Method, apparatus and system for SCG security in wireless networks

Abstract

The present disclosure generally relates to a method, device and system for ensuring security related to SCG in a wireless network. A method performed by a wireless device is disclosed. The method may comprise: selecting a target PScell, the target PScell being associated with a target SN, the target SN being a member of an SN list, each SN in the SN list being associated with an SN counter; determining whether an SN counter associated with the target SN needs to be updated; if it is determined that the SN counter associated with the target SN needs to be updated, selecting a refreshed SN counter value and updating at least the SN counter associated with the target SN with the refreshed SN counter value; and sending a first message requesting to switch from the current PScell to the target PScell to the master node.

Description

Technical Field

[0001] The present disclosure relates generally to wireless communications, and more particularly to methods, devices, and systems for ensuring security associated with a Secondary Carrier Group (SCG) and / or a Secondary Node (SN) in a wireless network. Background Art

[0002] With the rapid development of wireless communication technology, in order to meet the demand for higher speed, higher throughput and capacity, higher efficiency and lower latency, dual connectivity is introduced, in which two base stations are used to support the main carrier group (MCG) and SCG. Support switching between SCGs and the addition of new SCGs, as well as switching between cells within the same SCG, to achieve robust secondary connectivity. It is critical to minimize the execution time and improve the performance of these processes. Summary of the invention

[0003] The present disclosure relates to a method, apparatus, and system for ensuring security associated with an SCG and / or SN in a wireless network.

[0004] In some embodiments, a method performed by a wireless device is disclosed. The method may include: in response to an execution condition being met, selecting a target primary secondary cell (PScell) in a radio access network (RAN), the target PScell ​​being associated with a target secondary node (SN), wherein the target SN is a member of an SN list, each SN in the SN list is associated with an SN counter, and the SN counter associated with each SN in the SN list is used to calculate a security key for each SN in the SN list; determining whether the SN counter associated with the target SN needs to be updated; if it is determined that the SN counter associated with the target SN needs to be updated, selecting a refreshed SN counter value, and updating at least the SN counter associated with the target SN with the refreshed SN counter value, wherein the refreshed SN counter value is different from any previous SN counter value shared between the wireless device and the primary node; and sending a first message to the primary node requesting a switch from a current PScell ​​to the target PScell, the first message including the refreshed SN counter value.

[0005] In some embodiments, a method performed by a master network node in a radio access network (RAN) is disclosed. The method may include: receiving a first message from a wireless device requesting to switch the wireless device from a current PScell ​​to a target PScell, the first message including a refreshed SN counter value for updating an SN counter, wherein the refreshed SN counter value indicates that a target SN associated with the target PScell ​​is different from an SN associated with the current PScell.

[0006] In some embodiments, there is a wireless device, a network element or a network node comprising a processor and a memory, wherein the processor is configured to read code from the memory and implement any method described in any embodiment.

[0007] In some embodiments, a computer program product includes a computer readable program medium code stored thereon, which, when executed by a processor, causes the processor to implement any method described in any embodiment.

[0008] Other aspects and alternatives of the above-described embodiments and their implementations are described in more detail in the following figures, description and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 An example wireless communication network is shown.

[0010] Figure 2 An example wireless network node is shown.

[0011] Figure 3 An example user device is shown.

[0012] Figure 4 An exemplary dual connectivity configuration is shown in which the gNB acts as a master node (MN) and the eNB acts as a secondary node (SN).

[0013] Figure 5 An exemplary SN adding / modifying process initiated by a MN is shown.

[0014] Figure 6 An exemplary SN configuration preconfigured in the UE is shown.

[0015] Figure 7 An exemplary conditional PScell ​​change (CPC) or conditional PScell ​​addition (CPA) procedure initiated by a UE pre-configured with a candidate SCG (or candidate SN) is shown.

[0016] Figure 8 A candidate SN pool having three candidate SNs and a candidate cell in each candidate SN is shown. DETAILED DESCRIPTION

[0017] Wireless communication network

[0018] Figure 1 An exemplary wireless communication network 100 is shown including a core network 110 and a radio access network (RAN) 120. The core network 110 also includes at least one mobility management entity (MME) 112 and / or at least one access and mobility management function (AMF). Other functions that may be included in the core network 110 are described in detail in the following. Figure 1120. The RAN 120 also includes a plurality of base stations, such as base stations 122 and 124. The base station may include at least one evolved NodeB (eNB) for 4G LTE, an enhanced LTE eNB (ng-eNB) or a next generation NodeB (gNB) for 5G New Radio (NR), or any other type of signal transmission / reception device, such as a UMTS NodeB. The eNB 122 communicates with the MME 112 via an S1 interface. Both the eNB 122 and the gNB 124 may be connected to the AMF 114 via an Ng interface. Each base station manages and supports at least one cell. For example, the base station gNB 124 may be configured to manage and support cell 1, cell 2, and cell 3.

