Non-access stratum (NAS) security mode command and NAS count mismatch avoidance

Abstract

A method includes transmitting, by a core network entity of a core network of a wireless communication system, a non-access stratum (NAS) security mode command (SMC) message to a user equipment (UE), the NAS SMC message including information about security capabilities of the UE, information for establishing a security context between the UE and the core network, and a first NAS security mode message transaction identifier (ID); receiving, by the core network entity from the UE, a NAS security mode completion message including a second NAS security mode message transaction ID; and generating, by the core network entity, a security key based on a comparison of the first NAS security mode message transaction ID and the second NAS security mode message transaction ID satisfying a condition, where the security key is usable to secure communications between the UE and a device of an access network of the wireless communication system.

Description

Technical Field

[0001] The various example embodiments generally relate to wireless networks, and more specifically to the Non-Access Stratum (NAS) Security Mode Command (SMC) procedure. Background Technology

[0002] Wireless networks offer significant advantages to user mobility. The ability to stay connected while on the move not only benefits users but also contributes to greater efficiency and productivity for society as a whole. As user expectations rise, such as for security, wireless network technology must keep pace. Therefore, there is a continued interest in improving wireless network technology. Summary of the Invention

[0003] As used herein, the term “entity” can refer to different components of an architecture or device in a communications network, such as a network device, network node, network function, or any other device (physical or virtual).

[0004] According to an aspect of this disclosure, a method includes: a core network entity of a core network of a wireless communication system sending a Non-Access Stratum (NAS) Security Mode Command (SMC) message to a user equipment (UE), the NAS SMC message including information about the UE's security capabilities, information for establishing a security context between the UE and the core network, and a first NAS Security Mode Message Transaction Identifier (ID); the core network entity receiving a NAS Security Mode Completion message from the UE including a second NAS Security Mode Message Transaction ID; and the core network entity generating a security key based on a comparison condition satisfying the first NAS Security Mode Message Transaction ID and the second NAS Security Mode Message Transaction ID, wherein the security key can be used to protect communication between the UE and devices of the access network of the wireless communication system.

[0005] In one aspect of this method, the generation of the security key is also based on the matching between the second NAS security mode message transaction ID in the NAS security mode completion message and the first NAS security mode message transaction ID in the NAS SMC message.

[0006] In one aspect of the method, the first NAS security mode message transaction ID in the NAS SMC message includes a first NAS ID specific to the transmission of the NAS SMC message, and the second NAS security mode message transaction ID in the NAS security mode completion message includes a second NAS ID.

[0007] In one aspect of the method, the first NAS security mode message transaction ID in the NAS SMC message includes a first bitmap, the first bitmap including an indication of the number of retransmissions of the NAS SMC message, and the second NAS security mode message transaction ID in the NAS security mode completion message includes a second bitmap.

[0008] In one aspect of this method, the first NAS security mode message transaction ID in the NAS SMC message corresponds to the NAS downlink message sequence number, and the second NAS security mode message transaction ID in the NAS security mode completion message corresponds to the NAS uplink message sequence number.

[0009] In one aspect of this method, NAS SMC messages are sent based on the expiration of the retransmission timer.

[0010] In one aspect of the method, the method further includes generating a first NAS security mode message transaction ID by a core network entity based on the expiration of a retransmission timer.

[0011] In one aspect of the method, the method further includes: receiving from the UE a third NAS security mode message completion message including a third NAS security mode message transaction ID by a core network entity; and, based on the fact that the comparison between the first NAS security mode message transaction ID and the third NAS security mode message transaction ID fails to meet the condition, continuing to monitor the NAS security mode completion message by the core network entity without generating a security key.

[0012] In one aspect of the method, the method further includes: if the comparison between the first NAS security mode message transaction ID and the third NAS security mode message transaction ID fails to meet the condition, the core network entity maintains a retransmission timer.

[0013] In one aspect of the method, the method further includes receiving a registration request message from the UE by a core network entity, the registration request message including an indication of whether the UE supports NAS security mode message transaction identifiers.

[0014] According to an aspect of this disclosure, a method includes: receiving a Non-Access Stratum (NAS) Security Mode Command (SMC) message from a core network entity of a core network of a wireless communication system, the NAS SMC message including information about the UE's security capabilities, integrity key information, and a first NAS Security Mode Message Transaction Identifier (ID); generating a second NAS Security Mode Message Transaction ID based on the first NAS Security Mode Message Transaction ID; and sending a NAS Security Mode Completion message including the second NAS Security Mode Message Transaction ID to the core network entity.

[0015] In one aspect of this method, the first NAS security mode message transaction ID in the NAS SMC message includes the NAS ID specific to the transmission of the NAS SMC message.

[0016] In one aspect of the method, generating the second NAS security mode message transaction ID includes setting the second NAS security mode message transaction ID by the UE based on the NAS ID in the NAS SMC message.

[0017] In one aspect of this method, the first NAS security mode message transaction ID in the NAS SMC message includes an indication of the number of retransmissions associated with the NASSMC message.

[0018] In one aspect of the method, generating the second NAS security mode message transaction ID includes setting the second NAS security mode message transaction ID by the UE based on the number of retransmissions associated with the NAS SMC message.

[0019] In one aspect of the method, the method further includes the UE sending a registration request message to the core network entity, the registration request message including an indication of whether the UE supports NAS security mode message transaction identifiers.

[0020] The independent claims provide the subject matter for several aspects. The dependent claims define several additional aspects. Attached Figure Description

[0021] Some exemplary embodiments will now be described with reference to the accompanying drawings.

[0022] Figure 1 This is a diagram of an example embodiment of wireless networking between a network system and a user equipment (UE) according to an illustrative aspect of this disclosure;

[0023] Figure 2 This is a diagram illustrating an example component of a network system according to an aspect of this disclosure;

[0024] Figure 3 This is a diagram illustrating an example embodiment of the operation of a NAS Security Mode Command (SMC) procedure according to one aspect of this disclosure;

[0025] Figure 4 This is a diagram of an example embodiment of the operation of the uplink and downlink NAS count increment process according to an illustrative aspect of this disclosure;

[0026] Figure 5 This is a diagram illustrating an example of a security key misalignment scenario according to one aspect of this disclosure;

[0027] Figure 6This is a diagram of an example embodiment of the operation of a NAS SMC process according to an aspect of this disclosure, which supports avoiding mismatches between the NAS SMC and associated NAS counts between the UE and the network;

[0028] Figure 7 This is a diagram of an example embodiment of a NAS security mode message transaction identifier according to an illustrative aspect of this disclosure;

[0029] Figure 8 This is a diagram of an example embodiment of the operation of a NAS SMC process according to an aspect of this disclosure, which supports avoiding mismatches between the NAS SMC and associated NAS counts between the UE and the network;

[0030] Figure 9 This is a diagram of an example embodiment of the operation of a NAS SMC process according to an aspect of this disclosure, which supports avoiding mismatches between the NAS SMC and associated NAS counts between the UE and the network;

[0031] Figure 10 This is a diagram of an example embodiment of the operation of a NAS SMC process according to an aspect of this disclosure, which supports avoiding mismatches between the NAS SMC and associated NAS counts between the UE and the network;

[0032] Figure 11 This is a diagram of an example embodiment of the operation of a NAS SMC process according to an aspect of this disclosure, which supports avoiding mismatches between the NAS SMC and associated NAS counts between the UE and the network;

[0033] Figure 12 This is a flowchart illustrating an example operation of a network device performing a NAS SMC process according to an aspect of this disclosure;

[0034] Figure 13 This is a flowchart illustrating an example operation of a UE performing a NAS SMC procedure according to one aspect of this disclosure; and

[0035] Figure 14 This is a diagram illustrating an example embodiment of a component of a UE or network device according to one aspect of this disclosure. Detailed Implementation

[0036] In the following description, certain specific details are set forth in order to provide a thorough understanding of the disclosed aspects. However, those skilled in the art will recognize that the aspects can be practiced without one or more of these specific details or using other methods, components, materials, etc. In other instances, well-known structures associated with transmitters, receivers, or transceivers are not shown or described in detail to avoid unnecessarily obscuring the description of the aspects.

[0037] In this specification, references to "one aspect" or "an aspect" indicate that a particular feature, structure, or characteristic described in conjunction with that aspect is included in at least one aspect. Therefore, the appearance of the phrases "in one aspect" or "in an aspect" in various places within this specification does not necessarily refer to the same aspect. Furthermore, a particular feature, structure, or characteristic may be combined in any suitable manner with one or more aspects.

[0038] The embodiments described in this disclosure can be implemented in wireless network devices, such as, but not limited to, devices utilizing: Global Microwave Access Interoperability (WiMAX), Global System for Mobile Communications (GSM, 2G), GSM EDGE Radio Access Network (GERAN), General Packet Radio Service (GRPS), Universal Mobile Telecommunications System based on Basic Wideband Code Division Multiple Access (W-CDMA) (UMTS, 3G), High-Speed ​​Packet Access (HSPA), Long Term Evolution (LTE), Advanced LTE, Enhanced LTE (eLTE), 5G New Radio (5G NR), Advanced 5G, 6G (and higher), and other wireless network systems such as 802.11ax (Wi-Fi 6). The term "eLTE" here refers to LTE evolution connected to a 5G core. LTE is also known as Evolved UMTS Terrestrial Radio Access (EUTRA) or Evolved UMTS Terrestrial Radio Access Network (EUTRAN).

[0039] Wireless communication systems can include a Non-Access Stratum (NAS) and an Access Stratum (AS). NAS is the protocol between the User Equipment (UE) and the core network of the wireless communication system. The NAS protocol can provide various functions, such as, but not limited to, supporting service and signaling messages between the core network and the UE, managing the establishment of communication sessions, and maintaining continuous communication with the UE when it moves to different areas. AS is the protocol between the UE and the access network of the wireless communication system. The AS protocol can provide radio access or an air interface for radio communication between the UE and the access network. Security is an important aspect of wireless communication. The security keys used for NAS and AS protection can depend on the specific security algorithms used. NAS and AS security keys are derived at the core network and UE from security key parameters generated during the NAS-level authentication and key negotiation (AKA) process.

[0040] In 3GPP wireless communication systems, the NAS Security Mode Command (SMC) procedure can be used to establish a NAS security context between the UE and a core network entity (e.g., Access and Mobility Management (AMF)) of the wireless communication system's core network. The NAS security context may include, but is not limited to, security keys (e.g., AMF keys (K...)). AMF This includes encryption algorithms, integrity algorithms, and a set of security parameters (e.g., NAS count, NAS integrity key, NAS encryption key). The NASSMC procedure may include message round trips between the AMF and the UE, as described, for example, in Section 6.7.2 of 3GPP Technical Document TS 33.501 V18.2.0 (2023-06) (“TS 33.501 document”) (the entire contents of which are incorporated herein by reference). For example, the AMF may send a NAS SMC message to the UE, and the UE may respond using NAS security mode completion.

[0041] A UE can initiate registration with the core network by sending a registration request via the access network. In the example, the UE can include information about its security capabilities in the registration request. For instance, the registration request may include one or more Information Elements (IEs) indicating the UE's security capabilities. The NAS SMC procedure is designed to protect the registration request from man-in-the-middle attacks, in which an attacker modifies the IEs indicating the UE's security capabilities. If the NAS SMC procedure completes successfully, the UE attaches to the core network knowing that no suppression attack has occurred. If a suppression attack is attempted, the NAS SMC verification may fail, and the UE may respond with a rejection message, indicating that the UE may be unable to attach to the core network.

[0042] As part of the NAS SMC procedure, the AMF and UE can independently maintain and track two separate NAS counters: the uplink NAS count and the downlink NAS count. At the start of the NAS SMC procedure, the downlink NAS count and the uplink NAS count can be set to the same value (e.g., 0). The AMF can increment its local downlink NAS count for each transmitted NAS SMC message, and the UE can increment its local downlink NAS count for each received NAS SMC message that successfully passes the NAS security check. Similarly, the UE can increment its local uplink NAS count for each transmitted NAS security mode completion message, and the AMF can increment its local uplink NAS count for each received NAS security mode completion message that successfully passes the NAS security check. Furthermore, the AMF can use its current downlink NAS count to generate a message sequence number to be included in the NAS SMC message (for transmission to the UE). Likewise, the UE can use its current uplink NAS count to generate a sequence number to be included in the NAS security mode completion message (for transmission to the AMF). In one example, the NAS count value can be a 24-bit value, and the corresponding sequence number can correspond to the lowest 8 bits of the NAS count value.

[0043] At the end of a successful NAS SMC process, each of the AMF and UE can generate a security key individually (e.g., the gNB key (K)). gNBThis is used to protect AS communication between the UE and the access node (e.g., a base station). For this purpose, the AMF can generate a security key based on the NAS count associated with a NAS security mode completion message received from the UE (e.g., using the NAS count as input to a key derivation function (KDF)). The AMF can send the generated security key to the base station. Similarly, after the UE sends a NAS security mode completion message to the AMF, the UE can generate a security key based on the NAS count associated with the sent NAS security mode completion message (e.g., using the NAS count as input to the same KDF as the AMF). The base station can utilize the security key generated by the AMF, and the UE can utilize the security key generated by the UE for AS communication between them (e.g., performing an AS SMC procedure). For example, the base station can send a message generated under security protection using the security key generated by the AMF (e.g., an AS SMC message), and the UE can receive the message and verify the received message using the generated UE-generated security key. Under normal operating conditions, NAS SMC messages from the AMF can successfully reach the UE, and the corresponding response (NAS Security Mode Completion Message) can successfully reach the AMF. Therefore, the AMF and the UE can each generate a security key (e.g., K) for AS communication based on the NAS count from the same NAS Security Mode Completion Message. gNB ).

[0044] As used herein, unless otherwise stated, the terms “network system,” “network side,” and “network” (when used alone) may include both access network components and core network components.

[0045] Section 5.4 of 3GPP Technical Document TS 24.501 V18.3.1 (2023-06) (“TS 24.501 document”) (the entire contents of which are incorporated herein by reference) specifies the handling of various abnormal situations that can occur on the network side during the NAS SMC process. TS 24.501 document specifies the use of retransmission timers for the AMF. More specifically, the AMF can start a retransmission timer (e.g., referred to as timer T3560) after sending a NASSMC message to the UE. The AMF can retransmit the NAS SMC message on the first expiration of timer T3560, and can reset and restart timer T3560. This retransmission can be repeated four times. That is, the NAS SMC process will be aborted on the fifth expiration of timer T3560. The AMF can stop timer T3560 upon receiving a NAS safe mode complete message.

