access network device receives a connection status feedback message from the third access network device.

[0573] Correspondingly, the third access network device sends a connection status feedback message to the second access network device.

[0574] Step S1575: The second access network device sends a connection status request message.

[0575] Correspondingly, the first access network device receives the connection status request message.

[0576] Step S1576: The second access network device receives a connection status feedback message.

[0577] Correspondingly, the first access network device sends a connection status feedback message.

[0578] Steps S1571 to S1576 may refer to the description of steps S1013 to S1016 in Example 6, or refer to the description of steps S811, S812, S815, and S816 in Example 4. The connection status request message and the connection status feedback message may refer to the description in Example 4.

[0579] Step S1578: The second access network device determines path indication information.

[0580] Step S1578 may refer to the description of step S1018 in Example 6 or step S918 in Example 5.

[0581] Steps S1560, S1570, S1580, S1590, and S1595 in the communication method 1500 may refer to the descriptions of S1160, S1170, S1180, S1190, and S1195 in the communication method 1100, respectively, and will not be described in detail herein.

[0582] Example 12:

[0583] Figure 16 illustrates the interaction flow of communication method 1600, wherein communication method 1600 primarily determines path indication information through steps S1670 through S1679. Steps S1671 through S1679 operate on the same principles as steps S911 through S918 in Example 5: In both cases, the third access network device, acting as the leader node, determines the first relay transmission path or path indication information. In method 1600, the third access network device transmits the first relay transmission path or path indication information to the second access network device.

[0584] As shown in Figure 16, in some embodiments of the present application, the second access network device may determine the first access network device in step S1670, for example, based on the log information described above. Furthermore, in step S1671, the second access network device, acting as the leader node, may request path indication information, or the first relay transmission path, and ultimately, in step S1678, receive a path information response message including the path indication information.

[0585] Step S1671: The second access network device sends a path information request message.

[0586] Correspondingly, the third access network device receives a path information request message. The path information request message is used to instruct the third access network device as the leader node to determine path indication information. Optionally, the path information request message may include identification information of the first access network device or identification information of the terminal device.

[0587] Step S1672: The third access network device sends a connection status request message to the second access network device.

[0588] Correspondingly, the second access network device receives a connection status request message from the third access network device.

[0589] Step S1673: The third access network device receives a connection status feedback message from the second access network device.

[0590] Correspondingly, the second access network device sends a connection status feedback message to the third access network device.

[0591] Step S1675: The third access network device sends a connection status request message to the first access network device.

[0592] Correspondingly, the first access network device receives a connection status request message from the third access network device.

[0593] Step S1676: The third access network device receives a connection status feedback message from the first access network device.

[0594] Correspondingly, the first access network device sends a connection status feedback message to the third access network device.

[0595] Steps S1672 to S1676 may refer to the description of steps S913 to S916 in Example 5, or refer to the description of steps S811, S812, S815, and S816 in Example 4. The connection status request message and the connection status feedback message may refer to the description in Example 4.

[0596] In step S1678, the third access network device sends a path information response message to the second access network device. The path information response message includes path indication information determined by the third access network device according to the connection status feedback message, for example, the path indication information is determined by step S918 in embodiment 5.

[0597] Step S1679: The second access network device determines path indication information.

[0598] Steps S1660, S1670, S1680, S1690, and S1695 in the communication method 1600 may refer to the descriptions of S1160, S1170, S1180, S1190, and S1195 in the communication method 1100, respectively, and will not be described in detail herein.

[0599] In other embodiments of the present application (not shown in FIG16 ), when the routing information of the first access network device expires, the second access network device may only be able to obtain the identification information of the paging terminal device through the first paging request message in step S1660, but cannot determine the first access network device. In the above case, the second access network device can send a path information request message to the third access network device serving as the leader node through step S1671. The path information request message can be used not only to request the leader node to query the path indication information, but also to request to query the first access network device. Alternatively, the second access network device sends an access network device query request message to the third access network device serving as the leader node to request to query the first access network device. In the above case, step S1670 shown in FIG16 is executed by the third access network device serving as the leader node after step S1671.

