Sidelink collision detection and indication

Abstract

This document describes systems, methods, and instruments for sidelink (SL) collision detection and indication (e.g., in new radio (NR) vehicular communications (V2X)). A wireless transmit / receive unit (WTRU) may transmit resource reservations (e.g., in sidelink control information (SCI)). A receiving (RX) WTRU may receive SCIs from (e.g., multiple) transmitting (TX) WTRUs, where the TX WTRUs reserve resources for transmission. TX WTRUs may be unaware of other TX WTRUs (e.g., they may not know the resources reserved by other TX WTRUs). For example, if reserved resources overlap (e.g., partially or completely), the resources may be conflicting. For instance, a collision may occur if multiple TX WTRUs reserve conflicting resources for transmission and / or if a TX WTRU reselects a non-conflicting resource for transmission.

Description

Technical Field

[0001] Cross-referencing of related applications

[0002] This application claims priority to U.S. Provisional Application No. 63 / 228,653, filed August 3, 2021, and U.S. Provisional Application No. 63 / 249,260, filed September 28, 2021, the contents of which are incorporated herein by reference in their entirety.

[0003] This invention relates to a system, method, and instrument for sidelink (SL) collision detection and indication (e.g., in new radio (NR) vehicular communications (V2X)). Prior Technology

[0004] Mobile communications, which utilize wireless communication, continue to evolve. Fifth-generation mobile communication radio access technology (RAT) can be referred to as 5G new radio (NR). The previous generation of mobile communications RAT could be, for example, fourth-generation (4G) long-term evolution (LTE) technology. Summary of the Invention

[0005] This document describes systems, methods, and instruments for sidelink (SL) collision detection and indication (e.g., in new radio (NR) vehicular communications (V2X)). A wireless transmit / receive unit (WTRU) may transmit resource reservations (e.g., in sidelink control information (SCI)). A receiving (RX) WTRU may receive SCIs from (e.g., multiple) transmitting (TX) WTRUs, where the TX WTRUs reserve resources for transmission. TX WTRUs may be unaware of other TX WTRUs (e.g., they may not know the resources reserved by other TX WTRUs). For example, if reserved resources overlap (e.g., partially or completely), the resources may be conflicting. For instance, a collision may occur if multiple TX WTRUs reserve conflicting resources for transmission and / or if a TX WTRU reselects a non-conflicting resource for transmission.

[0006] The RX WTRU (e.g., the first WTRU) may receive configuration information indicating the conflict detection processing time (e.g., the time used by the RX WTRU to determine the existence of a conflict and send a conflict indication). The RX WTRU may receive a first SCI from the first TX WTRU (e.g., the second WTRU). The first SCI may include an indication (e.g., a first indication) indicating a first resource, a first conflict indication setting, and a first priority value. The RX WTRU may receive an indication indicating, for example, the conflict indication processing time associated with the first TX WTRU. The RX WTRU may determine the conflict detection triggering timing (e.g., a time window in which the RX WTRU has sufficient time to detect a conflict and send a conflict indication (e.g., to the first TX WTRU), for example, based at least on the conflict detection processing time and the first resource. The conflict detection triggering timing may be determined, for example, based on the conflict detection processing time, the conflict indication processing time (e.g., associated with the first TX WTRU), and the first resource. The RX WTRU may receive a second SCI from a second TX WTRU (e.g., a third WTRU) during a collision detection triggering event, for example. The second SCI may include indications of a second resource, a second collision indication setting, and / or a second priority value (e.g., a second indication). The RX WTRU may determine that a collision exists associated with the first and second resources. For example, the RX WTRU may determine that a collision exists associated with the first and second resources based on a determination that a measurement associated with the second SCI (e.g., reference signal received power (RSRP)) is greater than a first threshold. For example, the RX WTRU may determine that a collision exists associated with the first and second resources based on a determination that the first and second resources overlap (e.g., partially or completely). The RX WTRU may send a collision indication, for example, to the first TX WTRU. The RX WTRU may send a collision indication to the first TX WTRU, for example, based on a determination that a first collision indication setting is enabled and a second collision indication setting is disabled. The RX WTRU may send a conflict indication to the first TX WTRU, for example, based on the determination that a first conflict indication setting is enabled, a second conflict indication setting is enabled, and a first priority value is greater than a second priority value. Simple Explanation of the Diagram