[0046] In certain situations, there may be a delay in the UE's response to the initial NAS SMC message sent by the AMF (e.g., due to unstable conditions in the radio interface). For example, the NAS security mode completion message sent by the UE in response to the initial NAS SMC message may arrive at the AMF after the AMF has retransmitted the NAS SMC message (due to the expiration of the T3560 timer). Meanwhile, the UE can successfully process the retransmitted NAS SMC message. As will be discussed more fully below, this situation may cause the UE to generate a security key (e.g., K) based on the uplink NAS count value associated with the UE's response to the retransmitted NAS SMC message. gNB The AMF generates a security key (e.g., K) based on the uplink NAS count value associated with the UE's response to the initially sent NAS SMC message. gNB In other words, regarding key generation, there is a mismatch between the NAS SMC and related NAS counts between the UE and the AMF. Therefore, the security key generated by the UE (e.g., K) gNB ) and the security key generated by AMF (e.g., K) gNB The different security keys can lead to a mismatch or misalignment of the security keys between the AMF and the UE. As mentioned above, the AMF transmits the security key it generates to the corresponding base station for subsequent AS communication with the UE (e.g., AS SMC procedure). However, due to the security key mismatch, the UE may fail to verify the AS communication received from the base station.

[0047] This disclosure provides techniques for performing NAS SMC procedures that support avoiding mismatches between the UE and the network in NAS SMC and related NAS counts. For example, a message transaction identifier (ID) (e.g., an append message field) can be added to the downlink NAS SMC message and the uplink NAS security mode completion message during the NAS SMC procedure. The network (e.g., AMF) can send a NAS SMC message with a NAS security mode message transaction ID. The NAS security mode message transaction ID can identify a specific transmission of the NAS SMC message. In other words, the initially sent NAS SMC message and each subsequent retransmitted NAS SMC message(s) can include different NAS security mode message transaction IDs. When the UE responds to a NAS SMC message, the UE can send a NAS security mode completion message with the same NAS security mode message transaction ID as the received NAS SMC message. When the AMF receives the NAS security mode completion message, if the NAS security mode message transaction ID in the NAS security mode completion message matches the NAS security mode message transaction ID in the most recently sent NAS SMC message, the AMF can generate a security key (e.g., K). gNB Otherwise, the AMF will send a new retransmission message (NASSMC message).

[0048] According to one aspect of this disclosure, a core network entity (e.g., AMF) of the core network of a wireless communication system can send a NAS SMC message including a first NAS security mode message transaction ID to a UE. The NAS SMC message may also include information about the UE's security capabilities (e.g., playback of UE security capabilities) and information for establishing a security context between the UE and the core network (e.g., key set identifier (ngKSI), encryption algorithm, integrity algorithm, message authentication code integrity (MAC-I)). The core network entity can receive a NAS security mode completion message including a second NAS security mode message transaction ID from the UE. Based on a comparison condition satisfying the first and second NAS security mode message transaction IDs, the core network entity can generate a security key (e.g., K...). gNB The security key can be used to protect AS communication between the UE and access network devices (e.g., base stations) of the wireless communication system. In some aspects, generating the security key can also be based on a match between the second NAS security mode message transaction ID in the NAS security mode completion message and the second NAS security mode message transaction ID in the NAS SMC message. For example, when the comparison result is a match, the core network entity can use the uplink NAS count associated with the received NAS security mode completion message as input to the KDF to generate the security key.

[0049] In some respects, the first NAS security mode message transaction ID in the NAS SMC message may include a first NAS ID specific to the transmission of the NAS SMC message. The second NAS security mode message transaction ID in the NAS security mode completion message may include a second NAS ID, wherein the NAS security mode completion message may be a response to a NAS SMC message associated with the second NAS ID. For example, the core network entity may generate a new (or unique) NAS ID for each NAS SMC message to be sent to the UE, and when the UE responds to a received NAS SMC message, the UE may set the NAS ID in the NAS security mode completion message to be sent to the core network entity based on the NAS ID in the received NAS SMC message.

[0050] In some respects, the first NAS security mode message transaction ID in a NAS SMC message may include a first bitmap, which includes an indication of the number of retransmissions of the NAS SMC message (e.g., 0, 1, 2, 3, or more). The second NAS security mode message transaction ID in a NAS security mode completion message may include a second bitmap, where the NAS security mode completion message may be a response to a NAS SMC message associated with the second bitmap. For example, for each NAS SMC message to be sent by a core network entity, the core network entity may set the bitmap in the NAS SMC message to a value corresponding to the number of transmissions of the NAS SMC message. For example, a value of 0 may indicate an initial transmission, a value of 1 may indicate a first retransmission, a value of 2 may indicate a second retransmission, and so on. When a UE responds to a received NAS SMC message, the UE may set the bitmap in the NAS security mode completion message to be sent to the core network entity based on the bitmap in the received NAS SMC message.

[0051] In some respects, sending NAS SMC messages can also be based on the expiration of a retransmission timer (e.g., the T3560 timer). In some respects, core network entities can also generate the first NAS security mode message transaction ID based on the expiration of a retransmission timer.

[0052] In some respects, the core network entity can also receive another NAS security mode completion message from the UE, including the transaction ID of the third NAS security mode message. The core network entity can continue monitoring the NAS security mode completion message without generating a security key (e.g., K) if the comparison between the first and third NAS security mode message transaction IDs fails to meet a condition. gNBIn other words, the core network entity can avoid generating a security key when the comparison fails. In some respects, the core network entity can also maintain a retransmission timer (e.g., a T3560 timer) based on the failure of a comparison between the first NAS security mode message transaction ID and the third NAS security mode message transaction ID. That is, the core network entity can avoid stopping the retransmission timer when the comparison fails.

[0053] In some respects, the core network entity can also receive a registration request message from the UE, which includes an indication of whether the UE supports the NAS security mode message transaction identifier. For example, based on the UE's support for the NAS security mode message transaction identifier, the core network entity can use the NAS security mode message transaction ID as described above to determine whether a security key (e.g., K) should be generated. gNB ).

[0054] For backward compatibility, this means that when the UE does not support the NAS security mode message transaction identifier, the core network entity can generate a security key (e.g., K). gNB Previously, similar comparisons were performed using NAS message sequence numbers. For example, the first NAS security mode message transaction ID in the NAS SMC message could correspond to the NAS downlink message sequence number, and the second NAS security mode message transaction ID in the NAS security mode completion message could correspond to the NAS uplink message sequence number. Furthermore, if the NAS uplink message sequence number in the received NAS security mode completion message matches the NAS downlink message sequence number in the sent NAS SMC message, the core network entity could generate a security key. These and other aspects will be described in more detail later in this document.

[0055] This disclosure offers several benefits. For example, adding the NAS security mode message transaction ID to the NASSMC message (sent by the AMF) and the NAS security mode completion message (sent by the UE) ensures that the AMF generates or calculates the security key (e.g., K). gNB Before that, it waits for a response (NAS Security Mode Complete Message) to the last retransmitted NAS SMC message. In this way, the security key generated by the AMF can be matched with the security key generated by the UE, thus avoiding the aforementioned NAS SMC mismatch and key misalignment issues. The alternative mechanism of reusing NAS message sequence numbers ensures that the AMF generates or calculates the security key (e.g., K...) in a timely manner. gNBBefore waiting for a response (NAS Secure Mode Complete message) to the last retransmitted NAS SMC message, the aforementioned NAS SMC mismatch and key misalignment issues are avoided without modifying the NAS SMC message structure and the NAS Secure Mode Complete message structure. Although this disclosure is described in the context of a NAS SMC procedure, it applies to any NAS procedure that utilizes round-trip messages and retransmissions.

[0056] This disclosure may use the term "serving network device" to refer to a network node or network device (or part thereof) serving a UE. As used herein, the terms "send to," "receive from," and "cooperate with" (and variations thereof) include communication that may or may not involve communication via one or more intermediate devices or nodes. The term "acquire" (and variations thereof) includes initial acquisition or acquisition following initial acquisition. The term "connection" may refer to a physical connection or a logical connection.

[0057] This disclosure uses 5G NR as an example of a wireless network, and may use smartphones and / or unmanned aerial vehicles as examples of UEs. It should be understood that such examples are merely illustrative, and this disclosure applies to other wireless networks and user equipment.

[0058] Figure 1 This is a diagram illustrating an example of wireless networking between network system 100 and user equipment (UE) 150. Network system 100 may include one or more network nodes 120, one or more servers 110, and / or one or more network devices 130 (e.g., test equipment). Network node 120 will be described in more detail below. As used herein, the term "network apparatus" can refer to any component of network system 100, such as server 110, network node 120, network device 130, any(multiple) components of the foregoing, and / or any(multiple) other components of network system 100. Examples of network apparatus include, but are not limited to, apparatuses for implementing various aspects of 5G NR. This disclosure describes embodiments related to 5G NR and embodiments relating to aspects defined by 3GPP. However, it is contemplated that embodiments related to other wireless network technologies are also covered within the scope of this disclosure.

[0059] The following description provides further details of examples of network nodes. In a 5G NR network, a gNodeB (also known as a gNB) may include, for example, nodes that provide NR user plane and control plane protocol termination toward the UE and are connected to the 5G core (5GC) via a next-generation (NG) interface, such as according to Section 3.2 of 3GPP TS 38.300 V16.6.0 (2021-06) (the entire contents of which are incorporated herein by reference).

[0060] gNB supports various protocol layers, such as Layer 1 (L1) (i.e., the physical layer), Layer 2 (L2), and Layer 3 (L3).

[0061] NR's Layer 2 (L2) is divided into the following sublayers: Media Access Control (MAC), Radio Link Control (RLC), Packet Data Convergence Protocol (PDCP), and Service Data Adaptation Protocol (SDAP), among which, for example: ○ The physical layer provides a transmission channel to the MAC sublayer; ○ The MAC sublayer provides logical channels to the RLC sublayer; ○ The RLC sublayer provides RLC channels to the PDCP sublayer; ○ The PDCP sublayer provides radio bearers to the SDAP sublayer; ○ The SDAP sublayer provides Quality of Service (QoS) flows to 5GC; ○ The control channels include the Broadcast Control Channel (BCCH) and the Physical Control Channel (PCCH).

[0062] Layer 3 (L3) includes, for example, Radio Resource Control (RRC) conforming to Section 6 of 3GPP TS 38.300 V16.6.0 (2021-06) (the entire contents of which are incorporated herein by reference).

[0063] The gNB Central Unit (gNB-CU) includes, for example, a logical node that hosts the gNB's RRC, SDAP, and PDCP protocols, or the en-gNB's RRC and PDCP protocols, and controls the operation of one or more gNB Distributed Units (gNB-DUs). The gNB-CU terminates the F1 interface connected to the gNB-DU. The gNB-CU may also be referred to herein as a CU, Central Unit, Centralized Unit, or Control Unit.

[0064] A gNB Distributed Unit (gNB-DU) includes, for example, a logical node that hosts the RLC, Media Access Control (MAC), and Physical (PHY) layers of the gNB or en-gNB, and its operation is partially controlled by the gNB-CU. A gNB-DU supports one or more cells. A cell is supported by only one gNB-DU. The gNB-DU terminates the F1 interface connected to the gNB-CU. The gNB-DU may also be referred to herein as a DU or Distributed Unit.

[0065] As used herein, the term "network node" may refer to any gNB, gNB-CU, or gNB-DU, or any combination thereof. RAN (Radio Access Network) nodes or network nodes (such as, for example, gNB, gNB-CU, or gNB-DU, or portions thereof) may be implemented using means, for example, having at least one processor and / or at least one memory having processor-readable instructions ("program") configured to support and / or supply and / or process CU and / or DU related functions and / or features, and / or at least one protocol (sub) layer of the RAN (Radio Access Network), such as layer 2 and / or layer 3. Different functional divisions may exist between the central unit and the distributed units. The following will combine... Figure 14 Examples describing such devices and components.

[0066] The gNB-CU and gNB-DU portions can be co-located or physically separated. The gNB-DU can even be further divided into two parts, for example, one part including processing equipment and the other including antennas. The Central Unit (CU) can also be referred to as a Baseband Unit / Radio Equipment Controller / Cloud RAN / Virtual RAN (BBU / REC / C-RAN / V-RAN), Open RAN (O-RAN), or a portion thereof. The Distributed Unit (DU) can also be referred to as a Remote Radio Head / Remote Radio Unit / Radio Equipment / Radio Unit (RRH / RRU / RE / RU), or a portion thereof. In the various exemplary embodiments of this disclosure, a network node supporting at least one of the Central Unit functions or Layer 3 protocols of a radio access network can be, for example, a gNB-CU. Similarly, a network node supporting at least one of the Distributed Unit functions or Layer 2 protocols of a radio access network can also be, for example, a gNB-DU.

[0067] A gNB-CU can support one or more gNB-DUs. A gNB-DU can support one or more cells, and therefore can support the serving cell for a user equipment (UE), or candidate cells for other procedures such as handover, dual connectivity, and / or carrier aggregation.

[0068] UE 150 may be or include wireless or mobile devices, devices having a radio interface for interacting with the RAN (Radio Access Network), smartphones, in-vehicle devices, Internet of Things (IoT) devices, or machine-to-machine (M2M) devices, and other types of user equipment. Such a UE 150 may include: at least one processor; and at least one memory including program code; wherein the at least one memory and the computer program code are configured, together with the at least one processor, to cause the device to perform at least certain operations, such as, for example, an RRC connection with the RAN. Examples of UE components will be combined. Figure 9The following description is provided. In an embodiment, UE 150 may be configured to generate messages (e.g., including a cell ID) to be transmitted via radio to the RAN (e.g., to reach and communicate with the serving cell). In an embodiment, UE 150 may generate, transmit, and receive RRC messages containing one or more RRC PDUs (Packet Data Units). Those skilled in the art will understand the RRC protocol and other processes that the UE may perform.

