Communication methods, apparatuses, and systems

Abstract

This application discloses a communication method, apparatus, and system applied in the field of mobile communication. The method includes: a first access network device sending a first message to a second access network device to request the retrieval of context information of a terminal device. The first message includes first information, which includes the PLMN identifier information of the target cell or the CGI of the target cell, or a first PCI and a first ARFCN. The first PCI is the physical cell identifier of the target cell under the first access network device, and the first downlink ARFCN is the downlink ARFCN of the target cell under the first access network device. The second access network device generates a key based on the first information or generates a key based on the PCI and downlink ARFCN of the target cell determined by the first information, and sends a second message to the second access network device. The second message is used to transfer the context information of the terminal device and includes the generated key. This method can avoid failures in the RRC recovery or RRC re-establishment process due to key inconsistency.

Description

Technical Field

[0001] This application relates to the field of mobile communication technology, and in particular to a communication method, apparatus and system. Background Technology

[0002] In Long Term Evolution (LTE) mobile communication systems and the Fifth Generation (5G) New Radio (NR) mobile communication technology, network sharing technology is supported. Network sharing refers to the sharing of wireless networks between different operators, including the sharing of base stations or one or more cells under a base station among multiple operators, providing services to multiple operators. Network sharing enables an operator to quickly deploy its network by leveraging the networks of other operators, saving investment costs.

[0003] However, the inventors of this application have discovered that in network sharing scenarios, there may be situations where Radio Resource Control (RRC) connection re-establishment fails or RRC connection recovery fails. Summary of the Invention

[0004] This application provides a communication method, apparatus, and system. According to the technical solution provided in this application, the key used by the first access network device and the key used by the terminal device can be kept consistent, thereby avoiding failure of the RRC recovery process or RRC re-establishment process due to key inconsistency.

[0005] Firstly, a communication method is provided. It is understood that this method can be executed by a first device, which can be a communication device or a communication device capable of supporting the functions required for the communication device to implement the method, such as a chip system. Exemplarily, the communication device can be a second access network device. The following description assumes that the method is implemented by a second access network device.

[0006] The method includes: a second access network device receiving a first message from a first access network device, wherein the first message is used to request the transfer of context information of a terminal device, the first message including first information, which includes the PLMN identifier information of the target cell to which the terminal device belongs under the first access network device, or the CGI of the target cell under the first access network device, or the first PCI and the first ARFCN, wherein the first PCI is the physical cell identifier of the target cell under the first access network device, and the first downlink ARFCN is the downlink ARFCN of the target cell under the first access network device. The second access network device generates a key based on the first information or generates a key based on the PCI and downlink ARFCN of the target cell determined by the first information, and sends a second message to the second access network, wherein the second message is used to transfer the context information of the terminal device, and the second message includes the generated key. This method ensures that the key used by the first access network device and the key used by the terminal device are consistent, thereby avoiding failures in the RRC recovery process or RRC re-establishment process due to key inconsistency.

[0007] In some possible implementations of the first aspect, the second access network device determines the target cell based on the PLMN identifier information of the target cell to which the terminal device belongs under the first access network device, which is included in the first message, or the CGI of the target cell of the terminal device under the first access network device, obtains the PCI and downlink ARFCN of the target cell, and then generates a key based on the PCI and downlink ARFCN of the target cell.

[0008] In some possible implementations of the first aspect, the second access network device generates a key based on the first PCI and the first downlink ARFCN in the received first message. This method results in low implementation complexity for the second access network device.

[0009] Secondly, a communication method is also provided. It is understood that this method can be executed by a second device, which can be a communication device or a communication device capable of supporting the functions required for the communication device to implement the method, such as a chip system. Exemplarily, the communication device can be a first access network device. The following description assumes that the method is implemented by the first access network device.

[0010] The method includes: a first access network device sending a first message to a second access network device, wherein the first message is used to request the transfer of context information of a terminal device, and the first message includes first information, which includes the PLMN identifier information of the target cell to which the terminal device belongs under the first access network device, or the CGI of the target cell under the first access network device, or the first PCI and the first ARFCN, wherein the first PCI is the physical cell identifier of the target cell under the first access network device, and the first downlink ARFCN is the downlink ARFCN of the target cell under the first access network device. The first access network device receives a second message from the second access network device, wherein the second message is used to transfer the context information of the terminal device, and the second message includes a key, which is generated by the second access network device based on the first information, or generated based on the PCI and downlink ARFCN of the target cell determined by the first information. The first access network device communicates with the terminal device based on the key. This method ensures that the key used by the first access network device and the key used by the terminal device are consistent, thereby avoiding failures in the RRC recovery process or RRC re-establishment process due to key inconsistency.

[0011] Thirdly, a communication method is also provided. It is understood that the method of the first aspect can be executed by a first device, which can be a communication device or a communication device capable of supporting the functions required for the communication device to implement the method, such as a chip system. Exemplarily, the communication device can be a second access network device. The following description assumes that the method is implemented by a second access network device.

[0012] The method includes: a second access network device receiving a first message from a first access network device, wherein the first message is used to request the transfer of context information of the terminal device, and the first message includes a first cell identifier, which is a unique cell identifier of the target cell of the terminal device under the first access network device within the Public Land Mobile Network (PLMN); the second access network device determining multiple candidate target cells with the first cell identifier; the second access network device generating multiple keys corresponding to the multiple candidate target cells, that is, the second access network device generating a corresponding key for each candidate target cell; and the second access network device sending a second message to the first access network device, wherein the second message is used to transfer the context information of the terminal device, and the second message includes multiple keys and cell information of the candidate target cells corresponding to the multiple keys respectively. This method ensures that the keys used by the first access network device and the keys used by the terminal device are consistent, thereby avoiding failures in the RRC recovery or RRC re-establishment process due to key inconsistencies.

[0013] Optionally, when identifying candidate target cells, the second access network device can further limit the candidate target cell to a cell under the first access network device, that is, a cell under the first access network device that has a first cell identifier. If it is not a cell under the first access network device, even if its CellIdentity is the same as the CellIdentity of the received target cell, the second access network device will not consider it a candidate target cell. This can reduce the number of candidate target cells, reduce the computational overhead of generating the key, and reduce the signaling overhead of the second message.

[0014] In some possible implementations of the third aspect, the second access network device generates corresponding keys based on the PCI and downlink ARFCN of each of the multiple candidate target cells.

[0015] In some possible implementations of the third aspect, the cell information of the candidate target cell includes the PLMN identifier information to which the candidate target cell belongs, or the CGI of the candidate target cell, or the PCI and downlink ARFCN of the candidate target cell, so as to identify or distinguish different candidate target cells.

[0016] It should be noted that the third aspect can be used in conjunction with other aspects, such as the first aspect. When the first message includes the first information, the method provided by the first aspect can be followed. When the first message does not include the first information, the method provided by the third aspect can be followed.

[0017] Fourthly, a communication method is also provided. It is understood that this method can be executed by a second device, which can be a communication device or a communication device capable of supporting the functions required for the communication device to implement the method, such as a chip system. Exemplarily, the communication device can be a first access network device. The following description assumes that the method is implemented by the first access network device.

[0018] The method includes: a first access network device sending a first message to a second access network device, wherein the first message is used to request the transfer of context information of the terminal device, and the first message includes a first cell identifier, which is a unique cell identifier of the target cell of the terminal device under the first access network device within the Public Land Mobile Network (PLMN); the first access network device receiving a second message from the second access network device, wherein the second message is used to transfer the context information of the terminal device, and the second message includes multiple keys and cell information of candidate target cells corresponding to the multiple keys, wherein the candidate target cells are cells with the first cell identifier; the first access network device selecting a key corresponding to the target cell based on the cell information of the candidate target cells; and the first access network device communicating with the terminal device based on the selected key. This method ensures that the key used by the first access network device and the key used by the terminal device are consistent, thereby avoiding failures in the RRC recovery or RRC re-establishment process due to key inconsistency.

[0019] Optionally, the candidate target cell is a cell with a first cell identifier under the first access network device.

[0020] In some possible implementations of the fourth aspect, the cell information of the candidate target cell includes the PLMN identifier information to which the candidate target cell belongs, or the CGI of the candidate target cell, or the PCI and downlink ARFCN of the candidate target cell.

[0021] In some possible implementations of the fourth aspect, the first access network device selects a key corresponding to a candidate target cell that has the same PLMN identification information as the target cell; or, the first access network device selects a key corresponding to a candidate target cell that has the same CGI as the target cell; or, the first access network device selects a key corresponding to a candidate target cell that has the same PCI and downlink ARFCN as the target cell.

[0022] Fifthly, a communication method is also provided. It is understood that the method of this fifth aspect can be executed by a first device, which can be a communication device or a communication device capable of supporting the functions required for the communication device to implement the method, such as a chip system. Exemplarily, the communication device can be a second access network device. The following description assumes that the method is implemented by a second access network device.

[0023] The method includes: a second access network device receiving a first message from a first access network device, wherein the first message is used to request the transfer of context information of the terminal device, and the first message includes a first cell identifier, which is a unique cell identifier of the target cell of the terminal device under the first access network device within the Public Land Mobile Network (PLMN); the second access network device determines that there are multiple candidate target cells with the first cell identifier; the second access network device rejects the transfer of context information of the terminal device and sends a third message to the first access network device to indicate that the transfer of context information of the terminal device has failed. This method can restore data transmission of the terminal device more quickly and reduce the interruption time of user data transmission of the terminal device.