[0019] The gNB 124 may include a central unit (CU) and at least one distributed unit (DU). The CU and the DU may be co-located in the same location, or may be split in different locations. The CU and the DU may be connected via an F1 interface. Alternatively, for an eNB capable of connecting to a 5G network, it may also be similarly divided into a CU and at least one DU, referred to as ng-eNB-CU and ng-eNB-DU, respectively. The ng-eNB-CU and the ng-eNB-DU may be connected via a W1 interface.

[0020] The wireless communication network 100 may include one or more tracking areas. A tracking area may include a group of cells managed by at least one base station. For example, tracking area 1, labeled 140, includes cell 1, cell 2, and cell 3, and may also include tracking areas that may be managed by other base stations and in Figure 1 The wireless communication network 100 may also include at least one UE 160. The UE may select a cell among a plurality of cells supported by a base station to communicate with the base station over an over-the-air (OTA) radio communication interface and resources, and as the UE 160 travels in the wireless communication network 100, it may reselect a cell for communication. For example, the UE 160 may initially select cell 1 to communicate with the base station 124, and may then reselect cell 2 at some later point in time. The cell selection or reselection by the UE 160 may be based on wireless signal strength / quality and other factors in the various cells.

[0021] The wireless communication network 100 may be implemented as, for example, a 2G, 3G, 4G / LTE or 5G cellular communication network. Accordingly, base stations 122 and 124 may be implemented as 2G base stations, 3G NodeBs, LTE eNBs or 5G NR gNBs. UE 160 may be implemented as a mobile or fixed communication device capable of accessing the wireless communication network 100. UE 160 may include, but is not limited to, mobile phones, laptops, tablets, personal digital assistants, wearable devices, Internet of Things (IoT) devices, MTC / eMTC devices, distributed remote sensor devices, roadside assistance devices, XR devices and desktop computers. UE 160 may also be generally referred to as a wireless communication device or a wireless terminal. UE 160 may support side link communication to another UE via a PC5 interface.

[0022] Although the following description focuses on Figure 1 The cellular wireless communication system shown, but the basic principles are applicable to other types of wireless communication systems for paging wireless devices. These other wireless systems may include, but are not limited to, Wi-Fi, Bluetooth, ZigBee, and WiMax networks.

[0023] Figure 2 An example of an electronic device 200 for implementing a network base station (e.g., a radio access network node), a core network (CN), and / or operations and maintenance (OAM) is shown. Optionally, in one implementation, the example electronic device 200 may include a radio transmit / receive (Tx / Rx) circuit system 208 for sending / receiving communications with a UE and / or other base stations. Optionally, in one implementation, the electronic device 200 may also include a network interface circuit system 209 for enabling the base station to communicate with other base stations and / or the core network, such as optical or wired interconnection, Ethernet, and / or other data transmission media / protocols. The electronic device 200 may optionally include an input / output (I / O) interface 206 for communicating with an operator or the like.

[0024] The electronic device 200 may also include a system circuit system 204. The system circuit system 204 may include (multiple) processors 221 and / or memory 222. The memory 222 may include an operating system 224, instructions 226, and parameters 228. The instructions 226 may be configured for one or more processors 221 to perform the functions of a network node. The parameters 228 may include parameters for supporting the execution of the instructions 226. For example, the parameters may include network protocol settings, bandwidth parameters, radio frequency mapping allocations, and / or other parameters.

[0025] Figure 3An example of an electronic device (e.g., user equipment (UE)) for implementing a terminal device 300 is shown. UE 300 may be a mobile device, such as a smart phone or a mobile communication module provided in a vehicle. UE 300 may include some or all of the following: a communication interface 302, a system circuit system 304, an input / output interface (I / O) 306, a display circuit system 308, and a storage device 309. The display circuit system may include a user interface 310. The system circuit system 304 may include any combination of hardware, software, firmware, or other logic / circuitry systems. The system circuit system 304 may be implemented, for example, with one or more systems on a chip (SoC), application specific integrated circuits (ASICs), discrete analog and digital circuits, and other circuit systems. The system circuit system 304 may be part of the implementation of any desired function in UE 300. In this regard, the system circuit system 304 may include logic for facilitating the following: decoding and playing music and video, such as MP3, MP4, MPEG, AVI, FLAC, AC3 or WAV decoding and playing; running applications; accepting user input; saving and retrieving application data; establishing, maintaining and terminating cellular phone calls or data connections, as an example, for Internet connections; establishing, maintaining and terminating wireless network connections, Bluetooth connections or other connections; and displaying relevant information on the user interface 310. The user interface 310 and the input / output (I / O) interface 306 may include a graphical user interface, a touch-sensitive display, tactile feedback or other tactile output, voice or facial recognition input, buttons, switches, speakers, and other user interface elements. Other examples of the I / O interface 306 may include microphones, video and still image cameras, temperature sensors, vibration sensors, rotation and orientation sensors, headphone and microphone input / output jacks, universal serial bus (USB) connectors, memory card slots, radiation sensors (e.g., IR sensors), and other types of inputs.