[0069] Continue to refer to Figure 1 In an example of a 5G NR network, network system 100 provides one or more cells that define the coverage area of ​​network system 100. As described above, network system 100 may include a gNB of the 5G NR network, or may include any other means configured to control radio communications and manage radio resources within the cell. As used herein, the term "resource" may refer to radio resources such as resource blocks (RBs), physical resource blocks (PRBs), radio frames, subframes, time slots, subbands, frequency regions, subcarriers, beams, etc. In embodiments, network node 120 may be referred to as a base station.

[0070] Figure 1 An example is provided and is only for illustrative purposes regarding network system 100 and UE 150. Those skilled in the art will understand that network system 100 includes... Figure 1 Components not shown in the diagram, and it will be understood that other user devices can communicate with network system 100.

[0071] Figure 2 yes Figure 1 A block diagram of example components of network system 100. A 5G NR network can be described as an example of network system 100, and the aspects described below should also apply to other types of network systems. The network system can be configured according to... Figure 1 The signals and connections shown operate to enable UE 150 to communicate with network system 100 via RAN 225. Furthermore, as shown and described herein, the network system can be divided into user plane components and functions, and control plane components and functions. Unless otherwise stated, the terms “component,” “function,” and “service” are used interchangeably herein, and they can refer to instructions executed by and implemented by one or more processors.

[0072] The following describes example functionality of these components. This example functionality is illustrative only, and it should be understood that the components described herein can perform additional operations and functions. Furthermore, connections between components can be virtual connections via service-based interfaces, allowing any component to communicate with any other component. In this way, any component can act as a service "producer" for any other component as a service "consumer," providing services for network functions.

[0073] For example, a control network (CN) 210 is described in the control plane of the network system. CN 210 includes an Authentication Server Function (AUSF) 211, an AMF 212, and a Session Management Function (SMF) 213. CN 210 also includes a Network Slice Selection Function (NSSF) 214, a NEF 215, a Network Repository Function (NRF) 216, and a UDM 217, which may include a UDR 224.

[0074] The additional components and functions of CN 210 include application function (AF) 218 ​​and PCF 219.

[0075] The user plane includes UE 150, Radio Access Network (RAN) 225, User Plane Function (UPF) 226, and Data Network (DN) 227. RAN 225 may include a combination of Figure 1 The RAN 225 describes one or more components, such as one or more network nodes. However, the RAN 225 may not be limited to such components. The UPF 226 provides connectivity for data transmitted through the RAN 225. For example, the DN 227 identifies services from service providers, internet access, and third-party services.

[0076] AMF 212 handles connectivity and mobility tasks. AUSF 211 receives authentication requests from AMF 212 and interacts with UDM 217 to authenticate and verify network responses, responsible for determining successful authentication. SMF 213 performs PDU session management and manages the session context with UPF 226.

[0077] NSSF 214 can select a Network Slice Instance (NSI) and determine the allowed Network Slice Selection Auxiliary Information (NSSAI). This selection and determination are used to configure AMF 212 to provide services to UE 150. NEF 215 ensures third-party access to network services to create dedicated network services. NRF 216 acts as a repository for storing network functions, allowing these functions to register and discover each other.

[0078] UDM 217 generates authentication vectors for use by AUSF 211 and AMF 212 and provides user identity processing. UDM 217 can connect to UDR 224, which stores data associated with authentication, applications, etc. AF 218 provides application services (e.g., streaming services) to users. PCF 219 provides policy control functions. For example, PCF 219 can assist with network slicing and mobility management, and provide QoS and accounting functions. In some cases, UDM 217 and / or UDR 224 can be referred to as network data components.

[0079] In some examples, AMF 212 can perform a NAS SMC procedure with UE 150. According to aspects of this disclosure, AMF 212 can send a NAS SMC message to UE 150 including a first NAS security mode message transaction ID. The NAS SMC message may also include information about the security capabilities of UE 150 (e.g., replay of UE 150's security capabilities) and information for establishing a security context between UE 150 and the core network (e.g., key set identifier (ngKSI), encryption algorithm, integrity algorithm, NAS message authentication code). AMF 212 can receive a NAS security mode completion message from UE 150 including a second NAS security mode message transaction ID. Based on a comparison condition satisfying the first and second NAS security mode message transaction IDs, AMF 212 can generate a security key (e.g., K...). gNB The security key is used to protect AS communication between UE 150 and RAN 225. The mechanism used to perform the NAS SMC procedure will be discussed in more detail below. This mechanism supports the avoidance of NAS SMC mismatches and related NAS counts at both the UE and network levels in order to generate the security key.

[0080] Figure 2 These are merely examples of components of a network system, and variations are considered to be within the scope of this disclosure. In embodiments, the network system may include... Figure 2 Other components not shown in the diagram. In an embodiment, the network system may not include... Figure 2 Each component is shown. In an embodiment, components and connections can be used with... Figure 2 The connections shown are implemented using different connections. Such and other embodiments are considered to be within the scope of this disclosure.

[0081] Figure 3 This is a diagram illustrating an example embodiment of the operation of a NAS SMC process according to an aspect of this disclosure. It should be understood that the described signals may have associated operations, and the described operations may have associated signals. Therefore, the described signals may also relate to operations, and the described operations may also relate to signals. Furthermore, Figure 3 This will describe the signals between various network components and the operations performed by these components, such as... Figure 3 Those shown at the top. Specifically, these components include the UE (e.g., Figure 1 UE 150) and wireless communication systems (e.g., Figure 1 and Figure 2 The core network's AMF (e.g., network system) of the network system) Figure 2(AMF 212). The network components are illustrative, and it is conceivable that other components may be involved in the signals, or that other components may perform operations. In some examples, each network component may use a signal with, for example, AMF 212. Figure 14 The apparatus of the components shown is used to implement the operation. One or more of the following operations can be implemented in conjunction with the operations of this disclosure, such as those referenced above. Figures 1-2 Examples of discussion.

[0082] Figure 3 The NAS SMC procedure shown can be used to establish a NAS security context between the UE and the AMF. This procedure can include message round trips between the AMF and the UE. The AMF can send a NAS SMC message to the UE, and the UE can respond to the message using the NAS security mode.

[0083] The NAS SMC procedure is designed to protect registration requests from man-in-the-middle attacks, in which an attacker modifies the IE (Information Interface) in the registration request that indicates the UE's security capabilities. If the NAS SMC procedure completes successfully, the UE attaches to the core network knowing that no suppression attack has occurred. If a suppression attack is attempted, the NAS SMC authentication may fail, and the UE may respond with a denial message, indicating that the UE may be unable to attach to the core network.

[0084] like Figure 3 As shown in operation 301a, the AMF initiates (or activates) NAS integrity protection before sending a NAS SMC message to the UE. Activation may include configuring and / or activating the functions used to perform NAS integrity protection.

[0085] In Operation 301b, the AMF sends a NAS SMC message and the UE receives it. The NAS SMC message may include UE security capabilities and information used to establish a security context (UE security context) between the UE and the AMF. The UE security capabilities may be a replay of the UE security capabilities received by the AMF during the registration request. The information used to establish the security context may include, for example, but not limited to, the selected NAS integrity algorithm and information for identifying K. AMF The ngKSI. NAS SMC message can also include K_AMF_change_flag (e.g., carried in the specified additional 5G security parameter IE as described in the TS 24.501 document) to indicate the new K. AMF The NAS SMC message may also include a flag requesting a complete initial NAS message (sent to the AMF during the initial registration request) and inter-architecture anti-suppression (ABBA) parameters. This is performed during mobility registration updates or during multiple registrations within the same Public Land Mobile Network (PLMN) for K. AMFIn the case of leveling, K_AMF_change_flag can be included in the NAS SMC message, for example, as described in section 6.9.3 of TS 24.501 document. The NASSMC message can be based on the K_AMF_change_flag indicated by ngKSI in the NAS SMC message. AMF Integrity protection (but not encryption) is performed using a NAS integrity key. For example, NAS SMC messages may also include a NAS message authentication code (NAS-MAC) calculated based on the NAS integrity key and the NAS integrity algorithm. In some cases, NAS-MAC may also be referred to as MAC-I, as described in Annex D.3 of TS 33.501 document.

[0086] If the network supports interaction via the N26 interface between the Mobility Management Entity (MME) and the AMF (e.g., between the 5G core and the Evolved Packet Core (EPC), the AMF can also include the selected Evolved Packet System (EPS) NAS algorithm in the NAS SMC message for use after mobility to EPS. The UE can store the algorithm using the N26 interface between the MME and AMF for use after mobility to EPS. The AMF can store the selected EPS NAS algorithm in the UE security context.

[0087] When the AMF changes due to N2 handover or idle mode mobility, the selected EPS NAS algorithm can be included in the 5G UE security context and provided to the target AMF as part of the 5G UE security context. Those skilled in the art will understand N2 handover.

[0088] In Operation 301c, the AMF initiates (or activates) NAS uplink decryption after sending the NAS SMC message. Activation may include configuring and / or activating the NAS uplink decryption functionality.

[0089] In Operation 302a, the UE verifies the NAS SMC message. For example, the UE can check whether the UE security capabilities sent by the AMF match the UE security capabilities stored in the UE to ensure that these UE security capabilities cannot be modified by an attacker. The UE can also verify the K based on the indicated ngKSI. AMFThe UE uses the indicated NAS integrity algorithm and NAS integrity key to verify the integrity protection of the NASSMC message. For example, the UE can calculate the NAS-MAC based on the NAS integrity algorithm and NAS integrity key, and verify the calculated expected NAS-MAC (XNAS-MAC) against the NAS-MAC included in the received NAS SMC message. If the integrity verification of the NAS SMC message is successful, the UE can use the security context indicated by ngKSI to begin NAS integrity protection, encryption, and / or decryption of the NAS message.

[0090] If the NAS SMC message includes K_AMF_change_flag, the UE can derive the new K as described in Annex A.13 of TS 33.501 document. AMF And set the NAS count (e.g., the local uplink and downlink NAS counts at the UE) to zero. See below for reference. Figure 4 A more comprehensive discussion of the mechanisms used to maintain and track NAS counts.

[0091] In operation 302b, based on the successful verification at operation 302a, the UE sends a NAS Security Mode Completion Message and the AMF receives the NAS Security Mode Completion Message (to confirm the successful completion of the NAS SMC). The sent NAS Security Mode Completion Message can be encrypted and protected for integrity (based on the security context). The NAS Security Mode Completion Message may include a Permanent Device Identifier (PEI) in case the AMF requests the PEI in the NAS SMC message. If K AMF If the level is determined to be executed, the AMF can set the NAS count (e.g., the local uplink and downlink NAS counts at the AMF) to zero. In one example, the UE can include a complete initial NAS message sent to the AMF during the initial registration request in the NAS secure mode completion message. The initial NAS message is the first message sent to the AMF after the UE transitions from an idle state, for example, as described in Section 6.4.6 of TS 33.501 document.

[0092] However, if the verification of the NAS SMC message at operation 302a fails at the UE, the UE can respond using a NAS security mode rejection message (see TS 24.501 document). The NAS security mode rejection message and all subsequent NAS messages can be protected with the previous 5G NAS security context (if any) (i.e., the 5G NAS security context used before the failed NAS SMC message). If no 5G NAS security context exists before the NAS SMC message, the NAS security mode rejection message may still remain unprotected.

[0093] In Operation 301c, the AMF uses the keys and algorithms indicated in the NAS SMC message to decrypt and check the integrity protection of the NAS secure mode completion message. If the integrity protection check passes and the AMF successfully decrypts the NAS secure mode completion message, a security context is established for the UE. In the example, the security context may include the indicated ngKSI, the K identified from the ngKSI, and so on. AMF UE security capabilities, AMF uplink and downlink NAS counts.

[0094] In Operation 301d, after successfully receiving (e.g., including decryption and checking integrity protection) the NAS security mode completion message, the AMF can use the established security context to begin NAS downlink encryption.

[0095] The following will be a reference Figure 4 More comprehensively, as part of the NAS SMC procedure, the AMF and UE can independently maintain and track downlink NAS counts and uplink NAS counts. For example, for each transmitted NAS message, the UE can increment its local uplink NAS count (e.g., a 24-bit value). In some examples, if the UE determines that the uplink NAS count graph has wrapped around after sending a NAS secure mode complete message at Operation 302b, the UE can send a NAS secure mode reject message and release the NAS connection instead of sending a NAS secure mode complete message.

[0096] In some examples, if the AMF successfully verifies the NAS safe mode completion message, the AMF successfully confirms that the Subscription Permanent Identifier (SUPI) received from the UE's home network matches the SUPI used by the UE. However, the integrity check of the NAS safe mode completion message at the AMF may fail for reasons other than a SUPI mismatch.

[0097] Figure 3 These are merely examples of signals and operations, and variations are considered to be within the scope of this disclosure. In embodiments, signals and operations may include... Figure 3 Other signals and operations not shown. In embodiments, signals and operations may not include... Figure 3 Each signal and operation is shown. In an embodiment, the signals and operations can be used with... Figure 3 Different connections are shown to achieve this. Such and other embodiments are considered to be within the scope of this disclosure.

[0098] Figure 4This is a diagram illustrating an example embodiment of the operation of the uplink and downlink NAS count increment process according to one aspect of this disclosure. It should be understood that the described signals may have associated operations, and the described operations may have associated signals. Therefore, the described signals may also relate to operations, and the described operations may also relate to signals. Furthermore, Figure 4 This will describe the signals between various network components and the operations performed by these components, such as... Figure 4 Those shown at the top. Specifically, these components include the UE (e.g., Figure 1 UE 150) and wireless communication systems (e.g., Figure 1 and Figure 2 The core network's AMF (e.g., network system) of the network system) Figure 2 (AMF 212). The network components are illustrative, and it is conceivable that other components may be involved in the signals, or that other components may perform operations. In some examples, each network component may use a signal with, for example, AMF 212. Figure 14 The apparatus of the components shown is used to implement the operation. One or more of the following operations can be implemented in conjunction with the operations of this disclosure, such as those referenced above. Figures 1-3 Examples of discussion.

