Information transmission method and device and computer readable storage medium

Abstract

An information transmission method and apparatus, and a computer readable storage medium, the information transmission method comprising: in response to a terminal device being switched to a target cell, sending a key corresponding to a first cell to the first cell; the first cell is a candidate cell of the terminal device, and the first cell and the target cell respectively belong to different centralized units (CU). By adopting the scheme, the network equipment can send the corresponding key to the first cell belonging to the different CU from the target cell after the terminal equipment is switched to the target cell, so that the first cell can acquire the key used when the terminal equipment subsequently accesses the first cell.

Description

Technical Field

[0001] The present invention relates to the field of wireless communication technologies, and in particular to an information transmission method and device, and a computer-readable storage medium. Background Art

[0002] New Radio (NR) systems introduce continuous handover solutions, such as Layer 1 / L2-Triggered Mobility (LTM) handover. Network equipment configures multiple candidate cells for a terminal device and triggers the terminal device to switch to the target cell via a Media Access Control Element (MAC CE). The terminal device then retains other candidate cells for subsequent handovers.

[0003] As communication technology evolves, in subsequent communication protocol versions, candidate cells may belong to different Centralized Units (CUs), and different CUs may correspond to different keys. Because the handover path of a terminal device is unpredictable, it is difficult for the network device to know the key used by the terminal device to last access the CU, which can result in the terminal device being unable to access the new CU. Summary of the Invention

[0004] The purpose of the embodiments of the present invention is to provide an information transmission method to achieve forward transmission of a key.

[0005] In a first aspect, the present invention provides an information transmission method, comprising: responding to a terminal device switching to a target cell, and sending a key corresponding to a first cell to the first cell; the first cell is a candidate cell of the terminal device, and the first cell and the target cell belong to different centralized units CU respectively.

[0006] When the target cell detects that the terminal device has switched to the target cell, it sends the key corresponding to the first cell to the first cell. In this way, the first cell can learn the key used by the terminal device when it subsequently accesses the target cell.

[0007] Optionally, the key corresponding to the first cell is derived based on the key of the target cell and information of the first cell.

[0008] Optionally, the first cell information includes at least one of the following: a physical cell identifier of the first cell, and a downlink frequency of the first cell.

[0009] The target cell can determine the key corresponding to the first cell based on the key of the target cell, the physical cell identifier of the first cell, and the downlink frequency of the first cell. If the terminal device accesses the first cell from the target cell, the terminal device can also determine the key used in the first cell based on the key of the target cell, the physical cell identifier of the first cell, and the downlink frequency of the first cell to complete the cell handover.

[0010] Optionally, the target cell can also obtain the key corresponding to the target cell sent by the serving cell; the serving cell is the cell that the terminal device last accessed before switching to the target cell; based on the key corresponding to the target cell, the wireless resource control RRC reconfiguration completion sent by the terminal device is decrypted.

[0011] Before switching to the target cell, the target cell can obtain the target cell key sent by the serving cell. Then, after the terminal device accesses the target cell, it can decrypt the RRC reconfiguration completion message sent by the terminal device based on the obtained target cell key, ensuring that the terminal device can access normally.

[0012] Optionally, the target cell may obtain and store the key sent by the second cell in response to the terminal device switching from the target cell to the second cell, where the second cell is selected from the first cell. The network device may also delete the key previously used by the target cell.

[0013] Therefore, when the terminal device switches to the second cell, the target cell can also update the stored key.

[0014] Optionally, the target cell may further configure the corresponding configuration layer 1 or layer 2 triggering mobility LTM conditional handover execution condition for the candidate cell; or, update the corresponding LTM conditional handover execution condition for the candidate cell.

[0015] Optionally, the target cell may obtain the CU to which the candidate cell belongs, or obtain the candidate cells corresponding to other CUs configured for the terminal device, or obtain all candidate cells configured for the terminal device.

[0016] Optionally, the target cell may obtain the CU to which the candidate cell belongs when configuring LTM conditional switching; or, when configuring LTM conditional switching for the terminal device, obtain the candidate cells corresponding to other CUs.

[0017] The target cell may obtain the CU to which the candidate cell belongs, or the target cell may obtain the candidate cells corresponding to other CUs configured for the terminal device, or the target cell may obtain all candidate cells configured for the terminal device. Thus, the target cell may determine which candidate cells are the first cell and then send the corresponding key to the first cell.

