Communication method and communication device

Abstract

The invention provides a communication method and a communication device, and the method comprises the steps: releasing a first terminal device to a non-connection state, the first terminal device being a terminal device managed by a mobile relay node, the mobile relay node being connected with a first host node; first information is sent to a first network element, the first information indicates to determine whether the first network element and a second host node are reachable, the second host node is a host node to be connected with the mobile relay node, and indication information indicating to determine whether the first network element and the second host node are reachable is sent to the first network element. According to the embodiment of the invention, the first network element can page the first terminal device in time under the condition that the first network element is determined to be inaccessible to the second host node.

Description

Technical Field

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

[0002] The fifth generation of mobile communication (5G) introduces the integrated access and backhaul (IAB) technology to reduce fiber optic deployment.

[0003] In an IAB communication network, an IAB node can provide wireless access services for a terminal device. For example, the service data of the terminal device can be transmitted by the IAB node to an IAB donor through a wireless backhaul link, where the IAB donor can be connected to a core network element serving the terminal device.

[0004] Among them, the IAB node can be deployed on a movable carrier such as a vehicle. At this time, the IAB node can be called a mobile relay node. When the IAB node is a mobile relay node, the tracking area code (TAC) list or RAN area code (RANAC) list broadcast by the IAB-DU is related to the current geographical location of the IAB node, and thus may change. The TAC list or RANAC list is used for the location management of the UE. To save signaling overhead, it can be considered that the TAC or RANAC broadcast by the IAB-DU does not change. In the case where the TAC / RANAC broadcast by the IAB-DU does not change, taking the TAC as an example, there may be a situation where the access management network element of an idle state terminal resident in the cell under the IAB-DU cannot page the terminal. For example, if the IAB node moves to a far place and the TAC is not changed at this time, it may cause the access management network element of the idle state terminal to lose connection with the IAB donor corresponding to the cell where the terminal resides, and further cause the terminal to be unable to be paged, resulting in the terminal losing connection with the network. Therefore, when the IAB node moves, how to timely discover and page the terminal device managed by the IAB node is a problem that needs to be considered. Summary of the Invention

[0005] This application provides a communication method and a communication device, which can timely discover and page the terminal device managed by the mobile relay node.

[0006] In a first aspect, a communication method is provided. This method can be executed by a first donor node, or can also be executed by a component (such as a chip or a circuit) of the first donor node, and this is not limited. For the sake of convenience of description, the following takes the execution by the first donor node as an example for illustration.

[0007] The method includes: releasing a first terminal device to a disconnected state, where the first terminal device is a terminal device managed by a mobile relay node, and the mobile relay node has a connection with a first host node; sending first information to a first network element, where the first information indicates determining whether the first network element is reachable from a second host node, and the second host node is a host node to which the mobile relay node is to be connected.

[0008] Based on the above solution, by sending indication information to the first network element to determine whether the first network element is reachable from the second host node, the first network element can page the first terminal device in a timely manner when it determines that it is not reachable from the second host node.

[0009] In combination with the first aspect, in some implementation manners of the first aspect, the first network element includes an access and mobility management network element corresponding to the first terminal device or an access network device to which the first terminal device was last connected before entering the disconnected state.

[0010] In combination with the first aspect, in some implementation manners of the first aspect, after releasing the first terminal device to the disconnected state, the identifier of the access and mobility management network element corresponding to the first terminal device is saved.

[0011] In combination with the first aspect, in some implementation manners of the first aspect, the first information includes identification information of the second host node.

[0012] In combination with the first aspect, in some implementation manners of the first aspect, if the first network element is not reachable from the second host node, a paging message from the first network element for paging the first terminal device is received; and the paging message is sent to the first terminal device.

[0013] Based on the above solution, when the first network element is not reachable from the second host node, the first network element can page the first terminal device, so that the first terminal device can be discovered in a timely manner.

[0014] In combination with the first aspect, in some implementation manners of the first aspect, second information is sent to the second host node, where the second information includes the identifier of the access and mobility management network element corresponding to each of at least one second terminal device and / or the identifier of the access network device to which each of the second terminal devices was last connected before entering the disconnected state; where the second terminal device is a terminal device in a cell managed by the mobile relay node, and the second terminal device is released to the disconnected state by a third host node, and the third host node includes a host node to which the mobile relay node was connected before connecting to the first host node.

[0015] Based on the above solution, by sending the second information to the second host node, when the mobile relay node moves to the target host node, the second host node can interact with the target host node about the second information to discover the second terminal device in the idle state.

[0016] In combination with the first aspect, in some implementation manners of the first aspect, send third information to a second network element, where the third information indicates determining whether the second network element is reachable from the second host node, and the second network element is an access and mobility management network element corresponding to the second terminal device, or an access network device to which the second terminal device was last connected before entering the disconnected state.

[0017] Based on the above solution, by sending indication information indicating determining whether the second network element is reachable from the second host node to the second network element, the second network element can be enabled to page the second terminal device in a timely manner when it is determined that the second network element is unreachable from the second host node.

[0018] In combination with the first aspect, in some implementation manners of the first aspect, the third information includes identification information of the second host node.

[0019] In combination with the first aspect, in some implementation manners of the first aspect, if the second network element is unreachable from the second host node, receive a paging message from the second network element, where the paging message is used to page the second terminal device; and send the paging message to the second terminal device.

[0020] In combination with the first aspect, in some implementation manners of the first aspect, save the identification of the access and mobility management network element corresponding to the second terminal device, and / or the identification of the access network device to which the second terminal device was last connected before entering the disconnected state.

[0021] In a second aspect, a communication method is provided. In this method, a first host node sends first information indicating determining whether the second host node is reachable from a first network element to the second host node. This method can be executed by the first host node, or can also be executed by a component (such as a chip or a circuit) of the first host node, and this is not limited. For ease of description, the following takes the execution by the first host node as an example for illustration.

[0022] The method includes: releasing a first terminal device to the disconnected state, where the first terminal device is a terminal device managed by a mobile relay node, and the mobile relay node is connected to the first host node; and sending first information to the second host node, where the first information indicates determining whether the second host node is reachable from the first network element, and the second host node is a host node to which the mobile relay node is to be connected.

[0023] Based on the above solution, by sending indication information for determining whether the first network element is reachable from the second host node to the second host node, it can be ensured that when the second host node determines that it is not reachable from the first network element, it can page the first terminal device in a timely manner.

[0024] In combination with the second aspect, in some implementation manners of the second aspect, the first network element includes the access and mobility management network element corresponding to the first terminal device, or the access network device to which the first terminal device was last connected before entering the disconnected state.

[0025] In combination with the second aspect, in some implementation manners of the second aspect, if the first network element is the access and mobility management network element corresponding to the first terminal device, after releasing the first terminal device to the disconnected state, the identifier of the access and mobility management network element corresponding to the first terminal device is saved.

[0026] In combination with the second aspect, in some implementation manners of the second aspect, the first information includes the identifier information of the access and mobility management network element corresponding to the first terminal device.

[0027] In combination with the second aspect, in some implementation manners of the second aspect, if the second host node is not reachable from the first network element, a first request message is received from the second host node, where the first request message is used to request paging the first terminal device; a first indication information is sent to the access and mobility management network element corresponding to the first terminal device according to the first request message, and the first indication information indicates paging the first terminal device.

[0028] Based on the above solution, when the first network element is not reachable from the second host node, a request message for paging the first terminal device can be initiated by the second host node, so as to page the first terminal device.

[0029] In combination with the second aspect, in some implementation manners of the second aspect, if the second host node is not reachable from the first network element, a paging message is sent to the first terminal device, where the paging message is used to page the first terminal device.

[0030] Based on the above solution, when the first network element is not reachable from the second host node, the first host node can page the first terminal device, so that the first terminal device can be discovered in a timely manner.

[0031] In combination with the second aspect, in some implementations of the second aspect, second information is sent to the second host node, where the second information includes the identifier of the access and mobility management network element corresponding to each second terminal device among at least one second terminal device, and / or the identifier of the access network device to which each second terminal device was last connected before entering the inactive state; wherein, the second terminal device is a terminal device in the cell managed by the mobile relay node, and the second terminal device is released by the third host node to the disconnected state, and the third host node includes the host node to which the mobile relay node was connected before being connected to the first host node.

[0032] Based on the above solution, by sending the second information to the second host node, in the case where the mobile relay node moves to the target host node, the second host node can interact with the target host node with the second information to discover the second terminal device in the idle state.

[0033] In combination with the second aspect, in some implementations of the second aspect, third information is sent to the second host node, where the third information indicates determining whether the second host node is reachable from the second network element, and the second network element is the access and mobility management network element corresponding to the second terminal device, or the access network device to which the second terminal device was last connected before entering the disconnected state.

[0034] Based on the above solution, by sending indication information for indicating determining whether the second network element is reachable from the second host node to the second host node, in the case where the second host node determines that it is not reachable from the second network element, the second host node can page the second terminal device in a timely manner.

[0035] In combination with the second aspect, in some implementations of the second aspect, when the second network element is the access and mobility management network element corresponding to the second terminal device, the third information includes the identifier information of the access and mobility management network element corresponding to the second terminal device.

[0036] In combination with the second aspect, in some implementations of the second aspect, if the second host node is not reachable from the second network element, a second request message is received from the second host node, where the second request message is used to request paging the second terminal device; and second indication information for indicating paging the second terminal device is sent to the access and mobility management network element corresponding to the second terminal device according to the second request message.

[0037] Based on the above solution, in the case where the second network element is not reachable from the second host node, a request message for paging the second terminal device can be initiated by the second host node, so as to page the second terminal device.

