Method, apparatus and system for SCG security in wireless network

Abstract

The present disclosure generally relates to methods, devices and systems for ensuring security related to SCG and / or SN in a wireless network. A method performed by a wireless device is disclosed. The method can comprise the following steps: selecting a target PScell; the target PScell is associated with a target SN; determining whether the SW counter needs to be updated; when it is determined that the SW counter needs to be updated, the SW counter is progressively increased by a predefined value; and updating the security key based on the incremented SW counter and the base key; and transmitting, to the master node or the target SN, a first message requesting a handover from the current PScell to the target PScell, the first message comprising at least one of: an indicator indicating that a security key in the target SN needs to be updated; or incrementing the value of the SW counter.

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 has been introduced, in which two base stations are used to support the main carrier group (MCG) and SCG. Switching between SCGs and adding new SCGs, as well as switching between cells within the same SCG, are supported to achieve robust secondary connectivity. Minimizing the execution time and improving the performance of these processes is critical. Summary of the invention

[0003] The present disclosure relates to methods, devices, and systems for ensuring security associated with SCGs and / or SNs in a wireless network.

[0004] In some embodiments, a method performed by a wireless device is disclosed. The method may include: in response to satisfying an execution condition, 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 associated with a SW counter (SN handover counter); the SW counter and a basic key specific to the target SN are used to derive a security key; the security key is specific to the target SN and is used to protect data between the wireless device and the target SN; and synchronizing the SW counter and the basic key between the wireless device and the target SN; determining whether the SW counter needs to be updated; when determining that the SW counter needs to be updated: incrementing the SW counter by a predefined value, wherein the incremented SW counter is different from any previous SW counter used by the wireless device to derive the security key since the last reset of the SW counter; and updating the security key based on the incremented SW counter and the basic key.

[0005] The above method may also include: transmitting a first message to the master node or the target SN requesting to switch from the current PScell ​​to the target PScell, wherein: when it is determined that the SW counter needs to be updated, the first message includes at least one of the following: an indicator indicating that the security key in the target SN needs to be updated; or the value of the incremented SW counter.

[0006] In some embodiments, there is a wireless device or a network element 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 drawings, 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 with a gNB acting as a master node (MN) and an eNB acting as a secondary node (SN) is shown.

[0013] Figure 5 An exemplary SN addition / modification process initiated by a master node (MN) is shown.

[0014] Figure 6 An exemplary SN configuration pre-configured in the UE is shown.

[0015] Figure 7 An exemplary K is shown SN 'Export process.

[0016] Figure 8 An exemplary scheme for maintaining and synchronizing a SW counter (SN switch counter) between a UE and a SN is shown.

[0017] Fig. 9 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.

[0018] Fig.10 Another exemplary CPC / CPA procedure initiated by a UE pre-configured with candidate SCGs (or candidate SNs) is shown. DETAILED DESCRIPTION

[0019] Wireless communication network

[0020] Figure 1An 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). Figure 1 Other functions that may be included in the core network 110 are not shown. RAN 120 also includes multiple base stations, for example, 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 UMTS NodeB. eNB 122 communicates with MME 112 via an S1 interface. Both eNB 122 and gNB 124 can be connected to AMF 114 via an Ng interface. Each base station manages and supports at least one cell. For example, base station gNB 124 can be configured to manage and support cell 1, cell 2, and cell 3.

[0021] The gNB 124 may include a central unit (CU) and at least one distributed unit (DU). The CU and the DU may be located at the same location or separated at 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.

[0022] 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 cells that may be managed by other base stations. 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 the base station to communicate with the base station via an over-the-air (OTA) wireless communication interface and resources, and may reselect a cell for communication as the UE 160 travels in the wireless communication network 100. For example, the UE 160 may initially select cell 1 to communicate with the base station 124, and may then reselect cell 2 at a later point in time. The cell selection or reselection of the UE 160 may be based on the wireless signal strength / quality and other factors in the various cells.