[0018] In a second aspect, the present invention provides another information transmission method, including: in response to switching to a first cell, using the key corresponding to the first cell to access the first cell; the first cell is a candidate cell for the terminal device, and the first cell and the target cell belong to different centralized units respectively, and the target cell is the cell that the terminal device last accessed before switching to the first cell; and the first cell has obtained the key corresponding to the first cell sent by the target cell before the terminal device accesses.

[0019] In a third aspect, the present invention provides an information transmission device, comprising: a sending unit, for sending a key corresponding to a first cell to the first cell in response to a terminal device switching to a target cell; the first cell is a candidate cell of the terminal device, and the first cell and the target cell belong to different centralized units CU respectively.

[0020] In a fourth aspect, the present invention provides another information transmission device, including: a processing unit, for accessing the first cell using a key corresponding to the first cell in response to switching to the first cell; the first cell is a candidate cell for the terminal device, and the first cell and the target cell belong to different centralized units respectively, and the target cell is the cell that the terminal device last accessed before switching to the first cell; and the first cell has obtained the key corresponding to the first cell sent by the target cell before the terminal device accesses.

[0021] In a fifth aspect, the present invention also provides a computer-readable storage medium, which is a non-volatile storage medium or a non-transient storage medium, on which a computer program is stored, and the computer program is executed by a processor to perform the steps of any of the above-described methods.

[0022] In a sixth aspect, the present invention also provides another information transmission device, comprising a memory and a processor, wherein the memory stores a computer program that can be run on the processor, and the processor executes the steps of any of the above-mentioned information transmission methods when running the computer program. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a flow chart of LTM condition switching;

[0024] Figure 2 is a flow chart of an information transmission method according to an embodiment of the present invention;

[0025] Figure 3 1 is a schematic diagram of a path for LTM conditional switching in an embodiment of the present invention;

[0026] Figure 4 It is a structural diagram of an information transmission device in an embodiment of the present invention. DETAILED DESCRIPTION

[0027] In R18, all candidate cells use the same key during LTM handover. In R19, different candidate cells may belong to different CUs and require different keys.

[0028] For example, serving cell 0, candidate cell 1, candidate cell 2, and candidate cell 3 all belong to centralized unit CU1 and use key 1. Candidate cells 4 and 5 belong to centralized unit CU2 and need to use a key different from key 1. Candidate cells 6 and 7 belong to centralized unit CU3 and need to use a key different from key 1.

[0029] When a terminal device performs LTM conditional handover from cell 0 to cell 6, different handover paths may exist. The first handover path is: the terminal device first switches to cell 4, then switches to cell 6. Cell 4 uses key 2, which is derived based on key 1, cell 4's physical cell identifier (PCI), and cell 4's downlink frequency (DL frequency) (the specific derivation algorithm can be based on the algorithm provided in the existing protocol). Cell 6 uses key 3, which is derived based on key 2, cell 6's PCI, and cell 6's downlink frequency. The second handover path is: the terminal device switches directly from cell 0 to cell 6. Cell 6 uses key 4, which is derived based on key 1, cell 6's PCI, and cell 6's downlink frequency.

[0030] For the first handover path and the second handover path, the key 3 and key 4 used by cell 6 are different. It can be seen that for different handover paths, the keys derived from the same candidate cell may be different.

[0031] When there are multiple candidate cells, the terminal device may have many handover paths, making it difficult to pre-derive all possible keys and store them in the corresponding candidate cells. When the terminal device performs LTM conditional handover and accesses the target cell, it sends the Radio Resource Control (RRC) reconfiguration completion message via the Dedicated Control Channel (DCCH). The DCCH is encrypted using the target cell's key and encryption algorithm, and integrity protected using the target cell's key and integrity protection algorithm.

[0032] If the target cell to which the terminal device accesses does not have a key, the information reported by the terminal device may not be fully parsed and trusted, and the target cell cannot obtain the key from the CU to which the terminal device last accessed.

[0033] In the embodiment of the present invention, upon detecting that the terminal device has switched to the target cell, the target cell sends the key corresponding to the first cell to the first cell, thereby enabling the first cell to learn the key used by the terminal device when it subsequently accesses the target cell.

