Methods, devices, and systems for scg security in wireless networks

Abstract

The present disclosure relates generally 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 can comprise: selecting a target PScell, the target PScell being associated with a target SN, wherein the target SN is a member of a list of SNs, each SN in the list of SNs being associated with a SN counter; 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; and sending a first message to a master node requesting a handover from a current PScell to the target PScell.

Description

TECHNICAL FIELD

[0001] The present disclosure relates generally to wireless communications, and more specifically to methods, devices, and systems for ensuring security related to secondary carrier group (SCG) and / or secondary node (SN) in a wireless network. BACKGROUND

[0002] With the rapid development of wireless communication technology, 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 employed to support a master carrier group (MCG) and an SCG. Switching between SCGs and addition of a new SCG, as well as switching between cells within the same SCG, are supported to achieve robust secondary connectivity. It is crucial to minimize the execution time and improve the performance of these procedures. SUMMARY

[0003] The present disclosure relates to methods, devices, and systems for ensuring security related to SCG and / or SN in a wireless network.

[0004] In some embodiments, a method performed by a wireless device is disclosed. The method can include: in response to an 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 a list of SNs, each SN in the list of SNs is associated with an SN counter, and the SN counter associated with each SN in the list of SNs is used to compute a security key for each SN in the list of SNs; 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 a master node; and sending a first message to the master node requesting a handover 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 can include: receiving, from a wireless device, a first message requesting a handover of 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 a SN associated with the current PScell.

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

[0007] In some embodiments, a computer program product comprises a computer- readable program medium having code stored thereon, the code, when executed by a processor, causing the processor to implement any of the methods described in any of the embodiments.

[0008] The above embodiments and other aspects and alternatives thereof are described in more detail in the following drawings, descriptions, and claims. BRIEF DESCRIPTION OF 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 equipment is shown.

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

[0013] Figure 5 An example SN addition / modification procedure initiated by the MN is shown.

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

[0015] Figure 7 An example conditional PScell change (CPC) or conditional PScell addition (CPA) procedure initiated by the UE pre-configured with candidate SCGs (or candidate SNs) is shown.

[0016] Figure 8 A candidate SN pool with 3 candidate SNs and candidate cells in each candidate SN is shown. DETAILED DESCRIPTION

[0017] Wireless communication network

[0018] Figure 1 An example wireless communication network 100 is shown that includes 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 can be included in the core network 110 are described in 3GPP TS 23.501 v16.4.0, which is publicly available. Figure 1The RAN 120 also includes a number of base stations, such as base stations 122 and 124. The base stations can include at least one evolved Node B (eNB) for 4G LTE, an enhanced LTE eNB (ng-eNB) or next generation Node B (gNB) for 5G New Radio (NR), or any other type of signal transmission / reception device such as a UMTS NodeB. The eNB 122 is in communication with the MME 112 via an SI interface. Both the eNB 122 and the gNB 124 can 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 can be configured to manage and support cell 1, cell 2, and cell 3.

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

[0020] The wireless communication network 100 can include one or more tracking areas. A tracking area can include a set 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 can also include more cells not shown in FIG. 1 that can be managed by other base stations and in communication with other UEs. The wireless communication network 100 can also include at least one UE 160. The UE can select a cell among multiple cells supported by a base station to communicate with the base station over an over-the-air (OTA) radio communication interface and resources, and it can reselect a cell for communication as the UE 160 travels in the wireless communication network 100. For example, the UE 160 can initially select cell 1 to communicate with the base station 124, and can then reselect cell 2 at some later point in time. The cell selection or reselection by the UE 160 can be based on wireless signal strength / quality in the various cells and other factors. Figure 1

[0021] ​The wireless communication network 100 can be implemented as, for example, a 2G, 3G, 4G / LTE or 5G cellular communication network. Correspondingly, the base stations 122 and 124 can be implemented as 2G base stations, 3G NodeBs, LTE eNBs or 5G NR gNBs. The UEs 160 can be implemented as mobile or fixed communication devices capable of accessing the wireless communication network 100. The UEs 160 can include, but are not limited to, mobile phones, laptops, tablets, personal digital assistants, wearable devices, Internet of Things (loT) devices, MTC / eMTC devices, distributed remote sensor devices, road side assistant devices, XR devices and desktop computers. The UEs 160 can also be commonly referred to as wireless communication devices or wireless terminals. The UEs 160 can support sidelink communication to another UE via a PC5 interface.

