Steps to enable privacy for the 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 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 communication. 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 responsive 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 contribution of the most significant byte (MSB) and the least significant byte (LSB). The source WTRU generates new MSBs of the session ID to be used to communicate with the peer WTRU and also generates a new source L2ID. The source WTRU communicates the new MSBs 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, containing the new MSB and new LSB of the session ID.

[0007] In one embodiment, the function of communicating the new source L2ID 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 L2ID over a layer above the source WTRU before communicating with the peer WTRU based on the new source L2ID.

[0008] In one embodiment, the triggering events that cause at least a change in the source L2ID may include 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. Upon occurrence of a trigger event, 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 include instructions that, when executed by a computer, cause the computer to perform any of the methods described herein. [Brief explanation 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 numerals 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] 1B is a system diagram illustrating an example of a wireless transmit / receive unit (WTRU) that can be used within the communication system shown 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 can be used in the communication system shown in FIG. 1A, according to one embodiment. [Figure 1D] 1B is a system diagram illustrating a further exemplary RAN and a further exemplary CN that can be used within the communication system shown in FIG. 1A, according to one embodiment. [Figure 2] 1 shows an example of the security context ID format of the PDCP header for point-to-point communication. [Figure 3] 10 is a sequence chart outlining an example of changing the source WTRU L2 ID. [Figure 4] 10 is a sequence chart illustrating an example of privacy parameter provisioning. [Figure 5]10 is a sequence chart showing an example of such a direct link setup procedure. [Figure 6] 10 is a sequence chart illustrating an example of exchanging a new L2 identifier using an updated keep-alive procedure. [Figure 7] 10 is a sequence chart illustrating an example of a source and peer WTRU updating their L2 IDs during the same procedure. [Figure 8] 10 is a sequence chart showing an example of a privacy procedure for a single L2 ID change. [Figure 9] 10 is a sequence chart illustrating an example of source WTRU and peer WTRU L2IDs being updated during the same procedure. [Figure 10] 10 is a sequence chart illustrating an example in which a peer WTRU triggers an L2 ID change procedure. [Figure 11] 10 is a sequence chart illustrating an example procedure by which a source WTRU configures a peer WTRU and source WTRU L2 ID update. [Figure 12] 10 is a sequence chart illustrating privacy timer value and seed configuration. [Figure 13] 10 is a message sequence chart illustrating the case where both WTRUs exchange new parts of the session ID using privacy procedures. [Figure 14] 10 is a message sequence chart illustrating the exchange of a new L2 ID using an 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 INVENTION

[0014] 1A illustrates an exemplary communication system 100 in which one or more disclosed embodiments can be implemented. The communication system 100 may be a multi-access system that provides content, such as voice, data, video, messaging, and broadcasts, to multiple wireless users. The communication system 100 may enable the multiple wireless users to access such content through the 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 filtering OFDM, filter bank multicarrier (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 conjunction with 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 industrial and / or automated processing chains), 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 communications 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 communications 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 Fl ome Node-B, a Fl ome eNode-B, a gNB, an NR Node-B, a site controller, an access point (AP), a wireless router, etc. While 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 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 for a particular geographic area, which 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 utilize multiple transceivers for each sector of the cell. For example, beamforming can be used to transmit and / or receive signals in desired spatial directions.

[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 high-speed packet access (GPA) technology. The HSPA may include communication protocols such as 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 jointly implement LTE radio access and NR radio access, 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., Worldwide 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 a business, 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 radio 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 radio 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 through 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. The CN 106 / 115 may be any type of network configured to provide a RAN (Routing Node B) service. The data may have 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, billing 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 communicate directly or indirectly 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 network 112 may include wired and / or wireless communication networks owned and / or operated by other service providers. For example, the network 112 may include another CN connected to one or more RANs, which may use the same RAT as the RAN 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 802.2 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 they 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 understood 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 a speaker / microphone 124, a keypad 126, and / or a 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. Furthermore, 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, etc. 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 walkie-talkie, 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, etc. 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 for transmitting and receiving 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) in parallel and / or simultaneously. The full-duplex radio may include an interference management unit 139 for reducing and / or substantially eliminating self-interference via either hardware (e.g., a choke) or a processor (e.g., signal processing via a separate processor (not shown) or processor 118). In one embodiment, the WTRU 102 may include a half-duplex radio for transmitting and receiving 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, and 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, and 160c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, and 102c over the air interface 116. In one embodiment, the eNode-Bs 160a, 160b, and 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 each other 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. While 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 anchoring 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 communication 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, it is contemplated that in certain representative embodiments such a terminal may use a wired communication interface with the communication network (e.g., temporarily or permanently).

