Sidelink Operation Methodology for Beam-Based Mode 2 SL TCI Adaptation in Shared Spectrum

Abstract

A WTRU may be configured to receive configuration information comprising a enabled sidelink (SL) secondary transmission configuration indicator (S-TCI) mode indicator. The WTRU may receive first-stage SL control information (SCI) indicating one or more SL primary transmission configuration indicators (SL P-TCIs). The WTRU may determine whether to disable an SL S-TCI mode indicator for a second-stage SCI based on channel uncertainty. The WTRU may receive the second-stage SCI. In response to the SL S-TCI indicator remaining enabled for the second-stage SCI, the WTRU may determine one or more SL S-TCIs using the second-stage SCI. The WTRU may receive a physical sidelink shared channel (PSSCH) transmission using one or more SL P-TCIs and / or one or more SL S-TCIs based on the SL S-TCI mode indicator being enabled for the second-stage SCI.

Description

[Technical Field]

[0001] This application relates to a method of sidelink operation for beam-based Mode 2 SL TCI adaptation in a shared spectrum. [Background technology]

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Patent Application No. 63 / 413,449, filed October 5, 2022, the entire contents of which are incorporated herein by reference.

[0003] New Radio Vehicle-to-Everything (NR V2X) can be designed with a broader set of more advanced V2X use cases. NR V2X can be broadly organized into four use case groups: vehicle platooning, extended sensors, advanced driving, and remote driving.

[0004] Vehicle platooning may enable vehicles to dynamically form a group as they travel together. All vehicles in the group receive information from the lead vehicle to manage the group. Information from the lead vehicle allows the vehicles to move closer together than usual and to operate in a cooperative manner (e.g., going in the same direction and traveling together).

[0005] Augmented sensors may enable the exchange of raw or processed data collected through local sensors, live video images between vehicles, road site units, pedestrian devices, and / or V2X application servers. Vehicles may increase their awareness of their environment beyond what their own sensors can detect. Vehicles may have a wider and more holistic view of the local situation. A key characteristic of extended sensors is high data rate.

[0006] Advanced driving may enable semi-automated and / or fully automated driving. Each vehicle and / or roadside unit (RSU) may share its own perception data obtained from its local sensors with nearby vehicles. This sharing of data may enable vehicles to synchronize and / or adjust their trajectories or maneuvers. Each vehicle may share its driving intent with nearby vehicles.

[0007] Remote driving may enable remote drivers and / or V2X applications to operate remote vehicles for passengers who cannot drive themselves and / or remote vehicles located in hazardous environments. With limited variability and / or predictable routes (e.g., public transportation), cloud computing-based driving may be used. Key requirements for remote driving may include high reliability and / or low latency. Summary of the Invention

[0008] A method for beam-based Mode 2 resource allocation in unlicensed spectrum and a sidelink (SL) transmission configuration indication (SL TCI) mechanism is proposed. In the following, TCI may also refer to transmission configuration indicator.

[0009] The WTRU performs beam and TCI adaptation (e.g., in a shared spectrum for increased reception opportunities, improved performance, and reduced signaling overhead). The WTRU may be pre-configured for TCI configuration. Depending on the channel uncertainty, the SL secondary TCI (S-TCI) mode indicator may be set appropriately. When the channel uncertainty is high, the SL S-TCI mode indicator in the first stage sidelink control information (SCI) may be set to "enabled." When the channel uncertainty is low, the SL S-TCI mode indicator in the first stage SCI may be set to "disabled."

[0010] The WTRU may be TCI indicated (e.g., via a Sidelink Medium Access Control Element (SL MAC CE)) to receive the first stage SCI and / or the second stage SCI. The WTRU may receive the first stage SCI and obtain the SL Primary TCI (SL P-TCI). If the SL S-TCI mode indicator is configured, the WTRU may further check the channel uncertainty. If the channel uncertainty is high, the SL S-TCI mode indicator is set to "enabled." If the channel uncertainty is low, the SL S-TCI mode indicator is set to "disabled."

[0011] The WTRU may receive the second-stage SCI to obtain additional TCI information. If the SL S-TCI mode indicator (in the first-stage SCI) indicates "enabled," the WTRU may check additional control fields and obtain additional TCI (e.g., SL S-TCI) in the second-stage SCI. The WTRU may receive the physical sidelink shared channel (PSSCH) using both the SL P-TCI and the SL S-TCI to increase reception opportunities and improve performance.

[0012] When the WTRU receives the first-stage SCI, the WTRU may check the SL S-TCI mode indicator in the control field of the first-stage SCI. If the SL S-TCI mode indicator (e.g., in the first-stage SCI) indicates "disabled," the additional control field for the SL S-TCI may not be present, and the WTRU may not acquire the SL S-TCI in the second-stage SCI. The WTRU may receive the PSSCH using the SL P-TCI (e.g., only the SL P-TCI) to reduce signaling overhead.

[0013] A method for beam-based Mode 2 resource allocation and SL TCI mechanism in unlicensed spectrum may be proposed. If the SL S-TCI mode indicator is not configured, the WTRU may not check the channel uncertainty. The additional control field for the SL S-TCI may not be present, and the WTRU may not acquire the SL S-TCI in the second stage SCI. The WTRU may receive the PSSCH using the SL P-TCI (e.g., only the SL P-TCI).

[0014] The WTRU may perform beam and / or TCI adaptation (e.g., in a shared spectrum to increase reception opportunities, improve performance, and / or reduce signaling overhead). The WTRU may be pre-configured for TCI configuration. Depending on the channel uncertainty, the SL S-TCI mode indicator may be set appropriately. If the channel uncertainty is high, the SL S-TCI mode indicator (during the first stage SCI) may be set to "enabled." If the channel uncertainty is low, the SL S-TCI mode indicator (during the first stage SCI) may be set to "disabled."

[0015] The WTRU may be indicated for TCI (e.g., via the SL MAC CE) to receive the first stage SCI and the second stage SCI. The WTRU may receive the first stage SCI and obtain the SL P-TCI. If the SL S-TCI mode indicator is configured, the WTRU may further check the channel uncertainty. If the channel uncertainty is high, the SL S-TCI mode indicator is set to "enabled." If the channel uncertainty is low, the SL S-TCI mode indicator is set to "disabled."

[0016] The WTRU may receive the second-stage SCI to obtain additional TCI information. If the SL S-TCI mode indicator (in the first-stage SCI) indicates "enabled," the WTRU may check additional control fields and obtain additional TCI (e.g., SL S-TCI in the second-stage SCI). The WTRU may receive the PSSCH using both the SL P-TCI and / or the SL S-TCI to increase reception opportunities and / or improve performance.

[0017] When the WTRU receives the first stage SCI, the WTRU may check the SL S-TCI mode indicator in the control field of the first stage SCI.

[0018] If the SL S-TCI mode indicator (e.g., in the first stage SCI) indicates "disabled," the additional control field for the SL S-TCI may not be present and the WTRU may not acquire the SL S-TCI in the second stage SCI. The WTRU may receive the PSSCH using the SL P-TCI (e.g., only the SL P-TCI) to reduce signaling overhead.

[0019] If the SL S-TCI mode indicator is not configured, the WTRU may not check the channel uncertainty. The additional control field for the SL S-TCI may not be present, and the WTRU may not acquire the SL S-TCI in the second stage SCI. The WTRU may receive the PSSCH using the SL P-TCI (e.g., only the SL P-TCI).

[0020] The WTRU may be configured to receive configuration information comprising an enabled SL S-TCI mode indicator. The WTRU may receive first-stage SL control information (SCI) indicating one or more SL P-TCIs. The WTRU may determine whether to disable the SL S-TCI mode indicator for the second-stage SCI based on channel uncertainty. The WTRU may receive the second-stage SCI. In response to the SL S-TCI indicator remaining enabled for the second-stage SCI, the WTRU may determine one or more SL S-TCIs using the second-stage SCI. The WTRU may receive a physical sidelink shared channel (PSSCH) transmission using one or more SL P-TCIs and / or one or more SL S-TCIs based on the SL S-TCI mode indicator being enabled for the second-stage SCI.

[0021] The WTRU may determine channel uncertainty based on one or more channel uncertainty measurements. The WTRU may determine that channel uncertainty is high based on one or more channel uncertainty measurements being greater than a predetermined threshold. The WTRU may enable the SL S-TCI mode indicator based on determining that channel uncertainty is high. The WTRU may disable the SL S-TCI mode indicator based on determining that channel uncertainty is low.

[0022] The WTRU may include one or more of the following: the number of listen-before-talk (LBT) failures, the ratio of LBT failures to total measurements, the ratio of LBT failures to successes, the ratio of negative acknowledgements (NACKs) to positive acknowledgements (ACKs), the NACK percentage, the channel busy ratio (CBR), and / or the interference level. One or more SL S-TCIs are determined based on a control field in the second-stage SCI. The second-stage SCI may be received using the SL P-TCI. The WTRU may receive an SL MAC CE indicating the SL TCI to be used to receive the first-stage SCI and / or the second-stage SCI. [Brief explanation of the drawings]

[0023] [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 exemplary wireless transmit / receive unit (WTRU) that may 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 may be used within the communication system shown in FIG. 1A, according to one embodiment. [Figure 1D] FIG. 1B is a system diagram illustrating a further exemplary RAN and a further exemplary CN that may be used within the communication system shown in FIG. 1A, according to one embodiment. [Figure 2] FIG. 1 illustrates exemplary 5G Vehicle-to-Everything (V2X) versus Long Term Evolution Vehicle-to-Vehicle (LTE V2V) requirements. [Figure 3] 1 is a flowchart illustrating an example method for sidelink (SL) two-stage sidelink control information (SCI) based transmission configuration indication (TCI) indication. [Figure 4] 10 is a flowchart illustrating another exemplary method for sidelink two-stage SCI based TCI indication. [Figure 5] 10 is a flowchart illustrating an example method for sidelink two-stage SCI based TCI indication (configurable SL secondary TCI (SL S-TCI) mode indicator). [Figure 6] 1 is a flowchart illustrating an exemplary method for TCI adaptation. [Figure 7] FIG. 10 illustrates an example scenario for a physical sidelink shared channel (PSSCH) multiplexed with a second SCI in the frequency domain and a second SCI multiplexed with the PSSCH in the time domain. [Figure 8]FIG. 10 illustrates another exemplary scenario for a PSSCH multiplexed with a second SCI in the frequency domain and a second SCI multiplexed with a PSSCH in the time domain. [Figure 9] FIG. 10 illustrates an example scenario for a second SCI multiplexed with a PSSCH in the time domain. [Figure 10] FIG. 10 illustrates an example scenario for a second SCI multiplexed with a PSSCH in the frequency domain. [Figure 11] 4 is a flowchart illustrating an exemplary method for determining channel uncertainty. [Figure 12] 5 is a flowchart illustrating another exemplary method for determining channel uncertainty. [Figure 13] 1 is a flowchart illustrating an exemplary method for TCI adaptation. [Figure 14] 10 is a flowchart illustrating another exemplary method for TCI adaptation. DETAILED DESCRIPTION OF THE INVENTION

[0024] 1A illustrates an example communication system 100 in which one or more disclosed embodiments may be implemented. The communication system 100 may be a multiple-access system that provides content, such as voice, data, video, messaging, broadcasts, etc., 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 methods, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single-carrier FDMA (SC-FDMA), zero-tailed unique word DFT spread OFDM (ZT UW DTS-s OFDM), unique word OFDM (UW-OFDM), resource block-filtered OFDM, filter bank multicarrier (FBMC), etc.