[0024] Optionally, the third message includes a reason value, which can be used to indicate that the failure is due to the existence of multiple candidate target cells, the inability to determine the target cell, or the inability to generate a key, etc.

[0025] It should be noted that the fifth aspect can be used in conjunction with other aspects, such as the first aspect. When the first message includes the first information, the method provided by the first aspect can be followed. When the first message does not include the first information, the method provided by the fifth aspect can be followed.

[0026] Sixthly, a communication method is also provided. It is understood that the method of this sixth aspect can be executed by a first device, which can be a communication device or a communication device capable of supporting the functions required for the communication device to implement the method, such as a chip system. Exemplarily, the communication device can be a second access network device. The following description assumes that the method is implemented by a second access network device.

[0027] The method includes: a second access network device receiving a first message from a first access network device, wherein the first message is used to request the transfer of context information of a terminal device, and the first message includes a first cell identifier, which is a unique cell identifier of the target cell of the terminal device under the first access network device within the Public Land Mobile Network (PLMN); the second access network device determines the target cell based on the CellIdentity of the target cell and the PLMN identifier of the terminal device in the second access network device, and generates a key using the PCI and downlink ARFCN of the target cell; the second access network device sends a second message to the first access network device to transfer the context information of the terminal device to the first access network device, and the second message includes the generated key. This method can improve the accuracy of the generated key, thereby reducing the failure rate of the RRC recovery process or RRC re-establishment process due to key inconsistency.

[0028] In some possible implementations of the sixth aspect, the second access network device first identifies candidate target cells based on the CellIdentity of the received target cell. If the second access network device identifies multiple candidate target cells with the same CellIdentity, it can select the candidate target cell that is identical to the PLMN identifier of the terminal device in the second access network device as the target cell, and then generate a key based on the PCI and ARFCN of that target cell. Optionally, if only one candidate target cell is identified, the PCI and ARFCN of that candidate target cell are used directly to generate the key.

[0029] In some possible implementations of the sixth aspect, the second access network device determines the target cell based on the received CellIdentity of the target cell and the PLMN identifier of the terminal device in the second access network device, and generates a key based on the PCI and downlink ARFCN of the determined target cell.

[0030] It should be noted that the sixth aspect can be used in conjunction with other aspects, such as the first aspect. When the first message includes the first information, the method provided by the first aspect can be followed. When the first message does not include the first information, the method provided by the sixth aspect can be followed. For example, when there is no candidate target cell among the multiple candidate target cells that is the same as the PLMN of the terminal device under the second access network device, the method provided by the third or fifth aspect can be followed; when there is a candidate target cell among the multiple candidate target cells that is the same as the PLMN of the terminal device under the second access network device, the method provided by the sixth aspect can be followed.

[0031] The methods in the first to sixth aspects can be applied to both RRC recovery and RRC re-establishment scenarios.

[0032] In some possible implementations of the first, second, third, fourth, and sixth aspects, the first message may be a retrieval of user equipment context request message, and the second message may be a retrieval of user equipment context response message.

[0033] In some possible implementations of the fifth aspect, the first message may be a request message to retrieve the user device context, and the third message may be a failure message to retrieve the user device context.

[0034] In a seventh aspect, a communication device is provided, which has the function of implementing the corresponding operations in the method of the first aspect described above. The function can be implemented by hardware or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above functions. In one possible design, the communication device includes: a receiving unit for receiving a first message from a first access network device, wherein the first information includes PLMN identification information of the target cell to which the terminal device belongs under the first access network device, or the CGI of the target cell of the terminal device under the first access network device, or a first PCI and a first ARFCN, wherein the first PCI is the physical cell identifier of the target cell of the terminal device under the first access network device, and the first downlink ARFCN is the downlink ARFCN of the target cell of the terminal device under the first access network device; a processing unit for generating a key based on the first information or generating a key based on the PCI and downlink ARFCN of the target cell determined by the first information; and a sending unit for sending a second message to a second access network, wherein the second message is used to transfer the context information of the terminal device, and the second message includes the generated key. These modules can perform the corresponding functions in the method examples of the first aspect described above, as detailed in the method examples, and will not be repeated here.

[0035] Eighthly, a communication device is provided, which has the function of implementing the corresponding operations in the method of the third aspect described above. The function can be implemented by hardware or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above functions. In one possible design, the communication device includes: a receiving unit for receiving a first message from a first access network device, wherein the first message includes a first cell identifier, which is a unique cell identifier of a target cell of a terminal device under the first access network device within the Public Land Mobile Network (PLMN); a processing unit for determining multiple candidate target cells with the first cell identifier and generating multiple keys corresponding to the multiple candidate target cells; and a sending unit for sending a second message to a second access network, wherein the second message is used to transfer the context information of the terminal device, and the second message includes multiple keys and cell information of the candidate target cells corresponding to the multiple keys. These modules can perform the corresponding functions in the method examples of the third aspect described above, as detailed in the method examples, and will not be repeated here.

[0036] Ninthly, a communication device is provided, which has the function of implementing the corresponding operations in the method of the fifth aspect above. The function can be implemented by hardware or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above functions. In one possible design, the communication device includes: a receiving unit for receiving a first message from a first access network device, wherein the first message includes a first cell identifier, which is a unique cell identifier of a target cell of the terminal device under the first access network device within the Public Land Mobile Network (PLMN); a processing unit for determining that when multiple candidate target cells with the first cell identifier exist, the transfer of the terminal device's context information should be rejected; and a sending unit for sending a third message to a second access network, wherein the third message indicates that the transfer of the terminal device's context information has failed. These modules can perform the corresponding functions in the method examples of the fifth aspect above, as detailed in the method examples, and will not be repeated here.

[0037] In a tenth aspect, a communication device is provided, which has the function of implementing the corresponding operations in the method of the sixth aspect described above. The function can be implemented by hardware or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above functions. In one possible design, the communication device includes: a receiving unit for receiving a first message from a first access network device, wherein the first message includes a first cell identifier, which is a unique cell identifier of a target cell of a terminal device under the first access network device within the Public Land Mobile Network (PLMN) range; a processing unit for determining, when multiple candidate target cells with the first cell identifier exist, to select the cell whose PCI and downlink ARFCN are the same as the PLMN identifier of the terminal device in the second access network device from among the multiple candidate target cells to generate a key; and a sending unit for sending a second message to the second access network, wherein the second message is used to transfer the context information of the terminal device, and the second message includes the generated key. These modules can perform the corresponding functions in the method examples of the sixth aspect described above, as detailed in the method examples, and will not be repeated here.

[0038] Eleventhly, a communication device is provided, which has the function of implementing the corresponding operation in the method of the second aspect described above. This function can be implemented by hardware or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above-described function. In one possible design, the communication device includes: a sending unit, configured to send a first message to a second access network device, wherein the first message is used to request the transfer of context information of a terminal device, the first message including first information, which includes PLMN identifier information of the target cell to which the terminal device belongs under the first access network device, or CGI of the target cell of the terminal device under the first access network device, or first PCI and first ARFCN, wherein the first PCI is the physical cell identifier of the target cell of the terminal device under the first access network device, and the first downlink ARFCN is the downlink ARFCN of the target cell of the terminal device under the first access network device; a receiving unit, configured to receive a second message from the second access network device, wherein the second message is used to transfer the context information of the terminal device, the second message including a key, which is generated by the second access network device based on the first information, or generated based on the PCI and downlink ARFCN of the target cell determined by the first information; and a processing unit, configured to communicate with the terminal device based on the key. These modules can perform the corresponding functions in the method examples in the second aspect above. Please refer to the detailed description in the method examples for details, which will not be repeated here.

[0039] In a twelfth aspect, a communication device is provided, which has the function of implementing the corresponding operations in the method of the fourth aspect described above. This function can be implemented by hardware or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above functions. In one possible design, the communication device includes: a sending unit, configured to send a first message to a second access network device, wherein the first message is used to request the transfer of context information of a terminal device, the first message including a first cell identifier, the first cell identifier being a unique cell identifier of a target cell of the terminal device under the first access network device within the Public Land Mobile Network (PLMN); a receiving unit, configured to receive a second message from the second access network device, wherein the second message is used to transfer the context information of the terminal device, the second message including multiple keys and cell information of candidate target cells corresponding to the multiple keys, the candidate target cells being cells with the first cell identifier; and a processing unit, configured to select a key corresponding to the target cell based on the cell information of the candidate target cells, and to communicate with the terminal device based on the selected key. These modules can perform the corresponding functions in the method examples of the fourth aspect described above, as detailed in the method examples, and will not be repeated here.

[0040] In a thirteenth aspect, a communication device is provided. This communication device can be a communication device implementing the methods of any one of the first to sixth aspects described above, or a chip disposed in a communication device implementing the methods of any one of the first to sixth aspects described above. The communication device includes a communication interface and a processor, and optionally, a memory. The memory is used to store computer programs, instructions, or data. The processor is coupled to the memory and the communication interface. When the processor reads the computer program, instructions, or data, it causes the communication device to execute the methods executed by the first access network device or the second access network device in each aspect.

[0041] It should be understood that the communication interface can be a transceiver in a communication device, such as through an antenna, feeder, and codec in the communication device. Alternatively, if the communication device is a chip located in an access network device, the communication interface can be the chip's input / output interface, such as input / output pins. This transceiver is used for communication between the communication device and other devices.

[0042] In a fourteenth aspect, embodiments of this application provide a chip system including a processor for implementing the communication methods of any one of the first to sixth aspects. In one possible design, the chip system also includes a memory for storing program instructions and / or data. The chip system may be composed of chips or may include chips and other discrete devices.