[0047] In a representative 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 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 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 within 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 the destination STA. Traffic between STAs within 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 Direct Link Setup (DLS). In certain representative embodiments, DLS may use 802.11e DLS or 802.11z Tunneled DLS (TDLS). A WLAN using Independent BSS (IBSS) mode may not have an AP, and STAs within or using the IBSS (e.g., all STAs) 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 operation or a similar mode of operation, an AP may transmit beacons on a fixed channel, such as a primary channel. The primary channel may be a fixed width (e.g., a wide 20 MHz bandwidth) or a width dynamically set via signaling. The primary channel may be the 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 the 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 can support channels of 20 MHz, 40 MHz, 80 MHz, and / or 160 MHz width. A 40 MHz and / or 80 MHz channel can be formed by combining contiguous 20 MHz channels. A 160 MHz channel can be formed by combining eight contiguous 20 MHz channels or two non-contiguous 80 MHz channels. This is sometimes referred to as an 80+80 configuration. For the 80+80 configuration, after channel encoding, the data can be passed through a segment parser to split the data into two streams. Inverse fast Fourier transform (IFFT) processing and time-domain processing can be performed separately on each stream. The streams can be mapped to two 80 MHz channels, and the data can be transmitted by the transmitting STA. At the receiver of the receiving STA, the above operations for the 80+80 configuration can be reversed, and the combined data can 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-based communication, such as an MTC device. An MTC device may have limited functionality, including support for (e.g., support only) a specific bandwidth and / or limited bandwidth. An MTC device may include a battery with above-threshold battery life (e.g., to maintain very long battery life).

[0053] WLAN systems that may support multiple channels and channel bandwidths, such as 802.11n, 802.11ac, 802.11af, and 802.11ah, include a channel that can be designated as the 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 configured 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 of a STA (e.g., an MTC-type device) that supports (e.g., only supports) 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) configuration may depend on the status of the primary channel. For example, if the primary channel is busy because a STA (supporting only the 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, and 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, and 180c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, and 102c over the air interface 116. In one embodiment, the gNBs 180a, 180b, and 180c may implement MIMO technology. For example, the gNBs 180a, 180b may utilize beamforming to transmit signals to and / or receive signals from the gNBs 180a, 180b, and 180c. Thus, the gNB 180a may, for example, use multiple antennas to transmit wireless signals to and / or receive wireless signals from the WTRU 102a. In one embodiment, the gNBs 180a, 180b, 180c may implement carrier aggregation technology. 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 unlicensed spectrum, and the remaining component carriers may be on licensed spectrum. In one embodiment, the gNBs 180a, 180b, 180c may implement coordinated multipoint (CoMP) technology. For example, the WTRU 102a may receive coordinated transmissions from the gNBs 180a and 180b (and / or 180c).

[0057] The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using transmissions related to 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 may communicate with the gNBs 180a, 180b, 180c using subframes or transmission time intervals (TTIs) of varying or scalable lengths (e.g., different lengths of absolute time including and / or lasting 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 can communicate with the gNBs 180a, 180b, 180c without accessing another RAN (e.g., eNode-Bs 160a, 160b, 160c, etc.). In a standalone configuration, the WTRUs 102a, 102b, 102c can utilize one or more gNBs 180a, 180b, 180c as mobility anchor points. In a standalone configuration, the WTRUs 102a, 102b, 102c can 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. While 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. The AMF 162 may be responsible for CN support, 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. 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 and 183b may be connected to the AMFs 182a and 182b in the CN 115 via an N11 interface. The SMFs 183a and 183b may also be connected to the UPFs 184a and 184b in the CN 115 via an N4 interface. The SMFs 183a and 183b may select and control the UPFs 184a and 184b and configure the routing of traffic through the UPFs 184a and 184b. The SMFs 183a and 183b may perform other functions such as managing and assigning UE IP addresses, managing PDU sessions, controlling policy enforcement and QoS, and providing downlink data notifications. 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 acts 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 one embodiment, the WTRUs 102a, 102b, 102c may connect to the 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 being 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, for example, include 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. Herein, a source WTRU is interchangeably referred to as a requesting 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 WTRU-to-WTRU communication may be based on two modes of operation. In the first mode, V2X WTRU-to-WTRU communication can occur over the LTE-Uu interface. In the second mode, V2X WTRU-to-WTRU communication can occur 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 IDs (IDs) of both itself and the peer (target) WTRU. The target WTRU's L2 ID 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, it sends the L2I 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 function that can be used to detect if a WTRU is not within ProSe communication range, e.g., it can proceed with an implicit L2 link release. 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 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 can be created between peer WTRUs to protect the link (i.e., to facilitate confidentiality and integrity protection). Each peer WTRU locally maintains a security context that contains the keys to encrypt / decrypt messages and ensure message integrity. This security context is associated with this particular peer-to-peer link. The security association identifier ( KD-sess (which may be referred to as a message ID) A session identifier (i.e., a session ID) may be used by each peer WTRU to identify and obtain 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) is assigned to 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 8 least significant bits) of the ID is from the peer WTRU. KD-sess That part of the ID (i.e., MSB or L SB) to obtain the security context associated with the link.