[0034] In order to make the above-mentioned objects, features and beneficial effects of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0035] The terminal device described in the embodiments of the present application is a device with wireless communication capabilities, and may also be referred to as a terminal, mobile station (MS), mobile terminal (MT), access terminal equipment, vehicle-mounted terminal equipment, industrial control terminal equipment, user equipment (UE), UE unit, UE station, mobile station, remote station, remote terminal equipment, mobile device, wireless communication device, UE agent, or UE device. The UE can be fixed or mobile. It should be noted that the UE can support at least one wireless communication technology, such as LTE, NR, etc. Exemplarily, the UE may be a mobile phone, a tablet computer, a desktop computer, a laptop computer, an all-in-one computer, an in-vehicle terminal, a virtual reality (VR) UE, an augmented reality (AR) UE, a wireless terminal in industrial control, a wireless terminal in self-driving, a wireless terminal in remote medical surgery, a wireless terminal in a smart grid, a wireless terminal in transportation safety, a wireless terminal in a smart city, a wireless terminal in a smart home, a cellular phone, a cordless phone, a session initiation protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA), a handheld device with wireless communication capabilities, a computing device or other processing device connected to a wireless modem, a wearable device, a UE in a future mobile communication network, or a UE in a future evolved public mobile land network (PLMN), etc. In some embodiments of the present application, the UE may also be a device with transceiver functions, such as a chip system, wherein the chip system may include a chip and may also include other discrete devices.

[0036] In the embodiment of the present application, a network device is a device that provides wireless communication functions for a terminal device, and may also be referred to as a radio access network (RAN) device, an access network element, an access network device, etc. The network device may support at least one wireless communication technology, such as LTE, NR, etc. For example, the network device includes, but is not limited to: a next-generation base station (gNB) in 5G, an evolved node B (eNB), a radio network controller (RNC), a node B (NB), a base station controller (BSC), a base transceiver station (BTS), a home base station (e.g., home evolved node B, or home node B, HNB), a baseband unit (BBU), a transmitting and receiving point (TRP), a transmitting point (TP), a mobile switching center, etc. The network device may also be a wireless controller, a centralized unit (CU), and / or a distributed unit (DU) in a cloud radio access network (CRAN) scenario, or the network device may be a relay station, an access point, an on-board device, a terminal device, a wearable device, a network device in future mobile communications, or a network device in a future evolved PLMN. In some embodiments, the network device may also be a device that provides wireless communication functions for a terminal device, such as a chip system. For example, the chip system may include a chip and may also include other discrete devices.

[0037] In some embodiments, the network device may also communicate with an Internet Protocol (IP) network, such as the Internet, a private IP network, or other data networks.

[0038] In the embodiment of the present invention, before describing the information transmission method provided by the embodiment of the present invention, a brief description is first given of the process of performing LTM switching by the terminal device.

[0039] Reference Figure 1 , a flow chart of LTM conditional switching is given. It can be understood that the following steps 101 to 108 only generally describe the process of LTM conditional switching.

[0040] Step 101: The terminal device sends a measurement report to the network device.

[0041] The terminal device resides in the serving cell. When the terminal device is in the RRC connected state, the network device can configure measurement configuration information for the terminal device. The terminal device can perform measurement operations based on the measurement configuration information. The terminal device detects a serving cell or neighboring cell that meets the reporting conditions and reports a measurement report.

[0042] Step 102: The network device configures candidate cells for the terminal device.

[0043] In a specific implementation, the network device can configure one or more candidate cells for the terminal device through RRC reconfiguration, as well as the switching conditions (or switching execution conditions) corresponding to one or more candidate cells, such as the signal quality threshold of the candidate cell is higher than the preset threshold.

[0044] In addition, the network device can also configure the uplink resources used by the terminal device to report the layer 1 measurement results through RRC reconfiguration.

[0045] For example, the network device configures candidate cells 1 to 7 for the terminal device, candidate cells 1 to 3 belong to CU1, candidate cells 4 to 5 belong to CU2, and candidate cells 6 to 7 belong to CU3.

[0046] In a specific implementation, the network equipment corresponding to the serving cell can clearly indicate to the terminal device the CU or base station to which different candidate cells belong. The network equipment corresponding to the serving cell can also, through configuration information, enable the terminal device to know the candidate cells within the same CU or base station, and thus infer candidate cells belonging to different CUs or base stations. Step 103: The terminal device sends an RRC reconfiguration completion message.

