Communication method and communication apparatus

Abstract

The present application provides a communication method and a communication apparatus. The method comprises: releasing a first terminal device to a non-connected state, the first terminal device being a terminal device managed by a mobile relay node, and there being a connection between the mobile relay node and a first donor node; sending first information to a first network element, the first information indicating to determine whether a second donor node is reachable by the first network element, and the second donor node being a donor node to which the mobile relay node is to be connected. By means of sending to the first network element indication information indicating to determine whether the second donor node is reachable by the first network element, the first network element can page the first terminal device in a timely manner, when it is determined that the second donor node is not reachable by the first network element.

Description

Communication method and communication device

[0001] This application claims priority to the Chinese patent application with application number 202311862562.2 filed with the State Intellectual Property Office of China on December 29, 2023, and priority to the Chinese patent application with the invention name “Communication Method and Communication Device”, all contents of which are incorporated by reference into this application. Technical Field

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

[0003] The fifth generation of mobile communications (5G) introduced integrated access and backhaul (IAB) technology to reduce fiber optic deployment.

[0004] In an IAB communication network, an IAB node can provide wireless access services for terminal devices. For example, service data of a terminal device can be transmitted by the IAB node to an IAB donor via a wireless backhaul link, where the IAB donor can be connected to a core network element serving the terminal device.

[0005] The IAB node can be deployed on a mobile carrier such as a vehicle. In this case, 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 (List) or RAN area code (RANAC) list broadcast by the IAB-DU is related to the current geographic location of the IAB node and may change. The TACList or RANACList is used for UE location management. To save signaling overhead, it is possible to consider keeping the TAC or RANAC broadcast by the IAB-DU unchanged. However, if the TAC / RANAC broadcast by the IAB-DU does not change, for example, the access management network element of an idle terminal residing in the cell under the IAB-DU may be unable to page the terminal. For example, if the IAB node moves to a distant location and the TAC is not changed, the access management network element of the idle terminal may lose connection with the IAB host corresponding to the cell where the terminal resides, resulting in an inability to page the terminal and causing the terminal to lose connection with the network. Therefore, when the IAB node moves, how to timely discover and page the terminal devices managed by the IAB node is an issue that needs to be considered. Summary of the Invention

[0006] The present application provides a communication method and a communication device, which can timely discover and page terminal devices managed by a mobile relay node.

[0007] In a first aspect, a communication method is provided. The method may be executed by a first host node, or may be executed by a component of the first host node (e.g., a chip or circuit), without limitation. For ease of description, the following description uses execution by the first host node as an example.

[0008] The method includes: releasing a first terminal device to a non-connected state, the first terminal device being a terminal device managed by a mobile relay node, and the mobile relay node being connected to the first host node; sending first information to a first network element, the first information indicating whether the first network element and a second host node are reachable, the second host node being the host node to which the mobile relay node is to be connected.

[0009] Based on the above solution, by sending indication information to the first network element to determine whether the first network element and the second host node are reachable, the first network element can page the first terminal device in time when it is determined that the first network element is unreachable with the second host node.

[0010] In combination with the first aspect, in certain implementations 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 most recently connected before entering a non-connected state.

[0011] In combination with the first aspect, in certain implementations of the first aspect, after the first terminal device is released to the non-connected state, an identifier of the access and mobility management network element corresponding to the first terminal device is saved.

[0012] In combination with the first aspect, in some implementations of the first aspect, the first information includes identification information of the second host node.

[0013] In combination with the first aspect, in certain implementations of the first aspect, if the first network element and the second host node are unreachable, a paging message is received from the first network element, where the paging message is used to page the first terminal device; and the paging message is sent to the first terminal device.

[0014] Based on the above solution, when the first network element is unreachable to the second host node, the first network element can page the first terminal device, so that the first terminal device can be discovered in time.

[0015] In combination with the first aspect, in certain implementations of the first aspect, second information is sent to the second host node, and the second information includes an identifier of an access and mobility management network element corresponding to each second terminal device in at least one second terminal device, and / or an identifier of an access network device to which each second terminal device was most recently connected before entering a non-connected state; wherein 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 a non-connected 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.

[0016] Based on the above scheme, 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 and the target host node can interact with the second information to discover the second terminal device in the idle state.

[0017] In combination with the first aspect, in certain implementations of the first aspect, third information is sent to the second network element, and the third information indicates whether the second network element and the second host node 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 most recently connected before entering the non-connected state.

[0018] Based on the above solution, by sending indication information to the second network element to determine whether the second network element and the second host node are reachable, the second network element can page the second terminal device in time when it is determined that the second host node is unreachable.

[0019] In combination with the first aspect, in some implementations of the first aspect, the third information includes identification information of the second host node.

[0020] In combination with the first aspect, in certain implementations of the first aspect, if the second network element is unreachable to the second host node, a paging message is received from the second network element, where the paging message is used to page the second terminal device; and the paging message is sent to the second terminal device.

[0021] In combination with the first aspect, in certain implementations of the first 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 most recently connected before entering the non-connected state is saved.

[0022] In a second aspect, a communication method is provided, in which a first host node sends first information to a second host node indicating whether the second host node is reachable from a first network element. The method can be performed by the first host node, or by a component (e.g., a chip or circuit) of the first host node, without limitation. For ease of description, the following description uses execution by the first host node as an example.

[0023] The method includes: releasing a first terminal device to a non-connected state, the first terminal device being a terminal device managed by a mobile relay node, and the mobile relay node being connected to the first host node; sending first information to a second host node, the first information indicating whether the second host node is reachable to the first network element, and the second host node being the host node to which the mobile relay node is to be connected.

[0024] Based on the above scheme, by sending indication information to the second host node to determine whether the first network element and the second host node are reachable, the second host node can page the first terminal device in time when it is determined that the first network element is unreachable.

[0025] In combination with the second aspect, in certain implementations of the second 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 most recently connected before entering a non-connected state.

[0026] In combination with the second aspect, in certain implementations of the second aspect, if the first network element is the access and mobility management network element corresponding to the first terminal device, after the first terminal device is released to a non-connected state, the identifier of the access and mobility management network element corresponding to the first terminal device is saved.

[0027] In combination with the second aspect, in some implementations of the second aspect, the first information includes identification information of an access and mobility management network element corresponding to the first terminal device.

[0028] In combination with the second aspect, in certain implementations of the second aspect, if the second host node and the first network element are unreachable, a first request message is received from the second host node, and the first request message is used to request paging of the first terminal device; based on the first request message, a first indication message is sent to the access and mobility management network element corresponding to the first terminal device, and the first indication message indicates paging of the first terminal device.

[0029] Based on the above solution, when the first network element and the second host node are unreachable, the second host node can initiate a request message to page the first terminal device, thereby paging the first terminal device.

[0030] In combination with the second aspect, in certain implementations of the second aspect, if the second host node is unreachable to the first network element, a paging message is sent to the first terminal device, and the paging message is used to page the first terminal device.