[0022] While the following description focuses on a cellular wireless communication system as shown in Figure 1

[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 an operations and maintenance (OAM) is shown. Optionally, in one implementation, the example electronic device 200 can include radio transmit / receive (Tx / Rx) circuitry 208 for transmitting / receiving communications with UEs and / or other base stations. Optionally, in one implementation, the electronic device 200 can also include network interface circuitry 209, such as optical or wired interconnections, Ethernet, and / or other data transmission media / protocols, for enabling the base station to communicate with other base stations and / or a core network. The electronic device 200 can optionally include input / output (I / O) interfaces 206 for communicating with operators, etc.

[0024] The electronic device 200 can also include system circuitry 204. The system circuitry 204 can include processor(s) 221 and / or memory 222. The memory 222 can include an operating system 224, instructions 226, and parameters 228. The instructions 226 can be configured for the processor(s) 221 to perform the functions of the network node. The parameters 228 can include parameters to support execution of the instructions 226. For example, the parameters can include network protocol settings, bandwidth parameters, radio frequency mapping assignments, and / or other parameters.

[0025] Figure 3 ​An example of an electronic device (e.g., a user equipment (UE)) for implementing the terminal device 300 is shown. The UE 300 can be a mobile device, such as a smartphone or a mobile communication module disposed in a vehicle. The UE 300 can include some or all of the following: a communication interface 302, system circuitry 304, an input / output interface (I / O) 306, display circuitry 308, and a storage 309. The display circuitry can include a user interface 310. The system circuitry 304 can include any combination of hardware, software, firmware, or other logic / circuitry. The system circuitry 304 can be implemented, for example, with one or more system on a chip (SoC), application-specific integrated circuits (ASICs), discrete analog and digital circuits, and other circuitry. The system circuitry 304 can be part of the implementation of any desired functionality in the UE 300. In this regard, the system circuitry 304 can include logic to facilitate 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 telephone calls or data connections, such as for internet connectivity; 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 can include a graphical user interface, a touch-sensitive display, tactile feedback or other haptic output, voice or facial recognition input, buttons, switches, a speaker, and other user interface elements. Other examples of the I / O interface 306 can include a microphone, a video and still image camera, a temperature sensor, a vibration sensor, a rotation and orientation sensor, earphone and microphone input / output jacks, a universal serial bus (USB) connector, a memory card slot, a radiation sensor (e.g., an IR sensor), and other types of input.

[0026] Reference is made to Figure 3The communication interface 302 can include radio frequency (RF) transmit (Tx) and receive (Rx) circuitry 316 for handling transmission and reception of signals through one or more antennas 314. The communication interface 302 can include one or more transceivers. The transceivers can be wireless transceivers that include modulation / demodulation circuitry, digital to analog converters (DACs), shaping tables, analog to digital converters (ADCs), filters, waveform shapers, preamplifiers, power amplifiers, and / or other logic for transmitting and receiving through one or more antennas or, for some devices, through physical (e.g., wired) media. The signals transmitted and received can conform to 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 one specific example, the communication interface 302 can include transceivers that support transmission and reception under the 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 Third Generation Partnership Project (3GPP), GSM Association, 3GPP2, IEEE, or other partners or standards bodies.

