Methods of protecting medium access control control elements

Abstract

Methods and devices in a wireless communication network protect Medium Access Control, MAC, control elements, CEs. A method (1500) for wireless communication performed by a radio access network, RAN, node (104), includes transmitting (1570), to a user equipment, UE, (102) a first message indicating a secure algorithm to be used to protect a MAC CE, and communicating (1572), with the UE, a security protected MAC CE based on the secure algorithm. The secure algorithm may include a ciphering algorithm and / or an integrity algorithm and may use MAC CE specific inputs.

Description

Patent Application Attorney Docket Number 0683-124-WOMETHODS OF PROTECTING MEDIUM ACCESS CONTROL CONTROL ELEMENTSFIELD OF THE DISCLOSURE

[0001] This document generally describes methods and devices operating in wireless communication systems such as (but not limited to) the ones described in fifth generation (5G) standard documents, known as Third Generation Partnership Project (3GPP) communication systems. This disclosure relates to wireless communications and, more particularly, to enabling secure transmissions of Medium Access Control (MAC) control elements (CEs).BACKGROUND

[0002] This background description is provided for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.

[0003] The 3GPP has standardized the 5G radio interface, known as new radio (NR). The 5G NR protocol stack incorporates a physical layer, a Medium Access Control (MAC) layer, a Radio Link Control (RLC) layer, a Packet Data Convergence Protocol (PDCP) layer, and Radio Resource Control (RRC). Within the MAC layer, 3GPP defines MAC Control Elements (CEs), carrying different types of control information. Each MAC CE is associated with a corresponding MAC CE subheader, which includes a logical channel identity (LCID) that identifies the respective MAC CE. The 5G NR currently transmits MAC CEs without security protection, which is a security vulnerability threat.

[0004] Quantum computing and artificial intelligence (Al) pose a significant and evolving security threat to communication networks. The International Telecommunication Union (ITU) has established a framework for the development ofPatent Application Attorney Docket Number 0683-124-WOstandards for sixth generation (6G) radio interface technologies. The 6G mobile systems will have deeply integrated Al capabilities. The underlying infrastructure must facilitate agile development and deployment of distributed applications and network functions. Critically, services for data and compute acceleration, with end-to-end performance guarantees, are to be provisioned throughout the 6G network.

[0005] Quantum computers, leveraging their capacity to rapidly solve complex mathematical problems, may compromise existing communication protocols.Concurrently, Al's adaptive learning capabilities enable the development of sophisticated attack vectors capable of circumventing conventional detection mechanisms. For instance, Al-driven attacks could autonomously identify and exploit subtle network vulnerabilities.

[0006] The synergy of quantum computing and Al creates a scenario in which attacks may be not only more potent but also increasingly difficult to detect and mitigate due to their real-time adaptive nature. Thus, transmitting MAC CEs without security protection leaves an unacceptable large likelihood of success for malicious attack.

[0007] Counterfeit or spoofed MAC CEs could be communicated resulting in a number of issues such as inadequate signal strength, connection failure, poor signal quality, or even terminated connections. For example, a forged Layer 1 / Layer 2 Triggered Mobility (LTM) cell switch command could be transmitted to a UE, directing it to connect to an LTM candidate cell with inadequate signal strength. This could result in connection failure. Similarly, a fraudulent Transmission Configuration Indicator (TCI) state activation or deactivation command could force a UE to utilize a TCI state with poor signal quality, impeding communication. Furthermore, a fabricated Secondary Cell (SCell) deactivation command could be transmitted to a UE, abruptly terminating communication on the SCell. Therefore, it is desirable to protect MAC CEs as they are communicated between RAN nodes and UEs.Patent Application Attorney Docket Number 0683-124-WOSUMMARY

[0008] The above discussed vulnerability of conventional communication networks is overcome when a user equipment, UE, and a radio access network, RAN, node, e.g., a base station, BS, communicate MAC CEs that are security-protected.

[0009] In one embodiment, a method for wireless communication is performed by a RAN node and includes transmitting, to a UE, a first message indicating a secure algorithm to be used to protect a MAC CE and communicating, with the UE, a security protected MAC CE based on the secure algorithm. The communicating includes transmitting, to the UE, the security protected MAC CE and / or receiving, from the UE, the security protected MAC CE. The method may include applying the secure algorithm to a security protected MAC CE received from the UE, and / or to a MAC CE to be transmitted to the UE.

[0010] In another embodiment, a method for wireless communication is performed by a UE and includes receiving, from a RAN node, a first message indicating a secure algorithm to be used to protect a MAC CE and communicating, with the RAN node, a security protected MAC CE based on the secure algorithm. The communicating includes transmitting, to the RAN node, the security protected MAC CE and / or receiving, from the RAN node, a security protected MAC CE. The method may include applying the secure algorithm to the security protected MAC CE received from the RAN node, or to a MAC CE to be transmitted to the RAN node.

[0011] In some implementations, the secure algorithm includes at least one of a ciphering algorithm or an integrity algorithm. The first message may be a security mode command and a second message sent in response to the first message can be a security mode complete.BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate one or more embodiments and, together with the description, explain these embodiments.Patent Application Attorney Docket Number 0683-124-WO

[0013] Fig. 1 is a block diagram of an example system having one or more RAN nodes and a UE that are configured to perform methods for securely exchanging MAC CEs.

[0014] Fig. 2 is a block diagram of an example protocol stack for UEs and RAN nodes as shown in Fig. 1.

[0015] Fig. 3A is a signal diagram illustrating a scenario in which a UE and a RAN node apply methods for securely communicating MAC CEs.

[0016] Fig. 3B is another signal diagram illustrating another scenario in which a UE and a RAN node apply methods for securely communicating MAC CEs.

[0017] Fig. 4A illustrates using an integrity algorithm for integrity protection and integrity check of data according to an embodiment.

[0018] Fig. 4B illustrates using an integrity algorithm for integrity protection and integrity check of MAC CE according to an embodiment.

[0019] Fig. 5A illustrates using a ciphering algorithm for encrypting and decrypting data according to an embodiment.

[0020] Fig. 5B illustrates using a ciphering algorithm for encrypting and decrypting MAC CEs according to an embodiment.

[0021] Fig. 6A illustrates a MAC Protocol Data Unit (PDU) having one or more MAC subPDUs with a security protected MAC CE according to an embodiment.

[0022] Fig. 6B illustrates a MAC PDU having one or more MAC subPDUs with a security-protected MAC CE or a non-security protected MAC CE according to an embodiment.

[0023] Fig. 6C illustrates a MAC PDU with one or more MAC subPDUs having security protection according to an embodiment.

[0024] Fig. 6D illustrates a MAC PDU with one or more MAC subPDUs having security protection according to an embodiment.Patent Application Attorney Docket Number 0683-124-WO

[0025] Fig. 7A is a flowchart of a method of a security mode procedure performed by a UE according to an embodiment.

[0026] Fig. 7B is a flowchart of another method of a security mode procedure performed by a UE according to an embodiment.

[0027] Fig. 8A is a flowchart of a method of a security mode procedure performed by a RAN node according to an embodiment.

[0028] Fig. 8B is a flowchart of another method of a security mode procedure performed by a RAN node according to an embodiment.

[0029] Fig. 9A is a flowchart of a method of activating security protection performed by a UE according to an embodiment.

[0030] Fig. 9B is a flowchart of another method of activating security protection performed by a UE according to an embodiment.

[0031] Fig. 10A is a flowchart of a method of activating security protection performed by a RAN node according to an embodiment.

[0032] Fig. 10B is a flowchart of another method of activating security protection performed by a RAN node according to an embodiment.

[0033] Fig. 11 A is a flowchart of a method of activating security protection for communicating MAC CEs performed by a UE according to an embodiment.

[0034] Fig. 11 B is a flowchart of another method of activating security protection for communicating MAC CEs performed by a UE according to an embodiment.

[0035] Fig. 12A is a flowchart of a method of activating security protection for communicating MAC CEs performed by a RAN node according to an embodiment.

[0036] Fig. 12B is a flowchart of another method of activating security protection for communicating MAC CEs performed by a RAN node according to an embodiment.

[0037] Fig. 13A is a flowchart of a method of receiving a security mode command performed by a UE according to an embodiment.Patent Application Attorney Docket Number 0683-124-WO

[0038] Fig. 13B is a flowchart of another method of receiving a security mode command performed by a UE according to an embodiment.

[0039] Fig. 13C is a flowchart of yet another method of receiving a security mode command performed by a UE according to an embodiment.

[0040] Fig. 14A is a flowchart of a method of transmitting a security mode command performed by a RAN node according to an embodiment.

[0041] Fig. 14B is a flowchart of another method of transmitting a security mode command performed by a RAN node according to an embodiment.

[0042] Fig. 15 is a flowchart of a method for wireless communication performed by a RAN node according to an embodiment.

[0043] Fig. 16 is a flowchart of a method for wireless communication performed by a UE according to an embodiment.Patent Application Attorney Docket Number 0683-124-WODETAILED DESCRIPTION

[0044] Methods and devices described in this section embody techniques related to wireless communications and enabling secure transmissions of MAC CEs.

[0045] The embodiment descriptions in this section refer to the accompanying drawings. The same reference numbers in different drawings identify the same or similar elements. The detailed descriptions do not preclude other embodiments within the scope of the appended claims. The embodiments are not limited to the configurations described in this section but may be extended to other arrangements.

[0046] While 5G NR currently transmits MAC CEs without security protection, the potential for exploitation may increase as quantum computing and Al technologies mature. In order to overcome the vulnerability of conventional communication networks, a UE and a RAN node (e.g., a base station, BS) communicate MAC CEs that are security protected.

[0047] Fig. 1 depicts an example wireless communication system 100 in which communication devices can apply methods for securely communicating MAC CEs. The wireless communication system 100 includes a UE 102, a RAN 105 interconnecting RAN nodes such as a base station (BS) 104 and a base station 106, and a core network (CN) 110. The CN 110 may be or include an evolved packet core (EPC) 111 , a fifth generation (5G) core (5GC) 160 and / or a sixth generation (6G) core (6GC) 180, for example. The base station 104 can be an eNB supporting an S1 interface for communicating with the EPC 111, an ng-eNB supporting an NG interface for communicating with the 5GC 160, or a gNB that supports an NR radio interface as well as an NG interface for communicating with the 5GC 160. The RAN node or base station 104 can also be a 6G base station (BS) supporting the NG interface, a new NG interface, or a 6G BS-to-CN (e.g., N6G) interface for communicating with the 5GC 160 or the 6GC 180. To directly exchange messages with each other during the scenarios discussed below, the base stations 104 and 106 can support an X2, an Xn, a new Xn, or a 6G BS-to-BS (e.g., X6G) interface. Among other components, the EPC 111 typically includes at least at a Serving Gateway (SGW) 112, a Mobility Management Entity (MME) 114, and a Packet Data Network Gateway (PGW) 116. The SGW 112 is generally configured to transfer user-plane packets related to audio calls, video calls, Internet traffic, etc., and the MME 114 is configured to manage authentication,Patent Application Attorney Docket Number 0683-124-WOregistration, paging, and other related functions. The PGW 116 provides connectivity from the UE to one or more external packet data networks, e.g., an Internet network and / or an Internet Protocol (IP) Multimedia Subsystem (IMS) network. The 5GC 160 includes a User Plane Function (UPF) 162 and an Access and Mobility Management (AMF) 164, and / or a Session Management Function (SMF) 166. The UPF 162 is generally configured to transfer user-plane packets related to audio calls, video calls, Internet traffic, etc., the AMF 164 is configured to manage authentication, registration, paging, and other related functions, and the SMF 166 is configured to manage PDU sessions. The 6GC 180 includes a 6G UPF 182 and a 6G AMF 184, and / or 6G SMF 186, similar to the UPF 162, the AMF 164 and the SMF 166 with enhanced functions respectively.

[0048] As illustrated in Fig. 1, the base station 104 supports cell 124, and the base station 106 supports cell 126. The cells 124 and 126 can operate on the same carrier frequency or different carrier frequencies. For example, the cell 126 operates on DL carrier frequencies f 1 , f2 and f3 respectively. The cell 124 may operate on the DL carrier frequency f1. In cases where the cells 124 and 126 operate in a time division duplex (TDD) mode, the cells 124 and 126 operate in UL carrier frequencies same as the DL carrier frequencies. In cases where the cells 124 and 126 operate in a frequency division duplex (FDD) mode, the cells 124 and 126 operate in UL carrier frequencies different from the DL carrier frequencies. The cells 124 and 126 can partially overlap to provide seamless service continuity. Thus, while the UE 102 may move among the cells 124 and 126, the UE 102 still communicates with the CN 110 via these cells. In general, the wireless communication network 100 can include any suitable number of base stations supporting 6G cells, NR cells, and / or EUTRA cells. More particularly, the EPC 111 can be connected to any suitable number of base stations supporting EUTRA cells, while the 5GC 160 and / or the 6GC 180 can be connected to any suitable number of base stations supporting 6G cells and / or NR cells. Although the examples below refer specifically to specific CN types (EPC, 5GC, 6GC) and RAT types (6G, 5G NR and EUTRA), in general the techniques of this disclosurePatent Application Attorney Docket Number 0683-124-WOalso can apply to other suitable radio access and / or core network technologies such as seventh generation (7G) radio access and / or 7G core network.