[0007] [Figure 1A] is a system diagram illustrating one or more instance communication systems that can be implemented in the disclosed embodiments. [Figure 1B] is a system diagram illustrating an example wireless transmit / receive unit (WTRU) that can be used in the communication system illustrated in Figure 1A according to an embodiment. [Figure 1C] is a system diagram illustrating an example radio access network (RAN) and an example core network (CN) that can be used in the communication system illustrated in Figure 1A according to an embodiment. [Figure 1D] is a system diagram illustrating a further example RAN and a further example CN that can be used in the communication system illustrated in Figure 1A according to an embodiment. Figures 2A to 2D illustrate examples of WTRU collision detection triggering timing for retransmission of resource reservation. [Figure 3] illustrates an example of an RX WTRU performing conflict detection and conflict indication. Figures 4A to 4C illustrate examples of PSICH transmission. [Figure 5A] illustrates an example of a PSICH transfer used for one-time resource reselection. [Figure 5B] illustrates an example of PSICH transmission used for periodic resource selection. Implementation

[0008] This document describes systems, methods, and instruments for side-link (SL) collision detection and indication (e.g., in New Radio (NR) Vehicle-to-Everything (V2X) communication). A receiver (RX) radio transmit / receive unit (WTRU) can, for example, determine the triggering of collision detection for one or more resources reserved in a received SL control information (SCI) associated with (pre)configured WTRU information and / or a destination identifier (ID), based on information indicated in received SCIs (e.g., L1 priority and time resources) and / or (pre)configuration parameters (e.g., channel busy ratio (CBR) and L1 priority thresholds). The RX WTRU can, for example, detect collisions and / or collision types based on SCI decoding in a set of SL time slots, where SCI decoding can be based, for example, on reserved time resources, reference signal received power (RSRP) threshold configuration, and / or indicated resource reservation periods. An RX WTRU can determine if a TX WTRU is transmitting a Physical Side Link Indicator Channel (PSICH) transmission, and whether it is using the corresponding PSICH format and resource indication for one-time resource reselection, periodic resource reselection, or cancellation of retransmission, for example, due to detected collisions. The TX WTRU behavior can be determined, for example, based on receiving PSICH transmissions according to PSICH information (e.g., including disabling resource preemption).

[0009] Figure 1A illustrates one or more example communication systems 100 that can be implemented according to the disclosed embodiments. Communication system 100 may be a multi-access system that provides content (such as voice, data, video, communications, broadcasts, etc.) to multiple wireless users. Communication system 100 enables 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-tail unique-word DFT-Spread OFDM (ZT UW DTS-s OFDM), unique word OFDM (UW-OFDM), resource block filtered OFDM, filter bank multicarrier (FBMC), and similar methods.

[0010] As shown in Figure 1A, the communication system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, RAN 104 / 113, CN 106 / 115, public switched telephone network (PSTN) 108, Internet 110, and other networks 112, although it will be understood that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network elements. Each of the WTRUs 102a, 102b, 102c, and 102d may be configured to operate and / or communicate in a wireless environment of any type. For example, WTRU 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 radio, fixed or mobile subscriber unit, subscription-based unit, pager, cellular phone, personal digital assistant (PDA), smartphone, laptop, laptop, personal computer, wireless sensor, hotspot or Mi-Fi device, Internet of Things (IoT) device, watch or other wearable, head-mounted display (HMD), vehicle, drone, medical device and application (e.g., remote surgery), industrial device and application (e.g., robot and / or other wireless device operating in the context of industrial and / or automated processing chains), consumer electronics, device operating on commercial and / or industrial wireless networks, and the like. Any of WTRU 102a, 102b, 102c, and 102d may be referred to as UE interchangeably.

[0011] The communication system 100 may also include base stations 114a and / or 114b. Each of base stations 114a and 114b may be any type of device configured to wirelessly interface with at least one of WTRUs 102a, 102b, 102c, and 102d to facilitate access to one or more communication networks (such as CN 106 / 115, Internet 110, and / or other networks 112). For example, base stations 114a and 114b may be base transceiver stations (BTS), node B, eNode B, home node B, home eNode B, gNB, NR node B, station controller, access point (AP), wireless router, and the like. Although base stations 114a and 114b are each depicted as a single element, it will be understood that base stations 114a and 114b may include any number of interconnected base stations and / or network elements.