[0038] In combination with the second aspect, in some implementations of the second aspect, if the second host node is unreachable from the second network element, a second paging message is sent to the second terminal device, and the second paging message is used to page the second terminal device.

[0039] Based on the above solution, in the case where the second network element is unreachable from the second host node, the first host node can page the second terminal device, so that the second terminal device can be discovered in a timely manner.

[0040] In combination with the second aspect, in some implementations of the second aspect, the identifier of the access and mobility management network element corresponding to the second terminal device, and / or the identifier of the access network device to which the second terminal device was last connected before entering the disconnected state are saved.

[0041] In a third aspect, a communication method is provided. This method can be executed by a first network element, or alternatively, can be executed by a component (such as a chip or a circuit) of the first network element, and this is not limited. For ease of description, the following will illustrate by taking the execution by the first network element as an example.

[0042] The method includes: receiving first information from a first host node; determining whether the first network element is reachable from a second host node according to the first information; paging a first terminal device in the case where it is determined that the first network element is unreachable from the second host node; where the first terminal device is a terminal device managed by a mobile relay node, the mobile relay node has a connection with the first host node, the first terminal device is released to the disconnected state by the first host node, and the second host node is the host node to which the mobile relay node is to be connected.

[0043] Based on the above solution, by receiving indication information from the first host node to determine whether the first network element is reachable from the second host node, the first network element can page the first terminal device in a timely manner in the case where it is determined that it is unreachable from the second host node.

[0044] In combination with the third aspect, in some implementations of the third aspect, the first network element includes any one of the following: the access and mobility management network element corresponding to the first terminal device, the access network device to which the first terminal device was last connected before entering the disconnected state.

[0045] In combination with the third aspect, in some implementations of the third aspect, the first information includes the identifier information of the second host node.

[0046] In combination with the third aspect, in some implementations of the third aspect, a paging message is sent to the first terminal device through the first host node, and the paging message is used to page the first terminal device.

[0047] Fourthly, a communication method is provided. This method can be executed by a second host node, or by a component (such as a chip or a circuit) of the second host node, which is not limited herein. For the sake of description, hereinafter, the case where it is executed by the second host node will be taken as an example for illustration.

[0048] The method includes: receiving first information from a first host node; determining whether the second host node is reachable from a first network element according to the first information; and paging a first terminal device when it is determined that the second host node is not reachable from the first network element; wherein the first terminal device is a terminal device managed by a mobile relay node, the mobile relay node is connected to the first host node, the first terminal device is released by the first host node to a disconnected state, and the second host node is a host node to which the mobile relay node is to be connected.

[0049] Based on the above solution, by receiving indication information for determining whether the first network element is reachable from the second host node from the first host node, the second host node can page the first terminal device in time when it is determined that the second host node is not reachable from the first network element.

[0050] In combination with the fourth aspect, in some implementation manners of the fourth aspect, the first network element includes an access and mobility management network element corresponding to the first terminal device, or an access network device to which the first terminal device was last connected before entering the disconnected state.

[0051] In combination with the fourth aspect, in some implementation manners of the fourth aspect, if the first network element is an access and mobility management network element corresponding to the first terminal device, the first information includes identification information of the access and mobility management network element corresponding to the first terminal device.

[0052] In combination with the fourth aspect, in some implementation manners of the fourth aspect, a first request message is sent to the first host node, and the first request message is used to request paging of the first terminal device.

[0053] In combination with the fourth aspect, in some implementation manners of the fourth aspect, second information is received from the first host node, and the second information includes an identification of an access and mobility management network element corresponding to each of at least one second terminal device, and / or an identification of an access network device to which each of the second terminal devices was last connected before entering the inactive state; wherein the second terminal device is a terminal device in a cell managed by the mobile relay node, the second terminal device is released by a third host node to a disconnected state, and the third host node includes a host node to which the mobile relay node was connected before being connected to the first host node.

[0054] In combination with the fourth aspect, in some implementations of the fourth aspect, receive third information from the first host node, where the third information indicates determining whether the second host node and the second network element are reachable, and the second network element is the access and mobility management network element corresponding to the second terminal device, or the access network device to which the second terminal device was last connected before entering the disconnected state; in the case where it is determined that the second host node and the second network element are unreachable, page the second terminal device.

[0055] In combination with the fourth aspect, in some implementations of the fourth aspect, when the second network element is the access and mobility management network element corresponding to the second terminal device, the third information includes the identification information of the access and mobility management network element corresponding to the second terminal device.

[0056] In combination with the fourth aspect, in some implementations of the fourth aspect, if the second host node and the second network element are unreachable, send a second request message to the first host node, where the second request message is used to request paging the second terminal device.

[0057] A fifth aspect provides a communication device. The device includes a processing unit and a transceiver unit. The processing unit is used to release a first terminal device to the disconnected state, where the first terminal device is a terminal device managed by a mobile relay node, and the mobile relay node is connected to the device; the transceiver unit is used to send first information to a first network element, where the first information indicates determining whether the first network element and a second host node are reachable, and the second host node is the host node to which the mobile relay node is to be connected.

[0058] In combination with the fifth aspect, in some implementations of the fifth aspect, the first network element includes the access and mobility management network element corresponding to the first terminal device or the access network device to which the first terminal device was last connected before entering the disconnected state.

[0059] In combination with the fifth aspect, in some implementations of the fifth aspect, after releasing the first terminal device to the disconnected state, the processing unit is further used to save the identification of the access and mobility management network element corresponding to the first terminal device.

[0060] In combination with the fifth aspect, in some implementations of the fifth aspect, the first information includes the identification information of the second host node.

[0061] In combination with the fifth aspect, in some implementations of the fifth aspect, if the first network element and the second host node are unreachable, the transceiver unit is further used to receive a paging message from the first network element, where the paging message is used to page the first terminal device; and send the paging message to the first terminal device.

[0062] In combination with the fifth aspect, in some implementations of the fifth aspect, the transceiver unit is further configured to send second information to the second host node, where the second information includes the identifier of the access and mobility management network element corresponding to each second terminal device among at least one second terminal device, and / or the identifier of the access network device to which each second terminal device was last connected before entering the disconnected state; wherein the second terminal device is a terminal device in the cell managed by the mobile relay node, and the second terminal device is released to the disconnected state by a third host node, and the third host node includes the host node to which the mobile relay node was connected before being connected to the apparatus.

[0063] In combination with the fifth aspect, in some implementations of the fifth aspect, the transceiver unit is further configured to send third information to a second network element, where the third information indicates determining whether the second network element is reachable from the second host node, and the second network element is the access and mobility management network element corresponding to the second terminal device, or the access network device to which the second terminal device was last connected before entering the disconnected state.

[0064] In combination with the fifth aspect, in some implementations of the fifth aspect, the third information includes the identifier information of the second host node.

[0065] In combination with the fifth aspect, in some implementations of the fifth aspect, if the second network element is not reachable from the second host node, the transceiver unit is further configured to: receive a paging message from the second network element, where the paging message is used to page the second terminal device; and send the paging message to the second terminal device.

[0066] In combination with the fifth aspect, in some implementations of the fifth aspect, the processing unit is further configured to save the identifier of the access and mobility management network element corresponding to the second terminal device, and / or the identifier of the access network device to which the second terminal device was last connected before entering the disconnected state.

[0067] In a sixth aspect, a communication apparatus is provided, the apparatus includes a transceiver unit and a processing unit, the processing unit is configured to release a first terminal device to the disconnected state, where the first terminal device is a terminal device managed by a mobile relay node, and the mobile relay node is connected to a first host node; the transceiver unit is configured to send first information to a second host node, where the first information indicates determining whether the second host node is reachable from a first network element, and the second host node is the host node to which the mobile relay node is to be connected.

[0068] In combination with the sixth aspect, in some implementations of the sixth aspect, the first network element includes the access and mobility management network element corresponding to the first terminal device, or the access network device to which the first terminal device was last connected before entering the disconnected state.

[0069] In combination with the sixth aspect, in some implementations of the sixth aspect, if the first network element is the access and mobility management network element corresponding to the first terminal device, after releasing the first terminal device to the disconnected state, the processing unit is further configured to save the identifier of the access and mobility management network element corresponding to the first terminal device.

[0070] In combination with the sixth aspect, in some implementations of the sixth aspect, the first information includes the identifier information of the access and mobility management network element corresponding to the first terminal device.

[0071] In combination with the sixth aspect, in some implementations of the sixth aspect, if the second host node is unreachable from the first network element, the transceiver unit is specifically configured to receive a first request message from the second host node, where the first request message is used to request paging the first terminal device; and send a first indication message to the access and mobility management network element corresponding to the first terminal device according to the first request message, where the first indication message indicates paging the first terminal device.

[0072] In combination with the sixth aspect, in some implementations of the sixth aspect, if the second host node is unreachable from the first network element, the transceiver unit is specifically configured to send a paging message to the first terminal device, where the paging message is used to page the first terminal device.

[0073] In combination with the sixth aspect, in some implementations of the sixth aspect, the transceiver unit is further configured to send second information to the second host node, where the second information includes the identifiers of the access and mobility management network elements corresponding to each of at least one second terminal device, and / or the identifier of the access network device to which each of the second terminal devices was last connected before entering the inactive state; where the second terminal device is a terminal device in the cell managed by the mobile relay node, and the second terminal device is released to the disconnected state by a third host node, and the third host node includes the host node to which the mobile relay node was connected before being connected to the first host node.

[0074] In combination with the sixth aspect, in some implementations of the sixth aspect, the transceiver unit is further configured to send third information to the second host node, where the third information indicates determining whether the second host node is reachable from a second network element, and the second network element is the access and mobility management network element corresponding to the second terminal device, or the access network device to which the second terminal device was last connected before entering the disconnected state.