[0099] At a higher level, the AMF and UE can independently maintain and track downlink NAS counts (associated with downlink NAS messages from the AMF to the UE) and uplink NAS counts (associated with uplink NAS messages from the UE to the AMF). At the start of the NAS SMC procedure, the downlink NAS count and uplink NAS count can be reset to the same value. The AMF can increment its local downlink NAS count for each transmitted NAS SMC message, and the UE can increment its local downlink NAS count for each received NAS SMC message that successfully passes the NAS security check. Similarly, the UE can increment its local uplink NAS count for each transmitted NAS security mode message, and the AMF can increment its local uplink NAS count for each received NAS security mode message that successfully passes the NAS security check.

[0100] For example, in operation 401, the AMF sets the downlink NAS count and uplink NAS count at the AMF to 0. The NAS count value can correspond to a combination of an overflow value and a NAS message sequence number (e.g., denoted as SQN), calculated, for example, by applying a logical OR operation to the overflow value and SQN. In the example, the NAS count can be a 24-bit value, the SQN can correspond to the lower 8 bits of the NAS count, and the overflow value can correspond to the higher 16 bits of the NAS count.

[0101] In Operation 402a, the AMF sends a NAS SMC message and the UE receives the NAS SMC message. The NAS SMC message may include a MAC-I and an SQN with a value set to 0 (e.g., based on the current AMF downlink NAS count). The NAS SMC message may also include information as referenced above. Figure 3 See Operation 301b for further information. MAC-I can be used for integrity protection. In the example, MAC-I can be calculated based on an integrity algorithm and an integrity key, and can be used by the receiver to check the integrity of the corresponding message. That is, NAS SMC messages can be protected for integrity.

[0102] In operation 402b, after sending the NAS SMC message, the AMF increments the AMF downlink NAS count by 1, and therefore the AMF downlink NAS count can have a value of 1 after the increment.

[0103] In Operation 403a, the UE can verify the integrity of the received NAS SMC message. If the verification is successful, the UE increments the downlink NAS count at the UE by 1. The UE uses the SQN value included in the NAS SMC message and the calculated NAS-MAC (or MAC-I) value in the NAS SMC message for verification.

[0104] In operation 403b, after successfully receiving and verifying the NAS SMC message from the AMF and incrementing the UE downlink NAS count, the UE downlink NAS count has a value of 1. For example, the UE can set the UE downlink NAS count to 0 at the start of the NAS SMC procedure.

[0105] In operation 403c, before sending a response to the NAS SMC message received at operation 302a, the UE may have an uplink NAS count with a value of 0. For example, the UE may set its uplink NAS count to 0 at the start of the NAS SMC procedure.

[0106] In Operation 404a, based on successful verification of the NAS SMC message, the UE sends a NAS secure mode completion message and the AMF receives it. The NAS secure mode completion message can be encrypted (e.g., using a security context established based on information from the NAS SMC message, as referenced above). Figure 3 As described in Operation 302b), the NAS security mode completion message may include MAC-I. The NAS security mode completion message may also include an SQN with a value set to 0 (e.g., based on the current UE uplink NAS count). However, if authentication fails, the UE may send a NAS security mode rejection message to indicate rejection of the NAS SMC.

[0107] In operation 404b, after sending the NAS secure mode complete message, the UE increments the UE uplink NAS count by 1, and therefore the UE uplink NAS count can have a value of 1 after the increment.

[0108] In Operation 405, the AMF can verify the received NAS secure mode complete message. Verification may include decryption and checking integrity protection. After successfully receiving and verifying the NAS secure mode complete message from the UE, the AMF increments the AMF uplink NAS count by 1, and therefore the AMF uplink NAS count can have a value of 1 after the increment.

[0109] If the AMF fails to verify the NAS safe mode complete message, or receives a NAS safe mode reject message instead of a NAS safe mode complete message, the AMF can abort the NAS SMC process and perform error handling (e.g., retry the NASSMC process).

[0110] Figure 4 These are merely examples of signals and operations, and variations are considered to be within the scope of this disclosure. In embodiments, signals and operations may include... Figure 4 Other signals and operations not shown. In embodiments, signals and operations may not include... Figure 4 Each signal and operation is shown. In an embodiment, the signals and operations can utilize [the following]. Figure 4 Different connections are shown to achieve this. Such and other embodiments are considered to be within the scope of this disclosure.

[0111] The following will be a reference Figure 5 More comprehensively, the AMF can use the uplink NAS count in the NAS security mode completion message (received from the UE) as input to the KDF to generate a security key (e.g., K...). gNB The generated key is then sent to the corresponding access network node (e.g., a base station). The security key can be used to protect subsequent communication between the UE and the base station (e.g., for performing the AS SMC procedure). The UE can use the UE uplink NAS count included in the NAS security mode completion message (sent to the AMF) as input to the same KDF to generate a security key for performing the AS SMC procedure with the access network node (e.g., K...). gNBFor example, during the AS SMC process, the access network node can send an AS SMC message to the UE, which can be secured using a security key generated by the AMF (e.g., for encryption and integrity protection). If the UE successfully authenticates (e.g., decrypts and checks the integrity protection) the AS SMC message, the UE can respond using AS security mode. However, if authentication fails, the UE can reject the message using AS security mode. Those skilled in the art will understand the AS SMC process.

[0112] Under normal operating conditions, the NAS SMC message sent by the AMF in operation 301b can successfully reach the UE, and the corresponding NAS safe mode completion message sent by the UE in operation 302b can successfully reach the AMF. However, in some cases, the NAS SMC message may fail to reach the UE. As mentioned above, the AMF can retransmit the NAS SMC message. To do this, the AMF can start a retransmission timer (e.g., timer T3560) after sending the NAS SMC message to the UE. The AMF can retransmit the NAS SMC message when timer T3560 expires for the first time, and can reset and restart timer T3560. This retransmission can be repeated four times. That is, the NAS SMC process will be aborted when timer T3560 expires for the fifth time. Upon receiving the NAS safe mode completion message, the AMF can stop timer T3560.

[0113] Figure 5 This is a diagram illustrating an example security key misalignment scenario according to one aspect of this disclosure. It should be understood that the described signal may have associated operations, and the described operation may have associated signals. Therefore, the described signal may also relate to an operation, and the described operation may also relate to a signal. Furthermore, Figure 5 This will describe the signals between various network components and the operations performed by these components, such as... Figure 5 Those shown at the top. Specifically, these components include the UE (e.g., Figure 1 UE 150), gNB (e.g., Figure 1 Network node 120 or Figure 2 Nodes in RAN 225) and wireless communication systems (e.g., Figure 1 and Figure 2 The core network's AMF (e.g., network system) of the network system) Figure 2 (AMF 212). The network components are illustrative, and it is conceivable that other components may be involved in the signals, or that other components may perform operations. In some examples, each network component may use a signal with, for example, AMF 212. Figure 14The apparatus of the components shown is used to implement the operation. One or more of the following operations can be implemented in conjunction with the operations of this disclosure, such as those referenced above. Figures 1-4 Examples of discussion.

[0114] exist Figure 5 In this context, uplink communication from the UE to the AMF can be transmitted via the gNB, and downlink communication from the AMF to the UE can also be transmitted via the gNB. Furthermore, as referenced above... Figure 4 As stated above, each of the AMF and UE can perform uplink and downlink NAS count incrementing. For simplicity, Figure 5 The data does not show the increasing NAS counts for both uplink and downlink.

[0115] In Operation 501, the UE sends a registration request message and the AMF receives the registration request message. The registration request message may include various information, such as, but not limited to, registration type, UE network capabilities, and UE security capabilities.

[0116] In Operation 502, the AMF initiates the master authentication process with the UE. Those skilled in the art will understand the master authentication process.

[0117] In Operation 503a, the AMF sends a NAS SMC message and the UE receives the NAS SMC message, designated as NAS SMC#1. NAS SMC#1 can be integrity protected and can include elements referenced above. Figure 3 The information discussed in Operation 301b is essentially similar.

[0118] In operation 503b, after sending the NAS SMC#1 message, the AMF starts a retransmission timer, designated T3560#1. The AMF can configure the retransmission timer to have a specific duration, for example, as specified in the TS 24.501 document.

[0119] In operation 503c, when the UE receives NAS SMC#1, the UE verifies (e.g., checks integrity) NAS SMC#1. In the example scenario shown, the verification is successful, and therefore the UE proceeds to operations 503d and 503e. In operation 503d, the UE responds to the AMF by sending a NAS Secure Mode Completion Message (denoted as NAS SMP#1). NAS SMP#1 can perform encryption and integrity protection based on the information in NAS SMC#1. In operation 503e, based on the successful verification, the UE generates a security key, denoted as K, using the uplink NAS count from NAS SMP#1. gNB #1.

[0120] During operation 504a, retransmission timer T3560#1 expired.

[0121] In operation 504b, based on the expiration of the retransmission timer and the AMF's failure to receive NAS SMP#1 (e.g., due to unstable conditions on the air interface, or an unstable link between the UE and the AMF at the time), the AMF sends a new NAS SMC message to the UE, denoted as NAS SMC#2. NAS SMC#2 is a retransmission of NAS SMC#1. In operation 504c, the AMF starts a new retransmission timer, denoted as T3560#2. The retransmission timer can be implemented in any suitable manner. For example, T3560#2 and T3560#1 can be based on the same hardware and / or software counters or different hardware and / or software counters.

[0122] In operation 504d, when the UE receives NAS SMC#2, the UE verifies (e.g., checks integrity) NAS SMC#2. In the example scenario shown, the verification is successful, and therefore the UE proceeds to operations 504e and 504f. In operation 504e, the UE responds to the AMF by sending a NAS Secure Mode Completion Message (denoted as NAS SMP#2). NAS SMP#2 can perform encryption and integrity protection based on the information in NAS SMC#2. In operation 504f, the UE uses the uplink NAS count from NAS SMP#2 to generate a security key, denoted as K. gNB #2.

[0123] In Operation 505a, since the AMF receives NAS SMP #1 before NAS SMP #2, the AMF continues to verify (e.g., decrypt and check integrity) NAS SMP #1. In the example scenario shown, the verification is successful, and therefore the AMF continues to use the uplink NAS count from NAS SMP #1 to generate a security key, denoted as K. gNB #1. Furthermore, based on the successful reception of NASSMP#1 (indicating successful completion of the NAS SMC), the AMF can stop retransmission timer T3560#2. In operation 505b, the AMF sends an initial context establishment message to the gNB communicating with the UE, where the initial context establishment information includes K... gNB #1.

[0124] In Operation 506a, the gNB sends an AS SMC message and the UE receives the AS SMC message (e.g., encrypted and integrity protected), where the key uses K. gNB #1 is generated as input, and the UE uses a key to verify (e.g., decrypt and check integrity protection) AS SMC, which uses K gNB#2 is generated as input. That is, the gNB and UE use different security keys for AS communication. Therefore, authentication at the UE may fail. In Operation 506b, due to authentication failure, the UE sends an AS SMC failure message and the gNB receives the AS SMC failure message.

[0125] In Operation 507, based on the received AS SMC failure message, the gNB sends an RRC release message and the UE receives the RRC release message. In the example, the RRC release message may include a wait time, denoted as waitTime, which specifies the amount of time the UE can wait before initiating another RRC connection request.

[0126] Figure 5 These are merely examples of signals and operations, and variations are considered to be within the scope of this disclosure. In embodiments, signals and operations may include... Figure 5 Other signals and operations not shown. In embodiments, signals and operations may not include... Figure 5 Each signal and operation is shown. In an embodiment, the signals and operations can utilize [the following]. Figure 5 Different connections are shown to achieve this. Such and other embodiments are considered to be within the scope of this disclosure.

[0127] As from Figure 5 In the example scenario shown, it can be observed that there is a security key misalignment between the UE and the gNB, where the UE utilizes K gNB #2 (generated based on the uplink NAS count associated with the response NAS SMP#2 to NAS SMC#2), while AMF provides K to gNB. gNB #1 (generated based on the uplink NAS count associated with the response NAS SMP#1 to NAS SMC#1). It can be further observed that, due to the expiration of timer T3560#1, after the AMF retransmits the NAS SMC message (NAS SMC#2), NAS SMP#1 (the response to NAS SMC#1) arrives at the AMF, while the UE successfully processes NAS SMC#2, resulting in a misalignment of the security key.

[0128] Therefore, this disclosure provides techniques for performing NAS SMC procedures that support the generation of secure keys (e.g., K... gNB To avoid mismatches between the NAS SMC and related NAS counts at the UE and network.

[0129] The following describes an example operation to avoid security key misalignment between the UE and the gNB. Figure 6 and Figures 8-11Example signals and operations for performing the NAS SMC procedure are shown, which supports avoiding mismatches between the NAS SMC and associated NAS counts at the UE and network. Figure 7 Example NAS security mode message transaction ID is shown. Figure 12 Example operation of a network device (e.g., a core network entity) is shown. Figure 13 An example operation of the UE is shown. Figure 6 and Figures 8-11 In this context, uplink communication from the UE to the AMF can be sent via the gNB, and downlink communication from the AMF to the UE can also be sent via the gNB, as referenced above. Figure 5 As stated above. For simplicity, gNB in Figure 6 and Figures 8-11 Not shown in the image. Additionally, see the references above. Figure 4 Each of the AMF and UE can perform uplink and downlink NAS count incrementing. For simplicity, uplink and downlink NAS count incrementing is... Figure 6 , Figure 8 and Figures 10-11 Not shown in the image.

[0130] Figure 6 This diagram illustrates an example embodiment of a NAS SMC procedure according to an aspect of this disclosure, which supports avoiding mismatches in NAS SMC and associated NAS counts between the UE and the network. It should be understood that the described signals may have associated operations, and the described operations may have associated signals. Therefore, the described signals may also relate to operations, and the described operations may also relate to signals. Furthermore, Figure 6 This will describe the signals between various network components and the operations performed by these components, such as... Figure 6 Those shown at the top. Specifically, these components include the UE (e.g., Figure 1 UE 150) and wireless communication systems (e.g., Figure 1 and Figure 2 The core network's AMF (e.g., network system) of the network system) Figure 2 (AMF 212). The network components are illustrative, and it is conceivable that other components may be involved in the signals, or that other components may perform operations. In some examples, each network component may use a signal with, for example, AMF 212. Figure 14 The apparatus of the components shown is used to implement the operation. One or more of the following operations can be implemented in conjunction with the operations of this disclosure, such as those referenced above. Figures 1-5 Examples of discussion.

