Secret key updating method, secret key communication method, terminal and network side equipment

Abstract

The invention discloses a secret key updating method, a communication method, a terminal and network side equipment, and belongs to the field of communication, and the secret key updating method comprises the following steps: under the condition that the terminal is switched to a target primary cell PCell, a primary secret key of a primary node MN where the target PCell is located is updated, and an auxiliary node SN is kept unchanged, determining an auxiliary secret key of the SN according to the primary secret key and an SN secret key counter, wherein the SN key counter is determined by at least one of the following modes: protocol agreement, source MN pre-configuration and switching command carrying.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of communication, and particularly relates to a key update method, a communication method, a terminal and a network side device. BACKGROUND

[0002] A terminal (User Equipment, UE) can communicate with two network nodes simultaneously through a dual connectivity (DC) technology. One network node is called a master node (MN), and the other network node is called a secondary node (SN). In each network node, a carrier aggregation (CA) technology is used, and a series of serving cells controlled by the network node, also called a cell group, can be configured for the UE. The cell group controlled by the MN is a master cell group (MCG), and the cell group controlled by the SN is a secondary cell group (SCG). Each cell group contains a special cell (SpCell) and a series of secondary cells (Scell). The special cell in the MCG is called a primary cell (PCell), and the special cell in the SCG is called a primary secondary cell (PSCell). In a cell group, the SpCell uses a primary carrier, and the other secondary cells use secondary carriers, and the resource scheduling in a cell group is performed by the SpCell.

[0003] In a communication system, a network side device can be split into a centralized unit (CU) and a distributed unit (DU), and the DU and the CU are connected through an F1 interface. One network side device can contain one CU and one or more DUs, and one DU contains one or more cells.

[0004] During movement of the UE, cell switching can be performed. In order to reduce the switching delay, an LTM (L1 / L2-Triggered mobility) mechanism can be used, for example, the DU uses L1 / L2 signaling to instruct the UE to switch to a suitable candidate cell according to the layer 1 measurement result reported by the UE. However, the current LTM mechanism only supports a cell switching process under the same CU, and the possibility of cross-CU cell switching is being discussed. Inter-CU switching can include the following scenarios:

[0005] 1) CU is acting as MN when DC is not configured;

[0006] 2) CU is acting as SN and MN is unchanged;

[0007] 3) CU is acting as MN and SN is unchanged or SN is released.

[0008] For the third inter-CU handover scenario (CU is acting as MN and SN is unchanged) described above, according to the related art, each time the master key is updated, the network side device needs to reconfigure the SN key counter to the UE through the radio resource control (RRC), so that in the continuous MN handover process, there is a problem of large RRC signaling overhead. SUMMARY

[0009] Embodiments of the present application provide a key update method, a communication method, a terminal and a network side device, which can solve the problem of large RRC signaling overhead in the continuous MN handover process in the related art.

[0010] In a first aspect, a key update method is provided, the method comprising:

[0011] In a case where a terminal updates a master key of a master node MN in which a target primary cell PCell is located after switching to the target PCell, and a secondary node SN remains unchanged, the secondary key of the SN is determined according to the master key and an SN key counter, wherein the SN key counter is determined by at least one of the following manners:

[0012] Protocol agreement;

[0013] Pre-configuration of a source MN;

[0014] Carried by a handover command.

[0015] In a second aspect, a communication method is provided, the method comprising:

[0016] A source master node MN sends first information to a terminal, wherein the first information comprises configuration information of a candidate cell, and the candidate cell is controlled by a candidate MN;

[0017] The source MN sends a handover command to the terminal to hand over to a target primary cell PCell, and the target PCell is one of the candidate cells.

[0018] The first information and / or the handover command carries an SN key counter, which is used by the terminal to determine the secondary key of the SN in the case that the terminal switches to the target PCell, the master key of the MN where the target PCell is located is updated, and the secondary node SN remains unchanged.

[0019] In a third aspect, a communication method is provided, which includes:

[0020] A source master node MN sends first information to a terminal, wherein the first information includes configuration information of candidate cells controlled by candidate MNs, and the first information carries a secondary node SN key counter, which is used by the terminal to determine the secondary key of the SN in the case that the terminal switches to a target primary cell PCell, the master key of the MN where the target PCell is located is updated, and the SN remains unchanged.

[0021] In a fourth aspect, a key updating apparatus is provided, which includes:

[0022] A processing module is configured to determine the secondary key of the SN according to the master key and an SN key counter in the case that the terminal switches to a target primary cell PCell, the master key of the master node MN where the target PCell is located is updated, and the secondary node SN remains unchanged, wherein the SN key counter is determined by at least one of the following manners:

[0023] Protocol agreement;

[0024] Pre-configuration of the source MN;

[0025] Carried by a handover command.

[0026] In a fifth aspect, a communication apparatus is provided, which includes:

[0027] A first sending module is configured to send first information to a terminal, wherein the first information includes configuration information of candidate cells controlled by candidate MNs;

[0028] A second sending module is configured to send a handover command to the terminal to switch to a target primary cell PCell, wherein the target PCell is one of the candidate cells;

[0029] The first information and / or the handover command carries an SN key counter, which is used by the terminal to determine the secondary key of the SN in the case that the terminal switches to the target PCell, the master key of the MN where the target PCell is located is updated, and the secondary node SN remains unchanged.

[0030] Sixthly, a communication device is provided, the device comprising:

[0031] The first sending module is used to send first information to the terminal, wherein the first information includes configuration information of candidate cells, the candidate cells are controlled by candidate MN, and the first information carries a secondary node SN key counter, the SN key counter is used by the terminal to determine the secondary key of SN when switching to target primary cell PCell, updating the primary key of the MN where the target PCell is located, and the SN remains unchanged.

[0032] In a seventh aspect, a key update apparatus is provided, the apparatus being configured to perform the steps of the method described in the first aspect.

[0033] In an eighth aspect, a terminal is provided, the terminal including a processor and a memory, the memory storing a program or instructions executable on the processor, the program or instructions, when executed by the processor, implementing the steps of the method as described in the first aspect.

[0034] A ninth aspect provides a terminal, including a processor and a communication interface, wherein the processor is configured to, when switching to a target primary cell PCell, updating the master key of the primary node MN where the target PCell is located, and keeping the secondary node SN unchanged, determine a secondary key of SN based on the master key and an SN key counter, wherein the SN key counter is determined by at least one of the following methods:

[0035] The agreement stipulates;

[0036] The source MN is pre-configured;

[0037] Switch command carrying.

[0038] In a tenth aspect, a network-side device is provided, the network-side device including a processor and a memory, the memory storing a program or instructions executable on the processor, the program or instructions, when executed by the processor, implementing the steps of the method as described in the second or third aspect.

[0039] Eleventhly, a network-side device is provided, including a processor and a communication interface, wherein the communication interface is used to send first information to a terminal, wherein the first information includes configuration information of a candidate cell, the candidate cell being controlled by a candidate MN; and to send a handover command to the terminal to a target primary cell PCell, the target PCell being one of the candidate cells; wherein the first information and / or the handover command carry an SN key counter, the SN key counter being used by the terminal to determine the secondary key of the SN when it switches to the target PCell, updates the primary key of the MN where the target PCell is located, and the secondary node SN remains unchanged.

[0040] In a twelfth aspect, a network-side device is provided, including a processor and a communication interface, wherein the communication interface is used to send first information to a terminal, wherein the first information includes configuration information of a candidate cell, the candidate cell is controlled by a candidate MN, and the first information carries a secondary node SN key counter, the SN key counter being used by the terminal to determine the secondary key of the SN when switching to a target primary cell PCell, updating the primary key of the MN where the target PCell is located, and the SN remains unchanged.

[0041] In a thirteenth aspect, a readable storage medium is provided, on which a program or instructions are stored, which, when executed by a processor, implement the steps of the method described in the first aspect, or the steps of the method described in the second aspect, or the steps of the method described in the third aspect.

[0042] In a fourteenth aspect, a wireless communication system is provided, comprising: a terminal and a network-side device, wherein the terminal is configured to perform the steps of the method described in the first aspect, and the network-side device is configured to perform the steps of the method described in the second or third aspect.

[0043] In a fifteenth aspect, a chip is provided, the chip including a processor and a communication interface coupled to the processor, the processor being configured to run a program or instructions to implement the method as described in the first aspect, or the method as described in the second aspect, or the method as described in the third aspect.

[0044] In a sixteenth aspect, a computer program / program product is provided, the computer program / program product being stored in a storage medium, the computer program / program product being executed by at least one processor to perform the steps of the method as described in the first aspect, the second aspect, or the third aspect.