[0012] Base station 114a may be part of RAN 104 / 113, which may also include other base stations and / or network components (not shown), such as base station controllers (BSCs), radio network controllers (RNCs), relay nodes, etc. Base station 114a and / or base station 114b may be configured to transmit and / or receive radio signals on one or more carrier frequencies, which may be referred to as cells (not shown). These frequencies may be in licensed spectrum, unlicensed spectrum, or a combination of licensed and unlicensed spectrum. A cell may provide coverage for a specific geographical area that may be relatively fixed or change over time. The cell may be further divided into cell sectors. For example, the cell associated with base station 114a may be divided into three sectors. Therefore, in one embodiment, base station 114a may include three transceivers, i.e., one transceiver for each sector of the cell. In one embodiment, base station 114a may employ multiple-input multiple-output (MIMO) technology, and multiple transceivers may be used for each sector of the cell. For example, beamforming may be used to transmit and / or receive signals in a desired spatial direction.

[0013] Base stations 114a and 114b can communicate with one or more of WTRUs 102a, 102b, 102c, and 102d via an air interface 116. This air interface can be any suitable wireless communication link (e.g., radio frequency (RF), microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet (UV), visible light, etc.). The air interface 116 can be established using any suitable radio access technology (RAT).

[0014] More specifically, as mentioned above, communication system 100 may be a multi-access system and may employ one or more access schemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and similar schemes. For example, base stations 114a and WTRUs 102a, 102b, and 102c in RAN 104 / 113 may implement radio technologies, such as using wideband CDMA (WCDMA) to establish Universal Mobile Telecommunications System (UMTS) terrestrial radio access (UTRA) on air interfaces 115 / 116 / 117. WCDMA may include communication protocols such as High-Speed ​​Packet Access (HSPA) and / or evolved HSPA (HSPA+). HSPA may include High-Speed ​​Downlink Packet Access (HSDPA) and / or High-Speed ​​Uplink Packet Access (HSUPA).

[0015] In one embodiment, base stations 114a and WTRUs 102a, 102b, 102c may implement radio technologies, such as Long Term Evolution (LTE) and / or LTE-Advanced (LTE-A) and / or LTE-Advanced Pro (LTE-A Pro), to establish Evolved UMTS Terrestrial Radio Access (E-UTRA) on the air interface 116.

[0016] In one embodiment, base station 114a and WTRUs 102a, 102b, 102c may implement radio technology, such as using New Radio (NR) to establish NR radio access to the air interface 116.

[0017] In one embodiment, base station 114a and WTRUs 102a, 102b, and 102c may implement multiple radio access technologies. For example, base station 114a and WTRUs 102a, 102b, and 102c may implement LTE radio access and NR radio access together, for example, using the dual connectivity (DC) principle. Therefore, the air interface utilized by WTRUs 102a, 102b, and 102c can be characterized by various types of radio access technologies and / or transmissions to / from various types of base stations (e.g., eNBs and gNBs).

[0018] In other embodiments, base stations 114a and WTRUs 102a, 102b, and 102c may implement radio technologies such as IEEE 802.11 (i.e., Wireless Fidelity, WiFi), IEEE 802.16 (i.e., Global Interoperability Microwave Access (WiMAX)), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Provisional Standard 2000 (IS-2000), Provisional Standard 95 (IS-95), Provisional Standard 856 (IS-856), Global System for Mobile Communications (GSM), GSM Evolution Enhanced Data Rate (EDGE), GSM EDGE (GERAN), and the like.

[0019] Base station 114b in Figure 1A can be a wireless router, home node B, home eNode-B, or access point, and can utilize any suitable RAT to facilitate wireless connectivity in localized areas such as business premises, homes, vehicles, campuses, industrial facilities, air corridors (e.g., for use by drones), roads, and the like. In one embodiment, base station 114b and WTRUs 102c, 102d can implement radio technologies such as IEEE 802.11 to establish a wireless local area network (WLAN). In one embodiment, base station 114b and WTRUs 102c, 102d can implement radio technologies such as IEEE 802.15 to establish a wireless personal area network (WPAN). In yet another embodiment, base station 114b and WTRUs 102c, 102d can utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.) to establish a picocell or femtocell. As shown in FIG1A, base station 114b may have a direct connection to Internet 110. Therefore, base station 114b may not need to access Internet 110 via CN 106 / 115.