[0027] Reference Figure 3 The system circuitry 304 can include one or more processors 321 and 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 functionality of the UE 300. The parameters 328 can provide and specify configuration and operational options for the instructions 326. The memory 322 can also store any BT, WiFi, 3G, 4G, 5G, or other data that the UE 300 will transmit or has received through the communication interface 302. In various implementations, the system power for the UE 300 can 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 technologies, to meet the demands for higher speed, higher throughput and capacity, higher efficiency, and lower latency, a dual connectivity (DC) feature is introduced. Generally, in a DC deployment, a UE is allowed to connect to two base stations (or two nodes) and transmit / receive data via the two base stations. The two base stations can be of the same type. For example, both of the base stations can be eNBs, gNBs, ng-eNBs, etc. The two base stations can also be of different types. The core network for supporting the DC deployment can include, for example, an LTE evolved packet core (EPC) or a 5G core.

[0030] In DC deployments, one of these nodes acts as a master node (MN) and the other 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 control plane connectivity between the UE and the core network. The SN provides additional resources to carry user plane traffic.

[0032] In some example implementations, the SN can 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). Illustratively, the MN can be an eNB (in EN-DC), an ng-eNB (in NGEN-DC), or a gNB (in NR-DC and NE-DC). The SN can be an en-gNB (EN-DC), an ng-eNB (in NE-DC), or a gNB (in NR-DC and NGEN-DC).

[0034] In certain deployments, DC can be configured in conjunction with carrier aggregation (CA), where both the MN and the SN can be associated with multiple cells or carriers. These aggregated carriers are collectively referred to as the master cell group (MCG) and the secondary cell group (SCG). Note that the MCG is associated with the MN and the SCG is associated with the SN. Also, note that the MCG can implicitly imply the MN with which it is associated and the SCG can implicitly imply the SN with which it is associated.

[0035] Reference Figure 4 to an example DC configuration. In this example, the MCG 410 is associated with a MN that is a gNB and the SCG 412 is associated with a SN that is an eNB.

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

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

[0038] SN addition / modification procedure (MN initiated)

[0039] In some example implementations, an SN can be added or changed (modified) by the MN. For example, the UE can handover from one SCG to another SCG (i.e., from one SN to another SN), and a PScell change will occur. Figure 5 An example 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 addition / modification request to the SN over Xn-C to negotiate available resources, configurations, and algorithms (e.g., security algorithms) at the SN. If new security keys (KsN) for the SN are needed, the MN can compute and deliver them to the SN. UE security capabilities and user plane (UP) security policies can also be sent to the SN. SN

[0044] The UE security capabilities can include capabilities for next generation radio access network (NG-RAN), 5G non-access stratum (NAS), 5G access stratum (AS), and can 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. The UP security policies can 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 the case of PDU split, the request can also include UP integrity protection and encryption activation decisions from the MN.

[0046] Step 3

[0047] The SN allocates necessary resources, such as radio resources, transport network resources. The SN can also select encryption and integrity algorithms with the highest priority and also present in the UE security capabilities from its configuration list. If new KsN are delivered in step 2 to the SN, the SN can compute RRC keys as well as UP keys. The SN can then activate UP security policies based on the UP keys. SN

[0048] Step 4​​

[0049] The SN sends an SN addition / modification acknowledgement to the MN, indicating the availability of the requested resources and the identifier of the selected algorithm(s) for the requested data radio bearers (DRBs) and / or signaling radio bearers (SRBs) of the UE. The UP integrity protection and ciphering indication can also be sent to the MN.

[0050] Step 5

[0051] The MN sends an RRC connection reconfiguration request to the UE to indicate its configuration of new DRBs and / or SRBs for the SN. The MN can include the SN counter parameter to indicate that a new K SN is needed for the 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 over the RRC connection between the MN and the UE, and is integrity protected using the MN’s K RRCint (RRC security key). Thus, 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 computes the K SN for the SN. The UE can also compute the required RRC keys and UP keys, and activate RRC and UP protection according to the received indication for the associated SRB and / or DRB. The UE sends an RRC reconfiguration complete message to the MN. At this point, the UE can select to activate the selected ciphering / deciphering and integrity protection keys with the SN.