[0031] Based on the above solution, when the first network element and the second host node are unreachable, the first host node can page the first terminal device, so that the first terminal device can be discovered in time.

[0032] In combination with the second aspect, in certain implementations of the second aspect, second information is sent to the second host node, and the second information includes an identifier of an access and mobility management network element corresponding to each second terminal device in at least one second terminal device, and / or an identifier of an access network device to which each second terminal device was most recently connected before entering an inactive state; wherein 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 a non-connected 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.

[0033] Based on the above scheme, 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 and the target host node can interact with the second information to discover the second terminal device in the idle state.

[0034] In combination with the second aspect, in certain implementations of the second aspect, third information is sent to the second host node, and the third information indicates whether 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 most recently connected before entering the non-connected state.

[0035] Based on the above solution, by sending indication information to the second host node to determine whether the second network element and the second host node are reachable, the second host node can page the second terminal device in time when it is determined that the second network element is unreachable.

[0036] In combination with the second aspect, in certain 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 identification information of the access and mobility management network element corresponding to the second terminal device.

[0037] In combination with the second aspect, in certain implementations of the second aspect, if the second host node and the second network element are unreachable, a second request message is received from the second host node, and the second request message is used to request paging of the second terminal device; according to the second request message, a second indication information is sent to the access and mobility management network element corresponding to the second terminal device, and the second indication information indicates paging of the second terminal device.

[0038] Based on the above solution, when the second network element is unreachable to the second host node, the second host node can initiate a request message to page the second terminal device, thereby paging the second terminal device.

[0039] In combination with the second aspect, in certain implementations of the second aspect, if the second host node is unreachable to 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.

[0040] Based on the above solution, when the second network element is unreachable to the second host node, the first host node can page the second terminal device, so that the second terminal device can be discovered in time.

[0041] In combination with the second aspect, in certain 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 most recently connected before entering the non-connected state is saved.

[0042] In a third aspect, a communication method is provided. The method may be executed by a first network element, or by a component of the first network element (e.g., a chip or circuit), without limitation. For ease of description, the following description is based on an example of execution by the first network element.

[0043] The method includes: receiving first information from a first host node; determining whether the first network element and the second host node are reachable based on the first information; and paging a first terminal device when it is determined that the first network element and the second host node are unreachable; 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 to a non-connected state by the first host node, and the second host node is the host node to be accessed by the mobile relay node.

[0044] Based on the above scheme, by receiving an indication from the first host node to determine whether the first network element and the second host node are reachable, the first network element can page the first terminal device in time when it is determined that the first network element is unreachable with the second host node.

[0045] In combination with the third aspect, in certain implementations of the third aspect, the first network element includes any one of the following: an access and mobility management network element corresponding to the first terminal device, and an access network device to which the first terminal device was most recently connected before entering a non-connected state.

[0046] In combination with the third aspect, in certain implementations of the third aspect, the first information includes identification information of the second host node.

[0047] In combination with the third aspect, in certain 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.

[0048] In a fourth aspect, a communication method is provided. This method can be executed by a second host node, or by a component of the second host node (e.g., a chip or circuit), without limitation. For ease of description, the following description uses execution by the second host node as an example.

[0049] The method includes: receiving first information from a first host node; determining whether the second host node and the first network element are reachable based on the first information; and paging a first terminal device when it is determined that the second host node and the first network element are unreachable; 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 to a non-connected state by the first host node, and the second host node is the host node to be accessed by the mobile relay node.

[0050] Based on the above scheme, by receiving an indication from the first host node to determine whether the first network element and the second host node are reachable, the second host node can page the first terminal device in time when it is determined that the first network element is unreachable.

[0051] In combination with the fourth aspect, in certain implementations 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 most recently connected before entering a non-connected state.

[0052] In combination with the fourth aspect, in certain implementations of the fourth aspect, if the first network element is the 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.

[0053] In combination with the fourth aspect, in certain implementations of the fourth aspect, a first request message is sent to the first host node, where the first request message is used to request paging of the first terminal device.

[0054] In combination with the fourth aspect, in certain implementations of the fourth aspect, second information is received from the first host node, and the second information includes an identifier of an access and mobility management network element corresponding to each second terminal device in at least one second terminal device, and / or an identifier of an access network device to which each second terminal device was most recently connected before entering an inactive state; wherein 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 a non-connected 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.

[0055] In combination with the fourth aspect, in certain implementations of the fourth aspect, third information is received from the first host node, and the third information indicates 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 most recently connected before entering the non-connected state; when it is determined that the second host node and the second network element are unreachable, the second terminal device is paged.

[0056] In combination with the fourth aspect, in certain 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 identification information of the access and mobility management network element corresponding to the second terminal device.

[0057] In combination with the fourth aspect, in certain implementations of the fourth aspect, if the second host node is unreachable to the second network element, a second request message is sent to the first host node, where the second request message is used to request paging of the second terminal device.

[0058] In a fifth aspect, a communication device is provided. The device includes a processing unit and a transceiver unit, the processing unit being configured to release a first terminal device to a non-connected state, the first terminal device being a terminal device managed by a mobile relay node connected to the device; and the transceiver unit being configured to send first information to a first network element, the first information indicating whether the first network element is reachable from a second host node to which the mobile relay node is to be connected.

[0059] In combination with the fifth aspect, in certain implementations of the fifth 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 most recently connected before entering a non-connected state.

[0060] In combination with the fifth aspect, in certain implementations of the fifth aspect, after releasing the first terminal device to the non-connected state, the processing unit is further used to save the identifier of the access and mobility management network element corresponding to the first terminal device.

[0061] In combination with the fifth aspect, in certain implementations of the fifth aspect, the first information includes identification information of the second host node.

[0062] In combination with the fifth aspect, in certain implementations of the fifth aspect, if the first network element and the second host node are unreachable, the transceiver unit is also used to receive a paging message from the first network element, which is used to page the first terminal device; and send the paging message to the first terminal device.

[0063] In combination with the fifth aspect, in certain implementations of the fifth aspect, the transceiver unit is also used to send second information to the second host node, and the second information includes an identifier of an access and mobility management network element corresponding to each second terminal device in at least one second terminal device, and / or an identifier of the access network device to which each second terminal device was most recently connected before entering a non-connected state; wherein 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 a non-connected 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 device.

[0064] In combination with the fifth aspect, in certain implementations of the fifth aspect, the transceiver unit is also used to send third information to the second network element, and the third information indicates whether the second network element and the second host node 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 most recently connected before entering the non-connected state.

[0065] In combination with the fifth aspect, in certain implementations of the fifth aspect, the third information includes identification information of the second host node.

[0066] In combination with the fifth aspect, in certain implementations of the fifth aspect, if the second network element and the second host node are unreachable, the transceiver unit is also used to: receive a paging message from the second network element, which is used to page the second terminal device; and send the paging message to the second terminal device.

[0067] In combination with the fifth aspect, in certain implementations of the fifth aspect, the processing unit is also used 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 most recently connected before entering the non-connected state.