[0049] With continued reference to Fig. 1 , the RAN node or base station 104 is equipped with processing hardware 130 that includes one or more general-purpose processors (e.g., CPUs) and a non-transitory computer-readable memory (CRM) storing instructions that the one or more general-purpose processors execute. Additionally or alternatively, the processing hardware 130 may include special-purpose processing units. According to an embodiment illustrated in Fig. 1, the processing hardware 130 includes a processor 132 to process data that the base station 104 transmits in the downlink direction, or data that the base station 104 receives in the uplink direction. The processing hardware 130 also includes a receiver 134 configured to transmit data in the downlink direction and to receive data in the uplink direction. The processing hardware 130 also includes a medium access control (MAC) control element (CE) security manager 136 configured to manage security protection for communicating one or more MAC CEs with UE(s). The processing hardware 130 also includes a data security controller 138 configured to manage security protection for data communication. The CRM (not shown) stores executable codes for the processor 132 to perform methods according to embodiments described in this section. The RAN node or base station 106 includes generally similar components.

[0050] The UE 102 is equipped with processing hardware 140 that can include one or more general-purpose processors such as CPUs and non-transitory CRM storing machine-readable instructions executable on the one or more general-purpose processors, and / or special-purpose processing units. As schematically illustrated in Fig.1 , the processing hardware 140 includes a processor 142 to prepare data that the UE 102 transmits in the uplink direction, or to process data that the UE 102 receives in the downlink direction. The processing hardware 140 also includes a transceiver 144 configured to transmit data in the uplink direction and to receive data in the downlink direction. The processing hardware 140 further includes a MAC CE security manager 146 configured to manage security protection for communicating one or more MAC CEsPatent Application Attorney Docket Number 0683-124-WOwith UE(s). The processing hardware 140 also includes a data security controller 148 configured to manage security protection for data communication.

[0051] Fig. 2 illustrates, in a simplified manner, an example protocol stack 200 according to which the UE 102 can communicate with a 6gNB 230 (i.e. , a 6G RAN node) and / or a gNB 232 (e.g., one or more of the RAN nodes or base stations 104, 106).

[0052] In the example stack 200, a NR PHY 202B provides transport channels to a NR MAC sublayer 204B, which in turn provides logical channels to a NR RLC sublayer 206B. The NR RLC sublayer 206B in turn provides data transfer services to a NR PDCP sublayer 208B. The NR PDCP sublayer 208B in turn can provide data transfer services to a Service Data Adaptation Protocol (SDAP) 210B sublayer and / or a radio resource control (RRC) sublayer (not shown in Fig. 2). Similarly, a physical layer (PHY) 202A of 6G provides transport channels to the 6G MAC sublayer 204A, which in turn provides logical channels to the 6G RLC sublayer 206A. The 6G RLC sublayer 206A in turn provides RLC channels to a 6G PDCP sublayer 208A. The 6G PDCP sublayer 208A in turn can provide data transfer services to a 6G Service Data Adaptation Protocol (SDAP) sublayer 210A or a 6G radio resource control (RRC) sublayer (not shown in Fig. 2). In some implementations, the 6G SDAP sublayer 210A can be omitted. In such cases, the PDCP sublayer 208A may support functionalities of the SDAP sublayer 210A. The UE 102, in some implementations, supports both the 6G and the NR stack as shown in Fig. 2, to support handover between 6G and NR base stations and / or to support DC over 6G and NR interfaces.

[0053] The 6G PDCP sublayer 208A and the NR PDCP sublayer 208B receive packets (e.g., from an Internet Protocol (IP) layer, layered directly or indirectly over the PDCP layer 208A or 208B) that can be referred to as service data units (SDUs), and output packets (e.g., to the RLC layer 206A or 206B) that can be referred to as protocol data units (PDUs). Except where the difference between SDUs and PDUs is relevant, this disclosure for simplicity refers to both SDUs and PDUs as “packets.”Patent Application Attorney Docket Number 0683-124-WO

[0054] On a control plane, the 6G PDCP sublayer 208A and the NR PDCP sublayer 208B can provide signaling radio bearers (SRBs) or RRC sublayer (not shown in Fig. 2) to exchange RRC messages or non-access-stratum (NAS) messages, for example. On a user plane, the 6G PDCP sublayer 208A and the NR PDCP sublayer 208B can provide Data Radio Bearers (DRBs) to support data exchange. Data exchanged on the 6G PDCP sublayer 208A and NR PDCP sublayer 208B can be SDAP PDUs, Internet Protocol (IP) packets, or Ethernet packets.

[0055] Next, several example scenarios in which the UE 102 and the BS 104 operating in the system of Fig. 1 communicate data and MAC CEs. Generally speaking, events in Figs. 3A-3B, 4A-5B, and 9A-14C that are similar are labeled with similar reference numbers (e.g., event 394 of Figs. 3A and 3B are similar to event 494 of Figs.4A and 4B, event 594 of Figs. 5A and 5B, event 1394 of Figs. 13A-13C, and event 1494 of Figs. 14A-14C; event 316A of Fig. 3A is similar to event 316B of Fig. 3B, event 416A of Fig. 4A, event 416B of Fig. 4B, event 516A of Fig. 5A, event 516B of Fig. 5B, event 916 of Figs. 9A, 9B, 11 A, 11B, event 1316A of Fig. 13A, event 1316B of Fig. 13B, event 1416A of Fig. 14A, and event 1416B of Fig. 14B; etc.), with differences discussed below where appropriate. With the exception of the differences shown in the figures and discussed below, any of the alternative implementations discussed with respect to a particular event (e.g., for messaging and processing) may apply to events labeled with similar reference numbers in other figures.

[0056] Referring first to Fig. 3A, in a scenario 300A, the UE 102 initially performs a connection establishment procedure with the base station (BS) 104. As a result of the procedure 390, the UE 102 and the BS 104 establish a connection with each other. In some implementations, the connection includes a signaling radio bearer (SRB). For example, the SRB is a SRB1. In some implementations, the UE 102 may transition to a connected state after (e.g., in response to) the connection establishment procedure. In some implementations, during or after the procedure 390, the UE 102 receives 302 one or more DL MAC PDUs from the BS 104 and / or transmits 304 one or more UL MAC PDUs to the BS 104. In some implementations, some of the one or more DL MAC PDUs may include at least one non-security-protected DL MAC CE. In somePatent Application Attorney Docket Number 0683-124-WOimplementations, some of the one or more UL MAC PDUs may include at least one non-security-protected UL MAC CE. In some implementations, some of the one or more DL MAC PDUs may include at least one non-security-protected DL data packet(s). In some implementations, the DL data packet(s) includes at least one user-plane (UP) data packet and / or at least one control-plane (CP) message (e.g., DL RRC message or DL NAS message). In other implementations, the DL data packet(s) exclude UP data packets. In some implementations, some of the one or more UL MAC PDUs may include at least one non-security-protected UL data packet(s). In some implementations, the UL data packet(s) includes at least one UP data packet and / or at least one CP message (e.g., UL RRC message or UL NAS message). In other implementations, the UL data packet(s) exclude UP data packets.

[0057] The UE 102 transmits a connection request message to the BS 104 to initiate the connection establishment procedure. In response, the BS 104 transmits a connection establishment message to the UE 102 to set up the connection. In response, the UE 102 may transmit a connection complete message to the BS 104 to complete the connection establishment procedure. In some implementations, the connection establishment procedure is an RRC connection establishment procedure. In some implementations, the connection request message, the connection establishment message, and the connection complete message are an RRC setup request message, an RRC setup message, and an RRC setup complete message, respectively.

[0058] After establishing the connection (e.g., transmitting the connection establishment message or receiving the connection complete message) with the UE 102, the BS 104 determines 306 to activate or activates 306 security protection for communicating data (e.g., CP data and / or UP data) with the UE 102. In response to determining 306 to activate or activating 306 security protection, the BS 104 applies security protection to a security mode command message to generate a respective security-protected security mode command message. The BS 104 then transmits 308 the security-protected security mode command message to the UE 102. In some implementations, the BS 104 transmits 308 a first DL PDU to the UE 102, including the security-protected security mode command message. In response to receiving 308 thePatent Application Attorney Docket Number 0683-124-WOsecurity mode command message, the UE 102 activates 310 security protection for communicating data packets (e.g., CP data and / or UP data) with the BS 104. After activating 310 security protection and in response to the security mode command message, the UE 102 applies security protection to a security mode complete message to obtain a security-protected security mode complete message. The UE 102 then transmits 312 the security-protected security mode complete message to the BS 104. In some implementations, the UE 102 transmits 312 a first UL PDU to the BS 104, including the security-protected security mode complete message. Steps 308, 310, and 312 pertain to a security mode procedure 392.

[0059] In some implementations, after activating 306 security protection, the BS 104 applies a security check to the received security mode complete message. After activating 310 security protection, the UE 102 communicates 394 security-protected data packets with the BS 104. Similarly, after activating 306 security protection and / or receiving the security mode complete message, the BS 104 communicates 394 security-protected data packets with the UE 102. In some implementations, the data packets include CP data packets (e.g., UL RRC message, DL RRC messages, UL NAS messages, and / or DL NAS messages) and / or UP data packets (e.g., Internet Protocol packets and / or Ethernet protocol packets).

[0060] In some implementations, the security protection includes integrity protection and check and / or encryption and decryption. Here, “encryption” and “decryption” can be replaced by “ciphering” and “deciphering” respectively. In some implementations, the security mode command message configures an integrity algorithm (i.e., a first integrity algorithm) for integrity protection and check. In some implementations, the UE 102 obtains a first integrity key for integrity protection and check. In some implementations, the UE 102 derives the first integrity key based on a first base key, an identity or identifier (ID) of the integrity algorithm, a key derivation function, and / or one or more additional parameters. In some implementations, the UE 102 obtains the one or more additional parameters from a Universal Subscriber Identity Module (USIM). In other implementations, the UE 102 receives a DL NAS message configuring, indicating or including the one or more additional parameters from a CNPatent Application Attorney Docket Number 0683-124-WOnode (e.g., the AMF 164 or 184) via a BS (e.g., the BS 104 or 106). In yet other implementations, the UE 102 derives the one or more additional parameters based on at least one parameter in a DL NAS message received from the CN node via the BS. In yet other implementations, the UE 102 derives the one or more additional parameters based on at least one parameter obtained from the USIM. In yet other implementations, the UE 102 receives the one or more additional parameters from the BS 104. In some implementations, the first base key is a first key for the BS 104 (KBS). In some implementations, the first KBS is a K9NB or a KegNB. In some implementations, the UE 102 derives the first base key from a first key for CN (KCN). In some implementations, the first KCN is a KAMF or a KegAMF.

[0061] In some implementations, the BS 104 obtains a first integrity key (i.e., same as the first integrity key obtained by the UE 102). In some implementations, the BS 104 derives the first integrity key (i.e., same as the first integrity key derived by the UE 102) using a first base key (i.e., same as the first base key used by the UE 102 to derive the first integrity key of the UE 102), a key derivation function (same as the key derivation function used by the UE 102), the ID of the integrity algorithm, and / or one or more additional parameters (i.e., same as the one or more additional parameters used by the UE 102 to derive the first integrity key of the UE 102). In some implementations, the BS 104 receives the one or more additional parameters in a CN-to-BS message from a CN node (e.g., AMF such as AMF 164 or 184). In other implementations, the BS 104 generates the one or more additional parameters. In some implementations, the one or more additional parameters include security capabilities of the UE 102, indicating support of one or more integrity algorithms. The one or more integrity algorithms include the first integrity algorithm and / or the second integrity algorithm described above or below. In some implementations, the BS 104 receives the first base key from the CN node. The CN node generates the first base key from the first KCN.

[0062] In some implementations, the BS 104 applies integrity protection to the security mode command message after or in response to event 306. In some implementations, the BS 104 generates a first message authentication code for integrity (MAC-I) for protecting security of the security mode command message. The BS 104Patent Application Attorney Docket Number 0683-124-WOmay generate the first MAC-1 using the first integrity key, the integrity algorithm, and / or additional parameter(s) as described for Fig. 4A. For example, the additional parameter(s) include(s) COUNT, BEARER, and / or DIRECTION as shown in Fig. 4A. As an example, the COUNT may be associated with the security mode command message. For example, the COUNT consists of a hyper frame number (HFN) and a PDCP sequence number. The BS 104 assigns the PDCP sequence number for the security mode command message and includes the PDCP sequence number in the first DL PDU. The BEARER may be a bearer identity (i.e. , a value) identifying a bearer used by the BS 104 to transmit the security mode command message. For example, the bearer is a SRB1 and the BEARER is 1. The DIRECTION may be associated with downlink. For example, the DIRECTION (e.g., a bit) is set to 1 for downlink. The BS 104 generates the first DL PDU including the security mode command message and the first MAC-I and transmits 308 the first DL PDU to the UE 102. The first DL PDU may be a PDCP PDU. Upon receiving 308 the first DL PDU, the UE 102 retrieves the first MAC-I from the first DL PDU. The UE 102 verifies whether the first MAC-I is valid using information conveyed via the security mode command message, the first integrity key, the integrity algorithm, and / or additional parameter(s) (e.g., COUNT, BEARER, and / or DIRECTION as shown in Fig. 4A).

[0063] Generally, the additional parameter(s) used by the UE 102 are the same as the additional parameter(s) used by the BS 104. If the UE 102 verifies that the first MAC-I is valid, the UE 102 activates 310 security protection (e.g., integrity protection and check and / or encryption and decryption) for communicating data (e.g., CP data and / or UP data) with the BS 104, the UE 102 then applies the security protection to the security mode complete message and transmits 312 the security-protected security mode complete message to the BS 104 as described above or below. Otherwise, if the UE 102 verifies that the first MAC-I is invalid, the UE 102 skips event 310 and transmits a security mode failure message to the BS 104. That is, the UE 102 transmits the security mode failure message to the BS 104 without applying security protection to the security mode failure message. In some implementations, the UE 102 generates a null MAC-I (e.g., a MAC-I only includes “0”) and transmits a UL PDU, including the securityPatent Application Attorney Docket Number 0683-124-WOmode failure message and the null MAC-1, to the BS 104. Thus, the BS 104 correctly retrieves the security mode failure message from the UL PDU. If the UE 102 does not include the null MAC-I in the UL PDU and the BS 104 determines the UL PDU includes a MAC-I, the BS 104 determines a wrong end octet for the security mode failure message in the UL PDU. As a result, the BS 104 is not able to retrieve the security mode failure message from the UL PDU.