[0045] In this embodiment, when the terminal switches to the target PCell, updates the master key of the primary node MN where the target PCell resides, and the secondary node SN remains unchanged, it determines the secondary key of the SN based on the master key and the SN key counter. The SN key counter can be determined by at least one of the following: protocol agreement, pre-configuration by the source MN, or carrying the SN key counter in the handover command. The terminal does not need the network-side device to reconfigure the SN key counter to the terminal via RRC every time the master key is updated. Therefore, during continuous MN handover, RRC signaling overhead can be reduced. Furthermore, the method of protocol agreement, pre-configuration by the source MN, or carrying the SN key counter in the handover command in this embodiment reduces the latency for the UE to obtain the SN key counter compared to the method of configuring the SN key counter via RRC, thus ensuring the continuity of the handover. Attached Figure Description

[0046] Figure 1 This is a block diagram of a wireless communication system applicable to embodiments of this application.

[0047] Figure 2 This is a schematic diagram of a dual-connection architecture provided in an embodiment of this application.

[0048] Figure 3 This is a flowchart illustrating a key update method proposed in one embodiment of this application.

[0049] Figure 4 This is a flowchart illustrating a key update method proposed in another embodiment of this application.

[0050] Figure 5 This is a flowchart illustrating a key update method proposed in another embodiment of this application.

[0051] Figure 6 This is a flowchart illustrating a communication method proposed in one embodiment of this application.

[0052] Figure 7 This is a flowchart illustrating a communication method proposed in another embodiment of this application.

[0053] Figure 8 This is a flowchart illustrating an application embodiment of the key update method proposed in this application.

[0054] Figure 9 This is a flowchart illustrating a second application embodiment of the key update method proposed in this application.

[0055] Figure 10 This is a flowchart illustrating a third application embodiment of the key update method proposed in this application.

[0056] Figure 11This is a flowchart illustrating a fourth application embodiment of the key update method proposed in this application.

[0057] Figure 12 This is a flowchart illustrating a fifth application embodiment of the key update method proposed in this application.

[0058] Figure 13 This is a schematic diagram of a key update device proposed in an embodiment of this application.

[0059] Figure 14 This is a schematic diagram of a key update device proposed in another embodiment of this application.

[0060] Figure 15 This is a schematic diagram of a key update device proposed in another embodiment of this application.

[0061] Figure 16 This is a schematic diagram of the structure of a communication device according to an embodiment of this application.

[0062] Figure 17 This is a schematic diagram of the structure of a communication device according to another embodiment of this application.

[0063] Figure 18 This is a schematic diagram of the structure of a communication device proposed in an embodiment of this application.

[0064] Figure 19 This is a schematic diagram of the structure of a terminal proposed in an embodiment of this application.

[0065] Figure 20 This is a schematic diagram of the structure of a network-side device proposed in an embodiment of this application. Detailed Implementation

[0066] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0067] The terms "first," "second," etc., used in this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first" and "second" are generally of the same class, not limited in number; for example, the first object can be one or more. Furthermore, "or" in this application indicates at least one of the connected objects. For example, the scope of protection for "A or B" covers at least three scenarios: Scenario 1: including A but not B; Scenario 2: including B but not A; Scenario 3: including both A and B. In addition, the terms "A and / or B," "at least one of A and B," and "at least one of A or B" also cover at least the above three scenarios. The character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0068] The term "instruction" in this application can be either a direct instruction (or explicit instruction) or an indirect instruction (or implicit instruction). A direct instruction can be understood as one in which the sender explicitly informs the receiver of specific information, the operation to be performed, or the requested result, etc., in the instruction sent. An indirect instruction can be understood as one in which the receiver determines the corresponding information based on the instruction sent by the sender, or makes a judgment and determines the operation to be performed or the requested result, etc., based on the judgment result.

[0069] It is worth noting that the technologies described in this application are not limited to Long Term Evolution (LTE) / LTE-Advanced (LTE-A) systems, but can also be used in other wireless communication systems, such as Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), Single-carrier Frequency-Division Multiple Access (SC-FDMA), or other systems. The terms "system" and "network" in this application are often used interchangeably, and the described technologies can be used with the systems and radio technologies mentioned above, as well as with other systems and radio technologies. The following description describes New Radio (NR) systems for illustrative purposes, and the term NR is used in most of the following description; however, these technologies can also be applied to systems other than NR systems, such as 6th generation (6G) radio systems. th Generation 6G communication system.

[0070] Figure 1This diagram illustrates a block diagram of a wireless communication system applicable to embodiments of this application. The wireless communication system includes a terminal 11 and a network-side device 12. The terminal 11 can be a mobile phone, tablet computer, laptop computer, notebook computer, personal digital assistant (PDA), handheld computer, netbook, ultra-mobile personal computer (UMPC), mobile internet device (MID), augmented reality (AR), virtual reality (VR) device, robot, wearable device, flight vehicle, vehicle user equipment (VUE), shipboard equipment, pedestrian user equipment (PUE), smart home devices (home appliances with wireless communication capabilities, such as refrigerators, televisions, washing machines, or furniture), game consoles, personal computers (PCs), ATMs, or self-service machines, etc. Wearable devices include: smartwatches, smart bracelets, smart headphones, smart glasses, smart jewelry (smart bracelets, smart chains, smart rings, smart necklaces, smart anklets, smart anklets, etc.), smart wristbands, smart clothing, etc. Among these, in-vehicle devices can also be referred to as in-vehicle terminals, in-vehicle controllers, in-vehicle modules, in-vehicle components, in-vehicle chips, or in-vehicle units, etc. It should be noted that the specific type of terminal 11 is not limited in this application embodiment. Network-side equipment 12 may include access network equipment or core network equipment, wherein access network equipment may also be referred to as Radio Access Network (RAN) equipment, radio access network function, or radio access network unit. Access network equipment may include base stations, Wireless Local Area Network (WLAN) access points (AS), or Wireless Fidelity (WiFi) nodes, etc.The term "base station" can be referred to as Node B (NB), Evolved Node B (eNB), Next Generation Node B (gNB), New Radio Node B (NR Node B), Access Point, Relay Base Station (RBS), Serving Base Station (SBS), Base Transceiver Station (BTS), Radio Base Station, Radio Transceiver, Basic Service Set (BSS), Extended Service Set (ESS), Home Node B (HNB), Home Evolved Node B, Transmit / Receive Point (TRP), or any other suitable term in the relevant field, as long as the same technical effect is achieved. The term "base station" is not limited to any specific technical terminology. It should be noted that this application embodiment only uses a base station in an NR system as an example for description and does not limit the specific type of base station.

[0071] Core network equipment, also known as core network nodes, core network functions, or core network elements, includes, but is not limited to, at least one of the following: Mobility Management Entity (MME), Access and Mobility Management Function (AMF), Session Management Function (SMF), User Plane Function (UPF), Policy Control Function (PCF), Policy and Charging Rules Function (PCRF), Edge Application Server Discovery Function (EASDF), Unified Data Management (UDM), Unified Data Repository (UDR), Home Subscriber Server (HSS), Centralized network configuration (CNC), Network Repository Function (NRF), Network Exposure Function (NEF), Local NEF (or L-NEF), and Binding Support Function. Support Functions (BSF), Application Functions (AF), Location Management Functions (LMF), Gateway Mobile Location Centres (GMLC), and Network Data Analytics Functions (NWDAF), etc. It should be noted that this application embodiment only uses core network equipment in the NR system as an example and does not limit the specific type of core network equipment. If the name of the core network equipment mentioned in this application embodiment changes in subsequent protocol versions (e.g., 6G), it will still be within the scope of protection of this application.

[0072] Optionally, the core network equipment can be implemented by one or more functional modules in a single device, or by multiple devices working together; this application does not specifically limit this. It is understood that the aforementioned functional modules can be network elements in hardware devices, software functional modules running on dedicated hardware, or virtualized functional modules instantiated on a platform (e.g., a cloud platform).

[0073] To better understand the technical solutions proposed in the embodiments of this application, the CU-DU structure will be illustrated below with examples. For instance... Figure 2 As shown, the 5G Radio Access Network (NG-RAN) 22 splits the 5G base station (the next generation Node B, gNB) 222 into a 5G base station centralized unit (gNB-CU) 2221 and a 5G base station distributed unit (gNB-DU) 2222, wherein gNB-CU 2221 and gNB-DU 2222 are connected via an F1 interface. Furthermore, as... Figure 2 As shown, gNB 222 is connected to another gNB 221 via the Xn-C interface, and gNB is connected to the 5G core network (5GCore, 5GC) 21 via the NG interface.

[0074] like Figure 2 As shown, in the CU-DU architecture, a gNB contains only one CU, and a gNB contains one or more DUs. A DU contains one or more cells.

[0075] When a UE performs a PCell handover between CUs, it needs to update the key between itself and the MN (hereinafter referred to as the master key); when a UE performs a PSCell handover between CUs, it needs to update the key between itself and the SN (hereinafter referred to as the secondary key); and even if the SN does not change, if the master key is updated, the secondary key also needs to be updated.

[0076] As described in the background technology, for the third type of CU handover scenario (CU acts as MN, SN remains unchanged), according to relevant technologies, each time the master key is updated, the network-side device needs to reconfigure the SN key counter to the UE through Radio Resource Control (RRC). Thus, during continuous MN handover, there will be problems such as large RRC signaling overhead and difficulty in ensuring handover continuity.