[0020] RAN 104 / 113 can communicate with CN 106 / 115 and can be configured to provide voice, data, application, and / or Voice over Internet Protocol (VoIP) services to one or more of WTRU 102a, 102b, 102c, and 102d networks of any type. Data can have different quality of service (QoS) requirements, such as different throughput requirements, latency requirements, fault tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, and the like. CN 106 / 115 can provide call control, billing services, location-based services, prepaid telephone, internet connectivity, video distribution, and / or perform advanced security functions such as user authentication. Although not shown in Figure 1A, it will be understood that RAN 104 / 113 and / or CN 106 / 115 can communicate directly or indirectly with other RANs using the same RAT as RAN 104 / 113 or using different RATs. For example, in addition to connecting to RAN 104 / 113 (which can utilize NR radio technology), CN 106 / 115 can also communicate with another RAN (not shown) that uses GSM, UMTS, CDMA 2000, WiMAX, E-UTRA, or WiFi radio technology.

[0021] CN 106 / 115 may also function as a gateway for WTRU 102a, 102b, 102c, and 102d to access PSTN 108, Internet 110, and / or other networks 112. PSTN 108 may include a circuit-switched telephone network providing plain old telephone service (POTS). Internet 110 may include a global system of interconnected computer networks and devices using common communication protocols, such as Transmission Control Protocol (TCP), User Datagram Protocol (UDP), and / or Internet Protocol (IP) from the TCP / IP protocol suite. Network 112 may include wired and / or wireless communication networks owned and / or operated by other service providers. For example, network 112 may include another CN connected to one or more RANs, which may use the same RAT as RAN 104 / 113 or a different RAT.

[0022] Some or all of the WTRUs 102a, 102b, 102c, and 102d in the communication system 100 may include multi-mode capabilities (e.g., WTRUs 102a, 102b, 102c, and 102d may include multiple transceivers for communicating with different wireless networks via different wireless links). For example, the WTRU 102c shown in Figure 1A may be configured to communicate with base station 114a, which may employ cellular-based radio technology, and with base station 114b, which may employ IEEE 802 radio technology.

[0023] Figure 1B is a system diagram illustrating example WTRU 102. As shown in Figure 1B, WTRU 102 may include, in particular, 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 supply 134, a global positioning system (GPS) chipset 136, and / or other peripheral devices 138, etc. It will be understood that WTRU 102 may include any combination of the above-mentioned elements while remaining consistent with one embodiment.

[0024] Processor 118 may be a general-purpose processor, a special-purpose processor, a conventional processor, a digital signal processor (DSP), a plurality of 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, any other type of integrated circuit (IC), a state machine, and the like. Processor 118 may perform signal encoding / decoding, data processing, power control, input / output processing, and / or any other functionality that enables WTRU 102 to operate in a wireless environment. Processor 118 may be coupled to transceiver 120, which may be coupled to transmitting / receiving element 122. Although Figure 1B depicts processor 118 and transceiver 120 as separate components, it will be understood that processor 118 and transceiver 120 may be integrated together in an electronic package or on a chip.

[0025] Transmit / receive element 122 can be configured to transmit signals to or receive signals from a base station (e.g., base station 114a) via space interface 116. For example, in one embodiment, transmit / receive element 122 can be configured as an antenna to transmit and / or receive RF signals. In one embodiment, for example, transmit / receive element 122 can be configured as a transmitter / detector to transmit and / or receive IR, UV, or visible light signals. In yet another embodiment, transmit / receive element 122 can be configured to transmit and / or receive both RF and optical signals. It should be understood that transmit / receive element 122 can be configured to transmit and / or receive any combination of wireless signals.

[0026] Although the transmit / receive element 122 is depicted as a single element in FIG1B, the WTRU 102 may include any number of transmit / receive elements 122. More specifically, the WTRU 102 may employ MIMO technology. Thus, in one embodiment, the WTRU 102 may include two or more transmit / receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals through the air interface 116.

[0027] Transceiver 120 can be configured to modulate signals to be transmitted via transmit / receive element 122 and demodulate signals received via transmit / receive element 122. As mentioned above, WTRU 102 may have multi-mode capability. Therefore, for example, transceiver 120 may include multiple transceivers for enabling WTRU 102 to communicate via multiple RATs (such as NR and IEEE 802.11).