[0026] refer to Figure 3, the communication interface 302 may include a radio frequency (RF) transmission (Tx) and reception (Rx) circuit system 316 for processing the transmission and reception of signals through one or more antennas 314. The communication interface 302 may include one or more transceivers. The transceiver may be a wireless transceiver that includes a modulation / demodulation circuit system, a digital-to-analog converter (DAC), a shaping table, an analog-to-digital converter (ADC), a filter, a waveform shaper, a filter, a preamplifier, a power amplifier, and / or other logic for transmitting and receiving through one or more antennas or (for some devices) through a physical (e.g., wired) medium. The signals sent and received may follow any of a variety of formats, protocols, modulations (e.g., QPSK, 16-QAM, 64-QAM, or 256-QAM), frequency channels, bit rates, and encodings. As a specific example, the communication interface 302 may include a transceiver that supports transmission and reception under 2G, 3G, BT, WiFi, Universal Mobile Telecommunications System (UMTS), High Speed ​​Packet Access (HSPA) +, 4G / Long Term Evolution (LTE), and 5G standards. However, the techniques described below are applicable to other wireless communication technologies, whether from the 3rd Generation Partnership Project (3GPP), the GSM Association, 3GPP2, IEEE, or other partners or standards bodies.

[0027] refer to Figure 3 , the system circuit system 304 may include one or more processors 321 and a memory 322. The memory 322 stores, for example, an operating system 324, instructions 326, and parameters 328. The processor 321 is configured to execute the instructions 326 to implement the desired functions of the UE 300. The parameters 328 may provide and specify configuration and operating options for the instructions 326. The memory 322 may also store any BT, WiFi, 3G, 4G, 5G, or other data that the UE 300 will send or has received through the communication interface 302. In various implementations, the system power of the UE 300 may be provided by a power storage device such as a battery or a transformer.

[0028] Network deployment with dual connectivity

[0029] With the rapid development of wireless communication technology, in order to meet the demand for higher speed, higher throughput and capacity, higher efficiency and lower latency, the dual connection (DC) feature is introduced. Typically, in a DC deployment, the UE is allowed to connect to two base stations (or two nodes) and send / receive data via the two base stations. The two base stations can be of the same type. For example, both base stations can be eNB, gNB, ng-eNB, etc. The two base stations can also be of different types. The core network used to support DC deployment may include, for example, an LTE evolved packet core (EPC) or a 5G core.

[0030] In a DC deployment, one of these nodes acts as a master node (MN) and the other node acts as a secondary node (SN). In some example implementations, the MN is the node to which the UE first connects. Subsequently, the UE can connect to the SN.

[0031] In some example implementations, only the MN is used to provide a control plane connection between the UE and the core network, while the SN provides additional resources to carry user plane services.

[0032] In some example implementations, the SN may also transmit signaling messages.

[0033] Example DC configurations include EN-DC (E-UTRA-NR dual connectivity), NE-DC (NR-EUTRA dual connectivity), NR-DC (New Radio Dual Connectivity), and NGEN-DC (NR-RAN E-UTRA dual connectivity). Exemplarily, the MN can be an eNB (in EN-DC), ng-eNB (in NGEN-DC), or gNB (in NR-DC and NE-DC). The SN can be an en-gNB (EN-DC), ng-eNB (in NE-DC), or gNB (in NR-DC and NGEN-DC).

[0034] In some deployments, DC can be configured in conjunction with carrier aggregation (CA), where both MNs and SNs can be associated with multiple cells or carriers. These aggregated carriers are collectively referred to as Master Cell Group (MCG) and Secondary Cell Group (SCG). Note that an MCG is associated with a MN, and an SCG is associated with an SN. Also, note that an MCG can implicitly imply the MN to which it is associated, and an SCG can implicitly imply the SN to which it is associated.

[0035] refer to Figure 4 FIG. 4 is an example DC configuration of FIG. 4. In this example, MCG 410 is associated with a MN which is a gNB, and SCG 412 is associated with a SN which is an eNB.

[0036] The MCG may include a set of service cells associated with the MN, including a primary cell (PCell) and optionally one or more secondary cells (Scells). The SCG may include a set of service cells associated with the SN, including a primary SCG cell (PScell) and optionally one or more Scells. Figure 4 In FIG. 4 , MCG 410 is configured with one PSCell and two SCells: Scell ​​1 and Scell ​​2. SCG 412 is configured with one PSCell and two SCells: Scell ​​1 and Scell ​​2.

[0037] In some implementations, a UE may be connected to one MN but may switch from one SCG to another; or the UE may switch PScells within the same SCG.