[0077] To address at least one of the aforementioned problems, this application proposes a key update method. The key update method provided by this application will be described in detail below with reference to the accompanying drawings and through some embodiments and application scenarios.

[0078] like Figure 3 As shown in the embodiments of this application, a key update method may include:

[0079] Step 301: When the terminal switches to the target primary cell PCell, updates the master key of the master node (MN) where the target PCell is located, and keeps the secondary node (SN) unchanged, it determines the secondary key of the SN based on the master key and the SN key counter (sk-Counter). The SN key counter can be determined by at least one of the following methods:

[0080] 1) As stipulated in the agreement;

[0081] 2) Source MN pre-configured;

[0082] 3) Switch command carrying.

[0083] This application addresses the third type of inter-CU handover scenario described in the background art (CU acts as MN, SN remains unchanged). In this scenario, if the master key changes, the terminal updates the secondary key based on the updated master key and the SN key counter (sk-Counter). When the terminal switches to a candidate cell, if that candidate cell has a secondary cell configured, it is considered that the terminal has performed a primary cell handover, or MN handover. Optionally, in some embodiments of this application, MN can also be replaced by MCG.

[0084] Terminal handover of the primary cell (Pcell) includes two scenarios: the first is a primary cell handover triggered by the source MN, such as when the source MN sends a handover command to indicate the handover; the second is a primary cell handover triggered by the terminal, such as when the terminal actively hands over when it determines that the handover conditions are met. The following sections will explain in detail how the terminal determines the SN key counter in each of these two scenarios.

[0085] like Figure 4 As shown, in the first case, before step 301, the key update method proposed in this application embodiment may further include:

[0086] Step 302: The terminal receives first information sent by the source MN, wherein the first information includes configuration information of the candidate cell, and the candidate cell is controlled by the candidate MN.

[0087] Among them, the source MN is the MN where the source primary cell (Source Pcell) is located, and the candidate MN is the MN where the candidate cell (Candidate Pcell) is located.

[0088] The first piece of information is used by the source MN to reconfigure the candidate cell configuration information to the terminal. Specifically, the first piece of information can be carried by Radio Resource Control (RRC) signaling.

[0089] Optionally, after receiving the first information, the terminal can also measure the candidate cell according to the configuration information of the candidate cell, obtain the measurement report (MR) of the candidate cell, and report the MR of the candidate cell to the source MN. The measurement report of the candidate cell is used by the source MN to determine the target PCell, and the target PCell is one of the candidate cells.

[0090] Step 303: The terminal receives a handover command sent by the source MN.

[0091] The switching command is used to instruct the terminal to switch to the target PCell.

[0092] Optionally, the handover command can be an LTM cell handover command MAC CE.

[0093] Optionally, the switching command may also carry a Next Hop Chaining Counter (NCC). Accordingly, before step 301, the key update method proposed in this application embodiment may further include:

[0094] The terminal updates the master key according to the NCC.

[0095] Specifically, the process of deriving the master key from the terminal may include:

[0096] -If the NCC value received by the terminal in the handover command is the same as the currently used K gNB / K eNB If the associated NCC is the same, the terminal will determine the current K. gNB / K eNB K is derived from the Physical Cell Identifier (PCI) and frequency level of the target primary cell. NG-RAN* .

[0097] -If the NCC value received by the terminal in the handover command is the same as the currently used K gNB / K eNBIf the associated NCCs are different, the terminal first synchronizes the NCC and the next hop (NH) until it matches the NCC indicated by the handover command; then the terminal obtains K based on the synchronized NH, the PCI of the target primary cell, and the frequency point vertical derivation. NG-RAN* .

[0098] Ultimately, the terminal uses K NG-RAN* K is used for communication with the target gNB / ng-eNB. gNB / K eNB Understandable, K NG-RAN* This is the updated master key.

[0099] Step 304: The terminal switches to the target PCell according to the handover command, and the target PCell is one of the candidate cells.

[0100] Furthermore, in the first case, the SN key counter is determined by at least one of the following methods:

[0101] The agreement stipulates;

[0102] The source MN is pre-configured;

[0103] Switch command carrying.

[0104] like Figure 5 As shown, in the second case, before step 301, the key update method proposed in this application embodiment may further include:

[0105] Step 302: The terminal receives first information sent by the source MN, wherein the first information includes configuration information of the candidate cell, and the candidate cell is controlled by the candidate MN.

[0106] Among them, the source MN is the MN where the source primary cell (Source Pcell) is located, and the candidate MN is the MN where the candidate cell (Candidate Pcell) is located.

[0107] The first piece of information is used by the source MN to reconfigure the candidate cell configuration information to the terminal. Specifically, the first piece of information can be carried by Radio Resource Control (RRC) signaling.

[0108] Step 305: When the terminal determines that the target PCell meets the handover conditions, it hands over to the target PCell, which is one of the candidate cells.

[0109] The SN key counter is determined by at least one of the following methods:

[0110] The agreement stipulates;

[0111] The source MN is pre-configured.

[0112] The network configures handover conditions associated with candidate cells for the terminal. After the terminal evaluates whether a candidate cell meets the handover conditions, it hands over to that candidate cell. For example, the handover conditions for A3 and A5 could be:

[0113] Event A3: The quality of the neighboring cell is one offset value higher than that of the serving cell;

[0114] Event A5: Service quality of the cell is below threshold 1;

[0115] The quality of the neighboring community is higher than the threshold of 2.

[0116] To avoid frequent handovers, a timeToTrigger parameter is configured in the base station for each handover condition. Handover will only be triggered when the L3 filtered signal quality of one or more candidate cells consistently meets the event entry conditions within the timeToTrigger time period.

[0117] Specifically, for the first scenario, in some embodiments, the SN key counter is carried by the switching command.

[0118] Accordingly, in step 301, determining the auxiliary key of the SN based on the master key and the SN key counter includes:

[0119] The secondary key of the SN is determined based on the master key and the SN key counter carried in the switching command.

[0120] In some embodiments, for the first or second scenario, the SN key counter is defined by a protocol, and the protocol specifies that the SN key counter has a first value, for example, sk-Counter = 0. Optionally, the protocol specifies that the SN key counter has a first value when a first condition is met, wherein the first condition includes at least one of the following:

[0121] The master key corresponding to the terminal has been changed, but the secondary cell group (SCG) has not been changed;

[0122] The master key corresponding to the terminal has been changed, and the source MN has not provided an SN key counter associated with the SCG;

[0123] The first message carries a secondary key change instruction;

[0124] The switching command carries a secondary key change instruction (only for the first case).

[0125] Accordingly, in step 301, determining the auxiliary key of the SN based on the master key and the SN key counter may include:

[0126] The secondary key of the SN is determined based on the master key and the SN key counter agreed upon in the protocol.

[0127] In some embodiments, in relation to the first or second scenario, the SN key counter is configured by the source MN using the first information, for example:

[0128] 1) The first information configuration associates all candidate cells with the same SN key counter. Correspondingly, in step 301, determining the secondary key of the SN based on the primary key and the SN key counter may include:

[0129] The secondary key of the SN is determined based on the master key and the SN key counters associated with all candidate cells.

[0130] 2) The first information configures a candidate cell or a list of candidate cells to be associated with an SN key counter. Accordingly, in step 301, determining the auxiliary key of the SN based on the master key and the SN key counter may include:

[0131] The auxiliary key of the SN is determined based on the master key and the SN key counter associated with the target PCell;

[0132] or,

[0133] The auxiliary key of the SN is determined based on the master key and the SN key counter associated with the candidate cell list where the target PCell is located.

[0134] 3) The first information configuration associates a candidate cell list with an NCC list, and an NCC list with an SN key counter list, and the elements in the associated NCC list and SN key counter list have a one-to-one correspondence. Accordingly, in step 301, determining the auxiliary key of the SN based on the master key and the SN key counter may include:

[0135] Determine the target NCC list associated with the candidate cell list where the target PCell is located;

[0136] Determine the SN key counter corresponding to the target PCell in the SN key counter list associated with the target NCC list;

[0137] The auxiliary key of the SN is determined based on the master key and the SN key counter corresponding to the target PCell.

[0138] Optionally, to facilitate handover between candidate cells in the same candidate cell list, the terminal performs Packet Data Convergence Protocol (PDCP) reconstruction and key (including master key and secondary key) update. When handover between candidate cells in different candidate cell lists, the terminal does not perform PDCP reconstruction and key update. Candidate cells in the same candidate cell list are configured with the same identifier so that the terminal can determine whether the two cells are in the same candidate cell list by whether the identifiers of the source primary cell and the target primary cell are the same.

[0139] Optionally, a key update method proposed in this application embodiment may further include:

[0140] The terminal stores the SN key counter configured by the source MN using the first information. The stored SN key counter is used to update the secondary key after the next PCell handover. This can further save downlink signaling resources and better ensure the continuity of primary cell handover.