[0028] The processor 118 of WTRU 102 can be coupled to a speaker / microphone 124, a keypad 126, and / or a display / touchpad 128 (e.g., a liquid crystal display (LCD) unit or an organic light-emitting diode (OLED) display unit) and can receive user input data from them. The processor 118 can also output user data to the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128. Additionally, the processor 118 can access information from any type of suitable memory (such as non-removable memory 130 and / or removable memory 132) and store data in any type of suitable memory. 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. Removable memory 132 may include a subscriber identity module (SIM) card, a memory stick, a secure digital (SD) memory card, and the like. In other embodiments, processor 118 may access information from memory not physically located on WTRU 102 (such as on a server or home computer (not shown)) and store data in that memory.

[0029] The processor 118 may receive power from the power supply 134 and may be configured to distribute and / or control power to other components in the WTRU 102. The power supply 134 may be any suitable device for powering the WTRU 102. For example, the power supply 134 may include one or more dry cell battery packs (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel-metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, and the like.

[0030] 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 alternatively) information from the GPS chipset 136, the WTRU 102 may receive location information from base stations (e.g., base stations 114a, 114b) via the air interface 116, and / or determine its location based on the timing of signals received from two or more nearby base stations. It will be understood that the WTRU 102 may obtain location information using any suitable location determination method while remaining consistent with one embodiment.

[0031] The processor 118 may be further coupled to other peripheral devices 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, peripheral devices 138 may include accelerometers, electronic compasses, satellite transceivers, digital cameras (for photos and / or video), universal serial bus (USB) ports, vibration devices, television transceivers, hands-free headsets, Bluetooth® modules, frequency modulated (FM) radio units, digital music players, media players, video game console modules, internet browsers, virtual reality and / or augmented reality (VR / AR) devices, activity trackers, and the like. Peripheral device 138 may include one or more sensors, such as gyroscopes, accelerometers, Hall effect sensors, magnetometers, orientation sensors, proximity sensors, temperature sensors, time sensors; geolocation sensors; altimeters, light sensors, touch sensors, magnetometers, barometers, gesture sensors, biometric sensors, and / or humidity sensors.

[0032] WTRU 102 may include some or all of the signals (e.g., associated with a specific subframe for both UL (e.g., for transmission) and downlink (e.g., for reception)) for which transmission and reception may be parallel and / or simultaneous full-duplex radio. The full-duplex radio may include an interference management unit to reduce and / or substantially eliminate self-interference via either hardware (e.g., a choke) or via signal processing (e.g., a separate processor (not shown) or via processor 118). In one embodiment, WTRU 102 may include some or all of the signals (e.g., associated with a specific subframe for either UL (e.g., for transmission) or downlink (e.g., for reception) for which transmission and reception may be half-duplex radio.

[0033] Figure 1C is a system diagram illustrating RAN 104 and CN 106 according to one embodiment. As mentioned above, RAN 104 can use E-UTRA radio technology to communicate with WTRUs 102a, 102b, and 102c via air interface 116. RAN 104 can also communicate with CN 106.

[0034] RAN 104 may include eNode-Bs 160a, 160b, and 160c, although it should be understood that RAN 104 may include any number of eNode-Bs while remaining consistent with one embodiment. Each of eNode-Bs 160a, 160b, and 160c may include one or more transceivers for communicating with WTRUs 102a, 102b, and 102c via air interface 116. In one embodiment, eNode-Bs 160a, 160b, and 160c may implement MIMO technology. Therefore, eNode-B 160a, for example, may use multiple antennas to transmit radio signals to and / or receive radio signals from the WTRU 102a.

[0035] Each of the eNode-B 160a, 160b, and 160c can be associated with a specific cell (not shown) and can be configured to handle radio resource management decisions, handover decisions, user scheduling in UL and / or DL, and the like. As shown in Figure 1C, the eNode-B 160a, 160b, and 160c can communicate with each other via the X2 interface.