[0064] In some implementations, the security mode command message configures an encryption algorithm (i.e. , a first encryption algorithm) for encryption and decryption. In some implementations, the UE 102 obtains a first encryption key for encryption and decryption in response to the security mode command message. In some implementations, if the UE 102 verifies the first MAC-I is valid, the UE 102 obtains the first encryption key. Otherwise, the UE 102 refrains from obtaining the first encryption key. In some implementations, the UE 102 obtains (i.e., derives) the first encryption key based on a second base key, an ID of the encryption algorithm, a key derivation function, and / or one or more additional parameters. In some implementations, the UE 102 obtains the one or more additional parameters from a USIM. In other implementations, the UE 102 receives a DL NAS message configuring, indicating, or including the one or more additional parameters from a CN node (e.g., an AMF) via a BS (e.g., the BS 104 or 106). In yet other implementations, the UE 102 derives the one or more additional parameters based on at least one parameter in a DL NAS message received from the CN node via the BS. In yet other implementations, the UE 102 derives the one or more additional parameters based on at least one parameter obtained from the USIM. In yet other implementations, the UE 102 receives the one or more additional parameters from the BS 104. In some implementations, the second base key is a second key for the BS 104 (KBS). In some implementations, the second KBS is a KgNB or a KegNB. In one implementation, the second base key is the same as the first base key. Alternatively, the second base key is different from the first base key. In some implementations, the UE 102 derives the second base key from a second key for CN (KCN). In one implementation, the second key for CN is the same as the first key for CN. Alternatively, the second key for CN is different from the first key for CN. In somePatent Application Attorney Docket Number 0683-124-WOimplementations, the second KCN is a KAMF or a KegAMF. In some implementations, the one or more additional parameters are the same as the one or more additional parameters used for deriving the first integrity key.

[0065] In some implementations, the BS 104 obtains a first encryption key (i.e. , same as the first encryption key obtained by the UE 102) after or in response to event 306 or 308. In some implementations, the BS 104 derives the first encryption key (i.e., same as the first encryption key derived by the UE 102) based on a second base key (i.e., same as the second base key used by the UE 102 to derive the first encryption key of the UE 102), the ID of the encryption algorithm, and / or one or more additional parameters (i.e., same as the one or more additional parameters used by the UE 102 to derive the first encryption key of the UE 102). In some implementations, the BS 104 receives the second base key from the CN node. The CN node generates the second base key from the second KCN. In some implementations, the BS 104 receives the one or more additional parameters in a CN-to-BS message from the CN node. In other implementations, the BS 104 generates the one or more additional parameters. In some implementations, the one or more additional parameters are the same as the one or more additional parameters used for deriving the first integrity key. In some implementations, the one or more additional parameters include security capabilities of the UE 102, indicating support of one or more encryption algorithms. The one or more encryption algorithms include the first encryption algorithm and / or the second encryption algorithm described above or below.

[0066] To transmit the security mode complete message, the UE 102 applies security protection (e.g., integrity protection and / or encryption) to the security mode complete message to generate a respective security-protected security mode complete message. The UE 102 generates the first UL PDU including the security-protected security mode complete message and transmits 312 the first UL PDU to the BS 104. The first UL PDU may be a PDCP PDU. The BS 104 retrieves the security-protected security mode complete message from the first UL PDU and verifies whether the security-protected security mode complete message is valid.Patent Application Attorney Docket Number 0683-124-WO

[0067] When or after activating 310 integrity protection, the UE 102 generates a second MAC-I to protect integrity of the security mode complete message. The UE 102 may generate the second MAC-I using a first integrity key, the integrity algorithm, and / or additional parameter(s), as described for Fig. 4A. For example, the additional parameter(s) include(s) COUNT, BEARER, and / or DIRECTION. As an example, the COUNT may be associated with the security mode complete message. For example, the COUNT consists of a HFN and a PDCP sequence number. The UE 102 assigns the PDCP sequence number for the security mode complete message and includes the PDCP sequence number in the first UL PDU. The BEARER may be a bearer identity (i.e., a value) identifying a bearer used by the UE 102 to transmit the security mode complete message. For example, the bearer is a SRB1 and the BEARER is 1. The DIRECTION may be associated with uplink. For example, the DIRECTION (e.g., a bit) is set to 0 for uplink. In some implementations, when encryption is not enabled (e.g., null encryption is enabled by the security mode command message), the security-protected security mode complete message includes the security mode complete message and the second MAC-I. When the BS 104 receives the first UL PDU, the BS 104 retrieves the security mode complete message and the second MAC-I from the first UL PDU and verifies the second MAC-I. The BS 104 may verify whether the second MAC-I is valid using the first integrity key (e.g., same as the first integrity key used by the UE 102), the integrity algorithm, and / or additional parameter(s) (e.g., same as the first integrity key used by the UE 102) as described for Fig. 4A. In other implementations, when encryption is enabled, e.g., by the security mode command message as described above, the UE 102 encrypts the security mode complete message and the second MAC-I to obtain an encrypted security mode complete message and an encrypted MAC-I respectively. The UE 102 may encrypt the security mode complete message and the second MAC-I using the first encryption key, the encryption algorithm, and / or additional parameter(s) as described for Fig. 4A. For example, the additional parameter(s) include(s) COUNT, BEARER, and / or DIRECTION as described above. In such implementations, the security-protected security mode complete message includes the encrypted security mode complete message and the encrypted MAC-I. When receiving 312 the first UL PDU, the BS 104 retrieves thePatent Application Attorney Docket Number 0683-124-WOencrypted security mode complete message and the encrypted MAC-1 from the first UL PDU. The BS 104 decrypts the encrypted security mode complete message and the encrypted MAC-I to obtain a (decrypted) security mode complete message and a (decrypted) MAC-I. The BS 104 may decrypt the encrypted security mode complete message and the encrypted MAC-I using the first encryption key, the encryption algorithm, and / or additional parameter(s) as described for Fig. 4A. For example, the additional parameter(s) include(s) COUNT, BEARER, and / or DIRECTION and are the same as the additional parameter(s) used by the UE 102. The BS 104 then verifies whether the (decrypted) MAC-I is valid as described for verifying the second MAC-I. To simplify the following description, the second MAC-I is used to represent the (decrypted) MAC-I.

[0068] If or after verifying the second MAC-I is valid, the BS 104 transmits 394 security-protected DL data packets to the UE 102. In some implementations, when integrity protection is activated as described above, the BS 104 generates a respective MAC-I for protecting integrity of each of the DL data packets using the first integrity key, the integrity algorithm, and / or additional parameter(s), similar to the security mode command message. In such implementations, each of the security-protected DL data packets includes a respective integrity-protected DL data packet (i.e. , a DL data packet and a respective MAC-I). In such cases, the UE 102 receives each of the integrity-protected DL data packets and verifies the respective MAC-I as described for the security mode command message. In other implementations, when encryption is activated as described above, the BS 104 encrypts each of the DL data packets to generate a respective encrypted DL data packet, using the first encryption key, the encryption algorithm, and / or additional parameter(s), similar to encrypting the second mode complete message as described for the UE 102. For example, the additional parameter(s) include(s) COUNT, BEARER, and / or DIRECTION. The BS 104 uses (e.g., determines, generates or assigns) a COUNT for each of the DL data packets. The BS 104 sets a BEARER to a bearer identity (i.e., a value) identifying a bearer used by the BS 104 to transmit a respective DL data packet. The BS 104 may set the DIRECTION to a value (e.g., 1 ) for DL. In such cases, each of the security-protected DL data packetsPatent Application Attorney Docket Number 0683-124-WOincludes a respective encrypted DL data packet. When the UE 102 receives each of the encrypted DL data packets, the UE 102 decrypts each encrypted DL data packet using the first encryption key, the encryption algorithm, and / or additional parameter(s), similar to decrypting the security mode complete message as described for the BS 104. For example, the additional parameter(s) include(s) COUNT, BEARER, and / or DIRECTION are the same as the additional parameter(s) used by the BS 104. In yet other implementations, when both integrity protection and encryption are enabled, the BS 104 generates a MAC-I for protecting integrity of each of the DL data packets as described for the security mode command message. The BS 104 then encrypts each DL data packet along with the respective MAC-I to generate an encrypted DL packet and an encrypted MAC-I, using the first encryption key, the encryption algorithm, and / or additional parameter(s), similar to encrypting the security mode complete message as described for the UE 102. For example, the additional parameter(s) include(s) COUNT, BEARER, and / or DIRECTION as described above. In such cases, each of the security-protected DL data packets includes a respective encrypted DL data packet and a respective encrypted DL MAC-I. The UE 102 decrypts each DL data packet and the respective MAC-I, using the first encryption key, the encryption algorithm, and / or additional parameter(s), similar to decrypting the security mode complete message as described for the BS 104. Generally, the additional parameter(s) used by the UE 102 are the same as the additional parameter(s) used by the BS 104.

[0069] In some implementations, the BS 104 includes each of the security-protected DL data packets in a respective PDCP PDU and transmits the 394 the PDCP PDU to the UE 102. The UE 102 retrieves each security-protected DL data packet from the respective PDCP PDU.

[0070] After transmitting 312 the security mode complete message, the UE 102 transmits 394 security-protected UL data packets to the BS 104. In some implementations, when integrity protection is activated as described above, the UE 102 generates a respective MAC-I for protecting integrity of each of the UL data packets as described for the security mode complete message using the first integrity key, the integrity algorithm, and / or additional parameter(s), similar to the security mode completePatent Application Attorney Docket Number 0683-124-WOmessage. In such implementations, each security-protected UL data packet includes a respective integrity-protected UL data packet (i.e. , a respective UL data packet and a respective MAC-1). In such cases, the BS 104 receives and applies integrity check on each of the integrity-protected UL data packets and verifies a respective MAC-I as described for the security mode complete message. In other implementations, when encryption is activated as described above, the UE 102 encrypts each of the UL data packets to generate a respective encrypted UL data packet, using the first encryption key, the encryption algorithm, and / or additional parameter(s), similar to encrypting the second mode complete message. For example, the additional parameter(s) include(s) COUNT, BEARER, and / or DIRECTION. The UE 102 uses (e.g., determines, generates or assigns) a COUNT for each of the UL data packets. The UE 102 sets a BEARER to a bearer identity (i.e., a value) identifying a bearer used by the UE 102 to transmit a respective UL data packet. The UE 102 may set the DIRECTION to a value (e.g., 0) for UL. In such cases, each of the security-protected UL packets includes a respective encrypted UL data packet. When the BS 104 receives each of the encrypted UL data packets, the BS 104 decrypts each encrypted UL data packet using the first encryption key, the encryption algorithm, and / or additional parameter(s), similar to decrypting the security mode complete message. For example, the additional parameter(s) include(s) COUNT, BEARER, and / or DIRECTION. Generally, the additional parameter(s) used by the BS 104 are the same as the additional parameter(s) used by the UE 102.

[0071] In yet other implementations, when both integrity protection and encryption are enabled, the UE 102 generates a MAC-I for protecting integrity of each of the UL data packets using the first integrity key, the integrity algorithm, and / or additional parameter(s) as described for the security mode command message or above. The UE 102 then encrypts each UL data packet along with the respective MAC-I to generate an encrypted UL packet and an encrypted MAC-I, using the first encryption key, the encryption algorithm, and / or additional parameter(s), similar to encrypting the security mode complete message. For example, the additional parameter(s) include(s) COUNT, BEARER, and / or DIRECTION as described above. In such cases, each of the security-protected UL packets includes a respective encrypted UL data packet and a respectivePatent Application Attorney Docket Number 0683-124-WOencrypted MAC-1. The BS 104 decrypts each UL data packet and each respective MAC-I, using the first encryption key, the encryption algorithm, and / or additional parameter(s), similar to decrypting the security mode complete message. Generally, the additional parameter(s) used by the BS 104 are the same as the additional parameter(s) used by the UE 102.

[0072] In some implementations, the UE 102 includes each of the security-protected UL data packets in a respective PDCP PDU and transmits 394 the PDCP PDU to the BS 104. The BS 104 retrieves each security-protected UL data packet from the respective PDCP PDU.