[0075] 2 illustrates an example Packet Data Convergence Protocol (PDCP) header 200 for point-to-point communication. 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 PDCP counter 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, for example, using unicast and / or multicast. Such mechanisms may utilize long duration sessions using the same source L2ID. This can create privacy issues if the source L2IDs are tracked and linked. Such privacy issues affect both peers, i.e., the source WTRU and the 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 changes at the source WTRU, it may need to notify the peer WTRU, 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 introduce 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, e.g., 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 L2ID change is acknowledged by the peer WTRU. Such a requirement may create or require inefficient procedures, e.g., multiple message exchanges, because 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 communication 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 WTRUs involved in the communication can assume the roles of source and / or target, respectively, depending on the peers through which the particular exchange is taking place. 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 used for a specific period of time 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 using it, e.g., the application transmitting 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 the ProSe PC5 interface). It may also apply 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., a 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 the 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 notified when the other WTRU changes its L2ID. The new source and target L2IDs associated with an ongoing session can 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 L2ID at the peer WTRU. For example, the regeneration and update of the L2ID may be triggered by a timer expiration, receipt of a new L2ID value from the peer WTRU, an update of the associated application ID, a request from the peer WTRU, a change in communication context, or other event. While the high-level view and exemplary methods described below are detailed based on a privacy timer for purposes of example, it will be 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 described above, in some implementations, a WTRU with multiple sessions using the same L2ID needs to update all sessions / peers simultaneously (or within a defined time period, e.g., a short time period). In some implementations, for each session, the WTRU needs to continue receiving traffic on the old L2ID until the L2ID change is confirmed by the peer WTRU. This can make the L2ID change mechanism inefficient, 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. Furthermore, each session with the same peer WTRU can be associated with only one application. Furthermore, multiple applications running on the source / target WTRU can all use separate sessions.

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

[0087] 3, reference block 301, 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. Privacy policies are 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 in the WTRU (e.g., in either the Mobile Equipment (ME) or Universal Integrated Circuit Card (UICC)). These parameters can be provisioned per WTRU (e.g., to be used for all ProSe / V2X direct communications for a particular WTRU) or based on a per-V2X application ID (e.g., an Intelligent Transportation Systems Application Identifier (ITS-AID) or a Provider Service Identifier (PSID)) (e.g., to be used for all ProSe / V2X direct communications for a particular V2X application). At reference block 302 of FIG. 3, PC5 communications are established between a source WTRU and a peer WTRU (referred to as UE in FIG. 3). The peer WTRU may be provisioned with the source WTRU's privacy-specific parameters (as described above), for example, during session establishment (and vice versa). The privacy policy received at the peer WTRU may be compared with the peer WTRU's provisioned policy, and the best matching privacy protection method may be selected. The source WTRU may be provisioned with the peer WTRU's privacy-specific parameters (as described above), for example, during link establishment. Blocks 301 and 302 of Figure 3 represent the setup procedure for PC5 communication.

[0088] At blocks 303A and 303B of Figure 3, a privacy timer is started at the source WTRU (and optionally the peer WTRU). At block 304 of Figure 3, communication continues between the source L2ID#1 (and the peer L2ID#1) and KD-sess Use ID#1 3. 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+ KD-sess (It is assumed that identity privacy is ensured). 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 ID current Associated with the source L2ID and current MSB. At this point, the existing source L2ID (Source L2ID#1) and possibly the session ID ( KD-sess ID#1) continues to be used to identify the ongoing session. 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., one) to the peer WTRU, or the peer WTRU itself regenerates the 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 there may be cases where the ID does not need to be updated. In this state, the same procedure can be performed simultaneously on both WTRUs to change the L2ID and possibly the Session ID in the same procedure. The privacy timer is just one example of a trigger for changing the L2ID and Session ID. The L2ID and Session ID can also be It may also be generated and subsequently communicated to other WTRUs, for example, when the WTRU receives, for example, a new source L2ID from a peer WTRU, when a higher layer or application layer triggers privacy procedures, 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 privacy procedures 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., by a timer, a request from a peer, etc., the V2X layer can notify / 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 instructions from the V2X layer to the application and responses from the application to the V2X layer.