[0600] After receiving the path information request message in step S1671, the third access network device as the leader node determines the path indication information or the first relay transmission path through steps S1671 to S1676. In addition, after receiving the query request, the third access network device sends a connection status request message to the access network devices in the consensus group, requesting the access network devices in the consensus group to determine the location information of the terminal device based on the uplink history record, and feedback it to the third access network device through a connection status feedback message. In other words, the connection status feedback message also includes the location information of the terminal device determined by the access network devices in the consensus group, such as the IP address. The third access network device determines the first access network device based on the feedback location information of the terminal device through step S1670, and sends the path message response message including the path indication information and the first access network device to the second access network device through step S1678.

[0601] When the first access network device serves as the leader node, the first access network device performs the same steps as those performed by the third access network device in communication method 1600 and sends a path information response message to the second access network device. This application does not elaborate on this process.

[0602] In general, Examples 7 to 12 describe the process of requesting a downlink service when the connection between a first access network device and a first core network element is limited. Examples 7 and 8 describe the specific process of a downlink service request, Examples 9 and 10 describe how a second access network device determines the first access network device and / or path indication information based on log information during a downlink service request, and Examples 11 and 12 describe how path indication information is re-determined through a consensus algorithm during a downlink service request.

[0603] Furthermore, embodiments 1 to 12 realize the feasibility of making uplink service requests and downlink service requests when the connection between the first access network device and the first core network network element is limited, thereby improving the availability and network resilience of the core network.

[0604] Finally, the device embodiment of the embodiment of the present application is introduced.

[0605] To implement the various functions of the methods provided herein, communication devices, such as terminal devices or network devices, may include hardware structures and / or software modules, and implement the aforementioned functions in the form of hardware structures, software modules, or a combination of hardware structures and software modules. Whether a particular function is implemented 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.

[0606] Figure 17 is a schematic block diagram of a communication device 1700 according to an embodiment of the present application. Communication device 1700 includes a processor 1710 and a communication interface 1720, which may be interconnected via a bus 1730. Communication device 1700 may be a communication device, such as a terminal device, an access network device, or a core network element, that executes communication methods 500 to 1600.

[0607] Optionally, the communication device 1700 may further include a memory 1740. The memory 1740 includes, but is not limited to, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM), or portable read-only memory (CD-ROM), and is used to store relevant instructions and data.

[0608] The processor 1710 may be one or more central processing units (CPUs). In the case where the processor 1710 is a CPU, the CPU may be a single-core CPU or a multi-core CPU.

[0609] When the communication apparatus 1700 is a terminal device, illustratively, the communication apparatus 1700 is configured to perform the following operations: sending a first service request message.

[0610] When the communication apparatus 1700 is a first access network device, illustratively, the communication apparatus 1700 is configured to perform the following operations: sending a first connection message through a first relay transmission path.

[0611] When the communication apparatus 1700 is a second access network device, illustratively, the communication apparatus 1700 is configured to perform the following operations: sending a first connection message to a second core network element.

[0612] When the communication device 1700 is a second core network element, illustratively, the communication device 1700 is used to perform the following operations: determine whether the second core network element provides services for the terminal device.

[0613] When the communication device 1700 is a first core network element, illustratively, the communication device 1700 is configured to perform the following operations: receive a first connection message, and send a first connection response message.

[0614] When the communication device 1700 is a terminal device, an access network device, or a core network element, it will be responsible for executing the methods or steps related to the terminal device, access network device, or core network element in the above method embodiments.

[0615] The above description is merely exemplary. For details, please refer to the contents of the above method embodiments. The implementation of each operation in FIG17 may also correspond to the corresponding description of the method embodiments shown in FIG5 to FIG16.

[0616] Figure 18 is a schematic block diagram of a communication device 1800 according to an embodiment of the present application. Communication device 1800 may be a terminal device, access network device, or core network element, or may be a chip or module within such a device, configured to implement the methods described in the above embodiments. Communication device 1800 includes a transceiver unit 1810 and a processing unit 1820. The following provides an exemplary description of transceiver unit 1810 and processing unit 1820.