[0023] The wireless communication network 100 can be implemented as, for example, a 2G, 3G, 4G / LTE or 5G cellular communication network. Accordingly, base stations 122 and 124 can be implemented as 2G base stations, 3G NodeBs, LTE eNBs or 5G NR gNBs. UE 160 can 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 can support side link communication to another UE via a PC5 interface.

[0024] Although the following description focuses on Figure 1 A cellular wireless communication system is 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.

[0025] 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 embodiment, the example electronic device 200 may include a wireless transmit / receive (Tx / Rx) circuit 208 to transmit / receive communications with a UE and / or other base stations. Optionally, in one embodiment, the electronic device 200 may also include a network interface circuit 209 to enable the base station to communicate with other base stations and / or the core network, for example, 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 to communicate with an operator or the like.

[0026] The electronic device 200 may further include a system circuit 204. The system circuit 204 may include one or more processors 221 and / or a 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 that support 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.

[0027] Figure 3An example of an electronic device for implementing a terminal device 300 (e.g., a user equipment (UE)) is shown. UE 300 may be a mobile device, such as a smartphone 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 304, an input / output interface (I / O) 306, a display circuit 308, and a memory 309. The display circuit may include a user interface 310. The system circuit 304 may include any combination of hardware, software, firmware, or other logic / circuits. The system circuit 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 circuits. The system circuit 304 may be part of an implementation of any desired function in UE 300. In this regard, the system logic 304 may include logic that, for example, facilitates decoding and playing music and videos, such as MP3, MP4, MPEG, AVI, FLAC, AC3, or WAV decoding and playback; running applications; accepting user input; saving and retrieving application data; establishing, maintaining, and terminating cellular phone calls or data connections, such as 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. Additional 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.

[0028] Reference Figure 3, the communication interface 302 may include a radio frequency (RF) transmission (Tx) and reception (Rx) circuit 316, which processes 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, 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 transmitted and received signals 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.

[0029] Reference Figure 3 , the system circuit 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 embodiments, the system power of the UE 300 may be provided by a power storage device such as a battery or a transformer.

[0030] Network deployment with dual connectivity

[0031] 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) function has been 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 supporting DC deployment may include, for example, an LTE evolved packet core (EPC) or a 5G core.

[0032] In a DC deployment, one of the nodes acts as a master node (MN) and the other acts as a secondary node (SN). In some example embodiments, the MN is the node to which the UE first connects. Subsequently, the UE may connect to the SN.

[0033] 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 traffic.

[0034] In some example embodiments, the SN may also carry signaling messages.

[0035] Example DC configurations include EN-DC (E-UTRA-NR dual connectivity), NE-DC (NR–E-UTRA dual connectivity), NR-DC (new air interface dual connectivity), NGEN-DC (NG-RAN–E-UTRA dual connectivity), etc. 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 (in EN-DC), ng-eNB (in NE-DC), or gNB (in NR-DC and NGEN-DC).

[0036] 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 the 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 may implicitly imply the MN to which it is associated and an SCG may implicitly imply the SN to which it is associated.

[0037] Reference Figure 4 To obtain an example DC configuration. In this example, MCG 410 is associated with MN which is a gNB and SCG 412 is associated with SN which is an eNB.

[0038] 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 PCell and two SCells: Scell ​​1 and Scell ​​2. SCG 412 is configured with one PSCell and two SCells: Scell ​​1 and Scell ​​2.

[0039] In some implementations, the UE may be configured with multiple candidate SCGs (or SNs). The UE may be connected to one MN but may switch from one SCG to another SCG; or the UE may switch PScells within the same SCG.

[0040] In the following embodiments and example implementations, the UE may be configured with a DC configuration.

[0041] SN Addition / Modification Process (MN Initiated)

[0042] In some example embodiments, the MN may add or change (modify) a SN. 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 shown.

[0043] Step 1

[0044] The UE establishes a Radio Resource Control (RRC) connection with the MN.