[0075] In combination with the sixth aspect, in some implementations of the sixth aspect, when the second network element is the access and mobility management network element corresponding to the second terminal device, the third information includes the identifier information of the access and mobility management network element corresponding to the second terminal device.

[0076] In combination with the sixth aspect, in some implementations of the sixth aspect, if the second host node is unreachable from the second network element, the transceiver unit is further configured to: receive a second request message from the second host node, where the second request message is used to request paging the second terminal device; and send second indication information to the access and mobility management network element corresponding to the second terminal device according to the second request message, where the second indication information indicates paging the second terminal device.

[0077] In combination with the sixth aspect, in some implementations of the sixth aspect, if the second host node is unreachable from the second network element, the transceiver unit is further configured to send a second paging message to the second terminal device, where the second paging message is used to page the second terminal device.

[0078] In combination with the sixth aspect, in some implementations of the sixth aspect, the processing unit is further configured to save the identifier of the access and mobility management network element corresponding to the second terminal device, and / or the identifier of the access network device to which the second terminal device was last connected before entering the disconnected state.

[0079] A seventh aspect provides a communication device, which includes a transceiver unit and a processing unit. The transceiver unit is configured to receive first information from a first host node; the processing unit is configured to determine whether the first network element is reachable from the second host node according to the first information; in the case where it is determined that the first network element is unreachable from the second host node, the processing unit is further configured to page a first terminal device; where the first terminal device is a terminal device managed by a mobile relay node, the mobile relay node has a connection with the first host node, the first terminal device is released by the first host node to the disconnected state, and the second host node is the host node to which the mobile relay node is to be connected.

[0080] In combination with the seventh aspect, in some implementations of the seventh aspect, the first network element includes the access and mobility management network element corresponding to the first terminal device, or the access network device to which the first terminal device was last connected before entering the disconnected state.

[0081] In combination with the seventh aspect, in some implementations of the seventh aspect, the first information includes the identifier information of the second host node.

[0082] In combination with the seventh aspect, in some implementations of the seventh aspect, the transceiver unit is further configured to send a paging message to the first terminal device through the first host node, where the paging message is used to page the first terminal device.

[0083] In an eighth aspect, a communication device is provided. The device includes a transceiver unit and a processing unit. The transceiver unit is configured to receive first information from a first host node. The processing unit is configured to determine whether the second host node and a first network element are reachable based on the first information. In a case where it is determined that the second host node and the first network element are unreachable, the processing unit is further configured to page a first terminal device. Wherein, the first terminal device is a terminal device managed by a mobile relay node, the mobile relay node is connected to the first host node, the first terminal device is released by the first host node to a disconnected state, and the second host node is a host node to which the mobile relay node is to be connected.

[0084] In combination with the eighth aspect, in some implementation manners of the eighth aspect, the first network element includes an access and mobility management network element corresponding to the first terminal device, or an access network device to which the first terminal device was last connected before entering the disconnected state.

[0085] In combination with the eighth aspect, in some implementation manners of the eighth aspect, if the first network element is an access and mobility management network element corresponding to the first terminal device, the first information includes identification information of the access and mobility management network element corresponding to the first terminal device.

[0086] In combination with the eighth aspect, in some implementation manners of the eighth aspect, the transceiver unit is specifically configured to send a first request message to the first host node, and the first request message is used to request paging the first terminal device.

[0087] In combination with the eighth aspect, in some implementation manners of the eighth aspect, the transceiver unit is further configured to receive second information from the first host node. The second information includes identification of an access and mobility management network element corresponding to each of at least one second terminal device, and / or an identification of an access network device to which each of the second terminal devices was last connected before entering the inactive state. Wherein, the second terminal device is a terminal device in a cell managed by the mobile relay node, the second terminal device is released by a third host node to a disconnected state, and the third host node includes a host node to which the mobile relay node was connected before being connected to the first host node.

[0088] In combination with the eighth aspect, in some implementation manners of the eighth aspect, the transceiver unit is further configured to receive third information from the first host node. The third information indicates determining whether the second host node and a second network element are reachable. The second network element is an access and mobility management network element corresponding to the second terminal device, or an access network device to which the second terminal device was last connected before entering the disconnected state. In a case where it is determined that the second host node and the second network element are unreachable, the processing unit is further configured to page the second terminal device.

[0089] In combination with the eighth aspect, in some implementations of the eighth aspect, when the second network element is the access and mobility management network element corresponding to the second terminal device, the third information includes the identification information of the access and mobility management network element corresponding to the second terminal device.

[0090] In combination with the eighth aspect, in some implementations of the eighth aspect, if the second host node is unreachable from the second network element, the transceiver unit is further configured to send a second request message to the first host node, where the second request message is used to request paging of the second terminal device.

[0091] A ninth aspect provides a communication device, which is configured to execute the method in any one of the possible implementations of the first aspect to the fourth aspect. Specifically, the device may include units and / or modules for executing the method in any one of the possible implementations of the first aspect to the fourth aspect, such as a processing unit and / or a transceiver unit.

[0092] In one implementation, the device is a communication device (such as a first host node, a first network element, or a second host node). When the device is a communication device, the communication unit may be a transceiver, or an input / output interface; the processing unit may be at least one processor. Optionally, the transceiver may be a transceiver circuit. Optionally, the input / output interface may be an input / output circuit.

[0093] In another implementation, the device is a chip, a chip system, or a circuit for a communication device (such as a first host node, a first network element, or a second host node). When the device is a chip, a chip system, or a circuit for a communication device, the communication unit may be an input / output interface, an interface circuit, an output circuit, an input circuit, a pin, or a related circuit, etc. on the chip, the chip system, or the circuit; the processing unit may be at least one processor, a processing circuit, or a logic circuit, etc.

[0094] A tenth aspect provides a communication device, which includes: at least one processor, configured to execute a computer program or instruction stored in a memory to execute the method in any one of the possible implementations of the first aspect to the fourth aspect.

[0095] Optionally, the device further includes a memory for storing a computer program or instruction. Optionally, the device further includes a communication interface, and the processor reads the computer program or instruction stored in the memory through the communication interface.

[0096] In one implementation, the device is a communication device (such as a first host node, a first network element, or a second host node).

[0097] An eleventh aspect provides a processor, configured to execute the method in any one of the possible implementations of the first aspect to the fourth aspect.

[0098] For operations such as sending and obtaining / receiving involved in the processor, if there is no special description, or if it does not conflict with its actual function or internal logic in the relevant description, it can be understood as operations such as the output and input of the processor, and can also be understood as the sending and receiving operations performed by the radio frequency circuit and the antenna. The present application does not make any limitations in this regard.

[0099] In a twelfth aspect, a communication system is provided, including at least one of the foregoing first host node, first network element, or second host node.

[0100] In a thirteenth aspect, a computer-readable storage medium is provided. The computer-readable medium stores program code executed by a user equipment, and the program code includes methods for executing any one of the possible implementation manners of the foregoing first aspect to fourth aspect.

[0101] In a fourteenth aspect, a computer program product including instructions is provided. When the computer program product runs on a computer, the computer is caused to execute the methods in any one of the possible implementation manners of the foregoing first aspect to fourth aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0102] Figure 1 is a communication network architecture diagram of integrated access and backhaul provided by the present application.

[0103] Figure 2 is a system architecture diagram applicable to embodiments of the present application.

[0104] Figure 3 is a schematic diagram of relay node migration exemplified by embodiments of the present application.

[0105] Figure 4 is a schematic flowchart of a communication method 400 provided by the present application.

[0106] Figure 5 is a schematic flowchart of a communication method 500 provided by the present application.

[0107] Figure 6 is a schematic structural diagram of a communication device 600 provided by embodiments of the present application.

[0108] Figure 7 is a schematic structural diagram of a communication device 700 provided by embodiments of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0109] Next, the technical solutions in the present application will be described with reference to the drawings.

[0110] The technical solution of the embodiment of the present application can be applied to various communication systems, such as: Global System for Mobile Communications (GSM) system, Code Division Multiple Access (CDMA) system, Wideband Code Division Multiple Access (WCDMA) system, General Packet Radio Service (GPRS), Long Term Evolution (LTE) system, LTE Frequency Division Duplex (FDD) system, LTE Time Division Duplex (TDD), Universal Mobile Telecommunication System (UMTS), Worldwide Interoperability for Microwave Access (WiMAX) communication system, 5th Generation (5G) system or future evolved communication systems, Vehicle-to-Everything (V2X), where V2X can include Vehicle-to-Network (V2N), Vehicle-to-Vehicle (V2V), Vehicle-to-Infrastructure (V2I), Vehicle-to-Pedestrian (V2P), etc., Long Term Evolution-Vehicle (LTE-V), Internet of Vehicles, Machine Type Communication (MTC), Internet of Things (IoT), Long Term Evolution-Machine (LTE-M), Machine-to-Machine (M2M), Device-to-Device (D2D), etc.

[0111] It can be understood that the embodiments of the present application can be applied to independently deployed 5G or LTE systems, and can also be applied to non-independently deployed 5G or LTE systems, such as scenarios of dual connectivity (DC), multi-connectivity (MC), etc. The present application does not limit this.

[0112] Figure 1 It is a communication network architecture diagram of integrated access and backhaul provided by the present application.