[0617] Transceiver unit 1810 may include a transmitting unit and a receiving unit. The transmitting unit is configured to execute a transmitting operation of the communication device, and the receiving unit is configured to execute a receiving operation of the communication device. For ease of description, this embodiment of the application combines the transmitting unit and the receiving unit into a single transceiver unit. This is described here as a unified description and will not be repeated later.

[0618] When the communication apparatus 1800 is a terminal device, illustratively, the transceiver unit 1810 is configured to perform the following operations: sending a first service request message.

[0619] When the communication apparatus 1800 is a first access network device, illustratively, the transceiver unit 1810 is configured to perform the following operations: sending a first connection message through a first relay transmission path.

[0620] When the communication apparatus 1800 is a second access network device, illustratively, the transceiver unit 1810 is configured to perform the following operations: sending a first connection message to a second core network element.

[0621] When the communication device 1800 is a second core network element, illustratively, the processing unit 1820 is configured to perform the following operations: determining whether the second core network element provides services for the terminal device.

[0622] When the communication device 1800 is a first core network element, illustratively, the transceiver unit 1810 is configured to perform the following operations: receive a first connection message, and send a first connection response message.

[0623] When the communication device 1800 is a terminal device, an access network device, or a core network element, it will be responsible for executing the methods or steps related to the terminal device, access network device, or core network element in the above method embodiments.

[0624] Optionally, the communication device 1800 further includes a storage unit 1830, which is used to store a program or code for executing the aforementioned method.

[0625] The device embodiments shown in Figures 17 and 18 are used to implement the contents described in Figures 5 to 16. The specific execution steps and methods of the devices shown in Figures 17 and 18 can refer to the contents described in the above method embodiments.

[0626] Figure 19 is a schematic block diagram of a communication device 1900 according to an embodiment of the present application. Communication device 1900 is used to implement the functions of a terminal device, access network device, or core network element. Communication device 1900 may be a chip in a terminal device, access network device, or core network element.

[0627] Communication device 1900 includes an input / output interface 1920 and a processor 1910. Input / output interface 1920 may be an input / output circuit. Processor 1910 may be a signal processor, a chip, or other integrated circuit capable of implementing the method of the present application. Input / output interface 1920 is used for inputting or outputting signals or data.

[0628] For example, when the communication apparatus 1900 is a terminal device, illustratively, the input / output interface 1920 is configured to perform the following operations: sending a first service request message.

[0629] When the communication apparatus 1900 is a first access network device, illustratively, the input / output interface 1920 is configured to perform the following operations: sending a first connection message through a first relay transmission path.

[0630] When the communication apparatus 1900 is a second access network device, illustratively, the input / output interface 1920 is configured to perform the following operations: sending a first connection message to a second core network element.

[0631] When the communication device 1900 is a second core network element, illustratively, the processor 1910 is configured to perform the following operations: determining whether the second core network element provides services for the terminal device.

[0632] When the communication device 1900 is a first core network element, illustratively, the input / output interface 1920 is configured to perform the following operations: receive a first connection message, and send a first connection response message.

[0633] In one possible implementation, the processor 1910 implements the functions implemented by the terminal device, access network device or core network element by executing instructions stored in the memory.

[0634] Optionally, the communication device 1900 further includes a memory.

[0635] Optionally, the processor and memory are integrated together.

[0636] Optionally, the memory is outside the communication device 1900 .

[0637] In one possible implementation, the processor 1910 may be a logic circuit that inputs / outputs messages or signals through the input / output interface 1920. The logic circuit may be a signal processor, a chip, or other integrated circuit that can implement the method of the embodiment of the present application.

[0638] The above description of the communication device 1900 is only an exemplary description. The communication device 1900 can be used to execute the method described in the above embodiment. For specific content, please refer to the description of the above method embodiment, which will not be repeated here.