[0131] In Operation 601, the UE sends a registration message and the AMF receives the registration message. The registration message can be a registration request, similar to the one mentioned above. Figure 5 Operation 501 discusses the registration request and may optionally include an indication of whether the UE supports NAS security mode message transaction identifier processing.

[0132] In operation 602, upon receiving a registration message, the AMF stores the UE's capabilities. If the UE indicates support for the NAS security mode message transaction ID, the AMF can continue to include the NAS security mode message transaction ID in the NAS SMC message given to the UE, and can generate a security key (e.g., K). gNB Before proceeding, check the NAS security mode message transaction ID in the NAS security mode completion message from the UE, as shown below. However, if the NAS security mode message transaction ID indicated by the UE is not supported, the AMF can perform the operation as described in the reference above. Figures 2-4 The NAS SMC process described above.

[0133] In operation 603, based on the UE's support for NAS security mode message transaction ID processing, the AMF settings must be included in the NASSMC message to be transmitted to the UE's downlink bitmap (e.g., the first bitmap). See below for reference. Figure 7 As discussed, the AMF can set a downlink bitmap to indicate the number of retransmissions associated with a NAS SMC message. The first bit of the bitmap can be used as the NAS security mode message transaction ID for the NAS SMC message.

[0134] Figure 7 This is a diagram illustrating an example embodiment of a NAS security mode message transaction identifier according to an illustrative aspect of this disclosure. (See diagram below.) Figure 7 As shown, the NAS security mode message transaction ID can include multiple bits. Figure 7 In the example shown, the NAS Security Mode Message Transaction ID consists of 8 bits, where the lower 3 bits (least significant bits) indicate the number of retransmissions for the NAS SMC message, and the higher 5 bits (most significant bits) are reserved (or stored). For the initial transmission of the NAS SMC message, the AMF can set the lower 3 bits of the NAS Security Mode Message Transaction ID to 0. For the first retransmission of the NAS SMC message, the AMF can set the lower 3 bits to indicate a value of 1. For the second retransmission of the NAS SMC message, the AMF can set the lower 3 bits to indicate a value of 2. For the third retransmission of the NAS SMC message, the AMF can set the lower 3 bits to indicate a value of 3. For the fourth retransmission of the NAS SMC message, the AMF can set the lower 3 bits to indicate a value of 4.

[0135] Figure 7The NAS security mode message transaction ID is illustrative only, and variations are considered to be within the scope of this disclosure. Typically, the NAS security mode message transaction ID can use any suitable number of bits (e.g., 2, 3, 4, 5 or more) and any suitable bit positions to indicate the number of retransmissions associated with a NAS SMC message transmission.

[0136] Back Figure 6 In Operation 604, the AMF sends a NAS SMC message and the UE receives the NAS SMC message. The NAS SMC message may include a downlink bitmap. The NAS SMC message may also include information as described in the reference above. Figure 3 Operation 301b and / or Figure 4 Other information discussed in Operation 402a (e.g., ngKSI, the selected NAS integrity algorithm, MAC-I, etc.). NAS SMC messages can be referenced as above. Figure 3 As discussed in Operation 301b, it is protected for integrity. After sending the NAS SMC message, the AMF can start the retransmission timer as described above.

[0137] In operation 605a, upon receiving a NAS SMC message, the UE verifies the received NAS SMC message and the downlink bitmap. For example, verification may include verifying the integrity protection of the NAS SMC message (e.g., using information indicated by the NAS SMC message) and checking whether the UE security capabilities sent by the AMF match the UE security capabilities stored at the UE. In the example shown, verification is successful. Based on the successful verification, the UE increments the UE downlink NAS count by 1 and continues with operations 605b and 606.

[0138] In Operation 605b, the UE sets the uplink bitmap based on the downlink bitmap in the received NAS SMC message. For example, the UE can set the uplink bitmap to the downlink bitmap in the received NAS SMC message. The UE can include the uplink bitmap in the NAS Secure Mode Complete message to be sent to the AMF in response to the received NAS SMC message.

[0139] In operation 606, the UE sends a NAS secure mode completion message including an uplink bitmap, and the AMF receives the message. The UE can perform integrity protection and encryption on the NAS secure mode completion message based on the information provided in the NAS SMC message.

[0140] In Operation 607, upon receiving a NAS Secure Mode Complete message, the AMF verifies the received NAS Secure Mode Complete message. Verification may include decrypting the NAS Secure Mode Complete message and checking the integrity protection of the NAS Secure Mode Complete message (e.g., based on information such as the NAS Integrity Algorithm and the ngKSI included in the NAS SMC message, as referenced above). Figure 3 (As described in operation 301b). In the example shown, verification is successful. Based on the successful verification, the AMF increments the AMF downlink NAS count by 1. The AMF also verifies whether the received uplink bitmap corresponds to the downlink bitmap included in the NAS SMC message sent at operation 604. That is, the AMF can compare the uplink bitmap (in the received NAS security mode completion message) and the downlink bitmap (included in the last sent NAS SMC message). If the comparison results in a match, the AMF generates a security key (e.g., K) based on the uplink NAS count associated with the received NAS security mode completion message. gNB For example, the AMF can determine the uplink NAS count based on the SQN in the received NAS security mode completion message and the estimated uplink overflow value.

[0141] However, if a mismatch is found between the uplink bitmap and the downlink bitmap, the AMF can continue monitoring for NAS Secure Mode Complete messages from the UE, which are responses to the NAS SMC message sent at Operation 604. In other words, the AMF can wait for a corresponding bitmap response from the UE. Furthermore, the AMF can maintain (e.g., to avoid stopping) a retransmission timer and retransmit the NAS SMC message when the retransmission timer expires. That is, if the AMF receives a NAS Secure Mode Complete message with an uplink bitmap that differs from the downlink bitmap in the most recently sent NAS SMC message, the AMF can maintain the retransmission timer to continue monitoring for NAS Secure Mode Complete messages without generating a security key.

[0142] The following will be a reference Figures 10-11 More comprehensively, the security key is generated based on the matching between the downlink bitmap (in the sent NASSMC message) and the uplink bitmap (in the received NAS security mode completion message), and the retransmission timer is allowed to continue in the event of a mismatch (based on the comparison), which avoids the key misalignment problem discussed in this paper.

[0143] In some cases, the UE may fail to verify the NAS SMC message in Operation 605a, and therefore the UE may send a NAS Secure Mode Reject message. In some cases, the AMF may fail to verify the NAS Secure Mode Complete message in Operation 607. If the AMF fails to verify the NAS Secure Mode Complete message, or receives a NAS Secure Mode Reject message instead of a NAS Secure Mode Complete message, the AMF may abort the NAS SMC procedure and perform error handling (e.g., retry the NAS SMC procedure).

[0144] Figure 6 These are merely examples of signals and operations, and variations are considered to be within the scope of this disclosure. In embodiments, signals and operations may include... Figure 6 Other signals and operations not shown. In embodiments, signals and operations may not include... Figure 6 Each signal and operation is shown. In an embodiment, the signals and operations can be used with... Figure 6 Different connections are shown to achieve this. Such and other embodiments are considered to be within the scope of this disclosure.

[0145] Figure 8 This diagram illustrates an example embodiment of a NAS SMC procedure according to an aspect of this disclosure, which supports avoiding mismatches in NAS SMC and associated NAS counts between the UE and the network. It should be understood that the described signals may have associated operations, and the described operations may have associated signals. Therefore, the described signals may also relate to operations, and the described operations may also relate to signals. Furthermore, Figure 8 This will describe the signals between various network components and the operations performed by these components, such as... Figure 8 Those shown at the top. Specifically, these components include the UE (e.g., Figure 1 UE 150) and wireless communication systems (e.g., Figure 1 and Figure 2 The core network's AMF (e.g., network system) of the network system) Figure 2 (AMF 212). The network components are illustrative, and it is conceivable that other components may be involved in the signals, or that other components may perform operations. In some examples, each network component may use a signal with, for example, AMF 212. Figure 14 The apparatus of the components shown is used to implement the operation. One or more of the following operations can be implemented in conjunction with the operations of this disclosure, such as those referenced above. Figures 1-6 Examples of discussion.

[0146] Generally speaking, Figure 8 Signals and operations include many aspects, including with Figure 6The operations have similar characteristics. For example, operations 801 and 802 are similar to operations 601 and 602, respectively. Therefore, for the sake of brevity, the details of these operations will not be repeated here; please refer to the corresponding descriptions above.

[0147] In operation 803, based on the UE's support for NAS security mode message transaction ID processing (e.g., indicated in the registration message of operation 801), the AMF generates a new NAS ID (e.g., a first NAS ID) to be included in the NAS SMC message transmitted to the UE. The NAS ID can be used as the NAS security mode message transaction ID for the NAS SMC message.

[0148] During operation 804, the AMF sends a NAS SMC message and the UE receives the NAS SMC message. The NAS SMC message may include the NAS ID. The NAS SMC message may also include information as described above. Figure 3 Operation 301b and / or Figure 4 Other information discussed in Operation 402a (e.g., ngKSI, the selected NAS integrity algorithm, MAC-I, etc.). NAS SMC messages can be referenced as above. Figure 3 As discussed in Operation 301b, it is protected for integrity. After sending the NAS SMC message, the AMF can start the retransmission timer as described above.

[0149] In operation 805, upon receiving a NAS SMC message, the UE verifies the received NAS SMC message. For example, verification may include verifying the integrity protection of the NAS SMC message (e.g., using information indicated by the NAS SMC message) and checking whether the UE security capabilities sent by the AMF match the UE security capabilities stored in the UE. If the verification is successful, the UE increments the UE downlink NAS count by 1 and determines that it should respond to the received NAS SMC message using the same NAS ID as received in the NAS SMC message.

[0150] In operation 806, the UE sends a NAS security mode completion message including the NAS ID, and the AMF receives this message. The UE can protect and encrypt the integrity of the NAS security mode based on the information provided in the NAS SMC message.

[0151] In Operation 807, upon receiving a NAS Secure Mode Complete message, the AMF verifies the received NAS Secure Mode Complete message. Verification may include decrypting the NAS Secure Mode Complete message and checking the integrity protection of the NAS Secure Mode Complete message (e.g., based on information such as the NAS Integrity Algorithm and the ngKSI included in the NAS SMC message, as referenced above). Figure 3 (As described in Operation 301b). If the verification is successful, the AMF increments the AMF uplink NAS count by 1. The AMF also verifies that the NAS ID in the received NAS Security Mode Complete message is the same as the NAS ID included in the NAS SMC message sent at Operation 804. That is, the AMF can compare the NAS ID in the received NAS Security Mode Complete message with the NAS ID included in the last sent NAS SMC message. If the comparison results in a match, the AMF generates a security key (e.g., K) based on the uplink NAS count associated with the received NAS Security Mode Complete message. gNB For example, the AMF can determine the uplink NAS count based on the SQN in the received NAS security mode completion message and the estimated uplink overflow value. However, if a mismatch exists, the AMF can maintain (e.g., to avoid stopping) a retransmission timer and continue monitoring for NAS security mode completion messages without generating a security key, as referenced above. Figure 6 As described in Operation 607. When the retransmission timer expires, the AMF can retransmit the NAS SMC message.

[0152] The following will be a reference Figures 10-11 More comprehensively, a security key is generated based on NAS ID matching (by comparing the sent NAS SMC message with the received NAS Security Mode Complete message), and the retransmission timer is allowed to continue in the event of a NAS ID mismatch (based on the comparison), which avoids the key mismatch problem discussed in this paper.

[0153] In some cases, the UE may fail to verify the NAS SMC message during Operation 805a, and therefore the UE may send a NAS Secure Mode Reject message. In some cases, the AMF may fail to verify the NAS Secure Mode Complete message during Operation 807. If the AMF fails to verify the NAS Secure Mode Complete message, or receives a NAS Secure Mode Reject message instead of a NAS Secure Mode Complete message, the AMF may abort the NAS SMC procedure and perform error handling (e.g., retry the NAS SMC procedure).

[0154] Figure 8 These are merely examples of signals and operations, and variations are considered to be within the scope of this disclosure. In embodiments, signals and operations may include... Figure 8 Other signals and operations not shown. In embodiments, signals and operations may not include... Figure 8 Each signal and operation is shown. In an embodiment, the signals and operations can be used with... Figure 8 Different connections are shown to achieve this. Such and other embodiments are considered to be within the scope of this disclosure.

[0155] Figure 9 This diagram illustrates an example embodiment of a NAS SMC procedure according to an aspect of this disclosure, which supports avoiding mismatches in NAS SMC and associated NAS counts between the UE and the network. It should be understood that the described signals may have associated operations, and the described operations may have associated signals. Therefore, the described signals may also relate to operations, and the described operations may also relate to signals. Furthermore, Figure 9 This will describe the signals between various network components and the operations performed by these components, such as... Figure 9 Those shown at the top. Specifically, these components include the UE (e.g., Figure 1 UE 150) and wireless communication systems (e.g., Figure 1 and Figure 2 The core network's AMF (e.g., network system) of the network system) Figure 2 (AMF 212). The network components are illustrative, and it is conceivable that other components may be involved in the signals, or that other components may perform operations. In some examples, each network component may use a signal with, for example, AMF 212. Figure 14 The apparatus of the components shown is used to implement the operation. One or more of the following operations can be implemented in conjunction with the operations of this disclosure, such as those referenced above. Figures 1-5 Examples of discussion.

[0156] Generally speaking, Figure 9 Signals and operations include many aspects, including with Figure 4 The operations share similar characteristics. For example, operations 901, 902a, 902b, 903a, 903b, 903c, 904a, 904b, and 905 are similar to operations 401, 402a, 402b, 403a, 403b, 403c, 404a, 404b, and 405, respectively. Therefore, for the sake of brevity, the details of these operations will not be repeated here, and you can refer to the corresponding descriptions above.

[0157] In operation 906, upon successfully receiving the NAS security mode completion message from the UE, the AMF generates a security key (e.g., K) based on the match between the downlink SQN in the NAS SMC message sent at operation 902a and the uplink SQN in the NAS security mode completion message received at operation 904a. gNB To this end, AMF can verify the NAS secure mode completion message. Verification may include decrypting the NAS secure mode completion message and checking the integrity protection of the NAS secure mode completion message (e.g., based on information such as the NAS integrity algorithm and the ngKSI included in the NAS SMC message, as referenced above). Figure 3(As described in Operation 301b). If verification is successful, the AMF can compare the downlink SQN with the uplink SQN. Based on the match of the comparison result, the AMF generates a security key. If the comparison indicates a mismatch (e.g., the downlink SQN is greater than the uplink SQN), the AMF can maintain (e.g., avoid stopping) the retransmission timer and continue monitoring for NAS security mode completion messages without generating a security key, as described above. Figure 6 As described in Operation 607. When the retransmission timer expires, the AMF can retransmit the NASSMC message.

