Procedures enabling privacy for WTRU using pc5 communication

Abstract

To avoid tracking and / or identification of a source wireless transmit / receive unit (WTRU) by any other WTRUs.SOLUTION: A method for use in an ongoing vehicle-to-everything (V2X) session includes communicating between a source WTRU and a peer WTRU on the basis of a source layer 2 (L2) identifier (ID). On a condition that a trigger event occurs, the source WTRU generates a new source L2 ID, communicates the new source L2 ID to the peer WTRU, receives from the peer WTRU a message that responds to the new source L2 ID, and communicates between the source WTRU and the peer WTRU on the basis of the new source L2 ID.SELECTED DRAWING: Figure 15

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Patent Application No. 62 / 688,614, filed June 22, 2018, U.S. Provisional Patent Application No. 62,741,962, filed October 5, 2018, and U.S. Provisional Patent Application No. 62,812,676, filed March 01, 2019, which are hereby incorporated by reference in their entireties for all purposes. [Background technology]

[0002] Vehicle-to-Everything (V2X) communications can include communications between vehicles and other suitable entities, such as vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), vehicle-to-pedestrian (V2P), and vehicle-to-network (V2N) communications. V2X can also refer to standards related to such communications. PC5 is an interface for communicating between V2X devices as a type of sidelink or proximity services (ProSe) direct communications. Summary of the Invention

[0003] This Summary is provided to introduce a selection of concepts in a simplified form as a prelude to the more detailed description presented later. This Summary is not intended to identify key or essential features, nor is it intended to delineate the scope of the claimed subject matter. The embodiments depicted in the various figures are related, and features therein may be combined, unless otherwise stated.

[0004] In one embodiment, a method for use in an ongoing vehicle-to-everything (V2X) session includes updating at least a source wireless transmit / receive unit (WTRU) with privacy parameters. The method includes communicating between the source wireless transmit / receive unit (WTRU) and a peer WTRU based on an existing Layer 2 (L2) identifier (ID). When a trigger event occurs, the source WTRU generates a new source L2ID for the source WTRU, communicates the new source L2ID to the peer WTRU, receives a message from the peer WTRU in response to the new source L2ID, and communicates between the source WTRU and the peer WTRU based on the new source L2ID.

[0005] In one embodiment, the peer WTRU L2ID is also changed. The peer WTRU changes its L2ID, and the source WTRU receives the new peer L2ID from the peer WTRU. This reception of the new peer L2ID by the source WTRU may occur after the source WTRU communicates the new source L2ID to the peer WTRU. The source WTRU and peer WTRU can then communicate with each other based on the new source L2ID and the new peer L2ID.

[0006] In one embodiment, the source and peer L2IDs, as well as the session ID for communication between the source WTRU and the peer WTRU, may be updated. The session ID is updated using the most significant byte (MSB) and least significant byte (LSB) contributions. The source WTRU generates a new MSB of the session ID used to communicate with the peer WTRU and also generates a new source L2ID. The source WTRU communicates the new MSB of the session ID along with communicating the new source L2ID to the peer WTRU. Along with receiving the new peer L2ID, the source WTRU receives a new least significant byte (LSB) of the session ID from the peer WTRU. The source WTRU and peer WTRU then update the session ID based on the new source L2ID and the new peer L2ID. The session ID is then communicated to the client, which communicates a new session ID that contains the new MSB and the new LSB of the session ID.

[0007] In one embodiment, the function of communicating the new source L2 ID to the peer WTRU includes communicating using one of a keep-alive procedure, a privacy procedure, or another communication procedure used between the source WTRU and the peer WTRU. The source WTRU may communicate the new source L2 ID over a layer above the source WTRU prior to communicating with the peer WTRU based on the new source L2 ID.

[0008] In one embodiment, the triggering events that cause at least a change in the source L2ID may include any of the following: an expiring timer, a higher layer or application layer of the V2X application requesting a new L2ID, a determination that the source WTRU has moved to a new geographical area, the source WTRU receiving new provisioning parameters from a V2X control function or V2X application server, or the source WTRU receiving a request to change the L2ID from a peer WTRU. The session ID may be a security context session ID. The communication between the source WTRU and the peer WTRU may include communication over a PC5 reference link.

[0009] In one embodiment, a source wireless transmit / receive unit (WTRU) may include circuitry including a transmitter, a receiver, a processor, and a memory. The WTRU's circuitry is configured to communicate between the source WTRU and a peer WTRU based on a Layer 2 (L2) identifier (ID) using the transmitter and receiver. On the condition that a trigger event occurs, the source WTRU generates a new source L2 ID for the source WTRU, communicates the new source L2 ID to the peer WTRU, and communicates with the peer WTRU based on the new source L2 ID.

[0010] In an embodiment where the peer WTRU and the source WTRU have a change in L2ID, the source WTRU may receive the new peer L2ID after communicating the new source L2ID to the peer WTRU. The source WTRU may then communicate with the peer WTRU based on the new source L2ID and the new peer L2ID.

[0011] In one embodiment, a computer readable storage medium may contain instructions that, when executed by a computer, cause the computer to perform any of the methods described herein. [Brief description of the drawings]

[0012] A more detailed understanding may be had from the following description, given by way of example in conjunction with the accompanying drawings, in which like reference numbers indicate similar elements and in which:

[0013] [Figure 1A] FIG. 1 is a system diagram illustrating an example communication system in which one or more disclosed embodiments may be implemented. [Figure 1B] 1A is a system diagram illustrating an example of a wireless transmit / receive unit (WTRU) that may be used within the communications system illustrated in FIG. 1A, according to one embodiment. [Figure 1C] 1B is a system diagram illustrating an example radio access network (RAN) and an example core network (CN) that may be used within the communications system illustrated in FIG. 1A, according to one embodiment. [Figure 1D] FIG. 1B is a system diagram illustrating a further exemplary RAN and a further exemplary CN that can be used within the communication system illustrated in FIG. 1A, according to one embodiment. [Diagram 2] 13 shows an example of the security context ID format of the PDCP header for one-to-one communication. [Diagram 3] 13 is a sequence chart outlining an example of changing a source WTRU L2 ID. [Figure 4] 1 is a sequence chart showing an example of privacy parameter provisioning. [Diagram 5]1 is a sequence chart showing an example of such a direct link setup procedure. [Figure 6] 13 is a sequence chart illustrating an example of exchanging a new L2 identifier using an updated keep-alive procedure. [Figure 7] 11 is a sequence chart illustrating an example of a source and peer WTRU updating their L2 IDs during the same procedure. [Figure 8] 11 is a sequence chart showing an example of a privacy procedure for a single L2 ID change. [Figure 9] 11 is a sequence chart illustrating an example of source WTRU and peer WTRU L2IDs being updated during the same procedure. [Figure 10] 11 is a sequence chart illustrating an example of a peer WTRU triggering an L2 ID change procedure. [Figure 11] 11 is a sequence chart illustrating an example procedure by which a source WTRU configures a peer WTRU and a source WTRU L2 ID update. [Figure 12] 11 is a sequence chart illustrating privacy timer value and seed configuration. [Figure 13] 11 is a message sequence chart illustrating the case where both WTRUs exchange a new portion of the session ID using privacy procedures. [Figure 14] 1 is a message sequence chart illustrating the exchange of a new L2 ID using the enhanced rekey procedure. [Figure 15] FIG. 1 is a flow diagram of a method using at least elements of a procedure for changing a source L2 ID. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] FIG. 1A illustrates an example communication system 100 in which one or more disclosed embodiments may be implemented. The communication system 100 may be a multi-access system that provides content, such as voice, data, video, messaging, broadcasts, etc., to multiple wireless users. The communication system 100 may enable multiple wireless users to access such content through sharing of system resources, including wireless bandwidth. For example, the communication system 100 may employ one or more channel access schemes, such as Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal FDMA (OFDMA), Single Carrier FDMA (SC-FDMA), Zero-Tailed Unique Word DFT-Spread OFDM (ZT UW DTS-s OFDM), Unique Word OFDM (UW-OFDM), Resource Block Filtered OFDM, Filter Bank Multi-Carrier (FBMC), etc.

[0015] 1A, communications system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, RANs 104 / 113, ONs 106 / 115, a public switched telephone network (PSTN) 108, the Internet 110, and other networks 112, although it will be understood that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network elements. Each of WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and / or communicate in a wireless environment. By way of example, the WTRUs 102a, 102b, 102c, 102d (any of which may be referred to as a “station” and / or “STA”) may be configured to transmit and / or receive wireless signals and may be used in a variety of applications, including user equipment (UE), mobile stations, fixed or mobile subscriber units, subscription-based units, pagers, mobile phones, personal digital assistants (PDAs), smartphones, laptops, netbooks, personal The WTRUs may include computers, wireless sensors, hotspot or Mi-Fi devices, Internet of Things (IoT) devices, watches or other wearables, head mounted displays (HMDs), vehicles, drones, medical equipment and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in the context of an industrial and / or automated processing chain), consumer electronics devices, device networks operating over commercial and / or industrial wireless, etc. Any of the WTRUs 102a, 102b, 102c, and 102d may be referred to interchangeably as a UE.

[0016] The communication system 100 may also include a base station 114a and / or a base station 114b. Each of the base stations 114a, 114b may be any type of device configured to wirelessly interface with at least one of the WTRUs 102a, 102b, 102c, 102d to facilitate access to one or more communication networks, such as the CN 106 / 115, the Internet 110, and / or other networks 112. By way of example, the base stations 114a, 114b may be a base transceiver station (BTS), a Node-B, an eNode-B, a Flome Node-B, a Flome eNode-B, a gNB, a NR Node-B, a site controller, an access point (AP), a wireless router, etc. Although the base stations 114a, 114b are each shown as a single element, it will be understood that the base stations 114a, 114b may include any number of interconnected base stations and / or network elements.

[0017] The base station 114a may be part of the RAN 104 / 113, which may also include other base stations and / or network elements (not shown), such as a base station controller (BSC), a radio network controller (RNC), relay nodes, etc. The base station 114a and / or the base station 114b may be configured to transmit and / or receive wireless signals on one or more carrier frequencies, which may be referred to as a cell (not shown). These frequencies may be licensed spectrum, unlicensed spectrum, or a combination of licensed and unlicensed spectrum. A cell may provide wireless service coverage to a particular geographic area that may be relatively fixed or may change over time. A cell may be further divided into cell sectors. For example, the cell associated with the base station 114a may be divided into three sectors. Thus, in one embodiment, the base station 114a may include three transceivers, i.e., one for each sector of the cell. In one embodiment, the base station 114a may employ multiple-input multiple-output (MIMO) technology and may utilize multiple transceivers for each sector of the cell. For example, beamforming can be used to transmit and / or receive signals in a desired spatial direction.

[0018] The base stations 114a, 114b may communicate with one or more WTRUs 102a, 102b, 102c, 102d over an air interface 116, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, centimeter wave, microwave, infrared (IR), ultraviolet (UV), visible light, etc.). The air interface 116 may be established using any suitable radio access technology (RAT).

[0019] More specifically, as noted above, the communications system 100 may be a multiple access system and may employ one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, etc. For example, the base stations 114a and WTRUs 102a, 102b, 102c of the RAN 104 / 113 may implement a radio technology, such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may establish the air interface 115 / 116 / 117 using Wideband CDMA (WCDMA). WCDMA is a type of high-speed packet access (GPA) based on cellular data. The communication protocols may include, for example, High Speed ​​Downlink (DL) Packet Access (FISDPA) and / or Evolved HSPA (FISPA+). HSPA may include High Speed ​​Downlink (DL) Packet Access (FISDPA) and / or High Speed ​​Uplink Packet Access (HSUPA).

[0020] In one embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which may establish the air interface 116 using Long Term Evolution (LTE) and / or LTE-Advanced (LTE-A) and / or LTE-Advanced Pro (LTE-A Pro).

[0021] In one embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as NR radio access, which may establish the air interface 116 using New Radio (NR).

[0022] In one embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement multiple radio access technologies. For example, the base station 114a and the WTRUs 102a, 102b, 102c may implement LTE radio access and NR radio access together, e.g., using a dual connectivity (DC) principle. Thus, the air interface utilized by the WTRUs 102a, 102b, 102c may be characterized by multiple types of radio access technologies and / or transmissions sent to and from multiple types of base stations (e.g., eNBs and gNBs).

[0023] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement a wireless technology such as IEEE 802.11 (i.e., Wireless Fidelity (WiFi), IEEE 802.16 (i.e., Global Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 1X, CDMA2000EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile Communications (GSM), Enhanced Data Rates for GSM Evolution (EDGE), GSM EDGE (GERAN), or the like.