[0055] Step 7

[0056] The MN sends an SN reconfiguration complete message to the SN, e.g., via the Xn-C interface, to inform the SN of the configuration result. After receiving this message, the SN can select to activate the selected ciphering / deciphering and integrity protection with the UE. Alternatively, if the SN does not activate ciphering / deciphering and integrity protection with the UE at this stage, the SN can activate ciphering / deciphering and integrity protection when it receives a random access request from the UE.

[0057] In this SN addition / modification procedure, K SN is used to protect the connection between the UE and the SN. The UE can compute K SN itself, while the SN relies on the MN to deliver K SN .

[0058] In some example implementations, K SN may be derived through a key derivation function (KDF). The KDF can be based on a hash-based message authentication code secure hash algorithm 256 (HMAC-SHA-256). Equation 1 below shows an example of deriving K SN using the KDF:

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

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

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

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

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

[0064] - FC = 0x79

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

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

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

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

[0069] In the SN addition / modification procedure described in the previous section, the decision of SN addition / modification is made by the MN. After the MN triggers the procedure, the SN and the UE need to do preparations, including resource allocation, capability negotiation, algorithm selection. The preparations can introduce service latency. Therefore, to speed up the procedure and reduce the duration of service interruption, the preparations need to be reduced or even eliminated so that the link between the UE and the SN can be established with minimum effort after the decision of SN addition / modification is made.

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

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

[0072] The SN configurations can 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 the execution conditions are satisfied.

[0073] Reference Figure 6 As an example. The UE is configured with a candidate SN pool including 3 candidate SNs (SN 1 to SN 3). SN configurations 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 a 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 can also be performed to support the CPA / CPC procedure. For example, a candidate SN can 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] Embodiment 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 procedure. When the UE triggers the CPC / CPA procedure, K SN Is synchronized between the UE and the target SN. Note that K SN Can be derived based on Equation 1 as previously described.

[0077] In CPA / CPC procedure, 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 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 different PScell addition / switch scenarios, the K SN s used to protect the link between the UE and the SN can be reused, or can need to be refreshed for enhanced security. In this embodiment, the K SN refresh mechanism is described in detail.

[0078] When the UE is configured with multiple candidate SNs, to protect the link between the UE and the candidate SNs, the security keys of the candidate SNs, i.e. K SN , are used. SN The K gNB s 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, e.g. K ng-eNB if the MN is a gNB, or K SN if the MN is an ng-eNB. P0 can be the SN counter corresponding to the candidate SN.

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

[0080] K SN s are unique to each candidate SN. Second, there is a refresh requirement for the same candidate SN, such that in certain cases, the K SN s need to be refreshed or updated. More details will be described in later paragraphs.

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

[0082] Step 0

[0083] The UE can be pre-configured with a candidate SN pool (or SCG pool) including multiple candidate SNs (or multiple candidate SCGs). Again, refer to Figure 6For each candidate SN, the UE maintains configurations, including: a conditional PScell addition (CPA) configuration; and / or a conditional PScell change (CPC) configuration. The UE can also be preconfigured with execution conditions corresponding to the CPA and CPC configurations. For example, when a CPA execution condition is satisfied, a subsequent PScell addition can be performed according to the CPA configuration. For each candidate SN (or candidate SCG), the UE can also be preconfigured with a SN counter. For example, in Figure 6 , the SN counters 616, 618, and 620 are assigned to SN 1, SN 2, and SN 3, respectively. 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 can assign a unique initial value to each SN counter. For example, as shown in Figure 6 , the initial values of the 3 SN counters 616, 618, and 620 can 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 particular PScell under a candidate SN satisfies a CPA / CPC execution condition, the UE will select the PScell (and its associated candidate SN, also referred to as the target SN) and proceed with the CPA / CPC procedure. The execution conditions for CPA and CPC can be different.