[0045] Step 2

[0046] The MN sends an SN add / modify request to the SN via the Xn-C interface 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. The UE security capabilities and user plane (UP) security policies can also be sent to the SN.

[0047] UE security capabilities may include capabilities for Next Generation Radio Access Network (NG-RAN), 5G Non-Access Stratum (NAS), 5G Access Stratum (AS), and if the UE supports these access types, may also include capabilities for Evolved Packet System (EPS), Universal Terrestrial Radio Access Network (UTRAN), and GSM EDGE Radio Access Network (GERAN). 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.

[0048] In case of PDU separation, the request may also include the UP integrity protection and ciphering activation decision from the MN.

[0049] Step 3

[0050] 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 configured list and also present in the UE security capabilities. If a new K is delivered to the SN in step 2SN , then the SN can calculate the RRC key and the UP key. The SN can then activate the UP security policy based on the UP key.

[0051] Step 4

[0052] The SN sends a SN Addition / Modification Confirmation to the MN indicating the availability of the requested resources and the identifiers of one or more selected algorithms for the requested Data Radio Bearers (DRBs) and / or Signaling Radio Bearers (SRBs) of the UE. UP integrity protection and ciphering indications may also be sent to the MN.

[0053] Step 5

[0054] The MN sends an RRC connection reconfiguration request to the UE, instructing 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 the K of the SN SN The MN forwards the UE configuration parameters (which contain one or more algorithm identifiers 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.

[0055] Please note that this message can be 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.

[0056] Step 6

[0057] The UE accepts the RRC Connection Reconfiguration Request after verifying its integrity. If the SN Counter parameter is included, the UE calculates the K of the SN SN The UE may also calculate the required RRC keys and UP keys and activate RRC and UP protection according to the indication of the associated SRB and / or DRB received. 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 using the SN.

[0058] Step 7

[0059] The MN sends an SN reconfiguration completion 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.

[0060] In this SN addition / modification process, K SNUsed to protect the connection between UE and SN. UE can calculate K by itself SN , while SN relies on MN to deliver K SN .

[0061] In some example embodiments, K SN K may be derived by a key derivation function (KDF). The KDF may be based on a hash-based message authentication code secure hash algorithm 256 (HMAC-SHA-256). Equation 1 below shows the use of a KDF to derive K SN Example:

[0062] K SN = KDF (key, S) (1)

[0063] In Equation 1, the KDF has two inputs: an input key and a string S. For example, by using Equation 2 below, the string S can be the concatenation of multiple strings (or multiple input parameters):

[0064] S = FC || P0 || L0 || P1 || L1 || … || Pn || Ln (2)

[0065] In Equation 2, FC is the function code. In the connection, there are multiple parameters (from P0 to Pn, n is a non-negative integer), and the length value of each parameter (ie, L0, L1, ... Ln).

[0066] As an example, to derive K SN , the following input can be used:

[0067] -fc=0x79.

[0068] - P0 = non-negative integer value of the SN counter.

[0069] - L0 = length of P0 (ie, the length of the SN counter value, eg in bits or bytes).

[0070] The input key may be a key for the MN, which may include K eNB , and when the MN is a gNB, it may include K gNB .

[0071] Selectively add / change SCGs using pre-configuration

[0072] In the SN addition / modification process described in the previous section, the decision to add / modify the SN is made by the MN. Once 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 cause 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 effort.

[0073] One solution is to move the preparation work or the preparation phase to an earlier stage, before the SN addition / modification decision is made.

[0074] 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 serving different purposes, such as execution conditions for SN addition and execution conditions for SN modification. In addition, in some example embodiments, 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 satisfied execution conditions.

[0075] SN configuration can be used for conditional PScell ​​addition (CPA) and / or conditional PScell ​​change (CPC) because PScell ​​addition and PScell ​​change are triggered when the conditions defined by the execution conditions are met.

[0076] 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 pre-configured to the UE. Based on these pre-configured 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.

[0077] 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 negotiation efforts after selecting a candidate SN for SN addition or modification.