[0025] 1A, communications system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, RANs 104 / 113, CNs 106 / 115, public switched telephone network (PSTN) 108, the Internet 110, and other networks 112, although it will be appreciated 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 include user equipment (UE), mobile stations, fixed or mobile subscriber units, subscription-based units, pagers, cellular phones, personal digital assistants (PDAs), smartphones, laptops, netbooks, personal computers, wireless sensors, hotspots or Mi-Fi devices, Internet of Things (IoT) devices, watches or other wearables, head-mounted displays (HMDs), vehicles, drones, medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in industrial and / or automated processing chain contexts), consumer electronics devices, devices operating on commercial and / or industrial wireless networks, etc. Any of the WTRUs 102a, 102b, 102c, and 102d may be referred to interchangeably as a UE.

[0026] 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 eNodeB, a Home Node B, a Home eNodeB, 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 appreciated that the base stations 114a, 114b may include any number of interconnected base stations and / or network elements.

[0027] 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, sometimes referred to as a cell (not shown). These frequencies may be in the licensed spectrum, the unlicensed spectrum, or a combination of the licensed and unlicensed spectrum. A cell may provide coverage for wireless services in 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 per sector of the cell. For example, beamforming may be used to transmit and / or receive signals in desired spatial directions.

[0028] The base stations 114a, 114b may communicate with one or more of the WTRUs 102a, 102b, 102c, 102d over an air interface 116, which may be any suitable wireless communications link (e.g., radio frequency (RF), microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet (UV), visible light, etc.). The air interface 116 may be established using any suitable radio access technology (RAT).

[0029] More particularly, 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 in 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 may include communications protocols such as High Speed ​​Packet Access (HSPA) and / or Evolved HSPA (HSPA+). HSPA may include High Speed ​​Downlink (DL) Packet Access (HSDPA) and / or High Speed ​​UL Packet Access (HSUPA).

[0030] 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).

[0031] In one embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as New Radio (NR) radio access, which may establish the air interface 116 using NR.

[0032] 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 and NR radio access, for example, 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).

[0033] 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, CDMA2000 EV-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.

[0034] 1A may be, for example, a wireless router, a Home NodeB, a Home eNodeB, or an access point and may utilize any suitable RAT to facilitate wireless connectivity in a local area, such as a workplace, a home, a vehicle, a premises, 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 utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.) to establish a picocell or femtocell. 1A, the base station 114b may have a direct connection to the Internet 110. Therefore, the base station 114b may not need to access the Internet 110 via the CN 106 / 115.

[0035] The RAN 104 / 113 may be in communication with the CN 106 / 115, which may be any type of network configured to provide voice, data, application, and / or Voice over Internet Protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. The data may have varying Quality of Service (QoS) requirements, such as different throughput, latency, error resilience, reliability, data throughput, mobility, 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 appreciated that the RAN 104 / 113 and / or the CN 106 / 115 may be in direct or indirect communication with other RANs employing 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 be in communication with another RAN (not shown) that employs GSM, UMTS, CDMA2000, WiMAX, E-UTRA, or WiFi radio technology.

[0036] 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 that provides 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) in 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 that may employ the same RAT as the RAN 104 / 113 or a different RAT.

[0037] 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 that may employ a cellular-based wireless technology and with a base station 114b that may employ an IEEE 802.11 wireless technology.

[0038] 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 appreciated that the WTRU 102 may include any sub-combination of the above elements while remaining consistent with an embodiment.

[0039] 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, it will be appreciated that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip.

[0040] The transmit / receive element 122 may be configured to transmit signals to and receive signals from a base station (e.g., base station 114a) over the air interface 116. For example, in one embodiment, the transmit / receive element 122 may be an antenna configured to transmit and / or receive RF signals. In one embodiment, the transmit / receive element 122 may be an emitter / detector configured to transmit and / or receive IR, UV, or visible light signals, for example. In yet another embodiment, the transmit / receive element 122 may be configured to transmit and / or receive both RF and light signals. It will be appreciated that the transmit / receive element 122 may be configured to transmit and / or receive any combination of wireless signals.

[0041] 1B as a single element, the WTRU 102 may include any number of transmit / receive elements 122. More particularly, 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.

[0042] The transceiver 120 may be configured to modulate signals to be 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.

[0043] 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 on a server or home computer (not shown).

[0044] The processor 118 may receive power from the power source 134 and may be configured to distribute and / or control power to other components in the WTRU 102. The power source 134 may be any suitable device for powering the WTRU 102. For example, the power source 134 may include one or more dry cell batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel-metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, etc.

[0045] 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 receive location information from base stations (e.g., base stations 114a, 114b) over the air interface 116 and / or determine its location based on the timing of signals being received from two or more nearby base stations. It will be appreciated that the WTRU 102 may acquire location information by way of any suitable location determination method while remaining consistent with an embodiment.

[0046] The processor 118 may further be coupled to other peripherals 138, which may include one or more software and / or hardware modules that provide additional features, functionality, and / or wired or wireless connectivity. For example, the peripherals 138 may include an accelerometer, an e-compass, a satellite transceiver, a digital camera (for photos and / or videos), a universal serial bus (USB) port, a vibration device, a television transceiver, a hands-free headset, a Bluetooth module, a frequency modulation (FM) radio unit, a digital music player, a media player, a video game player module, an internet browser, a virtual reality and / or augmented reality (VR / AR) device, an activity tracker, 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, an orientation 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.

[0047] The WTRU 102 may include a full-duplex radio in which transmission and reception of some or all of the signals (associated with a particular subframe for both the UL (e.g., for transmission) and the downlink (e.g., for reception)) may be parallel and / or simultaneous. The full-duplex radio may include an interference management unit 139 to reduce or substantially eliminate self-interference through either hardware (e.g., chokes) or signal processing via a processor (e.g., a separate processor (not shown) or via processor 118). In one embodiment, the WTRU 102 may include a half-duplex radio for transmission and reception of some or all of the signals (associated with a particular subframe for either the UL (e.g., for transmission) or the downlink (e.g., for reception)).

[0048] 1C is a system diagram illustrating the RAN 104 and the CN 106, according to one embodiment. As noted above, the RAN 104 may employ E-UTRA radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 104 may also be in communication with the CN 106.

[0049] The RAN 104 may include eNodeBs 160a, 160b, 160c, although it will be appreciated that the RAN 104 may include any number of eNodeBs while remaining consistent with an embodiment. The eNodeBs 160a, 160b, 160c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In one embodiment, the eNodeBs 160a, 160b, 160c may implement MIMO technology. Thus, the eNodeB 160a, for example, may use multiple antennas to transmit wireless signals to and / or receive wireless signals from the WTRU 102a.

[0050] Each of the eNodeBs 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 eNodeBs 160a, 160b, 160c may communicate with one another via an X2 interface.

[0051] 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 above elements is shown as part of the CN 106, it will be appreciated that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0052] The MME 162 may be connected to each of the eNodeBs 162a, 162b, 162c in the RAN 104 via an S1 interface and may act 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 attach 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 employ other radio technologies such as GSM and / or WCDMA.

[0053] The SGW 164 may be connected to each of the eNodeBs 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 handovers between eNodeBs, triggering paging when DL data is available for the WTRUs 102a, 102b, 102c, managing and storing the context of the WTRUs 102a, 102b, 102c, etc.

[0054] The SGW 164 may be connected to a PGW 166 that 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.

[0055] The CN 106 may facilitate communication 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 communication between the WTRUs 102a, 102b, 102c and traditional fixed communication devices. For example, the CN 106 may include or communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that acts 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.

[0056] Although the WTRU is depicted in FIGS. 1A-1D as a wireless terminal, in some representative embodiments that such a terminal may use (e.g., temporarily or permanently), it is considered that wired communications interface with the communications network.

[0057] In a representative embodiment, the other network 112 may be a WLAN.

[0058] 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 to or interface with a distribution system (DS) or another type of wired / wireless network that carries traffic into and out of the BSS. Traffic to a STA originating from outside the BSS may arrive through the AP and be sent to the STA. Traffic originating from a STA to a destination outside the BSS may be sent to the AP for delivery to the respective destination. Traffic between STAs within a BSS may be sent through the AP, e.g., where a source STA may send traffic to the AP, and the AP may send 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 sent between (e.g., directly between) a source STA and a destination STA using direct link setup (DLS). In some representative embodiments, the DLS may use 802.11e DLS or 802.11z tunneled DLS (TDLS). A WLAN using an Independent BSS (IBSS) mode may not have an AP, and the STAs within or using the IBSS (e.g., all of the STAs) may communicate directly with each other. The IBSS communication mode is sometimes referred to herein as an "ad hoc" communication mode.

[0059] When using the 802.11ac infrastructure mode of 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 20 MHz wide 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 some representative embodiments, carrier sense multiple access with collision avoidance (CSMA / CA) may be implemented, for example, in an 802.11 system. In CSMA / CA, STAs (e.g., every STA), including the AP, may sense the primary channel. If the primary channel is sensed / detected by a particular STA and / or determined to be busy, the particular STA may back off. One STA (e.g., only one station) may transmit at any given time in a given BSS.

[0060] A high-throughput (HT) STA may use a 40 MHz wide channel for communication, for example, via a combination of a primary 20 MHz channel with adjacent or non-adjacent 20 MHz channels to form a 40 MHz wide channel.

[0061] A very high throughput (VHT) STA may support 20 MHz, 40 MHz, 80 MHz, and / or 160 MHz wide channels. 40 MHz and / or 80 MHz channels may be formed by combining contiguous 20 MHz channels. A 160 MHz channel may be formed by combining eight contiguous 20 MHz channels or by combining two non-contiguous 80 MHz channels, sometimes referred to as an 80+80 configuration. In the 80+80 configuration, after channel encoding, the data may be passed through a segment parser that may split the data into two streams. Inverse fast Fourier transform (IFFT) processing and time-domain processing may be performed separately on each stream. The streams may be mapped onto two 80 MHz channels, and the data may be transmitted by the transmitting STA. At the receiver of the receiving STA, the operations described above for the 80+80 configuration may be reversed, and the combined data may be sent to the medium access control (MAC).

[0062] Sub-1 GHz operating modes are supported by 802.11af and 802.11ah. 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 may support meter-type control / machine-type communications, such as MTC devices, in macro coverage areas. MTC devices may have limited capabilities, including, for example, support for some and / or limited bandwidths (e.g., only support for some). MTC devices may include batteries with above-threshold battery life (e.g., to maintain very long battery life).

[0063] 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 may be designated as a primary channel. The primary channel may have a bandwidth equal to the largest common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel may be set and / or limited by the STA that supports the smallest bandwidth operating mode among all STAs operating in the BSS. In an 802.11ah example, the primary channel may be 1 MHz wide for a STA (e.g., an MTC-type device) that supports (e.g., only supports) the 1 MHz mode, even if the AP and other STAs in the BSS support 2 MHz, 4 MHz, 8 MHz, 16 MHz, and / or other channel bandwidth operating modes. Carrier sensing and / or network allocation vector (NAV) setting may depend on the status of the primary channel. For example, if the primary channel is busy for a STA (which may, for example, only support a 1 MHz mode of operation), it may be considered busy to transmit the entire available frequency band to the AP, even though most of the frequency band may remain idle and available for use.

[0064] In the United States, the available frequency bands that can be used by 802.11ah are from 902 MHz to 928 MHz. In South Korea, the available frequency bands are from 917.5 MHz to 923.5 MHz. In Japan, the available frequency bands are from 916.5 MHz to 927.5 MHz. The total available bandwidth for 802.11ah is 6 MHz to 26 MHz depending on the country code.

[0065] 1D is a system diagram illustrating the RAN 113 and the CN 115, according to one embodiment. As mentioned above, the RAN 113 may employ NR radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 113 may also be in communication with the CN 115.

[0066] The RAN 113 may include gNBs 180a, 180b, and 180c, although it will be appreciated 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 use multiple antennas to transmit wireless signals to and / or receive wireless signals from, for example, 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 an unlicensed spectrum, while the remaining component carriers may be on a 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).

[0067] The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using scalable numerology-related transmissions. 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., including various numbers of OFDM symbols and / or lasting for varying lengths of absolute time).