[0024] 1A may be, for example, a wireless router, a Flome Node-B, a Flome eNode-B, or an access point and may utilize any suitable RAT to facilitate wireless connectivity in a local area, such as an office, a home, a vehicle, a campus, an industrial facility, an air corridor (e.g., for use by drones), a road, etc. In one embodiment, the base station 114b and the WTRUs 102c, 102d may implement a wireless technology, such as IEEE 802.11, to establish a wireless local area network (WLAN). In one embodiment, the base station 114b and the WTRUs 102c, 102d may implement a wireless technology, such as IEEE 802.15, to establish a wireless personal area network (WPAN). In yet another embodiment, the base station 114b and the WTRUs 102c, 102d may establish a picocell or a femtocell utilizing a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.). As shown in FIG. 1A, the base station 114b may be directly connected to the Internet 110. Thus, the base station 114b may not need to access the Internet 110 via the CN 106 / 115.

[0025] The RAN 104 / 113 may communicate with the CN 106 / 115, which may provide voice, data, applications, and / or Voice over Internet Protocol (VoIP) communications to one or more WTRUs 102a, 102b, 102c, 102d. RAN 104 / 113 may be any type of network configured to provide a RAN (Router Area Network) service. The data may include various quality of service (QoS) requirements, such as different throughput requirements, delay requirements, error tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, etc. The CN 106 / 115 may provide call control, charging services, mobile location-based services, prepaid calling, Internet connectivity, video distribution, etc., and / or perform high level security functions such as user authentication. Although not shown in FIG. 1A, it will be understood that the RAN 104 / 113 and / or the CN 106 / 115 may directly or indirectly communicate with other RANs that use the same RAT as the RAN 104 / 113 or a different RAT. For example, in addition to being connected to the RAN 104 / 113, which may utilize NR radio technology, the CN 106 / 115 may also communicate with another RAN (not shown) that uses GSM, UMTS, CDMA2000, WiMAX, E-UTRA, or WiFi radio technology.

[0026] The CN 106 / 115 may also serve as a gateway for the WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the Internet 110, and / or other networks 112. The PSTN 108 may include a circuit-switched telephone network providing plain old telephone service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices that use common communication protocols such as Transmission Control Protocol (TCP), User Datagram Protocol (UDP), and / or Internet Protocol (IP) of the TCP / IP Internet protocol suite. The networks 112 may include wired and / or wireless communication networks owned and / or operated by other service providers. For example, the networks 112 may include another CN connected to one or more RANs, which may use the same RAT as the RANs 104 / 113 or a different RAT.

[0027] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communications system 100 may include multi-mode capabilities (e.g., the WTRUs 102a, 102b, 102c, 102d may include multiple transceivers for communicating with different wireless networks over different wireless links). For example, the WTRU 102c shown in FIG. 1A may be configured to communicate with a base station 114a, which may employ a cellular-based wireless technology, and with a base station 114b, which may employ an IEEE 802 wireless technology.

[0028] 1B is a system diagram illustrating an example WTRU 102. As shown in FIG. 1B, the WTRU 102 may include, among other things, a processor 118, a transceiver 120, a transmit / receive element 122, a speaker / microphone 124, a keypad 126, a display / touchpad 128, non-removable memory 130, removable memory 132, a power source 134, a global positioning system (GPS) chipset 136, and / or other peripherals 138. It will be understood that the WTRU 102 may include any subcombination of the foregoing elements while remaining consistent with an embodiment.

[0029] The processor 118 may be a general-purpose processor, a special purpose processor, a conventional processor, a digital signal processor (DSP), multiple microprocessors, one or more microprocessors associated with a DSP core, a controller, a microcontroller, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) circuit, other types of integrated circuits (ICs), a state machine, etc. The processor 118 may perform signal coding, data processing, power control, input / output processing, and / or any other functionality that enables the WTRU 102 to operate in a wireless environment. The processor 118 may be coupled to the transceiver 120, which may be coupled to the transmit / receive element 122. While FIG. 1B depicts the processor 118 and the transceiver 120 as separate components, the processor 118 and the transceiver 120 may be integrated into an electronic package. It will be appreciated that the various components may be integrated together on a chip.

[0030] The transmit / receive element 122 may be configured to transmit signals to or receive signals from a base station (e.g., base station 114a) over the air interface 116. For example, in one embodiment, the transmit / receive element 122 may be an antenna configured to transmit and / or receive RF signals. In one embodiment, the transmit / receive element 122 may be an emitter / detector configured to transmit and / or receive IR, UV, or visible light signals, for example. In yet another embodiment, the transmit / receive element 122 may be configured to transmit and / or receive both RF and light signals. It will be appreciated that the transmit / receive element 122 may be configured to transmit and / or receive any combination of wireless signals.

[0031] 1B as a single element, the WTRU 102 may include any number of transmit / receive elements 122. More specifically, the WTRU 102 may employ MIMO technology. Thus, in one embodiment, the WTRU 102 may include two or more transmit / receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals over the air interface 116.

[0032] The transceiver 120 may be configured to modulate signals transmitted by the transmit / receive element 122 and demodulate signals received by the transmit / receive element 122. As mentioned above, the WTRU 102 may have multi-mode capabilities. Thus, the transceiver 120 may include multiple transceivers to enable the WTRU 102 to communicate via multiple RATs, such as, for example, NR and IEEE 802.11.

[0033] The processor 118 of the WTRU 102 may be coupled to and may receive user input data from the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128 (e.g., a liquid crystal display (LCD) display unit or an organic light emitting diode (OLED) display unit). The processor 118 may also output user data to the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128. Additionally, the processor 118 may access information from and store data in any type of suitable memory, such as non-removable memory 130 and / or removable memory 132. The non-removable memory 130 may include random access memory (RAM), read only memory (ROM), a hard disk, or any other type of memory storage device. The removable memory 132 may include a subscriber identity module (SIM) card, a memory stick, a secure digital (SD) memory card, or the like. In other embodiments, the processor 118 may access information from and store data in memory that is not physically located on the WTRU 102, such as a server or home computer (not shown).

[0034] The processor 118 may receive power from the power source 134 and may be configured to distribute and / or control the power to other components within the WTRU 102. The power source 134 may be any suitable device for providing power to the WTRU 102. For example, the power source 134 may include one or more dry batteries (e.g., nickel cadmium (NiCd), nickel zinc (NiZn), nickel metal hydride (NiMH), lithium ion (Li-ion), etc.), solar cells, fuel cells, etc.

[0035] The processor 118 may also be coupled to a GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) regarding the current location of the WTRU 102. In addition to, or instead of, information from the GPS chipset 136, the WTRU 102 may The U 102 may receive location information from a base station (e.g., base stations 114a, 114b) over the air interface 116 and / or may determine its location based on the timing of signals received from two or more nearby base stations. It will be appreciated that the WTRU 102 may obtain location information by way of any suitable location determination method while remaining consistent with an embodiment.

[0036] The processor 118 may further be coupled to other peripherals 138, which may include one or more software and / or hardware modules that provide additional features, functionality, and / or wired or wireless connectivity. For example, the peripherals 138 may include an accelerometer, an e-compass, a satellite transceiver, a digital camera (for photos and / or videos), a universal serial bus (USB) port, a vibration device, a television transceiver, a hands-free headset, a Bluetooth module, a frequency modulation (FM) radio unit, a digital music player, a media player, a video game player module, an Internet browser, a virtual reality and / or augmented reality (VR / AR) device, an activity tracker, and / or the like. The peripherals 138 may include one or more sensors, which may be one or more of a gyroscope, an accelerometer, a Hall effect sensor, a magnetometer, a direction sensor, a proximity sensor, a temperature sensor, a time sensor, a geolocation sensor, an altimeter, a light sensor, a touch sensor, a magnetometer, a barometer, a gesture sensor, a biometric sensor, and / or a humidity sensor.

[0037] The WTRU 102 may include a full-duplex radio where transmission and reception of some or all of the signals (e.g., associated with a particular subframe) on both the UL (e.g., for transmission) and downlink (e.g., for reception) may occur in parallel and / or simultaneously. The full-duplex radio may include an interference management unit 139 to reduce and / or substantially eliminate self-interference either via hardware (e.g., chokes) or a processor (e.g., signal processing via a separate processor (not shown) or processor 118). In one embodiment, the WRTU 102 may include a half-duplex radio for transmission and reception of some or all of the signals (e.g., associated with a particular subframe on either the UL (e.g., for transmission) or downlink (e.g., for reception)).

[0038] 1C is a system diagram illustrating the RAN 104 and the CN 106 according to one embodiment. As mentioned above, the RAN 104 may communicate with the WTRUs 102a, 102b, 102c over the air interface 116 using E-UTRA radio technology. The RAN 104 may also be in communication with the CN 106.

[0039] The RAN 104 may include eNode-Bs 160a, 160b, 160c, although it will be understood that the RAN 104 may include any number of eNode-Bs while remaining consistent with an embodiment. The eNode-Bs 160a, 160b, 160c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In an embodiment, the eNode-Bs 160a, 160b, 160c may implement MIMO technology. Thus, the eNode-B 160a, for example, may use multiple antennas to transmit wireless signals to and / or receive wireless signals from the WTRU 102a.

[0040] Each of the eNode-Bs 160a, 160b, 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the UL and / or DL, etc. As shown in FIG 1C, the eNode-Bs 160a, 160b, 160c may communicate with one another via an X2 interface.

[0041] 1C may include a Mobility Management Entity (MME) 162, a Serving Gateway (SGW) 164, and a Packet Data Network (PDN) Gateway (or PGW) 166. Although each of the foregoing elements is shown as part of the CN 106, it will be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0042] The MME 162 may be connected to each of the eNode-Bs 160a, 160b, 160c in the RAN 104 via an S1 interface and may function as a control node. For example, the MME 162 may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, activating / deactivating bearers, selecting a particular serving gateway during initial attachment of the WTRUs 102a, 102b, 102c, etc. The MME 162 may provide a control plane function for switching between the RAN 104 and other RANs (not shown) that use other radio technologies, such as GSM and / or WCDMA.

[0043] The SGW 164 may be connected to each of the eNode-Bs 160a, 160b, 160c in the RAN 104 via an S1 interface. The SGW 164 may generally route and forward user data packets to and from the WTRUs 102a, 102b, 102c. The SGW 164 may perform other functions, such as fixing the user plane during inter-eNode-B handovers, triggering paging when DL data is available to the WTRUs 102a, 102b, 102c, managing and storing context for the WTRUs 102a, 102b, 102c, etc.

[0044] The SGW 164 may be connected to a PGW 166, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices.

[0045] The CN 106 may facilitate communications with other networks. For example, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to circuit-switched networks, such as the PSTN 108, to facilitate communications between the WTRUs 102a, 102b, 102c and traditional landline communications devices. For example, the CN 106 may include or communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that serves as an interface between the CN 106 and the PSTN 108. Additionally, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers.

[0046] Although the WTRU is depicted in FIGS. 1A-1D as a wireless terminal, in certain representative embodiments it is contemplated that such a terminal may use a wired communications interface (e.g., temporarily or permanently) with the communications network.

[0047] In an exemplary embodiment, the other network 112 may be a WLAN.

[0048] A WLAN in infrastructure basic service set (BSS) mode may have an access point (AP) for the BSS and one or more stations (STAs) associated with the AP. The AP may have access or an interface to a distribution system (DS) or another type of wired / wireless network that carries traffic into and / or out of the BSS. Traffic to a STA that has been sent to a BSS may arrive through the AP and be delivered to the STA. Traffic originating from a STA to a destination outside the BSS may be sent to the AP and delivered to the respective destination. Traffic between STAs in a BSS may be transmitted through the AP. For example, a source STA may transmit traffic to an AP, and the AP may deliver the traffic to a destination STA. Traffic between STAs in a BSS may be considered and / or referred to as peer-to-peer traffic. Peer-to-peer traffic may be transmitted (e.g., directly) between a source STA and a destination STA using a direct link setup (DLS). In certain representative embodiments, the DLS may use 802.11e DLS or 802.11z Tunneled DLS (TDLS). A WLAN using an Independent BSS (IBSS) mode may not have an AP, and STAs (e.g., all STAs) in or using an IBSS may communicate directly with each other. The IBSS communication mode may be referred to herein as an "ad-hoc" communication mode.

[0049] When using 802.11ac infrastructure mode of operation or a similar mode of operation, the AP may transmit beacons on a fixed channel, such as a primary channel. The primary channel may be a fixed width (e.g., 20 MHz wide bandwidth) or a width dynamically set via signaling. The primary channel may be an operating channel of the BSS and may be used by STAs to establish a connection with the AP. In certain representative embodiments, carrier sense multiple access with collision avoidance (CSMA / CA) may be implemented, for example, in an 802.11 system. With CSMA / CA, STAs (e.g., all STAs), including the AP, may sense the primary channel. If the primary channel is detected / sensed and / or determined to be busy by a particular STA, the particular STA may back off. One STA (e.g., only one station) may transmit on a particular BSS at any time.

[0050] High throughput (HT) STAs may use a 40 MHz wide channel for communication, for example, through a combination of a primary 20 MHz channel with adjacent or non-adjacent 20 MHz channels to form a 40 MHz wide channel.