[0113] As Figure 1 shown, the IAB network includes an access link and a backhaul link, and the terminal device is connected to the IAB host through the IAB node. In the IAB network, on a transmission path between the terminal device and the IAB host, one or more IAB nodes may be included. Each IAB node needs to maintain a wireless backhaul link facing the parent node, and also needs to maintain a wireless link with the child node. If the child node of the IAB node is a terminal, the link between the IAB node and the child node (i.e., the terminal device) is a wireless access link. If the child node of the IAB node is another IAB node, the link between the IAB node and the child node (i.e., the other IAB node) is a wireless backhaul link.

[0114] The IAB host can be an access network element with complete base station functions, or an access network element in the form of a separated centralized unit (CU) and distributed unit (DU). The IAB host is connected to a core network element (such as a 5G core network) that serves the terminal device, and provides a wireless backhaul function for the IAB node.

[0115] The IAB node can be composed of a mobile termination (MT) part and a distributed unit (DU) part. Among them, when the IAB node faces its parent node, it can act as a terminal device, that is, in the role of the MT; when the IAB faces its child node (the child node may be another IAB node or an ordinary terminal device), it is regarded as a network device, that is, in the role of the DU.

[0116] For the convenience of description hereinafter, the centralized unit of the IAB host is simply referred to as the host CU, and the distributed unit of the IAB host is simply referred to as the host DU. Among them, the host CU can be in the form of separation of the control plane (CP) and the user plane (UP). For example, the host CU can be composed of a CU-CP and one (or more) CU-UPs.

[0117] The IAB introduces a new protocol layer, the backhaul adaptation protocol (BAP) layer, in the wireless backhaul link. This protocol layer is located above the radio link control (RLC) layer and can be used to implement functions such as routing of data packets in the wireless backhaul link and bearer mapping.

[0118] Between the IAB node (the DU part of the IAB) and the host node (or host CU), an F1 interface (or called the F1* interface. In this article, it can be uniformly called the F1 interface, but the name is not limited) needs to be established. This interface supports the user plane protocol (F1-U / F1*-U) and the control plane protocol (F1-C / F1*-C).

[0119] Figure 2 It is the system architecture diagram applicable to the embodiments of this application.

[0120] As Figure 2 shown, the DU part of the IAB node (i.e., Figure 2 the IAB-node-DU shown below, hereinafter collectively referred to as IAB-DU) is logically connected to the IAB-donor-CU (i.e., Figure 2 the IAB-host-CU shown) through the F1 interface. That is to say, Figure 2 the F1 connection in

[0121] The terminal device in the embodiments of the present application may refer to a user equipment (UE), an access terminal, a user unit, a user station, a mobile station, a mobile phone, a remote station, a remote terminal, a mobile device, a user terminal, a wireless communication device, a user agent, or a user device. The terminal in the embodiments of the present application may be a mobile phone, a tablet computer (pad), a computer with wireless transceiver function, a virtual reality (VR) terminal, an augmented reality (AR) terminal, a wireless terminal in industrial control, a wireless terminal in self-driving, a wireless terminal in remote medical, a wireless terminal in smart grid, a wireless terminal in transportation safety, a wireless terminal in smart city, a wireless terminal in smart home, a cellular phone, a cordless phone, a session initiation protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA), a handheld device with wireless communication function, a computing device, or other processing devices connected to a wireless modem, a vehicle-mounted device, a wearable device, a terminal in a 5G network, or a terminal in a future evolved network, etc.

[0122] Among them, the wearable device can also be called a wearable intelligent device, which is the general term for devices developed by applying wearable technology to intelligent design of daily wear, such as glasses, gloves, watches, clothing, and shoes. The wearable device is a portable device that is directly worn on the body or integrated into the user's clothes or accessories. The wearable device is not only a hardware device, but also realizes powerful functions through software support, data interaction, and cloud interaction. Broadly speaking, wearable intelligent devices include those with complete functions and large sizes that can realize complete or partial functions without relying on a smart phone, such as smart watches or smart glasses, etc., and those that only focus on a certain type of application function and need to cooperate with other devices such as smart phones, such as various smart bracelets and smart jewelry for physical sign monitoring.

[0123] The host nodes in the embodiments of the present application include, but are not limited to, IAB host nodes. The IAB host nodes include, but are not limited to, evolved node B (eNB), radio network controller (RNC), node B (NB), radio network controller (RNC), base station controller (BSC), base transceiver station (BTS), home base station (e.g., home evolved node B, or home node B, HNB), base band unit (BBU), access point (AP) in a wireless fidelity (WIFI) system, wireless relay node, wireless backhaul node, transmission point (TP), or transmission and reception point (TRP), etc. It can also be a gNB in a 5G system, such as NR, or a transmission point (TRP or TP), one or a group of antenna panels (including multiple antenna panels) of a base station in a 5G system, or it can also be a network node constituting a gNB or a transmission point, such as a base band unit (BBU), or a distributed unit (DU), etc. In some deployments, the IAB host node can include a CU and a DU, or the IAB host node is a radio access network (RAN) device including a CU node and a DU node.

[0124] It should be understood that the IAB host, IAB node, and terminal device in the embodiments of the present application can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; or deployed on water; or deployed on airplanes, balloons, and satellites in the air. The embodiments of the present application do not limit the application scenarios of the IAB host, IAB node, and terminal device.

[0125] The IAB node in the embodiments of the present application, that is, the relay device (node), can be a type of terminal device. For specific examples, refer to the above enumeration of terminal devices and will not be elaborated here.

[0126] It should be noted that Figure 1 and Figure 2 are only examples and do not constitute a limitation to the present application. Those of ordinary skill in the art know that with the evolution of the network architecture and the emergence of new service scenarios, the technical solutions provided by the present application are equally applicable to similar technical problems.

[0127] When an IAB node is deployed on a movable carrier such as a vehicle, the IAB node can be referred to as a mobile IAB node (i.e., a movable IAB node) or a mobile relay node (RN). Collectively referred to as a mobile relay node hereinafter, the partial migration process of the relay node and the complete migration process of the mobile relay node are introduced below.

[0128] Figure 3 It is a schematic diagram of the relay node migration exemplified in the embodiments of the present application.

[0129] Figure 3 (a) of is a schematic diagram of the partial migration of the relay node exemplified in the embodiments of the present application. As Figure 3 shown in (a) of, the IAB node where migration occurs is called a boundary node, such as the mobile IAB node in the figure, denoted as the mIAB node. Before partial migration, there is an RRC connection between mIAB-MT and CU1; there is an F1 interface between mIAB-DU and CU1, and communication is carried out through the source path During partial migration, the mIAB-MT undergoes a cell handover across CUs and establishes an RRC connection with the host-CU2. At this time, in order to avoid introducing the re-establishment process of the F1 interface, the mIAB-DU can still maintain the F1 interface with CU1 and does not establish an F1 interface with the host-CU2. Therefore, the communication path between the mIAB-DU and the host-CU1 becomes a cross-topology path: Among them, the host-CU1 and the host-CU2 can be respectively referred to as the F1-terminating CU and the non-F1-terminating CU (or RRC-terminating CU), and can also be referred to as the source CU and the target CU. It should be noted that when data is transmitted on the cross-topology path, it does not pass through the host-CU2, and the host-CU1 and the Donor-DU2 communicate directly through the IP network.

[0130] In the scenario of partial migration of relay nodes, the F1 terminating CU sends an IAB transport migration management request message to the non F1-terminating CU to request the establishment of cross-topology flow transmission. If the non F1-terminating CU agrees to establish it, it will reply to the F1 terminating CU with an IAB transport migration management response message; if the non F1-terminating CU does not agree to establish it, it will reply to the F1 terminating CU with an IAB transport migration management reject message. If the subsequent F1 terminating CU or non F1-terminating CU wants to perform operations such as modifying or withdrawing the quality of service (QoS) of the flow, they can also exchange IAB transport migration modification request / response messages.

[0131] Figure 3 (b) shows a schematic diagram of consecutive partial migration of relay nodes. As Figure 3 shown in (b), when mIAB-MT switches from CU2 to CU3, the F1 interface of the DU is always associated with CU1. Figure 3 In (b), the mIAB node is directly connected to the host-DU, but there is no limitation. There may be other IAB nodes between the mIAB node and the host-DU. In addition, there is no limitation on how the mIAB-MT reaches the host-CU2. For example, the mIAB-MT may switch from the host-CU1 to the host-CU2 (as Figure 3 shown in (a)), but it may also switch from other CUs to under the host-CU2.

[0132] Figure 3 (c) shows a schematic diagram of DU migration. Considering the mobility of IAB nodes or the requirements of RAN-side load balancing, the IAB node can trigger the DU migration process by the source F1-terminated host CU or OAM, that is, migrate the F1 connection of the mIAB-DU from the source F1-terminated host CU to the target F1-terminated host CU. As Figure 3As shown in (c), the mIAB node includes two logical DUs, that is, mIAB-DU includes mIAB-DUa and mIAB-DUb. Initially, mIAB-DU establishes an F1 connection with the host-CU1 through mIAB-DUa. The host-CU1 is the source F1-terminating Donor-CU. At this time, mIAB-DUb is in a pending activation state. mIAB-MT is connected to the host-CU2 through RRC. The host-CU2 is the non-F1-terminating host CU. After movement, mIAB-DUb can be triggered by the host-CU1 or OAM to establish a new F1 connection with the host-CU3. The host-CU3 is the target F1-terminating Donor-CU.

[0133] It can be understood that mIAB-DUa and mIAB-DUb can be regarded as two different DUs, each with its own F1 interface. After the DU migration in the mIAB node is completed, the terminal device needs to perform a handover from the cell managed by mIAB-DUa to the cell managed by mIAB-DUb.

[0134] Hereinafter, the host-CU will be abbreviated as the host CU. For example, the host-CU1 will be abbreviated as the host CU1, the host-CU2 will be abbreviated as the host CU2, and so on.