[0068] The gNBs 180a, 180b, 180c may be configured to communicate with the WTRUs 102a, 102b, 102c in a standalone configuration and / or a non-standalone configuration. In a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c without accessing another RAN (e.g., eNodeBs 160a, 160b, 160c, etc.). In a standalone configuration, the WTRUs 102a, 102b, 102c may utilize one or more of the gNBs 180a, 180b, 180c as mobility anchor points. In a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using signals in unlicensed bands. In a non-standalone configuration, the WTRUs 102a, 102b, 102c may communicate with / connect to a gNB 180a, 180b, 180c while also communicating with / connecting to another RAN, such as an eNodeB 160a, 160b, 160c. For example, the WTRUs 102a, 102b, 102c may implement DC principles to communicate with one or more gNBs 180a, 180b, 180c and one or more eNodeBs 160a, 160b, 160c substantially simultaneously. In a non-standalone configuration, the eNodeBs 160a, 160b, 160c may act as mobility anchors 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.

[0069] 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 towards user plane functions (UPFs) 184a, 184b, routing of control plane information towards access and mobility management functions (AMFs) 182a, 182b, etc. As shown in FIG. 1D, the gNBs 180a, 180b, 180c may communicate with one another via an Xn interface.

[0070] 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 above elements is shown as part of the CN 115, it will be appreciated that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0071] The AMF 182a, 182b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via an N2 interface and may act as a control node. For example, the AMF 182a, 182b may be responsible for 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, managing registration areas, terminating NAS signaling, mobility management, etc. Network slicing may be used by the AMF 182a, 182b to customize the CN support of the WTRUs 102a, 102b, 102c based on the type of service being utilized by the WTRUs 102a, 102b, 102c. For example, different network slices may be established for different use cases, such as services relying on highly 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 employ other radio technologies, such as LTE, LTE-A, LTE-A Pro, and / or non-3GPP access technologies, such as WiFi.

[0072] 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 allocating UE IP addresses, managing PDU sessions, controlling policy enforcement and QoS, providing downlink data notifications, etc. The type of PDU session may be IP-based, non-IP-based, Ethernet-based, etc.

[0073] The UPFs 184a, 184b may be connected to one or more of the 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 communication 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 policies, supporting multi-homed PDU sessions, handling user plane QoS, buffering downlink packets, providing mobility anchoring, etc.

[0074] 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 be connected to the local data networks (DNs) 185a, 185b through 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.

[0075] 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, eNodeBs 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 devices 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, the emulation devices may be used to test other devices and / or simulate network and / or WTRU functionality.

[0076] The emulation device may be designed to perform one or more tests of other devices in a lab environment and / or an operator network environment. For example, one or more emulation devices may perform one or more or all functions while fully or partially implemented and / or deployed as part of a wired and / or wireless communications network to test other devices in the communications network. One or more emulation devices may perform one or more or all functions while temporarily implemented / deployed as part of a wired and / or wireless communications network. The emulation device may be directly coupled to another device for testing purposes and / or may perform testing using over-the-air wireless communications.

[0077] The one or more emulation devices may perform one or more functions, inclusive, without being implemented / deployed as part of a wired and / or wireless communications network. For example, the emulation devices may be utilized in a test laboratory and / or in a test scenario in an undeployed (e.g., test) wired and / or wireless communications network to implement testing of one or more components. The one or more emulation devices may be test equipment. Direct radio frequency (RF) coupling and / or wireless communication via RF circuitry (which may include, e.g., one or more antennas) may be used by the emulation devices to transmit and / or receive data.

[0078] FIG. 2 is a diagram of 5G vehicle-to-everything (V2X) versus Long Term Evolution vehicle-to-vehicle (LTE V2V) requirements. Depicted in FIG. 2 is a representation of the most stringent requirements for 5G V2X (as opposed to the requirements for LTE V2V), which may include a maximum sidelink range of 1000 m at 204, a maximum throughput of 1.0 Gbps at 208, a minimum latency of 3.0 ms at 212, a maximum reliability of 99.999% at 216, and / or a maximum transmission rate of 100 messages / s. Other challenging requirements may also include mobility relative velocity, which may have a maximum of 550 km / h at 220 and / or a positioning accuracy that may be as small as about 0.1 m at 224. No use case may require all of these boundary requirements alone. Further requirements may include security, integrity, authorization, and / or privacy.

[0079] New Radio Vehicle-to-Everything NR V2X has physical layer support for broadcast, unicast, and / or groupcast sidelink operation. The addition of unicast and / or groupcast can be linked with the introduction of sidelink Hybrid Automatic Repeat Request (HARQ) feedback, higher-order modulation, sidelink Channel State Information (CSI), and / or PC5-Radio Resource Control (RRC), etc.

[0080] The NR V2X sidelink may use one or more physical channels and / or signals, including the Physical Sidelink Broadcast Channel (PSBCH) and its Demodulation Reference Signal (DMRS), the Physical Sidelink Control Channel (PSCCH) and its DMRS, the Physical Sidelink Shared Channel (PSSCH) and its DMRS, the Physical Sidelink Feedback Channel (PSFCH), and / or the Sidelink Primary and Secondary Synchronization Signals (S-PSS and / or S-SSS), which, together with the PSBCH, may be organized into a Sidelink Synchronization Signal Block (S-SSB). The S-PSS and S-SSS are sometimes referred to together as Sidelink Synchronization Signals (SLSS), Phase Tracking Reference Signals in FR2 (PT-RS), and / or Channel State Information Reference Signals (CSI-RS).

[0081] The NR-V2X sidelink may support subcarrier spacings of 15, 30, 60, and / or 120 kHz. These subcarrier spacings may be associated with cyclic prefix (CP) and frequency ranges for the NR uplink / downlink (UL / DL), but using a cyclic prefix orthogonal frequency division multiplexing (CFM) waveform (e.g., only a CFM waveform). Available modulation schemes may include quadrature phase shift keying (QPSK), 16 quadrature amplitude modulation (QAM), 64 QAM, and / or 256 QAM.

[0082] The PSBCH may transmit the Sidelink Broadcast Channel (SL-BCH) transport channel carrying the Sidelink V2X Master Information Block (MIB-V2X) from the RRC layer. The PSBCH may transmit the Master Information Block (MIB)-V2X every 160 ms in 11 RBs of the SL bandwidth with possible repetition in the period. The DMRS associated with the PSBCH may be transmitted in every symbol of the S-SSB slot. The S-PSS and S-SSS may be transmitted together with the PSBCH in the S-SSB. They jointly carry the SLSS ID used by the WTRU.

[0083] Sidelink control information (SCI) in NR V2X may be transmitted in two stages: The PSCCH carries the first-stage SCI and may include information (e.g., for enabling sensing operations and / or information regarding PSSCH resource allocation).

[0084] The PSSCH may transmit the second-stage SCI and / or the SL-SCH transport channel. The second-stage SCI may carry information (e.g., information needed to identify and / or decode the associated SL-SCH, as well as control for HARQ procedures and / or triggers for CSI feedback, etc.). The SL-SCH may carry transport blocks (TBs) of data for transmission over the SL.

[0085] The gNB may schedule or configure resources on which the PSSCH may be transmitted. The transmitting WTRU may determine the resources for the PSSCH through a sensing procedure performed autonomously by the WTRU. A given transport block (TB) may be transmitted multiple times. The DMRS associated with the rank-1 and / or rank-2 PSSCH may be transmitted in two, three, or four sidelink symbols distributed throughout the sidelink slot. Multiplexing between the PSCCH and / or PSSCH may be time and frequency within a slot.

[0086] The PSFCH may carry HARQ feedback over the sidelink from the WTRU. The WTRU may be the intended recipient of the PSSCH transmission. The WTRU that is the intended recipient of the transmission will be referred to as the Rx WTRU, and the WTRU that performed the transmission will be referred to as the Tx WTRU. The sidelink HARQ feedback may be in the form of traditional positive and / or negative acknowledgements (ACK / NACK) and / or NACK only, where nothing is transmitted in case of successful decoding. The PSFCH transmits a Zadoff-Chu sequence in one PRB repeated across two OFDM symbols. The first OFDM symbol may be used for AGC near the end of the sidelink resources in the slot. The time resource for the PSFCH may be preconfigured to occur once every one, two, or four slots.

[0087] Mode 1 is for resource allocation by the gNB. NR V2X may generate a diverse array of periodic and / or aperiodic message types. Thus, resource allocation Mode 1 may provide dynamic sidelink resource grants from the gNB and / or periodic sidelink resource grants configured semi-statically by RRC.

[0088] The dynamic sidelink grant downlink control information (DCI) may grant resources for one or more transmissions of a transport block, allowing for reliability control. If HARQ procedures are enabled, one or more transmissions may be subject to a sidelink HARQ procedure.

[0089] A sidelink configured grant may be configured once and used by the WTRU (e.g., immediately), e.g., until RRC signaling known as Type 1 releases the sidelink configured grant. The WTRU may be enabled to continue using this type of sidelink configured grant when a beam failure or physical layer problem occurs during an NR Uu until a radio link failure (RLF) detection timer expires before falling back to an exception resource pool. Another type of sidelink configured grant, known as Type 2, may be configured once but may not be used until (e.g., only until) the gNB sends a DCI to the WTRU indicating that the sidelink configured grant is currently active and another DCI indicates deactivation. Both Type 1 and / or Type 2 resources may be a rotating set of sidelink resources that the gNB would like to match the characteristics of V2X traffic. Multiple configured grants may be configured to enable provisioning for different services (e.g., traffic types, etc.).

[0090] MCS information for dynamic configured grants may be provided and / or constrained by RRC signaling instead of traditional DCI. RRC may configure the exact MCS and / or range of MCSs that the Tx WTRU uses. The MCS may also be left unconfigured. In some examples, if RRC does not provide the exact MCS, the Tx WTRU may be left to select an appropriate MCS itself. The Tx WTRU may be left to select an appropriate MCS based on knowledge it has of the TB to be transmitted and / or of the sidelink radio conditions.

[0091] Mode 2 may be for WTRU autonomous resource selection. The basic structure of Mode 2 may be to select an appropriate amount of unused resources for its own transmission, those that the WTRU detects, those in a preconfigured resource pool, resources not used by other WTRUs with higher priority traffic, and / or resources that it detects. The WTRU may transmit and / or retransmit the selected resources a certain number of times and / or until a reason for resource reselection is triggered.

[0092] The Mode 2 detection procedure may select and reserve resources for various purposes (e.g., to reflect that NR V2X introduces sidelink HARQ supporting unicast and groupcast in the physical layer). Mode 2 may reserve resources to be used for blind retransmissions and / or HARQ feedback-based retransmissions of some transport blocks. When Mode 2 reserves resources for blind retransmissions or HARQ feedback-based retransmissions of some transport blocks, the resources may be indicated in the SCI scheduling the transport block. Additionally or alternatively, Mode 2 may select resources to be used for the first transmission of a later transport block. When Mode 2 selects resources to be used for the first transmission of a later transport block, the resources may be indicated in the SCI scheduling the current transport block. The first transmission of the transport block may be performed after detection and / or resource selection but without reservation.

[0093] The first stage SCI transmitted by the WTRU on the PSCCH may indicate the time-frequency resources on which the WTRU may transmit the PSSCH. These SCI transmissions may be used by detecting WTRUs and / or by maintaining a record of which resources other WTRUs have recently reserved.

[0094] The detecting WTRU may then select resources for its retransmission from within the resource selection window. The window may start shortly after the trigger for resource reselection. The window may not be longer than the remaining latency budget of the packet to be transmitted. Reserved resources in the selection window with SL-RSRP above a threshold may be eliminated from being candidates by the detecting WTRU, with the threshold set according to the priority of the detecting and transmitting WTRU's traffic. Thus, a higher priority transmission from the detecting WTRU may occupy resources reserved by a transmitting WTRU with a sufficiently low SL-RSRP and sufficiently lower priority traffic.