[0043] In a fifteenth aspect, embodiments of this application provide a communication system, which includes a communication device for implementing the method of the first aspect and a communication device for implementing the method of the second aspect, or includes a communication device for implementing the method of the third aspect and a communication device for implementing the method of the fourth aspect, or includes a communication device for implementing the method of the fifth aspect and a first access network device, or includes a communication device for implementing the method of the sixth aspect and a first access network device.

[0044] In a sixteenth aspect, a computer program product is provided, comprising: computer program code, which, when executed, causes the methods executed by a first access network device in the above aspects to be performed, or causes the methods executed by a second access network device in the above aspects to be performed.

[0045] In a seventeenth aspect, this application provides a computer-readable storage medium storing a computer program that, when run, implements the methods executed by a first access network device in the above aspects; or implements the methods executed by a second access network device in the above aspects. Attached Figure Description

[0046] Figure 1This is a schematic diagram of the architecture of a communication system used in an embodiment of this application;

[0047] Figure 2 A flowchart illustrating an example of a communication method provided in an embodiment of this application;

[0048] Figure 3 A flowchart illustrating another example of the communication method provided in the embodiments of this application;

[0049] Figure 4 A flowchart illustrating another example of the communication method provided in the embodiments of this application;

[0050] Figure 5 A flowchart illustrating another example of the communication method provided in the embodiments of this application;

[0051] Figure 6 A flowchart illustrating another example of the communication method provided in the embodiments of this application;

[0052] Figure 7 A flowchart illustrating another example of the communication method provided in the embodiments of this application;

[0053] Figure 8 A schematic diagram of the structure of a communication device provided in an embodiment of this application;

[0054] Figure 9 This is another schematic diagram of the communication device provided in the embodiments of this application;

[0055] Figure 10 This is another schematic diagram of the communication device provided in the embodiments of this application; Detailed Implementation

[0056] The terms "first," "second," and "third," etc., used in the specification, claims, and drawings of this application are used to distinguish different objects, not to limit a specific order. In the embodiments of this application, words such as "exemplary" or "for example" are used to indicate that they are examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design solutions. Specifically, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0057] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0058] The technical solutions of the embodiments of this application described below can be applied to, for example... Figure 1 The network architecture shown is as follows, in which, Figure 1 This is merely one example of a communication system, which may include multiple terminal devices and multiple network devices. Figure 1 Taking an example that includes two terminal devices and two network devices. Of course... Figure 1 The number of terminal devices mentioned is just an example; it could be fewer or more. Any network device can provide services to terminal devices within its coverage area.

[0059] The terminal device is a device with wireless transceiver capabilities, which can be a fixed device, a mobile device, a handheld device, a wearable device, an in-vehicle device, or a device built into the above-mentioned devices (e.g., a communication module or chip system). The terminal device is used to connect people, objects, machines, etc., and can be widely used in various scenarios. It may also be referred to as user equipment (UE), access terminal, user unit, user station, mobile station, mobile station, remote station, remote terminal, mobile device, user terminal, terminal, wireless communication device, user agent, or user device. In the embodiments of this application, the terminal device can be a mobile phone, tablet computer, computer with wireless transceiver capabilities, virtual reality (VR) terminal device, augmented reality (AR) terminal device, wireless terminal in industrial control, wireless terminal in Internet of Things (IoT) systems, wireless terminal in self-driving, wireless terminal in remote medical care, wireless terminal in smart grid, wireless terminal in transportation safety, or wireless terminal in smart city applications. Wireless terminals in cities, smart homes, cellular phones, cordless phones, session initiation protocol (SIP) phones, wireless local loop (WLL) stations, personal digital assistants (PDAs), handheld devices with wireless communication capabilities, computing devices or other processing devices connected to a wireless modem, in-vehicle devices, in-vehicle communication devices, in-vehicle communication processing chips, wearable devices, terminal devices in 5G networks, or terminal devices in future evolved public land mobile networks (PLMNs), etc. It should be understood that this application does not limit the specific form of the terminal device.

[0060] Network equipment can be access network equipment, also known as radio access network (RAN) equipment. It refers to equipment in the access network that communicates with wireless terminals through one or more sectors on the air interface. It can also be considered a device that provides wireless communication functions for terminal devices. Access network equipment includes, but is not limited to: next-generation node B (gNB), evolved node B (eNB), baseband unit (BBU), transmitting and receiving point (TRP), transmitting point (TP) in 5G, base stations in future mobile communication systems, or access points in WiFi systems. Access network equipment can also be radio controllers, centralized units (CU), and / or distributed units (DU) in cloud radio access network (CRAN) scenarios, or network equipment can be relay stations, vehicle-mounted equipment, and network equipment in future evolved PLMN networks.

[0061] CUs and DUs can be physically separate or deployed together. Multiple DUs can share a single CU. A single DU can also connect to multiple CUs. CUs and DUs can be connected via interfaces, such as F1 interfaces. CUs and DUs can be partitioned according to the protocol layers of the wireless network. For example, one possible partition is: the CU performs functions of the Radio Resource Control (RRC), Service Data Adaptation Protocol (SDAP), and Packet Data Convergence Protocol (PDCP) layers, while the DU performs functions of the Radio Link Control (RLC), Media Access Control (MAC), and physical layers. This partitioning of CU and DU processing functions according to protocol layers is just one example; other partitioning methods are also possible. For example, CUs or DUs can be partitioned to handle functions across more protocol layers. Alternatively, CUs or DUs can be partitioned to handle partial protocol layer processing functions. In one design, some functions of the RLC layer and the protocol layer functions above the RLC layer are located in the CU, while the remaining functions of the RLC layer and the protocol layer functions below the RLC layer are located in the DU. In another design, the functions of the CU or DU can be divided according to service type or other system requirements. For example, based on latency, functions that need to meet latency requirements are located in the DU, while functions that do not need to meet this latency requirement are located in the CU. The network architecture shown in the diagram can be applied to 5G communication systems, and it can also share one or more components or resources with LTE systems. In another design, the CU can also have one or more core network functions. One or more CUs can be centrally located or separately located. For example, the CU can be located on the network side for convenient centralized management. The DU can have multiple radio frequency functions, or the radio frequency functions can be located remotely.

[0062] The functionality of a CU can be implemented by a single entity or by different entities. For example, the functionality of the CU can be further divided, such as separating the control plane (CP) and the user plane (UP), i.e., the CU control plane (CU-CP) and the CU user plane (CU-UP). For example, the CU-CP and CU-UP can be implemented by different functional entities, and the CU-CP and CU-UP can be coupled with the DU to jointly complete the functions of the access network device.

[0063] The terminal device can communicate with access network devices using different technologies. For example, the terminal device can communicate with access network devices supporting long-term evolution (LTE), or with access network devices supporting 5G, or simultaneously with both LTE-enabled and 5G-enabled access network devices. This application's embodiments are not limited to these specific examples.

[0064] To facilitate understanding of this application, the relevant concepts involved in the embodiments of this application are now described.

[0065] A cell can have multiple cell identifiers corresponding to different cell identifier types, each used in different scopes. For example, at the physical layer, there is the Physical Cell Identity (PCI), generally used in the radio interface. Within a Public Land Mobile Network (PLMN), the identifier that uniquely identifies a cell is called the Cell Identity, typically 28 bits. The identifier that uniquely identifies a cell globally is called the Cell Global Identity (CGI) or Global Cell Identity (GCI). For ease of description, this application will consistently use CGI. In one implementation, the CGI consists of a PLMN ID and a Cell Identity.

[0066] In a network sharing scenario, a cell (taking cell A as an example) can be shared by multiple operators. For each operator, or for each PLMN ID, cell A corresponds to a unique CellIdentity. It's understandable that the CellIdentity of the same cell can be the same or different under different PLMN IDs. Therefore, the CellIdentity of cell A under the aforementioned multiple operators can also be the same or different. However, the PCI and downlink absolute radio frequency channel number (ARFCN) of cell A are the same for each PLMN ID. That is, in a network sharing scenario, the PCI and downlink ARFCN of a cell remain unchanged under different PLMN IDs. For a terminal device accessing a shared cell, generally, there is only one serving PLMN; this application embodiment does not limit this. Table 1 shows an example of a configured cell identifier in a network sharing scenario.

[0067] Table 1

[0068]

[0069] Figure 2 An example of an RRC connection recovery process is given.

[0070] S210. The terminal device sends an RRC Resume Request message to the first access network device.

[0071] When a terminal device in the RRC inactive state needs to enter the connected state, it sends an RRC recovery request to the first access network device through its current serving cell. The first access network device here is the terminal device's current serving base station, or target base station; the current serving cell can also be called the target cell for the RRC connection recovery process. The terminal device generates a new key based on the downlink ARFCN and PCI of the current serving cell. It should be noted that the terminal device obtains the downlink ARFCN and PCI of the current serving cell during synchronization; the specific acquisition method can be found in existing technologies and will not be elaborated here.

[0072] S220. The first access network device sends a RETRIEVE UECONTEXT REQUEST message to the second access network device, which carries the cell identifier of the target cell.

[0073] The cell identifier is a unique CellIdentity within a PLMN. The target cell here is the currently serving cell in step S210.

[0074] Upon receiving the RRC recovery request message from the terminal device, the first access network device locates the source base station of the terminal device, which is the base station storing the context of the terminal device, based on the information carried in the RRC recovery request message. Specific methods can be found in existing technologies and will not be elaborated here. It is understood that this source base station can also be called an anchor base station. In this embodiment, such an access network device as the source base station is referred to as the second access network device. Then, the first access network device sends a context retrieval request message to the second access network device.