[0158] The following will be a reference Figures 10-11 More comprehensively, a security key is generated when there is a match between the downlink SQN (in the sent NAS SMC message) and the uplink SQN (in the received NAS Security Mode Complete message), and the retransmission timer is allowed to continue (by comparison) when there is a mismatch. This avoids the key misalignment problem discussed in this paper.

[0159] Figure 9 These are merely examples of signals and operations, and variations are considered to be within the scope of this disclosure. In embodiments, signals and operations may include... Figure 9 Other signals and operations not shown. In embodiments, signals and operations may not include... Figure 9 Each signal and operation is shown. In an embodiment, the signals and operations can be used with... Figure 9 Different connections are shown to achieve this. Such and other embodiments are considered to be within the scope of this disclosure.

[0160] Figure 10 This is a schematic diagram of an example embodiment of the NAS SMC process, which supports avoiding mismatches in NAS SMC and related NAS counts between the UE and the network. It should be understood that the described signals may have associated operations, and the described operations may have associated signals. Therefore, the described signals may also relate to operations, and the described operations may also relate to signals. Furthermore, Figure 10 This will describe the signals between various network components and the operations performed by these components, such as... Figure 10 Those shown at the top. Specifically, these components include the UE (e.g., Figure 1 UE 150) and wireless communication systems (e.g., Figure 1 and Figure 2 The core network's AMF (e.g., network system) of the network system) Figure 2 (AMF 212). The network components are illustrative, and it is conceivable that other components may be involved in the signals, or that other components may perform operations. In some examples, each network component may use a signal with, for example, AMF 212. Figure 10The apparatus of the components shown is used to implement the operation. One or more of the following operations can be implemented in conjunction with the operations of this disclosure, such as those referenced above. Figure 6 and Figures 8-9 Examples of discussion.

[0161] In operation 1010, the AMF sets (or generates) the first NAS security mode message transaction ID to a specific value. In one aspect, the NAS security mode message transaction ID can be a bitmap indicating the number of retransmissions of the NAS SMC message to be sent to the UE, as referenced above. Figures 6-7 As described above. On the other hand, the NAS security mode message transaction ID can be a NAS ID specific to the upcoming NAS SMC message transmission (e.g., in operation 1012), as referenced above. Figure 8 As described above. On the other hand, the NAS security mode message transaction ID can be as referenced above. Figure 4 and Figure 9 The NAS downlink message SQN mentioned above.

[0162] In operation 1012, the AMF sends a NAS SMC message including the first NAS security mode message transaction ID, and the UE receives the message. The NAS SMC message may also include information about the UE's security capabilities (e.g., playback of UE security capabilities) and information for establishing a security context between the UE and the core network (e.g., key set identifier (ngKSI), encryption algorithm, integrity algorithm, NAS message authentication code). The AMF can perform integrity protection on the NAS SMC message.

[0163] In operation 1014, after sending the NAS SMC message to the UE, the AMF starts a retransmission timer (e.g., timer T3560). The AMF can configure the retransmission timer to have a duration of 1030. In the example, the duration 1030 can be set according to the T3560 timer duration specified in the 3GPP standard. Typically, the duration 1030 can be any suitable time value (e.g., taking into account the round-trip delay between the AMF and the UE).

[0164] In operation 1016, upon receiving a NAS SMC message, the UE can set a second NAS security mode message transaction ID to be included in the response to the received NAS SMC message (e.g., a NAS security mode completion message). When the first NAS security mode message transaction ID is a downlink bitmap or NAS ID, the UE can set the second NAS security mode message transaction ID to the first NAS security mode message transaction ID in the NAS SMC message received at operation 1012. When the first NAS security mode message transaction ID is a NAS downlink message SQN, the second NAS security mode message transaction ID is a NAS uplink message SQN, where the UE can generate the NAS uplink message SQN based on the UE uplink NAS count. Before setting the second NAS security mode message transaction ID, the UE can verify (e.g., check integrity protection) the received NAS SMC message and set the second NAS security mode message transaction ID based on successful verification.

[0165] In operation 1018, the UE sends a NAS security mode completion message including the second NAS security mode message transaction ID, and the AMF receives this message. As shown in the figure, the NAS security mode completion message arrives at the AMF before the retransmission timer expires. The NAS security mode completion message can be encrypted and protected for integrity as described above.

[0166] In operation 1020, upon receiving a NAS security mode completion message, the AMF compares the first NAS security mode message transaction ID (in the last sent NAS SMC message) with the second NAS security mode message transaction ID (in the received NAS security mode completion message). Before the comparison, the AMF may verify (e.g., decrypt and check integrity protection) the received NAS security mode completion message and perform the comparison based on successful verification as described above.

[0167] In operation 1022, the AMF determines whether the comparison meets a condition. For example, the condition could correspond to a match between the first NAS security mode message transaction ID (in the last sent NAS SMC message) and the second NAS security mode message transaction ID (in the received NAS security mode completion message). If the comparison meets the condition, the AMF proceeds to operation 1026. In operation 1026, the AMF, for example, uses the uplink NAS count associated with the NAS security mode completion message as input to the KDF to generate a security key (e.g., K...). gNB ).

[0168] However, if the comparison at operation 1022 fails to meet the conditions, the AMF proceeds to operation 1024. In operation 1024, the AMF maintains (e.g., to avoid stopping) the retransmission timer, continues to monitor for NAS secure mode completion messages, and avoids generating a security key.

[0169] Figure 10 These are merely examples of signals and operations, and variations are considered to be within the scope of this disclosure. In embodiments, signals and operations may include... Figure 10 Other signals and operations not shown. In embodiments, signals and operations may not include... Figure 10 Each signal and operation is shown. In an embodiment, the signals and operations can be used with... Figure 10 Different connections are shown to achieve this. Such and other embodiments are considered to be within the scope of this disclosure.

[0170] Figure 11 This is a schematic diagram of an example embodiment of the NAS SMC process, which supports avoiding mismatches in NAS SMC and related NAS counts between the UE and the network. It should be understood that the described signals may have associated operations, and the described operations may have associated signals. Therefore, the described signals may also relate to operations, and the described operations may also relate to signals. Furthermore, Figure 11 This will describe the signals between various network components and the operations performed by these components, such as... Figure 10 Those shown at the top. Specifically, these components include the UE (e.g., Figure 1 UE 150) and wireless communication systems (e.g., Figure 1 and Figure 2 The core network's AMF (e.g., network system) of the network system) Figure 2 (AMF 212). The network components are illustrative, and it is conceivable that other components may be involved in the signals, or that other components may perform operations. In some examples, each network component may use a signal with, for example, AMF 212. Figure 11 The apparatus of the components shown is used to implement the operation. One or more of the following operations can be implemented in conjunction with the operations of this disclosure, such as those referenced above. Figure 6 and Figures 8-10 Examples of discussion.

[0171] In operation 1110, the AMF sets (or generates) the first NAS security mode message transaction ID to a specific value. For example, as referenced above. Figure 10As described in operation 1010, the first NAS security mode message transaction ID can be a downlink bitmap, a NAS ID, or a NAS message SQN. If the first NAS security mode message transaction ID is a downlink bitmap, the AMF can set the value of the downlink bitmap to 0 to indicate the initial transmission of the NAS SMC message.

[0172] In operation 1112, the AMF sends a first NAS SMC message including the first NAS security mode message transaction ID, and the UE receives the message. The first NAS SMC message may also include information as referenced above. Figure 11 Other information described in operation 1012. The first NAS SMC message can be protected for integrity.

[0173] In operation 1114, after sending the first NAS SMC message to the UE, the AMF starts the first retransmission timer (e.g., the first timer T3560). The AMF can configure the first retransmission timer to have a duration of 1140. In the example, the duration 1140 can be set according to the T3560 timer duration specified in the 3GPP standard. Typically, the duration 1140 can be any suitable time value (e.g., taking into account the round-trip delay between the AMF and the UE).

[0174] In operation 1116, based on the expiration of the first retransmission timer, the AMF sets the second NAS security mode message transaction ID. If the first NAS security mode message transaction ID is a NAS ID, the AMF can generate a new NAS ID and set the second NAS security mode message transaction ID to the newly generated NAS ID. If the first NAS security mode message transaction ID is a downlink bitmap, the AMF can set the downlink bitmap to a value of 1 to indicate that the upcoming second NAS SMC message transmission (e.g., at operation 1118) is the first retransmission of the first NAS SMC message. If the first NAS security mode message transaction ID is a NAS downlink message SQN, the AMF can set the second NAS security mode message transaction ID based on the current AMF downlink NAS count.

[0175] In operation 1118, the AMF sends a second NAS SMC message to the UE, including the second NAS security mode message transaction ID. The second NAS SMC message is a retransmission of the first NAS SMC message. The second NAS SMC message can be protected for integrity.

[0176] In operation 1120, after sending the second NAS SMC message to the UE, the AMF starts a second retransmission timer (e.g., second timer T3560). The AMF can configure the second retransmission timer to have the same duration 1140.

[0177] In operation 1122, when the UE receives the first NAS SMC message, the UE sets the third NAS security mode message transaction ID to be included in the response to be sent to the AMF (e.g., the first NAS security mode completion message). If the first NAS security mode message transaction ID is a downlink bitmap or NAS ID, the UE can set the third NAS security mode message transaction ID to the first NAS security mode message transaction ID in the first NAS SMC message received at operation 1112. If the first NAS security mode message transaction ID is a NAS downlink message SQN, then the third NAS security mode message transaction ID is a NAS uplink message SQN, and therefore, the UE can generate the NAS uplink message SQN based on the current UE uplink NAS count. Before setting the third NAS security mode message transaction ID, the UE can verify (e.g., check integrity protection) the received first NAS SMC message and set the third NAS security mode message transaction ID based on successful verification.

[0178] In operation 1124, the UE sends a first NAS security mode completion message including the third NAS security mode message transaction ID, and the AMF receives the message. As shown in the figure, after the AMF retransmits the first NAS SMC message (as a second NAS SMC message) based on the expiration of the first retransmission timer, the first NAS security mode completion message in response to the first NAS SMC message arrives at the AMF.

[0179] In operation 1125, after sending the first NAS security mode completion message, the UE uses the uplink NAS count in the first NAS security mode completion message to generate the first security key (e.g., K). gNB ).

[0180] In operation 1126, upon receiving the first NAS security mode completion message, the AMF maintains the first retransmission timer, continues monitoring for NAS security mode completion messages, and avoids generating a security key if a comparison of the second NAS security mode message transaction ID (in the received first NAS security mode completion message) and the first NAS security mode message transaction ID (in the most recently sent second NAS SMC message) fails to meet a condition (e.g., a match condition). The comparison indicates a mismatch because the first NAS security mode completion message responded to the first NAS SMC message, not the most recently sent second NAS SMC message (the retransmitted NAS SMC). Before the comparison, the AMF may verify (e.g., decrypt and check integrity protection) the received first NAS security mode completion message and perform the comparison based on successful verification, as described above.

[0181] In operation 1128, when the UE receives the second NAS SMC message from operation 1118, the UE sets the fourth NAS security mode message transaction ID to be included in the response to be sent to the AMF (e.g., the second NAS security mode completion message). If the second NAS security mode message transaction ID is a downlink bitmap or NAS ID, the UE can set the fourth NAS security mode message transaction ID to the second NAS security mode message transaction ID in the second NAS SMC message received at operation 1118. If the second NAS security mode message transaction ID is a NAS downlink message SQN, then the fourth NAS security mode message transaction ID is a NAS uplink message SQN, and therefore, the UE can generate the NAS uplink message SQN based on the current UE uplink NAS count. Before setting the fourth NAS security mode message transaction ID, the UE can verify (e.g., check integrity protection) the received second NAS SMC message and set the fourth NAS security mode message transaction ID based on successful verification.

[0182] In operation 1130, the UE sends a second NAS security mode completion message including the fourth NAS security mode message transaction ID, and the AMF receives the message.

[0183] In operation 1131, after sending the second NAS security mode completion message, the UE uses the uplink NAS count in the second NAS security mode completion message to generate the second security key (e.g., K). gNB ).

[0184] exist Figure 11 In the example shown, the second NAS security mode completion message arrives at the AMF before the second retransmission timer expires. In operation 1132, when the AMF receives the second NAS security mode completion message, the AMF generates a security key (e.g., K) based on a comparison condition (e.g., a match condition) between the transaction ID of the sent second NAS security mode message (in the most recently sent second NAS SMC message) and the transaction ID of the received fourth NAS security mode message. gNB The comparison indicates a match because the second NAS security mode completion message responds to the second NAS SMC message. Before the comparison, the AMF can verify (e.g., decrypt and check integrity protection) the received second NAS security mode completion message and perform the comparison based on successful verification, as described above.

[0185] Subsequently, the AMF can transmit the security key generated by the AMF to the corresponding gNB communicating with the UE, where the gNB can use the security key generated by the AMF, and the UE can use the latest security key (second security key) generated by the UE to perform AS communication.

[0186] like Figure 11 As shown, both the security key generated by the AMF and the latest security key (the second security key) generated by the UE are based on the second NAS security mode completion message. Therefore, although the response to the first NAS SMC message (the first NAS security mode completion message) arrives at the AMF after the AMF retransmits the first NAS SMC message (as the second NAS SMC message) and the UE successfully processes the second NAS SMC message, there is no security key misalignment between the UE and the network.

[0187] Figure 11 These are merely examples of signals and operations, and variations are considered to be within the scope of this disclosure. In embodiments, signals and operations may include... Figure 11 Other signals and operations not shown. In embodiments, signals and operations may not include... Figure 11 Each signal and operation is shown. In an embodiment, the signals and operations can utilize [the following]. Figure 11 Different connections are shown to achieve this. Such and other embodiments are considered to be within the scope of this disclosure.