[0051] A Very High Throughput (VHT) STA may support 20 MHz, 40 MHz, 80 MHz, and / or 160 MHz wide channels. A 40 MHz and / or 80 MHz channel may be formed by combining contiguous 20 MHz channels. A 160 MHz channel may be formed by combining eight contiguous 20 MHz channels or by combining two non-contiguous 80 MHz channels. This may be referred to as an 80+80 configuration. For the 80+80 configuration, after channel encoding, the data may pass through a segment parser to split the data into two streams. Inverse Fast Fourier Transform (IFFT) processing, and time domain processing may be performed on each stream separately. The streams may be mapped to two 80 MHz channels, and the data may be transmitted by the transmitting STA. At the receiver of the receiving STA, the above operations for the 80+80 configuration may be reversed, and the combined data may be transmitted to the medium access control (MAC).

[0052] Sub-1 GHz operating modes are supported by 802.11af and 802.11ah. The channel operating bandwidths and carriers are reduced in 802.11af and 802.11ah compared to those used in 802.11n and 802.11ac. 802.11af supports 5 MHz, 10 MHz, and 20 MHz bandwidths in the TV White Space (TVWS) spectrum, while 802.11ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths using non-TVWS spectrum. According to a representative embodiment, 802.11ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths within a macro coverage area. An MTC device may support metered control / machine type communication such as an MTC device. An MTC device may have limited functionality including specific functionality, for example, support for (e.g., support only) a specific bandwidth and / or limited bandwidth. An MTC device may include a battery with a battery life above a threshold (e.g., to maintain a very long battery life).

[0053] WLAN systems that may support multiple channels and channel bandwidths, such as 802.11n, 802.11ac, 802.11af, 802.11ah, include a channel that can be designated as a primary channel. The primary channel may have a bandwidth equal to the largest common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel may be set and / or limited by the STA from among all STAs operating in the BSS that support the smallest bandwidth operating mode. In the 802.11ah example, the primary channel for a STA (such as an MTC-type device) that supports (e.g., only supports) a 1 MHz mode may be 1 MHz wide, even if the AP and other STAs in the BSS support 2 MHz, 4 MHz, 8 MHz, 16 MHz, and / or other channel bandwidth operating modes. Carrier sensing and / or network allocation vector (NAV) setting may depend on the status of the primary channel. For example, if the primary channel is busy because a STA (that only supports a 1 MHz operating mode) is transmitting to the AP, a large portion of the frequency band may remain idle and available.

[0054] In the United States, the available frequency bands for use with 802.11ah are 902MHz to 928MHz. In South Korea, the available frequency bands are 917.5MHz to 923.5MHz. In Japan, the available frequency bands are 916.5MHz to 927.5MHz. The total available bandwidth for 802.11ah is 6MHz to 26MHz depending on the country code.

[0055] 1D is a system diagram illustrating the RAN 113 and the CN 115 according to one embodiment. As mentioned above, the RAN 113 may communicate with the WTRUs 102a, 102b, 102c over the air interface 116 using NR radio technology. The RAN 113 may also be in communication with the CN 115.

[0056] The RAN 113 may include gNBs 180a, 180b, 180c, although it will be understood that the RAN 113 may include any number of gNBs while remaining consistent with an embodiment. The gNBs 180a, 180b, 180c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In an embodiment, the gNBs 180a, 180b, 180c may implement MIMO technology. For example, the gNBs 180a, 108b may utilize beamforming to transmit signals to and / or receive signals from the gNBs 180a, 180b, 180c. Thus, the gNB 180a may transmit wireless signals to and / or receive wireless signals from the WTRU 102a using, for example, multiple antennas. In one embodiment, the gNBs 180a, 180b, 180c may implement carrier aggregation techniques. For example, the gNB 180a may transmit multiple component carriers to the WTRU 102a (not shown). A subset of these component carriers may be on an unlicensed spectrum, and the remaining component carriers may be on a licensed spectrum. In one embodiment, the gNBs 180a, 180b, 180c may implement coordinated multipoint (CoMP) techniques. For example, the WTRU 102a may receive coordinated transmissions from the gNBs 180a and 180b (and / or gNB 180c).

[0057] The WTRUs 102a, 102b, 102c can communicate with the gNBs 180a, 180b, 180c using transmissions associated with scalable numerologies. For example, the OFDM symbol spacing and / or OFDM subcarrier spacing may vary for different transmissions, different cells, and / or different portions of the wireless transmission spectrum. The WTRUs 102a, 102b, 102c can communicate with the gNBs 180a, 180b, 180c using subframes or transmission time intervals (TTIs) of different or scalable lengths (e.g., absolute times of different lengths that include and / or last for different numbers of OFDM symbols).

[0058] The gNBs 180a, 180b, 180c may be configured to communicate with the WTRUs 102a, 102b, 102c in a standalone configuration and / or a non-standalone configuration. In a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c without accessing any other RAN (e.g., eNode-Bs 160a, 160b, 160c, etc.). In a standalone configuration, the WTRUs 102a, 102b, 102c may utilize one or more gNBs 180a, 180b, 180c as mobility anchor points. In a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using signals in unlicensed bands. In a non-standalone configuration, the WTRUs 102a, 102b, 102c may communicate / connect with a gNB 180a, 180b, 180c while communicating / connecting with another RAN, such as an eNode-B 160a, 160b, 160c. For example, the WTRUs 102a, 102b, 102c may implement a DC principle to communicate with one or more gNBs 180a, 180b, 180c and one or more eNode-Bs 160a, 160b, 160c substantially simultaneously. In a non-standalone configuration, the eNode-Bs 160a, 160b, 160c may act as a mobility anchor for the WTRUs 102a, 102b, 102c, and the gNBs 180a, 180b, 180c may provide additional coverage and / or throughput for serving the WTRUs 102a, 102b, 102c.

[0059] Each of the gNBs 180a, 180b, 180c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the UL and / or DL, support for network slicing, dual connectivity, interworking between NR and E-UTRA, routing of user plane data to User Plane Functions (UPFs) 184a, 184b, routing of control plane information to Access and Mobility Management Functions (AMFs) 182a, 182b, etc. As shown in FIG. 1D, the gNBs 180a, 180b, 180c may communicate with each other via an Xn interface.

[0060] 1D may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one Session Management Function (SMF) 183a, 183b, and possibly a Data Network (DN) 185a, 185b. Although each of the foregoing elements is shown as part of the CN 115, it will be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0061] The AMFs 182a, 182b may be connected to one or more gNBs 180a, 180b, 180c in the RAN 113 via an N2 interface and may function as control nodes. For example, the AMFs 182a, 182b may perform functions such as authenticating users of the WTRUs 102a, 102b, 102c, supporting network slicing (e.g., handling different PDU sessions with different requirements), selecting a particular SMF 183a, 183b, registering an area, and so on. , termination of NAS signaling, mobility management, etc. Network slicing may be used by the AMF 182a, 182b to customize the CN support for the WTRUs 102a, 102b, 102c based on the type of service being utilized by the WTRUs 102a, 102b, 102c. For example, different network slices may be established for different use cases, such as services relying on ultra-reliable low latency (URLLC) access, services relying on enhanced massive mobile broadband (eMBB) access, services with machine type communications (MTC) access, etc. The AMF 162 may provide a control plane function for switching between the RAN 113 and other RANs (not shown) that use other radio technologies, such as LTE, LTE-A, LTE-A Pro, and / or non-3GPP access technologies like WiFi.

[0062] The SMFs 183a, 183b may be connected to the AMFs 182a, 182b in the CN 115 via an N11 interface. The SMFs 183a, 183b may also be connected to the UPFs 184a, 184b in the CN 115 via an N4 interface. The SMFs 183a, 183b may select and control the UPFs 184a, 184b and configure the routing of traffic through the UPFs 184a, 184b. The SMFs 183a, 183b may perform other functions such as managing and assigning UE IP addresses, managing PDU sessions, controlling policy enforcement and QoS, providing downlink data notification, etc. The PDU session type may be IP-based, non-IP-based, Ethernet-based, etc.

[0063] The UPFs 184a, 184b may be connected to one or more gNBs 180a, 180b, 180c in the RAN 113 via an N3 interface, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices. The UPFs 184, 184b may perform other functions, such as routing and forwarding packets, enforcing user plane policy, supporting multi-homed PDU sessions, handling user plane QoS, buffering downlink packets, providing a mobility anchor, etc.

[0064] The CN 115 may facilitate communication with other networks. For example, the CN 115 may include or communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that serves as an interface between the CN 115 and the PSTN 108. Additionally, the CN 115 may provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers. In an embodiment, the WTRUs 102a, 102b, 102c may connect to local data networks (DNs) 185a, 185b via the UPFs 184a, 184b via an N3 interface to the UPFs 184a, 184b and an N6 interface between the UPFs 184a, 184b and the DNs 185a, 185b.

[0065] 1A-1D and the corresponding description thereof, one or more, or all of the functions described herein with respect to one or more of the WTRUs 102a-d, base stations 114a-b, eNode-Bs 160a-c, MME 162, SGW 164, PGW 166, gNBs 180a-c, AMFs 182a-ab, UPFs 184a-b, SMFs 183a-b, DNs 185a-b, and / or any other device(s) described herein may be performed by one or more emulation devices (not shown). The emulation devices may be one or more devices configured to emulate one or more, or all of the functions described herein. For example, For example, an emulation device may be used to test other devices and / or to simulate network and / or WTRU functionality.

[0066] The emulation device can be designed to implement one or more tests of other devices in a lab environment and / or an operator network environment. For example, one or more emulation devices can perform one or more or all functions while fully or partially implemented and / or deployed as part of a wired and / or wireless communication network to test other devices in the communication network. One or more emulation devices can perform one or more or all functions while temporarily implemented / deployed as part of a wired and / or wireless communication network. The emulation device can be directly coupled to another device for testing purposes and / or can perform testing using over-the-air wireless communication.

[0067] The one or more emulation devices may perform one or more functions, inclusive, while not implemented / deployed as part of a wired and / or wireless communication network. For example, the emulation devices may be utilized in test scenarios in a test lab and / or in an undeployed (e.g., test) wired and / or wireless communication network to implement testing of one or more components. The one or more emulation devices may be test equipment. Direct RF coupling and / or wireless communication via RF circuitry (which may include, for example, one or more antennas) may be used by the emulation devices to transmit and / or receive data.

[0068] As described herein, a WTRU may run one or more V2X applications. In this specification, a source WTRU is interchangeably referred to as a requestor WTRU, and a target WTRU is interchangeably referred to as a destination WTRU or a peer WTRU.

[0069] In an example V2X architecture, a V2X Application Server (AS) may be located in the network and interface with the V2X application installed in the WTRU (i.e., the V2X device in this context). A V2X Control Function (CF) may handle authorization and provisioning of the V2X device (i.e., configuration of V2X policies and parameters for the WTRU). The V2X Control Function (CF) may be located in the 5G CN and may be considered to be part of a service-based architecture. V2X inter-WTRU communication may be based on two operation modes. In the first mode, V2X inter-WTRU communication may take place over the LTE-Uu interface. In the second mode, V2X inter-WTRU communication may take place over the PC5 (V2X Sidelink or Proximity Services (ProSe)) interface.

[0070] V2X communication over the PC5 reference point is a type of ProSe direct communication. One-to-one ProSe direct communication can be achieved by establishing a secure Layer 2 (L2) link over PC5 between two WTRUs. The initiating WTRU attempting to establish a link must have the L2 ID (ID) of both itself and the peer (target) WTRU. The L2 ID of the target WTRU can be pre-configured in the initiating WTRU or obtained via ProSe direct discovery. The initiating WTRU can initiate the direct link setup by generating a PC5 signaling message (e.g., a DIRECT_COMMUNICATION_REQUEST message). The message may include 1) a user information set, 2) an IP address configuration information element (IE), 3) a link-local IPv6 address IE, and 4) a maximum inactivity period IE. When the target WTRU receives a message (e.g., a DIRECT_COMMUNICATION_REQUEST message) from the initiating WTRU, the target WTRU can send the L2ID to the initiating WTRU and the L2ID to the target WTRU. The pair of D may be stored and associated with the direct link in the context. After the link authentication procedure is completed and the security association is successfully established, the target WTRU may send a message (e.g., a DIRECT_COMMUNICATION_ACCEPT message) to the initiating WTRU. After receiving a PC5 signaling message (e.g., a DIRECT_COMMUNICATION_ACCEPT message) from the target WTRU, the initiating WTRU may use the established link for all one-to-one communications with the target WTRU.

[0071] Each WTRU may have an L2 ID for unicast communications, which is included in the source L2 ID field of all frames it transmits on the L2 link and in the destination L2 ID of all frames it receives on the L2 link.