[0073] In some implementations, the DL data packets include at least one DL message (e.g., RRC message(s) or CP message(s)). In some implementations, the at least one DL message includes a UE capability enquiry message, at least one reconfiguration message (e.g., RRCReconfiguration message(s)), and / or at least one DL information transfer message. In some implementations, the UL data packets include at least one UL message (e.g., RRC message(s) or CP message(s)). In some implementations, the at least one UL message includes a UE capability information message, at least one reconfiguration complete message (e.g., RRCReconfigurationComplete message), at least one UL information transfer message, and / or at least one measurement report message. Each of the at least one reconfiguration complete message responds to a respective one of the at least one reconfiguration message. In some implementations, one of the at least one reconfiguration message configures one or more radio bearer(s). The radio bearer(s) may include an SRB (e.g., SRB2) and / or a data radio bearer (DRB). In some implementations, one or some of the at least one reconfiguration message includes one or more measurement configurations. When the UE 102 and BS 104 communicate DL data packets and / or UL data packets via the SRB2, the UE 102 and the BS 104 use the BEARER set to 2 in the security protection as described above. When the UE 102 and BS 104 communicate DL data packets and / or UL data packets via the DRB, the UE 102 and the BS 104 use the BEARER set to a DRB identity (i.e. , a value) in the security protection and operation as described above. The DRB identity identifies the DRB.Patent Application Attorney Docket Number 0683-124-WO

[0074] Generally, if the BS 104 verifies that a MAC-I (e.g., the second MAC-I) received from the UE 102 is invalid, the BS 104 may transmit a release message to the UE 102 to release the connection between the UE 102 and the BS 104. In some implementations, the BS 104 applies security protection to the release message to generate a security-protected release message and transmits the release message to the UE 102, as described for the security mode command message. In other implementations, the BS 104 transmits the release message to the UE 102 without applying security protection to the release message. In such implementations, the BS 104 may deactivate the security protection for communicating data with the UE 102. In such cases, the BS 104 may generate a null MAC-I (e.g., a MAC-I only includes “0”) and transmit a DL PDU, including the release message and the null MAC-I, to the UE 102. Thus, the UE 102 correctly retrieves the release message from the DL PDU. If the BS 104 does not include the null MAC-I in the DL PDU and the UE 102 determines the DL PDU includes a MAC-I, the UE 102 determines a wrong end octet for the release message in the DL PDU. As a result, the UE 102 is not able to retrieve the release message from the DL PDU. In some implementations, the DL PDU is a PDCP PDU.

[0075] In response to receiving 308 the security mode command message, the UE 102 activates 316A security protection to securely communicate MAC CE(s) with the BS 104. In some implementations, if the UE 102 verifies that the first MAC-I is valid, the UE 102 activates 316A the security protection. In some implementations, a first sublayer (e.g., RRC sublayer 212 or PDCP sublayer 208) of the UE 102 indicates a second sublayer (e.g., MAC sublayer 204) of the UE 102 to activate 316A the security protection. Otherwise, if the UE 102 verifies that the first MAC-I is invalid, the UE 102 skips event 316A. Similarly, after event 390, the BS 104 determines 318 to activate or activates 318 security protection for communicating MAC CE(s) with the UE 102. In some implementations, if the BS 104 verifies that the second MAC-I is valid, the BS 104 activates 318 the security protection. Otherwise, if the BS 104 verifies that the second MAC-I is invalid, the BS 104 skips event 318. In other implementations, the BS 104 activates 318 the security protection before receiving event 312. If the BS 104 verifiesPatent Application Attorney Docket Number 0683-124-WOthat the second MAC-1 is invalid, the BS 104 deactivates the security protection for MAC CE(s).

[0076] When or after security protection for MAC CE(s) is activated as described above, the BS 104 determines to transmit a first DL MAC CE. The first DL MAC CE may be related to beam management or radio resource management. The first DL MAC CE may be used to activate or deactivate radio resources. In some implementations, the radio resources include one or more reference signal resources. In other implementations, the radio resources include a PSCell and / or one or more SCell configured for the UE 102. The first DL MAC CE may be a Layer 1 / Layer 2 triggered mobility (LTM) command (may also be referred to as a lower-layer triggered mobility (LTM) command). The first DL MAC CE may activate or deactivate layer 1 or layer 2 measurement configuration and / or reporting. The first DL MAC CE may activate or deactivate transmission of one or more sounding reference signals (SRSs). The first DL MAC CE may be a discontinuous reception (DRX) command or a long DRX command. The first DL MAC CE may activate, deactivate, or indicate one or more Transmission Configuration Indication (TCI) states. The first DL MAC CE may activate or deactivate reception of one or more reference signals (RSs). The first DL MAC CE may update a pathloss RS. The first DL MAC CE may activate, indicate, or deactivate spatial relation for a resource set or a physical channel. The first DL MAC CE may indicate a recommended bit rate. The first DL MAC CE may include a UE ID or a UE Contention Resolution ID. The UE ID may be a radio network temporary identifier (RNTI) such as a cell RNTI, an inactive RNTI, or a RNTI unique in a RAN notification area. The first DL MAC CE may activate or deactivate a measurement gap. The first DL MAC CE may configure or update a UL transmission timing or a DL reception timing. The first DL MAC CE may be a timing advance command. The first DL MAC CE may include a parameter (e.g., Next Hop Chaining Counter parameter) for deriving one or more security keys.

[0077] In some implementations, the BS 104 applies security protection to the first DL MAC CE to generate a security-protected DL MAC CE. The BS 104 then transmits 320 a first DL MAC PDU including the security-protected DL MAC CE and a first DL MAC CE subheader for the first DL MAC CE to the UE 102. When receiving 320Patent Application Attorney Docket Number 0683-124-WOthe first DL MAC PDU, the UE 102 retrieves the first DL MAC CE subheader and the security-protected DL MAC CE from the first DL MAC PDU. Because the UE 102 has activated 316A the security protection, the UE 102 performs security operation to process the security-protected DL MAC CE to obtain a particular DL MAC CE (i.e. , the first DL MAC CE in normal cases). In some implementations, the BS 104 may apply security protection to the first DL MAC CE and the first DL MAC CE subheader to generate a security-protected DL MAC CE. In such cases, the UE 102 performs security operation to process the first DL MAC CE subheader and the security-protected DL MAC CE to obtain a particular DL MAC CE (i.e., the first DL MAC CE). In other implementations, the BS 104 may apply security protection to only the first DL MAC CE to generate a security-protected DL MAC CE. That is, the security protection may not be applied to the first DL MAC CE subheader. In such cases, the UE 102 performs security operation to process only the security-protected DL MAC CE to obtain a particular DL MAC CE (i.e., the first DL MAC CE).

[0078] When or after security protection for MAC CE(s) is activated as described above, the UE 102 determines to transmit a first UL MAC CE. In some implementations, the first UL MAC CE is related to beam management. The first UL MAC CE may be a beam report. The first UL MAC CE may be used for beam failure recovery. The first UL MAC CE may be related to radio resource management. The first UL MAC CE may be used to request radio resources. The first UL MAC CE may be a buffer status report or a delay status report. The first UL MAC CE may be a layer 1 or layer 2 measurement report. The first UL MAC CE may be a power headroom report. The first UL MAC CE may be a measurement gap request or a configured grant confirmation. The first UL MAC CE may include a UE ID. The UE ID may be a radio network temporary identifier (RNTI) such as a cell RNTI, an inactive RNTI, or a RNTI unique in a RAN notification area. The first UL MAC CE may be a timing advance report. The first UL MAC CE may be a recommended bit rate query MAC CE. The first UL MAC CE may include or be a layer 1 or layer 2 measurement report. The first UL MAC CE may be a measurement gap request MAC CE. The first UL MAC CE may be a power headroom report.Patent Application Attorney Docket Number 0683-124-WO

[0079] In some implementations, the DL MAC CEs described above and / or below are MAC CEs for DL shared channel (DL-SCH) or unicast, as specified in 3GPP TS 38.321 or 3GPP 6G MAC specification. In some implementations, the UL MAC CEs described above and / or below are MAC CEs for UL shared channel (UL-SCH) or unicast, as specified in 3GPP TS 38.321 or 3GPP 6G MAC specification.

[0080] In some implementations, the UE 102 applies security protection to the first UL MAC CE to generate a security-protected UL MAC CE. The UE 102 then transmits 322 a first UL MAC PDU including the security-protected UL MAC CE and a first UL MAC CE subheader for the first UL MAC CE to the BS 104. When receiving 322 the first UL MAC PDU, the BS 104 retrieves the first UL MAC CE subheader and the security-protected UL MAC CE from the first UL MAC PDU. Because the BS 104 has activated 318A the security protection, the BS 104 performs a security operation to process the security-protected UL MAC CE to obtain a particular (plain-text) UL MAC CE (i.e. , the first UL MAC CE as described above). In some implementations, the UE 102 may apply security protection to the first UL MAC CE and the first UL MAC CE subheader to generate a security-protected UL MAC CE. In such cases, the BS 104 performs security operation to process the first UL MAC CE subheader and the security-protected UL MAC CE to obtain a particular UL MAC CE (i.e., the first UL MAC CE). In other implementations, the UE 102 may apply security protection to only the first UL MAC CE to generate a security-protected UL MAC CE. That is, the security protection may not be applied to the first UL MAC CE subheader. In such cases, the BS 104 performs security operation to process only the security-protected UL MAC CE to obtain a particular UL MAC CE (i.e., the first UL MAC CE).

[0081] The BS 104 may perform an operation in response to or based on the first UL MAC CE. Here are some implementations of the operation: 1) if the first UL MAC CE requests radio resources, the BS 104 configures radio resources for the UE 102; 2) if the first UL MAC CE is a buffer status report or a delay status report, the BS 104 transmits one or UL grants to the UE 102 based on the buffer status report or the delay status report; 3) if the first UL MAC CE is a layer 1 or layer 2 measurement report, the BS 104 may schedule, reconfigure, or assign radio resources for the UE 102 based onPatent Application Attorney Docket Number 0683-124-WOthe layer 1 or layer 2 measurement report; 4) if the first UL MAC CE is a layer 1 or layer 2 measurement report, the BS 104 may transmit a LTM cell switch command to the UE 102, based on the layer 1 or layer 2 measurement report; 5) if the first UL MAC CE is a beam report, the BS 104 may transmit a DCI or a DL MAC CE to activate, deactivate or indicate one or more TCI states indicated in the beam report; 6) if the first UL MAC CE is beam failure recovery MAC CE, the BS 104 may switch to a beam indicated in the beam failure recovery MAC CE to communicate with the UE 102. Alternatively or additionally, the BS 104 transmits a DCI or a DL MAC CE to the UE 102, indicating a TCI state indicated in the beam failure recovery MAC CE.

[0082] In some implementations, the security protection includes integrity protection and the security operation includes integrity check. In other implementations, the security protection includes encryption and the security operation includes decryption. In yet other implementations, the security protection includes integrity protection and encryption, and the security operation includes integrity check and decryption.

[0083] When the security protection includes integrity protection, the BS 104 generates a third MAC-I for protecting integrity of the first DL MAC CE. In such implementations, the security-protected (i.e. , integrity-protected) DL MAC CE includes the first DL MAC CE and the third MAC-I. In some implementations, the BS 104 generates the third MAC-I using a second integrity key, a second integrity algorithm, and / or additional parameter(s) as described for Fig. 4B. In some implementations, the additional parameter(s) include a UE ID of the UE 102, a first higher layer parameter, DIRECTION, and / or a first logical channel identity as described for Fig. 4B. The DIRECTION may be associated with downlink. For example, the DIRECTION (e.g., a bit) is set to 1 for downlink. In some implementations, the UE ID is a RNTI (e.g., a cell RNTI). In some implementations, the BS 104 transmits a first message to the UE 102 and the first message may include the first higher layer parameter and / or the second integrity algorithm. In some implementations, the first message is the security mode command message. In other implementations, the first message is a message (e.g., an RRC reconfiguration message) other than the security mode command message. InPatent Application Attorney Docket Number 0683-124-WOsuch implementations, the BS 104 may apply security protection to the first message and the UE 102 performs security operation (e.g., decryption and / or integrity check) for the first message, as described above for communicating the DL data packet. In some implementations, the first logical channel identity identifies the first DL MAC CE. The BS 104 includes the first logical channel identity in the first DL MAC CE subheader to identify the first DL MAC CE and includes the first DL MAC CE subheader, the first DL MAC CE, and the third MAC-I in the first DL MAC PDU. When receiving 320 the first DL MAC PDU, the UE 102 retrieves the first DL MAC CE subheader, the first DL MAC CE, and the third MAC-I from the first DL MAC PDU. The UE 102 verifies whether the first DL MAC CE is valid based on the third MAC-I. In some implementations, the UE 102 verifies whether the third MAC-I is valid using the first DL MAC CE or a portion of the first DL MAC CE, a second integrity key (same as the second integrity key used by the BS 104), the second integrity algorithm, the first DL MAC CE subheader (e.g., the first logical channel identity), and / or additional parameter(s) as described above or for Fig.4B. Generally, the additional parameter(s) used by the UE 102 are the same as the additional parameter(s) used by the BS 104. If the UE 102 verifies that the third MAC-I is valid, the UE 102 performs an operation in accordance with the first DL MAC CE. For example, the operation includes the activation or deactivation in the examples of the first DL MAC CE as described above. Otherwise, if the UE 102 verifies that the third MAC-I is invalid, the UE 102 may ignore or discard the first DL MAC CE or the first DL MAC PDU. Alternatively or additionally, if the UE 102 verifies that the third MAC-I is invalid, the UE 102 may determine a failure (e.g., integrity check failure) occurs and / or perform a failure recovery procedure with a BS (e.g., the BS 104 or 106) to recover the failure. The failure recovery procedure may be a connection reestablishment procedure (e.g., a RRC connection reestablishment procedure). In some implementations, the UE 102 may determine the failure occurs and / or perform the failure recovery procedure, only when the UE 102 receives N consecutive invalid MAC-ls for N respective DL MAC CEs. N is an integer and may be one or larger than one. In some implementations, N is predetermined or specified in a 3GPP specification (e.g., TS 38.321 or 6G MAC specification). In other implementations, the UE 102 receives a second message configuring N from the BS 104. The second message may be the security modePatent Application Attorney Docket Number 0683-124-WOcommand message, the first message, or an RRC reconfiguration message. In some implementations, the BS 104 applies security protection to the second message and the UE 102 performs security operation (e.g., decryption and / or integrity check) for the second message, as described for the DL data packet.