[0078] SN key (K SN )Conversion

[0079] In some embodiments, the link between the UE and the SN (or the PScell ​​in the SN) is composed of a K SN The converted key (SN's security key, which can be derived using equations 1 and 2) is protected and is denoted as K SN '. For example, Figure 4 As shown, the link between the UE and the PScell ​​in SCG412 can be composed of K SN 'To protect. SN 'Synchronize between UE and SN.

[0080] Figure 7 An exemplary K for each candidate SN in the candidate SN pool is shown. SN 'Derivation process. In this example, there are 3 SNs (SN 1 to SN 3). From the UE side, the UE can be pre-configured with an SN counter, which is pre-configured by, for example, the MN as a non-negative integer (e.g., 0). First, the UE can calculate the security key K for each SN SN , as shown in Table 1.

[0081] Table 1: K SN Export

[0082]

[0083] The root key may be used for MN (such as Figure 4 When the MN is an ng-eNB, it may include K eNB , and when the MN is a gNB, it may include K gNB Note that the root key may be the same for all candidate SNs in the candidate SN pool (because all these candidate SNs are associated with the same MN).

[0084] Using the formula in Table 1, the KDF can use the same root key as the input key, but each SN uses a different input string. Therefore, the security key K for each SN is SN are different.

[0085] Then, K of each SN SN It will be used to derive the K corresponding to SN. SN Another counter (SN switching counter) is further introduced and pre-configured on the UE side (in Figure 7 The SW counter may be preconfigured by, for example, the MN to an initial integer value, such as 0. The UE may then use the KDF to derive K SN '. As some examples, K SN '1=KDF(K SN 1, "SW counter based string"); or KSN '2=KDF(K SN 2, “String based on SW counter”). Note that for the same base key K SN , K can be refreshed by refreshing the SW counter SN ' (eg, by increasing the SW counter by a predefined integer, such as 1). In the following embodiments, how to determine when the SW counter needs to be refreshed will be described in detail.

[0086] Base key K SN Synchronize between UE and corresponding SN. For example, SN 1 keeps the same K as UE. SN 1 copy. The synchronization may be coordinated, for example, by the MN via signaling. In some example embodiments, the MN may SN Send to the corresponding SN, and UE can calculate K by itself SN .

[0087] The SW counter is synchronized between the UE and the SN in various forms.

[0088] In some example embodiments, the SW counter is synchronized between the UE and each candidate SN. The UE may maintain a SW counter for each candidate SN, and each candidate SN maintains its own SW counter. Figure 8 As shown, the UE may maintain three SW counters: SW counter 1, SW counter 2, and SW counter 3, serving SN 1, SN 2, and SN 3, respectively. Each SN may maintain its own SW counter corresponding to the SW counter on the UE side to form a SW counter pair. Each pair of SW counters may be initialized to the same initial value (e.g., 0). When a candidate SN is selected as a target SN, if the SW counter needs to be refreshed, the UE may notify the target SN of the refreshed SW counter value or an indicator indicating that the SW counter needs to be refreshed to keep the SW counters synchronized.

[0089] In some other example implementations, the SW counter only needs to be synchronized between the UE and the target SN. The target SN is the candidate SN associated with the selected PScell ​​under the CPC / CPA process. For example, the target SN may be the candidate SN to which the UE changes the PScell ​​(i.e., switches the link to a new PScell ​​under the target SN). The UE may notify the target SN of the refreshed SW counter value.

[0090] Since the UE and the target SN have synchronized basic keys (K SN ) and SW counter, so K SN ' can be calculated on each side and synchronized between UE and target SN.

[0091] K SN ' can be derived in various ways by using the KDF with different input strings, as described below.

[0092] For example, K SN '=KDF(K SN , input string). Refer to Equation 2 for details on how the input parameters form the input string.

[0093] In some example implementations, the following input parameters may be used:

[0094] -FC=0x7E.

[0095] - P0 = non-negative integer value of SW counter.