[0095] A bandwidth portion (BWP) may be defined for the sidelink as well as for the UL / DL, providing a convenient way to specify aspects related to the WTRU's radio frequency (RF) hardware chain implementation. The WTRU may be configured with one active sidelink BWP when in connected mode to a gNB, which is the same as the single sidelink BWP used for idle mode or out-of-coverage operation.

[0096] The subcarrier spacing used on the sidelink may be given during sidelink BWP pre-configuration from the same set of values ​​and association to a frequency range (e.g., 15, 30, or 60 kHz for FR1 and 60 or 120 kHz for FR2) for the Uu interface. Thus, sidelink transmission and / or reception for the WTRU is contained within the sidelink BWP, and the same sidelink BWP may be used for both transmission and / or reception. This means that resource pools, S-SSBs, etc., also need to be contained within the appropriate sidelink BWP from the WTRU's perspective.

[0097] To support a wide range of services, 5G NR systems aim to be flexible enough to meet the connectivity requirements of a range of existing and future services in an efficient manner. For example, NR may support the potential use of frequency ranges up to 100 GHz.

[0098] The NR specifications developed in Rel-15 and Rel-16 define operation for frequencies up to 52.6 GHz, and all physical layer channels, signals, procedures, and / or protocols may be designed to be optimized for use below 52.6 GHz.

[0099] Frequencies above 52.6 GHz may face more difficult challenges (e.g., higher phase noise, greater propagation loss due to high atmospheric absorption, lower power amplifier efficiency, and / or stronger power spectral density regulatory requirements in unlicensed bands compared to lower frequency bands). Additionally or alternatively, the frequency range above 52.6 GHz may include larger spectrum allocations and larger bandwidths that may not be available for bands below 52.6 GHz.

[0100] As an initial effort to enable and / or optimize 3GPP NR systems for operation above 52.6 GHz, the 3GPP RAN studied the requirements for NR beyond 52.6 GHz. In particular, the 3GPP RAN studied requirements for NR up to 114.25 GHz, including global spectrum availability (including channelization and licensing regimes) and regulatory requirements, potential use cases and / or deployment scenarios, and / or design requirements and / or considerations for NR systems over regulatory requirements. Potential use cases identified in the study include high-data-rate enhanced mobile broadband (eMBB), mobile data offload, short-range high-data-rate device-to-device (D2D) communications, broadband distribution networks, integrated access backhaul (IAB), factory automation, industrial IoT (IIoT), wireless display transfer, augmented reality (AR) and / or virtual reality (VR) wearables, intelligent transportation systems (ITS) and V2X, data center rack-to-rack connectivity, smart grid automation, private networks, and / or support for high positioning accuracy. The use cases span several deployment scenarios beyond those identified in the study. Deployment scenarios include, but are not limited to, indoor hotspots, dense urban areas, urban micro, urban macro, rural areas, factory halls, and / or indoor D2D scenarios. The study also identified several system design requirements around waveform, multiple-input multiple-output (MIMO) operation, device power consumption, channelization, bandwidth, range, availability, connectivity, and / or spectrum regime considerations.

[0101] Frequencies of interest in the near term include frequencies between 52.6 GHz and 71 GHz due to their proximity to sub-52.6 GHz, where current NR systems may be optimized and / or there may be imminent opportunities for high data rate communications (e.g., licensed spectrum between 57 GHz and 71 GHz as well as unlicensed spectrum).

[0102] NR Rel-15 defined two frequency ranges for operation: frequency range FR1, which spans from 410 MHz to 7.125 GHz, and frequency range FR2, which spans from 24.25 GHz to 52.6 GHz.

[0103] The proximity of this frequency range (57-71 GHz) to FR2 and the imminent commercial opportunity for high data rate communications compel 3GPP to address NR operation in this frequency regime. To minimize the specification burden and maximize the leverage of FR2-based implementations, 3GPP decided to extend FR2 operation up to 71 GHz with the adoption of one or more new numerologies (e.g., larger subcarrier spacing). New numerologies can be identified through waveform studies for NR > 52.6 GHz.

[0104] The procedures defined in New Radio Unlicensed (NR-U) for operation in unlicensed spectrum may also be utilized for operation in the unlicensed 60 GHz band. NR operation may be supported up to 71 GHz, allowing for both licensed and / or unlicensed operation. Similar to regular NR and / or NR-U operation below 52.6 GHz, NR / NR-U operation from 52.6 GHz to 71 GHz may be standalone or aggregated via CA and / or DC with an anchor carrier.

[0105] In Rel-16 NR-U, the supported numerology (e.g., SCS) may be set as 15, 30, and 60 KHz, respectively. The listen-before-talk (LBT) bandwidth is set to 20 MHz in Rel-16 NR-U. Based on the minimum LBT bandwidth that needs to be supported, the first BWP in the DL is nominally 20 MHz for Rel-16 NR-U. The maximum supported channel bandwidth may be set to 100 MHz. The WTRU channel bandwidth (or activated BWP) may be set as an integer multiple of the LBT bandwidth (e.g., 20 MHz). For example, for an SCS equal to 30 KHz, the total allocated PRB numbers for bandwidths of 20 MHz, 40 MHz, and 80 MHz are equal to 48, 102, and 214, respectively.

[0106] Rel-18 may cover sidelink communications with FR1 unlicensed channel access (e.g., without beam management (BM)) for Mode 2 and FR2 licensed operation with BM. Unlicensed channel access and / or physical channel design (e.g., unlicensed channel access and / or physical channel design only) may be considered for FR1. BM (e.g., BM only) may be considered for licensed spectrum. Rel-18 does not consider FR2 unlicensed operation with BM. Rel-18 may consider unicast communication. Rel-18 may not consider other cast types.

[0107] In beam-based SL in unlicensed bands and / or shared spectrum, channel uncertainty may prevent a signal and / or channel from being transmitted in a certain spatial direction due to LBT failure. Even if a signal and / or channel can be transmitted in a certain spatial direction, the signal and / or channel may not be received due to interference (e.g., from a hidden node in a certain spatial direction). Therefore, unlicensed beam-based SL systems require a mechanism to increase transmission and / or reception opportunities. The unique two-stage control design in SL requires the incorporation of a transmission configuration indication (TCI) framework into SL to increase transmission and / or reception opportunities in the unlicensed spectrum. (Hereinafter, TCI may also refer to a transmission configuration indicator.) Beam-based unlicensed bands have additional dimensions in the spatial and / or frequency-time domains. Resource allocation in beam-based unlicensed bands may be affected by channel uncertainty and / or the spatial domain. For example, beam-based unlicensed spectrum and / or shared spectrum may require directional transmission and / or reception beams for resource allocation to handle channel uncertainty.

[0108] One or more methods of beam-based Mode 2 resource allocation and SL TCI mechanisms in the unlicensed spectrum may be provided. To optimize beam-based Mode 2 resource allocation, the Rx WTRU may create more reception opportunities. To optimize beam-based Mode 2 resource allocation, the Tx WTRU may create more transmission opportunities. An Rx beam for the Rx WTRU may be indicated in the TCI to support receive beamforming at the Rx. A Tx beam for the Tx WTRU may be indicated in the TCI to support transmit beamforming at the Tx WTRU. Two or more TCIs may be indicated for PSSCH reception or transmission. In an example, the WTRU may indicate a TCI in a first stage SCI, a second stage SCI, a joint SCI, and / or an additional TCI in the first stage SCI and / or the second stage SCI. Additionally or alternatively, the TCI bits may be split and carried and / or indicated in both the first stage SCI and / or the second stage SCI. In an example, the WTRU may indicate the TCI in a Medium Access Control Element (MAC CE) and / or in a joint SCI and MAC CE.

[0109] The TCI may be indicated in a first-stage SCI, a second-stage SCI, a PSSCH, a MAC CE, a PC5-RRC, a new SCI, etc., and / or a combination thereof. The TCI may be indicated using multiple methods (e.g., a two-stage approach, a multi-stage approach, a split approach, a joint approach, a one-stage approach, etc.). Utilizing a primary TCI may address channel uncertainty in an unlicensed spectrum. Introducing a secondary TCI may optimize system operation in an unlicensed spectrum. The use of a primary TCI and / or a secondary TCI may accommodate improved performance while reduced signaling overhead. Multiple TCIs described with respect to a primary TCI and / or a secondary TCI characterize multiple options for describing the relationship between different signals and / or channels (e.g., multiple TCIs for describing the relationship between a source signal and / or channel and a target signal and / or channel, and / or the relationship between a source signal and / or channel and a target signal and / or channel). For example, the multiple TCIs may also be described as a primary TCI, a secondary TCI, a tertiary TCI, ..., a kth TCI, etc.

[0110] In an example, in a hierarchical TCI (e.g., where the TCIs are organized in a hierarchy), a hierarchy of TCIs includes a superset of a subset of another hierarchy within the plurality of TCIs. For example, in the case of a spatial domain relationship, the plurality of TCIs may be defined according to the granularity (e.g., beam width) of a beam associated with a target signal and / or channel and the granularity (e.g., beam width) of a beam associated with a source signal and / or channel. For example, at a first level in the hierarchy, a beam associated with a target signal may be a beam of a first width, and a beam associated with a source signal and / or channel may also be a beam of a first width. At a second level in the hierarchy, a beam associated with a target signal may be a beam of a second width, and a beam associated with a source signal and / or channel may also be a beam of a second width, and so on. Note that a first width beam refers to a first width beam, a second width beam refers to a second width beam, and so on (e.g., the first TCI, the second TCI, the third TCI, ..., the kth TCI, etc.).

[0111] Hereinafter, terms such as primary versus secondary TCI, hierarchical TCI, or multiple TCIs comprising a first TCI, a second TCI, a third TCI, ..., a kth TCI, etc. may be used interchangeably. These interchangeable terms may refer to multiple TCI numberings that correspond to multiple options that can be configured or signaled to describe the relationship between a source signal and / or channel and a target signal and / or channel.

[0112] Both the primary TCI and the secondary TCI may be carried in the first-stage SCI. This solution may increase the reception opportunity for the Rx WTRU to receive the signal and / or channel (e.g., PSSCH). To reduce the signaling overhead of the first-stage SCI and enable TCI adaptation to channel uncertainty, one example considers using a two-stage TCI indication. The primary TCI may be carried in the first-stage SCI, and the secondary TCI may be carried in the second-stage SCI. Another example uses TCI bit splitting, where the TCI bits may be partitioned and / or divided. Some TCI bits may be carried in the first-stage SCI. Additional bits for the TCI may be carried in the second-stage SCI.

[0113] The Rx WTRU may use the first TCI to derive a suitable Rx beam for the second-stage SCI in the Tx WTRU in the Rx WTRU sidelink direction. Further, the Rx WTRU may derive a suitable Tx beam for the second-stage SCI in the Tx WTRU in the Rx WTRU sidelink direction. The Rx WTRU may use the second TCI to derive a suitable Rx beam for the PSSCH in the Tx WTRU in the Rx WTRU sidelink direction. Further, the Rx WTRU may derive a suitable Tx beam for the PSSCH in the Tx WTRU in the Rx WTRU sidelink direction.

[0114] To further optimize the adaptation procedure, the first-stage SCI may indicate whether a TCI control field is present and / or its location within the second-stage SCI. The first-stage SCI may also indicate an SCI format. For example, an existing SCI format with additional TCI control fields and / or a new SCI format that may include a TCI control field may be used. In these examples, one or more TCI control fields may be utilized.

[0115] For example, a new SCI format for the first stage SCI may be introduced to support TCI for shared spectrum or unlicensed beam based systems, and a new SCI format for the second stage SCI may be introduced to support TCI for shared spectrum and / or unlicensed beam based systems.

[0116] To support dynamic adaptation of TCI transmission opportunities for a shared spectrum, the number of primary and / or secondary TCIs may be based on the number of LBT failures, the number of NACKs, the ratio of ACKs to NACKs, etc. If the number of LBT failures increases and / or channel uncertainty is high, the number of secondary TCIs may increase. If the number of LBT failures decreases and / or channel uncertainty is low, the number of secondary TCIs may decrease.