[0141] This application proposes a key update method whereby a terminal, after switching to a target PCell and updating the master key of the primary node MN where the target PCell resides, while the secondary node SN remains unchanged, determines the secondary key of the SN based on the master key and the SN key counter. The SN key counter can be determined by at least one of the following: protocol agreement, pre-configuration by the source MN, or carrying the SN key counter in the handover command. The terminal does not need the network-side device to reconfigure the SN key counter to the terminal via RRC every time the master key is updated. Therefore, during continuous MN handover, RRC signaling overhead can be reduced. Furthermore, the method of protocol agreement, pre-configuration by the source MN, or carrying the SN key counter in the handover command, compared to the method of configuring the SN key counter via RRC, reduces the latency for the UE to obtain the SN key counter, ensuring the continuity of handover.

[0142] like Figure 6 As shown in the embodiments of this application, a communication method is also proposed, which may include:

[0143] Step 601: The source master node MN sends first information to the terminal, wherein the first information includes configuration information of the candidate cell, and the candidate cell is controlled by the candidate MN.

[0144] The first piece of information is used by the source MN to reconfigure the candidate cell configuration information to the terminal. Specifically, the first piece of information can be carried by Radio Resource Control (RRC) signaling.

[0145] Optionally, after sending the first information, the source MN can also receive the measurement report of the candidate cell reported by the terminal, and determine the target PCell based on the measurement report of the candidate cell. The target PCell is one of the candidate cells, wherein the measurement report of the candidate cell is obtained by the terminal based on the configuration information of the candidate cell.

[0146] Step 602: The source MN sends a handover command to the terminal to switch to the target primary cell PCell, where the target PCell is one of the candidate cells.

[0147] The first information and / or the switching command carries an SN key counter, which is used by the terminal to determine the secondary key of the SN when switching to the target PCell, updating the primary key of the MN where the target PCell is located, and keeping the secondary node SN unchanged.

[0148] The switching command is used to instruct the terminal to switch to the target PCell.

[0149] Optionally, the handover command can be an LTM cell handover command MAC CE.

[0150] Optionally, the switching command may also carry a Next Hop Chaining Counter (NCC), which is used by the terminal to update the master key.

[0151] In some embodiments, the switching command carries an SN key counter.

[0152] In other embodiments, the first information is configured with an SN key counter, for example:

[0153] 1) The first information configuration associates all candidate cells with the same SN key counter;

[0154] 2) The first information configures a candidate cell or a list of candidate cells to be associated with an SN key counter;

[0155] 3) The first information configuration associates a candidate cell list with an NCC list, and an NCC list with an SN key counter list, and the elements in the associated NCC list and SN key counter list have a one-to-one correspondence.

[0156] Optionally, to facilitate handover between candidate cells in the same candidate cell list, the terminal performs Packet Data Convergence Protocol (PDCP) reconstruction and key (including master key and secondary key) update. When handover between candidate cells in different candidate cell lists, the terminal does not perform PDCP reconstruction and key update. Candidate cells in the same candidate cell list are configured with the same identifier so that the terminal can determine whether the two cells are in the same candidate cell list by whether the identifiers of the source primary cell and the target primary cell are the same.

[0157] Optionally, a communication method proposed in this application embodiment may further include:

[0158] The source MN obtains the NCC list associated with the candidate cell list from the candidate MN.

[0159] The communication method proposed in this application embodiment can reduce RRC signaling overhead during continuous MN handover because the source MN can carry the SN key counter through the first information used to configure candidate cells or the handover command, instead of reconfiguring the SN key counter to the terminal every time the terminal updates the secondary key. In addition, the method of pre-configuring the source MN or carrying the SN key counter in the handover command in this application embodiment reduces the delay for the UE to obtain the SN key counter compared with the method of configuring the SN key counter by RRC, and can ensure the continuity of handover.

[0160] like Figure 7 As shown in the embodiments of this application, a communication method is also proposed, which may include:

[0161] Step 701: The source master node MN sends first information to the terminal. The first information includes configuration information of the candidate cell, which is controlled by the candidate MN. The first information also carries a secondary node SN key counter. The SN key counter is used by the terminal to determine the secondary key of the SN when it switches to the target master cell PCell, updates the master key of the MN where the target PCell is located, and the SN remains unchanged.

[0162] The first piece of information is used by the source MN to reconfigure the candidate cell configuration information to the terminal. Specifically, the first piece of information can be carried by Radio Resource Control (RRC) signaling.

[0163] Specifically, the first information is configured with an SN key counter, which may include:

[0164] 1) The first information configuration associates all candidate cells with the same SN key counter;

[0165] 2) The first information configures a candidate cell or a list of candidate cells to be associated with an SN key counter;

[0166] 3) The first information configuration associates a candidate cell list with an NCC list, and an NCC list with an SN key counter list, and the elements in the associated NCC list and SN key counter list have a one-to-one correspondence.

[0167] Optionally, to facilitate handover between candidate cells in the same candidate cell list, the terminal performs Packet Data Convergence Protocol (PDCP) reconstruction and key (including master key and secondary key) update. When handover between candidate cells in different candidate cell lists, the terminal does not perform PDCP reconstruction and key update. Candidate cells in the same candidate cell list are configured with the same identifier so that the terminal can determine whether the two cells are in the same candidate cell list by whether the identifiers of the source primary cell and the target primary cell are the same.

[0168] Optionally, a communication method proposed in this application embodiment may further include:

[0169] The source MN obtains the NCC list associated with the candidate cell list from the candidate MN.

[0170] The communication method proposed in this application embodiment can reduce RRC signaling overhead during continuous handover of the MN because the source MN can carry the SN key counter through the first information used to configure the candidate cell, instead of reconfiguring the SN key counter to the terminal every time the terminal updates the auxiliary key. In addition, the method of pre-configuring the SN key counter of the source MN in this application embodiment reduces the delay of the UE in obtaining the SN key counter compared with the method of configuring the SN key counter by RRC, and can ensure the continuity of handover.

[0171] The key update method proposed in this application will be described below through several specific embodiments.

[0172] Example 1: The protocol stipulates that the value of the SN key counter is 0 (sk-Counter = 0).

[0173] like Figure 8 As shown, the key update method proposed in this embodiment may include:

[0174] Step 801, switch preparation.

[0175] The source MN (S-MN) 82 obtains first information from the candidate MN (C-MN) 83, the first information including the configuration information of the candidate cell controlled by the C-MN 83; the source MN 82 sends the first information to the UE 81 via RRC reconfiguration. Here, the source MN 82 is the network node where the source PCell is located, and the candidate MN 83 is the network node where the candidate PCell is located.

[0176] Optionally, this embodiment may also include: step 802, whereby UE 81 reports a measurement report (MR) to S-MN 82.

[0177] Optionally, this embodiment may further include: step 803, whereby S-MN 82 sends a cell switch command to UE 81.

[0178] It should be noted that for Layer 3 handover (network-triggered handover via RRC indication) and LTM (network-triggered handover via MAC CE indication), the handover command is mandatory, therefore step 803 is mandatory; for conditional handover and conditional LTM, the handover command is not mandatory, therefore step 803 is not required.

[0179] Step 804: UE 81 switches to the candidate cell—the target primary cell—based on the received handover command or after UE 81 evaluates that the candidate cell meets the handover conditions. The configuration of the target primary cell is applied. If UE 81 updates the master key, the auxiliary key between UE 81 and SN 84 is calculated based on the updated master key and with sk-Counter=0 as the input as agreed in the protocol.

[0180] Specifically, the agreement stipulates at least one of the following:

[0181] When the master key changes but the SCG remains unchanged, the UE calculates the secondary key with sk-Counter=0 by default.

[0182] When the master key is changed and no sk-counter associated with the SCG key is provided, the UE calculates the secondary key with sk-counter=0 by default;

[0183] The first information of the RRC reconfiguration in step 801 carries a secondary key change indication, which implicitly indicates that the UE calculates the secondary key with sk-Counter=0 after the primary key is updated;

[0184] The handover command in step 804 carries a secondary key change instruction, which implicitly instructs the UE to calculate the secondary key with sk-Counter=0 after the primary key is updated.

[0185] Example 2: The source MN configures all candidate cells to be associated with the same SN key counter through the first information.

[0186] like Figure 9 As shown, the key update method proposed in this embodiment may include:

[0187] Step 901, switch preparation.

[0188] Specifically, S-MN 82 obtains first information from C-MN 83, which includes the configuration information of the candidate cells controlled by C-MN 83 and the SN key counter (sk-Counter); S-MN 82 sends the first information to UE81 through RRC reconfiguration.

[0189] Optionally, this embodiment may also include: step 902, whereby UE 81 reports a measurement report (MR) to S-MN 82.

[0190] Optionally, this embodiment may further include: step 903, whereby S-MN 82 sends a cell switch command to UE 81.