[0090] In blocks 306A and 306B, the new source (and optionally peer) L2ID 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. Upper 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 ( KD-sess new peer L2ID#2 is used for the ongoing session. Once configured, it is also used for ongoing sessions, as in block 306A1. In blocks 307A and 307B, the privacy timer is restarted at the source WTRU (and optionally at 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 a 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 modifying existing messages (such as ProSe keep-alive messages) to carry the new source L2 ID, for example to support parallel exchange of new source and peer L2 IDs. A further extension of Method 1, hereinafter referred to as Method 3, includes: KD-sess ID's new MS 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 a peer trigger. 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 includes 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 rekey 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 the 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 using a V2X application server. A zero value configuration may disable the source L2ID regeneration procedure. If no provisioning is provided, default values ​​can 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 a configuration. For example, there may be the following values: PPM1 (disabled - no privacy processing), PPM2 (L2ID privacy using method 1 only, single UE L2ID update), PPM3 (L2ID privacy using method 1 only, L2ID update for both UEs), PPM4 (L2ID privacy using method 2 only, 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 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 occurs when the AMF It may be considered "transparent" because 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 it is 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 another WTRU during an ongoing PC5 session that an L2ID change is required in the current session. This can be achieved, 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. For this purpose, a new Privacy Timer IE containing the privacy timer value can be introduced. A new Privacy Indication IE may also be introduced and set to a provisioned value, e.g., PPM2, PPM3, PPM4 (as described above). The PPM selection 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. Therefore, 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 particular 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, and each application has a specific privacy policy). The peer WTRU may reject the link setup if it cannot find an acceptable (e.g., common) PPM based on its 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 the request message from the destination or target or peer WTRU 520 to the requester or source WTRU 510, which confirms the privacy indication, the source WTRU privacy timer, and / or the 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 their L2 IDs will change during the lifetime of the session. A WTRU receiving a privacy timer setting from a peer can expect a change within the time specified by the privacy timer value. If the change does not occur within this period, the receiving WTRU may trigger a replacement of this ID, e.g., using the privacy procedures shown and described with respect to FIG. 9.

[0101] An example of Method 1 referenced above will now be described. Some examples of Method 1 include the exchange of a new L2 identifier. In some examples, the WTRU exchanges new L2 IDs one after the other, either during the same procedure or independently. The privacy timer value is updated 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. Existing keep-alive messages 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 the 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, in which only the source L2 ID is changed. Note that 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 result. 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 L2ID#1 (and the peer L2 ID). At block 604, the privacy timer expires at the source WTRU 610 and the source L2ID needs to be updated. At block 604A, a new source L2ID 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 L2ID in a new IE (e.g., Source_L2J DJ 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 that 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 L2ID associated with the session and stores it locally. Both L2IDs (old and new) can be stored locally in case messages using the old ID have been forwarded during the ID change procedure.The peer WTRU stops the keep-alive timer in 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. In step 4c, the keep-alive timer is restarted on both sides. In blocks 605A and 605B, the new source L2ID 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 L2ID for PC5 communication). In block 606, the source WTRU restarts its privacy timer because the source L2ID needs to be changed periodically. In block 607, the new source L2 ID is used from this point on from both sides.

[0104] In some cases, both WTRUs update their L2 IDs in the same procedure. The target WTRU may decide to update its L2ID 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 L2IDs 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 to both WTRUs. In blocks 704A and 704B, the privacy timer expires in the source and peer WTRUs, requiring the L2ID 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 containing 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 ID and new ID) can be stored locally in case a message using the old ID is being forwarded during the ID change procedure. Because 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 as received in the keep-alive message (i.e., source L2ID#1). It also contains the new ID in another new IE (e.g., target_L2JDJE). The old L2ID continues to be used as the source / destination ID for this message. After receiving the response message, the source WTRU replies 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 because 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 by the source WTRU or the peer WTRU. This procedure can be used to update the L2 ID of a single WTRU or 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 can 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. In blocks 805A and 805B, the new source L2 ID is synchronized / communicated across layers on both WTRUs for PC5 communication (e.g., where the higher layers know which WTRU ID to use and the AS layer uses the L2 ID for PC5 communication). In block 806, the source WTRU restarts the privacy timer. In block 807, the new source L2 ID can 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] In block 901, V2X parameters are provisioned in the WTRU and a session is set up. In blocks 902A and 902B, the source WTRU 910 and the peer WTRU 920 start a privacy timer using the provisioned values. In block 903, communication is ongoing between the source WTRU and the peer WTRU. In blocks 904A and 904B, the privacy timer expires in the source WTRU and possibly the peer WTRU. In 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 source WTRU's new source L2ID and stores it locally. In 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 receiving a privacy request message 930. The peer WTRU sends back a Privacy_Response message 940 containing a new source L2ID IE set to the same value received in the privacy request message and also containing a 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. In blocks 905A and 905B, the new L2ID is generated (e.g., when upper 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. From this point on, in block 907, 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, for example, (a) receive a trigger locally (e.g., from a higher layer) or determine that the source L2ID needs to be changed (e.g., due to an appropriate reason or additional trigger), or (b) if 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 example steps of method 1 in which a peer WTRU triggers an L2ID 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 L2ID, and the peer L2ID may need to be changed as well. The peer WTRU sends a new Privacy_Trigger message 1030 to the source WTRU. If the L2ID needs to be updated in optional block 1004B1, the peer WTRU can generate a new L2ID. Otherwise, the source WTRU receiving this trigger message 1030 stops its privacy timer in block 1005. In block 1005A1, a new source L2 ID (e.g., source L2ID#2) is generated. In block 1005A2, the source WTRU initiates privacy procedures to send its new ID to the peer WTRU. Direct privacy messages are exchanged in block 1006. Alternatively, the source WTRU may send the new source L2 ID to the peer WTRU using a keep-alive procedure, for example, 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. In blocks 1007A and 1007B, the new L2 ID is synchronized / communicated across layers on both WTRUs for PC5 communication (e.g., where the higher layers know which WTRU ID to use and the AS layer uses the L2 ID for PC5 communication). At blocks 1008A and 1008B, the privacy timer is restarted in both WTRUs.At block 1009, communication is in progress using the new source L2ID#2 and, if changed, the new peer L2ID#2.