[0088] For example, referring 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 a current dual connectivity, and the current PScell is Cell 1 under SN 1. If a CPC execution condition is satisfied, the UE can 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 procedure towards the selected PSCell by sending a CPC / CPA request message to the MN. This message can 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 a PSCell id of the selected PSCell, which is used to identify the target SN associated with the selected PSCell. One of the target of the UE forwarding the SN counter to the MN is to keep the SN counter synchronized between the UE and the MN. Therefore, instead of the SN counter itself, an SN counter update indication can also be included in the CPC / CPA request message, so that the UE and the MN can update the SN counter in synchronization.

[0091] The SN counter of the target SN associated with the selected PSCell can or can not need to be refreshed (updated) from the current value. If the selected PSCell is associated with a SN which is different from the SN associated with the current PSCell in dual connectivity, the SN counter needs to be refreshed. The K SN value for the candidate SN also needs to be updated, and the UE will need to re-compute the K SN value based on the refreshed SN counter (i.e. the refresh of the SN counter triggers the update of the K SN value).

[0092] As an example, referring to Figure 8 , assume 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 a SN which is 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 SN value for SN 2 needs to be updated.

[0093] As another example, referring to Figure 8 , assume 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 SN counter of the target SN (SN 1) does not need to be refreshed, and the K SN value for SN 1 can be reused without update.

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

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

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

[0097] Assume that the UE needs to refresh the SN counter for SN 2 based on the above determination logic, then the UE first determines the maximum value of all SN counters as 2 (i.e., the SN 3 counter value), increments it by 1 to obtain the refreshed 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 pre-configured values (e.g., set by the MN). At the same time, the input key to the KDF for deriving K SN should also be updated to a new key that has not been used before. Thus, when considering the SN counter reset, it is required that within each cycle of the SN counter, the refreshed counter value should not be used to compute K SN for any candidate SN.

[0100] In some example implementations, the UE maintains a SN counter for each SN. The UE can refresh the SN counter with a random number that has not been used to compute K SN for any candidate SN. The SN counter reset rule can also apply.

[0101] Upon receiving the updated SN counter, the MN stores the updated SN counter and computes an updated K SN based on it.

[0102] Step 3

[0103] MN, for example, sends an SN add / modify request to SN (i.e., the target SN) via the Xn-C interface. If the new K is calculated in step 2... SN Then MN will also K SN Delivered to SN.

[0104] Step 4

[0105] The SN, for example, sends an SN add / modify request confirmation message to the MN via the Xn-C interface. The SN can activate the selected encryption / decryption and integrity protection with the UE based on a pre-configured setup. If the SN does not activate encryption / decryption and integrity protection with the UE at this stage, the SN can choose to activate encryption / decryption and integrity protection upon receiving a random access request from the UE. Note that if in step 3, the updated K... SN When sent to the SN, encryption / decryption and integrity protection are based on the updated K. SN Otherwise, the current K SN It can be used for security protection.

[0106] Step 5

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

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

[0109] Embodiment 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 way.

[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 pre-configured 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 can uniformly increment all SN counters by a predefined offset (e.g., a predefined positive integer, such as 1), thus keeping all SN counters with the same value. Alternatively, the UE can uniformly set all SN counters to a value that was not used to calculate any candidate SN.SN the same random integer. Note that the SN counter wrap-around concept described in Embodiment 1 still applies.

[0112] In some example implementations, the UE employs a single SN counter that covers 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 can increase the SN counter by a predefined offset (e.g., a predefined positive integer, such as 1). Alternatively, the UE can set the SN counter to the random integer that has not yet been used to compute any candidate SN. SN the same random integer. Note that the SN counter wrap-around concept described in Embodiment 1 still applies.

[0113] The above description and the accompanying drawings provide specific examples of embodiments and implementations. However, the described subject matter can be embodied in various and alternative forms, and thus, the claimed subject matter is not limited to any example embodiments described herein. The subject matter is intended to be reasonable broad in scope. Among other things, the subject matter can be embodied as a method, an apparatus, a component, a system, or a non-transitory computer-readable medium storing computer code. Accordingly, for example, embodiments can take the form of hardware, software, firmware, storage media, or any combination thereof. For example, the above-described method embodiments can be implemented by a component, apparatus, or system that includes a memory and a processor by executing computer code stored in the memory.