[0117] Channel uncertainty may be measured based on the number of LBT failures, the percentage of LBT failures, the number of NACKs, the percentage of NACKs, the ratio of NACKs to ACKs, the interference level, and the like.

[0118] The number of secondary TCIs may be configured, reconfigured, dynamically indicated, and / or increased autonomously based on some conditions and / or some criteria (e.g., the number of secondary TCIs may increase implicitly as LBT failures increase).

[0119] The primary TCI and / or secondary TCI signaling may also be based on two-stage PC5 RRC and SL MAC CE or three-stage PC5 RRC, SL MAC CE, and / or SCI. For example, in two-stage PC5 RRC and SL MAC CE, the Rx WTRU may receive one or more TCIs through PC5 RRC signaling. The Rx WTRU may then receive one or more TCIs through MAC CE, where the one or more TCIs received through MAC CE are a subset of the one or more TCIs received by the Rx WTRU via PC5 RRC signaling.

[0120] For a three-stage PC5 RRC, SL MAC CE, and SCI approach to TCI signaling, the Rx WTRU may receive one or more TCIs through PC5 RRC signaling. The Rx WTRU may then receive one or more TCIs through the MAC CE, where the one or more TCIs received through the MAC CE are a subset of the one or more TCIs received by the Rx WTRU through PC5 RRC signaling. The Rx WTRU may receive one or more TCIs through the SCI, where the one or more TCIs received through the SCI are a subset of the one or more TCIs received by the Rx WTRU through the MAC CE and / or PC5 RRC signaling.

[0121] In two-stage PC5 RRC and SL MAC CE, the Tx WTRU may transmit one or more TCIs through PC5 RRC signaling, and then the Tx WTRU may transmit one or more TCIs through the MAC CE, where the one or more TCIs transmitted through the MAC CE are a subset of the one or more TCIs transmitted by the Tx WTRU via PC5 RRC signaling.

[0122] For a three-stage PC5 RRC, SL MAC CE, and SCI approach to TCI signaling, the Tx WTRU may transmit one or more TCIs through PC5 RRC signaling. The Tx WTRU may then transmit one or more TCIs through MAC CE, where the one or more TCIs transmitted through MAC CE are a subset of the one or more TCIs transmitted by the Tx WTRU via PC5 RRC signaling. The Tx WTRU may transmit one or more TCIs through SCI, where the one or more TCIs transmitted through SCI are a subset of the one or more TCIs transmitted by the Tx WTRU via MAC CE and / or PC5 RRC signaling. The number of configured, activated, and / or indicated TCIs may differ between the primary and / or secondary TCIs. The above-described examples are applicable to unicast links and may be extended to multiple unicast links.

[0123] 3 shows an example method 300 for sidelink two-stage SCI-based TCI indication. At 304, a WTRU may be pre-configured for TCI configuration. At 308, the WTRU may be indicated for TCI (e.g., via an SL MAC CE) to receive first-stage SCIs and / or second-stage SCIs. At 312, the WTRU may receive the first-stage SCI using the indicated TCI state (e.g., by the SL MAC CE) to obtain information about the primary TCI (SL P-TCI). At 316, the WTRU may receive the second-stage SCI and obtain additional TCI information (e.g., secondary SL TCI (SL S-TCI)) using the indicated TCI state (e.g., by the SL MAC CE). At 318, the WTRU may determine whether SL S-TCI mode is activated. The value of the SL S-TCI mode indicator may be 1 when the SL S-TCI mode is activated and 0 when the SL S-TCI mode is not activated.

[0124] The WTRU may acquire an SL S-TCI mode indicator in the first stage SCI. As shown at 320, if the value of the first stage SCI indicator is “1”, the WTRU may check the additional TCI control field and / or acquire the SL S-TCI in the second stage SCI. At 324, the WTRU may receive the PSSCH using both the SL P-TCI and the SL S-TCI. As shown at 328, if the value of the first stage SCI indicator is “0”, there is no additional control field for the SL S-TCI and / or the WTRU may not acquire the SL S-TCI in the second stage SCI. At 332, the WTRU may receive the PSSCH using the SL P-TCI (e.g., only the SL P-TCI).

[0125] 4 is another exemplary method of sidelink two-stage SCI-based TCI indication. Figure 4 shows the previously described SL P-TCI and SL S-TCI, which may also be included in the first-stage SCI. Additionally or alternatively, both the SL P-TCI and / or the SL S-TCI may also be included in the second-stage SCI.

[0126] At 404, the WTRU may be pre-configured with a TCI configuration and conditions for a TCI state. At 408, the WTRU may be indicated with a TCI to receive the first-stage SCI. Such a TCI indication may be via the SL MAC CE. The SL MAC CE may indicate the TCI for the Rx WTRU to receive the first-stage SCI.

[0127] At 412, the WTRU may receive the first-stage SCI and / or obtain TCI information, such as one or more SL P-TCIs, for receiving the second-stage SCI. At 416, the WTRU may receive the second-stage SCI using the indicated one or more SL P-TCIs in the first-stage SCI.

[0128] The WTRU may obtain the TCI information in the second-stage SCI and receive the PSSCH based on the SL S-TCI mode indicator. The WTRU may receive the PSSCH using the indicated SL P-TCI in the first-stage SCI and / or further using the indicated SL S-TCI in the second-stage SCI. For example, the WTRU may receive a data channel using a beam indicated by the SL P-TCI and the SL S-TCI. For example, the WTRU may receive a data channel using a beam indicated by the SL P-TCI and the SL S-TCI simultaneously.

[0129] The WTRU may check the first stage SCI whether the SL S-TCI mode indicator is activated. At 418, the WTRU may determine whether the SL S-TCI mode is activated. The value of the SL S-TCI mode indicator may be 1 when the SL S-TCI mode is activated and 0 when the SL S-TCI mode is not activated. At 420, if the SL S-TCI mode is activated and / or indicated, e.g., if the SL S-TCI indicator is '1', the WTRU may check additional control fields and / or obtain the SL S-TCI in the second stage SCI. At 424, the WTRU may receive the PSSCH using both the SL P-TCI and the SL S-TCI. At 428, if the SL S-TCI mode is not activated and indicated, e.g., if the SL S-TCI indicator is '0', no additional control field for the SL S-TCI is present. The WTRU may not acquire the SL S-TCI in the second stage SCI. At 432, the WTRU may receive the PSSCH using the SL P-TCI (eg, only the SL P-TCI).

[0130] For fast TCI adaptation, an SL S-TCI mode indicator may be included in the first-stage SCI to indicate whether the SL S-TCI control field is present. This may reduce overhead, but the TCI may be dynamically changed. Fast TCI adaptation implies that either the TCI state or the number of TCI states may be dynamically changed based on some criteria and / or channel conditions. In fast TCI adaptation, the TCI state may adapt to handle channel uncertainty. Both the TCI state and the number of TCI states may adapt dynamically and / or fast depending on the channel conditions and / or channel uncertainty.

[0131] In the example, depending on the value of the SL S-TCI mode indicator, if the SL S-TCI mode indicator is "1", the SL S-TCI control field is present in the second stage SCI, if the SL S-TCI mode indicator is "0", the SL S-TCI control field is not present or absent in the second stage SCI.

[0132] As described above, the first stage SCI may include both an SL P-TCI and / or an SL S-TCI. Additionally or alternatively, the second stage SCI may also include both an SL P-TCI and / or an SL S-TCI. The SL S-TCI mode indicator control field may be fixed and / or not configurable. The SL S-TCI mode indicator control field may always be present in the first stage SCI.

[0133] Additionally or alternatively, the SL S-TCI mode indicator control field may be configurable (e.g., by RRC and / or PC5 RRC). For example, PC5 RRC may configure the SL S-TCI mode indicator in the first stage SCI. If configured by RRC, the SL S-TCI mode indicator control field may be present in the first stage SCI. If not configured by RRC, the SL S-TCI mode indicator control field may be absent in the first stage SCI.

[0134] The SL S-TCI mode indicator control field may be present if configured by RRC and / or PC5 RRC. Whether the SL S-TCI control field is present may depend on the value of the SL S-TCI mode indicator. For example, if the SL S-TCI mode indicator is '1', the SL S-TCI control field may be present in the second stage SCI. If the SL S-TCI mode indicator is '0', the SL S-TCI control field may not be present and / or absent in the second stage SCI.

[0135] 5 shows an example method for sidelink two-stage SCI-based TCI indication using a configurable SL S-TCI mode indicator. At 504, a WTRU may be pre-configured with a TCI configuration. At 508, the WTRU may be indicated for a TCI to receive the first-stage SCI. The SL MAC CE may indicate a TCI for the Rx WTRU to receive the first-stage SCI. At 512, the WTRU may receive the first-stage SCI and / or obtain TCI information, such as one or more SL P-TCIs, to receive the second-stage SCI. At 516, the WTRU may receive the second-stage SCI using the indicated one or more SL P-TCIs in the first-stage SCI.

[0136] The WTRU may obtain TCI information in the second stage SCI and receive the PSSCH based on the SL S-TCI mode indicator. The WTRU may receive the PSSCH using the indicated SL P-TCI in the first stage SCI and / or further using the indicated SL S-TCI in the second stage SCI.

[0137] At 518, the WTRU may determine whether the SL S-TCI mode indicator has been activated and / or configured. For example, the WTRU may check the first stage SCI at 518 to determine whether the SL S-TCI mode indicator has been configured. If the SL S-TCI mode is configured, the WTRU may check the value of the SL S-TCI mode indicator in the first stage SCI at 520. The value of the SL S-TCI mode indicator may be 1 when the SL S-TCI mode is activated and 0 when the SL S-TCI mode is not activated. At 522, the WTRU may determine whether the S-TCI mode indicator is set to 1. If the value of the SL S-TCI mode indicator is “1” or “on” at 524, the WTRU may check additional TCI control fields and / or acquire the SL S-TCI in the second stage SCI. At 528, the WTRU may receive the PSSCH using both the SL P-TCI and the SL S-TCI indicated in the first and / or second stage SCI. If the value of the SL S-TCI indicator is "0" or "off" at 532, there may be no additional control field for the SL S-TCI, and / or the WTRU may not acquire the SL S-TCI in the second stage SCI. At 536, the WTRU may receive the PSSCH using the SL P-TCI (e.g., only the SL P-TCI) indicated in the first stage SCI.

[0138] At 540, if the SL S-TCI mode is not configured, the SL S-TCI mode indicator may not be present in the first stage SCI. At 544, an additional control field for the SL S-TCI may be absent in the second stage SCI. The WTRU may not acquire the SL S-TCI in the second stage SCI. At 548, the WTRU may receive the PSSCH using only the SL P-TCI indicated in the first stage SCI (e.g., only the SL P-TCI).

[0139] If the SL S-TCI mode indicator is "1", the SL S-TCI control field is present in the second stage SCI. If the SL S-TCI mode indicator is "0", the SL S-TCI control field is not present or absent in the second stage SCI.

[0140] 6 illustrates an example method 600 for TCI adaptation. The fast TCI adaptation procedure may be enabled and / or achieved using the SL S-TCI mode indicator. The criteria for fast TCI adaptation may be based on the channel condition and / or the degree of channel uncertainty.

[0141] At 604, the WTRU may be pre-configured for TCI configuration. At 606, the WTRU may determine channel uncertainty. Depending on the channel uncertainty, the SL S-TCI mode indicator may be set appropriately. At 608, if the channel uncertainty is high, the SL S-TCI mode indicator during the first stage SCI may be set to "enabled." At 612, if the channel uncertainty is low, the SL S-TCI mode indicator during the first stage SCI may be set to "disabled."