[0096] - L0 = length of the SW counter value (eg, 1 byte, 2 bytes, etc.).

[0097] In some example implementations, the following input parameters may be used:

[0098] -FC=0x7E.

[0099] - P0 = non-negative integer value of the SP-counter.

[0100] - L0 = length of SP-counter value.

[0101] - P1 = PSCell id of the target PScell ​​or ARFCN-DL (absolute radio frequency channel number in downlink direction, eg, absolute frequency of the SSB (synchronization signal / PBCH block) of the target PScell).

[0102] - L1 = PSCell id or length of ARFCN-DL.

[0103] In some example implementations, the following input parameters may be used:

[0104] -FC=0x7E.

[0105] - P0 = non-negative integer value of the SP-counter.

[0106] - L0 = length of SP-counter value (ie 0x00 0x02).

[0107] -P1 = PSCell id of target PScell.

[0108] -L1 = length of PSCell id.

[0109] - P2 = ARFCN-DL of target PScell.

[0110] - L2 = length of ARFCN-DL (ie 0x00 0x03).

[0111] Example 1: Selective SCG Addition / Change with Security Key Refresh

[0112] In this embodiment, the UE is pre-configured with candidate SN / SCG configuration to speed up the CPC / CPA process. SN Synchronize between the UE and each candidate SN. Note that K SN can be derived based on Equation 1 described previously. As described in the previous section, K SN The transformation, denoted as K SN ', maintained by the UE and each candidate SN, and used to protect the link between the UE and the corresponding candidate SN.

[0113] During the CPA / CPC process, the UE can stick to 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. According to different PScell ​​addition / switching scenarios, the K of the SN used to protect the link between the UE and the SN SN ' may be reused, or may need to be refreshed to enhance security. In this embodiment, K is described in detail SN 'Refresh mechanism.

[0114] 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 for the candidate SNs is used, i.e., K SN ', as described in the previous section. K SN ' can be derived as described in the previous section, for example, K SN '=KDF(K SN , “SW counter-based string”). In particular, the input key may be a security key for the SN, which is also referred to as a key for calculating K SN ' ...

[0115] 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.

[0116] Fig. 9 An example message flow of a UE-initiated CPC / CPA procedure is shown, which includes the following steps.

[0117] Step 0

[0118] This step can be used as a pre-configuration phase.

[0119] The UE may be pre-configured with a candidate SN pool (or SCG pool), which includes multiple candidate SNs (or multiple candidate SCGs). Figure 6 For each candidate SN, the configuration maintained by the UE includes: a conditional PScell ​​addition (CPA) configuration; and / or a 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 condition is met, subsequent PScell ​​addition may be performed according to the CPA configuration.

[0120] In some example implementations, for each candidate SN (or candidate SCG), the UE may be pre-configured with an SN counter. The MN may assign a unique initial value to each SN counter. For example, Figure 6 As shown, the initial values ​​of the three SN counters can be: 0, 1 and 2 respectively.

[0121] Alternatively, in certain other example embodiments, the UE only needs to maintain one SN counter as a basic counter and will derive a corresponding SN counter value to be applied to each SN. For example, the basic value pre-configured to the SN counter may be 0, and the UE may start from the basic value and derive / assign a counter value for each SN, for example, by incrementing the SN counter value after each assignment. Exemplarily, the UE may receive the basic counter from the MN.

[0122] As mentioned before, the UE also maintains one or more SW counters depending on the specific implementation. The basic principle or requirement is that the SW counters are synchronized between the UE and the target SN (for hosting the selected PScell ​​in the case of CPC / CPA). For details on how to maintain and synchronize the SW counters, please refer to "SN Key (K SN ) section.

[0123] On the SN side, each candidate SN can prepare in advance for the subsequent CPC / CPA execution. Each SN can be pre-configured with an SN counter and a SW counter synchronized with the UE. For example, the initial value of the SP counter can be set to "0". Each SN can also obtain its K SN , which K can then be calculated in this step or in a subsequent step before the first CPC / CPA process SN '.