[0114] Throughout the specification and claims, terms can have subtly different connotations suggested or implied in context beyond the explicitly stated meaning. As such, 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 also 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] Generally, terminology can be understood at least in part from an understanding of how various terminology is used throughout specification and attached claims. For example, terms such as "and", "or", or "and / or" as used herein can include a variety of meanings that can depend at least in part upon the context in which such terms are used. Typically, "or" if used to associate a list, such as A, B or C, is intended to mean A, B, and C, here used in the inclusive sense, as well as A, B or C, here used in the exclusive sense. In addition, the term "one or more" as used herein can describe any feature, structure, or characteristic in the singular or can describe combinations of features, structures or characteristics, both singular and in combination. Likewise, terms such as "a," "an," or "the" as used herein can be understood to convey a singular usage or to convey a plural usage, depending at least in part on context. Additionally, the term "based on" can be understood as not necessarily intended to convey an exclusive set of factors, but rather can allow for existence of additional factors not necessarily expressly described, again at least in part depending on context.

[0116] Reference throughout this specification to features, advantages, or similar language does not mean that all of those features and advantages in connection with the solution can be achieved in any single implementation. 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 implementation of the solution. Thus, discussions of features and advantages, and similar language, throughout this specification may, but do not necessarily, refer to the same embodiment.

[0117] Furthermore, the described features, advantages, and characteristics of the solution can be combined in any suitable manner in one or more embodiments. One skilled in the relevant art will recognize, in light of the description herein, that the solution can be practiced without one or more of the specific features or advantages of a particular embodiment. In other instances, additional features and advantages can be recognized in certain embodiments that can not be present in all embodiments of the solution.

Claims

1. A method for wireless communication, performed by a wireless device in a wireless network, the method comprising: In response to the execution conditions being met, a target primary / secondary cell (PScell) is selected in the radio access network (RAN), the target PScell ​​being associated with a target secondary node (SN), wherein the target SN is a member of a list of SNs, each SN in the list being associated with an SN counter, and the SN counter associated with each SN in the list being used to calculate a security key for each SN in the list; Determine whether the SN counter associated with the target SN needs to be updated; When it is determined that the SN counter associated with the target SN needs to be updated, a refreshed SN counter value is selected, and the refreshed SN counter value is used to update at least the SN counter associated with the target SN, wherein the refreshed SN counter value is different from any previous SN counter value shared between the wireless device and the 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, the first message including 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 fact that the SN associated with the target PScell ​​is 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 of claim 1, wherein the wireless device has dual connectivity with the RAN, the dual connectivity including a connection between the wireless device and the current PScell.

4. The method of claim 3, wherein the dual connectivity further includes a primary connectivity between the wireless device and the master node.

5. The method of claim 1, wherein the initial value of the SN counter associated with each SN in the SN list is pre-configured 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 pre-configured by the master node to the 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: Update the SN counter associated with each SN in the SN list.

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 counters 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: Select a random integer value as the SN counter value for the refresh.

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

11. The method of claim 10, further comprising: The target SN key is derived based on the refreshed SN counter value; as well as Based on the target SN key, activate the security configuration associated with the target PScell.

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 radio network RAN, the method comprising: The wireless device receives a first message requesting to switch the wireless device from the current PScell ​​to a target PScell. The first message includes a refreshed SN counter value for updating the SN counter, wherein the refreshed SN counter value indicates that the target SN associated with the target PScell ​​is different from the SN associated with the current PScell.

14. The method of claim 13, wherein the wireless device has dual connectivity with the RAN, the dual connectivity including an auxiliary connectivity between the wireless device and the current PScell.

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

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

17. The method of claim 16, further comprising: Receive a third message from the target SN as a response to the second message; as well as A fourth message is sent to the wireless device in response to the first message, the fourth message triggering the wireless device to activate the 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 main 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. An apparatus 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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