[0142] At 616, the WTRU may be TCI indicated (e.g., via the SL MAC CE) to receive the first-stage SCI and / or the second-stage SCI. At 620, the WTRU may receive the first-stage SCI and obtain the SL P-TCI. At 624, the WTRU may receive the second-stage SCI.

[0143] At 626, the WTRU may determine whether the SL S-TCI mode indicator is enabled, for example, in the first stage SCI. If the SL S-TCI mode indicator in the first stage SCI indicates "enabled" at 628, the WTRU may check additional control fields and / or acquire additional TCIs (e.g., SL S-TCIs) in the second stage SCI. At 632, the WTRU may receive the PSSCH using both the SL P-TCI and / or the SL S-TCI. If the SL S-TCI mode indicator in the first stage SCI indicates "disabled" at 636, the additional control field for the SL S-TCI may not be present, and the WTRU may not acquire the SL S-TCIs in the second stage SCI. At 640, the WTRU may receive the PSSCH using the SL P-TCI (e.g., only the SL P-TCI).

[0144] In a slot, 7 to 14 SL symbols may be preconfigured. The PSSCH may be sent in 5 to 12 consecutive SL symbols. The number of PSSCH symbols may depend on the number of SL symbols in the slot and / or whether the PSFCH may be sent in the slot. In 2 or 3 SL symbols carrying the PSCCH, the PSSCH may be multiplexed with the PSCCH. If the PSCCH does not span all L_PSSCH subchannels, the PSSCH may be multiplexed with the PSCCH in the frequency domain. Each PSSCH subchannel may consist of one or more physical resource blocks (PRBs). The L-PSSCH subchannel may have L subchannels, where L may be 1 or greater than 1. This may result in two or three PSCCH / PSSCH symbols. If the PSCCH spans all L_PSSCH subchannels, the PSSCH may be multiplexed with the PSCCH in the time domain. In SL symbols without a PSCCH, the PSSCH spans all L_PSSCH subchannels. In an example, if the PSCCH does not span the entire L_PSSCH subchannel, the PSSCH may be multiplexed with the PSCCH in the frequency domain.

[0145] FIG. 7 illustrates an example scenario 700 for a physical sidelink shared channel (PSSCH) multiplexed with a second SCI in the frequency domain and the second SCI multiplexed with the PSSCH in the time domain. As shown in FIG. 7, second-stage SCIs 704 and 708 may be multiplexed with a PSCCH 712 in the second and third OFDM symbols in the frequency domain. Here, the SCIs may be multiplexed with the PSSCH in the time domain. One beam, TCI, one set of beams, and / or one set of TCIs (e.g., wide beams and / or primary beams) may be used for both the PSCCH and / or the second-stage SCIs. Another beam, TCI, another set of beams, and / or another set of TCIs (e.g., narrow beams and / or primary and / or secondary beams) may be used for the PSSCH. In this configuration, the example method described in FIG. 3 may be applied. In an example, in the same beam, a TCI, a set of beams, and / or a set of TCIs may be used for the PSCCH and / or the second-stage SCI. Additionally or alternatively, the same beam, TCI, a set of beams, and / or a set of TCIs may be used for the PSCCH, the second-stage SCI, and / or the PSSCH.

[0146] 8 is another example scenario 800 for a PSSCH multiplexed with a second SCI in the frequency domain and a second SCI multiplexed with a PSSCH in the time domain. As shown in FIG. 8, a second-stage SCI 804 may be multiplexed with a PSCCH 808 and / or a PSSCH 812 in the second and third OFDM symbols in the frequency / time domain. The second-stage SCI may be multiplexed with a PSSCH 816, 820 in the fifth and sixth OFDM symbols and subsequent OFDM symbols in the time domain. One beam, TCI, one set of beams, and / or one set of TCIs (e.g., a wide beam and / or a primary beam) may be used for the PSCCH, the second-stage SCI multiplexed with the PSCCH in the frequency domain, and / or the PSSCH. A different beam, TCI, different set of beams, and / or different set of TCIs (e.g., narrow beams or primary and / or secondary beams) may be used for another PSSCH multiplexed with the PSCCH in the time domain. The exemplary method described in FIG. 3 may be applied. In an example, the same beam, TCI, set of beams, and / or set of TCIs may be used for the PSCCH and / or second-stage SCI. Additionally or alternatively, the same beam, TCI, set of beams, and / or set of TCIs may be used for the PSCCH, second-stage SCI, and / or PSSCH.

[0147] FIG. 9 illustrates an exemplary scenario 900 for a second SCI multiplexed with a PSSCH in the time domain. Furthermore, FIG. 9 illustrates an example in which the PSCCH spans the entire L_PSSCH subchannel, and the PSSCH may be multiplexed with the PSCCH in the time domain. The second-stage SCI may not be multiplexed with the PSSCH in the frequency domain. Instead, the second-stage SCI may be time-multiplexed with the PSSCH 904, 908 in the fifth and sixth OFDM symbols. The second-stage SCI may be multiplexed with the PSSCH in the time domain. One beam and / or TCI (e.g., a wide beam) may be used for the PSCCH, another beam and / or TCI (e.g., a wide beam and / or primary beam) may be used for the second-stage SCI, and / or another beam and / or TCI (e.g., a narrow beam or primary and / or secondary beam) may be used for the PSSCH. The exemplary method described in FIG. 4 may be applied. The same beam, TCI, set of beams, and / or set of TCIs may be used for the PSCCH and / or second-stage SCI. Additionally or alternatively, the same beam, TCI, set of beams, and / or set of TCIs may be used for the PSCCH, second-stage SCI, and / or PSSCH.

[0148] FIG. 10 illustrates an exemplary scenario 1000 for a second SCI multiplexed with a PSSCH in the frequency domain. As shown in FIG. 10, another example includes that the second-stage SCI 1000 may be multiplexed with a PSSCH in the frequency domain in the fifth OFDM symbol. The second-stage SCI may be multiplexed with a PSSCH in the time domain for another OFDM symbol. One beam and / or TCI (e.g., a wide beam) may be used for the PSCCH, another beam and / or TCI (e.g., a wide beam and / or a primary beam) may be used for the second-stage SCI and / or some PSSCHs, and another beam and / or TCI (e.g., a narrow beam and / or a primary and / or secondary beam) may be used for other PSSCHs other than the frequency multiplexed with the SCI. The exemplary method described in FIG. 4 may be applied.

[0149] The same beam, TCI, set of beams, and / or set of TCIs may be used for the PSCCH and / or second-stage SCI. Additionally or alternatively, the same beam, TCI, set of beams, and / or set of TCIs may be used for the PSCCH, second-stage SCI, and / or PSSCH. Additionally or alternatively, if the PSSCH and second-stage SCI are multiplexed in the frequency domain, the WTRU may receive them using the same beam, TCI, set of beams, and / or set of TCIs. If the PSSCH and second-stage SCI are multiplexed in the frequency domain, the WTRU may receive them simultaneously using different beams, TCIs, sets of beams, and / or sets of TCIs. The WTRU may receive the PSSCH and / or second-stage SCI using different beams, TCIs, sets of beams, and / or sets of TCIs in parallel, depending on the capabilities of the WTRU.

[0150] The beams and / or TCIs used for the PSCCH, second-stage SCI, and PSSCH may be of the same or different types (e.g., primary and / or secondary beams or TCIs), may be the same and / or different beams, and may employ the same or different numbers of beams. This configuration may be based, for example, on channel conditions and / or channel uncertainty, etc. Operation may be adapted to dynamically handle changing channels, channel uncertainty, and / or interference.

[0151] When a TCI and / or set of TCIs is indicated, if the switch timeline is below a predefined or preconfigured threshold, the indicated TCI and / or set of TCIs may be applied. If the timeline is below or above a predefined and / or preconfigured threshold, the indicated TCI and / or set of TCIs may not be applied. A default TCI and / or default set of TCIs may be applied instead. The default TCI and / or default set of TCIs may be configured, preconfigured, and / or predefined.

[0152] In examples, the channel uncertainty (CU) may be based on multiple factors including, but not limited to, the number of LBT failures, the ratio of LBT failures to total measurements, the ratio of LBT failures to successes, the ratio of NACKs to ACKs, the percentage of NACKs, the CBR, the interference level, and / or combinations thereof.

[0153] FIG. 11 shows an example method 1100 of determining channel uncertainty. At 1004, a WTRU may be pre-configured for TCI configuration. At 1108, the WTRU may be pre-configured for CU measurements. At 1110, the WTRU may determine whether the CU measurements are greater than a threshold T. At 1112, if the CU measurements are greater than the threshold T, the channel uncertainty may be determined to be “high.” At 1116, if the CU measurements are equal to or less than T, the channel uncertainty may be determined to be “low.” At 1120, the WTRU may be indicated with a TCI determined based on the channel uncertainty for reception. The CU measurements may include the number of LBT failures, the ratio of LBT failures to total measurements, the ratio of LBT failures to successes, the ratio of NACKs to ACKs, the NACK rate, the CBR, the interference level, etc.

[0154] FIG. 12 shows another example method 1200 of determining channel uncertainty. At 1204, the WTRU may be pre-configured for TCI configuration. At 1208, the WTRU may be pre-configured for CU measurements. At 1210, the WTRU may determine whether a first CU measurement is greater than a first threshold T1. At 1212, if the first CU measurement 1 is greater than the first threshold T1, the CU may be determined to be "high." If the first CU measurement 1 is not greater than the first threshold T1, the second CU measurement 2 may be further checked. At 1214, the WTRU may determine whether the second CU measurement is greater than a second threshold T2. At 1212, if the first CU measurement 1 is greater than the second threshold T2, the CU may be determined to be "high." If the first CU measurement 1 is equal to or less than T2, the CU may be determined to be "low." At 1224, the WTRU may be indicated with a TCI determined based on the channel uncertainty for reception. The first CU measurement 1 and the second CU measurement 2 may include the number of LBT failures, the ratio of LBT failures to total measurements, the ratio of LBT failures to successes, the ratio of NACKs to ACKs, the rate of NACKs, the CBR, the interference level, etc.

[0155] 13 shows an example method 1300 for TCI adaptation. At 1304, the WTRU may be pre-configured for TCI configuration. Depending on the CU, an SL S-TCI mode indicator may be set appropriately. At 1308, the WTRU may be indicated with a TCI to receive the first-stage SCI. At 1312, the WTRU may receive the first-stage SCI and / or acquire the SL P-TCI. At 1316, the WTRU may receive the second-stage SCI using the indicated SL P-TCI.

[0156] At 1318, the WTRU may determine whether the SL S-TCI mode indicator is configured. At 1320, if the TCI mode indicator is configured, the WTRU may further check the CU. For example, the WTRU may determine the CU (e.g., whether the CU is low or high) at 1320. If the CU is high, the SL S-TCI mode indicator in the first stage SCI may be set to “enabled” at 1324. If the CU is low, the SL S-TCI mode indicator in the first stage SCI may be set to “disabled” at 1328. The WTRU may be indicated with a TCI to receive the first stage SCI. The WTRU may receive the first stage SCI and obtain an SL P-TCI. The WTRU may receive the second stage SCI using the indicated SL P-TCI. If the SL S-TCI mode indicator is configured, the WTRU may further check the CU. If the CU is high, the SL S-TCI mode indicator may be set to “enabled.” If the CU is low, the SL S-TCI mode indicator may be set to “disabled.” The WTRU may receive a second stage SCI.

[0157] At 1332, when the WTRU receives the first stage SCI, the WTRU may check the SL S-TCI mode indicator in the control field of the first stage SCI. At 1334, the WTRU may determine whether the SL S-TCI mode indicator is equal to 1. When the SL S-TCI mode indicator is equal to 1, the SL S-TCI mode may be enabled. When the SL S-TCI mode indicator is equal to 0, the SL S-TCI mode may be disabled. At 1336, if the SL S-TCI mode indicator in the first stage SCI indicates "enabled," the WTRU may check additional control fields and / or obtain additional TCIs (e.g., SL S-TCI) in the second stage SCI. At 1340, the WTRU may receive the PSSCH using both the SL P-TCI and SL S-TCI indicated in the first stage SCI and / or second stage SCI.