[0038] SN Addition / Modification Process (Initiated by MN)

[0039] In some example implementations, the SN may be added or changed (modified) by the MN. For example, the UE may switch from one SCG to another SCG (ie, from one SN to another SN), and a PScell ​​change will occur. Figure 5 An exemplary overall message / signaling flow for SN addition / modification is illustrated.

[0040] Step 1

[0041] The UE establishes a Radio Resource Control (RRC) connection with the MN.

[0042] Step 2

[0043] The MN sends an SN add / modify request to the SN via Xn-C to negotiate the available resources, configurations, and algorithms (e.g., security algorithms) at the SN. If a new security key (K SN ), the MN can calculate and deliver it to the SN. UE security capabilities and user plane (UP) security policies can also be sent to the SN.

[0044] UE security capabilities may include capabilities for Next Generation Radio Access Network (NG-RAN), 5G Non-Access Stratum (NAS), 5G Access Stratum (AS), and may also include capabilities for Evolved Packet System (EPS), Universal Terrestrial Radio Access Network (UTRAN), and GSM EDGE Radio Access Network (GERAN) if the UE supports these access types. UP security policies may be used to activate UP confidentiality and / or UP integrity for one or more DRBs belonging to a PDU session associated with the UE.

[0045] In case of PDU splitting, the request may also include the UP integrity protection and ciphering activation decision from the MN.

[0046] Step 3

[0047] The SN allocates necessary resources, such as radio resources, transport network resources. The SN may also select the encryption algorithm and integrity algorithm with the highest priority from its configuration list and also present in the UE security capabilities. SN Delivered to the SN in step 2, the SN can then calculate the RRC keys and the UP keys. The SN can then activate the UP security policy based on the UP keys.

[0048] Step 4

[0049] The SN sends a SN Add / Modify Confirm to the MN, which indicates the availability of the requested resources and the identifiers of the selected (multiple) algorithms for the requested Data Radio Bearer (DRB) and / or Signaling Radio Bearer (SRB) of the UE. UP integrity protection and ciphering indications may also be sent to the MN.

[0050] Step 5

[0051] The MN sends an RRC connection reconfiguration request to the UE to instruct it to configure new DRBs and / or SRBs for the SN. The MN may include an SN counter parameter to indicate that a new K SN And the UE needs to calculate K for SN SN The MN forwards the UE configuration parameters (which contain the algorithm identifier(s) received from the SN in step 4), and the UP integrity protection and ciphering indication (received from the SN in step 4) to the UE.

[0052] Note that this message is sent via the RRC connection between the MN and the UE and uses the MN's K RRCint (RRC security key) for integrity protection. Therefore, the SN counter is tamper-proof.

[0053] Step 6

[0054] The UE accepts the RRC Connection Reconfiguration Request after verifying its integrity. If the SN Counter parameter is included, the UE calculates K for the SN SN The UE may also calculate the required RRC keys and UP keys and activate RRC and UP protection according to the received indication for the associated SRBs and / or DRBs. The UE sends an RRC reconfiguration complete message to the MN. At this point, the UE may choose to activate the selected encryption / decryption and integrity protection keys with the SN.

[0055] Step 7

[0056] The MN sends an SN reconfiguration complete message to the SN via the Xn-C interface, for example, to inform the SN of the configuration result. After receiving the message, the SN may choose to activate the selected encryption / decryption and integrity protection with the UE. Alternatively, if the SN does not activate encryption / decryption and integrity protection with the UE at this stage, the SN may activate encryption / decryption and integrity protection when receiving a random access request from the UE.

[0057] During the SN addition / modification process, K SN Used to protect the connection between UE and SN. UE can calculate K by itself SN , while SN relies on MN to deliver K SN .

[0058] In some example implementations, K SN The KDF can be derived by a key derivation function (KDF). The KDF can be based on the Hash-based Message Authentication Code Secure Hash Algorithm 256 (HMAC-SHA-256). The following equation 1 shows the use of KDF to derive K SN Example:

[0059] KSN = KDF (key, S) (1)

[0060] In Equation 1, the KDF has two inputs: the input key and the string S. For example, by using Equation 2 below, the string S can be the concatenation of multiple strings:

[0061] S=FC||P0||L0||P1||L1||...||Pn||Ln (2)

[0062] In Equation 2, FC is the function code. In the cascade, there are multiple parameters (from P0 to Pn, n is a non-negative integer), and the length of each parameter (ie, L0, L1, ... Ln).

[0063] As an example, to find K SN , the following input can be used:

[0064] -fc=0x79

[0065] - P0 = value of the SN counter as a non-negative integer

[0066] - L0 = length of P0 (i.e., length of SN counter value)

[0067] The input key may be a key for the MN. When the MN is an ng-eNB, the key may include K eNB , and when the MN is a gNB, the key may include K gNB .