[0075] S230: The second access network device obtains the downlink ARFCN and PCI of the target cell based on CellIdentity, and generates a key based on the downlink ARFCN and PCI of the target cell.

[0076] When two access network devices establish an interface between base stations (such as an X2 interface or an Xn interface), they exchange cell information for each cell under their respective access network devices. This cell information includes at least the cell's PLMN ID, CellIdentity, PCI, and downlink ARFCN. Each access network device stores the cell information for each cell under the other access network device. This cell information can also be updated subsequently through the inter-base station update process. In addition to storing the cell information for each cell under the first access network device, the second access network device also stores the cell information for each cell under at least the other access network devices that have established an inter-base station interface with the second access network device. It should be noted that the stored information also includes the association between the cell and the access network device, that is, information about which access network device a cell belongs to. After obtaining the context of the terminal device, the second access network device further uniquely determines a target cell, along with its downlink ARFCN and PCI, based on the target cell's CellIdentity and the cell information for each cell under the first access network device stored by the second access network device. The second access network device then uses the target cell's downlink ARFCN and PCI as parameters to generate a key. It should be noted that the process of generating keys based on ARFCN and PCI can refer to existing technologies, and this application embodiment will not elaborate on or limit it.

[0077] S240, the second access network device sends a UECONTEXT RESPONSE message to the first access network device.

[0078] In addition to carrying the context information of the terminal device, the message also carries the key generated in step S230. The first access network device subsequently uses this key to communicate with the terminal device.

[0079] S250. The first access network device sends an RRC recovery message (RRC Resume) to the terminal device.

[0080] The second access network device generates a key using the downlink ARFCN and PCI of the target cell as parameters and sends the generated key to the first access network device. The terminal device also generates a key using the same parameters, so that the terminal device and the first access network device communicate using the same key. It should be noted that the key generated by the terminal device and the key generated by the second access network device must be consistent; otherwise, the terminal device cannot communicate with the first access network device. However, the inventors of this application have discovered that in a network-sharing scenario, there may be multiple cells with the same CellIdentity but different PLMNIDs under the first access network device. That is, in the cell information of the first access network device stored by the second access network device, there are multiple cells with the same CellIdentity. If the target cell is one of these multiple cells, the second access network device cannot uniquely identify a target cell based on the CellIdentity in step S230, and therefore cannot obtain the downlink ARFCN and PCI of the target cell, or obtains an incorrect downlink ARFCN and PCI, further generating an incorrect key, thus causing subsequent RRC recovery failure. Taking Table 1 as an example, if cell1 and cell2 are cells under the first access network device, and the target cell is cell2, then the CellIdentity sent by the first access network device to the second access network device is 2. Since the CellIdentity of PLMN 2 corresponding to cell1 is also 2, the second access network device cannot determine whether the target cell is cell1 or cell2 based on the CellIdentity (2) information. If the second access network device mistakenly identifies the target cell as cell1, it uses PCI (10) to generate a key and sends the key to the first access network device. The first access network device uses the key generated by PCI (10), while the terminal device uses PCI (20) to generate a key. As a result, the keys used by the first access network device and the terminal device are inconsistent, leading to the failure of subsequent RRC recovery.

[0081] It should be noted that in the re-establishment scenario, that is, if the “RRC recovery request message” in step S210 is replaced with the “RRC re-establishment request message” and the “RRC recovery message” in step S250 is replaced with the “RRC re-establishment message”, the key inconsistency problem mentioned above still exists, which will lead to the failure of RRC re-establishment.

[0082] Therefore, the technical solutions provided in the embodiments of this application are presented. The technical solutions provided in the embodiments of this application are described below with reference to the accompanying drawings.

[0083] One embodiment of this application provides a communication method; please refer to [link / reference]. Figure 3 Here is a flowchart of the method. In the following description, this method will be applied to... Figure 1 The illustrated communication system serves as an example. Furthermore, this method can be executed by two communication devices, such as a first access network device and a second access network device. The first and second access network devices can be base stations or communication devices capable of supporting the functions required for the base station to implement this method.

[0084] For ease of explanation, in the following description, the first access network device can be the target access network device or the current serving access network device of the terminal device during the RRC recovery process or the RRC re-establishment process, and the second access network device can be the source access network device or the anchor access network device of the terminal device during the RRC recovery process or the RRC re-establishment process.

[0085] For example, in the RRC recovery scenario, the terminal device enters the RRC deactivation state from the RRC connected state on the second access network device. As the terminal device moves, it enters the coverage area of ​​the first access network device. The terminal device needs to enter the RRC connected state, for example, if it needs to send data. In this case, the terminal device initiates the RRC recovery process on the first access network device. In the RRC re-establishment scenario, if the terminal device experiences a wireless link failure or integrity check failure on the second access network device, the terminal device selects the first access network device to initiate the RRC re-establishment process.

[0086] S310, the first access network device sends a first message to the second access network device to request the retrieval of the context information of the terminal device.

[0087] Accordingly, the second access network device receives the first message. The first message includes first information, which includes the PLMN identifier information of the target cell or the CGI of the target cell.

[0088] In the RRC recovery scenario, the terminal device camps on the target cell, which is a cell under the first access network device. The terminal device sends an RRC recovery request message to the first access network device on the target cell. After receiving the RRC recovery request message, the first access network device identifies that the context information of the terminal device is stored in the second access network device, or in other words, it identifies that the anchor access network device of the terminal device is the second access network device, and then executes step S310.

[0089] In the RRC re-establishment scenario, if the terminal device encounters a problem such as radio link failure or integrity check failure in the second access network device, the terminal device performs a cell selection process to select a target cell under the first access network device. On the target cell, it sends an RRC re-establishment request message to the first access network device. After receiving the RRC re-establishment request message, the first access network device identifies the context information of the terminal device and stores it in the second access network device, or in other words, it identifies the source access network device as the second access network device, and then executes step S310.

[0090] In one possible implementation, the first information includes the PLMN identification information of the target cell. In a network-sharing scenario, there may be multiple cells with this CellIdentity, but these cells each have their own distinct PLMN identifier. The target cell's CellIdentity included in the first message, combined with the target cell's PLMN identification information, can uniquely identify the target cell. The PLMN identification information is used to identify a PLMN network and may include a mobile network code; optionally, it may also include a mobile country code.

[0091] In another possible implementation, the first information includes the CGI of the target cell. The CGI of the target cell can uniquely identify the target cell. Optionally, considering backward compatibility, the CellIdentity included in the first message can be considered an existing information element. In this implementation, a new complete CGI information element is added to the first message. The CellIdentity and CGI in the first message are two independent information elements, although the CGI information element also includes another CellIdentity with the same value.

[0092] The first message could be a RETRIEVE UE CONTEXTREQUEST message between base stations.

[0093] S320: The second access network device determines the target cell based on the first information, and then generates a key based on the target cell's PCI and downlink ARFCN.

[0094] If, in step S310, the first information includes the PLMN identifier information of the target cell, then the second access network device uniquely determines the target cell based on the PLMN identifier information of the target cell, the CellIdentity of the target cell included in the first message, and the cell information of each cell under the first access network device stored by the second access network device, and obtains the PCI and downlink ARFCN of the target cell, and generates a key based on the PCI and downlink ARFCN of the target cell. Taking Table 1 as an example, if the target cell is cell 2, then the first information includes the PLMN identifier information of cell 2, i.e., PLMN 1, and the first message also includes CellIdentity (2). Then, based on the PLMN ID (PLMN 1) and CellIdentity (2), the second access network device determines that the target cell is cell 2 and not cell 1, further obtains the PCI (20) and downlink ARFCN (200) of cell 2, and then generates a key accordingly.

[0095] If the first information in step S310 includes the CGI of the target cell, the second access network device can uniquely determine the target cell based on the CGI of the target cell and the cell information of each cell under the first access network device stored by the second access network device, and obtain the PCI and downlink ARFCN of the target cell, and generate a key based on the PCI and downlink ARFCN of the target cell. Taking Table 1 as an example, if the target cell is cell 2, the first information includes the CGI of cell 2, namely PLMN ID (PLMN1) and CellIdentity (2). The second access network device determines that the target cell is cell 2 and not cell 1 based on the CGI, and further obtains the PCI (20) and downlink ARFCN (200) of cell 2, and then generates a key accordingly.

[0096] It should be noted that the second access network device determines the target cell based on the first information, and then generates a key based on the target cell's PCI and downlink ARFCN. Alternatively, it can be considered that the second access network device generates a key based on the first information.

[0097] In this step, since the second access network device can uniquely identify the target cell based on the first information, it ensures that the key generated by the second access network device and the key generated by the terminal device are consistent. Subsequently, the second access network device sends the generated key to the first access network device, and the first access network device uses the key to communicate with the terminal device, thereby ensuring that the key used by the first access network device and the key used by the terminal device are consistent, thus avoiding failure of the RRC recovery process or RRC re-establishment process due to key inconsistency.

[0098] S330, the second access network device sends a second message to the first access network device to transfer the context information of the terminal device to the first access network device.

[0099] Accordingly, the first access network device receives the second message. The second message includes the key generated in step S320.

[0100] The second message can be a RETRIEVE UE CONTEXTRESPONSE message between base stations.

[0101] Another embodiment of this application provides a communication method; please refer to [link to relevant documentation]. Figure 4 Here is a flowchart of the method. In the following description, this method will be applied to... Figure 1 The illustrated communication system serves as an example. Furthermore, this method can be executed by two communication devices, such as a first access network device and a second access network device. The first and second access network devices can be base stations or communication devices capable of supporting the functions required for the base station to implement this method.