[0112] An example of Method 2 L2ID change includes generating a peer L2ID at the source and target WTRUs. In some Method 2 examples, the peer L2ID is 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 are exchanged and communications are 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) seed to be used for new L2 ID regeneration.

[0114] The WTRUs may use the same seed or a different seed value (e.g., provisioned for generating the timer) to generate the privacy timer. If different seeds are used to generate the timer values, 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 target WTRU's new L2ID may be selected consecutively from the list of seeds provided after the privacy timer expires. The WTRU starts the peer_privacy_timer and, when the timer expires, 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 target WTRU's new L2ID may be done periodically. The seed and timer values ​​may be configured by 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 regenerate the 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. At block 1101, a session is set up between the source WTRU and the peer WTRU. At block 1102, communication between the source WTRU and the peer WTRU is ongoing. At this point, "Source L2ID#1" is used. At block 1102A, a privacy timer is started at the source WTRU. At block 1103, the 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 sides' 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 FIGS. 6 and 8 can be used here, but in this case (new IE for the seed) the privacy timer + seed is transferred. 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 timer has 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 communication (e.g., where the higher layers know which WTRU ID to use and the AS layer uses the L2 ID for PC5 communication). At blocks 1106A and 1106B, the privacy timer is restarted on both WTRUs. At block 1107, communication is underway 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 / source WTRU sends privacy timer and seed values ​​for each WTRU. In Sequence A, in message 1225, the WTRU 1210 sends a direct communication keepalive, 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 acknowledgment of the received request message 1225. The acknowledgment message 1230 may include the source WTRU privacy timer value and source 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, and 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. 11 of Method 2.

[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 Enhanced with security protection.

[0120] In a first scenario, the initiating / requesting / source WTRU may have a privacy timer running. 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 keepalive 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 a 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 identifier is used upon successful completion of the procedure. Note that the contents of the security context itself are not changed, i.e., the keys and other parameters (such as counters) stored in the security context remain the same, and only the session identifier used to locate the security context locally at the initiating / requestor / source WTRU and peer / destination WTRU (i.e., each peer WTRU) is updated.

[0121] In the second scenario, both WTRUs update their IDs in the same procedure. That is, 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 new L2 IDs. This is shown in Figure 13 using a Direct Privacy message. Figure 13 is a message sequence chart 1300 illustrating 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. This means that each WTRU locally stores a security context containing the security parameters (e.g., encryption keys) required to protect communications. All information exchanged between 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] A privacy timer expires at the source WTRU in block 1302. The source WTRU generates a new source L2ID (e.g., source L2ID#2) in block 1302A, and the source WTRU generates a new source L2ID (e.g., source L2ID#2) in 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 L2ID#2). In block 1304B, the peer WTRU generates a new peer L2 ID (e.g., peer L2ID#3). In block 1304C, the peer WTRU generates a new peer L2 ID (e.g., peer L2ID#4). In block 1304D, the peer WTRU generates a new peer L2 ID (e.g., peer L2ID#5). In block 1304E, the peer WTRU generates a new peer L2 ID (e.g., peer L2ID#6). In block 1304F, the peer WTRU generates a new peer L2 ID (e.g., peer L2ID#7). In block 1304G, the peer WTRU generates a new peer L2 ID (e.g., peer L2ID#8). In block 1304H, the peer WTRU generates a new 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). In 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 Contains the new source L2ID IE and the new source MSB of the ID IE. R,KD-sess Also includes new peer L2ID IE and new peer LSB in ID IE In another embodiment, the peer WTRU may be equipped with a source WTRU that is expected to obtain them locally based on the current session context. KD-sess ID IE New For example, the source WTRU does not send back the new source L2ID IE and new source MSB. KD-sess Security identified by the current source MSB of the ID In block 1306, the source WTRU receiving the privacy response message 1305 may 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. Block 1308 responds with the new L2ID and KD-sess The ID (MSB and LSB) is used.