[0084] When the security protection includes integrity protection, the UE 102 generates a fourth MAC-I for protecting integrity of the first UL MAC CE. In such implementations, the security-protected UL MAC CE includes the first UL MAC CE and the fourth MAC-I. In some implementations, the UE 102 generates the fourth MAC-I using the second integrity key, the second integrity algorithm, and / or additional parameter(s) as described for Fig. 4B. In some implementations, the additional parameter(s) include a UE ID of the UE 102, a second higher layer parameter, DIRECTION, and / or a second logical channel identity as described for Fig. 4B. The DIRECTION may be associated with uplink. For example, the DIRECTION (e.g., a bit) is set to 0 for uplink. In some implementations, the UE ID is a RNTI (e.g., a cell RNTI). The first message may include the second higher layer parameter. In one implementation, the second higher layer parameter is different from the first higher layer parameter. The first message may include the second higher layer parameter. In another implementation, the second higher layer parameter is the first higher layer parameter. In some implementations, the second logical channel identity identifies the first UL MAC CE. The UE 102 includes the second logical channel identity in the first UL MAC CE subheader to identify the first UL MAC CE and includes the first UL MAC CE subheader, the first UL MAC CE, and the fourth MAC-I in the first UL MAC PDU. When receiving 322 the first UL MAC PDU, the BS 104 retrieves the first UL MAC CE subheader, the first UL MAC CE, and the fourth MAC-I from the first UL MAC PDU. The BS 104 verifies whether the first UL MAC CE is valid based on the fourth MAC-I. In some implementations, the BS 104 verifies whether the fourth MAC-I is valid using the first UL MAC CE or a portion of the first UL MAC CE, the second integrity key (same as the second security key used by the UE 102), the second integrity algorithm, the first UL MAC CE subheader (e.g., the second logical channel identity), and / or additional parameter(s) as described above or for Fig. 4B. Generally, the additional parameter(s)Patent Application Attorney Docket Number 0683-124-WOused by the BS 104 are the same as the additional parameter(s) used by the UE 102. If the BS 104 verifies that the fourth MAC-I is valid, the BS 104 performs an operation in accordance with the first UL MAC CE. Otherwise, if the BS 104 verifies that the fourth MAC-I is invalid, the BS 104 may ignore or discard the first UL MAC CE or the first UL MAC PDU. Alternatively or additionally, if the BS 104 verifies that the fourth MAC-I is invalid, the BS 104 may determine a failure (e.g., integrity check failure) occurs and / or transition the UE 102 to an idle state. In some implementations, the BS 104 may determine the failure occurs and / or transitions the UE 102 to the idle state, only when the BS 104 receives M consecutive invalid MAC-ls for M respective UL MAC CEs. Here, M is an integer and may be one or larger than one. In some implementations, M is predetermined or preconfigured by the BS 104.

[0085] In some implementations, the second integrity algorithm is different from the first integrity algorithm. In other implementations, the second integrity algorithm is the same as the first integrity algorithm. The second integrity algorithm may be a 64-bit algorithm or a 128-bit algorithm. The first integrity algorithm may be a 128-bit algorithm, 256-bit algorithm, or a 512-bit algorithm.

[0086] In some implementations, the first integrity key and the second integrity key are the same. In other implementations, the first integrity key and the second integrity key are different. The first integrity key may be a 128-bit key, a 256-bit key, or a 512-bit key. The second integrity key may be a 64-bit key or a 128-bit key. In some implementations, the BS 104 derives the second integrity key from the first integrity key. For example, the BS 104 derives the second integrity key using the first integrity key, an ID of the second integrity algorithm, and / or one or more parameters. In such implementations, the UE 102 derives the second integrity key from the first integrity key. For example, the UE 102 derives the second integrity key using the first integrity key, the ID of the second integrity algorithm, and / or the one or more parameters. In other implementations, the BS 104 derives the second integrity key from the first base key. For example, the BS 104 derives the second integrity key using the first base key, the ID of the second integrity algorithm, and / or one or more parameters. In such implementations, the UE 102 derives the second integrity key using the first base key,Patent Application Attorney Docket Number 0683-124-WOthe ID of the second integrity algorithm, and / or the one or more parameters. The first message may include the ID of the second integrity algorithm and / or the one or more parameters. In alternative implementations, the UE 102 receives the second integrity key from the BS 104. For example, the first message includes the second integrity key. In some implementations, the one or more parameters include a UE ID of the UE 102. For example, the UE ID is a RNTI (e.g., cell RNTI). In other implementations, the one or more parameters include a number or a counter.

[0087] When the security protection includes encryption, the BS 104 encrypts the first DL MAC CE to obtain an encrypted DL MAC CE. In such implementations, the security-protected DL MAC CE includes the encrypted DL MAC CE. In some implementations, the BS 104 encrypts the first DL MAC CE using a second encryption key, a second encryption algorithm, and / or additional parameter(s) as described for Fig.4B. In some implementations, the additional parameter(s) includes a UE ID of the UE 102, a third higher layer parameter, DIRECTION, and / or the first logical channel identity as described for Fig. 4B. The DIRECTION may be associated with downlink. For example, the DIRECTION (e.g., a bit) is set to 1 fordownlink. In some implementations, the UE ID is a RNTI (e.g., a cell RNTI). The first message may include the third higher layer parameter. Alternatively, the third higher layer parameter is the first higher layer parameter. The BS 104 includes the first DL MAC CE subheader and the encrypted DL MAC CE in the first DL MAC PDU. When receiving 320 the first DL MAC PDU, the UE 102 retrieves the first DL MAC CE subheader and the encrypted DL MAC CE from the first DL MAC PDU. The UE 102 decrypts the encrypted DL MAC CE to obtain a first (decrypted) DL MAC CE, using a second encryption key (same as the second encryption key used by the BS 104), the second encryption algorithm, the first DL MAC CE subheader, and / or additional parameter(s) as described above. Generally, the additional parameter(s) used by the UE 102 are the same as the additional parameter(s) used by the BS 104. The UE 102 applies the first (decrypted) DL MAC CE.

[0088] In some implementations, upon receiving the first DL MAC CE, the UE 102 performs an operation in accordance with the first (decrypted) DL MAC CE.Depending on the first DL MAC CE as described in the examples of the first DL MACPatent Application Attorney Docket Number 0683-124-WOCE, the operation may include 1) activating or deactivating the radio resources, TCI state(s), transmission of the SRS(s), reception of the RS(s), the layer 1 or layer 2 measurement configuration and / or reporting, or a measurement gap; 2) updating the pathloss RS or UL transmission timing; 3) entering or applying the DRX; 4) activating, applying or deactivating the spatial relation for a resource set or physical channel; 5) applying the recommended bit rate; or 6) applying the UE ID in communication with the BS 104.

[0089] When the security protection includes encryption and integrity protection, the BS 104 generates the third MAC-I as described above. In some implementations, the BS 104 encrypts the integrity-protected DL MAC CE to obtain an encrypted, integrity-protected DL MAC CE, e.g., using the second encryption key, the second encryption algorithm, and / or the additional parameter(s). In such implementations, the security-protected DL MAC CE includes the encrypted, integrity-protected DL MAC CE. The BS 104 includes the first DL MAC CE subheader and the encrypted, integrity-protected DL MAC CE in the first DL MAC PDU. When receiving 320 the first DL MAC PDU, the UE 102 retrieves the first DL MAC CE subheader and the encrypted, integrity-protected DL MAC CE from the first DL MAC PDU. The UE 102 decrypts the encrypted, integrity-protected DL MAC CE to obtain a first (decrypted) integrity-protected DL MAC CE, using a second encryption key (same as the second encryption key used by the BS 104), the second encryption algorithm, the first DL MAC CE subheader (e.g., the first logical channel identity), and / or additional parameter(s) as described above. Generally, the additional parameter(s) used by the UE 102 are the same as the additional parameter(s) used by the BS 104. The UE 102 verifies the third MAC-I as described above. Based on a verification result of the third MAC-I, the UE 102 may perform actions as described above.

[0090] Alternatively, when the security protection includes encryption and integrity protection, the BS 104 obtains the encrypted DL MAC CE as described above and then generates a fifth MAC-I for the encrypted DL MAC CE as described for the third MAC-I. In such cases, the BS 104 includes the encrypted DL MAC CE and the fifth MAC-I in the first DL MAC PDU. The UE 102 verifies the fifth MAC-I as described for thePatent Application Attorney Docket Number 0683-124-WOthird MAC-1. If the UE 102 verifies the fifth MAC-I is valid, the UE 102 decrypts the encrypted DL MAC CE as described above. Otherwise, if the UE 102 verifies the fifth MAC-I is invalid, the UE 102 may ignore or discard the encrypted DL MAC CE or the first DL MAC PDU. Alternatively or additionally, if the UE 102 verifies the fifth MAC-I is invalid, the UE 102 may determine that a failure (e.g., integrity check failure) occurs and / or perform a failure recovery procedure (e.g., an RRC connection reestablishment procedure) to recover the failure as described above.

[0091] When the security protection includes encryption, the UE 102 encrypts the first UL MAC CE to obtain an encrypted UL MAC CE. In such implementations, the security-protected UL MAC CE includes the encrypted UL MAC CE. In some implementations, the UE 102 encrypts the first UL MAC CE using a second encryption key, a second encryption algorithm, and / or additional parameter(s). In some implementations, the additional parameter(s) include a UE ID of the UE 102, a fourth higher layer parameter, DIRECTION, and / or the second logical channel identity as described for Fig. 4B. In some implementations, the UE ID is a RNTI (e.g., a cell RNTI). The DIRECTION may be associated with uplink. For example, the DIRECTION (e.g., a bit) is set to 0 for uplink. The first message may include the fourth higher layer parameter. Alternatively, the fourth higher layer parameter is the first, second, or third higher layer parameter. The UE 102 includes the first UL MAC CE subheader and the encrypted UL MAC CE in the first UL MAC PDU. When receiving 322 the first UL MAC PDU, the BS 104 retrieves the first UL MAC CE subheader and the encrypted UL MAC CE from the first UL MAC PDU. The BS 104 decrypts the encrypted UL MAC CE to obtain a first (decrypted) UL MAC CE, using the second encryption key (same as the second encryption key used by the UE 102), the second encryption algorithm, the first UL MAC CE subheader (e.g., the second logical channel identity), and / or additional parameter(s) as described above. Generally, the additional parameter(s) used by the UE 102 are the same as the additional parameter(s) used by the BS 104. The BS 104 then performs an operation in accordance with the first (decrypted) UL MAC CE as described above.Patent Application Attorney Docket Number 0683-124-WO

[0092] When the security protection includes encryption and integrity protection, the UE 102 generates the fourth MAC-I to obtain the integrity-protected UL MAC CE as described above. In some implementations, the UE 102 encrypts the integrity-protected UL MAC CE to obtain an encrypted, integrity-protected UL MAC CE, e.g., using the second encryption key, the second encryption algorithm, and / or the additional parameter(s). In such implementations, the security-protected UL MAC CE includes the encrypted, integrity-protected UL MAC CE. The UE 102 includes the first UL MAC CE subheader and the encrypted, integrity-protected UL MAC CE in the first UL MAC PDU. When receiving 322 the first UL MAC PDU, the BS 104 retrieves the first UL MAC CE subheader and the encrypted, integrity-protected UL MAC CE from the first UL MAC PDU. The BS 104 decrypts the encrypted, integrity-protected UL MAC CE to obtain a first (decrypted) integrity-protected UL MAC CE, using a second encryption key (same as the second encryption key used by the BS 104), the second encryption algorithm, the first UL MAC CE subheader (e.g., the second logical channel identity), and / or additional parameter(s) as described above. Generally, the additional parameter(s) used by the UE 102 are the same as the additional parameter(s) used by the BS 104. The BS 104 verifies the fourth MAC-I as described above. Based on a verification result of the fourth MAC-I, the BS 104 may perform actions as described above.

[0093] Alternatively, when the security protection includes encryption and integrity protection, the UE 102 obtains the encrypted UL MAC CE as described above and then generates a sixth MAC-I for the encrypted UL MAC CE as described for the fourth MAC-L In such cases, the UE 102 includes the encrypted UL MAC CE and the sixth MAC-I in the first UL MAC PDU. The BS 104 verifies the sixth MAC-I as described for the fourth MAC-I. Based on a verification result of the sixth MAC-I, the BS 104 perform actions as described for the fourth MAC-I.

[0094] In some implementations, the second encryption algorithm is different from the first encryption algorithm. In other implementations, the second encryption algorithm is the same as the first encryption algorithm. The second encryption algorithm may be a 64-bit algorithm or a 128-bit algorithm. The first encryption algorithm may be a 128-bit algorithm, 256-bit algorithm, or a 512-bit algorithm.Patent Application Attorney Docket Number 0683-124-WO

[0095] In some implementations, the first encryption key and the second encryption key are the same. In other implementations, the first encryption key and the second encryption key are different. The first encryption key may be a 128-bit key, a 256-bit key, or a 512-bit key. The second encryption key may be a 64-bit key or a 128-bit key. In some implementations, the BS 104 derives the second encryption key from the first encryption key. For example, the BS 104 derives the second encryption key using the first encryption key, an ID of the second encryption algorithm, and / or one or more parameters. In such implementations, the UE 102 derives the second encryption key from the first encryption key. For example, the UE 102 derives the second encryption key using the first encryption key, the ID of the second encryption algorithm, and / or the one or more parameters. In other implementations, the BS 104 derives the second encryption key from the first base key. For example, the BS 104 derives the second encryption key using the first base key, the ID of the second encryption algorithm, and / or one or more parameters. In such implementations, the UE 102 derives the second encryption key from the first base key. For example, the UE 102 derives the second encryption key using the first base key, the ID of the second encryption algorithm, and / or the one or more parameters. The first message may include the ID and / or the one or more parameters. In some alternative implementations, the UE 102 receives the second encryption key from the BS 104, e.g., in the first message. In some implementations, the one or more parameters include a UE ID of the UE 102. For example, the UE ID is a RNTI (e.g., cell RNTI). In other implementations, the one or more parameters include a number or a counter.