[0072] The PC5 signaling protocol supports a keep-alive feature that can be used to detect if the WTRU is not in ProSe communication range, e.g., the implicit L2 link release can proceed. The requesting WTRU can initiate the keep-alive procedure, e.g., when (1) a request from higher layers to check the viability of the direct link is received or (2) the keep-alive timer for the direct link expires.

[0073] The source L2 ID may be changed and randomized over time for security reasons, e.g., to avoid tracking and / or identification of the source WTRU (e.g., vehicle) by any other WTRU (e.g., other vehicles) beyond a certain short period of time required by the application. This applies to both the WTRU and the identifiers associated with the session, i.e., both the source and the target.

[0074] In some implementations, the security association and session identifier ( KD-sess I D) is provided. During link establishment, a security association may be created between peer WTRUs to secure the link (i.e., to facilitate confidentiality and integrity protection). Each peer WTRU maintains a security context locally that contains the keys to encrypt / decrypt messages and ensure message integrity. This security context is associated with this particular peer-to-peer link. A security association identifier ( KD-sess (which may be referred to as a Message ID) A session identifier (i.e., a session identifier for a peer WTRU) may be used by each peer WTRU to identify and obtain a security context and / or keys when a message is received (e.g., to check the integrity of the message and / or to decrypt the message) or when a message needs to be sent (e.g., to encrypt the message and / or to protect its integrity). KD-sessID) for each peer It is created by concatenating the identifier components from: KD-sess ID The most significant byte (MSB) (i.e., the most significant 8 bits) of is from the initiating WTRU, and D-sess The least significant byte (LSB) (i.e., the least significant 8 bits) of the ID is from the peer WTRU. Each WTRU: KD-sess That part of the ID (i.e., the MSB or L SB) to obtain the security context associated with the link.

[0075] 2 illustrates an example Packet Data Convergence Protocol (PDCP) header for one-to-one communication 200. As shown in FIG. 2, a session identifier 201 (i.e., KD-sess The count ID represents the number of packets exchanged since the security context was established. The PDCP header, along with a ciphertext 202, is transmitted with each packet as part of the PDCP header. The PDCP also includes a payload portion 203, which is optionally encrypted, and an optional Message Authentication Code (MAC) portion 204.

[0076] Enhanced V2X (eV2X) can support unicast / multicast over PC5 for eV2X communications. In addition to the broadcast mechanism, eV2X can support new interactive distribution mechanisms to handle high data rate data sharing between vehicles, e.g., using unicast and / or multicast. Such mechanisms may utilize long running sessions using the same source L2ID. This may lead to privacy issues if the source L2IDs are tracked and linked. Such privacy issues affect both peers, i.e., source WTRU and target WTRU.

[0077] Therefore, it may be desirable to change the source L2ID while a session is ongoing (e.g., periodically or randomly). However, if the source L2ID is changed at the source WTRU, the peer WTRU may need to be notified since ongoing sessions are identified by the source L2ID. Current ProSe mechanisms do not support changing the source L2ID of an ongoing session. Furthermore, changing the L2ID may cause other problems. For example, a WTRU that has multiple sessions and uses the same L2ID may need to update all sessions / peers simultaneously (or within a defined time period, e.g., within a short time period). It may also be necessary for the WTRU to update the L2ID for each session. For each session, the WTRU may need to continue receiving traffic on the old L2ID until the change in the L2ID is confirmed by the peer WTRU. Such a requirement may generate or require inefficient procedures, e.g., multiple message exchanges since all WTRUs in this example must periodically change their L2IDs.

[0078] Privacy of the Security Context ID may also need to be addressed. In some implementations, the same KD-sess ID is If used, the security context ID sent in the PDCP header ( KD-sess ID) may be used by an eavesdropper to indirectly detect that an old L2ID (e.g., source or destination L2ID) has been changed to a new L2ID.

[0079] For privacy or other communications security purposes, it may be desirable to prevent an eavesdropper from linking the old and new L2IDs while the source WTRU is communicating the change in L2ID to a peer WTRU.

[0080] While the new procedures are generally described herein with reference to source WTRU and source IDs, it should be noted that the source WTRU and target WTRU involved in the communication can assume the role of source and / or target, respectively, depending on the peers through which a particular exchange is being carried out. Various methods, systems, and devices are described herein that facilitate changing the source and target L2 IDs associated with an ongoing session. The session may be a unicast or multicast session that is used for a particular period of time that is long enough to tolerate potential tracking threats. This period may be determined arbitrarily, empirically, or in any suitable manner. The period may vary depending on the application that uses it, e.g., the application that transmits the time information above the threshold. It should be noted that V2X, as used in this document, serves as an example of direct WTRU-to-WTRU communication (e.g., utilizing a ProSe PC5 interface). It may also be applied to other types of WTRU-to-WTRU communication (e.g., drones).

[0081] For example, the WTRU may be provisioned with a new interval (e.g., privacy timer) that may be set to the lifetime of its L2 ID for unicast communication and may include privacy protection parameters. Such parameters may also be the output of a function (e.g., a pseudorandom function). According to this interval, if the session is still ongoing, ,The WTRU's L2 ID must be changed (and randomized) within a,specified interval. After the ID is changed, the timer,can be restarted to change the L2 ID again within a specified,period. This process can be repeated as long as the session,is ongoing.

[0082] As explained previously, a change in the L2ID of one or both WTRUs (i.e., source and / or target) may need to be communicated to other WTRUs participating in the communication. The WTRUs may also need to be aware of the value of the new L2ID value. Additionally, the source WTRU may need to communicate the security context and security context ID ( KD-sess ID) with the peer WTRU. Conversely, the source WTRU may update its L2ID during a procedure used to update the security context (such as a direct link rekey procedure). Because a session involves two WTRUs (i.e., source and target) and two L2IDs, both L2IDs may need to be changed simultaneously, and each WTRU may need to be informed when the other WTRU changes its L2ID. The new source and target L2IDs associated with an ongoing session may be changed independently, i.e., one after the other in the same procedure, or simultaneously.

[0083] In some examples, more than one event may trigger the regeneration and update of the L2 ID at the peer WTRU. For example, the regeneration and update of the L2 ID may be triggered by expiration of a timer, receipt of a new L2 ID value from the peer WTRU, an update of an associated application ID, a request from the peer WTRU, a change in communication context, or other events. Although the high-level view and example methods described below are detailed based on a privacy timer for example purposes, it is understood that any of the above triggers, or other suitable triggers, may apply.

[0084] In some examples, a "relay" WTRU may be used between the source WTRU and the target WTRU. This "relay" is not shown or described in the various figures and descriptions herein. However, the same procedures described in the following subsections may apply to communications involving a relay WTRU, with the relay being used only to forward messages (e.g., "transparently") between the source WTRU and the target WTRU.

[0085] As explained above, in some implementations, a WTRU with multiple sessions using the same L2ID needs to update all sessions / peers at the same time (or within a defined time, e.g., a short time). In some implementations, for each session, the WTRU needs to continue receiving traffic on the old L2ID until the change of the L2ID is confirmed by the peer WTRU. This can lead to inefficiencies in the L2ID change mechanism, e.g., potentially generating multiple message exchanges since all WTRUs must periodically change their L2IDs. Therefore, to simplify the L2ID update procedure and eliminate or reduce the impact on other sessions, it is disclosed herein that in some implementations, a WTRU implementing privacy support can use a different L2ID for each session. In other words, in such newly disclosed implementations, all unicast sessions with different peer WTRUs use different source L2IDs. Also, each session with the same peer WTRU can be associated with only one application. Also, multiple applications running on a source / target WTRU can all use separate sessions.

[0086] FIG. 3 is a sequence diagram illustrating a high level view of an example of a requestor / source WTRU 380 L2ID change, and optionally, a peer / destination / target WTRU 390 L2ID change. Schart 300, which may occur simultaneously.

[0087] In reference block 301 of FIG. 3, the WTRU is provisioned with privacy specific parameters, e.g., privacy timer value, seed value for generating L2ID, seed value for generating privacy timer, etc. A privacy policy is also provisioned and can be configured for a single WTRU or both WTRUs, e.g., privacy enable / disable, L2ID privacy only, L2ID+ KD-sess ID privacy etc. Methods that can be used as or for the provisioning information are shown. Such provisioning information may be provided by a V2X Control Function (CF), a V2X Application Server (AS), or the parameters may be pre-provisioned at the WTRU (e.g., at either the Mobile Equipment (ME) or Universal Integrated Circuit Card (UICC)). These parameters can be provisioned per WTRU (e.g., for use for all ProSe / V2X direct communications for a particular WTRU) or based on a per-V2X application ID (e.g., Intelligent Transportation System Application Identifier (ITS-AID) or Provider Service Identifier (PSID)) (e.g., for use for all ProSe / V2X direct communications for a particular V2X application). In reference block 302 of FIG. 3, PC5 communication is set up between a source WTRU and a peer WTRU (referred to as UE in FIG. 3). The peer WTRU may be provisioned with the privacy-specific parameters (as described above) of the source WTRU, for example, during session establishment (and vice versa). The privacy policy received at the peer WTRU may be compared with the provisioned policy of the peer WTRU, and the top matching privacy protection method may be selected. The source WTRU may be provisioned with the privacy-specific parameters of the peer WTRU (as described above), for example, during link establishment. Blocks 301 and 302 in Figure 3 represent the setup procedure for PC5 communication.

[0088] At blocks 303A and 303B of FIG. 3, a privacy timer is started at the source WTRU (and optionally the peer WTRU). At block 304 of FIG. 3, communication continues between the source L2ID#1 (and the peer L2ID#1) and KD-sess Use ID#1 In block 305A1, the source WTRU 380 may apply a selected privacy policy to the ongoing session (where the selected policy to be applied is the L2ID+ of both sides). KD-sess (We assume that identity privacy is enabled.) The source WTRU , generate or otherwise obtain a new source L2 ID (e.g., source L2 ID#2), e.g., from a higher layer, and a new part of the session ID (e.g., KD-sess I Get the MSB of D#2. KD-sess The new L2ID and new MSB of ID#2 are , used in this session and stored locally with the existing ID KD-sess Current ID It is associated with the source L2ID and the current MSB. At this point, it has the existing source L2ID (Source L2ID#1) and possibly the Session ID ( KD-sess ID#1) The source WTRU sends a new source L2ID in a new L2ID IE and possibly in new MSBs of the Session ID IE. KD-sess The new MSB of the ID (e.g., WTRU) or the peer WTRU itself regenerates a source L2 ID (e.g., using a method described herein) identical to the one obtained at the source WTRU. In the latter case, since no privacy messages are exchanged between the peer WTRUs, KD-sessNote that it may not be necessary to update the ID. In this state, the same procedure can be performed simultaneously on both WTRUs to change the L2 ID and possibly the Session ID in the same procedure. The privacy timer is just one example of a trigger for changing the L2 ID and Session ID. The L2 ID and Session ID can also be changed. It may also be generated and then communicated to other WTRUs, for example, when the WTRU receives a new source L2ID from a peer WTRU, when a higher layer or application layer triggers a privacy procedure, when the WTRU moves to a new geographical area, when the WTRU receives new privacy parameters and / or policies from a V2X Control Function (CF) or V2X Application Server (AS), or when the UE receives a request to trigger a privacy procedure from its peer, for example, as described herein.

[0089] In some implementations, if the V2X layer is triggered to change the L2 ID, e.g., timer, request from peer, etc., the V2X layer can inform / communicate to the upper layer about the impending change of ID, e.g., for synchronization purposes. The upper layer can respond with a new upper layer ID, which can be sent to the peer WTRU along with the new L2 ID. In some implementations, the interface between the V2X layer and the upper layer is extended to allow such information to be passed, e.g., by an indication from the V2X layer to the application and a response from the application to the V2X layer.

[0090] At blocks 306A and 306B, the new source (and optionally peer) L2 ID and Session ID are synchronized / communicated across layers on both WTRUs for PC5 communication. Such synchronization / communication is essentially communication between layers (e.g., components and / or instances and / or functions) of the V2X application portion, ensuring that all such components (hardware and / or software) that rely on the updated L2ID information, wherever located, are updated with the latest values. The higher layers may know which L2ID is being used and which AS layer will use the L2ID for PC5 communication. After the new source L2ID is synchronized / communicated, the new source L2ID (#2), and possibly the Session ID (#3), are synchronized / communicated across layers on both WTRUs for PC5 communication. KD-sess A new peer L2 ID#2 is used for the ongoing session. Once set, it is also used for ongoing sessions, as in block 306A1. In blocks 307A and 307B, the privacy timer is restarted in the source WTRU (and optionally in the peer WTRU).

[0091] Some approaches for updating the L2 ID and session ID associated with an ongoing session (e.g., block 305A1 shown and described with respect to FIG. 3) include the following and are further detailed herein.