[0158] If the SL S-TCI mode indicator in the first stage SCI indicates "disabled" at 1344, the additional control field for the SL S-TCI may not be present and / or the WTRU may not acquire the SL S-TCI in the second stage SCI. At 1348, the WTRU may receive the PSSCH using the SL P-TCI (e.g., only the SL P-TCI).

[0159] If the SL S-TCI mode indicator is not configured, the WTRU may not check the CU. At 1352, the SL S-TCI mode indicator may not be present in the first stage SCI. At 1356, an additional control field for the SL S-TCI may not be present, and / or the WTRU may not acquire the SL S-TCI in the second stage SCI. At 1360, the WTRU may receive the PSSCH using only the SL P-TCI indicated in the first stage SCI (e.g., only the SL P-TCI).

[0160] FIG. 14 shows another example method 1400 of TCI adaptation. At 1404, the WTRU may be pre-configured for TCI configuration. Depending on the CU, an SL S-TCI mode indicator may be set appropriately. If the CU is high, the SL S-TCI mode indicator in the first-stage SCI may be set to “enabled.” If the CU is low, the SL S-TCI mode indicator in the first-stage SCI may be set to “disabled.” At 1408, the WTRU may be indicated with a TCI (e.g., via a sidelink medium access control element (SL MAC CE)) to receive the first-stage SCI and / or the second-stage SCI. At 1412, the WTRU may receive the first-stage SCI and / or acquire the SL P-TCI.

[0161] At 1418, the WTRU may determine whether the SL S-TCI mode indicator is configured. If the SL S-TCI mode indicator is configured, at 1420, the WTRU may further check the CU. For example, the WTRU may determine the CU (e.g., whether the CU is low or high) at 1420. The WTRU may be configured to determine whether to disable the SL S-TCI mode indicator based on the CU (e.g., due to second-stage SCI). If the CU is determined to be high, at 1424, the WTRU may enable the SL S-TCI mode indicator (e.g., the SL S-TCI mode indicator may be set to "enabled"). If the CU is determined to be low, at 1428, the WTRU may disable the SL S-TCI mode indicator (e.g., the SL S-TCI mode indicator may be set to "disabled").

[0162] At 1432, the WTRU may receive the second-stage SCI to obtain additional TCI information. At 1434, the WTRU may determine whether an SL S-TCI mode indicator is equal to 1. When the SL S-TCI mode indicator is equal to 1, the SL S-TCI mode may be enabled. When the SL S-TCI mode indicator is equal to 0, the SL S-TCI mode may be disabled. At 1436, if the SL S-TCI mode indicator in the first-stage SCI indicates "enabled," the WTRU may check additional control fields and obtain additional TCI (e.g., SL S-TCI) in the second-stage SCI. At 1440, the WTRU may receive the PSSCH using both the SL P-TCI and / or the SL S-TCI. When the WTRU receives the first-stage SCI, the WTRU may check the SL S-TCI mode indicator in the control field of the first-stage SCI.

[0163] If the SL S-TCI mode indicator in the first stage SCI indicates "disabled" at 1444, the additional control field for the SL S-TCI may not be present and / or the WTRU may not acquire the SL S-TCI in the second stage SCI. At 1448, the WTRU may receive the PSSCH using the SL P-TCI (e.g., only the SL P-TCI).

[0164] If the SL S-TCI mode indicator is not configured, the WTRU may not check the CU. At 1452, the SL S-TCI mode indicator may not be present in the first stage SCI. At 1456, an additional control field for the SL S-TCI may not be present, and / or the WTRU may not acquire the SL S-TCI in the second stage SCI. At 1460, the WTRU may receive the PSSCH using only the SL P-TCI indicated in the first stage SCI (e.g., only the SL P-TCI).

[0165] The WTRU may know one or more SL TCIs for receiving and / or transmitting first-stage SCIs and / or receiving and / or transmitting second-stage SCIs. For example, the SL TCIs for the first-stage SCIs and / or second-stage SCIs may be configured and / or pre-configured for the WTRU.

[0166] In examples, configuration and / or pre-configuration may be combined with activation and / or indication. For example, in a two-stage configuration scheme, in the first stage, the WTRU may initially receive configuration parameters and / or a set of configuration parameters. The WTRU may receive the configuration parameters and / or a set of configuration parameters through pre-configuration and / or semi-static configuration signaling, such as RRC signaling. In the second stage, the WTRU may receive an activation command in the form of an SL MAC CE or SCI that instructs the WTRU on which of the one or more configuration parameters and / or a subset of the configuration parameters received in the first stage to use.

[0167] The TCIs for the first-stage SCI and / or the second-stage SCI may be preconfigured in the WTRU separately. For example, a first SL TCI may be preconfigured in the WTRU for the first-stage SCI, and a second TCI may be preconfigured in the WTRU for the second-stage SCI. The WTRU may use the first TCI to derive a suitable beam for reception of the first-stage SCI. The WTRU may use the second TCI to derive a suitable beam for reception of the second-stage SCI.

[0168] The TCI for the first-stage SCI and / or the second-stage SCI may be jointly pre-configured in the WTRUs. For example, the joint TCI may be configured in the WTRUs. The WTRUs may use the joint TCI to derive a suitable beam for reception of the first-stage SCI. The WTRUs may use the joint TCI to derive a suitable beam for reception of the second-stage SCI.

[0169] An SL TCI for the first-stage SCI, referred to herein as the first TCI, may be pre-configured in the WTRU. The WTRU uses the first TCI for the first-stage SCI to derive a second TCI for the second-stage SCI. In an example, the first TCI and / or the second TCI may be separate TCIs. The WTRU may use the first TCI to derive a suitable beam for reception of the first-stage SCI. The WTRU may use the second TCI to derive a suitable beam for reception of the second-stage SCI. In an example, the first TCI and / or the second TCI may be a joint TCI. The WTRU may use the joint TCI to derive a suitable beam for reception of the first-stage SCI and / or a suitable beam for reception of the second-stage SCI.

[0170] The SL TCI for the first-stage SCI and / or the second-stage SCI may be activated to the WTRU. The TCI for the first-stage SCI and / or the second-stage SCI may be activated separately to the WTRU. For example, a first SL TCI may be activated to the WTRU for the first-stage SCI, and / or a second TCI may be activated to the WTRU for the second-stage SCI. The WTRU may use the first TCI to derive a suitable beam for reception of the first-stage SCI. The WTRU may use the second TCI to derive a suitable beam for reception of the second-stage SCI.

[0171] The TCIs for the first-stage SCI and the second-stage SCI may be jointly activated in the WTRU. For example, a joint TCI may be activated in the WTRU. The WTRU may then use the joint TCI to derive a beam suitable for reception of the first-stage SCI and / or a beam suitable for reception of the second-stage SCI.

[0172] An SL TCI for the first-stage SCI, referred to herein as the first TCI, may be activated in the WTRU. The WTRU may use the first TCI for the first-stage SCI to derive a second TCI for the second-stage SCI. For example, the first TCI and / or the second TCI may be separate TCIs. The WTRU may use the first TCI to derive a suitable beam for reception of the first-stage SCI. The WTRU may use the second TCI to derive a suitable beam for reception of the second-stage SCI. In an example, the first TCI and / or the second TCI may be a joint TCI. The WTRU may use the joint TCI to derive a suitable beam for reception of the first-stage SCI and / or a suitable beam for reception of the second-stage SCI.

[0173] Both two-stage PC5 RRC and SL MAC CE and / or three-stage PC5 RRC, SL MAC CE, and SCI as signaling approaches to configuring and / or activating a TCI for a WTRU also apply to TCIs for first-stage SCIs and / or second-stage SCIs as described above. In two-stage SL TCI indication, PC5 RRC may be used to configure a set of SL TCI states. The SL MAC CE may be used to indicate the exact SL TCI state of the configured set of SL TCI states for the WTRU. In three-stage SL TCI indication, PC5 RRC may be used to configure the SL TCI states. The SL MAC CE may be used to activate a subset of the SL TCI states of the configured set of SL TCI states. The SCI (e.g., first-stage SCI and second-stage SCI) may be used to indicate the exact SL TCI state of the activated subset of SL TCI states for the WTRU.

[0174] The two-stage and / or three-stage SL TCI indications may be used to indicate the SL TCI status for an SL data channel (e.g., PSSCH). The two-stage and / or three-stage SL TCI indications may also be used to indicate the SL TCI status for an SL control channel (e.g., PSCCH). Furthermore, such two-stage and / or three-stage SL TCI indications may be used for same-carrier scheduling and / or cross-carrier scheduling. Furthermore, the two-stage and / or three-stage SL TCI indications may be used for same-slot scheduling and / or cross-slot scheduling.

[0175] Hereinafter, the terms SL TCI state and / or TCI state may be used to refer to a configuration element and / or information element (e.g., one or more of TCI-State or SL TCI-State-r18, SL TCI-State-r19 or SL TCI-State-r20, RS, and / or corresponding quasi-co-location (QCL) type, etc.). One or more TCIs may be determined and / or derived from the TCI state. For example, a TCI in a transmission direction of a first WTRU, hereinafter referred to as WTRU1, towards a second WTRU, hereinafter referred to as WTRU2, or a TCI in a transmission direction of WTRU2 towards WTRU1 may be determined from the TCI state.

[0176] The term SL TCI codepoint may be used herein to refer to an allowed value of the SL TCI field in a DCI and / or an SCI. An SL TCI codepoint may map to one or more SL TCI states (e.g., multiple SL TCI states used for either the TCI for WTRU1 in the WTRU2 transmission direction, the TCI for WTRU2 in the WTRU transmission direction, one SL TCI state used for the TCI for WTRU1 in the WTRU2 transmission direction, and / or one TCI state used for the TCI for WTRU2 in the WTRU1 transmission direction). An SL TCI codepoint may map to one or more SL TCIs (e.g., one TCI for WTRU1 in the WTRU2 transmission direction and one TCI for WTRU2 in the WTRU1 transmission direction). A TCI state may correspond to one or more TCIs.

[0177] Both the TCI for WTRU2 in the WTRU1 transmission direction and the TCI for WTRU1 in the WTRU2 transmission direction may be derived from the same TCI state. For example, WTRU2 may use the same SL RS to determine the WTRU2 Rx beam, the WTRU1 Tx beam for WTRU1 in the WTRU2 transmission direction, and / or the WTRU2 Tx beam for WTRU2 in the WTRU1 transmission direction. In this case, a joint pool (e.g., set) of TCI states may be configured for both WTRU1 in the WTRU2 transmission direction and WTRU2 in the WTRU1 transmission direction.

[0178] Separate pools (e.g., sets) of TCI states may be configured (e.g., one pool of TCI states for the transmit direction of WTRU1 to WTRU2 and another pool of TCI states for the transmit direction of WTRU2 to WTRU1). For example, a first SL RS may be used to determine a WTRU2 Rx beam or a WTRU1 Tx beam for WTRU1 in the WTRU2 transmit direction, and a second SL RS may be used to determine a WTRU2 Tx beam for WTRU2 in the WTRU1 transmit direction.

[0179] The TCI may be configured for the Rx WTRU and / or Tx WTRU at multiple levels of granularity (e.g., per component carrier (CC), per bandwidth portion (BWP), per control resource set (CORESET), per reference signal (RS) type, per Rx WTRU (e.g., from the perspective of the Tx WTRU), per Tx WTRU (e.g., from the perspective of the Rx WTRU), per paired Tx and / or Rx WTRU, per sidelink link ID, per service or destination L2 ID, per source L2 ID and destination L2 ID pair, per source L2 ID, per RS ​​type, per channel (e.g., PSBCH, PSCCH, PSSCH, PSFCH), and / or per resource pool).