[0047] In a specific implementation, the terminal device receives the RRC reconfiguration and feeds back RRC reconfiguration complete (RRCreconfiguration complete) to the network device.

[0048] Step 104: The terminal device performs uplink and downlink synchronization with the candidate cell.

[0049] In a specific implementation, the terminal device can achieve downlink and uplink synchronization with the candidate cell based on RRC reconfiguration and subsequent Layer 2 signaling and Layer 1 signaling. This step is optional. If uplink synchronization with the candidate cell is required, the serving cell will trigger the terminal device to send a random access preamble to the candidate cell through Layer 1 signaling. The network side obtains the uplink advance TA based on the preamble sent by the terminal device.

[0050] Step 105: The terminal device reports the layer 1 measurement result.

[0051] In a specific implementation, the terminal device may report the layer 1 measurement result of the serving cell and the layer 1 measurement result of at least one candidate cell to the network device.

[0052] Step 106: The network device sends a cell switching command to the terminal device.

[0053] In a specific implementation, the network device determines that the terminal device performs cell switching based on the layer 1 measurement result of the serving cell and the layer 1 measurement result of at least one candidate cell. The network device sends a cell switch command to the terminal device via MAC CE signaling. Step 106 is optional.

[0054] If the terminal device finds that a candidate cell meets the switching execution conditions, the terminal device does not need to perform switching based on the cell switching command sent by the network device, but can directly access the candidate cell that meets the switching execution conditions.

[0055] Step 107: The terminal device performs a random access process.

[0056] In a specific implementation, if the terminal device does not receive the timing advance (TA) of the target cell, the terminal device needs to perform a random access process in the target cell.

[0057] Step 108: The terminal device sends an RRC reconfiguration completion message to the target cell.

[0058] The information transmission method provided in the embodiment of the present invention is described in detail below. Figure 2 , a flowchart of an information transmission method according to an embodiment of the present invention is given.

[0059] In an embodiment of the present invention, the information transmission method provided in the following steps 201 to 202 can be executed by a chip with data processing functions in a network device, or by a chip module with data processing capabilities in a network device, or by a network device. In the following embodiment, the information transmission method is described as an example by a network device. Unless otherwise specified, the above-mentioned network device may refer to the CU or base station corresponding to the target cell.

[0060] In the specific implementation, it can be seen that in the 5G network, the baseband processing unit (Base Band Unit, BBU) is split into a distributed unit (DU) and a centralized unit (CU). Among them, the CU is mainly responsible for non-real-time wireless high-level protocol stack functions, and also supports the sinking of some core network functions and the deployment of edge application services; the DU mainly processes physical layer functions and layer 2 functions with real-time requirements. In some embodiments, the media access layer (MAC) and the radio link control (Radio Link Control, RLC) layer can be processed in the DU, and the packet data convergence protocol (Packet Data Convergence Protocol, PDCP) and RRC layer can be processed in the CU.

[0061] Step 201: In response to a terminal device switching to a target cell, a key corresponding to a first cell is sent to the first cell.

[0062] In a specific implementation, the specific process of the terminal device switching from the serving cell to the target cell can refer to the description of steps 101 to 108 above.

[0063] In the embodiment of the present invention, the network device may learn that the terminal device switches from the serving cell to the target cell. After determining that the terminal device switches to the target cell, the network device may send a key corresponding to the first cell to the first cell.

[0064] In a specific implementation, the first cell may be a candidate cell corresponding to the terminal device, and the first cell and the target cell belong to different CUs respectively.

[0065] For example, when a terminal device accesses serving cell 0, the network device configures candidate cells for the terminal device, including cells 1 to 7. Cells 1 to 3 belong to CU1, cells 4 to 5 belong to CU2, and cells 6 to 7 belong to CU3. Furthermore, the keys corresponding to CU1, CU2, and CU3 are different.

[0066] The terminal device switches from cell 0 to cell 1, where cell 1 is the target cell, and the first cell corresponding to cell 1 includes cells 4 to 5, and cells 6 to 7. Therefore, the network device can send the keys corresponding to cells 4, 5, 6, and 7 to cells 4, 5, 6, and 7, respectively.

[0067] In the embodiment of the present invention, the key corresponding to the first cell may be generated by the network device corresponding to the target cell. It is understandable that the key corresponding to the first cell may also be generated by other network devices or core network devices and sent to the network device corresponding to the target cell.