[0092] In the new first method (Method 1), some examples include an exchange of a new L2 ID between the source WTRU and the target WTRU. Such examples may include modification of existing messages (such as ProSe keep-alive messages) to carry the new source L2 ID, e.g., to support parallel exchange of new source and peer L2 IDs. In a further extension of Method 1, referred to below as Method 3, KD-sess New MS of ID B and KD-sess Exchange of the LSBs of the IDs and the new L2 Such method 1-based examples and extensions may include, for example, to support parallel exchange of new source and peer L2 IDs, and / or KD-sess New MSB of ID and KD-sess To support the exchange of the LSBs of the ID with a new session ID, a procedure may be included to introduce a new privacy message and carry a new source L2 ID. In some examples, the WTRU may request its peer to change its L2 ID, which may be referred to as peer triggering. In some examples, an existing rekey message is modified to support the parallel exchange of a new source L2 ID and peer L2 ID.

[0093] The new second method (Method 2) involves generating a new L2ID for the peer in some instances. In such an example, a source seed may be provided to the target WTRU and a target seed may be provided to the source WTRU. Such an example may include modifying an existing message (e.g., a ProSe keep-alive message or a PC5 direct link establishment message) to configure the seed used to regenerate the L2 ID at the peer WTRU. Such an example may also include introducing a new privacy message to exchange the seed or seeds. In such an example, other PC5 signaling messages may be updated to carry the "seed".

[0094] In a new third method (Method 3), briefly described above, Method 1, also introduced above, can be extended with the exchange of a new Session ID to enhance privacy protection. In a new fourth method (Method 4), the existing rekeying procedure, which also generates a new Session ID, can be enhanced by the exchange of a new L2 ID between communicating WTRUs.

[0095] Some examples described herein include privacy parameter and / or policy provisioning at the source WTRU and the peer WTRU, for example, using a WTRU (or UE) Configuration Update (UCU) procedure and / or during setup of a PC5 link.

[0096] Some examples include provisioning of privacy parameters. For example, the provisioning and PC5 link setup procedures can be modified to support privacy procedures. In some examples, the WTRU (source and / or target) is provisioned with new privacy timer values ​​and other parameters as described using the same mechanisms used for eV2X provisioning, for example, via a Non-Access Stratum (NAS) Transparent Container, V3 interface, or UCU procedure with a V2X application server. A zero value configuration may disable the source L2ID regeneration procedure. If no provisioning is provided, default values ​​may be used.

[0097] The WTRU may also be provisioned with a new privacy policy that the WTRU uses to determine privacy related behavior. A privacy policy may be specified per V2X application (e.g., Intelligent Transportation System-AID (ITS-AID) or (Provider Service Identifier (PSID)). The privacy policy may specify, for example, the supported privacy protection methods (PPMs), which may be identified by configuration. For example, there may be the following values: PPM1 (disabled - no privacy processing), PPM2 (L2ID privacy using only method 1, single UE L2ID update), PPM3 (L2ID privacy using only method 1, L2ID update for both UEs), PPM4 (L2ID privacy using only method 2, L2ID update for both UEs), PPM5 (L2ID+Session ID privacy using method 3), PPM6 (L2ID+Session ID privacy using method 4), and / or other suitable values.

[0098] FIG. 4 is a sequence chart 400 illustrating an example of privacy parameter provisioning. In message 401, the V2X Control Function (V2X) or Policy Control Function (PCF) 440 forwards eV2X provisioning parameters to the AMF 430 in a policy container to configure the WTRU (shown as UE 410 in FIG. 4). New eV2X specific parameters for privacy support (e.g., privacy timer, seed value for generating L2ID, seed value for generating privacy timer, etc.) are added to the policy container along with the existing parameters. A privacy policy may also be specified. In message 402, the AMF forwards the WTRU policy container to the WTRU using the (R)AN 420. This forwarding is performed when the AMF It may be considered "transparent" since it forwards the WTRU policy container to the WTRU without reading or modifying it. The eV2X parameters are stored locally on the UE in block 402A. In message 403, the WTRU sends the result of the WTRU policy delivery to the AMF. In message 404, the AMF notifies the V2X CF or PCF if registered to notify the receipt of the WTRU policy container.

[0099] Examples of privacy procedures include a direct link setup procedure updated with privacy parameters. In some examples, the direct link setup procedure is used to indicate to the other WTRU that a change of L2ID is required in the current session during an ongoing PC5 session. This can be accomplished, for example, by including a new indication in the direct communication request message and / or by passing a privacy timer value from one WTRU to the other WTRU. For this purpose, a new Privacy Timer IE can be introduced that contains the privacy timer value. A new Privacy Indication IE may also be introduced and may be set to a provisioned value, e.g., PPM2, PPM3, PPM4 (as described above). The selection of the PPM may be negotiated between the two WTRUs during link setup. For example, the highest privacy protection that both support can be selected. For example, PPM2, PPM3, and PPM4 may be supported by the originating WTRU, while only PPM2 and PPM3 are supported by the peer WTRU. Thus, PPM3 (e.g., L2ID privacy using only method 1, both WTRUs L2ID updated) is selected for this particular session. The selected PPM determines the WTRU's behavior for the lifetime of the session, i.e., whether privacy protection is applied, which method is used, whether both peers update their L2IDs, whether the session ID is updated, etc. A given WTRU may select a different PPM for each session based on the provisioned privacy policy and the negotiation process described above. For example, a WTRU may set up two sessions with another WTRU and select a different PPM for each session (e.g., each session is associated with a different V2X application, each application has a specific privacy policy). The peer WTRU may reject the link setup if it does not find an acceptable (e.g., common) PPM based on the provisioned values ​​and the values ​​proposed by the originating WTRU.

[0100] FIG. 5 is a sequence chart 500 illustrating an example of such a direct link setup procedure. Message 501 is a direct communication request sent from a requester or source WTRU 510 to a destination or target or peer WTRU 520 and may include a privacy indication, a source WTRU privacy timer, and / or a supported privacy policy. Message 502 is a direct communication receive sent in response to a request message from a destination or target or peer WTRU 520 to a requester or source WTRU 510, which confirms the privacy indication, the source WTRU privacy timer, and / or a supported privacy policy sent in the request message. In some examples, the privacy timer value is passed to other WTRUs to notify them in advance, e.g., periodically, that the L2 ID will change during the lifetime of the session. A WTRU receiving a privacy timer setting from a peer can expect the change within the time specified by the privacy timer value. If the change does not occur within this period, the receiving WTRU can trigger a replacement of this ID, e.g., using the privacy procedures shown and described with respect to FIG. 9.

[0101] Next, an example of the above referenced method 1 is described. Some examples of method 1 include the exchange of a new L2 identifier. In some examples, the WTRU exchanges the new L2 ID one after the other, either during the same procedure or independently. The privacy timer value is set using this procedure. It can also be updated.

[0102] In some examples, the ProSe direct link keep-alive procedure is updated with a new source L2ID. The ProSe direct link keep-alive procedure can be reused to change the L2ID associated with an ongoing session. Also, a new L2ID IE can be introduced. The existing keep-alive message may include a new L2ID IE, which may be set to the new source / target L2ID value. A new privacy timer value may be provisioned on the WTRU (e.g., as shown and described with respect to FIG. 4) and can be used as a new trigger to (a) generate a new L2ID and (b) start the keep-alive procedure, which may include the newly acquired L2ID IE.

[0103] FIG. 6 is a sequence chart 600 illustrating an example of an exchange of a new L2 identifier on a requestor or source WTRU 610 using an updated direct link keep-alive procedure, triggered by the expiration of a privacy timer, to update the source L2 ID of an existing session on a peer WTRU 620. FIG. 6 represents an example of Method 1, where only the source L2 ID is changed. Note that the keep-alive procedures and messages are used for convenience to illustrate and explain the exchange of a new source L2 ID. However, flowever, other PC5 signaling messages and procedures can be modified in a similar manner and used to achieve the same results. In block 601, V2X parameters are provisioned in the WTRUs 610 and 620 and the session is set up. In block 602, the source WTRU 610 runs a privacy timer using the provisioned values. In block 603, communication is ongoing using source L2 ID#1 (and peer L2 ID). At block 604, the privacy timer expires in the source WTRU 610 and the source L2 ID needs to be updated. At block 604A, a new source L2 ID is generated (e.g., Source L2ID#2). At block 604B, the source WTRU initiates a keep-alive procedure to send the new ID to the peer WTRU. The source WTRU sends a keep-alive message 630 to the peer WTRU containing the new source L2 ID in a new IE (e.g., Source_L2J DJ E). The current source L2 ID continues to be used because it is the ID associated with the session at this point and is the ID the peer knows / expects to be used. A new privacy timer value can also be set in the peer WTRU. The peer WTRU receives the new source L2 ID associated with the session and stores it locally. Both L2 IDs (old and new) can be stored locally in case a message using the old ID has been forwarded during the ID change procedure.The peer WTRU stops the keep-alive timer at block 640 and sends back a keep-alive acknowledgement message 650 with the new source L2ID IE (e.g., Source_L2JDJ E) set to the same value received in the keep-alive message. The previous L2ID continues to be used as the destination ID for this message. The old source L2ID may be deleted from local memory after receiving a message using the new L2ID or, for example, after a grace period. At step 4c, the keep-alive timer is restarted on both sides. At blocks 605A and 605B, the new source L2ID is synchronized / communicated across layers on both WTRUs for PC5 communications (e.g., when the higher layers know which WTRU ID is used and the AS layer uses the L2ID for PC5 communications). At block 606, the source WTRU restarts the privacy timer since the source L2ID needs to be changed periodically. In block 607, the new source L2 ID is used from this point onwards from both sides.

[0104] In some cases, both WTRUs update the L2 ID in the same procedure. In such cases, The target WTRU may decide to update its L2 ID at the same time as the source WTRU, for example, when it receives a keep-alive message. Figure 7 is a sequence chart 700 illustrating an example of this method 1 exchange in which both L2 IDs are changed in both the requestor / source WTRU 710 and the peer / destination WTRU 720. The exchange in Figure 7 is similar to that previously described with respect to Figure 6, with some modifications as shown in Figure 7.

[0105] For example, blocks 701 and 703 are the same as in FIG. 6. Blocks 702A and 702B show that the privacy timer is written in both WTRUs. In blocks 704A and 704B, the privacy timer expires in the source and peer WTRUs and the L2ID needs to be updated. In blocks 704A1 and 704B1, a new L2ID is generated on both WTRUs (e.g., source L2ID#2, peer L2ID#2). In block 704A2, the source WTRU initiates a keep-alive procedure to send its new ID to the peer WTRU. The source WTRU sends a keep-alive message 730 with its new L2ID in a new IE (e.g., Source_L2JDJ E). The current source L2ID continues to be used because it is the ID associated with the session at this point and is the ID the peer knows / expects to be used. A new privacy timer value can also be set in the source / peer WTRU. The peer WTRU receives the new source L2ID and stores it locally. Both L2IDs (old and new) can be stored locally in case a message using the old ID has been forwarded during the ID change procedure. Since the keep-alive message was received, the peer WTRU stops the keep-alive timer in block 740. The peer WTRU sends back a response message 750 containing the new source L2ID IE set to the same value received in the keep-alive message (i.e., source L2ID#1) and another new IE (e.g., target_L2JDJE) contains the new ID. The old L2ID continues to be used as the source / destination ID for this message. After receiving the response message, the source WTRU responds with an acknowledgement message 760 containing the new target L2ID IE. However, the target's old L2ID continues to be used as the destination ID for this message.In blocks 705A and 705B, the new source / peer L2 ID is synchronized / communicated across layers on both WTRUs for PC5 communication (e.g., when the higher layers know which WTRU ID to use and the AS layer uses the L2 ID for PC5 communication). In blocks 706A and 706B, both WTRUs restart their privacy timers since the source L2 ID needs to be changed periodically. The keep-alive timer is also restarted. In block 707, the new L2 ID is used from both sides from this point on. In some examples, a new ProSe direct link privacy procedure is introduced. In such examples, a new dedicated direct link privacy procedure is used to change the source L2 ID associated with the session. The new privacy procedure uses its own privacy timer and privacy messages (e.g., Privacy_Request, Privacy_Response, Privacy_Trigger). The privacy procedure can be initiated from the source WTRU or the peer WTRU. The procedure can be used to update the L2 ID of a single WTRU or the L2 ID of both WTRUs.

[0106] In some examples, the source WTRU initiates a privacy procedure for a single L2 ID change. Figure 8 is a sequence chart 800 illustrating an example of such a privacy procedure. In this example, a privacy timer value is provisioned in the source WTRU. Upon expiration of the timer, the WTRU obtains a new L2 ID and updates the peer WTRU with the new L2 ID. Figure 8 illustrates an example of the newly defined privacy procedure using direct link privacy communication between two WTRUs corresponding to one option of Method 1.