[0188] Figure 12 This is a flowchart illustrating an example operation of a network device according to one aspect of this disclosure. In one aspect, the network device may be a device or a network node of a core network entity of a wireless communication system's core network. In another aspect, the core network entity may correspond to the reference above. Figures 2-6 and Figures 8-11 The AMF mentioned above, and the wireless communication system can be as described in the reference above. Figures 1-2 The network system described above. In some examples, the network device can use a network with, for example, Figure 14 The device shown implements the operation using the components. Figure 12 The operations can include those mentioned above. Figures 1-11 A similar mechanism is being discussed.

[0189] At box 1202, the core network entity of the core network of the wireless communication system sends a NAS SMC message to the UE. The message includes information about the UE's security capabilities (e.g., playback of the UE's security capabilities), information for establishing a security context between the UE and the core network (e.g., key set identifier (ngKSI), encryption algorithm, integrity algorithm, NAS message authentication code), and a first NAS security mode message transaction ID.

[0190] At box 1204, the core network entity receives a NAS security mode completion message from the UE, which includes the second NAS security mode message transaction ID.

[0191] At box 1206, based on the condition that the comparison between the first NAS security mode message transaction ID and the second NAS security mode message transaction ID meets, the core network entity generates a security key (e.g., K). gNB The security key can be used to protect AS communication between the UE and the access network apparatus (e.g., base station) of the wireless communication system. In some aspects, generating the security key can also be based on a match between the second NAS security mode message transaction ID in the NAS security mode completion message and the second NAS security mode message transaction ID in the NAS SMC message. For example, when the comparison result is a match, the core network entity can use the uplink NAS count associated with the received NAS security mode completion message as input to the KDF to generate the security key.

[0192] In some respects, the first NAS security mode message transaction ID in a NAS SMC message may include a first NAS ID specific to the transmission of the NAS SMC message. The second NAS security mode message transaction ID in a NAS security mode completion message may include a second NAS ID, wherein the NAS security mode completion message may be a response to a NAS SMC message associated with the second NAS ID, for example, as referenced above. Figure 8 and Figures 10-11 As stated above.

[0193] In some respects, the first NAS security mode message transaction ID in a NAS SMC message may include a first bitmap, which includes an indication of the number of retransmissions of the NAS SMC message. The second NAS security mode message transaction ID in a NAS security mode completion message may include a second bitmap, where the NAS security mode completion message may be a response to a NAS SMC message associated with the second bitmap, for example, as referenced above. Figures 6-7 and Figures 10-11 As stated above.

[0194] In some respects, the first NAS security mode message transaction ID in the NAS SMC message corresponds to the NAS downlink message sequence number, and the second NAS security mode message transaction ID in the NAS security mode completion message corresponds to the NAS uplink message sequence number, for example, as referenced above. Figures 9-11 As stated above.

[0195] In some respects, sending a NAS SMC message at box 1202 can also be based on the expiration of a retransmission timer (e.g., the T3560 timer). In some respects, the core network entity can also generate a first NAS security mode message transaction ID based on the expiration of a retransmission timer.

[0196] In some respects, the core network entity can also receive another NAS security mode completion message from the UE, including the transaction ID of the third NAS security mode message. The core network entity can continue monitoring the NAS security mode completion message without generating a security key (e.g., K) if the comparison between the first and third NAS security mode message transaction IDs fails to meet a condition. gNB In other words, the core network entity can avoid generating a security key when the comparison fails. In some respects, the core network entity can also maintain a retransmission timer (e.g., a T3560 timer) based on the failure of a comparison between the first NAS security mode message transaction ID and the third NAS security mode message transaction ID. That is, the core network entity can avoid stopping the retransmission timer when the comparison fails.

[0197] In some respects, the core network entity can also receive a registration request message from the UE, which includes an indication of whether the UE supports the NAS security mode message transaction identifier.

[0198] Figure 12 The operations described are illustrative only, and variations are considered to be within the scope of this disclosure. In embodiments, the operations may include... Figure 12 Other boxes not shown in the diagram. In embodiments, the operation may not include... Figure 12 Each box is shown. In an embodiment, the operation can be in conjunction with... Figure 12 Different sequences of implementation are shown. Such and other embodiments are considered to be within the scope of this disclosure.

[0199] Figure 13 This is a flowchart illustrating an example operation of a UE according to one aspect of this disclosure. In one aspect, the UE can be referenced above. Figures 1-6 and Figures 8-11 The UE discussed corresponds to this. In some examples, the UE can use features such as Figure 14 The apparatus shown in the diagram is used to perform these operations. Figure 13 The operations can include those mentioned above. Figures 1-11 A similar mechanism is being discussed.

[0200] At box 1302, the UE receives a NAS SMC message from the core network entity of the wireless communication system's core network. This message includes information about the UE's security capabilities, integrity key information, and a first NAS security mode message transaction ID. The core network entity can be as described in the reference above. Figures 2-6 and Figures 8-11 The AMF mentioned above, and the wireless communication system can be as described in the reference above. Figures 1-2 The aforementioned network system.

[0201] At box 1304, the UE generates a second NAS security mode message transaction ID based on the first NAS security mode message transaction ID.

[0202] At frame 1306, the UE sends a NAS security mode completion message, which includes the second NAS security mode message transaction ID, to the core network entity.

[0203] In some respects, the first NAS security mode message transaction ID in the NAS SMC message includes a NAS ID specific to the transmission of the NAS SMC message. In some respects, as part of generating the second NAS security mode message transaction ID at box 1304, the UE sets the second NAS security mode message transaction ID based on the NAS ID in the NAS SMC message.

[0204] In some respects, the first NAS security mode message transaction ID in the NAS SMC message includes an indication of the number of retransmissions associated with the NAS SMC message. In some respects, as part of generating the second NAS security mode message transaction ID at box 1304, the UE sets the second NAS security mode message transaction ID based on the number of retransmissions associated with the NAS SMC message.

[0205] In some respects, the UE also sends a registration request message to the core network entity, which includes an indication of whether the UE supports NAS security mode message transaction identifiers.

[0206] Figure 13 The operations described are illustrative only, and variations are considered to be within the scope of this disclosure. In embodiments, the operations may include... Figure 13 Other boxes not shown in the diagram. In embodiments, the operation may not include... Figure 13 Each box is shown. In an embodiment, the operation can be in conjunction with... Figure 13 Different sequences of implementation are shown. Such and other embodiments are considered to be within the scope of this disclosure.

[0207] Now for reference Figure 14This diagram illustrates a block diagram of example components of a UE or network device. The device includes an electronic storage device 1410, a processor 1420, a memory 1450, and a network interface 1440. The various components can be communicatively coupled to each other. The processor 1420 can be and may include any type of processor, such as a single-core central processing unit (CPU), a multi-core CPU, a microprocessor, a digital signal processor (DSP), a system-on-a-chip (SoC), or any other type of processor. The memory 1450 can be a volatile type of memory, such as RAM, or a non-volatile type of memory, such as NAND flash memory. The memory 1450 includes processor-readable instructions executable by the processor 1420 to cause the device to perform various operations, including those described herein, such as... Figure 6 and Figures 8-13 The operation.

[0208] Electronic storage device 1410 can be and includes any type of electronic storage device for storing data, such as hard disk drives, solid-state drives and / or optical disks, and other types of electronic storage devices. Electronic storage device 1410 stores processor-readable instructions for causing the device to perform its operations, and stores data associated with such operations, such as data related to the 5G NR standard and other data. Network interface 1440 can implement wireless network technologies, such as 5G NR and / or other wireless network technologies.

[0209] Figure 14 The components shown are merely examples, and those skilled in the art will understand that the apparatus includes other components not shown, and may include any multiple of the components shown. Such and other embodiments are considered to be within the scope of this disclosure.

[0210] Typically, the various operations of the methods described herein can be performed by any suitable component (e.g., processor 1420 and memory 1450) capable of performing the corresponding operations. This component may include various hardware and / or (multiple) software components and / or (multiple) modules, including but not limited to… Figure 14 Components.

[0211] Other embodiments of this disclosure include the following examples.

[0212] Example 1.1. A method comprising: The core network entity of the wireless communication system sends a Non-Access Stratum (NAS) Security Mode Command (SMC) message to the User Equipment (UE). The NAS SMC message includes information about the UE's security capabilities, information for establishing a security context between the UE and the core network, and a first NAS Security Mode Message Transaction Identifier (ID). The core network entity receives a NAS security mode completion message from the UE, including the second NAS security mode message transaction ID; and Based on the condition that the comparison between the first NAS security mode message transaction ID and the second NAS security mode message transaction ID is satisfied, a security key is generated by the core network entity, wherein the security key can be used to protect the communication between the UE and the access network device of the wireless communication system.

[0213] Example 1.2. According to the method of Example 1.1, the generation of the security key is also based on the matching between the second NAS security mode message transaction ID in the NAS security mode completion message and the first NAS security mode message transaction ID in the NAS SMC message.

[0214] Example 1.3. Following the method of Example 1.1 or Example 1.2, where: The first NAS security mode message transaction ID in the NAS SMC message includes: the first NAS ID specific to the transmission of the NAS SMC message, and The second NAS security mode message transaction ID in the NAS security mode completion message includes the second NAS ID.

[0215] Example 1.4. Following the method of Example 1.1 or Example 1.2, where: The first NAS security mode message transaction ID in the NAS SMC message includes a first bit diagram, which indicates the number of retransmissions for the NASSMC message. The second NAS security mode message transaction ID in the NAS security mode completion message includes the second bitmap.

[0216] Example 1.5. Based on the method of Example 1.1 or Example 1.2, where: The first NAS security mode message transaction ID in the NAS SMC message corresponds to the NAS downlink message sequence number, and The second NAS security mode message transaction ID in the NAS security mode completion message corresponds to the NAS uplink message sequence number.

[0217] Example 1.6. The method of any one of Examples 1.1 to 1.4, wherein the NAS SMC message is sent based on the expiration of the retransmission timer.

[0218] Example 1.7. Following the method in Example 1.6, it also includes: The core network entity generates the first NAS security mode message transaction ID based on the expiration of the retransmission timer.

[0219] Example 1.8. The method according to any one of Examples 1.1 through 1.7 also includes: The core network entity receives from the UE a NAS security mode completion message, which includes the transaction ID of the third NAS security mode message; and If the comparison between the first NAS security mode message transaction ID and the third NAS security mode message transaction ID fails to meet the conditions, the core network entity will continue to monitor the NAS security mode completed message without generating a security key.

[0220] Example 1.9. Following the method in Example 1.8, it also includes: The comparison between the message transaction ID of the first NAS security mode and the message transaction ID of the third NAS security mode failed to meet the conditions, so the retransmission timer was maintained by the core network entity.

[0221] Example 1.10. The method according to any one of Examples 1.1 to 1.9 also includes: The core network entity receives a registration request message from the UE. The registration request message includes an indication of whether the UE supports the NAS security mode message transaction identifier.

[0222] Example 2.1. A method comprising: The user equipment (UE) receives a Non-Access Stratum (NAS) Security Mode Command (SMC) message from the core network entity of the core network of the wireless communication system. The NAS SMC message includes information about the UE's security capabilities, integrity key information, and a first NAS security mode message transaction identifier (ID). The UE generates a second NAS security mode message transaction ID based on the first NAS security mode message transaction ID; and The UE sends a NAS security mode completion message, which includes the second NAS security mode message transaction ID, to the core network entity.

[0223] Example 2.2. According to the method of Example 2.1, the first NAS security mode message transaction ID in the NAS SMC message includes the NAS ID specific to the transmission of the NAS SMC message.

[0224] Example 2.3. Following the method in Example 2.2, the generation of the second NAS security mode message transaction ID includes: The UE sets the second NAS security mode message transaction ID based on the NAS ID in the NAS SMC message.

[0225] Example 2.4. According to the method of Example 2.1, the first NAS security mode message transaction ID in the NAS SMC message includes an indication of the number of retransmissions associated with the NAS SMC message.

[0226] Example 2.5. Following the method in Example 2.1, the process for generating the second NAS security mode message transaction ID includes: The UE sets the second NAS security mode message transaction ID based on the number of retransmissions associated with the NAS SMC message.

[0227] Example 2.6. The method according to any one of Examples 2.1 to 2.5 also includes: The UE sends a registration request message to the core network entity. The registration request message includes an indication of whether the UE supports the NAS security mode message transaction identifier.

[0228] Example 3.1. An apparatus comprising: At least one processor; and At least one memory stores instructions that, when executed by a processor, cause the device to perform at least the following: The core network entity of the wireless communication system sends a Non-Access Stratum (NAS) Security Mode Command (SMC) message to the User Equipment (UE). The NAS SMC message includes information about the UE's security capabilities, information for establishing a security context between the UE and the core network, and a first NAS Security Mode Message Transaction Identifier (ID). The core network entity receives a NAS security mode completion message from the UE, including the second NAS security mode message transaction ID; and Based on the condition that the comparison between the first NAS security mode message transaction ID and the second NAS security mode message transaction ID is satisfied, a security key is generated by the core network entity, wherein the security key can be used to protect the communication between the UE and the access network device of the wireless communication system.

[0229] Example 3.2. The apparatus according to Example 3.1, wherein the generation of the security key is further based on the matching between the second NAS security mode message transaction ID in the NAS security mode completion message and the first NAS security mode message transaction ID in the NAS SMC message.

[0230] Example 3.3. An apparatus according to Example 3.1 or Example 3.2, wherein: The first NAS security mode message transaction ID in the NAS SMC message includes the first NAS ID specific to the transmission of the NAS SMC message, and The second NAS security mode message transaction ID in the NAS security mode completion message includes the second NAS ID.

[0231] Example 3.4. An apparatus according to Example 3.1 or Example 3.2, wherein: The first NAS security mode message transaction ID in the NAS SMC message includes a first bit diagram, which indicates the number of retransmissions for the NASSMC message. The second NAS security mode message transaction ID in the NAS security mode completion message includes the second bitmap.

[0232] Example 3.5. An apparatus according to Example 3.1 or Example 3.2, wherein: The first NAS security mode message transaction ID in the NAS SMC message corresponds to the NAS downlink message sequence number, and The second NAS security mode message transaction ID in the NAS security mode completion message corresponds to the NAS uplink message sequence number.