[0135] It should be noted that Figure 2 and Figure 3 the host CUs in are only examples. In actual deployment, the host CU1 and the host CU2 can be the same CU, or the host CU2 and the host CU3 can be the same CU. This application does not make any restrictions on this.

[0136] Next, the related content of the tracking area (TA) related to the embodiments of this application will be introduced.

[0137] TA is a concept introduced by the LTE / NR system for the location management of UEs. TA is a cell-level configuration. Multiple cells can be configured with the same TA, and a cell can only belong to one TA. When a UE registers and accesses the network, the core network will assign a UE registration area (RA) to each UE. The RA can contain a tracking area identity List (TAI List). Among them, the TAI can be composed of a public land mobile network (PLMN) and a tracking area code (TAC). The TAI information is located in the SIB1 message broadcast by the cell under the DU.

[0138] The paging range of the core network for the UE (denoted as CN Paging) can be determined according to the TAI. Exemplarily, when there is traffic arriving for UE#1 on the core network side, if UE#1 is in the idle state, then the core network (e.g., the AMF connected to the RAN within the TAIList, e.g., connected via the NG interface) can send a paging message to the RAN within the current RA of UE#1, and this paging message carries the identifier of UE#1; the RAN broadcasts the paging message carrying the identifier of UE#1; after UE#1 receives the paging message, it returns from the idle state to the connected state for traffic transmission. That is, when the core network wants to initiate paging for UE#1, it needs to know the TAI List corresponding to the current location of UE#1. When an idle UE moves to a cell that does not belong to this TAIList, the UE will initiate a tracking area update (TAU) process to actively access the network and return to the connected state; the core network determines the current location of the UE and updates the RA of the UE, that is, reallocates the TAI List corresponding to the TA to which the cell where the UE is currently located belongs. In addition to the case where the UE moves out of the TAI List, the UE can also periodically execute the TAU process to enable the core network to know the location of the UE.

[0139] Similarly, the RAN can also allocate a list of RAN area codes (RANAC List) to the UE for the RAN side to manage the location of the inactive state UE. For example, when there is traffic for UE#2 (UE#2 is in the inactive state) arriving at the core network side, the core network can consider that UE#2 is still in the connected state under the last serving gNB, and send the traffic data of UE#2 to the last serving gNB; the last serving gNB knows that UE#2 is in the inactive state. After receiving the traffic data of UE#2 from the core network, the last serving gNB sends a paging message (RAN Paging) to the gNBs within the RANAC List that have an Xn interface with UE#2. The paging message carries the identifier of UE#2 to enable all gNBs within the RANAC List that have an Xn interface with UE#2 to search for UE#2; after receiving the paging message carrying the identifier of UE#2 broadcast by the gNBs that have an Xn interface with UE#2, UE#2 returns from the inactive state to the connected state for traffic transmission. Similar to TAU, when an inactive state UE moves out of the cell of the RANAC List, a RAN-based notification area update (RNAU) process can be executed to return to the connected state. At this time, the last serving gNB of the UE is the currently serving gNB, and the currently serving gNB will re-allocate the RANAC List for the UE, and the UE can also perform RNAU periodically so that the core network can learn the location of the UE.

[0140] In the IAB communication network, the TAC / RANAC broadcast by the DU of the mobile relay node (denoted as mIAB-DU) is related to the current geographical location of the mIAB node and may therefore change. To save signaling overhead, it can be considered to keep the TAC / RANAC broadcast by the mIAB-DU unchanged.

[0141] Taking TAC as an example, if the TAC broadcast by mAB-DU does not change, the AMF of the idle UE residing in the cell under mAB-DU may not be able to page the UE. From the above introduction to CN Paging, it can be seen that when the AMF is connected to the RAN in the TAIList, the AMF will send a paging message to the RAN in the TAI List. If the mAB node moves to a farther place and the TAC is not changed at this time, the AMF may not be connected to the host CU corresponding to the cell where the UE resides, which will cause the AMF to be unable to page the UE, causing the UE to lose connection with the network.

[0142] For example, in Figure 3 In the DU migration scenario shown in (c), the source CU (CU1) and target CU (CU3) of mAB-DU may be far apart. Assume that UE#1 enters the idle state under CU1. After DU migration occurs, UE#1 reselects the cell under mAB-DU2, and its corresponding host CU is host-CU3. If the AMF connected to the UE before entering the idle state (the UE's registered AMF, denoted as AMF#1) is near the area of ​​host-CU1, it may not be connected to host-CU3, which may cause AMF#1 to be unable to page UE#1 after the data of UE#1 arrives.

[0143] Similarly, if the RANAC broadcast by the mIAB-DU remains unchanged, the last serving gNB of an inactive UE residing in the cell under the mIAB-DU may be unable to page the UE.

[0144] For example, in Figure 3 In (c), host-CU1 is the last serving gNB. When the UE resides in mIAB-DU2, there may be no Xn interface between host-CU1 and host-CU3, which makes host-CU1 unable to page the UE under host-CU3 through RAN Paging. Therefore, when the TAC / RANAC broadcast by mIAB-DU does not change, how to discover and page the UE under the TAI List and / or RANAC List is a problem that needs to be considered.

[0145] In view of this, the present application provides a communication method and a communication device, which are beneficial to improving and solving the above-mentioned problems.

[0146] Figure 4 It is a flowchart of a communication method 400 provided in this application. Figure 4 The exemplary method 400 may be applied toFigure 3 Example DU migration scenario. The method includes the following steps.

[0147] S410, the first host node releases the first terminal device to the non-connected state.

[0148] Among them, the first terminal device is a terminal device in the cell managed by the mobile relay node. For example, the mobile relay node can refer to the description of the mobile IAB node (i.e., the IAB node that can move) in the above text.

[0149] The first host node can be understood as the source host node of the mobile relay node, and there is a connection between the mobile relay node and the first host node. For example, there is an RRC connection between the MT of the mobile relay node and the CU of the first host node; and / or there is an F1 interface between the DU of the mobile relay node and the CU of the first host node.

[0150] For example, the first host node can release at least one terminal device managed in the mobile relay node to the non-connected state according to the current network congestion level, the arrival of service data of the terminal device, etc. The first terminal device is one of the at least one terminal device; the non-connected state can include the idle state or the inactive state.

[0151] Optionally, the method further includes:

[0152] S420, the first host node saves the identification information of the access and mobility management network element corresponding to the first terminal device.

[0153] Exemplarily, after the first host node releases the first terminal device to the non-connected state, the first host node saves the identification information of the access and mobility management network element corresponding to the first terminal device.

[0154] Among them, the access and mobility and management network element corresponding to the first terminal device can also be understood as the access and mobility management network element registered by the first terminal device, or the access and mobility management network element currently providing services for the first terminal device.

[0155] For example, the identification information of the access and mobility management network element can be the ID of the access and mobility management network element or the IP address of the access and mobility management network element.

[0156] Optionally, the first host node can also save the identification of the first terminal device; or rather, the first host node saves the correspondence between the identification of the first terminal device and the identification of the access and mobility management network element.

[0157] Exemplarily, the identification of the first terminal device includes but is not limited to the following identifications:

[0158] The paging radio network temporary identifier (P-RNTI), cell radio network temporary identifier (C-RNTI), subscription permanent identifier (SUPI), subscription concealed identifier (SUCI), generic public subscription identifier (GPSI), permanent equipment identifier (PEI), or mobile subscriber international ISDN / PSTN number (MSISDN) of the UE, where ISDN is the integrated service digital network and PSTN is the public switched telephone network, etc.

[0159] S430, the first host node sends first information to the first network element. Correspondingly, the first network element receives the first information from the first host node.

[0160] Wherein, the first information indicates determining whether it is reachable between the first network element and the second host node. The second host node is the host node to which the mobile relay node is to be connected, or in other words, the second host node is the target host node of the mobile relay node.

[0161] Exemplarily, in the case of determining that the mobile relay node performs DU migration (which can be triggered by the first host node or OAM), the first host node determines the target host node (i.e., the second host node) for the mobile relay node to perform DU migration, and the first host node sends the first information to the first network element.

[0162] Exemplarily, whether the first network element and the second host node are reachable can be understood as whether there is or can establish an NG interface between the first network element and the second host node; or whether the first host node and the second host node are IP reachable (i.e., whether the IP address is reachable).

[0163] Wherein, the first network element can be the access and mobility management network element corresponding to the first terminal device, or the access network device that the first terminal device was connected to most recently before entering the disconnected state.

[0164] Exemplarily, when the first network element is the access and mobility management network element corresponding to the first terminal device, the first host node may send the first information to the first network element through a (protocol for NG interface, NGAP) message.

[0165] The first information may include the identification information of the second host node. For example, the identification information may be the gNBID of the second host node or the IP address of the second host node.

[0166] Optionally, the first information may also carry the identification of the first terminal device.

[0167] S440, the first network element determines whether the first network element and the second host node are reachable according to the first information.

[0168] Specifically, the first network element may determine the second host node according to the first information, and then determine whether the first network element and the second host node are reachable.

[0169] Exemplarily, the first network element determines whether the first network element and the second host node are reachable by determining whether there is an NG interface between the first network element and the second host node, or whether an NG interface can be established.

[0170] Alternatively, when the first information carries the IP address of the second host node, the first network element may determine whether it is reachable from the second host node by determining whether the IP address of the second host node is reachable.

[0171] It should be understood that if the first network element is an access and mobility management network element and there is no NG interface or an NG interface connection cannot be established between the first network element and the second host node, then the first network element and the second host node are not reachable; otherwise, the first network element and the second host node are reachable.