[0068] In the embodiment of the present invention, the network device may derive the key corresponding to the first cell based on the key of the target cell and the information of the first cell.

[0069] In a specific implementation, the information of the first cell may include at least one of a physical cell identifier (PCI) of the first cell and a downlink frequency of the first cell.

[0070] In some embodiments, the network device may generate a key corresponding to the first cell (i.e., a key used by the terminal device when accessing the first cell) based on the key of the target cell (i.e., the key used by the terminal device in the target cell), the PCI of the first cell, and the downlink frequency of the first cell. Accordingly, when the terminal device switches from the target cell to the first cell, the terminal device may generate a key corresponding to the first cell based on the key of the target cell, the PCI of the first cell, and the downlink frequency of the first cell.

[0071] That is to say, the way in which the terminal device derives the key when switching to the first cell is the same as the way in which the network device derives the key corresponding to the first cell.

[0072] In a specific implementation, after generating the key corresponding to the first cell, the network device may send the key corresponding to the first cell to the first cell.

[0073] For example, the first cell includes cells 4 to 7. The network device may generate a key corresponding to cell 4 and send it to cell 4, generate a key corresponding to cell 5 and send it to cell 5, generate a key corresponding to cell 6 and send it to cell 6, and generate a key corresponding to cell 7 and send it to cell 7.

[0074] In some embodiments, if different first cells belong to the same CU, a corresponding key may be generated based on only one candidate cell of the same CU and sent to all candidate cells corresponding to the CU.

[0075] For example, cell 4 and cell 5 belong to CU2, the target cell is cell 1, and cell 1 belongs to CU1. When the network device detects that the terminal device has switched to cell 1, it can generate a key corresponding to cell 4 based on the key corresponding to cell 1, the PCI of cell 4, and the downlink frequency of cell 4, and send the key corresponding to cell 4 to cells 4 and 5.

[0076] In a specific implementation, when a terminal device accesses a serving cell, it can evaluate all candidate cells and select a candidate cell that meets the handover execution conditions as the target cell. If the target cell selected by the terminal device belongs to the same CU as the serving cell, the terminal device does not need to update the key when switching from the serving cell to the target cell. If the target cell and the serving cell belong to different CUs, the terminal device needs to update the key when switching from the serving cell to the target cell.

[0077] Therefore, when the network device detects that the terminal device accesses the serving cell, if the target cell and the serving cell belong to different CUs, the network device can generate a key corresponding to the target cell and send it to the target cell (in advance). After the terminal device switches to the target cell, the RRC reconfiguration completion sent by the terminal device can be decrypted based on the key corresponding to the target cell.

[0078] For example, when a terminal device accesses serving cell 0, candidate cells for the terminal device include cells 1 to 7. Cells 0 and 1 to 3 belong to CU1, cells 4 to 5 belong to CU2, and cells 6 to 7 belong to CU3. The terminal device determines that the target cell is cell 1.

[0079] When a terminal device switches from cell 0 to cell 1, cell 1 is used as the target cell and no key update is required. After the network device detects that the terminal device has switched to cell 1, it generates keys corresponding to cells 4 to 5 and cells 6 to 7.

[0080] Some time after the terminal device switches to cell 1, it determines that cell 4 meets the switching conditions and switches to cell 4. In this scenario, cell 4 is the target cell, and cells 1-3, 6-7 are the primary cells. Cell 4 is the new serving cell. Cell 4 can decrypt the RRC Reconfiguration Complete message sent by the terminal device using the key previously sent by cell 1.

[0081] In an embodiment of the present invention, if the network device detects that the terminal device switches from the target cell to the second cell, the candidate cell of the terminal device needs to update the key, save the key sent by the second cell, and delete the previously saved key sent by the target cell.

[0082] For example, the target cell is cell 1 and the second cell is cell 4. When the network device detects that the terminal device has switched to cell 1, cell 1 sends the key used by the terminal device for subsequent access to the candidate cells of other CUs. For example, the key obtained by cell 6 is generated based on the key of cell 1 (the key used by the terminal device in cell 1), the PCI of cell 6, and the downlink frequency of cell 6. When the terminal device switches from cell 1 to cell 4, cell 4 sends the key used by the terminal device for subsequent access to the candidate cells of other CUs. In this case, the key of cell 6 needs to be updated. The updated key is generated based on the key of cell 4 (the key used by the terminal device in cell 4), the PCI of cell 6, and the downlink frequency of cell 6.