[0036] The CN 106 shown in Figure 1C may include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (or PGW) 166. Although each of the above elements is depicted as part of the CN 106, it will be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0037] The MME 162 can connect to each of the eNode-Bs 162a, 162b, and 162c in RAN 104 via the S1 interface and can function as a control node. For example, the MME 162 can be responsible for authenticating users of WTRUs 102a, 102b, and 102c, enabling / disabling bearers, and selecting specific service gateways during the initial attachment of WTRUs 102a, 102b, 102c, and similar devices. The MME 162 can provide control plane functions for handover between RAN 104 and other RANs (not shown) employing other radio technologies such as GSM and / or WCDMA.

[0038] The SGW 164 can connect to each of the eNode Bs 160a, 160b, and 160c in RAN 104 via the S1 interface. The SGW 164 can generally route and forward user data packets to / from WTRUs 102a, 102b, and 102c. The SGW 164 can also perform other functions, such as anchoring the user plane during inter-eNode B handover, triggering calls when DL data is available to WTRUs 102a, 102b, and 102c, managing and storing background information for WTRUs 102a, 102b, and 102c, and similar functions.

[0039] SGW 164 can be connected to PGW 166, which provides access to packet switching networks (such as Internet 110) to WTRU 102a, 102b, 102c to facilitate communication between WTRU 102a, 102b, 102c and IP-enabled devices.

[0040] CN 106 can facilitate communication with other networks. For example, CN 106 can provide access to circuit-switched networks (such as PSTN 108) to WTRUs 102a, 102b, and 102c to facilitate communication between WTRUs 102a, 102b, and 102c and conventional terrestrial line communication devices. For example, CN 106 may include an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) or be able to communicate with such IP gateway, which acts as an interface between CN 106 and PSTN 108. Additionally, CN 106 can provide access to other networks 112 to WTRUs 102a, 102b, and 102c, which may include other wired and / or wireless networks owned and / or operated by other service providers.

[0041] Although the WTRU is described as a wireless terminal in Figures 1A to 1D, it is envisioned that in some representative embodiments, this terminal may be used with a communication network (e.g., temporarily or permanently) with a wired communication interface.

[0042] In a representative embodiment, other network 112 may be a WLAN.

[0043] In Basic Service Set (BSS) mode, a WLAN may have access points (APs) for the BSS and one or more stations (STAs) associated with the APs. APs may have access or interfaces to a Distribution System (DS) or another type of wired / wireless network that loads and / or loads traffic into and / or out of the BSS. Traffic originating outside the BSS and destined for STAs can reach and be delivered to those STAs via the AP. Traffic originating from STAs and destined for destinations outside the BSS can be sent to the AP for delivery to individual destinations. Traffic between STAs within the BSS can be sent via the AP, for example, where a source STA can send traffic to the AP and the AP can deliver traffic to the destination STA. Traffic between STAs within the BSS can be considered and / or referred to as peer traffic. Peer traffic can be sent between a source STA and a destination STA (e.g., directly between them) using a direct link setup (DLS). In some representative embodiments, the DLS can use 802.11e DLS or 802.11z tunneled DLS (TDLS). A WLAN using Independent BSS (IBSS) mode may not have an access point (AP), and STAs within the IBSS or using the IBSS (e.g., all STAs) can communicate directly with each other. The IBSS communication mode may sometimes be referred to herein as an "ad-hoc" communication mode.

[0044] When operating in 802.11ac infrastructure mode or a similar mode, the AP can transmit beacons on a fixed channel, such as the primary channel. The primary channel can be of fixed width (e.g., a 20 MHz bandwidth) or dynamically set via communication. The primary channel can be the operating channel of the BSS and can be used by STAs to establish connections with the AP. In some representative embodiments, Carrier Sense Multiple Access with Collision Avoidance (CSMA / CA) can be implemented, for example, in an 802.11 system. For CSMA / CA, STAs including the AP (e.g., each STA) can sense the primary channel. If the primary channel is sensed / detected and / or determined to be busy by a particular STA, that particular STA can go offline. A STA (e.g., only one station) can transmit at any given time within a given BSS.

[0045] High-throughput (HT) STAs can use 40 MHz wide channels for communication, for example, by combining a 20 MHz main channel with adjacent or non-adjacent 20 MHz channels to form a 40 MHz wide channel.