[0107] In block 801, V2X parameters are provisioned in the WTRU and a session is set up. In block 802, the source WTRU starts a privacy timer using the provisioned values. In block 803, communication is ongoing between the source WTRU and the peer WTRU. In block 804, the privacy timer expires in the source WTRU. In block 804A1, the source WTRU generates a new source L2ID (e.g., source L2ID#2). In block 804A2, the privacy procedure is initiated. The source WTRU sends a Privacy_Request message 830 containing the new source L2ID IE. A new privacy timer value IE may also be specified if the timer value needs to be changed. The peer WTRU receives and locally stores the peer's new source L2ID. The peer WTRU sends back a Privacy_Response message 840 containing the new source L2ID IE set to the same value received in the Privacy_Request message 830. At blocks 805A and 805B, the new source L2 ID is synchronized / communicated across layers on both WTRUs for PC5 communications (e.g., where the higher layers know which WTRU ID is used and the AS layer uses the L2 ID for PC5 communications). At block 806, the source WTRU restarts the privacy timer. At block 807, the new source L2 ID may be used from this point on.

[0108] In some examples, both L2 IDs are updated in the same procedure. Figure 9 is a sequence chart 900 illustrating an example of such a procedure. In this example, the peer WTRU updates its L2 ID at the same time as the source WTRU, and the exchange of new L2 IDs is performed in the same procedure. Figure 9 illustrates an example of a newly defined privacy procedure using direct link privacy communication between two WTRUs, corresponding to another option of Method 1, where both WTRUs update their L2 IDs in the same procedure.

[0109] At block 901, V2X parameters are provisioned in the WTRU and a session is set up. At blocks 902A and 902B, the source WTRU 910 and the peer WTRU 920 start a privacy timer using the provisioned values. At block 903, communication is ongoing between the source WTRU and the peer WTRU. At blocks 904A and 904B, the privacy timer expires at the source WTRU and possibly the peer WTRU. At block 904A1, the source WTRU generates a new source L2ID (e.g., source L2ID#2). The source WTRU sends a Privacy_Request message 930 including the new source L2ID IE and optionally a new privacy timer IE if the timer value needs to be updated. The peer WTRU receives the new source L2ID of the source WTRU and stores it locally. At block 904B1, the peer WTRU generates a new peer L2ID (e.g., peer L2ID#2) (a) when the privacy timer expires (block 904B), or optionally (b) upon receipt of a privacy request message 930. The peer WTRU sends back a Privacy_Response message 940 containing the new source L2ID IE set to the same value received in the privacy request message and also containing the new peer L2ID. Optionally, a new privacy timer IE may be included if the peer timer value needs to be updated. The source WTRU receives the privacy response message 940 containing the new peer WTRU L2ID IE, stores this new ID locally, and responds with a privacy confirm message 950 containing the new peer L2ID. At blocks 905A and 905B, the new L2ID is generated (e.g., when higher layers determine which WTRU The AS layer knows which L2 ID is used and is synchronized / communicated across layers on both WTRUs for PC5 communication (in case the AS layer uses L2 ID for PC5 communication). In blocks 906A and 906B, each WTRU restarts its privacy timer. In block 907, from this point on, the new L2 ID is used.

[0110] In some examples, the WTRU triggers the privacy procedure on the peer side. For example, a WTRU may request its peer to change its L2ID (e.g., the peer WTRU requests the source WTRU to change its L2ID, i.e., source L2ID). A source WTRU receiving such a request may trigger an L2ID update procedure. In this case, the source WTRU obtains a new L2ID and updates the peer WTRU with the new L2ID. The peer WTRU, configured with a source WTRU privacy timer value during the link setup procedure, may update the source WTRU privacy timer value when, for example, (a) it receives a trigger locally (e.g., from a higher layer) or determines that it needs to change the source L2ID (e.g., due to an appropriate reason or additional trigger), or (b) the peer WTRU wants to update its L2ID at the same time as the source WTRU. It may be decided to trigger a change of the L2ID.

[0111] FIG. 10 is a sequence chart 1000 illustrating an example of the steps of a method 1 in which a peer WTRU triggers an L2 ID change procedure. In block 1001, a session is set up and communication is ongoing between a source WTRU 1010 and a peer WTRU 1020. In blocks 1002A and 1002B, both WTRUs may start a privacy timer. In block 1003, communication is ongoing between the source WTRU and the peer WTRU. In block 1004, the peer WTRU determines that the source WTRU should change its L2 ID, and the peer L2 ID may need to be changed as well. The peer WTRU sends a new Privacy_Trigger message 1030 to the source WTRU. The peer WTRU may generate a new L2 ID if the L2 ID needs to be updated in optional block 1004B1. Otherwise, the source WTRU receiving this trigger message 1030 stops its privacy timer in block 1005. At block 1005A1, a new source L2 ID (e.g., source L2ID#2) is generated. At block 1005A2, the source WTRU initiates privacy procedures to send its new ID to the peer WTRU. Direct privacy messages are exchanged at block 1006. Alternatively, the source WTRU may send the new source L2 ID to the peer WTRU using a keep-alive procedure, e.g., as shown and described with respect to FIG. 6. If only the source L2 ID is changed, the procedures shown and described with respect to FIGS. 6 and 8 may be used. If both L2 IDs are changed, the procedures shown and described with respect to FIGS. 7 and 9 may be used. At blocks 1007A and 1007B, the new L2 ID is synchronized / communicated across layers on both WTRUs for PC5 communications (e.g., where the higher layers know which WTRU ID is used and the AS layer uses the L2 ID for PC5 communications). At blocks 1008A and 1008B, the privacy timer is restarted in both WTRUs.At block 1009, communication is ongoing using the new source L2ID#2 and, if changed, the new peer L2ID#2.

[0112] Examples of Method 2 L2ID changes include the generation of peer L2IDs at the source and target WTRUs. In some Method 2 examples, the peer L2IDs are regenerated from the source WTRU itself instead of exchanging new IDs via messages. In such examples, during the V2X parameter provisioning phase, each WTRU may be provisioned with a list of secret parameters and seeds along with other required V2X parameters. The seeds can be used to regenerate the WTRU's L2ID.

[0113] After a session is established between the source WTRU and the peer WTRU, and After the privacy keys have been exchanged and communications secured, the source WTRU and the peer WTRU may exchange their privacy timer values ​​and seeds. Thus, the WTRU is configured with the peer's (a) privacy timer value and (b) the seed to be used for new L2 ID regeneration.

[0114] The WTRU may use the same seed or a different seed value (e.g., provisioned for generating the timer) to generate the privacy timer. If a different seed is used to generate the timer value, such seed values ​​may also be exchanged between WTRUs. The timer seed value may facilitate randomization of the timer value for changing the privacy timer.

[0115] In some examples, a list of seeds with potentially corresponding timers may be configured on both sides and exchanged during the same procedure. This described procedure may reduce or limit over-the-air message exchange. The seed used to generate the new L2ID of the target WTRU may be continuously selected from the list of seeds provided after the privacy timer expires. The WTRU starts the peer_privacy_timer and when the timer expires, it regenerates the peer L2ID based on the configured seed. At the same time, the peer WTRU also regenerates its own L2ID using the same seed and the same value is obtained. The generation of the new L2ID of the target WTRU may be done periodically. The seed and timer values ​​may be configured in the peer WTRU using an updated keep-alive mechanism, other updated PC5 signaling messages, or new messages.

[0116] FIG. 11 is a sequence chart 1100 illustrating an example method 2 procedure in which a source WTRU configures a peer WTRU to be able to regenerate a source L2ID after a timer expires. Such a mechanism can be used from the destination WTRU to the source WTRU. In FIG. 11, the source L2ID is regenerated on the source WTRU and the peer WTRU. In block 1101, a session is set up between the source WTRU and the peer WTRU. In block 1102, communication between the source WTRU and the peer WTRU is ongoing. At this point, "source L2ID#1" is used. In block 1102A, a privacy timer is started in the source WTRU. In block 1103, a privacy timer and seed are sent to the peer WTRU (e.g., using either an updated keep-alive mechanism or a new message). The timer may indicate, for example, a duration of 15 minutes and a specific start time. In this example, the timer expires every 15 minutes past the specified start time. This can cause both timers to expire at the same time, even if they were not started at the same time. In block 1103A, the peer WTRU saves the source WTRU privacy timer value and seed, and starts the source WTRU privacy timer. For example, the procedures used to exchange information as shown and described with respect to Figures 6 and 8 can be used here, but in this case (new IE for seed) the privacy timer + seed is forwarded. In blocks 1104A and 1104B, after the timer expires, the source WTRU generates a new L2ID using the seed shared with its peer. In blocks 1104A1 and 1104B1, on the target WTRU, the timers have expired at the same time on the source WTRU. The target WTRU regenerates a new source WTRU L2ID using the seed value received from the source WTRU. The same value of the source L2ID is obtained in both WTRUs.At blocks 1105A and 1105B, the new source L2 ID is synchronized / communicated across layers on both WTRUs for PC5 communications (e.g., where the higher layers know which WTRU ID is used and the AS layer uses the L2 ID for PC5 communications). At blocks 1106A and 1106B, the privacy timer is restarted in both WTRUs. At block 1107, communication is ongoing between the source WTRU and the peer WTRU based on the newly formed source L2ID#2.

[0117] In some examples, the privacy timer value and seed may be exchanged using an updated keep-alive mechanism (e.g., as shown and described with respect to FIG. 6) or a new message (e.g., as shown and described with respect to FIG. 8). The timer value and seed may be updated constantly and / or periodically.

[0118] FIG. 12 is a sequence chart 1200 showing (A) a WTRU 1210 configuring its privacy timer value and seed on a peer WTRU 1220, and (B) both WTRUs exchanging those configurations. FIG. 12 illustrates a Method 2 exchange of privacy timer values ​​and seeds. Sequence A is an example of a message exchange in which the requestor / originator WTRU sends privacy timer and seed values ​​for each WTRU. In Sequence A, in message 1225, the WTRU 1210 sends a direct communication keep-alive, direct privacy request, or other message containing relevant information for forwarding the WTRU 1210 privacy timer and seed values ​​to the peer WTRU 1220. Upon receipt, the peer WTRU 1220 sends a response message 1230, which may be an acknowledgement of the received request message 1225. The acknowledgement message 1230 may include the originator WTRU privacy timer value and the originator seed value, among other possible message content. Sequence B may be an alternative to Sequence A. Sequence B is an example of a message exchange in which both WTRUs exchange their respective privacy timers and seed values. In sequence B, in message 1235, the WTRU 1210 sends a direct communication keep-alive, a direct privacy request, or other message containing relevant information for forwarding the WTRU 1210 privacy timer and seed value to the peer WTRU 1220. Upon receipt, the peer WTRU 1220 sends a response message 1240, which may be a response to the received request message 1235. The response message 1240 may include the source WTRU privacy timer value and source seed value, as well as the peer privacy timer and peer seed value, among other possible message content. After receiving the response message 1240, the source WTRU 1210 may send message 1245, which may be a direct communication keep-alive confirmation, a direct privacy confirmation, or other message containing relevant information for returning the peer WTRU 1220 privacy timer and seed value to the peer WTRU 1220. The above exchange examples A and B may establish the configuration of the WTRU, as in block 1103 of FIG.

[0119] Example method 3 may extend the exchange of a new L2 identifier with the exchange of a new session ID. In one example, method 3 extends method 1 with the exchange of a new session ID. For example, as described above, the WTRU may exchange a new session ID during the L2ID change procedure independently (i.e., one after the other) or simultaneously during the same procedure. Furthermore, the WTRU may be configured to update its security context identifier (e.g., session identifier) ​​simultaneously with its L2ID, e.g., for privacy reasons. To facilitate this, the exchange of a new L2 identifier described above may include, in addition to the source and destination L2IDs, KD-sess Allowing for MSB / LSB swapping of ID provides additional privacy It is extended with sea protection.

[0120] In a first scenario, a privacy timer may be running in the initiating / requesting / source WTRU. When the privacy timer expires or upon receiving a trigger from a peer WTRU, the initiating / requesting / source WTRU fetches the security context associated with the session (e.g., as described above for a ProSe direct link keep-alive procedure updated with a new source L2ID or if the source WTRU initiates a privacy procedure with a single L2ID change) and updates the L2ID. In addition to regenerating the L2ID, the WTRU also generates a new session identifier (i.e. KD-sess This new session ID is , may be sent to the peer WTRU along with the new L2 ID. Note that the communication is already protected, i.e., the exchanged L2 ID and session ID are encrypted and integrity protected. The new identifiers will be used upon successful completion of the procedure. Note that the contents of the security context itself do not change, i.e., the keys and other parameters (e.g., counters) stored in the security context remain the same, and only the session identifiers used to locate the security context locally at the initiating / requestor / source WTRU and peer / destination WTRU (i.e., each peer WTRU) are updated.

[0121] In the second scenario, both WTRUs update the IDs in the same procedure, i.e., both L2 IDs are updated in the same procedure and both WTRUs change part of the session identifier at the same time during the same privacy procedure. In this case, both WTRUs generate new parts of the session ID (MSBs and LSBs) and exchange them with the new L2 ID. This is shown in Figure 13 using a direct privacy message. Figure 13 is a message sequence chart 1300 showing the case where both WTRUs exchange new parts of the session ID using the privacy procedure.