[0083] In an embodiment of the present invention, the network device may further obtain the CU corresponding to each of all configured candidate cells, or obtain the candidate cells corresponding to other CUs configured for the terminal device (i.e., a CU different from the CU to which the serving cell belongs), or obtain all candidate cells configured for the terminal device. In this way, the network device can know the CU to which each candidate cell belongs.

[0084] In the embodiment of the present invention, the network device may further configure a handover execution condition of the corresponding LTM conditional handover for the candidate cell, or update a handover execution condition of the corresponding LTM conditional handover for the candidate cell.

[0085] In a specific implementation, when configuring LTM conditional handover, the network device can obtain the CU to which the candidate cell belongs, or obtain the candidate cells corresponding to other CUs. For example, when CU1 requests CU2 to configure an LTM candidate cell for the terminal device, CU1 indicates to CU2 the other candidate cells configured by the terminal device, or the CU to which the other candidate cells belong. This allows the network device to determine the CU corresponding to the candidate cell, or the mapping relationship between the candidate cell and the CU.

[0086] The information transmission method provided in the above embodiment of the present invention is described in detail below through specific examples.

[0087] Reference Figure 3 , a schematic diagram of a path of LTM conditional switching in an embodiment of the present invention is given.

[0088] When a terminal device is set to access a serving cell, candidate cells for the terminal device include cells 1 to 7. The serving cell and cells 1 to 3 belong to CU1, cells 4 to 5 belong to CU2, and cells 6 to 7 belong to CU3. The keys corresponding to CU1, CU2, and CU3 are different.

[0089] The terminal device switches from the serving cell to cell 1, which is the target cell for the terminal device. When the terminal device accesses cell 1, it may subsequently switch to any of cells 2 through 7. Since cells 1, 2, and 3 belong to the same CU and use the same key, if the terminal device switches from cell 1 to cell 2, no key update is required. If the terminal device switches from cell 1 to any of cells 4, 5, 6, or 7, a key update is required because cell 1, 4, 5, 6, or 7 do not belong to the same CU.

[0090] The terminal device may switch from cell 1 to any one of cell 4, cell 5, cell 6 and cell 7. Therefore, after the network device determines that the terminal device has switched to cell 1 (the network device may refer to cell 1 or CU1 at this time), it may generate a key corresponding to cell 4, a key corresponding to cell 5, a key corresponding to cell 6 and a key corresponding to cell 7 for cell 4, cell 5, cell 6 and cell 7 respectively.

[0091] Specifically, the network device can derive the key KgNB* for cell 5 based on the key KgNB corresponding to cell 1, the PCI corresponding to cell 5, and the downlink frequency corresponding to cell 5. The network device can derive the key KgNB* for cell 6 based on the key KgNB corresponding to cell 1, the PCI corresponding to cell 6, and the downlink frequency corresponding to cell 6. The key KgNB* for cell 5 is different from the key KgNB* for cell 6. Similarly, the network device can derive the key for Cell 4 and the key for Cell 7. Cell 1 or CU1 then sends the key to the corresponding cell or CU, respectively.

[0092] The terminal device performs an LTM conditional handover from cell 1 to cell 4. The terminal device derives the key used in cell 4 and then sends the RRC reconfiguration completion message to cell 4 during the access process. Because cell 4 has already received the key sent by cell 1 (the key used by the terminal device to access cell 4), cell 4 is able to decrypt and perform integrity protection verification on the RRC reconfiguration completion message, ensuring that the terminal device can access normally.

[0093] After the terminal device switches from cell 1 to cell 4, cell 4 becomes the terminal device's target cell. After the terminal device accesses cell 4, to handle subsequent LTM conditional handovers, cell 4 can derive the keys corresponding to cells 1 to 3 and cells 6 to 7, and then send the keys corresponding to cells 1 to 3 to cells 1 to 3, and the keys corresponding to cells 6 to 7 to cells 6 to 7.

[0094] Cells 1 to 3 and 6 to 7 update the stored keys. Specifically, cells 1 to 3 and 6 to 7 delete the previously stored keys and retain the key sent by cell 4.