[0102] This embodiment can be applied to RRC recovery or RRC re-establishment scenarios. For details, please refer to [link / reference needed]. Figure 3 The corresponding descriptions of the embodiments shown will not be repeated in this embodiment.

[0103] S410, the first access network device sends a first message to the second access network device to request the retrieval of the context information of the terminal device.

[0104] Accordingly, the second access network device receives the first message. The first message includes first information. The first information includes a first PCI and a first downlink ARFCN. The first PCI is the physical cell identifier of the target cell of the terminal device under the first access network device, and the first downlink ARFCN is the downlink ARFCN of the target cell of the terminal device under the first access network device.

[0105] It is understandable that S410 is similar to the implementation of S310 described above, except that the content of the first piece of information is different. Further information on the implementation of S410 can be found by referring to [link / reference needed]. Figure 3 The corresponding descriptions in the illustrated embodiments will not be repeated in this embodiment.

[0106] S420, the second access network device generates a key based on the target cell's PCI and downlink ARFCN.

[0107] In one possible implementation, the second access network device does not need to uniquely determine the target cell, but can directly use the received target cell's PCI and downlink ARFCN as parameters to generate the key. This method reduces the implementation complexity of the second access network. Taking Table 1 as an example, if the target cell is cell 2, the first information includes cell 2's PCI (20) and downlink ARFCN (200), and then the key is directly generated based on the received PCI (20) and downlink ARFCN (200).

[0108] In another possible implementation, the second access network device can first uniquely determine the target cell based on the CellIdentity, PCI, and downlink ARFCN of the target cell included in the first message, and then use the determined target cell's PCI and downlink ARFCN as parameters to generate a key. Taking Table 1 as an example, if the target cell is cell 2, the first information includes the PCI (20) and downlink ARFCN (200) of cell 2. The first message also includes CellIdentity (2). Based on CellIdentity (2), PCI (20), and downlink ARFCN (200), it is determined that the target cell is cell 2 and not cell 1. The PCI (20) and downlink ARFCN (200) of cell 2 are obtained, and then a key is generated accordingly.

[0109] In this step, since the second access network device can obtain the correct PCI and downlink ARFCN of the target cell, it ensures that the key generated by the second access network device is consistent with the key generated by the terminal device. Subsequently, the second access network device sends the generated key to the first access network device, and the first access network device uses the key to communicate with the terminal device, thereby ensuring that the key used by the first access network device is consistent with the key used by the terminal device, thus avoiding failure of the RRC recovery process or RRC re-establishment process due to key inconsistency.

[0110] S430, the second access network device sends a second message to the first access network device to transfer the context information of the terminal device to the first access network device.

[0111] Accordingly, the first access network device receives the second message. The second message includes the key generated in step S420.

[0112] It is understandable that S430 is implemented similarly to S330 described above; further details can be found by referring to relevant resources. Figure 3 The corresponding descriptions in the illustrated embodiments will not be repeated in this embodiment.

[0113] Another embodiment of this application provides a communication method; please refer to [link to relevant documentation]. Figure 5Here is a flowchart of the method. In the following description, this method will be applied to... Figure 1 The illustrated communication system serves as an example. Furthermore, this method can be executed by two communication devices, such as a first access network device and a second access network device. The first and second access network devices can be base stations or communication devices capable of supporting the functions required for the base station to implement this method.

[0114] This embodiment can be applied to RRC recovery or RRC re-establishment scenarios. For details, please refer to [link / reference needed]. Figure 3 The corresponding descriptions of the embodiments shown will not be repeated in this embodiment.

[0115] S510, the first access network device sends a first message to the second access network device to request the retrieval of the context information of the terminal device.

[0116] Accordingly, the second access network device receives the first message. This first message includes a first cell identifier, which is a unique cell identifier of the target cell within the PLMN range for the terminal device under the first access network device; that is, the CellIdentity of the target cell. The first message may be a RETRIEVEUE CONTEXT REQUEST message between base stations.

[0117] It is understandable that step S510 can be executed during RRC recovery or RRC rebuild scenarios; see details below. Figure 3 The corresponding descriptions in the illustrated embodiments will not be repeated in this embodiment.

[0118] S520: The second access network device determines at least one candidate target cell based on the CellIdentity of the target cell, and generates a corresponding key based on the PCI and downlink ARFCN of each candidate target cell.

[0119] In a network sharing scenario, the second access network device may identify one or more candidate target cells based on the received target cell's CellIdentity. This means that the CellIdentity of these one or more candidate target cells is the same as the CellIdentity of the received target cell. When there are multiple candidate target cells, each candidate target cell has a different PLMN identifier.

[0120] Optionally, when identifying candidate target cells, it can be limited to cells under the first access network device, that is, cells under the first access network device that have a first cell identifier. If a cell is not under the first access network device, even if its CellIdentity is the same as the CellIdentity of the received target cell, the second access network device will not consider it a candidate target cell. This reduces the number of candidate target cells, lowers the computational overhead of generating the key, and reduces the signaling overhead of sending the second message in the subsequent step S530. Of course, it is also possible not to limit the candidate cells to cells under the first access network device, which simplifies the process.

[0121] The second access network device generates a corresponding key based on the PCI and downlink ARFCN of each candidate target cell. Taking Table 1 as an example, if the target cell is cell 2, the first message includes the CellIdentity (2) of the target cell. Based on the CellIdentity of the target cell, the second access network device identifies two candidate target cells under the first access network device with CellIdentity (2), namely cell 1 and cell 2. Then, the second access network device uses the PCI (10) of cell 1 and the downlink ARFCN (100) to generate a key 1 corresponding to cell 1, and uses the PCI (20) of cell 2 and the downlink ARFCN (200) to generate a key 2 corresponding to cell 2.

[0122] S530, the second access network device sends a second message to the first access network device to transfer the context information of the terminal device to the first access network device.

[0123] Accordingly, the first access network device receives the second message. The second message includes at least one key generated in step S520 and cell information of the candidate target cell corresponding to each key.

[0124] Each key corresponds to the cell information of a candidate target cell. This cell information is used to identify or distinguish different candidate target cells, or it can be combined with the CellIdentity in the first message to identify or distinguish different candidate target cells. The cell information of a candidate target cell may include the PLMN identifier information, the PCI and downlink ARFCN, or the CGI. Taking the PLMN identifier information as an example, in the S520 example, the second message would include: {key 1, PLMN 2} corresponding to cell 1, and {key 2, PLMN 1} corresponding to cell 2. The combination of PLMN 2 and the CellIdentity in the first message can be used to identify cell 1, and the combination of PLMN 1 and the CellIdentity in the first message can be used to identify cell 2.

[0125] Given that the second message already contains a first information element corresponding to a key, this first information element can include the key information of the first candidate cell. Therefore, the second message will also contain a second information element indicating the cell information of the first candidate target cell. Furthermore, the second message may include a list of all other candidate target cells besides the first candidate target cell. Each element in the list corresponds to a key and the cell information of the candidate target cell corresponding to that key. It is understood that this list can include one or more elements. The first candidate target cell can be any candidate target cell, or it can be a candidate target cell that is identical to the PLMN identifier of the terminal device in the second access network device, or it can be a candidate target cell that the second access network device considers most likely to be the target cell.

[0126] In another possible implementation, the second message may include a list of all candidate target cells, where each element in the list corresponds to a key and the cell information of the candidate target cell corresponding to that key.

[0127] The second message can be a UE context retrieval response message between base stations (i.e., RETRIEVE UE CONTEXTRESPONSE).

[0128] S540. The first access network device selects a key corresponding to the target cell based on the cell information of the candidate target cell, and communicates with the terminal device based on the key.

[0129] The first access network device can select the key corresponding to the cell information of the candidate target cell that is consistent with the cell information of the target cell, based on the cell information of the target cell and the cell information of the received candidate target cells.

[0130] For example, in the S530 example, the second access network device selects the key corresponding to the PLMN identifier of cell 2 (i.e., PLMN 1), i.e. key 2, as the key used to communicate with the terminal device.

[0131] In this embodiment, the first access network device selects a key corresponding to the target cell based on the cell information of the candidate target cell, thereby ensuring that the key used by the first access network device and the key used by the terminal device are consistent, thus avoiding failure of the RRC recovery process or RRC re-establishment process due to key inconsistency.

[0132] Another embodiment of this application provides a communication method; please refer to [link to relevant documentation]. Figure 6 Here is a flowchart of the method. In the following description, this method will be applied to... Figure 1 The illustrated communication system serves as an example. Furthermore, this method can be executed by two communication devices, such as a first access network device and a second access network device. The first and second access network devices can be base stations or communication devices capable of supporting the functions required for the base station to implement this method.

[0133] This embodiment can be applied to RRC recovery or RRC re-establishment scenarios. For details, please refer to [link / reference needed]. Figure 3 The corresponding descriptions of the embodiments shown will not be repeated in this embodiment.

[0134] S610, the first access network device sends a first message to the second access network device to request the retrieval of the context information of the terminal device.

[0135] Accordingly, the second access network device receives the first message. This first message includes a first cell identifier, which is a unique cell identifier of the target cell within the PLMN range for the terminal device under the first access network device; that is, the CellIdentity of the target cell. The first message may be a RETRIEVEUE CONTEXT REQUEST message between base stations.