[0122] In the example of FIG. 13, communication is ongoing between a source WTRU 1310 and a peer WTRU 1320 in block 1301, with the source WTRU using L2ID#1 and the peer WTRU using its own L2ID#1. KD-sess ID#1) A separate security association is established between the WTRUs. That is, each WTRU locally stores a security context that contains the security parameters (e.g., encryption keys) required to protect the communications. All information exchanged between the peers is encrypted and integrity protected. The initiating WTRU KD-sess Use the MSB of the ID to The peer WTRU identifies the security context on its side. KD-sessUse the LSB of the ID do.

[0123] At block 1302, a privacy timer expires at the source WTRU. The source WTRU generates a new source L2 ID (e.g., source L2 ID#2) at block 1302A, and the source WTRU generates a new source L2 ID (e.g., source L2 ID#2) at block 1302B. KD-sess ID New MSB (e.g. KD-sess The source WTRU generates the Priv acy_Request message 1303 or another PC5 signaling message (e.g., with new source L2ID IE and KD-sess P containing the new MSB of the ID IE C5 Link Update message) and optionally a new Privacy Timer IE.

[0124] The peer WTRU sends the KD-sess New source L2ID and new ID In block 1304A, the peer WTRU generates a new peer L2 ID (e.g., peer L2 ID#2). In block 1304B, the peer WTRU generates a new peer L2 ID (e.g., peer L2 ID#3). KD-sess The new LSB of the ID (i.e. KD-sess The peer WTRU generates the newly generated identifier (the LSB of ID#2) at block 1304C. The peer WTRU stores the newly generated identifier locally. The security context is KD-sess Updated locally with ID#2.

[0125] The peer WTRU sends back (to the source WTRU) a Privacy_Response message 1305 or another PC5 signaling message (such as a PC5 Link Update Response message) with Privacy_Response set to the same value as received in the Privacy Request message. KD-sess The new source L2ID IE and the new source MSB of the ID IE are included. R,KD-sess Also includes new peer L2ID IE and new peer LSB in ID IE In another embodiment, the peer WTRU may include a source WTRU that is expected to obtain them locally based on the current session context. KD-sess ID IE's new For example, the source WTRU does not send back the new source L2ID IE and new source MSB when it generates KD-sess Security identified by the current source MSB of the ID In block 1306, the source WTRU that receives the privacy response message 1305 can store the new peer L2ID IE and KD-sess Include the new peer LSB in the ID IE, store these new IDs locally, and update the new peer L2 ID and KD-sess Privacy confirmation message 13 containing the new LSB of the ID 07. At block 1308, from this point on, the new L2 ID and KD-sess The ID (MSB and LSB) is used.

[0126] In an example of method 4, the existing rekey procedure can be augmented with the exchange of a new L2 ID. In one example, method 4, the existing rekey procedure can be augmented with the exchange of a new L2 ID between the communicating WTRUs. The existing rekey procedure is used to update the security context of an ongoing session. In this case, all parameters are updated. For example, keys are regenerated, counters are reset, and a new session ID is also generated.

[0127] As an alternative to the various approaches described herein, this approach uses the existing rekey procedure (e.g., as described in 3GPP TS 33.303 6.5.5.3) and enhances it to allow for exchange of new source and destination L2 IDs between peer WTRUs along with a new session ID. As with the other approaches discussed herein, a privacy timer can be used to trigger this enhanced rekey procedure. Other triggers may also exist (e.g., from higher layers, a request from the peer WTRU, before the counter for the current link is repeated with the current key, etc.).

[0128] Note that the rekey procedure may imply changing the complete Session ID, i.e., MSB and LSB parts, and can be performed using an already established session. Thus, all messages exchanged between the peers are encrypted and integrity protected. However, changing the L2ID can be performed only in a single WTRU or in both WTRUs, if desired.

[0129] FIG. 14 is a message sequence chart 1400 illustrating the exchange of a new L2 ID using an enhanced rekey procedure. FIG. 14 provides an example use of method 4 to provide for the exchange of L2 IDs of both the source WTRU and the peer WTRU in the context of a rekey procedure. At block 1401, communication is ongoing between the source WTRU and the peer WTRU. The source WTRU 1410 is using L2 ID#1 and the peer WTRU 1420 is using its own L2 ID#1. The session ID ( KD-sess ID#1) A security association is established between the source WTRU and the peer WTRU to secure the communication (e.g., each WTRU locally stores a security context including the necessary security parameters (e.g., encryption keys)).

[0130] At block 1402, a privacy or rekey timer expires at the source WTRU (or another trigger occurs, e.g., from a higher layer). The source WTRU triggers a rekey procedure enhanced with an L2ID update exchange. At block 1402A, the source WTRU generates a new source L2ID (e.g., source L2ID#2). At block 1402B, the source WTRU: KD-sess ID New The new MSB (i.e. KD-sess The source WTRU generates the new new source L2ID IE and new MSB of the KD-sess ID, and optionally a new 14. The UE sends a DIRECT_REKEYING_REQUEST message 1403 containing the new privacy timer IE. The existing security context and L2IDs, i.e., the old source / destination L2IDs and the existing KD-sess ID, continue to be used for sending this message.

[0131] The peer WTRU transmits via message 1403 the new source L2 ID and KD-sess Receive the new MSBs of the ID and store them locally along with the previous value At block 1404A, the peer WTRU generates a new peer L2 ID (e.g., peer L2 ID#2). At block 1404B, the peer WTRU: KD-sess The WTRU generates a new LSB of the ID (i.e., the LSB of KD-sessID#2). In block 1404C, the WTRU stores the newly generated identifier locally. The security context is KD-sess Updated locally with ID#2, but outdated KD-sess ID#1 is retained at this point and is used just like the old source / destination L2 ID.

[0132] The peer WTRUs are then configured with the same values ​​received in the DIRECT_REKEYING_REQUEST message 1403 (to validate them).KD-sess ID IE new Source L2ID IE and new Source MSB of the KD-sess DIRECT_SECUR including the new Peer LSB of the ID IE In another embodiment, the peer WTRU may send a ITY_MODE_COMMAND message 1405 back to the originating WTRU, which may then be configured to receive the SYNCHRONOUS_MODE_COMMAND message 1405 from the originating WTRU, which is expected to obtain them locally based on the current session context. KD-sess ID IE's new For example, the source WTRU does not send back the new source L2ID IE and new source MSB when it generates KD-sessID The security code identified by the current source MSB of You can store these in the context.

[0133] In block 1406, the source WTRU sends the new L2ID IE of the peer WTRU and the KD-sess DIRECT_ to specify the new LSB of the ID IE Upon receiving the SECURITY_MODE_COMMAND message 1405, it stores these new identities locally. The security association KD-sess ID#2 A new key is generated. The source WTRU notifies the peer of the new L2 ID and KD-sess DIRECT to iterate over the new LSBs of the ID (i.e., verify them) _SECURITY_MODE_COMPLETE message 1407. The peer WTRU responds with its new L2 ID and KD-sess Check the LSB of the ID. The UE receives a DIRECT_SECURITY_MODE_COMPLETE message 1407 acknowledging the rekeying and responds by sending back a DIRECT_REKEYING_RESPONSE message 1408 completing the procedure. From this point on, in block 1409, the new L2 ID and security context, i.e. KD-sessID(MSB and LSB) and key are used.

[0134] Please note that for convenience, most of the procedures in this document are described in terms of interaction between WTRUs from the V2X / NAS layer or higher layers, the same procedures are also applicable at the level of RRC signaling exchange between WTRUs or when PC5 messages are exchanged via the RRC protocol.

[0135] It should be noted that the various figures depicted herein are interrelated and as such share common procedural elements. For example, the example procedures of Method 1 in Figures 6-10 share a common set-up procedure. In a more global example, the procedures of Figures 6-10 are all variations of Method 1 that include the exchange of a new L2 ID between the source WTRU and the peer WTRU. Additionally, Figure 13 illustrates a method for establishing a new session ID using the new MSB of the session ID from the source WTRU and the new LSB of the session ID from the peer WTRU. FIG. 15 illustrates a logical combination of such sharing procedures from the perspective of the source WTRU. In FIG. 15, the procedures of FIG. 6, FIG. 7, and FIG. 13 are illustrated, highlighting options that may be performed using Method 1. Other variations of the depicted example are possible using the techniques depicted herein. Specifically, as shown in FIG. 15, the general operation of Method 1 illustrated in the detailed examples of FIG. 6, FIG. 7, and FIG. 13 is illustrated. FIG. 15 addresses the options of Method 1: (i) communication between source WTRU and peer WTRU updated with new source L2ID only (see FIG. 6), (ii) communication between source WTRU and peer WTRU updated with both new source L2ID and new peer L2ID, or (iii) communication between source WTRU and peer WTRU updated with both new source L2ID and peer L2ID, as well as contribution of MSB and LSB of session ID from source WTRU and peer WTRU to communicate using the new session ID.

[0136] FIG. 15 is a procedure 1500 with options that may be performed by a source WTRU to perform the principles of method 1 described herein. In block 1505, the source WTRU is assumed to have ongoing communication with a peer WTRU. In an example environment, the communication is a PC5 reference link communication in V2X operation where each WTRU has access to a V2X application including privacy application provisions as described herein. In block 1510, a triggering event is detected. Such a triggering event causes a reaction of the source WTRU to perform the operations of blocks 1520 to 1535. Such triggering events may include a timer expiring at the WTRU, a higher layer or application layer of the V2X application requesting a new L2ID, or the source WTRU moving to a new geographical area, or the source WTRU receiving new provisioning parameters from a V2X control function or V2X application server, or the source WTRU receiving a request to change the L2ID from a peer WTRU.

[0137] At block 1520, provided that a triggering event has occurred, the source WTRU may generate a new L2 ID for future communications with the peer WTRU. This is similar to example block 604A of FIG. 6 using method 1. Optionally, at block 1520, the WTRU may also generate a new MSB for a new session ID. This option is a variation of method 1 similar to example block 1302B of FIG. 13. Both FIG. 6 and FIG. 13 share common operational elements as variations of method 1. At block 1525 of FIG. 15, the source WTRU communicates a new source L2 ID value for use with the peer WTRU via messaging to the peer WTRU. The operation of this method 1 is also illustrated in example message 630 of FIG. 6 as an example of a direct communication keep-alive type message. However, as explained above, such messages may be messages commonly known and used between WTRUs or may be specialized messages such as a direct privacy request message between WTRUs. In block 1525 of Figure 15, the communication between the WTRUs may optionally forward the new MSB for the new Session ID as well as the new L2 ID of the source WTRU. This option is a variation of Method 1 shown in example message 1303 of Figure 13 as a Direct Privacy Request type message.

[0138] At block 1530, the source WTRU receives a message from the peer WTRU. The message is responsive to the new source ID and may include a confirmation of the new source L2 ID from the peer WTRU. Such an example of the operation of method 1 is shown in example message 650 of FIG. 6 as a keep-alive confirmation message. However, as noted above, the message type may be any message type used between WTRUs, including a new direct privacy communication message. Optionally, as shown in FIG. 15, the message may be a new source L2 ID. If the operation of method 1 in block 1530 of includes generating a new peer WTRU L2ID, as in the operation of method 1 of Figure 7, then the message of block 1530 may include both the new source L2ID and confirmation of the new peer WTRU L2ID. A message including both the new source and new peer L2ID is a variation of method 1 shown in example message 750 of Figure 7. A third option of block 1530 of Figure 15 includes a variation of method 1 shown in Figure 13, which includes information of the new source L2ID, the new peer L2ID, the new MSB of the new session ID, and the new LSB from the peer WTRU for use in the new session ID. In the option to use the new session ID, after receiving the new MSB and LSB, the source WTRU generates a new session ID for communications between the source WTRU and the peer WTRU, as described with respect to Figure 13.

[0139] In block 1535, the source WTRU may communicate with the peer WTRU using or based on the new source L2ID. This operation is included in the method 1 operation as shown in example block 607 of FIG. 6. Optionally, if the method 1 operation includes changing both the source L2ID and the peer L2ID, as in the method 1 operation of FIG. 7, block 1535 of FIG. 15 enables the source WTRU to communicate with the peer WTRU using the new source L2ID and the new peer L2ID. This operation is also shown in the method 1 operation of example block 707 of FIG. 7. In block 1535 of FIG. 15, a further method 1 option is for the source WTRU to communicate with the peer WTRU using the new source L2ID, the new peer L2ID, and a new session ID that includes the MSB contribution from the source WTRU and the LSB contribution from the peer WTRU. This method 1 operation is shown in example block 1308 of FIG. 13.