[0124] Step 1

[0125] 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 may be different.

[0126] As an example, refer to Figure 8 , the UE is pre-configured with 3 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.

[0127] Step 2

[0128] The UE triggers the CPC / CPA procedure for 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., the candidate SN associated with the selected PSCell); or an identifier, such as the PSCell id of the selected PSCell, for identifying the target SN associated with the selected PScell.

[0129] The SW 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 different from the SN associated with the current PScell ​​in the dual connectivity, the SW counter needs to be refreshed. Accordingly, the K of the candidate SN SN ' may also need to be updated, and the UE will need to recalculate K based on the refreshed SW counter SN When it is determined that the SW counter needs to be refreshed, the CPC / CPA request message may further include a SW counter refresh indicator indicating that the SW counter needs to be refreshed, or a refreshed SW counter value.

[0130] As an example, return 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 SW counter of SN 2 (i.e., the SN associated with the selected PScell) needs to be refreshed, and the K counter of SN 2 needs to be updated. SN '.

[0131] As another example, in Figure 8In the example, it is assumed 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 the same SN. In this case, there is no SN change, so the SW counter of SN 1 does not need to be refreshed, and the K counter of SN 1 is refreshed. SN ' can be reused without updating.

[0132] In some example embodiments, the UE maintains a SW counter for each SN. When refreshing the SW counter of a selected candidate SN, the UE may increase the SW counter value by an offset (e.g., a predefined positive integer, such as 1) to obtain a refreshed value of the SW counter of the selected candidate SN (i.e., the target SN). Note that the refreshed value is required to have not been used to calculate the K of the same candidate SN. SN '. The offset can be configured by the MN.

[0133] As an example, assume that before the SW counters are refreshed, the UE maintains 3 SW counters (one for each SN) with the following values:

[0134] SW counter 1: 0; SW counter 2: 1; SW counter 3: 2.

[0135] Assuming that the UE needs to refresh the SW counter 2 (for SN 2) based on the above determination logic, the UE may increase the SW counter 2 by 1. After refreshing, the 3 SW counters have the following values ​​(the value of SW counter 2 has been updated):

[0136] SW counter 1: 0; SW counter 2: 2; SW counter 3: 2.

[0137] Since the SW counter has an upper limit, if the SW counter reaches its upper limit, the counter will reset (this may be referred to as SW counter wraparound). Each reset marks a new cycle of the SW counter. In such a reset event, for example, the MN may update all SN counters to different values. This type of SN counter update may be viewed as a reinitialization of SN counters with different initial values. For example, the initial SN counter values ​​{0, 1, 2} may be suitable for 3 candidate SNs. After reinitialization, the SN counter values ​​may be reset to {3, 4, 5}. The corresponding K needs to be calculated based on the reinitialized SN counters SN , to obtain the updated K SN Used to export K SN '. Therefore, when considering SW counter wraparound / reset, it is required that within each cycle of the SW counter, the refreshed SW counter value should not be used to calculate the K of the same candidate SN SN '.

[0138] Step 3

[0139] The MN sends a CPC / CPA request message (for SN addition / modification) to the SN (ie, the target SN) via the Xn-C interface, for example. Exemplarily, the MN may transparently forward the SN addition / modification request to the SN.

[0140] Step 4

[0141] If the SW counter refresh indicator or the refreshed SW counter value is carried in the CPC / CPA request message, the SN determines that the SW counter needs to be refreshed after receiving the CPC / CPA request message. The SN continues to update its K by using the same key derivation method as the UE. SN '. That is, K SN ' is based on the basic key (K SN ) and the string is derived based on the SW counter value. Note that the base key and SW counter are synchronized between SN and UE.

[0142] Step 5

[0143] The SN sends a CPC / CPA 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 upon receiving a Random Access Request from the UE. Note that if an updated K of the SN is required in step 2 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.