[0068] In the sixth aspect, a communication device is provided, which includes a transceiver unit and a processing unit. The processing unit is used to release a first terminal device to a non-connected state. 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; the transceiver unit is used to send first information to a second host node, and the first information indicates whether the second host node and the first network element are reachable. The second host node is the host node to which the mobile relay node is to be connected.

[0069] In combination with the sixth aspect, in certain implementations of the sixth 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 most recently connected before entering a non-connected state.

[0070] In combination with the sixth aspect, in certain 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 a non-connected state, the processing unit is also used to save the identifier of the access and mobility management network element corresponding to the first terminal device.

[0071] In combination with the sixth aspect, in certain implementations of the sixth aspect, the first information includes identification information of an access and mobility management network element corresponding to the first terminal device.

[0072] In combination with the sixth aspect, in certain implementations of the sixth aspect, if the second host node and the first network element are unreachable, the transceiver unit is specifically used to receive a first request message from the second host node, and the first request message is used to request paging of 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, and the first indication message indicates paging of the first terminal device.

[0073] In combination with the sixth aspect, in certain implementations of the sixth aspect, if the second host node is unreachable to the first network element, the transceiver unit is specifically used to send a paging message to the first terminal device, and the paging message is used to page the first terminal device.

[0074] In combination with the sixth aspect, in certain implementations of the sixth aspect, the transceiver unit is also used to send second information to the second host node, and the second information includes an identifier of an access and mobility management network element corresponding to each second terminal device in at least one second terminal device, and / or an identifier of an access network device to which each second terminal device was most recently connected before entering an inactive state; wherein 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 a non-connected 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.

[0075] In combination with the sixth aspect, in certain implementations of the sixth aspect, the transceiver unit is also used to send third information to the second host node, and the third information indicates whether 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 most recently connected before entering the non-connected state.

[0076] In combination with the sixth aspect, in certain 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 identification information of the access and mobility management network element corresponding to the second terminal device.

[0077] In combination with the sixth aspect, in certain implementations of the sixth aspect, if the second host node and the second network element are unreachable, the transceiver unit is also used to: receive a second request message from the second host node, the second request message being used to request paging of the second terminal device; and send a second indication message to the access and mobility management network element corresponding to the second terminal device according to the second request message, the second indication message indicating paging of the second terminal device.

[0078] In combination with the sixth aspect, in certain implementations of the sixth aspect, if the second host node is unreachable to the second network element, the transceiver unit is further used to send a second paging message to the second terminal device, and the second paging message is used to page the second terminal device.

[0079] In combination with the sixth aspect, in certain implementations of the sixth aspect, the processing unit is also used 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 most recently connected before entering the non-connected state.

[0080] In the seventh aspect, a communication device is provided, which includes a transceiver unit and a processing unit, the transceiver unit is used to receive first information from a first host node; the processing unit is used to determine whether the first network element and the second host node are reachable based on the first information; when it is determined that the first network element and the second host node are unreachable, the processing unit is also used 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 to a non-connected state by the first host node, and the second host node is the host node to be accessed by the mobile relay node.

[0081] In combination with the seventh aspect, in certain implementations of the seventh 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 most recently connected before entering a non-connected state.

[0082] In combination with the seventh aspect, in certain implementations of the seventh aspect, the first information includes identification information of the second host node.

[0083] In combination with the seventh aspect, in certain implementations of the seventh aspect, the transceiver unit is further used to send a paging message to the first terminal device through the first host node, and the paging message is used to page the first terminal device.

[0084] In the eighth aspect, a communication device is provided, which includes a transceiver unit and a processing unit, the transceiver unit is used to receive first information from a first host node; the processing unit is used to determine whether the second host node and the first network element are reachable based on the first information; when it is determined that the second host node and the first network element are unreachable, the processing unit is also used to page the 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 to a non-connected state by the first host node, and the second host node is the host node to be accessed by the mobile relay node.

[0085] In combination with the eighth aspect, in certain implementations 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 most recently connected before entering a non-connected state.

[0086] In combination with the eighth aspect, in certain implementations of the eighth aspect, if the first network element is the 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.

[0087] In combination with the eighth aspect, in certain implementations of the eighth aspect, the transceiver unit is specifically used to send a first request message to the first host node, where the first request message is used to request paging of the first terminal device.

[0088] In combination with the eighth aspect, in certain implementations of the eighth aspect, the transceiver unit is also used to receive second information from the first host node, the second information including an identifier of an access and mobility management network element corresponding to each second terminal device in at least one second terminal device, and / or an identifier of an access network device to which each second terminal device was most recently connected before entering an inactive state; wherein 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 a non-connected 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.

[0089] In combination with the eighth aspect, in certain implementations of the eighth aspect, the transceiver unit is also used to receive third information from the first host node, and the third information indicates 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 most recently connected before entering the non-connected state; when it is determined that the second host node and the second network element are unreachable, the processing unit is also used to page the second terminal device.

[0090] In combination with the eighth aspect, in certain 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 identification information of the access and mobility management network element corresponding to the second terminal device.

[0091] In combination with the eighth aspect, in certain implementations of the eighth aspect, if the second host node and the second network element are unreachable, the transceiver unit is further used to send a second request message to the first host node, and the second request message is used to request paging of the second terminal device.

[0092] In a ninth aspect, a communication device is provided, the device being configured to execute the method of any possible implementation of the first to fourth aspects. Specifically, the device may include units and / or modules, such as a processing unit and / or a transceiver unit, for executing the method of any possible implementation of the first to fourth aspects.

[0093] In one implementation, the apparatus is a communication device (e.g., a first host node, a first network element, or a second host node). When the apparatus 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. Alternatively, the transceiver may be a transceiver circuit. Alternatively, the input / output interface may be an input / output circuit.

[0094] In another implementation, the apparatus is a chip, chip system, or circuit for a communication device (such as a first host node, a first network element, or a second host node). When the apparatus is a chip, chip system, or circuit for a communication device, the communication unit may be an input / output interface, interface circuit, output circuit, input circuit, pin, or related circuit on the chip, chip system, or circuit; and the processing unit may be at least one processor, processing circuit, or logic circuit.

[0095] In a tenth aspect, a communication device is provided, comprising: at least one processor for executing a computer program or instruction stored in a memory to perform a method in any possible implementation of the first to fourth aspects above.

[0096] Optionally, the device further comprises a memory for storing computer programs or instructions. Optionally, the device further comprises a communication interface, and the processor reads the computer programs or instructions stored in the memory through the communication interface.

[0097] In one implementation, the apparatus is a communication device (such as a first host node, a first network element, or a second host node).

[0098] In an eleventh aspect, a processor is provided for executing the method in any possible implementation of the first to fourth aspects above.

[0099] For the operations such as sending and acquiring / receiving involved in the processor, unless otherwise specified, or if they do not conflict with their actual functions or internal logic in the relevant descriptions, they can be understood as operations such as processor output and input, or as sending and receiving operations performed by the radio frequency circuit and antenna. This application does not limit this.