[0191] It should be noted that for Layer 3 handover (network-triggered handover via RRC indication) and LTM (network-triggered handover via MAC CE indication), the handover command is mandatory, therefore step 903 is mandatory; for conditional handover and conditional LTM, the handover command is not mandatory, therefore step 903 is not required.

[0192] Step 904: UE 81 switches to the candidate cell—the target primary cell—based on the received handover command or after UE 81 evaluates that the candidate cell meets the handover conditions. The configuration of the target primary cell is applied. If UE 81 updates the master key, the auxiliary key between UE 81 and SN 84 is calculated based on the updated master key and using the SN key counters (sk-Counter) associated with all candidate cells configured in the first information as input.

[0193] Example 3: The source MN configures a candidate cell or a list of candidate cells to be associated with an SN key counter through the first information.

[0194] like Figure 10As shown, the key update method proposed in this embodiment may include:

[0195] Step 1001, Switching Preparation.

[0196] Specifically, S-MN 82 obtains first information from C-MN 83, which includes configuration information of candidate cells controlled by C-MN 83 and SN key counters (sk-counters) associated with each candidate cell or each candidate cell list; S-MN 82 sends the first information to UE 81 through RRC reconfiguration.

[0197] Optionally, this embodiment may also include: step 1002, whereby UE 81 reports a measurement report (MR) to S-MN 82.

[0198] Optionally, this embodiment may also include: step 1003, whereby S-MN 82 sends a cell switch command to UE 81.

[0199] It should be noted that for Layer 3 handover (network-triggered handover via RRC indication) and LTM (network-triggered handover via MAC CE indication), the handover command is mandatory, therefore step 1003 is mandatory; for conditional handover and conditional LTM, the handover command is not mandatory, therefore step 1003 is not required.

[0200] Step 1004: UE 81 switches to the candidate cell—the target primary cell—based on the received handover command or after UE 81 evaluates that the candidate cell meets the handover conditions. The configuration of the target primary cell is applied. If UE 81 updates the master key, the auxiliary key between UE 81 and SN 84 is calculated based on the updated master key, using the SN key counter (sk-Counter) associated with the target primary cell or the candidate cell list where the target primary cell is located as configured in the first information as input.

[0201] Example 4: The source MN configures a candidate cell list to be associated with an NCC list through the first information, and an NCC list to be associated with an SN key counter list, and the elements in the associated NCC list and SN key counter list have a one-to-one correspondence.

[0202] like Figure 11 As shown, the key update method proposed in this embodiment may include:

[0203] Step 1101, switch preparation.

[0204] Specifically, S-MN 82 obtains first information from C-MN 83, wherein the first information includes configuration information of candidate cells controlled by C-MN 83, and further includes: an NCC list associated with each candidate cell list, and an SN key counter list associated with each NCC list. S-MN 82 sends the first information to UE 81 via RRC reconfiguration.

[0205] Optionally, candidate cells in the same candidate cell list have the same identifier.

[0206] Optionally, S-MN 82 obtains the sk-Counter list associated with each candidate cell list (or the NCC list associated with each candidate cell list) from C-MN 83.

[0207] Optionally, this embodiment may also include: step 1102, whereby UE 81 reports a measurement report (MR) to S-MN 82.

[0208] Optionally, this embodiment may also include: step 1103, S-MN 82 sends a cell switch command to UE 81.

[0209] It should be noted that for Layer 3 handover (network-triggered handover via RRC indication) and LTM (network-triggered handover via MAC CE indication), the handover command is mandatory, therefore step 1103 is mandatory; for conditional handover and conditional LTM, the handover command is not mandatory, therefore step 1103 is not required.

[0210] Step 1104: UE 81 switches to the candidate cell—the target primary cell—based on the received handover command or after UE 81 evaluates that the candidate cell meets the handover conditions. The configuration of the target primary cell is applied. If UE 81 updates the master key, the auxiliary key between UE 81 and SN 84 is calculated based on the updated master key and the SN key counter (sk-Counter) associated with the NCC of the target primary cell configured in the first information is used as input.

[0211] Example 5: The handover command carries the SN key counter (sk-Counter)

[0212] like Figure 12 As shown, the key update method proposed in this embodiment may include:

[0213] Step 1201, switch preparation.

[0214] Specifically, S-MN 82 obtains first information from C-MN 83, wherein the first information includes configuration information of candidate cells controlled by C-MN 83. S-MN 82 can send the first information to UE 81 via RRC reconfiguration.

[0215] Optionally, this embodiment may also include: step 1202, whereby UE 81 reports a measurement report (MR) to S-MN 82.

[0216] Step 1203: S-MN 82 sends a cell switch command to UE 81.

[0217] The handover command is an LTM Cell Switch Command MAC CE, and the handover command carries an SN key counter (sk-Counter).

[0218] Step 1204: UE 81 switches to the candidate cell - target primary cell according to the received handover command, applies the target primary cell configuration, and if UE 81 updates the master key according to the NCC carried in the handover name, then the auxiliary key between UE 81 and SN 84 is calculated according to the updated master key and the SN key counter (sk-Counter) carried in the handover command as input.

[0219] The key update method provided in this application embodiment, in the third type of CU handover scenario (CU acts as MN, SN remains unchanged) described in the background art, can avoid the signaling overhead and handover discontinuity caused by sk-Counter reconfiguration during continuous CU PCell handover.

[0220] This application provides a key update method, the execution subject of which can be a virtual device. This application uses a virtual device executing the key update method as an example to illustrate the key update device provided in this application.

[0221] like Figure 13 As shown, one embodiment of this application proposes a key update device 1400, which can be used in a terminal. The device 1300 may include a processing module 1301.

[0222] Processing module 1301 is configured to, when switching to a target primary cell PCell, updating the master key of the master node (MN) where the target PCell resides, and keeping the secondary node (SN) unchanged, determine the secondary key of the SN based on the master key and the SN key counter (sk-Counter), wherein the SN key counter is determined by at least one of the following methods:

[0223] The agreement stipulates;

[0224] The source MN is pre-configured;

[0225] Switch command carrying.

[0226] like Figure 14 As shown, in the first case, the key update device 1300 proposed in this application embodiment may further include:

[0227] The first receiving module 1302 is configured to receive first information sent by the source MN before determining the auxiliary key of the SN based on the master key and the SN key counter, wherein the first information includes configuration information of the candidate cell, and the candidate cell is controlled by the candidate MN.

[0228] Among them, the source MN is the MN where the source primary cell (Source Pcell) is located, and the candidate MN is the MN where the candidate cell (Candidate Pcell) is located.

[0229] The first piece of information is used by the source MN to reconfigure the candidate cell configuration information to the terminal. Specifically, the first piece of information can be carried by Radio Resource Control (RRC) signaling.

[0230] Optionally, after receiving the first information, the device 1300 can also measure the candidate cell according to the configuration information of the candidate cell, obtain the measurement report (MR) of the candidate cell, and report the MR of the candidate cell to the source MN. The measurement report of the candidate cell is used by the source MN to determine the target PCell, and the target PCell is one of the candidate cells.

[0231] The second receiving module 1303 is used to receive the switching command sent by the source MN.

[0232] The switching command is used to instruct the terminal to switch to the target PCell.

[0233] Optionally, the handover command can be an LTM cell handover command MAC CE.

[0234] Optionally, the switching command may also carry a Next Hop Chaining Counter (NCC). Accordingly, the key update method proposed in this application embodiment may further include: a master key update module, used to update the master key according to the NCC before determining the secondary key of the SN according to the master key and the SN key counter.

[0235] The first handover module 1304 is used to switch to the target PCell according to the handover command, wherein the target PCell is one of the candidate cells.

[0236] Furthermore, in the first case, the SN key counter is determined by at least one of the following methods:

[0237] The agreement stipulates;

[0238] The source MN is pre-configured;

[0239] Switch command carrying.

[0240] like Figure 15 As shown, in the second case, the key update device 1300 proposed in this application embodiment may further include:

[0241] The first receiving module 1302 is used to receive first information sent by the source MN, wherein the first information includes configuration information of the candidate cell, and the candidate cell is controlled by the candidate MN.

[0242] Among them, the source MN is the MN where the source primary cell (Source Pcell) is located, and the candidate MN is the MN where the candidate cell (Candidate Pcell) is located.

[0243] The first piece of information is used by the source MN to reconfigure the candidate cell configuration information to the terminal. Specifically, the first piece of information can be carried by Radio Resource Control (RRC) signaling.

[0244] The second handover module 1305 is used to hand over to the target PCell when it is determined that the target PCell meets the handover conditions, wherein the target PCell is one of the candidate cells;

[0245] The SN key counter is determined by at least one of the following methods:

[0246] The agreement stipulates;

[0247] The source MN is pre-configured.

[0248] Specifically, regarding the first scenario, in some embodiments, the SN key counter is carried by the switching command. Accordingly, the processing module 1301 can be specifically used to: determine the secondary key of the SN based on the master key and the SN key counter carried in the switching command.