[0144] Step 6

[0145] MN sends CPC / CPA request confirmation message to UE. After receiving the message, UE can SN 'The selected encryption / decryption and integrity protection keys are activated using SN at this time.

[0146] In this embodiment, the UE maintains a SW counter (e.g., Figure 8 , SW counter 1 to SW counter 3). When the UE switches to a PScell ​​under a target SN different from the current SN associated with the current PScell, the SW counter of the target SN is refreshed, and both the UE and the target SN calculate a new K SN '. Updated K SN'Will be used to protect the link between the UE and the target SN (for example, the link between the UE and the target PScell ​​of the target SN).

[0147] Alternatively, a single SW counter implementation may be used, as previously described.

[0148] Example 2: Selective SCG Addition / Change with Security Key Refresh

[0149] This embodiment is similar to Embodiment 1. For example, for synchronizing the SW counter and K SN The basic principles and mechanisms of ' still apply. One difference is related to the participation of the MN in the entire CPC / CPA process. Specifically, in the preparation phase (as shown in step 0 of embodiment 1), various resources such as wireless resources and transport network resources can be prepared in the candidate SN and the UE. Therefore, the UE and the candidate SN can communicate with each other directly without the participation of the MN.

[0150] Fig.10 An example message flow of a UE-initiated CPC / CPA procedure is shown, where the UE and the candidate SN (target SN) communicate / negotiate directly after a preparation phase. The procedure includes the following steps.

[0151] Step 0

[0152] This is a pre-configured preparation step. See step 0 of Example 1 for details.

[0153] Step 1

[0154] The UE evaluates the execution condition for triggering CPC / CPA. See step 1 of embodiment 1 for details.

[0155] Step 2

[0156] This step is similar to step 2 of embodiment 1, except that the UE directly sends a CPC / CPA request message to the target SN without the participation of the MN.

[0157] Step 3

[0158] If the SW counter refresh indicator or the refreshed SW counter value is carried in the CPC / CPA request message, the SN determines that the SW counter needs to be refreshed after receiving the CPC / CPA request message. The SN continues to update its K by using the same key derivation method as the UE. SN '. That is, K SN ' is based on the basic key (K SN ) and the string is derived based on the SW counter value. Note that the base key and SW counter are synchronized between SN and UE.

[0159] Step 4

[0160] Step 4 is similar to step 5 of embodiment 1, except that the SN directly sends a CPC / CPA request confirmation message to the UE without the participation of the MN.

[0161] After receiving the CPC / CPA request confirmation message, the UE can SN 'The selected encryption / decryption and integrity protection keys are activated using SN at this time.

[0162] 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. The scope of the subject matter claimed or covered is quite broad. Among other things, 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, the embodiments may, for example, take the form of hardware, software, firmware, storage media, or any combination thereof. For example, the above method embodiments may be implemented by a component, device, or system including a memory and a processor by executing computer code stored in a memory.

[0163] Throughout the specification and claims, terms may have nuanced meanings suggested or implied by the context, beyond the explicitly stated meanings. 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 a combination of all or part of the exemplary embodiments.

[0164] In general, terms can be understood at least in part from usage in context. For example, terms such as "and", "or" or "and / or" used in this document can include various meanings, which can depend at least in part on the context in which the terms are used. Typically, "or" if used in an associative list, such as A, B, or C, means A, B, and C (here in an inclusive sense), as well as A, B, or C (here in an exclusive sense). In addition, the term "one or more" used in this document, depending at least in part on the context, can be used to describe any feature, structure, or characteristic in a singular sense, or can be used to describe a combination of features, structures, or characteristics in a plural sense. Similarly, terms such as "one", "an", or "the" can be understood to mean singular usage 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 rather to allow for the presence of other factors that are not necessarily explicitly described, depending at least in part on the context.

[0165] References to features, advantages, or similar language in this specification do not imply that all features and advantages that may be achieved by the present solution should be or are included in any single embodiment 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 need not, refer to the same embodiment.