[0068] Selective SCG addition / change using pre-configuration

[0069] In the SN addition / modification process described in the previous section, the decision to add / change the SN is made by the MN. After the MN triggers the process, the SN and the UE need to perform preparation work, including resource allocation, capability negotiation, and algorithm selection. The preparation work may introduce service delays. Therefore, in order to speed up the process and reduce the duration of service interruption, it is necessary to reduce or even eliminate the preparation work so that after the SN addition / modification decision is made, the link between the UE and the SN can be established with minimal workload.

[0070] One solution is to move the preparation work or the preparation phase to an earlier stage, before the SN addition / modification decision is made.

[0071] The UE may be pre-configured with a candidate SN pool including multiple candidate SNs. For each candidate SN, the UE may be configured with configurations related to, for example, resource allocation, capability negotiation, algorithm selection, etc. The UE may also be configured with execution conditions for evaluating and triggering SN addition or modification. For the same candidate SN, there may be different execution conditions for different purposes, such as execution conditions for SN addition and execution conditions for SN modification. In addition, in some example implementations, the candidate SN may support multiple configurations, for example, configurations serving different qualities of service (QoS), different security levels, or different throughputs. Accordingly, the UE may evaluate multiple execution conditions of the candidate SN, and may select an SN configuration that matches the execution conditions that are met.

[0072] The SN configuration may be used for conditional PScell ​​addition (CPA) and / or conditional PScell ​​change (CPC) in the sense that PScell ​​addition and PScell ​​change are triggered when conditions defined by execution conditions are met.

[0073] refer to Figure 6 As an example. The UE is configured with a candidate SN pool including 3 candidate SNs (SN 1 to SN 3). SN configuration and execution conditions 610, 612 and 614 are preconfigured to the UE. Based on these preconfigured configurations, the UE can add one of these SNs to add an SCG, or change its SCG from one SN to another SN. The UE can also change its PScell ​​within the same SCG.

[0074] Similarly, for each candidate SN, pre-configuration may also be performed to support the CPA / CPC process. For example, the candidate SN may be configured with UE capabilities and UE security preferences to minimize the negotiation workload after the candidate SN is selected for SN addition or modification.

[0075] Example 1: Selective SCG Addition / Change with Security Key Refresh

[0076] In this embodiment, the UE is pre-configured with candidate SN / SCG configurations to speed up the CPC / CPA process. SN is synchronized between the UE and the target SN. Note that K SN It can be derived based on equation 1 as mentioned above.

[0077] During the CPA / CPC process, the UE can continue to use the Pcell in the MCG and add a new PScell, or switch to another PScell ​​in a different or the same SCG (or SN). The UE can keep the pre-configured SN / SCG configuration and can switch back and forth to the same PScell ​​multiple times. Depending on the different PScell ​​addition / switching scenarios, the K of the SN used to protect the link between the UE and the SN SN Can be reused, or may need to be refreshed to enhance security. In this embodiment, K is described in detail. SN Refresh mechanism.

[0078] When the UE is configured with multiple candidate SNs, in order to protect the link between the UE and the candidate SNs, the security key of the candidate SNs, i.e., K SN . K SN It can be derived based on equations 1 and 2 as described above. In particular, the input key can be the security key of the MN, for example, if the MN is a gNB, the key is K gNB , and if the MN is an ng-eNB, the key is K ng-eNB . P0 may be an SN counter corresponding to a candidate SN.

[0079] In an example implementation, all candidate SNs may be associated with the same MN and thus used to derive their respective K SN The input keys can be the same.

[0080] K SN There are several security requirements. First, each candidate SN has its own unique K SN Secondly, for the same candidate SN, there is a refresh requirement, so in some cases, it is necessary to refresh or update K SN . More details will be described in the following paragraphs.

[0081] Figure 7 An example signaling / message flow of a UE initiated CPC / CPA procedure is shown, which includes the following steps.

[0082] Step 0

[0083] The UE may be pre-configured with a candidate SN pool (or SCG pool) including a plurality of candidate SNs (or a plurality of candidate SCGs). Figure 6For each candidate SN, the UE maintains configurations including: conditional PScell ​​addition (CPA) configuration; and / or conditional PScell ​​change (CPC) configuration. The UE may also be pre-configured with execution conditions corresponding to the CPA and CPC configurations. For example, when the CPA execution conditions are met, subsequent PScell ​​additions may be performed according to the CPA configurations. For each candidate SN (or candidate SCG), the UE may also be pre-configured with an SN counter. For example, in Figure 6 , SN counters 616, 618 and 620 are respectively allocated to SN 1, SN 2 and SN 3. Once the SN counters are preconfigured with their respective initial values, the UE continues to maintain / update these counters.

[0084] In some example implementations, the MN may assign a unique initial value to each SN counter. Figure 6 As shown, the initial values ​​of the three SN counters 616, 618 and 620 may be 0, 1 and 2 respectively.