[0095] For example, for cells 6 and 7, the previously saved key sent by cell 1 is deleted, and the key sent by cell 4 is retained.

[0096] The terminal device performs LTM conditional switching again, switching from cell 4 to cell 6. Since cell 4 has already sent the key to cell 6 in advance, cell 6 can obtain the key used by the terminal device when the terminal device accesses, allowing the terminal device to access.

[0097] In summary, in this embodiment of the present invention, upon detecting that a terminal device has switched to the target cell, the target cell generates a key corresponding to a first cell belonging to a different CU from the target cell, and sends the key corresponding to the first cell to the first cell. Thus, the first cell can learn the key used by the terminal device when it subsequently accesses the target cell.

[0098] The present invention also provides another information transmission method, comprising: in response to switching to a first cell, accessing the first cell using a key corresponding to the first cell.

[0099] It should be noted that the information transmission method can be executed by a chip with data processing capabilities in the terminal device (such as a baseband chip), or by a chip module with data processing capabilities in the terminal device, or by the terminal device.

[0100] In a specific implementation, the specific concepts of the first cell and the target cell can refer to the description of the information transmission method provided in the above embodiment, and will not be repeated here.

[0101] In a specific implementation, after the terminal device switches from the target cell to the first cell, the key corresponding to the first cell can be used to encrypt and integrity protect the RRC reconfiguration completion, and the encrypted and integrity-protected RRC reconfiguration completion is sent to the first cell. Before the terminal device accesses, the first cell receives the key corresponding to the first cell sent by the target cell. As a result, the first cell uses the corresponding key to process the received RRC reconfiguration completion, and the terminal device accesses the first cell.

[0102] Reference Figure 4 , an information transmission device 40 in an embodiment of the present invention is provided, comprising: a sending unit 401, wherein:

[0103] The sending unit 401 is used to send the key corresponding to the first cell to the first cell in response to the terminal device switching to the target cell; the first cell is a candidate cell of the terminal device, and the first cell and the target cell belong to different centralized units CU respectively.

[0104] In a specific implementation, the specific execution process of the above-mentioned sending unit 401 can correspond to step 201 and will not be repeated here.

[0105] In a specific implementation, the above-mentioned information transmission device 40 can correspond to a chip with a data processing function in a network device, or correspond to a chip module with a data processing function in a network device, or correspond to a network device.

[0106] The present invention also provides another information transmission device, including: a processing unit, for responding to switching to a first cell, using the key corresponding to the first cell to access the first cell; the first cell is a candidate cell for the terminal device, and the first cell and the target cell belong to different centralized units respectively, and the target cell is the cell that the terminal device last accessed before switching to the first cell; and the first cell has obtained the key corresponding to the first cell sent by the target cell before the terminal device accesses.

[0107] In a specific implementation, the above-mentioned information transmission device may correspond to a chip with a data processing function in a terminal device, or correspond to a chip module with a data processing function in a terminal device, or correspond to the terminal device.

[0108] In specific implementations, the modules / units included in the various devices and products described in the above embodiments may be software modules / units or hardware modules / units, or may be partially software modules / units and partially hardware modules / units.

[0109] For example, for each device or product applied to or integrated into a chip, each module / unit contained therein may be implemented in the form of hardware such as circuits, or at least some of the modules / units may be implemented in the form of software programs, which run on a processor integrated inside the chip, and the remaining (if any) modules / units may be implemented in the form of hardware such as circuits; for each device or product applied to or integrated into a chip module, each module / unit contained therein may be implemented in the form of hardware such as circuits, and different modules / units may be located in the same component (such as a chip, circuit module, etc.) or different components of the chip module, or at least some of the modules / units may be implemented in the form of software programs. The element can be implemented in the form of a software program, which runs on the processor integrated inside the chip module, and the remaining (if any) modules / units can be implemented in the form of hardware such as circuits; for various devices and products applied to or integrated in the terminal, the various modules / units contained therein can be implemented in the form of hardware such as circuits, and different modules / units can be located in the same component (for example, chip, circuit module, etc.) or different components in the terminal, or, at least some modules / units can be implemented in the form of a software program, which runs on the processor integrated inside the terminal, and the remaining (if any) modules / units can be implemented in the form of hardware such as circuits.