[0100] In a twelfth aspect, a communication system is provided, comprising at least one of the aforementioned first host node, first network element or second host node.

[0101] In a thirteenth aspect, a computer-readable storage medium is provided, which stores a program code executed by a user device, and the program code includes a method for executing any possible implementation of the first to fourth aspects above.

[0102] In a fourteenth aspect, a computer program product comprising instructions is provided, which, when run on a computer, enables the computer to execute the method in any possible implementation of the first to fourth aspects above. BRIEF DESCRIPTION OF THE DRAWINGS

[0103] FIG1 is a diagram of the communication network architecture of the integrated access and backhaul provided in this application.

[0104] FIG2 is a diagram of a system architecture applicable to an embodiment of the present application.

[0105] FIG3 is a schematic diagram of relay node migration according to an example embodiment of the present application.

[0106] FIG4 is a flow chart of a communication method 400 provided in this application.

[0107] FIG5 is a flow chart of a communication method 500 provided in this application.

[0108] FIG6 is a schematic structural diagram of a communication device 600 provided in an embodiment of the present application.

[0109] FIG7 is a schematic structural diagram of a communication device 700 provided in an embodiment of the present application. DETAILED DESCRIPTION

[0110] The technical solution in this application will be described below with reference to the accompanying drawings.

[0111] The technical solutions of the embodiments 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) system, universal mobile telecommunication system (UMTS), world-wide interoperability for microwave access (WiMAX) communication system, fifth generation (5G) system or future evolved communication system, vehicle-to-X (V2X), where V2X may include vehicle to network (V2N), vehicle to vehicle (V2V), and vehicle to infrastructure (V2I). infrastructure (V2I), vehicle to pedestrian (V2P), 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.

[0112] 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 dual connectivity (DC), multi-connectivity (MC) and other scenarios, and this application does not impose any restrictions on this.

[0113] FIG1 is a diagram of the communication network architecture of the integrated access and backhaul provided in this application.

[0114] As shown in Figure 1, the IAB network includes an access link and a backhaul link, and the terminal device is connected to the IAB host through an IAB node. In the IAB network, one or more IAB nodes can be included on a transmission path between the terminal device and the IAB host. Each IAB node needs to maintain a wireless backhaul link to 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 wireless access link is between the IAB node and the child node (i.e., the terminal device). If the child node of the IAB node is another IAB node, the wireless backhaul link is between the IAB node and the child node (i.e., the other IAB node).

[0115] The IAB host can be an access network element with complete base station functions, or an access network element with a centralized unit (CU) and a distributed unit (DU) separated. The IAB host is connected to the core network element (such as the 5G core network) serving the terminal device and provides wireless backhaul functions for the IAB node.

[0116] An IAB node can consist of a mobile termination (MT) and a distributed unit (DU). When the IAB node faces its parent node, it can act as a terminal device, that is, the role of an MT. When the IAB node 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, the role of a DU.

[0117] For ease of description, the centralized unit of the IAB host is referred to as the host CU, and the distributed unit of the IAB host is referred to as the host DU. The host CU can be in a form with a separate control plane (CP) and user plane (UP). For example, the host CU can be composed of a CU-CP and one (or more) CU-UPs.

[0118] IAB introduces a new protocol layer in the wireless backhaul link - the backhaul adaptation protocol (BAP) layer. This protocol layer is located above the radio link control (RLC) layer and can be used to implement data packet routing in the wireless backhaul link and bearer mapping and other functions.

[0119] An F1 interface (or F1* interface, which may be collectively referred to as F1 interface in this article, but the name is not limited) needs to be established between the IAB node (the DU part of the IAB) and the host node (or host CU). This interface supports user plane protocols (F1-U / F1*-U) and control plane protocols (F1-C / F1*-C).

[0120] FIG2 is a diagram of a system architecture applicable to an embodiment of the present application.

[0121] As shown in Figure 2, the DU portion of the IAB node (i.e., the IAB-node-DU shown in Figure 2, collectively referred to as the IAB-DU below) is logically connected to the IAB-donor-CU (i.e., the IAB-host-CU shown in Figure 2) via the F1 interface. In other words, the F1 connection in Figure 2 is not a physical direct connection, but a logical connection. In practice, the F1 connection between the IAB-DU and the IAB-donor-CU is physically implemented via the NR Uu interface between the MT of each IAB node and the DU of its parent node. However, because the IAB-DU can ultimately communicate with the IAB-donor-CU, it can be considered that a logical F1 interface exists between the IAB-DU and the IAB-donor-CU. The F1 interface supports the user plane protocol (F1-U) and the control plane protocol (F1-C). The F1-U includes one or more of the following protocol layers: the general packet radio service tunneling protocol user plane (GTP-U), the user datagram protocol (UDP), and the internet protocol (IP). The F1-C includes one or more of the following: the F1 application protocol (F1AP), the stream control transport protocol (SCTP), and the IP layer.

[0122] The terminal device in the embodiments of the present application may refer to user equipment (UE), access terminal, user unit, user station, mobile station, mobile station, remote station, remote terminal, mobile device, user terminal, wireless communication device, user agent or user device. The terminal in the embodiments of the present application can be a mobile phone, a tablet computer, 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 a smart grid, a wireless terminal in transportation safety, a wireless terminal in a smart city, a wireless terminal in a 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 device connected to a wireless modem, a vehicle-mounted device, a wearable device, a terminal in a 5G network or a terminal in a future evolution network, etc.

[0123] Wearable devices, also known as wearable smart devices, are a general term for wearable devices that use wearable technology to intelligently design and develop wearable devices for daily wear, such as glasses, gloves, watches, clothing, and shoes. Wearable devices are portable devices that are worn directly on the body or integrated into the user's clothing or accessories. Wearable devices are not just hardware devices, but also achieve powerful functions through software support, data interaction, and cloud interaction. In a broad sense, wearable smart devices include those that are fully functional, large in size, and can achieve full or partial functions without relying on smartphones, such as smart watches or smart glasses, as well as those that only focus on a certain type of application function and need to be used in conjunction with other devices such as smartphones, such as various smart bracelets and smart jewelry for vital sign monitoring.

[0124] The host node in the embodiment of the present application includes but is not limited to an IAB host node, and the IAB host node includes but is not limited to an evolved node B (eNB), a radio network controller (RNC), a node B (NB), a radio network controller (RNC), a base station controller (BSC), a base transceiver station (BTS), a home base station (e.g., home evolved node B, or home node B, HNB), a base band unit (BBU), an access point (AP) in a wireless fidelity (WIFI) system, a wireless relay node, a wireless backhaul node, a transmission point (TP), or a transmission and reception point (TP) The IAB host node may include a baseband unit (CU) and a distributed unit (DU). In some deployments, the IAB host node may include a CU and a DU, or the IAB host node may be a radio access network (RAN) device including a CU node and a DU node.

[0125] It should be understood that the IAB host, IAB node, and terminal devices in the embodiments of this application can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; on water; or in the air on aircraft, balloons, and satellites. The embodiments of this application do not limit the application scenarios of the IAB host, IAB node, and terminal devices.