[0126] In an example of Method 4, an existing rekey procedure can be augmented by exchanging a new L2 ID. In one example, Method 4, an existing rekey procedure can be augmented by exchanging a new L2 ID between 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 the 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 cycled with the current key, etc.).

[0128] Note that the rekey procedure may imply changing the complete session ID, i.e., the 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, the L2ID change can be performed by only a single WTRU or by both WTRUs, as needed.

[0129] FIG. 14 is a message sequence chart 1400 illustrating the exchange of a new L2ID using an enhanced rekey procedure. FIG. 14 provides an example use of method 4, which provides for the exchange of L2IDs for both the source WTRU and the peer WTRU in the context of a rekey procedure. In block 1401, communication is in progress between the source WTRU and the peer WTRU. The source WTRU 1410 is using L2ID#1 and the peer WTRU 1420 is using its own L2ID#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 containing 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 New MSB (i.e., KD-sess The source WTRU generates the new New Source L2ID IE and new MSB of KD-sess ID, and optionally new The RADIUS server 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 sends 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 old 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 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 also includes 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 source WTRU. In another embodiment, the peer WTRU may send a ITY_MODE_COMMAND message 1405 back to the source WTRU with the source WTRU expecting to obtain them locally based on the current session context. KD-sess ID IE New For example, the source WTRU does not send back the new source L2ID IE and new source MSB. 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 new L2ID IE of the peer WTRU. KD-sess DIRECT_ to specify the new LSB of the ID IE Upon receiving the SECURITY_MODE_COMMAND message 1405, the security association stores these new identities locally. 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) The peer WTRU responds by sending a _SECURITY_MODE_COMPLETE message 1407. The peer WTRU sends 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 UE uses 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 presented 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 setup procedure. In a more global example, the procedures of Figures 6-10 are all variations of Method 1 that involve the exchange of a new L2 ID between the source WTRU and the peer WTRU. Furthermore, Figure 13 illustrates the use of the functionality of new session ID generation using new MSBs of the session ID from the source WTRU and new LSBs of the session ID from the peer WTRU. 13。 Method 1 is an extension of the method 1 shown in FIG. 15. FIG. 15 illustrates a logical combination of such a sharing procedure from the perspective of the source WTRU. In FIG. 15, the procedures of FIGS. 6, 7, and 13 are illustrated, highlighting options that may be performed using Method 1. Other variations on the depicted example are possible using the techniques depicted herein. Specifically, as shown in FIG. 15, the general operation of Method 1 shown in the detailed examples of FIGS. 6, 7, and 13 is illustrated. FIG. 15 addresses the following options for Method 1: (i) communication between the source WTRU and the peer WTRU updated with only a new source L2ID (see FIG. 6); (ii) communication between the source WTRU and the peer WTRU updated with both a new source L2ID and a new peer L2ID; or (iii) communication between the source WTRU and the peer WTRU updated with both a new source L2ID and a peer L2ID, with contributions of the MSBs and LSBs of the session ID from the source WTRU and the peer WTRU to communicate using a new session ID.

[0136] FIG. 15 illustrates a methodology 1500 with options that may be performed by a source WTRU implementing the principles of method 1 described herein. In block 1505, the source WTRU is assumed to have ongoing communication with a peer WTRU. In one example environment, this communication is 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 the source WTRU to react 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 its 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 to use with the peer WTRU via messaging to the peer WTRU. The operation of 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 a message may be one commonly known and used between WTRUs, or it may be a specialized message such as a direct privacy request message between WTRUs. In block 1525 of Figure 15, the communication between the WTRUs may optionally transfer 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 in response to the new source ID and may include 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 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 FIG. 7. A third option of block 1530 of FIG. 15 includes a variation of Method 1 shown in FIG. 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 using 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 FIG. 13.

[0139] At 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 operations of Method 1, as shown in example block 607 of FIG. 6. Optionally, if the operations of Method 1 include changing both the source L2ID and the peer L2ID, as in the operations of Method 1 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 operations of Method 1 of example block 707 of FIG. 7. At 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 an MSB contribution from the source WTRU and an LSB contribution from the peer WTRU. This operation of Method 1 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 the communication between the source WTRU and the peer WTRU is 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 the 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 particular combinations, those 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. Furthermore, 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 via 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), etc. 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, which may be executed by a processor of a mobile unit, a network element, and / or any other computing device.