[0136] It is understandable that step S610 can be executed during RRC recovery or RRC rebuild scenarios; see details below. Figure 3 The corresponding descriptions in the illustrated embodiments will not be repeated in this embodiment.

[0137] S620: The second access network device determines that there are multiple candidate target cells based on the CellIdentity of the target cell and refuses to transfer the context information of the terminal device.

[0138] In a network sharing scenario, if the second access network device determines that there are multiple candidate target cells with the same CellIdentity, but cannot determine which of these candidate cells is the actual target cell, in this embodiment, the second access network device can refuse to transfer the terminal device's context. Compared to selecting an incorrect target cell to generate a key, which may lead to failure due to key inconsistency, refusing to transfer the terminal device's context allows for faster recovery of data transmission, reducing latency and signaling overhead.

[0139] Optionally, the candidate target cell can be limited to a cell under the first access network device. If it is not a cell under the first access network device, even if its CellIdentity is the same as the CellIdentity of the received target cell, the second access network device will not consider it a candidate target cell. The advantage of doing so is that it may reduce the number of candidate target cells. When it is reduced to one, in this embodiment, it can avoid the failure of transferring the context information of the terminal device, and further avoid the failure of the RRC recovery process or re-establishment process.

[0140] Taking Table 1 as an example, if the target cell is cell 2, the first message includes the CellIdentity (2) of the target cell. Based on the CellIdentity of the target cell, the second access network device identifies two candidate target cells under the first access network device with CellIdentity (2), namely cell 1 and cell 2. The second access network device cannot determine whether the target cell is cell 1 or cell 2, and the second access network device refuses to transfer the context information of the terminal device.

[0141] S630, the second access network device sends a third message to the first access network device to indicate that the context information of the transfer terminal device has failed.

[0142] Accordingly, the first access network device receives the third message.

[0143] Optionally, the third message includes a reason value, which can be used to indicate that the failure is due to the existence of multiple candidate target cells, the inability to determine the target cell, or the inability to generate a key, etc.

[0144] The third message could be a RETRIEVE UE CONTEXTFAILURE message between base stations.

[0145] After receiving the third message, the first access network device can send an RRC re-establishment rejection message to the terminal device if it is an RRC re-establishment scenario, or an RRC recovery rejection message to the terminal device if it is an RRC recovery scenario. Alternatively, in either scenario, the first access network device can send an RRC establishment message to the terminal device to directly fall back from the RRC recovery or RRC re-establishment process to the RRC establishment process, thereby restoring the terminal device's data transmission faster and reducing the interruption time of user data transmission for the terminal device.

[0146] Another embodiment of this application provides a communication method; please refer to [link to relevant documentation]. Figure 7 Here is a flowchart of the method. In the following description, this method will be applied to... Figure 1 The illustrated communication system serves as an example. Furthermore, this method can be executed by two communication devices, such as a first access network device and a second access network device. The first and second access network devices can be base stations or communication devices capable of supporting the functions required for the base station to implement this method.

[0147] This embodiment can be applied to RRC recovery or RRC re-establishment scenarios. For details, please refer to [link / reference needed]. Figure 3 The corresponding descriptions of the embodiments shown will not be repeated in this embodiment.

[0148] S710, the first access network device sends a first message to the second access network device to request the retrieval of the context information of the terminal device.

[0149] Accordingly, the second access network device receives the first message. This first message includes a first cell identifier, which is a unique cell identifier of the target cell within the PLMN range for the terminal device under the first access network device; that is, the cellIdentity of the target cell. The first message may be a RETRIEVEUE CONTEXT REQUEST message between base stations.

[0150] It is understandable that step S710 can be executed during RRC recovery or RRC rebuild scenarios; see details below. Figure 3 The corresponding descriptions in the illustrated embodiments will not be repeated in this embodiment.

[0151] S720 and the second access network device determine the target cell based on the CellIdentity of the target cell and the PLMN identifier of the terminal device in the second access network device, and generate a key using the PCI and downlink ARFCN of the target cell.

[0152] In one possible implementation, the second access network device first identifies candidate target cells based on the CellIdentity of the received target cell. In a network sharing scenario, the second access network device may identify one or more candidate target cells. That is, the CellIdentity of these one or more candidate target cells is the same as the CellIdentity of the received target cell, but the multiple candidate target cells have their own different PLMN identifiers.

[0153] The second access network device stores the context information of the terminal device. This context information includes the identifier of the PLMN of the terminal device in the second access network device, or the identifier of the serving PLMN or the selected PLMN of the terminal device when the second access network device provides services to the terminal device. Considering that the terminal device generally does not change its PLMN, that is, the PLMN of the terminal device under the first access network device is usually the same as the PLMN under the second access network device, in this embodiment, if multiple candidate target cells are identified, the second access network device can select a candidate target cell with the same PLMN identifier as the terminal device in the second access network device as the target cell, and then generate a key based on the PCI and ARFCN of the target cell. This can improve the accuracy of the generated key, thereby reducing the failure rate of the RRC recovery process or RRC re-establishment process due to key inconsistency.

[0154] Optionally, if none of the candidate target cells are the same as the PLMN under the second access network device for the terminal device, then according to... Figure 5 The corresponding implementation involves generating keys based on the PCI and downlink ARFCN of each candidate target cell, and sending these multiple keys and the corresponding cell information of the candidate target cells to the first access network device; or step S730 can be omitted, and instead, it can be performed according to... Figure 6 In the corresponding implementation, the second access network device refuses to transfer the context information of the terminal device and sends a third message to the first access network device. Taking Table 1 as an example, if the first message includes the CellIdentity (2) of the target cell, based on the CellIdentity of the target cell, the second access network device identifies two candidate target cells under the first access network device with CellIdentity (2), namely cell 1 and cell 2. If the PLMN of the terminal device in the second access network device is PLMN 1, then the second access network device selects the PCI and downlink ARFCN of cell 2 to generate the key; if the PLMN of the terminal device in the second access network device is PLMN 2, then the second access network device selects the PCI and downlink ARFCN of cell 1 to generate the key.

[0155] Optionally, if only one candidate target cell is identified, the PCI and ARFCN of this candidate target cell are used directly to generate the key, that is, it is not necessary to check whether the PLMN identifier of the candidate target cell is the same as the PLMN identifier of the terminal device in the second access network device.

[0156] In another possible implementation, the second access network device determines the target cell based on the received CellIdentity of the target cell and the PLMN identifier of the terminal device on the second access network device. Specifically, a cell identified as the target cell by the second access network device must meet two conditions: first, the CellIdentity of the cell is the same as the received CellIdentity of the target cell; and second, the PLMN identifier of the cell is the same as the PLMN identifier of the terminal device on the second access network device. If a cell meets these conditions, it is identified as the target cell. That is, the second access network device identifies a cell with the received CellIdentity of the target cell and the PLMN identifier of the terminal device on the second access network device as the target cell. Then, the second access network device generates a key based on the PCI and downlink ARFCN of the target cell. Optionally, the target cell can also be limited to the condition that it is a cell under the first access network device. That is, the second access network device identifies a cell under the first access network device with the received CellIdentity of the target cell and the PLMN identifier of the terminal device on the second access network device as the target cell, thereby enabling more accurate identification of the target cell. Considering that terminal devices generally do not change the PLMN (i.e., the PLMN of the terminal device under the first access network device is usually the same as the PLMN under the second access network device), this processing can improve the accuracy of the generated key, thereby reducing the failure rate of the RRC recovery or RRC re-establishment process due to key inconsistency. If no cell meets the above conditions, then it can be handled according to... Figure 5 The corresponding implementation involves generating keys based on the PCI and downlink ARFCN of each candidate target cell, and sending these multiple keys and the corresponding cell information of the candidate target cells to the first access network device; or step S730 can be omitted, and instead, it can be performed according to... Figure 6 In the corresponding implementation, the second access network device refuses to transfer the context information of the terminal device and sends a third message to the first access network device.

[0157] S730, the second access network device sends a second message to the first access network device to transfer the context information of the terminal device to the first access network device.

[0158] Accordingly, the first access network device receives the second message. The second message includes the key generated in step S720.

[0159] The second message can be a UE context retrieval response message between base stations (i.e., RETRIEVE UE CONTEXTRESPONSE).

[0160] Understandable, Figures 3-7 The corresponding embodiments can be implemented individually or in combination. For example, when the first message includes the first information, they can be implemented according to... Figure 3 or Figure 4 The description related to the corresponding embodiment is executed; when the first message does not include the first information, it can be performed according to... Figures 5-7 The description related to any embodiment is executed. For example, when the first message does not include the first information and there is no candidate target cell among the plurality of candidate target cells that is the same as the PLMN of the terminal device under the second access network device, then it can be performed according to... Figure 5 or Figure 6 The corresponding implementation description is executed as follows: When there is a candidate target cell among the multiple candidate target cells that is the same as the PLMN under the second access network device of the terminal device, it can be performed according to... Figure 7 The description related to the corresponding implementation examples will be executed.

[0161] The apparatus used to implement the above method in the embodiments of this application is described below with reference to the accompanying drawings. Therefore, the content above can be used in subsequent embodiments, and repeated content will not be described again.

[0162] Figure 8 This is a schematic block diagram of a communication device 800 provided in an embodiment of this application. The communication device 800 can correspondingly implement the functions or steps implemented by the first access network device or the second access network device in the various method embodiments described above.