[0126] The IAB node in the embodiment of the present application, that is, the relay device (node) may be a terminal device. For specific examples, refer to the above enumeration of terminal devices, which will not be described in detail here.

[0127] It should be noted that Figures 1 and 2 are only examples and do not constitute a limitation of the present application. A person skilled in the art will know that with the evolution of network architecture and the emergence of new business scenarios, the technical solutions provided in this application are also applicable to similar technical problems.

[0128] When an IAB node is deployed on a movable carrier such as a vehicle, the IAB node can be called a mobile IAB node (i.e., a movable IAB node) or a mobile relay node (RN), which are collectively referred to as mobile relay nodes in the following text. The following describes the partial migration process of the relay node and the complete migration process of the mobile relay node.

[0129] FIG3 is a schematic diagram of relay node migration according to an example embodiment of the present application.

[0130] Figure 3 (a) is a schematic diagram of a partial migration of a relay node according to an embodiment of the present application. As shown in Figure 3 (a), the IAB node that undergoes migration is called a boundary node, such as the mobile IAB node in the figure, which is denoted as the mAB node. Before the partial migration, there is an RRC connection between the mAB-MT and CU1; there is an F1 interface between the mAB-DU and CU1, which is connected via the source path. During partial migration, the mAB-MT undergoes cross-CU cell switching and establishes an RRC connection with the host-CU2. At this time, in order to avoid introducing the F1 interface re-establishment process, the mAB-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 mAB-DU and the host-CU1 becomes a cross-topology path: Host-CU1 and Host-CU2 can be referred to as the F1-terminating CU and non-F1-terminating CU (or RRC terminating CU), respectively, or as the source CU and target CU, respectively. It's important to note that data transmitted across the topology path does not pass through Host-CU2; Host-CU1 and Donor-DU2 communicate directly over the IP network.

[0131] 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 the establishment, it replies with an IAB transport migration management response message to the F1 terminating CU; if the non-F1-terminating CU disagrees to the establishment, it replies with an IAB transport migration management reject message to the F1 terminating CU. If the F1 terminating CU or the non-F1-terminating CU subsequently wants to modify or withdraw the quality of service (QoS) of the flow, they can also exchange IAB transport migration modification request / response messages.

[0132] Figure 3(b) shows a schematic diagram of consecutive partial migration of relay nodes. As shown in Figure 3(b), mAB-MT switches from CU2 to CU3, and the F1 interface of DU is always associated with CU1. In Figure 3(b), the mAB node is directly connected to the host-DU, but this is not limited. There may be other IAB nodes between the mAB node and the host-DU. In addition, it is not limited how the mAB-MT reaches the host-CU2. For example, the mAB-MT may be switched from the host-CU1 to the host-CU2 (as shown in Figure 3(a)), but it may also be switched from other CUs to the host-CU2.

[0133] Figure 3 (c) shows a schematic diagram of DU migration. Taking into account the mobility of the IAB node or the need for load balancing on the RAN side, the IAB node can trigger the DU migration process by the host CU terminated by the source F1 or OAM, that is, migrating the F1 connection of the mAB-DU from the host CU terminated by the source F1 to the host CU terminated by the target F1. As shown in Figure 3 (c), the mAB node includes two logical DUs, that is, the mAB-DU includes mAB-DUa and mAB-DUb. The mIAB-DU initially establishes an F1 connection with the host-CU1 through the mAB-DUa. The host-CU1 is the source F1-terminating Donor-CU. At this time, the mAB-DUb is in a waiting state. The mIAB-MT is connected to the host-CU2 through RRC. The host-CU2 is the non-F1 terminated host CU. After the move, the mIAB-DUb can be triggered by the host-CU1 or OAM to establish a new F1 connection with the host-CU3, which is the target F1-terminating donor-CU.

[0134] It can be understood that mIAB-DUa and mIAB-DUb can be regarded as two different DUs, each with an F1 interface. After the mIAB node completes DU migration, the terminal device needs to perform a handover from the cell managed by mIAB-DUa to the cell managed by mIAB-DUb.

[0135] Hereinafter, the host-CU is abbreviated as host CU, for example, host-CU1 is abbreviated as host CU1, host-CU2 is abbreviated as host CU2, and so on.

[0136] It should be noted that the host CUs in Figures 2 and 3 are only examples. In actual deployment, host CU1 and host CU2 can be the same CU, or host CU2 and host CU3 can be the same CU. This application does not impose any restrictions on this.

[0137] The following describes the tracking area (TA) related to the embodiments of the present application.

[0138] TA is a concept introduced by the LTE / NR system for UE location management. 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 to the network, the core network assigns a UE registration area (RA) to each UE. The RA may contain a tracking area identity list (TAI List). TAI may consist 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.

[0139] The core network's paging (CN Paging) range for the UE can be determined based on the TAI. For example, when a service for UE#1 arrives on the core network side, if UE#1 is in the idle state, the core network (e.g., an AMF connected to a RAN in the TAI List, such as an NG interface connection) can send a paging message to the RAN in UE#1's current RA. The 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 and transmits services. That is, when the core network initiates paging for UE#1, it needs to know the TAI List corresponding to UE#1's current location. When a UE in the idle state moves to a cell that does not belong to the TAI List, the UE will initiate a tracking area update (TAU) process, actively access the network, and return to the connected state; the core network determines the UE's current location and updates the UE's RA, that is, reallocates the TAI List corresponding to the TA to which the UE's current cell belongs. In addition to the case where the UE moves out of the TAI List, the UE can also perform the TAU procedure regularly to enable the core network to know the UE's location.

[0140] Similarly, the RAN can also assign a RAN area code list (RANAC List) to the UE for location management of inactive UEs on the RAN side. For example, when a service arrives for UE#2 (UE#2 is in the inactive state) on the core network side, the core network can assume that UE#2 is still in the connected state under the last serving gNB (the last serving gNB) and send UE#2's service data to the last serving gNB. Knowing that UE#2 is in the inactive state, the last serving gNB, after receiving UE#2's service data from the core network, sends a paging message (RAN Paging) to the gNBs within the RANAC List that have an Xn interface with UE#2. This paging message carries UE#2's identity, enabling all gNBs within the RANAC List that have an Xn interface with UE#2 to locate UE#2. After receiving the paging message broadcast by the gNB with an Xn interface with UE#2 and carrying UE#2's identity, UE#2 returns from the inactive state to the connected state and resumes service transmission. Similar to TAU, when an inactive UE moves out of a cell on the RANAC List, it can perform a RAN-based notification area update (RNAU) to return to the connected state. At this point, the UE's last serving gNB is the current serving gNB, which reassigns the RANAC List to the UE. The UE can also periodically perform RNAUs to keep the core network informed of the UE's location.

[0141] In an IAB communication network, the TAC / RANAC broadcast by the DU (denoted as mIAB-DU) of a mobile relay node is related to the current geographical location of the mIAB node and may change. To save signaling overhead, it is possible to consider keeping the TAC / RANAC broadcast by the mIAB-DU unchanged.