[0096] In some implementations, the length of each of the MAC-ls for the MAC CEs is smaller than the length of the MAC-ls for data (e.g., the security mode command, security mode complete, and / or data packets). In other implementations, the length of each of the MAC-ls for the MAC CEs is equal to the length of the MAC-ls for data (e.g., the security mode command, security mode complete, and / or data packets). In some implementations, each of the MAC-ls for data is Z bits long. In some implementations, each of the MAC-ls for the MAC CEs is Y bits long (Y < Z). Z and Y are positive integers. For example, Z is smaller than 257. In another example, Z is 32,Patent Application Attorney Docket Number 0683-124-WO64, 128, or 256. For example, Y is smaller than 33. In another example, Y is 8, 10, 12, 14, 16, 18, 20, or 32.

[0097] In some implementations, when or after security protection for MAC CE(s) is activated as described above, the BS 104 may transmit 324 one or more DL MAC PDUs including non-security protected DL MAC CE to the UE 102. In some implementations, the BS 104 may include the DL PDU(s) described for event 394 in the first DL MAC PDU and / or the one or more DL MAC PDUs. In other implementations, the BS 104 may transmit 394 one or more other DL MAC PDUs including the DL PDU(s) to the UE 102.

[0098] In some implementations, when or after security protection for MAC CE(s) is activated as described above, the UE 102 may transmit 326 one or more UL MAC PDUs including non-security protected UL MAC CE to the BS 104. In some implementations, the UE 102 may include the UL PDU(s) described for event 394 in the first UL MAC PDU and / or the one or more UL MAC PDUs. In other implementations, the UE 102 may transmit 394 one or more other UL MAC PDUs including the UL PDU(s) to the BS 104.

[0099] In some implementations, event 394 may occur before or after events 320, 322, 324, or 326. In other implementations, event 394 may occur together with event 320, 322, 324, or 326.

[0100] In some implementations, security protection for some MAC CEs may be required and specified in TS 38.321 or 3GPP 6G MAC specification and security protection for other MAC CEs may not be required as specified in a 3GPP specification (e.g., TS 38.321 or 3GPP 6G MAC specification). Thus, when communicating with a MAC CE with the BS 104, the UE 102 can determine whether to apply security protection or operation to the MAC CE in accordance with the 3GPP specification.Similarly, when communicating with a MAC CE with the UE 102, the BS 104 can determine whether to apply security protection or operation to the MAC CE in accordance with the 3GPP specification.Patent Application Attorney Docket Number 0683-124-WO

[0101] In other implementations, the BS 104 can include a configuration in the first message or a security activation command (as described for Fig. 3B), configuring security protection for some MAC CEs. If the BS 104 does not configure the UE 102 to apply security protection for a particular MAC CE, the BS 104 and the UE 102 determine no security protection is configured for the MAC CE. Thus, when communicating with a MAC CE with the BS 104, the UE 102 can determine whether to apply security protection or operation to the MAC CE in accordance with the configuration. Similarly, when communicating with a MAC CE with the UE 102, the BS 104 can determine whether to apply security protection or operation to the MAC CE in accordance with the configuration.

[0102] Fig. 3B depicts a scenario 300B similar to the scenario 300A. The difference between the scenarios 300B and 300A is that the BS 104 transmits 314 a security activation command to the UE 102, specifically activating security protection for MAC CE(s). The BS 104 determines to activate security protection for MAC CE(s) and transmits 314 the security activation command after event 308, 312, or 394. The BS 104 may activate 318 security protection for MAC CE(s) in response to the determination or event 314. Depending on implementations, the UE 102 may or may not transmit a security activation response to the BS 104 in response to the security activation command.

[0103] In some implementations, the security activation command is an RRC message (e.g., RRC reconfiguration message). In such implementations, the BS 104 may apply security protection (e.g., integrity protection and / or encryption) to the security activation command to obtain a security-protected security activation command, similar to applying security protection to the security mode command message or DL data packet as described for Fig. 3A. The BS 104 transmits 314 the security-protected security activation command to the UE 102. When receiving 314 the security-protected security activation command, the UE 102 performs a security operation for the security-protected security activation command to obtain the security activation command, similar to performing a security operation for the DL data packet as described for Fig.3A.Patent Application Attorney Docket Number 0683-124-WO

[0104] In some implementations, if the UE 102 verifies integrity (e.g., a MAC-I) for the security activation command is invalid, the UE 102 may transmit a security activation failure message to the BS 104. In some implementations, descriptions for the security mode failure message can apply to the security activation failure message. Alternatively, if the UE 102 verifies integrity (e.g., a MAC-I) for the security activation command is invalid, the UE 102 determines a failure and performs a failure recovery procedure with the BS 104 to recover the failure as described above.

[0105] Otherwise, if the UE 102 verifies integrity (e.g., a MAC-I) for the security activation command is valid, the UE 102 activates 316B security protection for MAC CE(s) as described for event 316A. In some implementations, the UE 102 performs security protection for the security activation response to obtain a security-protected security activation response, as described for transmitting the security mode complete message or UL data packet for Fig. 3A. The UE 102 transmits the security-protected security activation response to the BS 104. The BS 104 receives the security-protected security activation response and performs security operation (e.g., decryption and / or integrity check) for the security-protected security activation response to obtain the security activation response, as described for receiving and obtaining the security mode complete or UL data packet for Fig. 3A. If the BS 104 verifies integrity for the security activation response is valid, the BS 104 activates 318 security protection for MAC CE(s) as described for Fig. 3A. Otherwise, if the BS 104 verifies integrity for the security activation response is invalid, the BS 104 may transmit a release message to the UE 102 to release the connection between the UE 102 and the BS 104 as described for Fig.3A.

[0106] In other implementations, the security activation command is a DL MAC CE. In some implementations, the BS 104 applies security protection to the security activation command MAC CE to obtain a security-protected security activation command MAC CE, similar to applying security protection to the first DL MAC CE as described for Fig. 3A. In some implementations, a logical channel identity identifies the security activation command MAC CE. The BS 104 may generate a MAC CE subheader including the logical channel identity and includes the MAC CE subheaderPatent Application Attorney Docket Number 0683-124-WOand the security-protected security activation command MAC CE in a DL MAC PDU. The BS 104 transmits 314 the DL MAC PDU to the UE 102. When receiving 314 the DL MAC PDU, the UE 102 retrieves the MAC CE subheader and the security-protected security activation command MAC CE from the DL MAC PDU and performs a security operation (e.g., decryption and / or integrity check) for the security-protected security activation command MAC CE, similar to retrieving and performing the security operation for the first DL MAC CE as described for Fig. 3A. If the UE 102 obtains a valid security activation command MAC CE (i.e. , the same as the security activation command MAC CE generated by the BS 104) as a result of the security operation, the UE 102 activates 316B security protection for MAC CE(s). Otherwise, if the UE 102 obtains an invalid security activation command MAC CE, the UE 102 may ignore or discard the security activation command MAC CE. Alternatively or additionally, if the UE 102 obtains an invalid security activation command MAC CE, the UE 102 may determine that a failure (integrity check failure) occurs and / or perform a failure recovery procedure to recover the failure as described for Fig. 3A.

[0107] In some implementations, the security activation response may be a UL MAC CE, if transmitted. The UE 102 may perform security protection for the security activation response MAC CE, similar to performing security protection for the first UL MAC CE as described for Fig. 3A. In some implementations, a logical channel identity identifies the security activation response MAC CE. The UE 102 may generate a MAC CE subheader including the logical channel identity and includes the MAC CE subheader and the security-protected security activation response MAC CE in a UL MAC PDU. The UE 102 transmits the UL MAC PDU to the BS 104. When receiving the UL MAC PDU, the BS 104 retrieves the MAC CE subheader and the security-protected security activation response MAC CE from the UL MAC PDU and performs security operation (e.g., decryption and / or integrity check) for the security-protected security activation response MAC CE, similar to retrieving and performing security operation for the first UL MAC CE as described for Fig. 3A. If the BS 104 obtains a valid security activation response MAC CE (i.e., the same as the security activation response MAC CE generated by the UE 102) as a result of the security operation, the BS 104Patent Application Attorney Docket Number 0683-124-WOdetermines that the BS 104 successfully commands the UE 102 to activate security protection for MAC CE(s). Otherwise, if the BS 104 obtains an invalid security activation response MAC CE as a result of the security operation, the BS 104 may determine that the security activation at the UE 102 fails. In one implementation, the BS 104 retransmits the security-protected security activation command MAC CE as described above. In another implementation, the BS 104 performs security protection for the security activation command MAC CE again to obtain a new security-protected security activation command MAC CE as described above. The BS 104 transmits the new security-protected security activation command MAC CE to the UE 102 in another UL MAC PDU as described above. Alternatively, the BS 104 may determine a failure occurs and / or transition the UE 102 to an idle state as described for Fig. 3A. In some implementations, the BS 104 may determine a failure occurs and / or transitions the UE 102 to the idle state, only when the BS 104 fails to command the UE 102 to activate security protection for MAC CE(s) in K consecutive times. K is an integer and may be one or larger than one. In some implementations, K is predetermined or preconfigured by the BS 104.

[0108] In some implementations, the security activation command includes parameter(s) for deriving the second integrity key and / or the second encryption key as described for Fig. 3A. In other alternative implementations, the security activation command does not include parameter(s) for deriving the second integrity key and / or the second encryption key. In some implementations, the UE 102 derives the second integrity key and / or the second encryption key as described for Fig. 3A. Likewise, the BS 104 derives the second integrity key and / or the second encryption key as described for Fig. 3A.

[0109] In some implementations, the security activation command includes parameter(s) for performing security protection (e.g., integrity protection and / or encryption) for MAC CE(s) and / or performing security operation (e.g., integrity check and / or decryption) for MAC CE(s) as described for Fig. 3A. In other alternative implementations, the security activation command does not include parameter(s) for performing security protection (e.g., integrity protection and / or encryption) for MACPatent Application Attorney Docket Number 0683-124-WOCE(s) and / or performing security operation (e.g., integrity check and / or decryption) for MAC CE(s). Instead, the parameter(s) may be included in the security mode command message. In some implementations, the LIE 102 may perform security protection (e.g., integrity protection and / or encryption) for UL MAC CE(s) and / or perform security operation (e.g., integrity check and / or decryption) for received DL MAC CE(s), as described for Fig. 3A. Likewise, the BS 104 may perform security protection (e.g., integrity protection and / or encryption) for DL MAC CE(s) and / or perform security operation (e.g., integrity check and / or decryption) for received UL MAC CE(s), as described for Fig. 3A.

[0110] Fig. 4A illustrates using an integrity algorithm for integrity protection and integrity check of data. The sender 401 and the receiver 411 (which each may be a UE (e.g., the UE 102) or a RAN node, such as, a base station (e.g., the BS 104)) use the same integrity algorithm to generate a Z-bit MAC-I and a Z-bit XMAC-I (here X stands for “expected”), respectively, based on a Ki -bit integrity KEY, an L-bit COUNT, an M-bit BEARER identity, and a 1 -bit DIRECTION of the transmission (which is Ofor uplink and 1 for downlink), and the MESSAGE itself. In some implementations, the MESSAGE is a message, a UL data packet or a DL data packet as described for Fig. 3A or Fig. 3B. In other implementations, the MESSAGE is a UL PDU including a UL message, a UL PDU including a UL data packet, a DL PDU including a DL message, ora DL PDU including a DL data packet as described for Fig. 3A or Fig. 3B. In some implementations, the UL PDUs and DL PDUs are PDCP PDUs. In some implementations, Ki is 128, 256, or 512. In some implementations, L is 32, 64, 128, 256, or 512. In some implementations, M is 5 or 6. In some implementations, the integrity algorithm is a null algorithm known as (e.g., NIA0 or6GIA0), which does not provide integrity protection. In some implementations, the integrity algorithm is a Ki -bit SNOW 3G based algorithm, a Ki -bit AES based algorithm, a Ki -bit ZUC based algorithm, or a Ki-bit SHA based algorithm. The sender 401 appends the MAC-I to the MESSAGE. The receiver 411 verifies integrity by comparing the XMAC-I with the MAC-I appended to the MESSAGE.

[0111] Fig. 4B illustrates using an integrity algorithm for integrity protection and integrity check of MAC CEs. The sender 401 and the receiver 411 (which each may bePatent Application Attorney Docket Number 0683-124-WOa UE (e.g., the UE 102) or a network entity, such as, a base station (e.g., the BS 104)) use the same integrity algorithm to generate a Y-bit MAC-I and XMAC-I (here X stands for “expected”), respectively, based on a K2-bit integrity KEY, an N-bit logical channel identity (LCID), a 1 -bit DIRECTION of the transmission, a UE ID, and / or a higher layer parameter, and the MESSAGE itself. In some implementations, the UE ID is a RNTI (e.g., cell RNTI). In some implementations, the MESSAGE is a MAC CE as described for Fig. 3A or Fig. 3B. In other implementations, the MESSAGE is a MAC subPDU, including a MAC CE subheader and a MAC CE, as described for Fig. 3A or Fig. 3B. In other implementations, the MESSAGE is a plurality of MAC subPDUs, each including a MAC CE subheader and a MAC CE, as described for Fig 3A or Fig. 3B. In some implementations, K2 < Ki. For example, K2 is 32, 64, 128, 256, or 512. In some implementations, N is < 16. For example, N is 5, 6, 7, 8, or 16. In some implementations, the UE ID has P bits. For example, P < 32. In another example, P is 16, 24, or 32. In some implementations, the integrity algorithm is a null algorithm (e.g., NIAO or 6GIA0), which does not provide integrity protection. In some implementations, the integrity algorithm is a K2-bit SNOW 3G based algorithm, a K2-bit AES based algorithm, a K2-bit ZUC based algorithm, or a K2-bit SHA based algorithm. The sender 401 appends the MAC-I to the MESSAGE. The receiver 411 verifies integrity by comparing the XMAC-I with the MAC-I appended to the MESSAGE.