[0046] The Very High Throughput (VHT) STA supports channels of 20 MHz, 40 MHz, 80 MHz, and / or 160 MHz width. 40 MHz and / or 80 MHz channels can be formed by combining consecutive 20 MHz channels. A 160 MHz channel can be formed by combining eight consecutive 20 MHz channels, or by combining two non-consecutive 80 MHz channels (referred to as an 80+80 configuration). For the 80+80 configuration, after channel encoding, data can be transmitted through a segment parser that can divide the data into two streams. Inverse Fast Fourier Transform (IFFT) processing and time-domain processing can be performed separately on each stream. Streams can be mapped to two 80 MHz channels, and data can be transmitted via the transport STA. At the receiver receiving the STA, the above operation for the 80+80 configuration can be reversed, and the combined data can be sent to the Medium Access Control (MAC).

[0047] Sub-1 GHz operating modes are supported by 802.11af and 802.11ah. Channel operating bandwidth and carrier in 802.11af and 802.11ah are reduced 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 can support Meter Type Control / Machine-Type Communications, such as MTC devices in large coverage areas. MTC devices may have certain capabilities, such as limited capabilities including supporting (e.g., only supporting) certain and / or limited bandwidths. MTC devices may include battery packs with a battery pack life exceeding the critical limit (e.g., to maintain a very long battery pack life).

[0048] WLAN systems supporting multiple channels and channel bandwidths (such as 802.11n, 802.11ac, 802.11af, and 802.11ah) include a channel that can be designated as the primary channel. The primary channel can have a bandwidth equal to the maximum common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel can be set and / or limited by the STA supporting the minimum bandwidth operating mode among all STAs operating in the BSS. In the 802.11ah example, 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, the primary channel can be 1 MHz wide for STAs supporting (e.g., only supporting) the 1 MHz mode (e.g., MTC type devices). Carrier sensing and / or Network Allocation Vector (NAV) settings can depend on the status of the primary channel. For example, if the main channel is busy, for example because the STA (which only supports 1 MHz operating mode) transmits to the AP, even if most of the frequency band remains idle and available, the entire available frequency band can be considered busy.

[0049] In the United States, the available frequency band (which can be used by 802.11ah) ranges from 902 MHz to 928 MHz. In South Korea, the available frequency band ranges from 917.5 MHz to 923.5 MHz. In Japan, the available frequency band ranges from 916.5 MHz to 927.5 MHz. Depending on the country code, the total bandwidth available for 802.11ah ranges from 6 MHz to 26 MHz.

[0050] Figure 1D is a system diagram illustrating RAN 113 and CN 115 according to one embodiment. As mentioned above, RAN 113 may employ NR radio technology to communicate with WTRUs 102a, 102b, and 102c via air interface 116. RAN 113 may also communicate with CN 115.

[0051] RAN 113 may include gNBs 180a, 180b, and 180c, but it will be understood that RAN 113 may include any number of gNBs while remaining consistent with one embodiment. Each of gNBs 180a, 180b, and 180c may include one or more transceivers for communicating with WTRUs 102a, 102b, and 102c via air interface 116. In one embodiment, gNBs 180a, 180b, and 180c may implement MIMO technology. For example, gNBs 180a and 180b may utilize beamforming to transmit signals to and / or receive signals from gNBs 180a, 180b, and 180c. Therefore, gNB 180a, for example, may use multiple antennas to transmit radio signals to and / or receive radio signals from WTRU 102a. In one embodiment, gNBs 180a, 180b, and 180c may implement carrier aggregation technology. For example, gNB 180a can transmit multiple component carriers to WTRU 102a (not shown). A subset of these component carriers may be on unlicensed spectrum, while the remaining component carriers may be on licensed spectrum. In one embodiment, gNBs 180a, 180b, and 180c may implement Coordinated Multi-Point (CoMP) technology. For example, WTRU 102a may receive coordinated transmissions from gNB 180a and gNB 180b (and / or gNB 180c).

[0052] WTRUs 102a, 102b, and 102c can communicate with gNBs 180a, 180b, and 180c using transmissions associated with a scalable set of parameters (numerology). For example, OFDM symbol spacing and / or OFDM subcarrier spacing can vary for different transmissions, different cells, and / or different portions of the radio transmission spectrum. WTRUs 102a, 102b, and 102c can communicate with gNBs 180a, 180b, and 180c using subframes or transmission time intervals (TTIs) of various lengths or scalable lengths (e.g., containing a varying number of OFDM symbols and / or a continuously varying absolute time length).