[0085] On the SN side, each candidate SN can prepare in advance for subsequent CPC / CPA execution.

[0086] Step 1

[0087] The UE evaluates the execution conditions. If a specific PScell ​​under the candidate SN meets the CPA / CPC execution conditions, the UE will select the PScell ​​(and its associated candidate SN, also called the target SN) and proceed with the CPA / CPC process. The execution conditions for CPA and CPC can be different.

[0088] For example, refer to Figure 8 , the UE is preconfigured with 3 candidate SNs: SN 1, SN 2, and SN 3. Each SN has 3 cells: cell 1, cell 2, and cell 3. The UE has current dual connectivity, and the current PScell ​​is cell 1 under SN 1. If the CPC execution condition is met, the UE may select cell 2 under SN 2 to perform the CPC procedure. In this case, SN 2 is the target SN.

[0089] Step 2

[0090] The UE triggers the CPC / CPA process to the selected PSCell by sending a CPC / CPA request message to the MN. The message may include at least one of the following: an SN counter of the target SN (i.e., a candidate SN associated with the selected PSCell); or an identifier, such as the PSCell id of the selected PSCell, which is used to identify the target SN associated with the selected PSCell. One of the goals of the UE forwarding the SN counter to the MN is to keep the SN counter synchronized between the UE and the MN. Therefore, an SN counter update indication may also be included in the CPC / CPA request message instead of the SN counter itself, so that the UE and the MN can update the SN counter synchronously.

[0091] The SN counter of the target SN associated with the selected PSCell may or may not need to be refreshed (updated) from the current value. If the selected PSCell is associated with an SN that is different from the SN associated with the current PSCell in dual connectivity, the SN counter needs to be refreshed. K for candidate SNs SN K also needs to be updated, and the UE will need to recalculate K based on the refreshed SN counter SN (That is, the refresh of the SN counter triggers K SN renew).

[0092] As an example, refer to Figure 8 , assuming that the current dual connectivity uses cell 1 in SN 1 as the PScell ​​(i.e., SN 1 is the current SN), the UE determines that the PScell ​​needs to be changed to cell 2 under SN 2. In this case, since the selected PScell ​​is associated with an SN different from the current SN, the SN counter of SN 2 (the target SN, i.e., the SN associated with the selected PScell) needs to be refreshed, and the K counter for SN 2 is updated. SN Needs to be updated.

[0093] As another example, refer to Figure 8 , assuming that the current dual connectivity uses cell 1 in SN 1 as the PScell ​​(i.e., SN1 is the current SN), the UE determines that the PScell ​​needs to be changed to cell 2 under the same SN. In this case, there is no SN change, so the SN counter of the target SN (SN 1) does not need to be refreshed, and the K counter for SN 1 is SN Can be reused without updating.

[0094] In some example implementations, the UE maintains an SN counter for each SN. When refreshing the SN counter of the selected (target) SN, the UE may determine the maximum value of all SN counters maintained by it and increase the maximum value by an offset (e.g., a predefined positive integer, such as 1) to obtain a refreshed value for the SN counter of the selected SN, noting that the refreshed value has not yet been used to calculate K for any candidate SN. SN The offset can be configured by the MN.

[0095] As an example, assume that before the SN counters are refreshed, the UE maintains 3 SN counters with the following values:

[0096] SN 1 counter: 0; SN 2 counter: 1; SN 3 counter: 2.

[0097] Assuming that the UE needs to refresh the SN counter for SN 2 based on the above determination logic, the UE first determines that the maximum value of all SN counters is 2 (i.e., the SN 3 counter value), increments it by 1 to obtain the refresh value for the SN 2 counter, and updates the SN 2 counter. After the refresh, the 3 SN counters have the following values ​​(the SN 2 counter value has been updated):

[0098] SN 1 counter: 0; SN 2 counter: 3; SN 3 counter: 2.

[0099] Since the SN counter has an upper limit, if the SN counter reaches the upper limit, the counter needs to be reset. Each reset marks a new cycle of the SN counter. In such a reset event, all SN counters can be reset to, for example, their initial preconfigured values ​​(e.g., set by the MN). At the same time, the value used to derive K SN The input key of the KDF will also be updated to a new key that has not been used before. Therefore, when considering the SN counter reset, it is required that in each cycle of the SN counter, the refresh counter value should not be used to calculate the K of any candidate SN. SN .

[0100] In some example implementations, the UE maintains an SN counter for each SN. The UE may use K that has not been used to calculate any candidate SN. SN The random number is used to refresh the SN counter. The SN counter reset rules may also apply.

[0101] After receiving the updated SN counter, the MN stores the updated SN counter and calculates the updated K based thereon. SN .

[0102] Step 3

[0103] The MN sends an SN add / modify request to the SN (i.e., the target SN) via, for example, the Xn-C interface. SN MN will also K SN Delivered to SN.