[0142] Taking TAC as an example, if the TAC broadcast by the mAB-DU does not change, the AMF of an idle UE residing in the cell under the mAB-DU may be unable 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 TAI List, the AMF will send a paging message to the RAN in the TAI List. If the mAB node moves to a distant place and the TAC is not changed at this time, the AMF may lose connection with the host CU corresponding to the cell where the UE resides, which in turn causes the AMF to be unable to page the UE, causing the UE to lose connection with the network.

[0143] For example, in the DU migration scenario shown in (c) of Figure 3, 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 before the UE enters 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.

[0144] 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.

[0145] For example, in Figure 3(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, resulting in Host-CU1 being unable to page the UE in Host-CU3 through RAN Paging. Therefore, if the TAC / RANAC broadcast by the mIAB-DU does not change, how to discover and page the UE in the TAI List and / or RANAC List is a problem that needs to be considered.

[0146] 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.

[0147] Figure 4 is a flow chart of a communication method 400 provided by the present application. The method 400 illustrated in Figure 4 can be applied to the DU migration scenario illustrated in Figure 3. The method includes the following steps.

[0148] S410: The first host node releases the first terminal device to a disconnected state.

[0149] The first terminal device is a terminal device in a cell managed by a mobile relay node. For example, the mobile relay node can refer to the above description of the mobile IAB node (ie, a mobile IAB node).

[0150] The first host node can be understood as the source host node of the mobile relay node, and a connection exists between the mobile relay node and the first host node. For example, an RRC connection exists between the mobile equipment of the mobile relay node and the CU of the first host node; and / or an F1 interface exists between the DU of the mobile relay node and the CU of the first host node.

[0151] For example, the first host node may release at least one terminal device managed by the mobile relay node to a non-connected state based on 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 may include an idle state or an inactive state.

[0152] Optionally, the method further includes:

[0153] S420, the first host node saves the identification information of the access and mobility management network element corresponding to the first terminal device.

[0154] Exemplarily, after the first host node releases the first terminal device to a non-connected state, the first host node saves identification information of the access and mobility management network element corresponding to the first terminal device.

[0155] 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 to the first terminal device.

[0156] For example, the identification information of the access and mobility management network element may be the ID of the access and mobility management network element or the IP address of the access and mobility management network element.

[0157] Optionally, the first host node may further store the identifier of the first terminal device; or in other words, the first host node may store the correspondence between the identifier of the first terminal device and the identifier of the access and mobility management network element.

[0158] Exemplarily, the identifier of the first terminal device includes but is not limited to the following identifiers:

[0159] UE's paging radio network temporary identity (P-RNTI), cell radio network temporary identity (C-RNTI), user permanent identifier (SUPI), user concealed identifier (SUCI), generic public subscription identifier (GPSI), permanent equipment identifier (PEI) or (mobile subscriber international ISDN / PSTN number, MSISDN), where ISDN is the integrated service digital network and PSTN is the public switched telephone network.

[0160] S430: The first host node sends first information to a first network element. Correspondingly, the first network element receives the first information from the first host node.

[0161] The first information indicates whether the first network element is reachable to 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.

[0162] Exemplarily, when it is determined 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.

[0163] Exemplarily, whether the first network element and the second host node are reachable can be understood as whether an NG interface exists or can be established between the first network element and the second host node; or whether the IP between the first host node and the second host node is reachable (i.e., whether the IP address is reachable).

[0164] Among them, the first network element can 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 non-connected state.

[0165] Exemplarily, when the first network element is an 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 via a (protocol for NG interface, NGAP) message.

[0166] The first information may include identification information of the second donor node. For example, the identification information may be a gNB ID of the second donor node or an IP address of the second donor node.

[0167] Optionally, the first information may also carry an identifier of the first terminal device.

[0168] S440: The first network element determines whether the first network element and the second host node are reachable based on the first information.

[0169] Specifically, the first network element may determine the second host node according to the first information, and further determine whether the first network element and the second host node are reachable.

[0170] Exemplarily, the first network element determines whether the first network element and the second host node are reachable by determining whether an NG interface exists between the first network element and the second host node, or whether an NG interface can be established.

[0171] Alternatively, in a case where the first information carries the IP address of the second host node, the first network element may determine whether it is reachable to the second host node by determining whether the IP address of the second host node is reachable.

[0172] It should be understood that if the first network element is an access and mobility management network element, and there is no NG interface between the first network element and the second host node or an NG interface connection cannot be established, then the first network element and the second host node are unreachable; otherwise, the first network element and the second host node are reachable.

[0173] Alternatively, if the first network element is an access network device, there is no Xn interface between the first network element and the second host node or an Xn interface connection cannot be established, then the first network element and the second host node are unreachable; otherwise, the first network element and the second host node are reachable.

[0174] 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 unreachable.

[0175] It should be understood that the above NG interface and Xn interface are only an example of the communication interface between the first host node and the access and mobility management network element, and the communication interface between the first host node and the access network device. This application does not limit this. For example, in different communication systems, the communication interface can also be other interfaces or the communication interface can also be other names.

[0176] Optionally, when it is determined that the first network element and the second host node are unreachable, if the first network element is an access and mobility management network element corresponding to the first terminal device, subsequent steps can be divided into two cases:

[0177] Case 1:

[0178] The first network element sends a paging message to the first donor node. Correspondingly, the first donor node receives the paging message from the first network element.

[0179] The paging message is used to page the first terminal device. The paging message can refer to the CN Paging message above.

[0180] Furthermore, the method further includes: the first host node sending the paging message to the first terminal device. Correspondingly, the first terminal device receives the paging message from the first host node.

[0181] 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 an idle state to a connected state.

[0182] Case 2:

[0183] The first network element redefines the registration area RA of the first terminal device.

[0184] Exemplarily, the first network element redetermines a TAC List corresponding to the first terminal device, and the TAC List may include the TAC where the second host node is located.

[0185] In this case, when the first terminal device subsequently establishes a connection with the second host node, the core network can page the first terminal device back to the connected state based on the updated RA of the first terminal device.

[0186] Optionally, when it is determined that the first network element and the second host node are unreachable, if the first network element is the access network device to which the first terminal device was most recently connected before entering the disconnected state (the access network device to which the first terminal device was most recently connected is the first host node), the subsequent steps may include:

[0187] Case 3:

[0188] 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.

[0189] 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 can refer to the RAN Paging above. 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 can 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.

[0190] Case 4:

[0191] The first donor node redetermines the RANAC List of the first terminal device.

[0192] Exemplarily, the RANAC List corresponding to the first terminal device re-determined by the first donor node may include the RANAC corresponding to the second donor node.

[0193] In this case, when the first terminal device subsequently establishes a connection with the second host node, the second host node can page the first terminal device back to the connected state based on the updated RANAC List of the first terminal device.

[0194] It should be understood that the above steps can also be used to process other terminal devices released by the first host node back to the non-connected state. That is, the above steps can 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 can discover the other terminal devices.