[0143] The foregoing detailed description has illustrated various embodiments of devices and / or processes through the use of block diagrams, flowcharts, and / or examples. To the extent that such block diagrams, flowcharts, and / or examples include one or more functions and / or operations, those skilled in the art will understand that each function and / or operation in such block diagrams, flowcharts, or examples can be individually and / or collectively implemented by a wide range of hardware, software, firmware, or virtually 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] While features and elements are provided above in specific combinations, those 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. It will be apparent to those skilled in the art that 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 explicitly provided as such. In addition to the methods and apparatus recited herein, functionally equivalent methods and apparatus 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, 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 specific number of introduced claims is intended, such intent will be explicitly set forth in the claim; absent 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 assist in understanding, the following appended claims and / or this specification may be used to refer to any number of items that are intended to be included in the claims. The description of the document includes the introductory phrase "at least one" to introduce the recitation of the claim.The use of "one" and "one or more" may also be included. However, the use of such phrases should not be construed as meaning that introducing a claim recitation with the indefinite article "a" or "an" limits any particular claim containing such introduced claim recitation to embodiments containing only one, even if the same claim includes 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 interpreted 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 when specific numbers in the introduced claim recitations are explicitly recited, those skilled in the art will recognize that such recitation should be interpreted to mean at least the recited numbers (e.g., the bare recitation "recited twice" without any other modifier means at least two recitations, or more than two recitations). Furthermore, when 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 construction 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 understand 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 term, either other term, or both terms. For example, the phrase "A or B" would 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, 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 skilled in the art, in terms of providing a written description, all ranges disclosed herein encompass any and all possible subranges and combinations thereof. 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 readily broken down into a lower third, middle third, upper third, etc. As will be understood by those skilled in the art, all language such as "up to," "at least," "greater than," "less than," etc., is inclusive of the recited number and refers to a range that can then be broken down into subranges, as discussed above. Finally, as will be understood by those skilled in the art, a range includes individual members. Thus, for example, a group having 1 to 3 cells refers to groups having 1, 2, or 3 cells. Similarly, a group having 1 to 5 cells refers to groups having 1, 2, 3, 4, or 5 cells, and so forth.

[0149] Furthermore, the claims should not be construed as limited to the order or elements provided unless expressly stated to that effect. Moreover, the use of the term "means for" in any claim is intended to invoke 35 U.S.C. 112, paragraph 6 or means-plus-function claim form, and a claim without the term "means for" is not so intended.

[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 walkie-talkies, 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 exemplary embodiments may be used in the alternative or in combination with other exemplary 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), etc. 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. A method for use in a sidelink communication session, comprising: transmitting to or receiving from a peer wireless transmit / receive unit (WTRU) using an existing source WTRU Layer 2 identifier (L2ID), an existing peer WTRU L2ID, and an existing session identifier (ID) used for a session having an existing security context; Provided that said session is in progress and a trigger event occurs, receiving a new source WTRU L2 ID and new 8 most significant bits (MSBs) of a new session ID from the source WTRU; generating, by the peer WTRU, a new peer WTRU L2 ID and new 8 least significant bits (LSBs) of the new session ID; sending, by the peer WTRU, the new peer WTRU L2 ID and the new LSB of the new session ID to the source WTRU; receiving a confirmation of the new peer WTRU L2 ID and the new LSB of the new session ID from the source WTRU; transmitting, by the peer WTRU, to or receiving from the source WTRU using the new source WTRU L2 ID, the new peer WTRU L2 ID, and the new session ID including the new MSB and the new LSB; wherein transmitting to or receiving from the source WTRU occurs according to the new session ID, the new source WTRU L2 ID, and the new peer WTRU L2 ID while maintaining the session using the existing security context.

2. The method of claim 1, wherein receiving the confirmation from the source WTRU includes receiving the confirmation while continuing to use the existing source WTRU L2ID, the existing peer WTRU L2ID, and the existing session ID.

3. The method of claim 1, wherein the new source WTRU L2ID, the new peer WTRU L2ID, and the new session ID are encrypted using the existing security context.

4. The method of claim 1, wherein receiving by the peer WTRU a new source WTRU L2 ID and a new MSB of a new session ID includes receiving a message according to one of a keep-alive procedure, a privacy procedure, a PC5 link update procedure, or another communication procedure.

5. The condition that the session is in progress and a trigger event occurs is satisfied when the session is in progress, and A condition where a higher layer or application layer requests a new L2 ID, or The method of claim 1 , including any of the conditions: the peer WTRU receives a request from the source WTRU to change its L2 ID.

6. The method of claim 1, wherein the session ID is a security context ID.

7. The method of claim 1, wherein transmitting to or receiving from the source WTRU by the peer WTRU includes communicating over a PC5 link.