[0110] An embodiment of the present invention also provides a computer-readable storage medium, which is a non-volatile storage medium or a non-transient storage medium, on which a computer program is stored. When the computer program is run by a processor, the steps of the information transmission method provided in any of the above embodiments are executed.

[0111] An embodiment of the present invention also provides another information transmission device, including a memory and a processor, wherein the memory stores a computer program that can be run on the processor, and when the processor runs the computer program, it executes the steps of the information transmission method provided in any of the above embodiments.

[0112] Those skilled in the art will understand that all or part of the steps in the various methods of the above embodiments can be completed by instructing the relevant hardware through a program, and the program can be stored in a computer-readable storage medium, which may include: ROM, RAM, disk or CD, etc.

[0113] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the scope defined by the claims.

Claims

1. An information transmission method, characterized in that: include: In response to the terminal device switching to the target cell, sending the key corresponding to the first cell to the first cell; The first cell is a candidate cell of the terminal device, and the first cell and the target cell belong to different centralized units CU respectively.

2. The information transmission method according to claim 1, wherein: The key corresponding to the first cell is derived based on the key of the target cell and information of the first cell.

3. The information transmission method according to claim 2, wherein: The first cell information includes at least one of the following: a physical cell identifier of the first cell, and a downlink frequency of the first cell.

4. The information transmission method according to claim 1, wherein: Also includes: Obtaining a key corresponding to the target cell sent by the serving cell; The serving cell is the cell accessed by the terminal device before switching to the target cell; Based on the key corresponding to the target cell, the radio resource control RRC reconfiguration completion sent by the terminal device is decrypted.

5. The information transmission method according to claim 1, wherein: Also includes: In response to the terminal device switching from the target cell to a second cell, acquiring and storing a key sent by the second cell; The second cell is selected from the first cell.

6. The information transmission method according to claim 5, wherein: Also includes: Delete the key previously used by the target cell.

7. The information transmission method according to claim 1, wherein: Also includes: Configuring a handover execution condition for triggering mobility LTM conditional handover corresponding to configuration layer 1 or layer 2 for the candidate cell; Alternatively, the handover execution condition of the corresponding LTM conditional handover is updated for the candidate cell.

8. The information transmission method according to claim 1, wherein: Also includes: Obtain the CU to which the candidate cell belongs, or, Obtain candidate cells corresponding to other CUs configured for the terminal device, or, Obtain all candidate cells configured for the terminal device.

9. The information transmission method according to claim 8, wherein: When configuring LTM conditional switching, the CU to which the candidate cell belongs is obtained; or, when configuring LTM conditional switching for the terminal device, the candidate cells corresponding to the other CUs are obtained.

10. An information transmission method, characterized in that: include: In response to switching to the first cell, accessing the first cell using a key corresponding to the first cell; The first cell is a candidate cell for the terminal device, and the first cell and the target cell belong to different centralized units respectively. The target cell is the cell that the terminal device last accessed before switching to the first cell; and before the terminal device accesses, the first cell has obtained the key corresponding to the first cell sent by the target cell.

11. An information transmission device, characterized in that: include: a sending unit, configured to send a key corresponding to the first cell to the first cell in response to the terminal device switching to the target cell; The first cell is a candidate cell of the terminal device, and the first cell and the target cell belong to different centralized units CU respectively.

12. An information transmission device, characterized in that: include: a processing unit, configured to, in response to switching to a first cell, access the first cell using a key corresponding to the first cell; The first cell is a candidate cell for the terminal device, and the first cell and the target cell belong to different centralized units respectively. The target cell is the cell that the terminal device last accessed before switching to the first cell; and before the terminal device accesses, the first cell has obtained the key corresponding to the first cell sent by the target cell.

13. A computer-readable storage medium, wherein the computer-readable storage medium is a non-volatile storage medium or a non-transient storage medium, and a computer program is stored thereon, wherein: When the computer program is executed by a processor, the steps of the information transmission method according to any one of claims 1 to 9 are executed; or, when the computer program is executed by a processor, the steps of the information transmission method according to claim 10 are executed.

14. An information transmission device comprising a memory and a processor, wherein the memory stores a computer program that can be run on the processor, characterized in that: When the processor runs the computer program, the steps of the information transmission method according to any one of claims 1 to 9 are executed; or, when the computer program is run by the processor, the steps of the information transmission method according to claim 10 are executed.

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