[0172] Alternatively, if the first network element is an access network device and there is no Xn interface or an Xn interface connection cannot be established between the first network element and the second host node, then the first network element and the second host node are not reachable; otherwise, the first network element and the second host node are reachable.

[0173] Alternatively, the first network element and the second host node are IP reachable, that is, the first network element and the second host node are reachable, otherwise they are not reachable.

[0174] It should be understood that the above NG interface and Xn interface are only examples of the communication interfaces between the first host node and the access and mobility management network element, and between the first host node and the access network device. This application is not limited thereto. For example, in different communication systems, this communication interface may also be other interfaces or this communication interface may also have other names.

[0175] Optionally, when it is determined that the first network element is unreachable from the second host node, if the first network element is the access and mobility management network element corresponding to the first terminal device, the subsequent steps can be divided into two cases:

[0176] Case 1:

[0177] The first network element sends a paging message to the first host node. Correspondingly, the first host node receives the paging message from the first network element.

[0178] Wherein, the paging message is used to page the first terminal device. The paging message may refer to the CNPaging message in the above text.

[0179] Further, the method further includes: the first host node sends the paging message to the first terminal device. Correspondingly, the first terminal device receives the paging message from the first host node.

[0180] Exemplarily, the first host node may broadcast a paging message carrying the identifier of the first terminal device; after the first terminal device receives the paging message, it returns from the idle state to the connected state.

[0181] Case 2:

[0182] The first network element re-determines the registration area (RA) of the first terminal device.

[0183] Exemplarily, the first network element re-determines the TAC List corresponding to the first terminal device. The TAC List may include the TAC where the second host node is located.

[0184] In this case, when the first terminal device subsequently establishes a connection with the second host node, the core network may page the first terminal device back to the connected state based on the updated RA of the first terminal device.

[0185] Optionally, when it is determined that the first network element is unreachable from the second host node, if the first network element is the access network device that the first terminal device was connected to most recently before entering the non-connected state (the access network device that the first terminal device was connected to most recently is the first host node), the subsequent steps may include:

[0186] Case 3:

[0187] The first host node sends the paging message to the first terminal device. Correspondingly, the first terminal device receives the paging message from the first host node.

[0188] Exemplarily, the first host node sends the paging message to the gNB within the RANAC List that has an Xn interface with the first terminal device. The paging message may refer to the RAN Paging in the foregoing text. The paging message carries the identifier of the first terminal device, so that all gNBs within the RANAC List that have an Xn interface with the first terminal device search for the first terminal device; after receiving the paging message carrying the identifier of the first terminal device, the first terminal device returns from the inactive state to the connected state.

[0189] Case 4:

[0190] The first host node re-determines the RANAC List of the first terminal device.

[0191] Exemplarily, the RANAC List corresponding to the first terminal device re-determined by the first host node may include the RANAC corresponding to the second host node.

[0192] In this case, when the first terminal device subsequently establishes a connection with the second host node, the second host node may page the first terminal device back to the connected state based on the updated RANAC List of the first terminal device.

[0193] It should be understood that the processing of other terminal devices released by the first host node back to the non-connected state may also refer to the above steps. That is, the above steps may also be applied to other terminal devices released by the first host node back to the non-connected state, so that the network side or the access network side discovers the other terminal devices.

[0194] Optionally, the method further includes:

[0195] S450, the first host node sends second information to the second host node. Correspondingly, the second host node receives the second information from the first host node.

[0196] Wherein, the second information includes the identifier of the access and mobility management network element corresponding to each second terminal device among at least one second terminal device, and / or the identifier of the access network device of the most recent connection before each second terminal device enters the non-connected state.

[0197] Optionally, the second information may further include the identifier of each second terminal device; or, the second information may include the correspondence between the identifier of each second terminal device and the access and mobility management network element (i.e., the access and mobility management network element corresponding to each second terminal device).

[0198] Wherein, the second terminal device is a terminal device in the cell managed by the mobile relay node, the second terminal device is released by the third host node to the disconnected state, and the third host node includes the host node connected before the mobile relay node is connected to the first host node. The second information may come from the third host node.

[0199] For example, in the case where the third host node releases the second terminal device managed by the mobile relay node back to the disconnected state, the third host node may send the identifier of the access and mobility management network element corresponding to the second terminal device, and / or the identifier of the access network device of the most recent connection, to the first host node.

[0200] Based on the above solution, by sending the second information to the second node, in the case where the mobile relay node moves to the target host node, the second host node and the target host node can interact with the second information to discover the second terminal device in the idle state.

[0201] Optionally, the method further includes:

[0202] S460, the first host node sends third information to the second network element. Correspondingly, the second network element receives the third information from the first host node.

[0203] Wherein, the third information indicates determining whether the second network element and the second host node are reachable, and the second network element is the access and mobility management network element corresponding to the second terminal device, or the access network device of the most recent connection before the second terminal device enters the disconnected state.

[0204] The specific manner in which the first host node sends the third information to the second network element may refer to the manner in which the first host node sends the first information to the first network element in S430.

[0205] The third information includes the identifier information of the second host node. The identifier information of the second host node may refer to the description in S430.

[0206] Optionally, the method further includes:

[0207] The second network element determines whether the second network element and the second host node are reachable according to the third information. The specific determination manner of whether the second network element and the second host node are reachable may refer to the description in S440.

[0208] Optionally, when it is determined that the second network element is unreachable from the second host node, if the second network element is an access and mobility management network element, the method further includes:

[0209] The second network element sends a paging message to the first host node. Correspondingly, the first host node receives the paging message from the second network element, and the first host node sends a paging message to the second terminal device. The paging message is used to page the second terminal device. The paging method of the first host node for the second terminal device may refer to Case 1 in S440.

[0210] Optionally, the second network element may also update the RA of the second terminal device. Specifically, it may refer to Case 2 in S440.

[0211] Optionally, when it is determined that the second network element is unreachable from the second host node, if the second network element is the access network device of the most recent connection, the method further includes:

[0212] The access network device sends the paging message to the second terminal device. Correspondingly, the second terminal device receives the paging message from the first host node. The second terminal device returns to the connected state according to the paging message. Specifically, it may refer to Case 3 in S440. Optionally, the access network device re-determines the RAN AC List of the second terminal device. Specifically, it may refer to Case 4 in S440.

[0213] Figure 5 It is a schematic flowchart of a communication method 500 provided by this application. Figure 5 The exemplary method 500 may be applied to Figure 3 An exemplary DU migration scenario. The method includes the following steps.

[0214] S510, the first host node releases the first terminal device to the non-connected state.

[0215] The first terminal device is a terminal device in a cell managed by a mobile relay node; the first host node may be understood as the source host node of the mobile relay node, and there is a connection between the mobile relay node and the first host node; the first terminal device is one of the at least one terminal device; the non-connected state may include the idle state or the inactive state.

[0216] This step may specifically refer to the description in S410.

[0217] Optionally, the method further includes:

[0218] S520, the first host node saves the identification information of the access and mobility management network element corresponding to the first terminal device.

[0219] Exemplarily, after the first host node releases the first terminal device to the disconnected state, the first host node saves the identification information of the access and mobility management network element corresponding to the first terminal device.

[0220] Optionally, the first host node may also save the identifier of the first terminal device; alternatively, the first host node saves the correspondence between the identifier of the first terminal device and the identifier of the access and mobility management network element. The identifier of the first terminal device may refer to the description in S420.

[0221] S530, the first host node sends first information to the second host node. Correspondingly, the second host node receives the first information from the first host node.

[0222] Wherein, the first information indicates determining whether the second host node is reachable from the first network element.

[0223] The first network element may be the access and mobility management network element corresponding to the first terminal device or the access network device to which the first terminal device was last connected before entering the disconnected state. In the case where the first network element is the access and mobility management network element corresponding to the first terminal device, the first information may include the identifier of the access and mobility management network element.

[0224] Optionally, the first information may also carry the identifier of the first terminal device.

[0225] S540, the second host node determines whether it is reachable from the first network element according to the first information.

[0226] Specifically, the second host node may determine the first network element according to the first information, and then determine whether it is reachable from the first network element. The specific manner in which the second host node determines whether it is reachable from the first network element may refer to the determination manner in S440 for the first network element to determine whether it is reachable from the second host node.

[0227] Optionally, in the case where it is determined that it is not reachable from the first network element, the method further includes:

[0228] The second host node sends a request message (denoted as request message #1) to the first host node, and the request message #1 is used to request paging the first terminal device, and the request message #1 may carry the identifier of the first terminal device.

[0229] Accordingly, the first host node receives the request message #1 from the second host node. The first host node sends a request message #2 to the access and mobility management network element corresponding to the first terminal device according to the request message #1, and the request message #2 is used for the access and mobility management network element to page the first terminal device.

[0230] Furthermore, the access and mobility management network element pages the first terminal device. Specifically, the process of CNPaging in the above text can be referred to.

[0231] Alternatively, the first host node sends the paging message to the first terminal device. Specifically, the process of RANPaging in the above text can be referred to.

[0232] Optionally, the method further includes:

[0233] S550, the first host node sends second information to the second host node. Accordingly, the second host node receives the second information from the first host node.

[0234] Wherein, the second information includes the identifier of the access and mobility management network element corresponding to each second terminal device in at least one second terminal device, and / or the identifier of the access network device to which each second terminal device was last connected before entering the disconnected state.

[0235] Optionally, the second information may further include the identifier of each second terminal device; or, the second information may include the correspondence between the identifier of each second terminal device and the identifier of the access and mobility management network element (i.e., the access and mobility management network element corresponding to each second terminal device).