[0195] Optionally, the method further includes:

[0196] 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.

[0197] 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 most recently connected before entering the non-connected state.

[0198] Optionally, the second information may also 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).

[0199] 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 a non-connected state by a third host node, where the third host node includes a 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.

[0200] For example, when the third host node releases the second terminal device managed by the mobile relay node and returns it to a non-connected state, the third host node can 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 that was most recently connected to the first host node.

[0201] Based on the above scheme, by sending the second information to the second node, when the mobile relay node moves to the target host node, the second host node can interact with the target host node through the second information to discover the second terminal device in the idle state.

[0202] Optionally, the method further includes:

[0203] 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.

[0204] Among them, the third information indicates 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 to which the second terminal device was most recently connected before entering the non-connected state.

[0205] 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.

[0206] The third information includes identification information of the second host node. The identification information of the second host node can refer to the description in S430.

[0207] Optionally, the method further includes:

[0208] The second network element determines whether the second network element and the second host node are reachable based on the third information. The specific method for determining whether the second network element and the second host node are reachable can refer to the description in S440.

[0209] 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:

[0210] 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 to the second terminal device can refer to the first case in S440.

[0211] Optionally, the second network element may also update the RA of the second terminal device. For details, please refer to the second case in S440.

[0212] Optionally, when it is determined that the second network element is unreachable from the second host node, if the second network element is the most recently connected access network device, the method further includes:

[0213] The access network device sends the paging message to the second terminal device. Accordingly, the second terminal device receives the paging message from the first host node. The second terminal device returns to a connected state based on the paging message. For details, see Situation 3 in S440. Optionally, the access network device re-determines the RANAC List for the second terminal device. For details, see Situation 4 in S440.

[0214] Figure 5 is a flow chart of a communication method 500 provided by the present application. The method 500 illustrated in Figure 5 can be applied to the DU migration scenario illustrated in Figure 3. The method includes the following steps.

[0215] S510: The first host node releases the first terminal device to a disconnected state.

[0216] Among them, the first terminal device is a terminal device in the cell managed by the mobile relay node; 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; the first terminal device is one of the at least one terminal device; the non-connected state can include an idle state or an inactive state.

[0217] For details of this step, please refer to the description in S410.

[0218] Optionally, the method further includes:

[0219] S520, the first host node saves the identification information of the access and mobility management network element corresponding to the first terminal device.

[0220] Exemplarily, after the first host node releases the first terminal device to a non-connected state, the first host node saves identification information of the access and mobility management network element corresponding to the first terminal device.

[0221] Optionally, the first host node may further store the identifier of the first terminal device; or the first host node may store 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.

[0222] 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.

[0223] The first information indicates whether the second host node and the first network element are reachable.

[0224] The first network element may be 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 most recently connected before entering the disconnected state. If the first network element may be an access and mobility management network element corresponding to the first terminal device, the first information may include an identifier of the access and mobility management network element.

[0225] Optionally, the first information may also carry an identifier of the first terminal device.

[0226] S540: The second host node determines whether it is reachable to the first network element according to the first information.

[0227] Specifically, the second host node can determine the first network element based on the first information, and then determine whether it is reachable with the first network element. The specific manner in which the second host node determines whether it is reachable with the first network element can refer to the manner in which the first network element determines whether it is reachable with the second host node in S440.

[0228] Optionally, when it is determined that the first network element is unreachable, the method further includes:

[0229] The second host node sends a request message (recorded as request message #1) to the first host node. The request message #1 is used to request paging of the first terminal device. The request message #1 may carry an identifier of the first terminal device.

[0230] Correspondingly, 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 by the access and mobility management network element to page the first terminal device.

[0231] Furthermore, the access and mobility management network element pages the first terminal device. For details, please refer to the CN Paging process above.

[0232] Alternatively, the first donor node sends the paging message to the first terminal device. For details, please refer to the RAN Paging process above.

[0233] Optionally, the method further includes:

[0234] S550: 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.

[0235] 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 most recently connected before entering the non-connected state.

[0236] Optionally, the second information may also 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).

[0237] 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 a non-connected state by a third host node, where 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. For details of this step, please refer to the description in S450.

[0238] By sending the second information to the second node, when the mobile relay node moves to the target host node, the second host node and the target host node can interact with each other through the second information to discover the second terminal device in the idle state.

[0239] Optionally, the method further includes:

[0240] S560: The first host node sends third information to the second host node. Correspondingly, the second host node receives the third information from the first host node.

[0241] Among them, the third information indicates whether 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 most recently connected before entering the non-connected state.

[0242] In the case where the second network element is the access and mobility management network element corresponding to the second terminal device, the third information includes identification information of the access and mobility management network element corresponding to the second terminal device.

[0243] Optionally, the method further includes:

[0244] The second host node determines whether it is reachable to the second network element based on the third information. For a specific determination method, refer to the description in S440.

[0245] Optionally, when it is determined that the second network element is unreachable, the method further includes:

[0246] The second host node sends a request message to the first host node, where the request message is used to request paging of the first terminal device, and the request message may carry an identifier of the first terminal device.

[0247] Correspondingly, the first donor node receives the request message from the second donor node, and pages the first terminal device according to the request message. For details, please refer to the CN Paging process above, or refer to the RAN Paging process above.

[0248] Based on the above scheme, the first host node sends indication information to the first network element or the second host node to determine whether the first network element and the second host node are reachable, so that the first network element or the second host node can page the terminal device in a non-connected state managed by the mobile relay node in a timely manner when it is determined that the first network element and the second host node are unreachable.

[0249] In this application, "indication" can be indicated explicitly and / or implicitly. For example, implicit indication can be based on the location and / or resources used for transmission; 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.

[0250] It is understood that the order of steps in each embodiment of the present application is determined by the inherent logic of the solution implementation, and the sequence numbers of the steps in the figures are only examples. Some optional features in each embodiment of the present application may not depend on other features in certain scenarios, and may also be combined with other features in certain scenarios, without limitation.

[0251] The solutions in the various embodiments of the present application can be reasonably combined and used, and the explanations or descriptions of the various terms, similar operations, or steps appearing in the embodiments can be referenced or explained with each other in the various embodiments, without limitation.

[0252] It can also be understood that in the above-mentioned 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 of the first host node, the first network element or the second host node (such as chips, chip systems, processors or circuits).

[0253] It should be understood that the term "and / or" in this application simply describes an association relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. A and B can be singular or plural. Furthermore, the character " / " in this document generally indicates an "or" relationship between the associated objects, but it may also indicate an "and / or" relationship. For specific understanding, please refer to the context.

[0254] In this application, "at least one item" refers to one item or multiple items, "at least two items" and "multiple items" refer to two items or more. "At least one of the following items" or similar expressions refers to any combination of these items, including any combination of single items or multiple items. For example, at least one item of a, b, or c can be represented by: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or multiple. Unless otherwise specified, the term "multiple" in this application means 2 or more.