[0104] Step 4

[0105] The SN sends a SN Add / Modify Request Confirmation message to the MN, for example, via the Xn-C interface. The SN may activate the selected encryption / decryption and integrity protection with the UE based on the pre-configured configuration. If the SN does not activate encryption / decryption and integrity protection with the UE at this stage, the SN may choose to activate encryption / decryption and integrity protection when receiving a random access request from the UE. Note that if in step 3, the updated K SN is sent to SN, then encryption / decryption and integrity protection are based on the updated K SN , otherwise the current K SN Can be used for security protection.

[0106] Step 5

[0107] The MN sends a CPC / CPA request confirmation message to the UE. After receiving the message, the UE can activate the selected encryption / decryption and integrity protection keys with the SN at this time.

[0108] In this embodiment, the UE maintains an SN counter (e.g., Figure 6 , SN counters 616, 618 and 620). For example, these counters may be configured by the MN to have different initial values. When the UE switches to a PScell ​​under a target SN different from the current SN associated with the current PScell, the SN counter for the target SN will be refreshed and the new K SN will be calculated.

[0109] Example 2: Selective SCG Addition / Change with Security Key Refresh

[0110] This embodiment is similar to Embodiment 1, except that the UE maintains the SN counter in a different manner.

[0111] In some example implementations, the UE maintains an SN counter for each candidate SN in the candidate SN pool. Each of these SN counters is preconfigured with the same initial value (e.g., 0). When the UE determines that the SN counter associated with the target SN needs to be refreshed (by following similar logic as described in step 2 of embodiment 1), the UE may uniformly increase all SN counters by a predefined offset (e.g., a predefined positive integer, such as 1), so that all SN counters maintain the same value. Alternatively, the UE may uniformly set all SN counters to K, which is not used to calculate any candidate SN.SN Note that the SN counter period concept described in Embodiment 1 still applies.

[0112] In some example implementations, the UE employs a single SN counter covering all candidate SNs, rather than maintaining an SN counter for each candidate SN. When the UE determines that the SN counter associated with the target SN needs to be refreshed (by following similar logic as described in step 2 of embodiment 1), the UE may increase the SN counter by a predefined offset (e.g., a predefined positive integer, such as 1). Alternatively, the UE may set the SN counter to the K value that has not been used to calculate any candidate SN. SN Note that the SN counter period concept described in Embodiment 1 is still applicable.

[0113] The above description and accompanying drawings provide specific example embodiments and implementations. However, the described subject matter may be embodied in a variety of different forms, and therefore, the subject matter covered or claimed is intended to be interpreted as not being limited to any example embodiment described herein. It is intended to provide a reasonably broad scope for the subject matter claimed or covered. In addition, for example, the subject matter may be embodied as a method, device, component, system, or non-transitory computer-readable medium for storing computer code. Therefore, for example, the embodiment may take the form of hardware, software, firmware, storage medium, or any combination thereof. For example, the above method embodiment may be implemented by a component, device, or system including a memory and a processor by executing a computer code stored in the memory.

[0114] Throughout the specification and claims, terms may have nuanced meanings that are suggested or implied by the context beyond the explicitly stated meaning. Likewise, the phrase "in one embodiment / implementation" as used herein does not necessarily refer to the same embodiment, and the phrase "in another embodiment / implementation" as used herein does not necessarily refer to a different embodiment. For example, the claimed subject matter includes combinations of all or part of the example embodiments.

[0115] In general, terms can be understood at least in part from usage in context. For example, terms used herein (such as "and", "or", or "and / or") can include various meanings that can depend at least in part on the context in which such terms are used. In general, "or" if used to associate a list (such as A, B, or C) means A, B, and C, which is used in an inclusive sense here; and A, B, or C, which is used in an exclusive sense here. In addition, the term "one or more" used in this article can be used in a singular sense to describe any feature, structure, or characteristic, and can also be used in a plural sense to describe a combination of features, structures, and characteristics, which depends at least in part on the context. Similarly, terms such as "one", "an", or "the" can be understood to convey singular or plural usage, which depends at least in part on the context. In addition, the term "based on" can be understood to not necessarily be intended to convey a set of exclusive factors, but can allow for the presence of other factors that are not necessarily explicitly described, which depends at least in part on the context.

[0116] References to features, advantages, or similar language throughout the specification do not imply that all features and advantages that may be achieved with the present solution should be or are included in any single implementation thereof. Rather, language referring to features and advantages is understood to mean that a particular feature, advantage, or characteristic described in connection with an embodiment is included in at least one embodiment of the present solution. Thus, discussion of features and advantages and similar language throughout the specification may, but do not necessarily, refer to the same embodiment.