[0233] Example 3.6. An apparatus according to any one of Examples 3.1 to 3.4, wherein the NAS SMC message is sent based on the expiration of the retransmission timer.

[0234] Example 3.7. The apparatus according to Example 3.6 further includes: The core network entity generates the first NAS security mode message transaction ID based on the expiration of the retransmission timer.

[0235] Example 3.8. The apparatus according to any one of Examples 3.1 to 3.7 further includes: The core network entity receives from the UE a NAS security mode completion message, which includes the transaction ID of the third NAS security mode message; and If the comparison between the first NAS security mode message transaction ID and the third NAS security mode message transaction ID fails to meet the conditions, the core network entity will continue to monitor the NAS security mode completed message without generating a security key.

[0236] Example 3.9. The apparatus according to Example 3.8 further includes: The comparison between the message transaction ID of the first NAS security mode and the message transaction ID of the third NAS security mode failed to meet the conditions, so the retransmission timer was maintained by the core network entity.

[0237] Example 3.10. The apparatus according to any one of Examples 3.1 to 3.9 further includes: The core network entity receives a registration request message from the UE. The registration request message includes an indication of whether the UE supports the NAS security mode message transaction identifier.

[0238] Example 4.1. A user equipment (UE) includes: At least one processor; and At least one memory stores instructions that, when executed by a processor, cause the device to perform at least the following: The user equipment (UE) receives a Non-Access Stratum (NAS) Security Mode Command (SMC) message from the core network entity of the core network of the wireless communication system. The NAS SMC message includes information about the UE's security capabilities, integrity key information, and a first NAS security mode message transaction identifier (ID). The UE generates a second NAS security mode message transaction ID based on the first NAS security mode message transaction ID; and The UE sends a NAS security mode completion message, which includes the second NAS security mode message transaction ID, to the core network entity.

[0239] Example 4.2. According to the UE of Example 4.1, the first NAS security mode message transaction ID in the NAS SMC message includes the NAS ID specific to the transmission of the NAS SMC message.

[0240] Example 4.3. According to the UE in Example 4.2, the transaction ID for generating the second NAS security mode message includes: The UE sets the second NAS security mode message transaction ID based on the NAS ID in the NAS SMC message.

[0241] Example 4.4. According to the UE in Example 4.1, the first NAS security mode message transaction ID in the NAS SMC message includes an indication of the number of retransmissions associated with the NAS SMC message.

[0242] Example 4.5. Based on the UE in Example 4.1, the transaction ID for generating the second NAS security mode message includes: The UE sets the second NAS security mode message transaction ID based on the number of retransmissions associated with the NAS SMC message.

[0243] Example 4.6. The UE based on any one of Examples 4.1 to 4.5 also includes: The UE sends a registration request message to the core network entity. The registration request message includes an indication of whether the UE supports the NAS security mode message transaction identifier.

[0244] Example 5.1. An apparatus comprising: A component for sending a Non-Access Stratum (NAS) Security Mode Command (SMC) message from a core network entity of a wireless communication system to a user equipment (UE). The NAS SMC message includes information about the UE's security capabilities, information for establishing a security context between the UE and the core network, and a first NAS security mode message transaction identifier (ID). A component for receiving a NAS security mode completion message, including a second NAS security mode message transaction ID, from a UE by a core network entity; and A component for generating a security key by a core network entity based on a comparison condition between a first NAS security mode message transaction ID and a second NAS security mode message transaction ID, wherein the security key can be used to protect communication between the UE and the access network device of the wireless communication system.

[0245] Example 5.2. The apparatus according to Example 5.1, wherein the generation of the security key is further based on the matching between the second NAS security mode message transaction ID in the NAS security mode completion message and the first NAS security mode message transaction ID in the NAS SMC message.

[0246] Example 5.3. An apparatus according to Example 5.1 or Example 5.2, wherein: The first NAS security mode message transaction ID in the NAS SMC message includes the first NAS ID specific to the transmission of the NAS SMC message, and The second NAS security mode message transaction ID in the NAS security mode completion message includes the second NAS ID.

[0247] Example 5.4. An apparatus according to Example 5.1 or Example 5.2, wherein: The first NAS security mode message transaction ID in the NAS SMC message includes a first bit diagram, which indicates the number of retransmissions for the NASSMC message. The second NAS security mode message transaction ID in the NAS security mode completion message includes the second bitmap.

[0248] Example 5.5. An apparatus according to Example 5.1 or Example 5.2, wherein: The first NAS security mode message transaction ID in the NAS SMC message corresponds to the NAS downlink message sequence number, and The second NAS security mode message transaction ID in the NAS security mode completion message corresponds to the NAS uplink message sequence number.

[0249] Example 5.6. An apparatus according to any one of Examples 5.1 to 5.4, wherein the NAS SMC message is sent based on the expiration of the retransmission timer.

[0250] Example 5.7. The apparatus according to Example 5.6 further includes: A component used by core network entities to generate the first NAS security mode message transaction ID based on the expiration of the retransmission timer.

[0251] Example 5.8. The apparatus according to any one of Examples 5.1 to 5.7 further includes: A component for receiving, by a core network entity, a NAS security mode completion message, including a third NAS security mode message transaction ID, from a UE; and A component used by a core network entity to continue monitoring NAS security mode completion messages without generating a security key if the comparison between the first NAS security mode message transaction ID and the third NAS security mode message transaction ID fails to meet the conditions.

[0252] Example 5.9. The apparatus according to Example 5.8 further includes: A component used to maintain a retransmission timer when the comparison between the first NAS security mode message transaction ID and the third NAS security mode message transaction ID by a core network entity fails to meet the conditions.

[0253] Example 5.10. The apparatus according to any one of Examples 5.1 to 5.9 further includes: This component is used by the core network entity to receive registration request messages from the UE. The registration request message includes an indication of whether the UE supports NAS security mode message transaction identifiers.

[0254] Example 6.1. A user equipment (UE) includes: A component for receiving Non-Access Stratum (NAS) Security Mode Command (SMC) messages from a core network entity of the core network of a wireless communication system by a user equipment (UE). The NAS SMC message includes information about the UE's security capabilities, integrity key information, and a first NAS security mode message transaction identifier (ID). A component for generating a second NAS security mode message transaction ID by the UE based on a first NAS security mode message transaction ID; and A component used by the UE to send a NAS security mode completion message, including the second NAS security mode message transaction ID, to a core network entity.

[0255] Example 6.2. According to the UE of Example 6.1, the first NAS security mode message transaction ID in the NAS SMC message includes the NAS ID specific to the transmission of the NAS SMC message.

[0256] Example 6.3. According to the UE in Example 6.2, the transaction ID for generating the second NAS security mode message includes: A component used by the UE to set the second NAS security mode message transaction ID based on the NAS ID in the NAS SMC message.

[0257] Example 6.4. According to the UE of Example 6.1, the first NAS security mode message transaction ID in the NAS SMC message includes an indication of the number of retransmissions associated with the NAS SMC message.

[0258] Example 6.5. Based on the UE in Example 6.1, the transaction ID for generating the second NAS security mode message includes: A component used by the UE to set the second NAS security mode message transaction ID based on the number of retransmissions associated with the NAS SMC message.

[0259] Example 6.6. The UE according to any one of Examples 6.1 to 6.5 also includes: This component is used by the UE to send a registration request message to the core network entity. The registration request message includes an indication of whether the UE supports the NAS security mode message transaction identifier.

[0260] Example 7. A non-transitory processor-readable medium comprising program code that, when executed by one or more processors, causes the one or more processors to perform at least one of the methods according to any one of Examples 1.1 to 1.10.

[0261] Example 8. A non-transitory processor-readable medium comprising program code that, when executed by one or more processors, causes the one or more processors to perform at least one of the methods according to any one of Examples 2.1 to 2.6.

[0262] The embodiments and aspects disclosed herein are examples of this disclosure and may be embodied in various forms. For example, although some embodiments herein are described as separate embodiments, each embodiment herein may be combined with one or more other embodiments herein. The specific structural and functional details disclosed herein should not be construed as limiting, but rather serve as the basis for the claims and as a representative basis for teaching those skilled in the art to use this disclosure in various ways in virtually any suitably detailed structure. Throughout the description of the drawings, the same reference numerals may refer to similar or identical elements.

[0263] According to this disclosure, the phrases “in one aspect,” “in multiple aspects,” “in all aspects,” “in some aspects,” or “in other aspects” can each refer to one or more of the same or different aspects. The phrase “multiple aspects” can refer to two or more.

[0264] According to this disclosure, the phrases “in one embodiment,” “in multiple embodiments,” “in various embodiments,” “in some embodiments,” or “in other embodiments” can each refer to one or more of the same or different embodiments. A phrase of the form “A or B” means “(A), (B), or (A and B).” A phrase of the form “at least one of A, B, or C” means “(A); (B); (C); (A and B); (A and C); (B and C); or (A, B, and C).”

[0265] Any method, program, algorithm, or code described herein can be translated into or represented in a programming language or computer program. The terms "programming language" and "computer program" as used herein each include any language used to specify computer instructions, and include (but are not limited to) the following languages ​​and their derivatives: assembly language, Basic, batch files, BCPL, C, C+, C++, Delphi, Fortran, Java, JavaScript, machine code, operating system command languages, Pascal, Perl, PL1, Python, scripting languages, Visual Basic, meta-languages ​​that specify the program itself, and all first-, second-, third-, fourth-, fifth-, or later computer languages. Databases and other data schemas, and any other meta-languages, are also included. No distinction is made between interpreted, compiled, or both compiled and interpreted languages. No distinction is made between compiled and source code versions of a program. Therefore, if a programming language can exist in more than one state (such as source, compilation, object, or link), a reference to a program is a reference to any and all such states. A reference to a program can encompass the actual instructions and / or the intent of those instructions.

[0266] While various aspects of this disclosure are shown in the accompanying drawings, they are not intended to limit the disclosure thereto, as the scope of this disclosure should be as broad as possible, and the specification should be read in the same manner. Therefore, the above description should not be construed as limiting, but merely as examples of specific aspects. Those skilled in the art will be able to conceive of other modifications within the scope and spirit of the appended claims.

Claims

1. A method comprising: The core network entity of the core network of the wireless communication system sends a Non-Access Stratum (NAS) Security Mode Command (SMC) message to the User Equipment (UE). The NAS SMC message includes information about the security capabilities of the UE, information for establishing a security context between the UE and the core network, and a first NAS Security Mode Message Transaction Identifier (ID). The core network entity receives a NAS security mode completion message from the UE, which includes a second NAS security mode message transaction ID. as well as Based on the condition that the comparison between the first NAS security mode message transaction ID and the second NAS security mode message transaction ID meets the condition, the core network entity generates a security key, wherein the security key can be used to protect the communication between the UE and the access network device of the wireless communication system.

2. The method of claim 1, wherein generating the security key is further based on matching the second NAS security mode message transaction ID in the NAS security mode completion message with the first NAS security mode message transaction ID in the NAS SMC message.

3. The method according to claim 1 or claim 2, wherein: The first NAS security mode message transaction ID in the NAS SMC message includes a first NAS ID specific to the transmission of the NAS SMC message, and The second NAS security mode message transaction ID in the NAS security mode completion message includes the second NAS ID.

4. The method according to claim 1 or claim 2, wherein: The first NAS security mode message transaction ID in the NAS SMC message includes a first bit map, which includes an indication of the number of retransmissions for the NAS SMC message. The second NAS security mode message transaction ID in the NAS security mode completion message includes a second bitmap.

5. The method according to claim 1 or claim 2, wherein: The first NAS security mode message transaction ID in the NAS SMC message corresponds to the NAS downlink message sequence number, and The second NAS security mode message transaction ID in the NAS security mode completion message corresponds to the NAS uplink message sequence number.

6. The method according to any one of claims 1 to 4, wherein the NAS SMC message is sent based on the expiration of the retransmission timer.

7. The method according to claim 6, further comprising: The core network entity generates the first NAS security mode message transaction ID based on the expiration of the retransmission timer.

8. The method according to any one of claims 1 to 7, further comprising: The core network entity receives from the UE another NAS security mode completion message, which includes the third NAS security mode message transaction ID; as well as If the comparison between the first NAS security mode message transaction ID and the third NAS security mode message transaction ID fails to meet the condition, the core network entity will continue to monitor the NAS security mode completion message without generating a security key.

9. The method according to claim 8, further comprising: If the comparison between the first NAS security mode message transaction ID and the third NAS security mode message transaction ID fails to meet the condition, the retransmission timer is maintained by the core network entity.

10. The method according to any one of claims 1 to 9, further comprising: The core network entity receives a registration request message from the UE, the registration request message including an indication of whether the UE supports NAS security mode message transaction identifier.

11. A method comprising: The user equipment (UE) receives a Non-Access Stratum (NAS) Security Mode Command (SMC) message from the core network entity of the core network of the wireless communication system. The NAS SMC message includes information about the UE's security capabilities, integrity key information, and a first NAS security mode message transaction identifier (ID). The UE generates a second NAS security mode message transaction ID based on the first NAS security mode message transaction ID; as well as The UE sends a NAS security mode completion message, including the second NAS security mode message transaction ID, to the core network entity.

12. The method of claim 11, wherein the first NAS security mode message transaction ID in the NAS SMC message includes a NAS ID specific to the transmission of the NAS SMC message.

13. The method of claim 12, wherein generating the second NAS security mode message transaction ID comprises: The UE sets the second NAS security mode message transaction ID based on the NAS ID in the NAS SMC message.

14. The method of claim 11, wherein the first NAS security mode message transaction ID in the NAS SMC message includes an indication of the number of retransmissions associated with the NAS SMC message.

15. The method of claim 14, wherein generating the second NAS security mode message transaction ID comprises: The UE sets the second NAS security mode message transaction ID based on the number of retransmissions associated with the NAS SMC message.

16. The method according to any one of claims 11 to 15, further comprising: The UE sends a registration request message to the core network entity, the registration request message including an indication of whether the UE supports NAS security mode message transaction identifier.

17. An apparatus comprising: At least one processor; as well as At least one memory stores instructions that, when executed by the processor, cause the apparatus to perform at least the method according to any one of claims 1 to 10.

18. A user equipment (UE), comprising: At least one processor; as well as At least one memory stores instructions that, when executed by the processor, cause the UE to perform at least the method according to any one of claims 11 to 16.

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