[0255] The method embodiment of the present application is described above in conjunction with Figures 4 and 5. The device embodiment of the present application is described below. It can be understood that the description of the method embodiment and the description of the device embodiment can correspond to each other. Therefore, for parts not described, reference can be made to the previous method embodiment.

[0256] The above mainly introduces the solution provided by the embodiment of the present application from the perspective of the interaction between various network elements. It can be understood that each network element, such as a transmitting end device or a receiving end device, includes a hardware structure and / or software module corresponding to the execution of each function in order to implement the above functions. Those skilled in the art should be aware that, in combination with the units and algorithm steps of each example described in the embodiments disclosed herein, the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a function is executed in a hardware or computer software driven hardware manner depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0257] In the embodiment of the present application, the functional modules of the transmitting device or the receiving device can be divided according to the above method example. For example, each functional module can be divided according to each function, or two or more functions can be integrated into one processing module. The above integrated modules can be implemented in the form of hardware or in the form of software functional modules. It should be noted that the division of modules in the embodiment of the present application is schematic and is only a logical functional division. There may be other division methods in actual implementation. The following is an example of dividing each functional module according to each function.

[0258] FIG6 is a schematic structural diagram of a communication device 600 provided in an embodiment of the present application.

[0259] The apparatus 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 called a communication interface or a communication unit.

[0260] Optionally, the transceiver unit 610 may include a sending unit and a receiving unit. The sending unit is configured to perform the sending operation in the above method embodiment. The receiving unit is configured to perform the receiving operation in the above method embodiment.

[0261] It should be noted that the communication device 600 may include a sending unit but not a receiving unit. Alternatively, the communication device 600 may include a receiving unit but not a sending unit. The specific implementation depends on whether the above solution executed by the communication device 600 includes a sending action and a receiving action.

[0262] Optionally, the apparatus 600 further includes a processing unit 620. The processing unit 620 may be configured to enable the apparatus to implement the actions of the first host node, the first network element, or the second host node performing processing in the aforementioned various method embodiments.

[0263] Optionally, the device 600 also includes a storage unit, which can be used to store instructions and / or data, and the processing unit 620 can read the instructions and / or data in the storage unit so that the device implements the actions of the first host node, the first network element or the second host node performing processing in the aforementioned method embodiments.

[0264] In one design, the device 600 may be the first host node in the aforementioned embodiment, or may be a component of the first host node (such as a chip, a chip system, a processor, or a circuit). The device 600 may implement steps or processes corresponding to those performed by the first host node in the above method embodiment, wherein the transceiver unit 610 may be used to perform the transceiver-related operations of the first host node in the above method embodiment, and the processing unit 620 may be used to perform the processing-related operations of the first host node in the above method embodiment.

[0265] The device 600 can implement the steps or processes executed by the first host node in the method embodiment according to the embodiment of the present application. The device 600 may include a unit for executing the method executed by the first host node in the embodiment shown in Figure 4 or Figure 5.

[0266] In another design, the apparatus 600 may be the first network element in the aforementioned embodiment, or may be a component of the first network element (such as a chip, a chip system, a processor, or a circuit). The apparatus 600 may implement steps or processes corresponding to those performed by the first network element in the above method embodiment, wherein the transceiver unit 610 may be configured to perform operations related to transceiving of the first network element in the above method embodiment, and the processing unit 620 may be configured to perform operations related to processing of the first network element in the above method embodiment.

[0267] The device 600 can implement the steps or processes executed by the first network element in the method embodiment according to the embodiment of the present application. The device 600 may include a unit for executing the method executed by the first network element in the embodiment shown in Figure 4 or Figure 5.

[0268] In another design, the device 600 may be the second host node in the aforementioned embodiment, or may be a component of the second host node (such as a chip, a chip system, a processor, or a circuit). The device 600 may implement steps or processes corresponding to those performed by the second host node in the above method embodiment, wherein the transceiver unit 610 may be used to perform the transceiver-related operations of the second host node in the above method embodiment, and the processing unit 620 may be used to perform the processing-related operations of the second host node in the above method embodiment.

[0269] The device 600 can implement the steps or processes executed by the second host node in the method embodiment according to the embodiment of the present application. The device 600 may include a unit for executing the method executed by the second host node in the embodiment shown in Figure 4 or Figure 5.

[0270] FIG7 is a schematic diagram of the structure of a communication device 700 provided in an embodiment of the present application. The device 700 includes a processor 710, which 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, to perform the methods in the above method embodiments.

[0271] In some embodiments, the processor 710 is one or more.

[0272] In some embodiments, the memory 720 is one or more.

[0273] In some embodiments, the memory 720 is integrated with the processor 710 or is separately provided.

[0274] In some embodiments, as shown in Figure 7, the apparatus 700 further includes a transceiver 730, which is configured to receive and / or transmit signals. For example, the processor 710 is configured to control the transceiver 730 to receive and / or transmit signals.

[0275] As a solution, the device 700 is used to implement the operations performed by the first host node in the above various method embodiments.

[0276] As another solution, the device 700 is used to implement the operations performed by the first network element in the above various method embodiments.

[0277] As another solution, the device 700 is used to implement the operations performed by the first host node in the above various method embodiments.

[0278] It should be understood that the processor mentioned in the embodiments of the present application may be a central processing unit (CPU), or may be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor, etc.

[0279] It should also be understood that the memory mentioned in the embodiments of the present application may be a volatile memory and / or a non-volatile memory. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM). For example, RAM can be used as an external cache. By way of example and not limitation, RAM includes the following forms: static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM), and direct rambus RAM (DR RAM).

[0280] 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) can be integrated into the processor.

[0281] It should also be noted that the memory described herein is intended to comprise, but not be limited to, these and any other suitable types of memory.

[0282] An embodiment of the present application further provides a computer-readable storage medium storing computer instructions for implementing the methods executed by the first host node, the first network element or the second host node in the above-mentioned method embodiments.

[0283] An embodiment of the present application further provides a computer program product comprising instructions, which, when executed by a computer, implement the methods performed by the first host node, the first network element, or the second host node in the above-mentioned method embodiments.

[0284] An embodiment of the present application further provides a communication system, the communication system including 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.

[0285] The explanation of the relevant contents and beneficial effects of any of the above-mentioned devices can be referred to the corresponding method embodiments provided above, which will not be repeated here.

[0286] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0287] 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 process or function described in the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. 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 computer-readable storage medium. 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 wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) mode. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more available media integrations. The available medium may be a magnetic medium (e.g., a floppy disk, a hard disk, a magnetic tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid state disk (SSD)). For example, the aforementioned available medium includes, but is not limited to, various media that can store program code, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0288] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection 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, characterized in that, 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 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.

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 a first network element, the method includes: Receiving first information from a 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 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.

19. The method according to claim 18, characterized in that, 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 a second host node, the method includes: Receiving first information from a 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 a disconnected state, and 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 a third host node to a 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.

27. A communication device, characterized in that, The communication device includes: A processor and a memory, where the memory is used to store a computer program, and 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, and 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, and 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, Includes: 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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