[0163] In some possible implementations, the communication device may include one or more of a transmitting unit 810, a receiving unit 820, and a processing unit 830. Optionally, it may also include a storage unit, which can be used to store instructions (code or program) and / or data. The transmitting unit 810, the receiving unit 820, and the processing unit 830 may be coupled to the storage unit; for example, the processing unit 830 may read instructions (code or program) and / or data from the storage unit to implement a corresponding method. The aforementioned units may be set independently or partially or completely integrated.

[0164] In some possible implementations, the communication device 800 can correspondingly implement the operations and functions of the first access network device in the above method embodiments. For example, the communication device 800 can be the first access network device, or it can be a component (e.g., a chip or circuit) applied in the first access network device. The transmitting unit 810 and the receiving unit 820 can be used to perform all the receiving or transmitting operations performed by the first access network device in the above method embodiments, and / or other processes to support the technology described herein. The processing unit 830 is used to perform all operations performed by the first access network device in the above method embodiments other than the transmitting and receiving operations, and / or other processes to support the technology described herein.

[0165] In some embodiments, the sending unit 810 is configured to send a first message to the second access network device, wherein the first message is used to request the transfer of context information of the terminal device. The first message includes first information, which includes the PLMN identifier information of the target cell to which the terminal device belongs under the first access network device, or the CGI of the target cell of the terminal device under the first access network device, or the first PCI and the first ARFCN. The first PCI is the physical cell identifier of the target cell of the terminal device under the first access network device, and the first downlink ARFCN is the downlink ARFCN of the target cell of the terminal device under the first access network device. The receiving unit 820 is configured to receive a second message from the second access network device, wherein the second message is used to transfer the context information of the terminal device. The second message includes a key, which is generated by the second access network device based on the first information, or generated based on the PCI and downlink ARFCN of the target cell determined by the first information. The processing unit 830 is configured to communicate with the terminal device based on the key in the second message. See details below. Figure 3 , Figure 4 The descriptions of the corresponding method embodiments are not repeated here.

[0166] In other embodiments, the sending unit 810 is configured to send a first message to the second access network device, wherein the first message is used to request the transfer of context information of the terminal device, and the first message includes a first cell identifier, which is a unique cell identifier of the target cell of the terminal device under the first access network device within the Public Land Mobile Network (PLMN) range; the receiving unit 820 is configured to receive a second message from the second access network device, wherein the second message is used to transfer the context information of the terminal device, and the second message includes multiple keys and cell information of candidate target cells corresponding to the multiple keys, wherein the candidate target cells are cells with the first cell identifier; the processing unit 830 is configured to select a key corresponding to the target cell based on the cell information of the candidate target cells, and communicate with the terminal device based on the selected key. See details below. Figure 5The descriptions of the corresponding method embodiments are not repeated here.

[0167] It should be understood that the processing unit 830 in the embodiments of this application can be implemented by at least one processor or processor-related circuit components, and the sending unit 810 and the receiving unit 820 can be implemented by a transceiver or transceiver-related circuit components or a communication interface.

[0168] In some possible implementations, the communication device 800 can correspondingly implement the operations and functions of the second access network device in the above method embodiments. For example, the communication device 800 can be the second access network device, or it can be a component (e.g., a chip or circuit) applied in the second access network device. The transmitting unit 810 and the receiving unit 820 can be used to perform all the receiving or transmitting operations performed by the second access network device in the above method embodiments, and / or other processes to support the technology described herein. The processing unit 830 is used to perform all operations performed by the second access network device in the above method embodiments except for the transmitting and receiving operations, and / or other processes to support the technology described herein.

[0169] In some embodiments, the receiving unit 820 is configured to receive a first message from a first access network device, wherein the first information includes the PLMN identifier information of the target cell to which the terminal device belongs under the first access network device, or the CGI of the target cell of the terminal device under the first access network device, or the first PCI and the first ARFCN, wherein the first PCI is the physical cell identifier of the target cell of the terminal device under the first access network device, and the first downlink ARFCN is the downlink ARFCN of the target cell of the terminal device under the first access network device; the processing unit 830 is configured to generate a key based on the first information or generate a key based on the PCI and downlink ARFCN of the target cell determined by the first information; the sending unit 810 is configured to send a second message to a second access network, wherein the second message is used to transfer the context information of the terminal device, and the second message includes the generated key. See details below. Figure 3 , Figure 4 The descriptions of the corresponding method embodiments are not repeated here.

[0170] In other embodiments, the receiving unit 820 is configured to receive a first message from a first access network device, wherein the first message includes a first cell identifier, which is a unique cell identifier of the target cell of the terminal device under the first access network device within the Public Land Mobile Network (PLMN) range; the processing unit 830 is configured to determine multiple candidate target cells with the first cell identifier and generate multiple keys corresponding to the multiple candidate target cells; the sending unit 810 is configured to send a second message to a second access network, wherein the second message is used to transfer the context information of the terminal device, and the second message includes multiple keys and cell information of the candidate target cells corresponding to the multiple keys respectively. See details for further information. Figure 5 The descriptions of the corresponding method embodiments are not repeated here.

[0171] In other embodiments, the receiving unit 820 is configured to receive a first message from a first access network device, wherein the first message includes a first cell identifier, which is a unique cell identifier of the target cell of the terminal device under the first access network device within the Public Land Mobile Network (PLMN) range; the processing unit 830 is configured to determine that when multiple candidate target cells with the first cell identifier exist, the transfer of the terminal device's context information is rejected; and the sending unit 810 is configured to send a third message to a second access network, wherein the third message is used to indicate that the transfer of the terminal device's context information has failed. See details below. Figure 6 The descriptions of the corresponding method embodiments are not repeated here.

[0172] In other embodiments, the receiving unit 820 is configured to receive a first message from a first access network device, wherein the first message includes a first cell identifier, which is a unique cell identifier of the target cell of the terminal device under the first access network device within the Public Land Mobile Network (PLMN) range; the processing unit 830 is configured to determine the target cell based on the first cell identifier and the PLMN identifier of the terminal device under the second access network device, for example, the processing unit 830 determines the cell under the first access network device that has the first cell identifier and the PLMN identifier of the second access network device as the target cell; the processing unit 830 is further configured to generate a key based on the PCI and downlink ARFCN of the target cell; the sending unit 810 is configured to send a second message to the second access network, wherein the second message is used to transfer the context information of the terminal device, and the second message includes the generated key. See details [link to relevant documentation]. Figure 7 The descriptions of the corresponding method embodiments are not repeated here.

[0173] It should be understood that the processing unit 830 in the embodiments of this application can be implemented by a processor or processor-related circuit components, and the sending unit 810 and the receiving unit 820 can be implemented by a transceiver or transceiver-related circuit components.

[0174] The storage unit in the above embodiments can be implemented using a memory.

[0175] like Figure 9 The diagram shows a communication device 900 provided in an embodiment of this application. The communication device 900 can be an access network device capable of implementing the functions of the first or second access network device in the method provided in this application embodiment; the communication device 900 can also be a device capable of supporting the first or second access network device in implementing the corresponding functions in the method provided in this application embodiment. The communication device 900 can be a chip system. In this embodiment, the chip system can be composed of chips or may include chips and other discrete components.

[0176] The communication device 900 includes at least one processor 920, used to implement or support the communication device 900 in implementing the functions of the first access network device or the second access network device in the methods provided in the embodiments of this application. See the detailed description in the method examples for specific examples, which will not be repeated here.

[0177] The communication device 900 may further include at least one memory 930 for storing program instructions and / or data. The memory 930 is coupled to the processor 920. The coupling in this embodiment is an indirect coupling or communication connection between devices, units, or modules, and may be electrical, mechanical, or other forms, for information exchange between devices, units, or modules. The processor 920 may operate in conjunction with the memory 930. The processor 920 may execute the program instructions and / or data stored in the memory 930 to cause the communication device 900 to implement a corresponding method. Optionally, at least one of the at least one memory may be included in the processor.

[0178] The communication device 900 may further include a communication interface 910 for communicating with other devices via a transmission medium, thereby enabling devices in the communication device 900 to communicate with other devices. For example, when the communication device is a first access network device or a second access network device, the other device is a terminal device. The processor 920 can use the communication interface 910 to send and receive data. Specifically, the communication interface 910 may be a transceiver. For example, the aforementioned sending unit 810 and receiving unit 820 constitute the communication interface 910.

[0179] This application embodiment does not limit the specific connection medium between the communication interface 910, processor 920, and memory 930. Exemplarily, this application embodiment... Figure 9 The memory 930, processor 920, and communication interface 910 are connected via a bus 940. Figure 9The connections between other components are shown in bold and are for illustrative purposes only, not as limiting information. The bus can be divided into address bus, data bus, control bus, etc. For ease of illustration, Figure 9 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0180] In the embodiments of this application, the processor 920 may be a general-purpose processor, a digital signal processor, an application-specific integrated circuit, a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components, and may implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor may be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of this application can be directly manifested as being executed by a hardware processor, or executed by a combination of hardware and software modules within the processor.

[0181] In this embodiment, the memory 930 can be non-volatile memory, such as a hard disk drive (HDD) or a solid-state drive (SSD), or it can be volatile memory, such as random-access memory (RAM). Memory is any other medium capable of carrying or storing desired program code in the form of instructions or data structures, and accessible by a computer, but is not limited thereto. The memory in this embodiment can also be a circuit or any other device capable of implementing storage functions, used to store program instructions and / or data.