[0166] Furthermore, the described features, advantages, and characteristics of the present solution may be combined in any suitable manner in one or more embodiments. Based on the description herein, one of ordinary skill in the relevant art will recognize that the present solution may be implemented without one or more of the specific features or advantages of a particular embodiment. In other cases, additional features and advantages may be recognized in certain embodiments that may not be present in all embodiments of the present solution.

Claims

1. A wireless communication method performed by a wireless device in a wireless network, comprising: In response to the execution condition being met, a target primary secondary cell PScell ​​is selected in the radio access network RAN, and the target PScell ​​is associated with a target secondary node SN, wherein: The target SN is associated with a SW counter (SN switch counter); The SW counter and a base key specific to the target SN are used to derive security keys; The security key is specific to the target SN and is used to protect data between the wireless device and the target SN; and The SW counter and the basic key are synchronized between the wireless device and the target SN; Determining whether the SW counter needs to be updated; When it is determined that the SW counter needs to be updated: incrementing the SW counter by a predefined value, wherein the incremented SW counter is different from any previous SW counter used by the wireless device to derive the security key since the last reset of the SW counter; and updating the security key based on the incremented SW counter and the basic key; and transmitting a first message to the master node or the target SN requesting a switch from the current PScell ​​to the target PScell, wherein: When it is determined that the SW counter needs to be updated, the first message includes at least one of the following: an indicator indicating that the security key in the target SN needs to be updated; or Increment the SW counter value.

2. The method according to claim 1, wherein: Determining whether the SW counter associated with the target SN needs to be updated includes: In response to the SN associated with the target PScell ​​being different from the SN associated with the current PScell, it is determined that a SW 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 primary connection between the wireless device and the master node, and a secondary connection between the wireless device and the current PScell.

4. The method according to claim 1, wherein: The initial value of the SW counter is preconfigured by the master node as an integer value.

5. The method according to any one of claims 1 to 4, wherein: The base key is derived by using a key derivation function based on at least one of the following inputs: the root key of the master node; or An SN counter based on an initial SN counter value configured by the master node.

6. The method according to any one of claims 1 to 4, wherein: The resetting of the SW counter is triggered by a wraparound of the SW counter, the method further comprising resetting the base key.

7. The method according to any one of claims 1 to 4, wherein: Before selecting the target PScell ​​in response to satisfying the execution condition, the method further includes receiving an initial value of the SW counter from the master node.

8. The method according to any one of claims 1 to 4, wherein: Updating the security key based on the incremented SW counter and the base key comprises: The security key is derived using a key derivation function, wherein the input of the key derivation function includes at least one of the following: an input key based on the base key; or Includes at least the input parameter of the incremented SW counter.

9. The method according to claim 8, wherein: The input parameters also include at least one of the following: an identifier of the target PScell; or The absolute radio frequency channel number ARFCN-DL in the downlink direction of the target PScell.

10. The method according to claim 9, wherein: The input parameters also include at least one of the following: a first length of the target PScell ​​identifier; or The second length of the ARFCN-DL of the target PScell.

11. The method according to any one of claims 1 to 4, further comprising: A second message is received from the master node or the target SN, the second message indicating that the target SN is ready to establish a secure connection with the wireless device based on an updated security key.

12. The method according to claim 11, further comprising: A security configuration associated with the target PS cell is activated based on the updated security key.

13. The method according to any one of claims 1 to 4, wherein: The wireless device is configured with a candidate SN list; The target SN belongs to the candidate SN list; and Each candidate SN in the candidate SN list is associated with a corresponding SW counter.

14. The method according to claim 13, further comprising: An initial value of each SW counter corresponding to each candidate SN in the candidate SN list is received from the master node.

15. The method according to any one of claims 1 to 4, wherein: Each of the master node and the target SN includes a base station, and the base station includes one of the following: gNodeB(gNB); eNodeB (eNB); ng-eNodeB (ng-eNB); or NodeB.

16. A wireless communication device 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 of any one of claims 1-15.

17. 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 of any one of claims 1-15.

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