[0112] Fig. 5A illustrates using a ciphering algorithm for encrypting and decrypting data. Both sender 501 and receiver 511 (which each may be a UE (e.g., the UE 102) or a network entity, such as, a base station (e.g., the BS 104)) use a ciphering algorithm to generate an output KEYSTREAM block using a Ks-bit cipher KEY, a L-bit COUNT, a M-bit BEARER identity, the 1 -bit DIRECTION of the transmission, and the LENGTH of the keystream (e.g., a PLAINTEXT block) as input parameters. The sender 501 then uses the KEYSTREAM block to encrypt the PLAINTEXT block thereby generating the output CIPHERTEXT block. In some implementations, the PLAINTEXT is a message, a UL data packet or a DL data packet as described for Fig. 3A or Fig. 3B. In other implementations, the PLAINTEXT includes a message and a MAC-I for the message, a UL data packet and a MAC-I for the UL data packet, or a DL data packetPatent Application Attorney Docket Number 0683-124-WOand a MAC-1 for the DL data packet, as described for Fig. 3A or Fig. 3B. In some implementations, K3 is 128, 256, or 512. L and M are as described for Fig. 4A. The receiver 511 uses the KEYSTREAM block, which it generates in the same manner as the sender, to decrypt the CIPHERTEXT block thereby regenerating the output PLAINTEXT block. The sender 501 and the receiver 511 use the same ciphering algorithm. In some implementation, the ciphering algorithm is a null ciphering algorithm (e.g., NEAO or 6GEA0), which provides no encryption. In some implementations, the ciphering algorithm is a Ks-bit SNOW 3G based algorithm, a Ks-bit AES based algorithm, a 128-bit ZUC based algorithm Ks-bit, or a Ks-bit SHA based algorithm.

[0113] Fig. 5B illustrates using a ciphering algorithm for encrypting and decrypting MAC CEs. Both sender 501 and receiver 511 (which each may be a UE (e.g., the UE 102) or a network entity, such as, a base station (e.g., the BS 104)) use a ciphering algorithm to generate an output KEYSTREAM block using a K4-bit cipher KEY, a N-bit logical channel identity (LCID), the 1 -bit DIRECTION of the transmission, the LENGTH of the keystream (e.g., the PLAINTEXT block), a UE ID, and / or a higher layer parameter as input parameters. In some implementations, the UE ID is a RNTI (e.g., cell RNTI). The sender 501 then uses the KEYSTREAM block to encrypt the PLAINTEXT block thereby generating the output CIPHERTEXT block. In some implementations, the PLAINTEXT is a UL MAC CE or a DL MAC CE as described for Fig. 3A or Fig. 3B. In some implementations, the PLAINTEXT block includes a MAC CE and a MAC-I for the MAC-I as described for Fig. 3A or Fig. 3B. In other implementations, the PLAINTEXT block is a plurality of MAC subPDUs, each including a MAC CE subheader and a MAC CE, as described for Fig 3A or Fig. 3B. In some implementations, K4 is 32, 64, 128, 256, or 512. N and the UE ID are as described for Fig. 4B. The receiver 511 uses the KEYSTREAM block, which it generates in the same manner as the sender, to decrypt the CIPHERTEXT block thereby regenerating the output PLAINTEXT block. The sender 501 and the receiver 511 use the same ciphering algorithm. In some implementation, the ciphering algorithm is a null ciphering algorithm (e.g., NEAO or 6GEA0), which provides no encryption. In some implementations, thePatent Application Attorney Docket Number 0683-124-WOciphering algorithm is a K4-bit SNOW 3G based algorithm, a K -bit AES based algorithm, a 128-bit ZUC based algorithm K4-bit, or a K4-bit SHA based algorithm.

[0114] Fig. 6A exemplarily illustrates MAC PDU 602 having one or more MAC subPDUs with a security protected MAC CE. In MAC PDU 602, each MAC CE is security-protected. The first MAC subPDU 601 A of MAC PDU 602 includes a MAC CE subheader and a security-protected MAC CE. The second MAC subPDU 601 B of MAC PDU 602 includes a MAC CE subheader and a security-protected MAC CE. Other MAC SDU(s) 603 can include security-protected data.

[0115] Fig. 6B exemplarily illustrates MAC PDU 604 having MAC subPDUs including a security-protected MAC CE or a non-security protected MAC CE each. The non-security-protected MAC CEs and security-protected MAC CEs in the MAC PDU 604 may be multiplexed. The first MAC subPDU 605A includes a MAC CE subheader and a non-security-protected MAC CE. The second MAC CE subPDU 605B includes a MAC CE subheader and a security-protected MAC CE. Other MAC SDUs 607 include security-protected data.

[0116] Figs. 6C and 6D show example MAC PDU 606 and example MAC PDU 608, respectively. In one example, a single security protection indication MAC CE is used to indicate one or more MAC CEs are security-protected. The security protection indication MAC CE is in the front of the MAC PDU 606 in Fig. 6C, while the security protection indication MAC CE is at the end of the security-protected MAC CEs in MAC PDU 608 in Fig. 6D.

[0117] As shown in Fig. 6C, the first MAC subPDU 609A includes a MAC CE subheader and a MAC-I. The second MAC subPDU 609B includes a MAC CE subheader and a MAC CE. The third MAC subPDU 609C includes a MAC CE subheader and a MAC CE. Other MAC SDUs 611 can include security-protected data.

[0118] As shown in Fig. 6D, the first MAC subPDU 613A includes a MAC CE subheader and a MAC CE, the second MAC subPDU 613B includes a MAC CE subheader and a MAC CE, and the third MAC subPDU 613C includes a MAC CE subheader and a MAC-I. Other MAC SDUs 615 can include security-protected data.Patent Application Attorney Docket Number 0683-124-WO

[0119] The format of the MAC PDU 602, 604, 606, and / or 608 may be applicable to MAC PDUs described for Figs. 3A and 3B. The descriptions for security-protected MAC CEs described for Figs. 3A and 3B may apply the security-protected MAC CEs in Figs. 6A-6D. The descriptions for security-protected data packets or messages described for Figs. 3A and 3B may apply the security-protected data in Figs. 6A-6D. If there is neither data packet nor message to transmit, the MAC subPDUs including MAC SDUs in the MAC PDU 602, 604, 606, 608 can be omitted. Generally, the MAC PDU 602, 604, 606, 608 can include any number of MAC subPDU, where each MAC subPDU includes a MAC CE subheader and a MAC CE.

[0120] Next, several example methods, which can be implemented in a RAN node (e.g., the BS 104 or 106) ora UE (e.g., the UE 102), are discussed with reference to Figs. 7A-14C. Descriptions and example implementations described for Figs. 3A-6D can apply to Figs. 7A-16.

[0121] Fig. 7A illustrates an example method 700A, which is performed by a UE 102. The method 700A begins at block 792, where the UE 102 performs a security mode procedure with a RAN 105. At block 708, the UE 102 activates security protection for data communication with the RAN 105 in response to the security mode procedure. At block 716A, the UE 102 activates security protection for communicating MAC CE(s) with the RAN 105 in response to the security mode procedure. At block 794, the UE 102 communicates security-protected data with the RAN 105. At block 721 , the UE 102 communicates security-protected MAC CEs with the RAN 105 (e.g., events 320 and / or 322). At block 725, the UE 102 communicates non-security-protected MAC CEs with the RAN 105 (e.g., events 302, 304, 324, and / or 326). Block 725 can occur before, during, or after any block described above.

[0122] Fig. 7B is a flow diagram of an example method 700B similar to the method 700A, except that the method 700B includes blocks 714 and 716B instead of block 716A. At block 714, the UE 102 receives a security activation command from the RAN 105. At block 716B, the UE 102 activates security protection for communicating MAC CE(s) with the RAN 105 in response to the security activation command.Patent Application Attorney Docket Number 0683-124-WO

[0123] Fig. 8A illustrates an example method 800A, which is performed by a BS 104. The method 800A begins at block 892, where the BS 104 performs a security mode procedure with a UE 102. At block 806, the BS 104 activates security protection for data communication with the UE 102 in response to the security mode procedure. At block 818, the BS 104 activates security protection for communicating MAC CE(s) with the UE 102 in response to the security activation procedure. At block 894, the BS 104 communicates security-protected data with the UE 102. At block 821 , the BS 104 communicates security-protected MAC CEs with the UE RAN (e.g., events 320 and / or 322). At block 825, the BS 104 communicates non-security-protected MAC CEs with the UE 102 (e.g., events 302, 304, 324, and / or 326). Block 825 can occur before, during, or after any block described above.

[0124] Fig. 8B is a flow diagram of an example method 800B similar to the method 800A, except that the method 800B includes blocks 814 and 816B instead of block 816A. At block 814, the BS 104 transmits a security activation command to the UE 102. At block 816B, the BS 104 activates security protection for communicating MAC CE(s) with the UE 102 in response to transmitting the security activation command.

[0125] Fig. 9A illustrates an example method 900A, which is performed by a UE 102. The method 900A begins at block 916, where the UE 102 activates security protection for communicating MAC CE(s) with a RAN 105. At block 930, the UE 102 determines to transmit a MAC CE. At block 932, the UE 102 performs security protection for the MAC CE to generate a security protected MAC CE. At block 922, the UE 102 transmits the security-protected MAC CE to the RAN 105.

[0126] Fig. 9B is a flow diagram of an example method 900B similar to the method 900A, except that the method 900B includes blocks 934 and 926. At block 934, the UE 102 determines whether security protection is applied to the MAC CE. If security protection is applied to the MAC CE (i.e. , “Yes” branch of block 934), the flow proceeds to blocks 932 and 922. Otherwise, if security protection is not applied to the MAC CE (i.e., “No” branch of block 934), the flow proceeds to block 926. At block 926, the UEPatent Application Attorney Docket Number 0683-124-WO102 transmits the MAC CE to the RAN 105 without applying security protection to the UL MAC CE.

[0127] Fig. 10A illustrates an example method 1000A, which is performed by a BS 104. The method 1000A begins at block 1016, where the BS 104 activates security protection for communicating MAC CE(s) with a UE 102. At block 1030, the BS 104 determines to transmit a MAC CE. At block 1032, the BS 104 performs security protection for the MAC CE to generate a security protected MAC CE. At block 1020, the BS 104 transmits the security-protected MAC CE to the UE 102.

[0128] Fig. 10B is a flow diagram of an example method 1000B similar to the method 1000A, except that the method 1000B includes blocks 1034 and 1024. At block 1034, the BS 104 determines whether security protection is applied to the MAC CE. If security protection is applied to the MAC CE (i.e. , “Yes” branch of block 1034), the flow proceeds to blocks 1032 and 1020. Otherwise, if security protection is not applied to the MAC CE (i.e., “No” branch of block 1034), the flow proceeds to block 1024. At block 1024, the BS 104 transmits the MAC CE to the UE 102 without applying security protection to the DL MAC CE.

[0129] Fig. 11A illustrates an example method 1100A, which is performed by a UE 102. The method 1100A begins at block 916. At block 1120, the UE 102 receives a security-protected MAC CE from the RAN 105. At block 1136, the UE 102 performs security operation for the MAC CE to obtain a (plain-text) MAC CE and / or verify validity of the MAC CE. At block 1138, the UE 102 applies the MAC CE. That is, the UE 102 at block 1138 performs one or more actions in accordance with the MAC CE.

[0130] In some implementations, the security-protected MAC CE includes an encrypted MAC CE. In such implementations, the security operation includes decryption and the UE 102 decrypts the encrypted MAC CE to obtain the plain-text MAC CE. In some implementations, the security-protected MAC CE includes a non-encrypted MAC CE and a MAC-I for the MAC CE. In such implementations, the security-operation includes an integrity check, and the UE 102 performs an integrity check for the nonencrypted MAC CE based on the MAC-I. If the UE verifies the MAC-I is valid, the UEPatent Application Attorney Docket Number 0683-124-WO102 applies the non-encrypted MAC CE. Otherwise, if the UE 102 verifies the MAC-I is invalid, the UE 102 ignores or discards the MAC CE. Alternatively or additionally, the UE 102 determines a failure and / or performs a failure recovery procedure with the BS 104 to recover the failure.

[0131] Fig. 11B is a flow diagram of an example method 1100B similar to the method 1100A, except that the method 1100B includes blocks 1140 and 1134. At block 1140, the UE 102 receives a MAC CE from the RAN 105 (e.g., event 320 or 324). At block 1134, the UE 102 determines whether security protection is applied to the MAC CE. If security protection is applied to the MAC CE (i.e., “Yes” branch of block 1134), the flow proceeds to blocks 1136 and 1138. Otherwise, if security protection is not applied to the MAC CE (i.e., “No” branch of block 1134), the flow skips block 1136 and proceeds to block 1138.

[0132] Fig. 12A illustrates an example method 1200A, which is performed by a BS 104. The method 1200A begins at block 1016. At block 1222, the BS 104 receives a MAC CE from the UE 102. At block 1236, the BS 104 performs security operation for the MAC CE to obtain a (plain-text) MAC CE and / or verify validity of the MAC CE. At block 1242, the BS 104 performs an operation in response to or based on the MAC CE.