[0249] In some embodiments, for the first or second scenario, the SN key counter is defined by a protocol, and the protocol specifies that the SN key counter has a first value, for example, sk-Counter = 0. Optionally, the protocol specifies that the SN key counter has a first value when a first condition is met, wherein the first condition includes at least one of the following:

[0250] The master key corresponding to the terminal has been changed, but the SCG has not been changed;

[0251] The master key corresponding to the terminal has been changed, and the source MN has not provided an SN key counter associated with the SCG;

[0252] The first message carries a secondary key change instruction;

[0253] The switching command carries a secondary key change instruction (only for the first case).

[0254] Accordingly, the processing module 1301 can be specifically used to: determine the auxiliary key of the SN based on the master key and the SN key counter agreed upon in the protocol.

[0255] In some embodiments, in relation to the first or second scenario, the SN key counter is configured by the source MN using the first information, for example:

[0256] 1) The first information configuration associates all candidate cells with the same SN key counter. Accordingly, in step 301, the processing module 1301 can be specifically used to: determine the auxiliary key of the SN based on the master key and the SN key counters associated with all candidate cells.

[0257] 2) The first information configures a candidate cell or a list of candidate cells to be associated with an SN key counter. Accordingly, the processing module 1301 can be specifically used to: determine the auxiliary key of the SN based on the SN key counter associated with the master key and the target PCell; or, determine the auxiliary key of the SN based on the SN key counter associated with the list of candidate cells where the target PCell is located.

[0258] 3) The first information configures a candidate cell list associated with an NCC list, and an NCC list associated with an SN key counter list, with a one-to-one correspondence between the elements in the associated NCC list and the SN key counter list. Accordingly, the processing module 1301 can specifically be used for:

[0259] Determine the target NCC list associated with the candidate cell list where the target PCell is located;

[0260] Determine the SN key counter corresponding to the target PCell in the SN key counter list associated with the target NCC list;

[0261] The auxiliary key of the SN is determined based on the master key and the SN key counter corresponding to the target PCell.

[0262] Optionally, to facilitate handover between candidate cells in the same candidate cell list, the terminal performs Packet Data Convergence Protocol (PDCP) reconstruction and key (including master key and secondary key) update. When handover between candidate cells in different candidate cell lists, the terminal does not perform PDCP reconstruction and key update. Candidate cells in the same candidate cell list are configured with the same identifier so that the terminal can determine whether the two cells are in the same candidate cell list by whether the identifiers of the source primary cell and the target primary cell are the same.

[0263] Optionally, the key update device 1300 proposed in this application embodiment may further include: a key counter storage module, used to store the SN key counter configured by the source MN through the first information, wherein the stored SN key counter is used to update the auxiliary key after the next handover of PCell, which can further save downlink signaling resources and better ensure the continuity of primary cell handover.

[0264] This application provides a key update device 1300 that, when a terminal switches to a target PCell and updates the master key of the primary node MN where the target PCell resides, while the secondary node SN remains unchanged, determines the secondary key of the SN based on the master key and the SN key counter. The SN key counter can be determined by at least one of the following: protocol agreement, pre-configuration by the source MN, or carrying the SN key counter in the handover command. The terminal does not need to have the network-side device reconfigure the SN key counter to the terminal via RRC every time the master key is updated. Therefore, during continuous MN handover, RRC signaling overhead can be reduced. Furthermore, the method of protocol agreement, pre-configuration by the source MN, or carrying the SN key counter in the handover command, compared to the method of configuring the SN key counter via RRC, reduces the latency for the UE to obtain the SN key counter, ensuring the continuity of the handover.

[0265] like Figure 16 As shown in the embodiments of this application, a communication device 1600 is also proposed, which can be applied to a source MN. The device 1600 may include:

[0266] The first sending module 1601 is used to send first information to the terminal, wherein the first information includes configuration information of candidate cells, and the candidate cells are controlled by candidate MN.

[0267] The first piece of information is used to reconfigure the candidate cell configuration information to the terminal. Specifically, the first piece of information can be carried by Radio Resource Control (RRC) signaling.

[0268] Optionally, after sending the first information, the device 1600 may also receive the measurement report of the candidate cell reported by the terminal, and determine the target PCell based on the measurement report of the candidate cell. The target PCell is one of the candidate cells, wherein the measurement report of the candidate cell is obtained by the terminal based on the configuration information of the candidate cell.

[0269] The second sending module 1602 is used to send a handover command to the terminal to switch to the target primary cell PCell, wherein the target PCell is one of the candidate cells.

[0270] The first information and / or the switching command carries an SN key counter, which is used by the terminal to determine the secondary key of the SN when switching to the target PCell, updating the primary key of the MN where the target PCell is located, and keeping the secondary node SN unchanged.

[0271] The switching command is used to instruct the terminal to switch to the target PCell.

[0272] Optionally, the handover command can be an LTM cell handover command MAC CE.

[0273] Optionally, the switching command may also carry a Next Hop Chaining Counter (NCC), which is used by the terminal to update the master key.

[0274] In some embodiments, the switching command carries an SN key counter.

[0275] In other embodiments, the first information is configured with an SN key counter, for example:

[0276] 1) The first information configuration associates all candidate cells with the same SN key counter;

[0277] 2) The first information configures a candidate cell or a list of candidate cells to be associated with an SN key counter;

[0278] 3) The first information configuration associates a candidate cell list with an NCC list, and an NCC list with an SN key counter list, and the elements in the associated NCC list and SN key counter list have a one-to-one correspondence.

[0279] Optionally, to facilitate handover between candidate cells in the same candidate cell list, the terminal performs Packet Data Convergence Protocol (PDCP) reconstruction and key (including master key and secondary key) update. When handover between candidate cells in different candidate cell lists, the terminal does not perform PDCP reconstruction and key update. Candidate cells in the same candidate cell list are configured with the same identifier so that the terminal can determine whether the two cells are in the same candidate cell list by whether the identifiers of the source primary cell and the target primary cell are the same.

[0280] Optionally, the communication device 1600 proposed in this application embodiment may further include: an NCC list acquisition module, used to acquire the NCC list associated with the candidate cell list from the candidate MN.

[0281] The communication device 1600 proposed in this application embodiment can reduce RRC signaling overhead during continuous MN handover by carrying the SN key counter in the first information or handover command used to configure the candidate cell, instead of reconfiguring the SN key counter to the terminal every time the secondary key is updated. In addition, the method of pre-configuring the source MN or carrying the SN key counter in the handover command in this application embodiment reduces the delay of the UE in obtaining the SN key counter compared with the method of configuring the SN key counter by RRC, and can ensure the continuity of handover.

[0282] like Figure 17 As shown in the embodiments of this application, a communication device 1700 is also proposed, which can be applied to a source MN. The device 1700 may include:

[0283] The first sending module 1701 is used to send first information to the terminal, wherein the first information includes configuration information of candidate cells, the candidate cells are controlled by candidate MN, and the first information carries a secondary node SN key counter, the SN key counter is used by the terminal to determine the secondary key of SN when switching to target primary cell PCell, updating the primary key of the MN where the target PCell is located, and the SN remains unchanged.

[0284] The first piece of information is used by the source MN to reconfigure the candidate cell configuration information to the terminal. Specifically, the first piece of information can be carried by Radio Resource Control (RRC) signaling.

[0285] Specifically, the first information is configured with an SN key counter, which may include:

[0286] 1) The first information configuration associates all candidate cells with the same SN key counter;

[0287] 2) The first information configures a candidate cell or a list of candidate cells to be associated with an SN key counter;

[0288] 3) The first information configuration associates a candidate cell list with an NCC list, and an NCC list with an SN key counter list, and the elements in the associated NCC list and SN key counter list have a one-to-one correspondence.

[0289] Optionally, to facilitate handover between candidate cells in the same candidate cell list, the terminal performs Packet Data Convergence Protocol (PDCP) reconstruction and key (including master key and secondary key) update. When handover between candidate cells in different candidate cell lists, the terminal does not perform PDCP reconstruction and key update. Candidate cells in the same candidate cell list are configured with the same identifier so that the terminal can determine whether the two cells are in the same candidate cell list by whether the identifiers of the source primary cell and the target primary cell are the same.

[0290] Optionally, the communication device 1700 proposed in this application embodiment may further include: an NCC list acquisition module, used to acquire the NCC list associated with the candidate cell list from the candidate MN.

[0291] The communication device 1700 proposed in this application embodiment can reduce RRC signaling overhead during continuous handover of the MN by carrying the SN key counter through the first information used to configure the candidate cell, instead of reconfiguring the SN key counter to the terminal every time the terminal updates the secondary key. In addition, the method of pre-configuring the SN key counter of the source MN in this application embodiment reduces the delay of the UE in obtaining the SN key counter compared with the method of configuring the SN key counter by RRC, and can ensure the continuity of handover.