8. A peer wireless transmit / receive unit (WTRU) comprising circuitry including a transmitter, a receiver, a processor, and a memory, wherein the peer WTRU: transmitting, by the peer WTRU, to or receiving from the source WTRU using the transmitter or receiver, respectively, using an existing source WTRU Layer 2 identifier (L2ID), an existing peer WTRU L2ID, and an existing session ID used for a session having an existing security context; Provided that said session is in progress and a trigger event occurs, receiving a new source WTRU L2 ID and new 8 most significant bits (MSBs) of a new session ID from the source WTRU; generating, by the peer WTRU, a new peer WTRU L2 ID and new 8 least significant bits (LSBs) of the new session ID; sending, by the peer WTRU, the new peer WTRU L2 ID and the new LSB of the new session ID to the source WTRU; receiving a confirmation of the new peer WTRU L2 ID and the new LSB of the new session ID from the source WTRU; transmitting, by the peer WTRU, to or receiving from the source WTRU using the new source WTRU L2 ID, the new peer WTRU L2 ID, and the new session ID including the new MSB and the new LSB; wherein transmission by the peer WTRU to or reception from the source WTRU occurs in accordance with the new session ID, the new source WTRU L2 ID, and the new peer WTRU L2 ID while maintaining the session using the existing security context.

9. The peer WTRU of claim 8, wherein the peer WTRU receives the confirmation from the source WTRU while continuing to use the existing source WTRU L2ID, the existing peer WTRU L2ID, and the existing session ID.

10. The trigger event: A request for a new L2 ID from a higher layer or application layer, or The peer WTRU of claim 8 , wherein the step of changing the L2 ID comprises at least one of: receiving a request from the source WTRU to change the L2 ID.

11. The peer WTRU, receiving, from the source WTRU, the new source WTRU L2 ID and the new MSB of the new session ID using a message according to one of a keep-alive procedure, a privacy procedure, a PC5 link update procedure, or another communication procedure; The peer WTRU of claim 8 , configured to:

12. The peer WTRU of claim 8, wherein the session ID is a security context ID.

13. The peer WTRU of claim 8, wherein the peer WTRU communicates with the source WTRU over a PC5 link.

14. A non-transitory computer-readable storage medium containing instructions that, when executed by a computer, cause the computer to perform a method for use in an ongoing communications session, the method comprising: transmitting to or receiving from a peer wireless transmit / receive unit (WTRU) using an existing source WTRU Layer 2 identifier (L2ID), an existing peer WTRU L2ID, and an existing session identifier (ID) used for a session having an existing security context; Provided that said session is in progress and a trigger event occurs, receiving a new source WTRU L2 ID and new 8 most significant bits (MSBs) of a new session ID from the source WTRU; generating, by the peer WTRU, a new peer WTRU L2 ID and new 8 least significant bits (LSBs) of the new session ID; sending, by the peer WTRU, the new peer WTRU L2 and the new LSB of the new session ID to the source WTRU; receiving a confirmation of the new peer WTRU L2 ID and the new LSB of the new session ID from the source WTRU; transmitting, by the peer WTRU, to or receiving from the source WTRU using the new source WTRU L2 ID, the new peer WTRU L2 ID, and the new session ID including the new MSB and the new LSB; wherein transmitting to or receiving from the source WTRU occurs according to the new session ID, the new source WTRU L2 ID, and the new peer WTRU L2 ID while maintaining the session using the existing security context.

15. The non-transitory computer-readable storage medium of claim 14, wherein receiving confirmation from the source WTRU of the new peer WTRU L2ID and the new LSB of the new session ID comprises receiving the confirmation while continuing to use the existing source WTRU L2ID, the existing peer WTRU L2ID, and the existing session ID.

16. The non-transitory computer-readable storage medium of claim 14, wherein the new source WTRU L2ID, the new peer WTRU L2ID, and the new session ID are encrypted using the existing security context.

17. The non-transitory computer-readable storage medium of claim 14, wherein receiving by the peer WTRU a new source WTRU L2 ID and a new MSB of a new session ID includes receiving a message according to one of a keep-alive procedure, a privacy procedure, a PC5 link update procedure, or another communication procedure.

18. The condition that the session is in progress and a trigger event occurs is satisfied when the session is in progress, and A condition where a higher layer or application layer requests a new L2 ID, or The non-transitory computer-readable storage medium of claim 14 , wherein the conditions include any of the following: the peer WTRU receives a request from the source WTRU to change its L2 ID.

19. The non-transitory computer-readable storage medium of claim 14, wherein the session ID is a security context ID.

20. The non-transitory computer-readable storage medium of claim 14, wherein transmitting to or receiving from a peer WTRU includes communicating over a PC5 link.

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