[0133] Fig. 12B is a flow diagram of an example method 1200B similar to the method 1100A, except that the method 1200B includes blocks 1241 and 1234. At block 1241, the BS 104 receives a MAC CE from the UE 102 (e.g., event 320 or 324). At block 1234, the BS 104 determines whether security protection is applied to the MAC CE. If security protection is applied to the MAC CE (i.e., “Yes” branch of block 1234), the flow proceeds to blocks 1236 and 1242. Otherwise, if security protection is not applied to the MAC CE (i.e., “No” branch of block 1234), the flow skips block 1236 and proceeds to block 1242.

[0134] Fig. 13A illustrates an example method 1300A, which is performed by a UE 102. The method 1300A begins at block 1306, where the UE 102 receives a security mode command from a RAN 105. At block 1308, the UE 102 obtains at least one first security key in response to the security mode command. At block 1316A, the UE 102Patent Application Attorney Docket Number 0683-124-WOobtains at least one second security key in response to the security mode command. At block 1394, the UE 102 communicates security-protected data with the RAN 105, using the at least one first security key. At block 1321 A, the UE 102 communicates security-protected MAC CEs with the RAN 105, using the at least second security key (e.g., events 320 and / or 322). The flow may proceed to block 725 as described for Fig. 7A.

[0135] In some implementations, the UE 102 derives the at least one second security key in response to the security mode command. In other implementations, the UE 102 receives the at least one second security key in the security mode command. In some implementations, the at least one first security key includes a first integrity key and / or a first encryption key. In some implementations, the at least one second security key includes a second integrity key and / or a second encryption key.

[0136] Fig. 13B is a flow diagram of an example method 1300B similar to the method 1300A, except that the method 1300B includes blocks 714 and 1316B instead of block 1316A. The UE 102 performs block 714 as described for Fig. 7B. At block 1316B, the UE 102 obtains at least one second security key in response to the security activation command. In some implementations, the UE 102 derives the at least one second security key in response to the security activation command. In other implementations, the UE 102 receives the at least one second security key in the security activation command.

[0137] Fig. 13C is a flow diagram of an example method 1300C similar to the method 1300A, except that the method 1300C includes block 1321C instead of blocks 1316A and 1321 A. At block 1321 C, the UE 102 communicates security-protected MAC CEs with the RAN 105, using the at least one first security key (e.g., events 320 and / or 322).

[0138] Fig. 14A illustrates an example method 1400A, which is performed by a BS 104. The method 1400A begins at block 1406, where the BS 104 transmits a security mode command to a UE 102. At block 1408, the BS 104 obtains at least one first security key in response to transmitting the security mode command. The BS 104 may perform block 814 as described for Fig. 8B. At block 1416, the BS 104 obtains atPatent Application Attorney Docket Number 0683-124-WOleast one second security key. At block 1494, the BS 104 communicates security-protected data with the UE 102, using the at least one first security key. At block 1421 A, the BS 104 communicates security-protected MAC CEs with the UE 102, using the at least one second security key (e.g., events 320 and / or 322). The flow may proceed to block 825 as described for Fig. 8A. In some implementations, the BS 104 obtains the at least one second security key in block 1408, as described for Fig. 3A or Fig. 3B.

[0139] In some implementations, the BS 104 derives the at least one second security key in response to transmitting the security activation command. In some alternative implementations, the BS 104 obtains (e.g., derives) the at least one second security key before transmitting the security activation command. In cases where block 814 is omitted, the BS 104 obtains the at least one second security key in response to or before transmitting the security mode command to the UE. In some implementations, the at least one first security key includes a first integrity key and / or a first encryption key. In some implementations, the at least one second security key includes a second integrity key and / or a second encryption key.

[0140] Fig. 14B is a flow diagram of an example method 1400B similar to the method 1400A, except that the method 1400B includes block 1421B instead of blocks 1416A and 1421A. At block 1421 B, the BS 104 communicates security-protected MAC CEs with the UE 102, using the at least one first security key (e.g., events 320 and / or 322).

[0141] Fig. 15 is a flow diagram of an example method 1500, which can be performed by a RAN node (e.g., the BS 104). The method 1500 begins at block 1570, where the RAN node transmits to a UE 102 a first message indicating a secure algorithm to be used to protect a MAC CE. At block 1572, the RAN node communicates, with the UE 102, a security protected MAC CE based on the secure algorithm.

[0142] Fig. 16 is a flow diagram of an example method 1600, which can be performed by a UE 102. The method 1600 begins at block 1670, where the UE 102 receives, from a RAN node, a first message indicating a secure algorithm to be used toPatent Application Attorney Docket Number 0683-124-WOprotect a MAC CE. At block 1672, the UE 102 communicates, with the RAN node, a security protected MAC CE based on the secure algorithm.

[0143] The descriptions and example implementations described in an earlier figure can apply to a later figure or vice versa, if applicable. Generally speaking, description for one of the above figures can apply to another of the above figures.Examples, implementations and methods described above can be combined, if there is no conflict. An event or block described above can be optional or omitted. For example, an event or block with dashed lines in the figures can be optional. The description described from the perspective of the receiving node also applies to the sending node. For example, a description that a receiving node (e.g., DU) receives a message from a sending node (e.g., CU) may be replaced by the sending node sending a message to the receiving node. Similarly, a description that a receiving node (e.g., CU) receives a message from a sending node (e.g., DU) may be replaced by the sending node sending a message to the receiving node.

[0144] In some implementations, “message” is used and can be replaced by “information element (IE)”, and vice versa. In some implementations, “IE” is used and can be replaced by “field”, and vice versa. In some implementations, “configuration” can be replaced by “configurations” or “configuration parameters”, and vice versa. In some implementations, “activate” can be replaced by “enable” or “configure”, and vice versa. In some implementations, “deactivate” can be replaced by “disable” or “release”, and vice versa. In some implementations, “applied to” can be replaced by “configured for” or “activated for”, and vice versa. In some implementations, “secure” can be replaced by “security”, and vice versa.

[0145] A user device in which the techniques of this disclosure can be implemented (e.g., the UE 102) can be any suitable device capable of wireless communications such as a smartphone, a tablet computer, a laptop computer, a mobile gaming console, a point-of-sale (POS) terminal, a health monitoring device, a drone, a camera, a media-streaming dongle or another personal media device, a wearable device such as a smartwatch, a wireless hotspot, a femtocell, or a broadband router. Further, the user device in some cases may be embedded in an electronic system suchPatent Application Attorney Docket Number 0683-124-WOas the head unit of a vehicle or an advanced driver assistance system (ADAS). Still further, the user device can operate as an internet-of-things (loT) device or a mobile-internet device (MID). Depending on the type, the user device can include one or more general-purpose processors, a computer-readable memory, a user interface, one or more network interfaces, one or more sensors, etc.

[0146] Certain embodiments are described in this disclosure as including logic or a number of components or modules. Modules may be software modules (e.g., code, or machine-readable instructions stored on non-transitory machine-readable medium) or hardware modules. A hardware module is a tangible unit capable of performing certain operations and may be configured or arranged in a certain manner. A hardware module can comprise dedicated circuitry or logic that is permanently configured (e.g., as a special-purpose processor, such as a field programmable gate array (FPGA) or an application-specific integrated circuit (ASIC), a digital signal processor (DSP), etc.) to perform certain operations. A hardware module may also comprise programmable logic or circuitry (e.g., as encompassed within a general-purpose processor or other programmable processor) that is temporarily configured by software to perform certain operations. The decision to implement a hardware module in dedicated and permanently configured circuitry, or in temporarily configured circuitry (e.g., configured by software) may be driven by cost and time considerations.

[0147] When implemented in software, the techniques can be provided as part of the operating system, a library used by multiple applications, a particular software application, etc. The software can be executed by one or more general-purpose processors or one or more special-purpose processors.

[0148] Upon reading this disclosure, those of skill in the art will appreciate still additional and alternative structural and functional designs for handling mobility between base stations through the principles disclosed herein. Thus, while particular embodiments and applications have been illustrated and described, it is to be understood that the disclosed embodiments are not limited to the precise construction and components disclosed herein. Various modifications, changes and variations, which will be apparent to those of ordinary skill in the art, may be made in the arrangement,Patent Application Attorney Docket Number 0683-124-WOoperation and details of the method and apparatus disclosed herein without departing from the spirit and scope defined in the appended claims.

[0149] The detailed descriptions do not preclude other embodiments within the scope of the appended claims. The embodiments are not limited to the abovedescribed configurations but may be extended to other arrangements.

[0150] Reference throughout this section to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment. Thus, the appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout the specification are not necessarily all referring to the same embodiment. Further, the particular features, structures or characteristics may be combined in any suitable manner in one or more embodiments.

[0151] Numerical adjectives “first”, “second”, and “third” do not imply any order (are not ordinals) but are markers to distinguish separate instances of similar elements.References to the singular (e.g., “a” or “an”, “the”) should include the plural unless clearly indicated otherwise.

[0152] As used herein, a phrase referring to “at least one of’ or “one or more of’ a list of items refers to any combination of those items, including single members. For example, “at least one of: a, b, or c” is intended to cover the possibilities of: a only, b only, c only, a combination of a and b, a combination of a and c, a combination of b and c, and a combination of a and b and c.

[0153] Although the features and elements of the present embodiments are described in the embodiments in particular combinations, each feature or element can be used alone without the other features and elements of the embodiments or in various combinations with or without other features and elements disclosed herein. The methods or flowcharts may be implemented in a computer program, software or firmware tangibly embodied in a computer-readable storage medium for execution by a specifically programmed computer or processor.

Claims

1. Patent Application Attorney Docket Number 0683-124-WOWHAT IS CLAIMED IS:

1. A method (300A, 1500) for wireless communication performed by a radio access network, RAN, node (104), the method comprising:communicating (304), to a user equipment, UE, (102), a first non-security protected medium access control, MAC, control element, CE, before security protection is activated;transmitting (1570) to the UE, a first message indicating one or more secure algorithms to be used to protect a MAC CE; andcommunicating (1572), with the UE, a second security protected MAC CE based on the one or more secure algorithms.

2. The method of claim 1 , wherein the communicating the second security protected MAC CE includes at least one of:transmitting, to the UE, the second security protected MAC CE; or receiving, from the UE, the second security protected MAC CE.

3. The method of claim 1 or 2, further comprising communicating (825), with the UE, a third non-security protected MAC CE after security protection is activated.

4. The method of any of claims 1 to 3, wherein the one or more secure algorithms comprise a first encryption algorithm for data security protection that is different than a second encryption algorithm for MAC CE security protection.

5. The method of any of claims 1 to 3, further comprising transmitting (892, 308, 310, 318) a security mode command to the UE to configure the one or more secure algorithms to activate data security protection and MAC CE security protection.

6. The method of any of claims 1 to 3, wherein a length of a second message authentication code for integrity, MAC-I for the second security protected MAC CE is less than a first MAC-I for data security protection.Patent Application Attorney Docket Number 0683-124-WO7. The method of claim 4, wherein a length of a second security key for the second encryption algorithm is less than a length of a first security key for the first encryption algorithm.

8. The method of any of claims 1 to 7, further comprising receiving, from the UE, a second message in response to the first message,wherein the first message is a security mode command and the second message is a security mode complete.

9. The method of any of claims 1 to 8, wherein the first message specifies at least one higher layer parameter to be inputted to the one or more secure algorithms.

10. The method of any of claims 1 to 9, further comprising transmitting (314), to the UE, a third message to trigger the UE to use the one or more secure algorithms for the second security protected MAC CE.

11. A method (300A, 1600) for wireless communication performed by user equipment, UE (102), the method comprising:communicating (304), to a radio access network, RAN, node (104) a first nonsecurity protected medium access control, MAC, control element, CE, before security protection is activated;receiving (1670) from the RAN node, a first message indicating one or more secure algorithms to be used to protect a MAC CE; andcommunicating (1672), with the RAN node, a second security protected MAC CE based on the one or more secure algorithms.

12. The method of claim 11 , wherein the communicating the second security protected MAC CE includes at least one of:receiving, from the RAN node, the second security protected MAC CE; or transmitting, to the RAN node, the second security protected MAC CE.Patent Application Attorney Docket Number 0683-124-WO13. The method of claim 11 or 12, further comprising communicating (825), with the RAN node, a third non-security protected MAC CE after security protection is activated.

14. The method of any of claims 11 to 13, wherein the one or more secure algorithms comprise a first encryption algorithm for data security protection that is different than a second encryption algorithm for MAC CE security protection.

15. The method of any of claims 11 to 13, further comprising receiving (792, 308, 310, 318) a security mode command from the RAN node to configure the one or more secure algorithms to activate data security protection and MAC CE security protection.

16. The method of any of claims 11 to 13, wherein a length of a second message authentication code for integrity, MAC-I for the second security protected MAC CE is less than a first MAC-I for data security protection.

17. The method of claim 14, wherein a length of a second security key for the second encryption algorithm is less than a length of a first security key for the first encryption algorithm.

18. The method of any of claims 11 to 17, further comprising transmitting, to the RAN node, a second message in response to the first message,wherein the first message is a security mode command and the second message is a security mode complete.

19. The method of any of claims 11 to 18, wherein the first message specifies at least one higher layer parameter to be inputted to the one or more secure algorithms.Patent Application Attorney Docket Number 0683-124-WO20. The method of any of claims 11 to 19, further comprising receiving (314) a third message from the RAN node to trigger the UE to use the one or more secure algorithms for the second security protected MAC CE.

21. A communication device (102, 104) comprising a processor (132, 142) and a transceiver (134, 144) configured to cooperatively execute the methods of claims 1 to 20.

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