[0140] Thus, Method 1 is shown as having some general operations that allow for various variations depending on whether communications between the source WTRU and the peer WTRU are updated with only the new source L2ID, with both the new source L2ID and the peer L2ID, or with both the new source L2ID and the peer L2ID and MSB and LSB contributions from the source and peer WTRUs, respectively, to communicate with the new session ID.

[0141] Although features and elements are described above in certain combinations, one skilled in the art will understand that each feature or element can be used alone or in any combination with the other features and elements. Additionally, the methods described herein can be implemented in a computer program, software, or firmware embodied in a computer-readable medium for execution by a computer or processor. Examples of computer-readable media include electronic signals (transmitted over wired or wireless connections) and computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, read-only memory (ROM), random-access memory (RAM), registers, cache memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magneto-optical media, optical media such as CD-ROM disks, digital versatile disks (DVDs), and the like. A processor in association with software can be used to implement a radio frequency transceiver for use in a WTRU, UE, terminal, base station, RNC, or any host computer.

[0142] In an exemplary embodiment, any of the operations, processes, etc. described herein may be implemented as computer-readable instructions stored on a computer-readable medium. The computer-readable instructions may be executed by a processor of a mobile unit, a network element, and / or any other computing device.

[0143] The foregoing detailed description illustrates various embodiments of devices and / or processes through the use of block diagrams, flow charts, and / or examples. To the extent that such block diagrams, flow charts, and / or examples include one or more functions and / or operations, it will be understood by those skilled in the art that each function and / or operation in such block diagrams, flow charts, or examples can be individually and / or collectively implemented by a wide range of hardware, software, firmware, or substantially any combination thereof. Suitable processors include, by way of example, general purpose processors, special purpose processors, conventional processors, digital signal processors (DSPs), multiple microprocessors, one or more microprocessors associated with a DSP core, controllers, microcontrollers, application specific integrated circuits (ASICs), application specific standard products (ASSPs), field programmable gate array (FPGA) circuits, other types of integrated circuits (ICs), and / or state machines.

[0144] Although features and elements are provided above in specific combinations, one skilled in the art will understand that each feature or element can be used alone or in any combination with other features and elements. The present disclosure is not limited with respect to the specific embodiments described in this application, which are intended as illustrations of various aspects. As will be apparent to those skilled in the art, many variations and modifications may be made without departing from the spirit and scope of the present disclosure. No element, act, or instruction used in the description of this application should be construed as critical or essential to the invention unless expressly provided as such. In addition to the methods and devices recited herein, functionally equivalent methods and devices within the scope of the present disclosure will be apparent to those skilled in the art from the foregoing description. Such variations and modifications are intended to be within the scope of the appended claims. The present disclosure should be limited only by the terms of the appended claims, and the full scope of equivalents to which such claims are entitled. It is understood that this disclosure is not limited to any particular method or system.

[0145] It should also be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the terms "station" and its abbreviation "STA", "user equipment" and its abbreviation "UE" when referred to herein may mean (i) a wireless transmit and / or receive unit (WTRU) as described in detail, (ii) any of some embodiments of a WTRU as described in detail, (iii) a wireless-enabled and / or wired-enabled (e.g., tetherable) device configured with some or all of the structure and functionality of a WTRU, particularly as described in detail, (iii) a wireless-enabled and / or wired-enabled device configured with less than all of the structure and functionality of a WTRU, as described in detail, or (iv) others.

[0146] Generally, the terms used herein, and particularly in the appended claims (e.g., the body of the appended claims), are generally intended as "open" terms (e.g., the term "including" should be interpreted as "including but not limited to," the term "having" should be interpreted as "having at least," the term "includes" should be interpreted as "includes but is not limited to," etc.). Where a particular number of incorporated claims is intended, such intent will be expressly set forth in the claim, and in the absence of such a statement, it will be further understood by those skilled in the art that no such intent exists. For example, where only one item is intended, the term "single" or similar language may be used. To aid in understanding, the following appended claims and / or this specification may be modified in any manner to suit the purposes of the present invention. The description of the document includes the introductory phrase "at least one" to introduce the recitation of a claim.The use of "one" and "one or more" may include the use of "one" and "one or more". However, flowever, the use of such phrases should not be construed as meaning that the introduction of a claim recitation with the indefinite article "a" or "an" limits any particular claim containing such an introduced claim recitation to embodiments including only one, even if the same claim contains the introductory phrase "one or more" or "at least one" and an indefinite article such as "a" or "an" (e.g., "a" and / or "an" should be construed to mean "at least one" or "one or more"). The same applies to the use of definite articles used to introduce claim recitations. Furthermore, even if a particular number of an introduced claim recitation is explicitly recited, a person skilled in the art will recognize that such recitation should be interpreted to mean at least the recited number (e.g., the bare recitation "recited twice" without other modifiers means at least two recitations, or more than two recitations). Furthermore, where there is a convention similar to "at least one of A, B, and C, etc.", such a configuration is generally intended in the sense that a person skilled in the art would understand the convention (e.g., "a system having at least one of A, B, and C" includes, but is not limited to, a system having only A, a system having only B, a system having only C, a system having both A and B, a system having both A and C, a system having both B and C, and / or a system having both A, B, and C, etc.).Additionally, where there is a convention similar to "at least one of A, B, or C, etc.", such a configuration is generally intended in the sense that one of ordinary skill in the art would understand the convention (e.g., "a system having at least one of A, B, or C" includes, but is not limited to, a system having only A, a system having only B, a system having only C, a system having both A and B, a system having both A and C, a system having both B and C, and / or a system having both A, B, and C, etc.). One of ordinary skill in the art will further appreciate that any disjunctive word and / or phrase, whether in the specification, claims, or drawings, that substantially presents two or more alternative terms, should be understood to contemplate the possibility of including either one term, either the other term, or both terms. For example, the phrase "A or B" will be understood to include the possibilities of "A" or "B" or "A and B." Additionally, as used herein, the term "any" followed by a list of items and / or categories of items is intended to include "any," "any combination," "any plurality," and / or "any combination of items and / or categories of items, either individually or in combination with other items and / or items from other categories." Additionally, as used herein, the term "set" or "group" is intended to include any number of items, including zero. Additionally, as used herein, the term "number" is intended to include any number, including zero.

[0147] Furthermore, when features or aspects of the disclosure are described in terms of a Markush group, those skilled in the art will recognize that the disclosure is also thereby described in terms of any individual members or subgroups of members of the Markush group.

[0148] As will be understood by those of ordinary skill in the art, in terms of providing a written description, all ranges disclosed herein encompass any and all possible subranges and combinations of subranges. Any range described can be readily recognized as fully describing the same range and allowing it to be broken down into at least equal halves, thirds, quarters, fifths, tenths, etc. As a non-limiting example, the ranges disclosed herein are Each range discussed can be easily broken down into a lower third, a middle third, an upper third, etc. As will be appreciated by one of skill in the art, all language such as "up to," "at least," "greater than," "less than," etc., includes the recited numbers and refers to ranges that can then be broken down into subranges as discussed above. Finally, as will be appreciated by one of skill in the art, ranges include individual members. Thus, for example, a group having 1-3 cells refers to groups having 1, 2, or 3 cells. Similarly, a group having 1-5 cells refers to groups having 1, 2, 3, 4, or 5 cells, and so forth.

[0149] Moreover, the claims should not be construed as limited to the order or elements provided unless so stated. Moreover, the use of the term "means for" in any claim is intended to invoke 35 U.S.C. ...

[0150] A processor in association with software may be used to implement a radio transmit receive unit (WTRU), user equipment (UE), terminal, base station, mobility management entity (MME) or evolved packet core (EPC), or a radio frequency transceiver for use in any host computer. The WTRU may be used in combination with hardware and / or software including software defined radios (SDRs) and modules implemented in other components, such as cameras, video camera modules, videophones, speakerphones, vibration devices, speakers, microphones, television transceivers, hands-free headsets, keyboards, Bluetooth modules, frequency modulation (FM) radio units, near field communications (NFC) modules, liquid crystal display (LCD) display units, organic light emitting diode (OLED) display units, digital music players, media players, video game player modules, Internet browsers, and / or wireless local area network (WLAN) or ultra-wideband (UWB) modules.

[0151] Throughout this disclosure, those skilled in the art will understand that certain representative embodiments may be used in the alternative or in combination with other representative embodiments.

[0152] Additionally, the methods described herein may be implemented in a computer program, software, or firmware embodied in a computer-readable medium for execution by a computer or processor. Examples of non-transitory computer-readable storage media include, but are not limited to, read-only memory (ROM), random access memory (RAM), registers, cache memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magneto-optical media, optical media such as CD-ROM disks, digital versatile disks (DVDs), and the like. A processor in association with software may be used to implement a radio frequency transceiver for use in a WTRU, UE, terminal, base station, RNC, or any host computer.

Claims

1. 1. A method for use in an ongoing Vehicle-to-Everything (V2X) session, comprising: communicating between a source wireless transmit / receive unit (WTRU) and a peer WTRU based on a source layer 2 (L2) identifier (ID); Provided that a trigger event occurs, generating a new source L2 ID for the source WTRU; communicating the new source L2 ID to the peer WTRU; and receiving a message from the peer WTRU responding to the new source L2 ID; communicating between the source WTRU and the peer WTRU based on the new source L2 ID.

2. The method of claim 1 , further comprising: after communicating the new source L2 ID to the peer WTRU, receiving a new peer L2 ID by the source WTRU.

3. 3. The method of claim 2, wherein communicating between the source WTRU and the peer WTRU using the new source L2 ID further comprises communicating between the source WTRU and the peer WTRU using the new source L2 ID and the new peer L2 ID.

4. generating a new Most Significant Byte (MSB) of a session ID to be used to communicate with the peer WTRU in conjunction with generating the new source L2 ID; communicating the new source L2 ID to the peer WTRU along with the new MSB of the session ID; receiving, by the source WTRU, a new least significant byte (LSB) of the session ID from the peer WTRU in conjunction with receiving, by the source WTRU, a new peer L2 ID; 4. The method of claim 2, further comprising: communicating between the source WTRU and the peer WTRU using the new source L2 ID and the new peer L2 ID using a new session ID including the new MSB and the new LSB.

5. The method of any one of claims 1 to 4, wherein communicating the new source L2 ID to the peer WTRU includes communicating using one of a keep-alive procedure, a privacy procedure, or another communication procedure used between the source WTRU and the peer WTRU.

6. The method of any one of claims 1 to 5, further comprising: communicating the new source L2 ID across a layer on the source WTRU prior to communication between the source WTRU and the peer WTRU based on the new source L2 ID.

7. The condition for a trigger event to occur is The condition that the timer expires, A condition where the upper layer or application layer of the V2X application requests a new L2 ID; a condition that the source WTRU has moved to a new geographic region; the source WTRU has received new provisioning parameters from a V2X control function or a V2X application server; or The method of any one of claims 1 to 6, including any of the conditions: the source WTRU receives a request from the peer WTRU to change its L2 ID.

8. The method according to any one of claims 4 to 7, wherein the session ID is a security context session ID.

9. The method of any one of claims 1 to 8, wherein communicating between the source WTRU and the peer WTRU includes communicating over a PC5 reference link.

10. 1. A source wireless transmit / receive unit (WTRU) comprising a circuit including a transmitter, a receiver, a processor, and a memory, the WTRU comprising: communicating between the source WTRU and a peer WTRU based on a Layer 2 (L2) identifier (ID) using the transmitter and receiver; Provided that a trigger event occurs, generating a new source L2 ID for the source WTRU; and communicating the new source L2 ID to the peer WTRU; and communicating between the source WTRU and the peer WTRU based on the new source L2 ID.

11. The WTRU: The source WTRU of claim 10, further configured to receive, by the receiver, a new peer L2 ID after communicating the new source L2 ID to the peer WTRU.

12. The WTRU: The WTRU of claim 11 , configured to communicate between the source WTRU and the peer WTRU based on the new source L2 ID and the new peer L2 ID.

13. The WTRU: generating a new Most Significant Byte (MSB) of a session ID to be used to communicate with the peer WTRU in conjunction with generating the new source L2 ID; communicating the new source L2 ID to the peer WTRU along with the new MSB of the session ID; receiving, by the source WTRU, a new least significant byte (LSB) of the session ID from the peer WTRU in conjunction with receiving, by the source WTRU, a new peer L2 ID; and communicating between the source WTRU and the peer WTRU based on the new source L2 ID and the new peer L2 ID using a new session ID including the new MSB and the new LSB.

14. 12. The WTRU of claim 11, wherein the triggering event includes at least one of expiration of a timer, a request for a new L2 ID from a higher layer or application layer of a V2X application, movement of the source WTRU to a new geographical area, receipt by the source WTRU of new provisioning parameters from a V2X control function or a V2X application server, or receipt by the source WTRU of a request from the peer WTRU to change an L2 ID.

15. When executed by a computer, the computer is caused to A computer readable storage medium containing instructions for performing the method described above.

Images