[0236] Wherein, the second terminal device is a terminal device in the cell managed by the mobile relay node, and the second terminal device is released to the disconnected state by a third host node, and the third host node includes the host node to which the mobile relay node was connected before connecting to the first host node. The second information may come from the third host node. This step can specifically refer to the description in S450.

[0237] By sending the second information to the second node, in the case where the mobile relay node moves to the target host node, the second host node can interact with the target host node with the second information to discover the second terminal device in the idle state.

[0238] Optionally, the method further includes:

[0239] S560, the first host node sends third information to the second host node. Accordingly, the second host node receives the third information from the first host node.

[0240] Wherein, the third piece of information indicates whether it is determined that the second host node and the second network element are reachable. The second network element is the access and mobility management network element corresponding to the second terminal device, or the access network device to which the second terminal device was last connected before entering the disconnected state.

[0241] In the case where the second network element is the access and mobility management network element corresponding to the second terminal device, the third piece of information includes the identification information of the access and mobility management network element corresponding to the second terminal device.

[0242] Optionally, the method further includes:

[0243] The second host node determines whether it is reachable from the second network element according to the third piece of information. The specific determination method can refer to the description in S440.

[0244] Optionally, in the case where it is determined that it is not reachable from the second network element, the method further includes:

[0245] The second host node sends a request message to the first host node. The request message is used to request paging of the first terminal device, and the request message may carry the identification of the first terminal device.

[0246] Correspondingly, the first host node receives the request message from the second host node and pages the first terminal device according to the request message. Specifically, it can refer to the process of CN Paging in the foregoing text, or it can refer to the process of RAN Paging in the foregoing text.

[0247] Based on the above solution, by sending, by the first host node, indication information indicating whether it is determined that the first network element and the second host node are reachable to the first network element or the second host node, it can be enabled that when the first network element or the second host node determines that the first network element and the second host node are not reachable, the terminal device in the disconnected state managed by the mobile relay node is paged in a timely manner.

[0248] In this application, the "indication" can indicate explicitly and / or implicitly. Exemplarily, the implicit indication can be based on the location and / or resources for transmission; the explicit indication can be based on one or more parameters, and / or one or more indexes, and / or one or more bit patterns represented by it.

[0249] It can be understood that the sequence of steps in the embodiments of this application is determined according to the inherent logic of the solution implementation, and the serial numbers of the steps in the figure are only examples. Some optional features in the embodiments of this application can, in some scenarios, be independent of other features, and can also be combined with other features in some scenarios, without limitation.

[0250] The solutions in the embodiments of the present application can be reasonably combined and used. Moreover, the explanations or descriptions of various terms, similar operations, or steps appearing in the embodiments can be referred to or explained with each other in the respective embodiments, and no limitation is made thereto.

[0251] It can also be understood that in the above method embodiments, the methods and operations implemented by the first host node, the first network element, or the second host node can also be implemented by the components (such as chips, chip systems, processors, or circuits) of the first host node, the first network element, or the second host node.

[0252] It should be understood that the term "and / or" in the present application is merely a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. Here, A and B can be singular or plural. In addition, the character " / " in this article generally represents an "or" relationship between the preceding and following associated objects, but it may also represent an "and / or" relationship, and specific understanding can be made with reference to the context before and after.

[0253] In the present application, "at least one (item)" means one (item) or more than one (item), "at least two (items)" and "more than one (item)" mean two (items) or more than two (items). "At least one (item) of the following" or its similar expression means any combination of these items, including any combination of a single item or plural items. For example, at least one (item) of a, b, or c can represent: a, b, c, a - b, a - c, b - c, or a - b - c, where a, b, and c can be single or multiple. If not otherwise specified, multiple in the present application means 2 or more than 2.

[0254] As described above in combination with Figure 4 and Figure 5 the method embodiments of the embodiments of the present application are described. Next, the device embodiments of the embodiments of the present application are described. It can be understood that the descriptions of the method embodiments and the descriptions of the device embodiments can correspond to each other. Therefore, the parts not described can be referred to the previous method embodiments.

[0255] The above mainly introduced the solution provided by the embodiments of the present application from the perspective of the interaction between each network element. It can be understood that each network element, such as a transmitting device or a receiving device, includes corresponding hardware structures and / or software modules for implementing the above functions. Those skilled in the art should be able to realize that, in combination with the units and algorithm steps of each example described in the embodiments disclosed in this article, the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a certain function is executed in the way of hardware or computer software driving hardware depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present application.

[0256] The embodiments of the present application can divide the functional modules of the transmitting device or the receiving device according to the above method examples. For example, each functional module can be divided corresponding to each function, or two or more functions can be integrated into one processing module. The above integrated module can be implemented in the form of hardware or in the form of a software functional module. It should be noted that the division of modules in the embodiments of the present application is illustrative, only a logical function division, and there can be other division methods in actual implementation. The following takes the example of dividing each functional module corresponding to each function for illustration.

[0257] Figure 6 It is a schematic structural diagram of a communication device 600 provided by the embodiments of the present application.

[0258] The device 600 includes a transceiver unit 610. The transceiver unit 610 can be used to implement corresponding communication functions. The transceiver unit 610 can also be referred to as a communication interface or a communication unit.

[0259] Optionally, the transceiver unit 610 can include a sending unit and a receiving unit. The sending unit is used to perform the sending operation in the above method embodiments. The receiving unit is used to perform the receiving operation in the above method embodiments.

[0260] It should be noted that the communication device 600 can include a sending unit but not a receiving unit. Or, the communication device 600 can include a receiving unit but not a sending unit. Specifically, it depends on whether the above scheme executed by the communication device 600 includes a sending action and a receiving action.

[0261] Optionally, the device 600 further includes a processing unit 620. The processing unit 620 can be used to enable the device to implement the processing actions performed by the first host node, the first network element, or the second host node in the foregoing method embodiments.

[0262] Optionally, the device 600 further includes a storage unit, which can be used to store instructions and / or data. The processing unit 620 can read the instructions and / or data in the storage unit so that the device implements the actions performed by the first host node, the first network element, or the second host node in the foregoing various method embodiments.

[0263] In one design, the device 600 can be the first host node in the foregoing embodiment, or a component of the first host node (such as a chip, a chip system, a processor, or a circuit). The device 600 can implement the steps or processes corresponding to those performed by the first host node in the foregoing method embodiments. Among them, the transceiver unit 610 can be used to perform the operations related to the transceiver of the first host node in the foregoing method embodiments, and the processing unit 620 can be used to perform the operations related to the processing of the first host node in the foregoing method embodiments.

[0264] The device 600 can implement the steps or processes corresponding to those performed by the first host node in the method embodiments according to the embodiments of the present application. The device 600 can include units for performing Figure 4 or Figure 5 the method performed by the first host node in the illustrated embodiments.

[0265] In another design, the device 600 can be the first network element in the foregoing embodiment, or a component of the first network element (such as a chip, a chip system, a processor, or a circuit). The device 600 can implement the steps or processes corresponding to those performed by the first network element in the foregoing method embodiments. Among them, the transceiver unit 610 can be used to perform the operations related to the transceiver of the first network element in the foregoing method embodiments, and the processing unit 620 can be used to perform the operations related to the processing of the first network element in the foregoing method embodiments.

[0266] The device 600 can implement the steps or processes corresponding to those performed by the first network element in the method embodiments according to the embodiments of the present application. The device 600 can include units for performing Figure 4 or Figure 5 the method performed by the first network element in the illustrated embodiments.

[0267] In another design, the device 600 can be the second host node in the foregoing embodiment, or a component of the second host node (such as a chip, a chip system, a processor, or a circuit). The device 600 can implement the steps or processes corresponding to those performed by the second host node in the foregoing method embodiments. Among them, the transceiver unit 610 can be used to perform the operations related to the transceiver of the second host node in the foregoing method embodiments, and the processing unit 620 can be used to perform the operations related to the processing of the second host node in the foregoing method embodiments.

[0268] The apparatus 600 can implement the steps or processes performed by the second host node in the method embodiments corresponding to the embodiments of the present application. The apparatus 600 may include units for performing Figure 4 or Figure 5 the method performed by the second host node in the illustrated embodiments.

[0269] Figure 7 is a schematic structural diagram of a communication apparatus 700 provided by an embodiment of the present application. The apparatus 700 includes a processor 710. The processor 710 is coupled to a memory 720. The memory 720 is used to store computer programs or instructions and / or data. The processor 710 is used to execute the computer programs or instructions stored in the memory 720, or read the data stored in the memory 720, so as to execute the methods in the above method embodiments.

[0270] In some embodiments, the processor 710 is one or more.

[0271] In some embodiments, the memory 720 is one or more.

[0272] In some embodiments, the memory 720 is integrated with the processor 710 or is separately provided.

[0273] In some embodiments, as Figure 7 shown, the apparatus 700 further includes a transceiver 730. The transceiver 730 is used for receiving and / or transmitting signals. For example, the processor 710 is used to control the transceiver 730 to receive and / or transmit signals.

[0274] As a solution, the apparatus 700 is used to implement the operations performed by the first host node in the above method embodiments.

[0275] As another solution, the apparatus 700 is used to implement the operations performed by the first network element in the above method embodiments.

[0276] As another solution, the apparatus 700 is used to implement the operations performed by the first host node in the above method embodiments.

[0277] It should be understood that the processor mentioned in the embodiments of the present application may be a central processing unit (CPU), or may also be other general-purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc.