[0182] Figure 10 A simplified schematic diagram of a communication device is shown. This is for ease of understanding and illustration. Figure 10 In this context, the communication device is exemplified by an access network device. This access network device can be applied to, for example... Figure 1 In the system shown, it is possible to Figure 1The network device 1000 performs the functions of the access network device in the above method embodiments. The access network device 1000 may include one or more radio frequency (RF) units 1010, such as a remote radio unit (RRU) or an active antenna unit (AAU), and one or more baseband units (BBU) (also referred to as digital units, DU) 1020. The RF unit 1010 may be called a communication module; optionally, it may also be called a transceiver, transceiver circuit, or transceiver, etc., and may include at least one antenna 1011 and an RF module 1012. The RF unit 1010 is mainly used for transmitting and receiving RF signals and converting RF signals to baseband signals. The BBU 1020 is mainly used for baseband processing and controlling the access network device. The RF unit 1010 and the BBU 1020 may be physically arranged together or physically separated, i.e., a distributed access network device.

[0183] The BBU 1020 serves as the control center for the access network equipment, also known as the processing module. It primarily performs baseband processing functions such as channel coding, multiplexing, modulation, and spread spectrum. For example, the BBU 1020 (processing module) can control the access network equipment to execute the operation procedures described in the above method embodiments.

[0184] In one example, the BBU 1020 can consist of one or more boards. These boards can collectively support a single access standard radio access network (such as an LTE or NR network), or they can each support different access standards radio access networks (such as LTE, NR, or other network standards). The BBU 1020 also includes a memory 1021 and a processor 1022. The memory 1021 stores necessary instructions and data. The processor 1022 controls the access network device to perform necessary actions, such as controlling the access network device to execute the operation flow related to the access network device in the above method embodiments. The memory 1021 and processor 1022 can serve one or more boards. That is, each board can have its own memory and processor, or multiple boards can share the same memory and processor. Furthermore, each board can also have necessary circuitry.

[0185] This application also provides a communication system. Specifically, the communication system may include a first access network device and a second access network device, or it may include multiple first access network devices and multiple second access network devices. Optionally, the communication system may also include at least one terminal device. Exemplarily, the communication system includes components for implementing the above... Figure 3The first access network device and the second access network device that perform the relevant functions, or the communication system includes devices for implementing the above. Figure 4 The first access network device and the second access network device that perform the relevant functions, or the communication system includes devices for implementing the above. Figure 5 The first access network device and the second access network device that perform the relevant functions, or the communication system includes devices for implementing the above. Figure 6 The first access network device and the second access network device that perform the relevant functions, or the communication system includes devices for implementing the above. Figure 7 The first access network device and the second access network device that perform the relevant functions, or the communication system includes devices for implementing the above. Figures 2 to 7 The embodiments of at least two figures in the diagram relate to the functions of a first access network device and a second access network device.

[0186] This application also provides a computer-readable storage medium, including instructions that, when executed on a computer, cause the computer to perform... Figure 3 , Figure 4 , Figure 5 , Figure 6 or Figure 7 The method executed by the first access network device or the second access network device.

[0187] This application also provides a computer program product, including instructions that, when run on a computer, cause the computer to perform... Figure 3 , Figure 4 , Figure 5 , Figure 6 or Figure 7 The method executed by the first access network device or the second access network device.

[0188] This application provides a chip system including a processor and potentially a memory, for implementing the functions of the first access network device and the second access network device in the aforementioned method. The chip system can be composed of chips or may include chips and other discrete components.

[0189] It should be understood that the terms "system" and "network" in the embodiments of this application can be used interchangeably. "At least one" means one or more, and "more than one" means two or more. "And / or" describes the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, or B exists alone, where A and B can be singular or plural. The character " / " generally indicates that the related objects before and after are in an "or" relationship. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can mean: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or multiple.

[0190] Furthermore, unless otherwise stated, the ordinal numbers such as "first" and "second" mentioned in the embodiments of this application are used to distinguish multiple objects and are not used to limit the order, timing, priority, or importance of multiple objects. For example, "first message" and "second message" are only used to distinguish different messages, and do not indicate that the two messages are different in priority, sending order, or importance.

[0191] It should be understood that the processor mentioned in the embodiments of this application can be a CPU, or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor can be a microprocessor or any conventional processor.

[0192] It should also be understood that the memory mentioned in the embodiments of this application can be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. The non-volatile memory can be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. The volatile memory can be random access memory (RAM), which is used as an external cache. By way of example, but not limitation, many forms of RAM are available, such as 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 linked dynamic random access memory (SLDRAM), and direct rambus RAM (DR RAM).

[0193] 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, or discrete hardware component, the memory (storage module) is integrated into the processor.

[0194] It should be noted that the memories described herein are intended to include, but are not limited to, these and any other suitable types of memories.

[0195] It should be understood that in the various embodiments of this application, the order of the above-mentioned processes does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0196] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0197] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0198] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0199] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0200] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0201] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, as 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, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium accessible to a computer or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., a solid-state disk (SSD)).

[0202] The above description is merely a specific embodiment of this application, but the protection scope of the embodiments of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the embodiments of this application should be included within the protection scope of the embodiments of this application. Therefore, the protection scope of the embodiments of this application should be determined by the protection scope of the claims.

Claims

1. A communication method characterized by comprising: The method comprises: The second access network device receives a first message from the first access network device, wherein the first message is used for requesting to transfer context information of a terminal device, and the first message comprises first information, the first information comprises public land mobile network (PLMN) identification information to which a target cell under the first access network device belongs to the terminal device, or the first information comprises a cell global identification (CGI) of the target cell under the first access network device to the terminal device; The second access network device generates a key based on the first information; The second access network device sends a second message to the first access network device, wherein the second message is used for transferring the context information of the terminal device, and the second message comprises the key; The second access network device generates a key based on the first information comprises: The second access network device determines the target cell based on the PLMN identification information or the CGI; The second access network device generates the key based on a PCI and a downlink ARFCN of the target cell.

2. The method of claim 1, wherein: The first message is a retrieve user equipment context request message, and the second message is a retrieve user equipment context response message.

3. A communication method characterized by comprising: The method comprises: The first access network device sends a first message to a second access network device, wherein the first message is used for requesting to transfer context information of a terminal device, and the first message comprises first information, the first information comprises public land mobile network (PLMN) identification information to which a target cell under the first access network device belongs to the terminal device, or the first information comprises a cell global identification (CGI) of the target cell under the first access network device to the terminal device; The first access network device receives a second message from the second access network device, wherein the second message is used for transferring the context information of the terminal device, and the second message comprises a key, which is generated based on the first information; The first access network device communicates with the terminal device based on the key.

4. The method of claim 3, wherein: The first message is a retrieve user equipment context request message, and the second message is a retrieve user equipment context response message.

5. The method according to claim 3 or 4, characterized in that, Before the first access network device sends the first message to the second access network device, the method further comprises: The first access network device receives a radio resource control (RRC) resume request message or an RRC reestablishment request message from the terminal device.

6. A communication method characterized by comprising: The method comprises: The second access network device receives a first message from the first access network device, wherein the first message is used for requesting to transfer context information of a terminal device, and the first message comprises a first cell identification, which is a cell identification unique in a public land mobile network (PLMN) range of a target cell under the first access network device to the terminal device; The second access network device determines a plurality of candidate target cells with the first cell identification; The second access network device generates a plurality of keys corresponding to the plurality of candidate target cells; The second access network device sends a second message to the first access network device, wherein the second message is used to transfer context information of the terminal device, and the second message includes the plurality of keys and cell information of candidate target cells corresponding to the plurality of keys respectively.

7. A communication method characterized by comprising: The method comprises: The first access network device sends a first message to the second access network device, wherein the first message is used to request to transfer context information of a terminal device, and the first message includes a first cell identifier which is a cell identifier of a target cell of the terminal device under the first access network device and is unique in a public land mobile network (PLMN) range; The first access network device receives a second message from the second access network device, wherein the second message is used to transfer context information of the terminal device, and the second message includes a plurality of keys and cell information of candidate target cells corresponding to the plurality of keys respectively, and the candidate target cells are cells having the first cell identifier; The first access network device selects a key corresponding to the target cell based on the cell information of the candidate target cells; The first access network device communicates with the terminal device based on the key.

8. A communication method characterized by comprising: The method comprises: The second access network device receives a first message from the first access network device, wherein the first message is used to request to transfer context information of a terminal device, and the first message includes a first cell identifier which is a cell identifier of a target cell of the terminal device under the first access network device and is unique in a public land mobile network (PLMN) range; The second access network device determines the target cell based on the first cell identifier and a PLMN identifier of the terminal device in the second access network device; The second access network device generates a key based on a physical cell identifier (PCI) and a downlink absolute radio frequency channel number (ARFCN) of the target cell; The second access network device sends a second message to the first access network device, wherein the second message is used to transfer context information of the terminal device, and the second message includes the key.

9. A communications device, characterized by The apparatus comprises at least one unit for implementing the method of any one of claims 1 to 8.

10. A communications device, characterized by The apparatus comprises at least one processor and a memory; The memory is configured to store program code; The processor is configured to execute the program code to enable the communication apparatus to perform the method of any one of claims 1 to 8.

11. A communication system, characterized by The communication system comprises a communication apparatus performing the communication method of any one of claims 1 to 2 and a communication apparatus performing the communication method of any one of claims 3 to 5, or a communication apparatus performing the communication method of claim 6 and a communication apparatus performing the communication method of claim 7, or a communication apparatus performing the communication method of claim 8.

12. A computer-readable storage medium, characterized in that, The computer readable storage medium stores a computer program which, when executed, causes the method of any one of claims 1 to 8 to be implemented.

13. A computer program product, characterised in that, The computer program product comprises instructions which, when executed, result in the method of any one of claims 1 to 8 being implemented.

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