[0292] The key update device 1300 provided in this application embodiment can achieve... Figure 3 The various processes implemented in the method embodiments of this application achieve the same technical effect, and will not be described again here to avoid repetition. The communication device 1600 provided in the embodiments of this application can realize Figure 6 The various processes implemented in the method embodiments of this application achieve the same technical effect, and will not be described again here to avoid repetition. The communication device 1700 provided in the embodiments of this application can realize Figure 7 The various processes implemented in the method embodiments achieve the same technical effect, and will not be described again here to avoid repetition.

[0293] like Figure 18As shown in the illustration, this application also provides a communication device 1800, including a processor 1801 and a memory 1802. The memory 1802 stores a program or instructions that can run on the processor 1801. For example, when the communication device 1800 is a terminal, the program or instructions executed by the processor 1801 implement the various steps of the above-described key update method embodiment and achieve the same technical effect. When the communication device 1800 is a network-side device, the program or instructions executed by the processor 1801 implement the various steps of the above-described communication method embodiment and achieve the same technical effect. To avoid repetition, further details are omitted here.

[0294] This application embodiment also provides a terminal, including a processor and a communication interface, wherein the communication interface is coupled to the processor, and the processor is used to run programs or instructions to implement, for example... Figure 3 The steps in the method embodiment shown are illustrated. This terminal embodiment corresponds to the above-described terminal-side method embodiment. All implementation processes and methods of the above-described method embodiments can be applied to this terminal embodiment and achieve the same technical effect. The terminal can be... Figure 13 The key update device shown. Specifically, Figure 19 A schematic diagram of the hardware structure of a terminal to implement an embodiment of this application.

[0295] The terminal 1900 includes, but is not limited to, at least some of the following components: radio frequency unit 1901, network module 1902, audio output unit 1903, input unit 1904, sensor 1905, display unit 1906, user input unit 1907, interface unit 1908, memory 1909, and processor 1910.

[0296] Those skilled in the art will understand that the terminal 1900 may also include a power supply (such as a battery) for supplying power to various components. The power supply may be logically connected to the processor 1910 through a power management system, thereby enabling functions such as managing charging, discharging, and power consumption through the power management system. Figure 19 The terminal structure shown does not constitute a limitation on the terminal. The terminal may include more or fewer components than shown, or combine certain components, or have different component arrangements, which will not be elaborated here.

[0297] It should be understood that, in this embodiment, the input unit 1904 may include a graphics processor 19041 and a microphone 19042. The graphics processor 19041 processes image data of still images or videos obtained by an image capture device (such as a camera) in video capture mode or image capture mode. The display unit 1906 may include a display panel 19061, which may be configured in the form of a liquid crystal display, an organic light-emitting diode, or the like. The user input unit 1907 includes at least one of a touch panel 19071 and other input devices 19072. The touch panel 19071 is also called a touch screen. The touch panel 19071 may include a touch detection device and a touch controller. Other input devices 19072 may include, but are not limited to, a physical keyboard, function keys (such as volume control buttons, power buttons, etc.), a trackball, a mouse, and a joystick, which will not be described in detail here.

[0298] In this embodiment, after receiving downlink data from the network-side device, the radio frequency unit 1901 can transmit it to the processor 1910 for processing; in addition, the radio frequency unit 1901 can send uplink data to the network-side device. Typically, the radio frequency unit 1901 includes, but is not limited to, antennas, amplifiers, transceivers, couplers, low-noise amplifiers, duplexers, etc.

[0299] The memory 1909 can be used to store software programs or instructions, as well as various data. The memory 1909 may primarily include a first storage area for storing programs or instructions and a second storage area for storing data. The first storage area may store the operating system, application programs or instructions required for at least one function (such as sound playback, image playback, etc.). Furthermore, the memory 1909 may include volatile memory or non-volatile memory. The non-volatile memory may 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. Volatile memory can be random access memory (RAM), static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDRSDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM), and direct memory bus RAM (DRRAM). The memory 1909 in the embodiments of this application includes, but is not limited to, these and any other suitable types of memory.

[0300] Processor 1910 may include one or more processing units; optionally, processor 1910 integrates an application processor and a modem processor, wherein the application processor mainly handles operations involving the operating system, user interface, and applications, and the modem processor mainly handles wireless communication signals, such as a baseband processor. It is understood that the aforementioned modem processor may also not be integrated into processor 1910.

[0301] The processor 1910 is configured to, when switching to a target primary cell PCell, updating the master key of the primary node MN where the target PCell resides, and keeping the secondary node SN unchanged, determine the secondary key of the SN based on the master key and the SN key counter, wherein the SN key counter is determined by at least one of the following methods:

[0302] The agreement stipulates;

[0303] The source MN is pre-configured;

[0304] Switch command carrying.

[0305] This application proposes a terminal that, when switching to a target PCell and updating the master key of the primary node MN where the target PCell resides, while the secondary node SN remains unchanged, determines the secondary key of the SN based on the master key and the SN key counter. The SN key counter can be determined by at least one of the following: protocol agreement, pre-configuration by the source MN, or carrying the SN key counter in the handover command. The terminal does not need the network-side device to reconfigure the SN key counter to the terminal via RRC every time the master key is updated. Therefore, during continuous MN handover, RRC signaling overhead can be reduced. Furthermore, the method of protocol agreement, pre-configuration by the source MN, or carrying the SN key counter in the handover command, compared to the method of configuring the SN key counter via RRC, reduces the latency for the UE to obtain the SN key counter, ensuring the continuity of the handover.

[0306] It is understood that the implementation process of each implementation method mentioned in this embodiment can refer to the relevant description of the method embodiment and achieve the same or corresponding technical effect. To avoid repetition, it will not be described again here.

[0307] This application embodiment also provides a network-side device, including a processor and a communication interface, wherein the communication interface is coupled to the processor, and the processor is used to run programs or instructions to implement, for example... Figure 6 or Figure 7 The steps of the method embodiment shown are illustrated. This network-side device embodiment corresponds to the above-described network-side device method embodiment. All implementation processes and methods of the above-described method embodiments can be applied to this network-side device embodiment and can achieve the same technical effect.

[0308] Specifically, embodiments of this application also provide a network-side device, which can be... Figure 16 or Figure 17 The communication device shown. (For example) Figure 20 As shown, the network-side device 2000 includes: an antenna 2001, a radio frequency (RF) device 2002, a baseband device 2003, a processor 2004, and a memory 2005. The antenna 2001 is connected to the RF device 2002. In the uplink direction, the RF device 2002 receives information through the antenna 2001 and transmits the received information to the baseband device 2003 for processing. In the downlink direction, the baseband device 2003 processes the information to be transmitted and sends it to the RF device 2002. The RF device 2002 processes the received information and transmits it through the antenna 2001.

[0309] The method executed by the network-side device in the above embodiments can be implemented in the baseband device 2003, which includes a baseband processor.

[0310] The baseband device 2003 may, for example, include at least one baseband board on which multiple chips are disposed, such as... Figure 20 As shown, one of the chips is, for example, a baseband processor, which is connected to the memory 2005 via a bus interface to call the program in the memory 2005 and execute the network-side device operations shown in the above method embodiment.

[0311] The network-side device may also include a network interface 2006, such as a Common Public Radio Interface (CPRI).

[0312] Specifically, the network-side device 2000 in this application embodiment further includes: instructions or programs stored in memory 2005 and executable on processor 2004, wherein processor 2004 calls the instructions or programs in memory 2005 to execute. Figure 16 or Figure 17 The methods executed by each module shown achieve the same technical effect, and to avoid repetition, they will not be described in detail here.

[0313] This application also provides a readable storage medium storing a program or instructions. When the program or instructions are executed by a processor, they implement the various processes of the above-described key update method or the above-described communication method embodiments and achieve the same technical effect. To avoid repetition, they will not be described again here.

[0314] The processor mentioned above is the processor in the terminal described in the above embodiments. The readable storage medium includes computer-readable storage media, such as computer read-only memory (ROM), random access memory (RAM), magnetic disk, or optical disk. In some examples, the readable storage medium may be a non-transient readable storage medium.

[0315] This application embodiment also provides a chip, which includes a processor and a communication interface. The communication interface is coupled to the processor. The processor is used to run programs or instructions to implement the various processes of the above-described key update method or the above-described communication method embodiment, and can achieve the same technical effect. To avoid repetition, it will not be described again here.

[0316] It should be understood that the chip mentioned in the embodiments of this application may also be referred to as a system-on-a-chip, system chip, chip system, or system-on-a-chip, etc.

[0317] This application also provides a computer program / program product, which is stored in a storage medium and executed by at least one processor to implement the various processes of the above-described key update method embodiments, and can achieve the same technical effect. To avoid repetition, it will not be described again here.

[0318] This application also provides a communication system, including: a terminal and a network-side device, wherein the terminal can be used to perform... Figure 2 The network-side device can be used to execute the steps of the key update method described above. Figure 13 The steps of the key update method described above.