[0278] It should also be understood that the memory mentioned in the embodiments of the present application may be volatile memory and / or non-volatile memory. Among them, the non-volatile memory may be a read-only memory (ROM), programmable ROM (PROM), erasable PROM (EPROM), electrically erasable PROM (EEPROM), or flash memory. The volatile memory may be a random access memory (RAM). For example, the RAM may be used as an external cache. By way of example and not limitation, the RAM includes the following various forms: static random access memory (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchlink DRAM (SLDRAM), and direct rambus RAM (DR RAM).

[0279] It should be noted that when the processor is a general-purpose processor, DSP, ASIC, FPGA, or other programmable logic device, discrete gate or transistor logic device, discrete hardware component, the memory (storage module) may be integrated in the processor.

[0280] It should also be noted that the memory described herein is intended to include, but not be limited to, these and any other suitable types of memory.

[0281] An embodiment of the present application further provides a computer-readable storage medium, on which computer instructions for implementing the methods executed by the first host node, the first network element, or the second host node in the above method embodiments are stored.

[0282] An embodiment of the present application further provides a computer program product, including instructions, which when executed by a computer, implement the methods executed by the first host node, the first network element, or the second host node in the above method embodiments.

[0283] An embodiment of the present application further provides a communication system, which includes at least one of a first host node, a first network element, and a second host node. Optionally, the communication system may further include a second network element and / or a third host node.

[0284] For the explanations and beneficial effects of the relevant content in any of the above provided devices, reference may be made to the corresponding method embodiments provided above, and details are not described herein again.

[0285] In several embodiments provided by the present application, it should be understood that the disclosed devices and methods may be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the units is only a logical function division, and there may be other division methods in actual implementation. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. In addition, the displayed or discussed couplings or direct couplings or communication connections to each other may be through some interfaces, and the indirect couplings or communication connections of the devices or units may be in electrical, mechanical or other forms.

[0286] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the processes or functions described in the embodiments of the present application are generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. For example, the computer can be a personal computer, a server, or a network device, etc. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center by wire (such as coaxial cable, optical fiber, digital subscriber line (DSL)) or wirelessly (such as infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server or a data center that includes one or more integrated available media. The available medium can be a magnetic medium (such as a floppy disk, a hard disk, a magnetic tape), an optical medium (such as a DVD), or a semiconductor medium (such as a solid state disk (SSD), etc.). For example, the aforementioned available media include, but are not limited to: USB flash drives, external hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical discs, etc., all of which can store program codes.

[0287] As described above, the above are only specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present application can easily think of changes or substitutions, which should all be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A communication method, characterized in that, Applied to the first host node, the method includes: Releasing the first terminal device to the disconnected state, where the first terminal device is a terminal device managed by a mobile relay node, and there is a connection between the mobile relay node and the first host node; Sending first information to a first network element, where the first information indicates determining whether the first network element is reachable from a second host node, and the second host node is the host node to which the mobile relay node is to be connected.

2. The method according to claim 1, wherein The first network element includes any one of the following: The access and mobility management network element corresponding to the first terminal device, the access network device to which the first terminal device was last connected before entering the disconnected state.

3. The method according to claim 1 or 2, characterized in that, After releasing the first terminal device to the disconnected state, the method further includes: Saving the identifier of the access and mobility management network element corresponding to the first terminal device.

4. The method according to any one of claims 1 to 3, characterized in that, The first information includes the identifier information of the second host node.

5. The method according to claim 4, wherein If the first network element is not reachable from the second host node, the method further includes: Receiving a paging message from the first network element, where the paging message is used to page the first terminal device; Sending the paging message to the first terminal device.

6. The method according to any one of claims 1 to 5, characterized in that, The method further includes: Sending second information to the second host node, where the second information includes the identifier of the access and mobility management network element corresponding to each of at least one second terminal device, and / or the identifier of the access network device to which each of the second terminal devices was last connected before entering the disconnected state; where the second terminal device is a terminal device in the cell managed by the mobile relay node, and the second terminal device is released to the disconnected state by a third host node, and the third host node includes the host node to which the mobile relay node was connected before connecting to the first host node.

7. The method according to claim 6, wherein The method further includes: Sending third information to a second network element, where the third information indicates determining whether the second network element is reachable from the second host node, and the second network element is the access and mobility management network element corresponding to the second terminal device, or the access network device to which the second terminal device was last connected before entering the disconnected state.

8. The method according to claim 7, wherein The third information includes the identifier information of the second host node.

9. The method according to claim 7 or 8, characterized in that, If the second network element is not reachable from the second host node, the method further includes: Receiving a paging message from the second network element, where the paging message is used to page the second terminal device; Sending the paging message to the second terminal device.

10. The method according to any one of claims 6 to 9, characterized in that The method further includes: Saving the identifier of the access and mobility management network element corresponding to the second terminal device, and / or the identifier of the access network device to which the second terminal device was last connected before entering the disconnected state.

11. A communication method, characterized in that, Applied to the first host node, the method includes: Releasing the first terminal device to the disconnected state, where the first terminal device is a terminal device managed by a mobile relay node, and there is a connection between the mobile relay node and the first host node; Sending first information to the second host node, where the first information indicates determining whether the second host node is reachable from a first network element, and the second host node is the host node to which the mobile relay node is to be connected.

12. The method according to claim 11, wherein The first network element includes any one of the following: The access and mobility management network element corresponding to the first terminal device, and the access network device to which the first terminal device was last connected before entering the disconnected state.

13. The method according to claim 11 or 12, characterized in that, If the first network element is the access and mobility management network element corresponding to the first terminal device, after releasing the first terminal device to the disconnected state, the method further includes: Saving the identifier of the access and mobility management network element corresponding to the first terminal device.

14. The method according to claim 13, wherein The first information includes the identifier information of the access and mobility management network element corresponding to the first terminal device.

15. The method according to any one of claims 11 to 14, characterized in that If the second host node is unreachable from the first network element, the method further includes: Receiving a first request message from the second host node, where the first request message is used to request paging the first terminal device; Sending first indication information to the access and mobility management network element corresponding to the first terminal device according to the first request message, where the first indication information indicates paging the first terminal device.

16. The method according to any one of claims 11 to 14, characterized in that, If the second host node is unreachable from the first network element, the method further includes: Sending a paging message to the first terminal device, where the paging message is used to page the first terminal device.

17. The method according to any one of claims 11 to 16, characterized in that, The method further includes: Sending second information to the second host node, where the second information includes the identifiers of the access and mobility management network elements corresponding to each of at least one second terminal device, and / or the identifiers of the access network devices to which each of the second terminal devices was last connected before entering the inactive state; Wherein, the second terminal device is a terminal device in the cell managed by the mobile relay node, and the second terminal device is released to the disconnected state by a third host node, and the third host node includes the host node to which the mobile relay node was connected before connecting to the first host node.

18. A communication method, characterized in that, Applied to the first network element, the method includes: Receiving first information from the first host node; Determining whether the first network element is reachable from the second host node according to the first information; Paging the first terminal device when it is determined that the first network element is unreachable from the second host node; Wherein, the first terminal device is a terminal device managed by the mobile relay node, the mobile relay node has a connection with the first host node, the first terminal device is released to the disconnected state by the first host node, and the second host node is the host node to which the mobile relay node is to be connected.

19. The method according to claim 18, wherein The first network element includes any one of the following: The access and mobility management network element corresponding to the first terminal device, and the access network device to which the first terminal device was last connected before entering the disconnected state.

20. The method according to claim 18 or 19, characterized in that The first information includes the identifier information of the second host node.

21. The method according to claim 20, characterized in that, The paging of the first terminal device includes: Sending a paging message to the first terminal device through the first host node, where the paging message is used to page the first terminal device.

22. A communication method, characterized in that, Applied to the second host node, the method includes: Receiving first information from the first host node; Determining whether the second host node is reachable from the first network element according to the first information; Paging the first terminal device when it is determined that the second host node is unreachable from the first network element; Among them, the first terminal device is a terminal device managed by a mobile relay node. The mobile relay node is connected to the first host node. The first terminal device is released by the first host node to the disconnected state. The second host node is the host node to which the mobile relay node is to be connected.

23. The method according to claim 22, wherein The first network element includes any one of the following: The access and mobility management network element corresponding to the first terminal device, and the access network device to which the first terminal device was last connected before entering the disconnected state.

24. The method according to claim 23, wherein If the first network element is the access and mobility management network element corresponding to the first terminal device, the first information includes the identification information of the access and mobility management network element corresponding to the first terminal device.

25. The method according to any one of claims 22 to 24, characterized in that, Paging the first terminal device includes: Sending a first request message to the first host node, where the first request message is used to request paging the first terminal device.

26. The method according to any one of claims 22 to 25, characterized in that, The method further includes: Receiving second information from the first host node, where the second information includes the identification of the access and mobility management network element corresponding to each of at least one second terminal device, and / or the identification of the access network device to which each of the second terminal devices was last connected before entering the inactive state; Among them, the second terminal device is a terminal device in the cell managed by the mobile relay node. The second terminal device is released by the third host node to the disconnected state. The third host node includes the host node to which the mobile relay node was connected before being connected to the first host node.

27. A communication device, characterized in that, The communication device includes: A processor and a memory. The memory is used to store a computer program. The processor is used to execute the computer program stored in the memory so that the communication device executes the method according to any one of claims 1 to 26.

28. A computer-readable storage medium, characterized in that: A computer program is stored on the computer-readable storage medium. When the computer program runs on a computer, the computer is caused to execute the method according to any one of claims 1 to 26.

29. A computer program product, characterized in that: The computer program product includes a computer program. When the computer program runs on a computer, the computer is caused to execute the method according to any one of claims 1 to 26.

30. A chip system, characterized in that, Including: A processor, configured to call and run a computer program from a memory, so that a communication device equipped with the chip system executes the method according to any one of claims 1 to 26.

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