[0639] The present application also provides a chip, including a processor, for calling and executing instructions stored in a memory from the memory, so that a communication device equipped with the chip executes the methods in the above examples.

[0640] The present application also provides a chip, comprising: an input interface, an output interface, and a processor, wherein the input interface, the output interface, and the processor are connected via an internal connection path, and the processor is configured to execute code in a memory. When the code is executed, the processor is configured to execute the methods in the above examples. Optionally, the chip also includes a memory, which is configured to store computer programs or code.

[0641] The present application also provides a processor for coupling with a memory, and for executing the methods and functions involving a network device or a terminal device in any of the above embodiments.

[0642] The present application provides a computer program product comprising instructions. When the computer program product is run on a computer, the method of the aforementioned embodiment is implemented.

[0643] The present application also provides a computer program. When the computer program is executed in a computer, the method of the aforementioned embodiment is implemented.

[0644] The present application also provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a computer, the method described in the above embodiment is implemented.

[0645] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0646] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0647] In the several embodiments provided in this application, the disclosed systems, devices, and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of units is only a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0648] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the technical solutions of the embodiments of the present application.

[0649] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0650] If the function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the embodiment of the present application, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of each method embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a ROM, a RAM, a magnetic disk, or an optical disk.

[0651] The above description is merely a specific embodiment of the present application, but the scope of protection of the embodiments of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the embodiments of the present application should be included in the scope of protection of the embodiments of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A communication method, characterized in that: include: The first access network device sends a first connection message through a first relay transmission path, where the first connection message is used to instruct the first core network network element to provide services for the terminal device. The first relay transmission path includes a message transmission path between the first access network device and the second access network device, where the second access network device is connected to the first core network network element, or the second access network device is connected to the second core network network element, where the second core network element is used to determine the first core network network element.

2. The method according to claim 1, characterized in that There is limited connectivity between the first access network device and the first core network element.

3. The method according to claim 1 or 2, characterized in that: Before the first access network device sends the first connection message, the method further includes: The first access network device receives a first service request message from the terminal device, where the first service request message is used to indicate a request for the first core network element to provide a service to the terminal device.

4. The method according to any one of claims 1 to 3, characterized in that include: The first connection message includes identification information of the terminal device, identification information of the first access network device, and path indication information, and the path indication information is used to indicate the first relay transmission path.

5. The method according to claim 4, characterized in that The first connection message also includes identification information of the service request initiated by the terminal device.

6. The method according to any one of claims 1 to 5, characterized in that The method further comprises: The first access network device receives a first connection response message through the first relay transmission path, wherein the first connection response message includes identification information of the terminal device, identification information of the first access network device, and at least one of path indication information, and the path indication information is used to indicate the first relay transmission path.

7. The method according to any one of claims 1 to 6, characterized in that Before the first access network device sends the first connection message, the method further includes: The first access network device sends a first relay service request message, where the first relay service request message is used to indicate that the first access network device requests to send the first connection message by means of relay transmission; The first access network device receives a first relay service request response message, where the first relay service request response message includes path indication information, where the path indication information is used to indicate the first relay transmission path.

8. The method according to claim 7, characterized in that The method further comprises: The first access network device receives a connection status request message, where the connection status request message is used to request to determine a connection relationship between the first access network device and one or more access network devices; The first access network device sends a connection status feedback message, where the connection status feedback message includes a connection relationship between the first access network device and at least one access network device.

9. The method according to claim 8, characterized in that The connection status request message includes group identification information and / or connection attribute information of a first consensus group, the first consensus group includes multiple access network devices, the multiple access network devices include the first access network device and the at least one access network device, and the connection attribute information includes at least one of connection bandwidth, delay, connection type, jitter, time taken to restore the connection and whether there is security protection.

10. The method according to any one of claims 7 to 9, characterized in that The first relay service request message includes identification information of the terminal device.