[0117] In addition, the above-mentioned features, advantages and characteristics of the present solution can be combined in any suitable manner in one or more embodiments. Based on the description herein, a person of ordinary skill in the relevant art will recognize that the present solution can be practiced without one or more specific features or advantages of a particular embodiment. In other cases, additional features and advantages that may not be present in all embodiments of the present solution can be recognized in certain embodiments.

Claims

1. A method for wireless communication, performed by a wireless device in a wireless network, the method comprising: In response to the execution condition being satisfied, selecting a target primary secondary cell (PScell) in a radio access network (RAN), the target PScell ​​being associated with a target secondary node (SN), wherein the target SN is a member of an SN list, each SN in the SN list being associated with an SN counter, and the SN counter associated with each SN in the SN list being used to calculate a security key for each SN in the SN list; determining whether an SN counter associated with the target SN needs to be updated; Upon determining that the SN counter associated with the target SN needs to be updated, selecting a refreshed SN counter value and updating at least the SN counter associated with the target SN using the refreshed SN counter value, wherein the refreshed SN counter value is different from any previous SN counter value shared between the wireless device and a master node; as well as A first message is sent to the master node requesting a switch from the current PScell ​​to the target PScell, where the first message includes the refreshed SN counter value.

2. The method of claim 1 , wherein determining whether the SN counter associated with the target SN needs to be updated comprises: In response to the SN associated with the target PScell ​​being different from the SN associated with the current PScell, it is determined that the SN counter associated with the target SN needs to be updated.

3. The method according to claim 1, wherein the wireless device has a dual connection with the RAN, and the dual connection includes a connection between the wireless device and the current PScell. 4 . The method of claim 3 , wherein the dual connectivity further comprises a primary connection between the wireless device and the primary node. 5 . The method of claim 1 , wherein an initial value of the SN counter associated with each SN in the SN list is preconfigured as an integer value.

6. The method of claim 5, wherein the initial value of the SN counter associated with each SN in the SN list is preconfigured by the master node to be a same integer value.

7. The method of claim 6, wherein updating at least the SN counter associated with the target SN using the refreshed SN counter value comprises: The SN counter associated with each SN in the SN list is updated.

8. The method according to any one of claims 1 to 7, wherein selecting the refreshed SN counter value comprises: The maximum value among all values ​​in the SN counter associated with the SN list is monotonically increased by a predefined number to obtain the refreshed SN counter value.

9. The method according to any one of claims 1 to 7, wherein selecting the refreshed SN counter value comprises: A random integer value is selected as the refreshed SN counter value.

10. The method according to any one of claims 1 to 7, further comprising: A second message is received from the master node, the second message indicating that the target SN is ready to establish a secure connection with the wireless device based on a target SN key, the target SN key being derived based on the refreshed SN counter value.

11. The method according to claim 10, further comprising: deriving the target SN key based on the refreshed SN counter value; as well as Based on the target SN key, a security configuration associated with the target PScell ​​is activated.

12. The method according to any one of claims 1 to 7, wherein each of the master node and the SN comprises a base station, the base station comprising one of the following: gNodeB(gNB); eNodeB (eNB); ng-eNodeB (ng-eNB); or NodeB.

13. A method for wireless communication, performed by a master network node in a RAN of a wireless network, the method comprising: A first message is received from a wireless device requesting to switch the wireless device from a current PScell ​​to a target PScell, the first message comprising a refreshed SN counter value for updating an SN counter, wherein the refreshed SN counter value indicates that a target SN associated with the target PScell ​​is different from an SN associated with the current PScell.

14. The method according to claim 13, wherein the wireless device has a dual connection with the RAN, and the dual connection includes a secondary connection between the wireless device and the current PScell.

15. The method of claim 14, wherein the dual connectivity further comprises a primary connection between the wireless device and the primary network node.

16. The method according to any one of claims 13 to 15, further comprising: Updating the SN counter using the refreshed SN counter value; updating a target SN key based on the refreshed SN counter value, wherein the updated target SN key is used to protect a link between the target PScell ​​and the wireless device; as well as A second message including the updated target SN key is sent to the target SN.

17. The method according to claim 16, further comprising: receiving, from the target SN, a third message as a response to the second message; as well as A fourth message is sent to the wireless device as a response to the first message, the fourth message triggering the wireless device to activate a security configuration associated with the target PScell ​​based on the updated target SN key.

18. The method according to any one of claims 13 to 15, wherein each of the master network node and the SN comprises a base station, the base station comprising one of the following: gNodeB(gNB); eNodeB (eNB); ng-eNodeB (ng-eNB); or NodeB.

19. A device for wireless communication, comprising a memory for storing computer instructions and a processor in communication with the memory, wherein when the processor executes the computer instructions, the processor is configured to implement the method according to any one of claims 1 to 18.

20. A computer program product, comprising a non-transitory computer-readable program medium having computer code stored thereon, the computer code, when executed by one or more processors, causing the one or more processors to implement the method according to any one of claims 1 to 18.

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