[0319] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element. Furthermore, it should be noted that the scope of the methods and apparatuses in the embodiments of this application is not limited to performing functions in the order shown or discussed, but may also include performing functions substantially simultaneously or in the reverse order, depending on the functions involved. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Additionally, features described with reference to certain examples may be combined in other examples.

[0320] From the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of computer software products plus necessary general-purpose hardware platforms, and of course, they can also be implemented by hardware. The computer software product is stored in a storage medium (such as ROM, RAM, magnetic disk, optical disk, etc.) and includes several instructions to cause the terminal or network-side device to execute the methods described in the various embodiments of this application.

[0321] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other implementations under the guidance of this application without departing from the spirit and scope of the claims. All of these implementations are within the protection scope of this application.

Claims

1. A key update method, characterized in that, The method includes: When a terminal switches to a target primary cell PCell, updates the master key of the primary node MN where the target PCell resides, and keeps the secondary node SN unchanged, it determines the secondary key of the SN based on the master key and the SN key counter, wherein the SN key counter is determined by at least one of the following methods: The agreement stipulates; The source MN is pre-configured; Switch command carrying.

2. The method according to claim 1, characterized in that, Before determining the secondary key of the SN, the method further includes: The terminal receives first information sent by the source MN, wherein the first information includes configuration information of candidate cells, and the candidate cells are controlled by the candidate MN; The terminal receives the switching command sent by the source MN; The terminal switches to the target PCell according to the handover command, and the target PCell is one of the candidate cells.

3. The method according to claim 2, characterized in that, The switching command carries a next-hop link counter (NCC). Before determining the secondary key for the serial number (SN), the method further includes: The terminal updates the master key according to the NCC.

4. The method according to claim 2 or 3, characterized in that, The handover command is the LTM cell handover command MACCE.

5. The method according to any one of claims 2-4, characterized in that, The SN key counter is carried by the switching command.

6. The method according to claim 1, characterized in that, Before determining the secondary key of the SN, the method further includes: The terminal receives first information sent by the source MN, wherein the first information includes configuration information of candidate cells, and the candidate cells are controlled by the candidate MN; When the terminal determines that the target PCell meets the handover conditions, it hands over to the target PCell, which is one of the candidate cells. The SN key counter is determined by at least one of the following methods: The agreement stipulates; The source MN is pre-configured.

7. The method according to any one of claims 2-4 and 6, characterized in that, The SN key counter is defined by the protocol, and the protocol stipulates that the SN key counter has a first value.

8. The method according to claim 7, characterized in that, The agreement stipulates that the SN key counter will have a first value if a first condition is met, wherein the first condition includes at least one of the following: The master key corresponding to the terminal has been changed, but the secondary cell group (SCG) has not been changed. The master key corresponding to the terminal has been changed, and the source MN has not provided an SN key counter associated with the SCG; The first message carries a secondary key change instruction; The switching command includes a secondary key change instruction.

9. The method according to any one of claims 2-4 and 6, characterized in that, The SN key counter is configured by the source MN using the first information.

10. The method according to claim 9, characterized in that, The first information configuration associates all candidate cells with the same SN key counter, wherein determining the secondary key of the SN based on the primary key and the SN key counter includes: The secondary key of the SN is determined based on the master key and the SN key counters associated with all candidate cells.

11. The method according to claim 9, characterized in that, The first information configures a candidate cell or a list of candidate cells to be associated with an SN key counter, wherein determining the secondary key of the SN based on the primary key and the SN key counter includes: The auxiliary key of the SN is determined based on the master key and the SN key counter associated with the target PCell; or, The auxiliary key of the SN is determined based on the master key and the SN key counter associated with the candidate cell list where the target PCell is located.

12. The method according to claim 9, characterized in that, The first information configuration associates a candidate cell list with an NCC list, and an NCC list with an SN key counter list, with a one-to-one correspondence between elements in the associated NCC list and SN key counter list. The step of determining the secondary key of the SN based on the primary key and the SN key counter includes: Determine the target NCC list associated with the candidate cell list where the target PCell is located; Determine the SN key counter corresponding to the target PCell in the SN key counter list associated with the target NCC list; The auxiliary key of the SN is determined based on the master key and the SN key counter corresponding to the target PCell.

13. The method according to claim 11 or 12, characterized in that, Candidate cells in the same candidate cell list are configured with the same identifier.

14. The method according to any one of claims 9-13, characterized in that, The method further includes: The terminal stores the SN key counter configured by the source MN using the first information, wherein the stored SN key counter is used to update the secondary key after the next PCell switch.

15. A communication method, characterized in that, The method includes: The source master node (MN) sends first information to the terminal, wherein the first information includes configuration information of candidate cells, and the candidate cells are controlled by the candidate MN; The source MN sends a handover command to the terminal to switch to the target primary cell PCell, where the target PCell is one of the candidate cells; The first information and / or the switching command carries an SN key counter, which is used by the terminal to determine the secondary key of the SN when switching to the target PCell, updating the primary key of the MN where the target PCell is located, and keeping the secondary node SN unchanged.

16. The method according to claim 15, characterized in that, The switching command also carries a next-hop link counter (NCC), which is used by the terminal to update the master key.

17. The method according to claim 15 or 16, characterized in that, The handover command is the LTM cell handover command MAC CE.

18. The method according to any one of claims 15 to 17, characterized in that, The SN key counter is configured by the source MN using the first information.

19. The method according to claim 18, characterized in that, The first information configuration associates all candidate cells with the same SN key counter.

20. The method according to claim 18, characterized in that, The first information configures a candidate cell or a list of candidate cells to be associated with an SN key counter.

21. The method according to claim 18, characterized in that, The first information configuration associates a candidate cell list with an NCC list, and an NCC list with an SN key counter list, and the elements in the associated NCC list and SN key counter list have a one-to-one correspondence.

22. The method according to claim 20 or 21, characterized in that, Candidate cells in the same candidate cell list are configured with the same identifier.

23. The method according to any one of claims 20-22, characterized in that, The method further includes: The source MN obtains the NCC list associated with the candidate cell list from the candidate MN.

24. A communication method, characterized in that, The method includes: The source master node MN sends first information to the terminal, wherein the first information includes configuration information of the candidate cell, the candidate cell is controlled by the candidate MN, and the first information carries a secondary node SN key counter. The SN key counter is used by the terminal to determine the secondary key of the SN when it switches to the target master cell PCell, updates the master key of the MN where the target PCell is located, and the SN remains unchanged.

25. The method according to claim 24, characterized in that, The first information configuration associates all candidate cells with the same SN key counter.

26. The method according to claim 24, characterized in that, The first information configures a candidate cell or a list of candidate cells to be associated with an SN key counter.

27. The method according to claim 24, characterized in that, The first information configuration associates a candidate cell list with an NCC list, and an NCC list with an SN key counter list, and the elements in the associated NCC list and SN key counter list have a one-to-one correspondence.

28. The method according to claim 26 or 27, characterized in that, Candidate cells in the same candidate cell list are configured with the same identifier.

29. The method according to any one of claims 26-28, characterized in that, The method further includes: The source MN obtains the NCC list associated with the candidate cell list from the candidate MN.

30. A key update device, characterized in that, include: The processing module is configured to, when switching to the target primary cell PCell, updating the master key of the primary node MN where the target PCell is located, and keeping the secondary node SN unchanged, determine the secondary key of the SN based on the master key and the SN key counter, wherein the SN key counter is determined by at least one of the following methods: The agreement stipulates; The source MN is pre-configured; Switch command carrying.

31. A communication device, characterized in that, include: The first sending module is used to send first information to the terminal, wherein the first information includes configuration information of candidate cells, and the candidate cells are controlled by candidate MN; The second sending module is used to send a handover command to the terminal to switch to the target primary cell PCell, wherein the target PCell is one of the candidate cells; The first information and / or the switching command carries an SN key counter, which is used by the terminal to determine the secondary key of the SN when switching to the target PCell, updating the primary key of the MN where the target PCell is located, and keeping the secondary node SN unchanged.

32. A communication device, characterized in that, include: The first sending module is used to send first information to the terminal, wherein the first information includes configuration information of candidate cells, the candidate cells are controlled by candidate MN, and the first information carries a secondary node SN key counter, the SN key counter is used by the terminal to determine the secondary key of SN when switching to target primary cell PCell, updating the primary key of the MN where the target PCell is located, and the SN remains unchanged.

33. A terminal, characterized in that, It includes a processor and a memory, the memory storing a program or instructions that can run on the processor, the program or instructions being executed by the processor to implement the steps of the key update method as described in any one of claims 1 to 14.

34. A network-side device, characterized in that, It includes a processor and a memory, the memory storing a program or instructions that can run on the processor, the program or instructions being executed by the processor to implement the steps of the key update method as described in any one of claims 15 to 29.

35. A readable storage medium, characterized in that, The readable storage medium stores a program or instructions that, when executed by a processor, implement the key update method as described in any one of claims 1 to 14, or implement the steps of the key update method as described in any one of claims 15 to 29.

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