11. The method according to any one of claims 1 to 6, characterized in that Before the first access network device sends the first connection message, the method further includes: The first access network device determines the first relay transmission path according to a connection relationship between multiple access network devices included in a first consensus group, and the multiple access network devices include the first access network device and the second access network device.

12. The method according to claim 11, characterized in that The method further comprises: The first access network device sends a connection status request message to an access network device other than the first access network device among the multiple access network devices, where the connection status request message is used to request to determine a connection relationship between the multiple access network devices; The first access network device receives a connection status feedback message, wherein the connection status feedback message includes connection relationship.

13. The method according to any one of claims 1 to 12, characterized in that After the first access network device sends the first connection message, the method further includes: The first access network device receives a first paging request message through the first relay transmission path, where the first paging request message is used to request to initiate paging to the terminal device.

14. The method according to claim 13, characterized in that The first paging request message includes identification information of the terminal device.

15. The method according to claim 13 or 14, characterized in that In the case where the first access network device successfully initiates paging to the terminal device, the method further includes: The first access network device sends a paging success notification message through the first relay transmission path, and the paging success notification message is used to notify the first core network network element to instruct the terminal device to perform a paging action.

16. The method according to any one of claims 1 to 15, characterized in that The second access network device is connected to the first core network element or the second core network element through a non-terrestrial communication network NTN.

17. A communication method, characterized in that: include: The second access network device receives a first paging request message from the first core network network element or the second core network network element, where the first paging request message is used to request the first access network device to page the terminal device so that the first core network network element provides services to the terminal device, the second access network device is connected to the first core network network element, or the second access network device is connected to the second core network network element, and the second core network network element is used to forward the first paging request message sent by the first core network network element; The second access network device sends the first paging request message through a first relay transmission path, where the first relay transmission path includes a message transmission path between the first access network device and the second access network device.

18. The method according to claim 17, characterized in that There is limited connectivity between the first access network device and the first core network element.

19. The method according to claim 17 or 18, characterized in that The method further comprises: The second access network device determines the first access network device corresponding to the first service request message based on the log information, the first service request message is used to indicate a request for the first core network element to provide service to the terminal device, the log information includes a correspondence between at least one access network device and at least one service request message, and each of the at least one access network device receives a corresponding service request message from the terminal device.

20. The method according to claim 19, characterized in that The log information also includes path indication information, and the path indication information is used to indicate the first relay transmission path.

21. The method according to claim 19 or 20, characterized in that The method further comprises: The second access network device receives the log information from an access network device in a first consensus group, where the first consensus group includes a plurality of access network devices, and the plurality of access network devices include the first access network device and the second access network device.

22. The method according to claim 17 or 18, characterized in that The method further comprises: The second access network device receives path indication information from an access network device in a first consensus group, where the path indication information is used to indicate the first relay transmission path. The first consensus group includes multiple access network devices, and the multiple access network devices include the first access network device and the second access network device.

23. The method according to claim 22, characterized in that The method further comprises: The second access network device sends a path request message, where the path request message is used to determine the first relay transmission path; The second access network device receiving the path indication information from the access network device in the first consensus group includes: The second access network device receives a path request response message from an access network device in the first consensus group, where the path request response message includes the path indication information.

24. A communication device, characterized in that: include: A processor, wherein the processor is configured to execute a program or an instruction so that the apparatus executes the method according to any one of claims 1 to 16.

25. A communication device, characterized in that: include: A processor, wherein the processor is configured to execute a program or an instruction so that the apparatus executes the method according to any one of claims 17 to 23.

26. A communication system, characterized in that: Includes the communication device as described in claim 24 and the communication device as described in claim 25.

27. The communication system according to claim 26, characterized in that The communication system also includes a first core network element and / or a second core network element and a terminal device as described in any one of claims 1 to 23.

28. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed on a computer, the computer is caused to execute the method according to any one of claims 1 to 16, or the method according to any one of claims 17 to 23.

29. A computer program product, characterized in that The method comprises a computer program code, which, when executed, implements the method according to any one of claims 1 to 16, or the method according to any one of claims 17 to 23.

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