[0180] The source or target RS type may include SLSS (e.g., S-SSB), SL CSI-RS, SL PT-RS, DMRS for PSCCH, and / or DMRS for PSSCH. The source and / or target channel may include PSBCH, PSCCH, PSSCH, and / or PSFCH.

[0181] Multiple QCL types may be considered for the sidelink, including, for example, QCL-Type A (e.g., Doppler shift, Doppler spread, mean delay, delay spread), QCL-Type B (e.g., Doppler shift, Doppler spread), QCL-Type C (e.g., Doppler shift, mean delay), and / or QCL-Type D (e.g., spatial Rx parameters).

[0182] One or more of the multiple nodes may transmit the source RS. Such nodes include a Tx WTRU (a helper and / or assisting node for the Tx WTRU). The Tx WTRU may transmit the source RS to the Rx WTRU with or without assistance from the Rx WTRU (e.g., a helper or assisting node for the Tx WTRU). Such nodes may further include an Rx WTRU (a helper and / or assisting node for the Rx WTRU). The Rx WTRU may transmit the source RS to the Tx WTRU (e.g., supporting HARQ feedback via the PSFCH) with or without assistance from the Tx WTRU (e.g., a helper or assisting node for the Rx WTRU).

[0183] One or more of the multiple nodes may configure, activate, and / or both configure and / or activate the TCI configuration. Such nodes may include the Tx WTRU's serving cell and / or a control node. The WTRU may configure the Tx WTRU with or without assistance from the Rx WTRU and / or its serving cell. The Tx WTRU's serving cell and / or a control node may activate pre-configured TCI information for the Tx WTRU with or without assistance from the Rx WTRU and / or its serving cell.

[0184] Additional nodes that may transmit the source RS include the Rx WTRU's serving cell and / or control node, which may configure the Rx WTRU with or without assistance from the Tx WTRU and / or the Tx WTRU's serving cell with TCI information. The Tx WTRU's serving cell or control node may activate pre-configured TCI information for the Rx WTRU with or without assistance from the Tx WTRU and / or the Tx WTRU's serving cell.

[0185] The Tx WTRU (e.g., a helper or assisting node for the Tx WTRU) may configure TCI information for the Rx WTRU with or without assistance information from the Rx WTRU and / or the Rx WTRU's serving cell. The Tx WTRU (e.g., a helper or assisting node for the Tx WTRU) may activate pre-configured TCI information for the Rx WTRU with or without assistance information from the Rx WTRU and / or the Rx WTRU's serving cell.

[0186] The Rx WTRU (e.g., a helper or assisting node for the Rx WTRU) may configure TCI information for the Tx WTRU with or without assistance information from the Rx WTRU and / or the Rx WTRU's serving cell. The Rx WTRU (e.g., a helper or assisting node for the Rx WTRU) may activate pre-configured TCI information for the Tx WTRU with or without assistance information from the Rx WTRU and / or the Rx WTRU's serving cell.

[0187] In an example, the WTRU may perform beam and TCI adaptation (e.g., in a shared spectrum to increase reception opportunities, improve performance, and / or reduce signaling overhead). The WTRU may be pre-configured for a TCI configuration. Depending on the CU, the SL S-TCI mode indicator may be set appropriately. If the CU is high, the SL S-TCI mode indicator during the first stage SCI may be set to "enabled." If the CU is low, the SL S-TCI mode indicator during the first stage SCI may be set to "disabled."

[0188] The WTRU may be TCI indicated (e.g., via the SL MAC CE) to receive the first stage SCI and / or the second stage SCI. The WTRU may receive the first stage SCI and / or obtain the SL P-TCI. If the SL S-TCI mode indicator is configured, the WTRU may further check the CU. If the CU is high, the SL S-TCI mode indicator is set to "enabled." If the CU is low, the SL S-TCI mode indicator may be set to "disabled."

[0189] When the WTRU receives the first stage SCI, it may check the SL S-TCI mode indicator in the control field of the first stage SCI. The WTRU may receive the second stage SCI to obtain additional TCI information. If the SL S-TCI mode indicator in the first stage SCI indicates "valid," the SL S-TCI mode indicator may check additional control fields and obtain additional TCI (e.g., SL S-TCI in the second stage SCI). The WTRU may receive the PSSCH using both the SL P-TCI and / or the SL S-TCI to increase reception opportunities and / or improve performance.

[0190] If the SL S-TCI mode indicator in the first stage SCI indicates "disabled," there may be no additional control field for the SL S-TCI. The WTRU may not acquire the SL S-TCI in the second stage SCI. The WTRU may receive the PSSCH using the SL P-TCI (e.g., only the SL P-TCI) to reduce signaling overhead.

[0191] If the SL S-TCI mode indicator is not configured, the WTRU may not check the CU. An additional control field for the SL S-TCI may not be present. The WTRU may not acquire the SL S-TCI in the second stage SCI. The WTRU may receive the PSSCH using the SL P-TCI (e.g., only the SL P-TCI).

[0192] In an example, the WTRU performs beam and / or TCI adaptation (e.g., in a shared spectrum to increase reception opportunities, improve performance, and / or reduce signaling overhead). The WTRU may be pre-configured for a TCI configuration. Depending on the CU, an SL S-TCI mode indicator may be set appropriately. If the CU is high, the SL S-TCI mode indicator in the first-stage SCI may be set to “enabled.” If the CU is low, the SL S-TCI mode indicator in the first-stage SCI may be set to “disabled.” The WTRU may be indicated with a TCI to receive the first-stage SCI. The WTRU may receive the first-stage SCI and obtain an SL P-TCI. The WTRU may receive the second-stage SCI using the indicated SL P-TCI. If the SL S-TCI mode indicator is configured, the WTRU may further check the CU. If the CU is high, the SL S-TCI mode indicator is set to “enabled.” If the CU is low, the SL S-TCI mode indicator is set to “disabled.” The WTRU may receive the second stage SCI.

[0193] When the WTRU receives the first stage SCI, the WTRU may check the SL S-TCI mode indicator in the control field of the first stage SCI. If the SL S-TCI mode indicator in the first stage SCI indicates "enabled," the WTRU may check additional control fields and obtain additional TCIs (e.g., SL S-TCI in the second stage SCI). The WTRU may receive the PSSCH using both the SL P-TCI and the SL S-TCI. If the SL S-TCI mode indicator in the first stage SCI indicates "disabled," the additional control field for the SL S-TCI may not be present. The WTRU may not obtain the SL S-TCI in the second stage SCI. The WTRU may receive the PSSCH using the SL P-TCI (e.g., only the SL P-TCI). If the SL S-TCI mode indicator is not configured, the WTRU may not check the CU. The additional control field for the SL S-TCI may not be present. The WTRU may not acquire the SL S-TCI during the second stage SCI. The WTRU may receive the PSSCH using the SL P-TCI (eg, only the SL P-TCI).

[0194] The CU may be determined based on any combination of factors, including the number of LBT failures, the ratio of LBT failures to total measurements, the ratio of LBT failures to successes, the ratio of NACKs to ACKs, the percentage of NACKs, the channel busy rate (CBR), the interference level, etc.

[0195] The methods and solutions described herein may be applied to reception of a sidelink data channel, a sidelink control channel, a sidelink reference signal, other signals or channels, etc. The methods and solutions described herein may be applied to transmission of a sidelink data channel, a sidelink control channel, a sidelink feedback channel, a sidelink reference signal, other signals or channels, etc. The methods and solutions described herein may be applied to different cast types, such as unicast, groupcast, and multicast. The methods and solutions described herein may be applied to unlicensed spectrum, shared spectrum, licensed spectrum, etc. The methods and solutions described herein may be applied to single-stage, two-stage, and / or multi-stage communications, e.g., reception and / or transmission of a two-stage sidelink control channel (e.g., a first-stage SCI and / or a second-stage SCI).

Claims

1. 1. A wireless transmit / receive unit (WTRU), comprising: receiving configuration information comprising a sidelink (SL) secondary transmission configuration indicator (S-TCI) mode indicator; receiving first stage SL control information (SCI) indicating one or more SL primary transmission configuration indicators (P-TCI); determining whether to enable or disable the SL S-TCI mode indicator for second stage SCI based on channel uncertainty; receiving the second stage SCI; determining one or more SL S-TCIs using the second stage SCI in response to the SL S-TCI indicator remaining enabled for the second stage SCI; receiving a physical sidelink shared channel (PSSCH) transmission using the one or more SL P-TCIs and the one or more SL S-TCIs based on the SL S-TCI mode indicator being enabled for the second stage SCI; WTRU, comprising a processor and memory configured to:

2. The WTRU of claim 1 , wherein the processor and memory are further configured to determine the channel uncertainty based on one or more channel uncertainty measurements.

3. The WTRU of claim 2 , wherein the processor and memory are further configured to determine that the channel uncertainty is high based on the one or more channel uncertainty measurements being greater than a predetermined threshold.

4. The WTRU of claim 3 , wherein the processor and memory are further configured to enable the SL S-TCI mode indicator based on the channel uncertainty being determined to be high.

5. The WTRU of claim 3 , wherein the processor and memory are configured to disable the SL S-TCI mode indicator based on the channel uncertainty being determined to be low.

6. 6. The WTRU of claim 2, wherein the one or more channel uncertainty measurements include one or more of: a number of listen-before-talk (LBT) failures, a ratio of LBT failures to total measurements, a ratio of LBT failures to successes, a ratio of negative acknowledgements (NACKs) to positive acknowledgements (ACKs), a NACK percentage, a channel busy ratio (CBR), or an interference level.

7. The WTRU of claim 1 , wherein the one or more SL S-TCIs are determined based on a control field in the second stage SCI.

8. The WTRU of claim 1 , wherein the second stage SCI is received using the SLP P-TCI.

9. 9. The WTRU of claim 1, wherein the processor and memory are further configured to receive an SL MAC CE indicating an SL TCI to be used to receive the first stage SCI and the second stage SCI.

10. 1. A method implemented by a wireless transmit / receive unit (WTRU), comprising: receiving configuration information comprising a sidelink (SL) secondary transmission configuration indicator (S-TCI) mode indicator; receiving first stage SL control information (SCI) indicating one or more SL primary transmission configuration indicators (P-TCI); determining whether to enable or disable the SL S-TCI mode indicator for second stage SCI based on channel uncertainty; receiving the second stage SCI; determining one or more SL S-TCIs using the second stage SCI in response to the SL S-TCI indicator remaining enabled for the second stage SCI; and receiving a physical sidelink shared channel (PSSCH) transmission using the one or more SL P-TCIs and the one or more SL S-TCIs based on the SL S-TCI mode indicator being enabled for the second stage SCI; A method comprising:

11. The method of claim 10 , wherein the WTRU is further configured to determine the channel uncertainty based on one or more channel uncertainty measurements.

12. The method of claim 11 , wherein the WTRU is further configured to determine that the channel uncertainty is high based on the one or more channel uncertainty measurements being greater than a predetermined threshold.

13. The method of claim 12 , wherein the WTRU is further configured to enable the SL S-TCI mode indicator based on the channel uncertainty being determined to be high.

14. The method of claim 12 , wherein the WTRU is configured to disable the SL S-TCI mode indicator based on the channel uncertainty being determined to be low.

15. 15. A method according to any one of claims 11 to 14, wherein the one or more channel uncertainty measurements include one or more of: a number of listen-before-talk (LBT) failures, a ratio of LBT failures to total measurements, a ratio of LBT failures to successes, a ratio of negative acknowledgements (NACKs) to positive acknowledgements (ACKs), a NACK percentage, a channel busy ratio (CBR), or an interference level.

16. The method according to any of claims 10 to 15, wherein the one or more SL S-TCIs are determined based on a control field in the second stage SCI.

17. The method according to any of claims 10 to 16, wherein the second stage SCI is received using the SL P-TCI.

18. 18. The method of claim 10, wherein the processor and memory are further configured to receive an SL MAC CE indicating an SL TCI to be used to receive the first stage SCI and the second stage SCI.

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