[0053] gNBs 180a, 180b, and 180c can be configured to communicate with WTRUs 102a, 102b, and 102c in standalone and / or non-standalone configurations. In standalone configuration, WTRUs 102a, 102b, and 102c can communicate with gNBs 180a, 180b, and 180c without accessing other RANs (e.g., eNode-Bs 160a, 160b, and 160c). In standalone configuration, WTRUs 102a, 102b, and 102c can use one or more gNBs 180a, 180b, and 180c as operational anchors. In standalone configuration, WTRUs 102a, 102b, and 102c can use signals in unlicensed frequency bands to communicate with gNBs 180a, 180b, and 180c. In a non-independent configuration, WTRUs 102a, 102b, and 102c can communicate with / connect to gNBs 180a, 180b, and 180c, while also communicating with / connecting to another RAN (such as eNode-Bs 160a, 160b, and 160c). For example, WTRUs 102a, 102b, and 102c can implement DC principles to substantially simultaneously communicate with one or more gNBs 180a, 180b, and 180c and one or more eNode-Bs 160a, 160b, and 160c. In a non-independent configuration, eNode-B 160a, 160b, and 160c can act as action anchors for WTRU 102a, 102b, and 102c, and gNB 180a, 180b, and 180c can provide additional coverage and / or throughput for servicing WTRU 102a, 102b, and 102c.

[0054] Each of gNBs 180a, 180b, and 180c can be associated with a specific cell (not shown) and can be configured to handle radio resource management decisions, handover decisions, user scheduling in UL and / or DL, network slicing support, dual connectivity, interoperability between NR and E-UTRA, routing of user plane data to User Plane Function (UPF) 184a and 184b, routing of control plane information to Access and Mobility Management Function (AMF) 182a and 182b, and similar functions. As shown in Figure 1D, gNBs 180a, 180b, and 180c can communicate with each other via the Xn interface.

[0055] The CN 115 shown in Figure 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 may include Data Network (DN) 185a, 185b. Although each of the above elements is depicted as part of the CN 115, it will be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0056] AMF 182a and 182b can connect to one or more gNBs 180a, 180b, and 180c in RAN 113 via the N2 interface and can act as control nodes. For example, AMF 182a and 182b can be responsible for authenticating users of WTRU 102a, 102b, and 102c, supporting network slicing (e.g., handling different PDU conversations with different needs), selecting specific SMF 183a and 183b, managing login zones, terminating NAS communications, managing mobility, and similar functions. Network slices can be used by AMF 182a and 182b to customize the CN support for WTRU 102a, 102b, and 102c based on the type of service being used by the WTRU 102a, 102b, and 102c. For example, different network slices can be established for different use cases, such as services relying on ultra-reliable low latency (URLLC) access, services relying on enhanced massive mobile broadband (eMBB) access, services for machine type communication (MTC) access, and / or similar. AMF 162 can provide control plane functions for switching between RAN 113 and other RANs (not shown) that use other radio technologies (such as LTE, LTE-A, LTE-A Pro, and / or non-3GPP access technologies (such as WiFi)).

[0057] SMFs 183a and 183b can connect to AMFs 182a and 182b in CN 115 via the N11 interface. SMFs 183a and 183b can also connect to UPFs 184a and 184b in CN 115 via the N4 interface. SMFs 183a and 183b can select and control UPFs 184a and 184b and configure the routes for traffic passing through UPFs 184a and 184b. SMFs 183a and 183b can perform other functions, such as managing and allocating UE IP addresses, managing PDU conversations, controlling policy enforcement and QoS, providing downlink data notifications, and similar functions. PDU conversation types can be IP-based, non-IP-based, Ethernet-based, and similar.

[0058] UPF 184a and 184b can be connected via an N3 interface to one or more gNBs 180a, 180b, and 180c in RAN 113. This interface provides access to packet-switched networks (such as Internet 110) to WTRU 102a, 102b, and 102c to facilitate communication between WTRU 102a, 102b, and 102c and IP-enabled devices. UPF 184 and 184b can 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, and the like.

[0059] CN 115 can facilitate communication with other networks. For example, CN 115 may include an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that acts as an interface between CN 115 and PSTN 108, or be able to communicate with such an IP gateway. Additionally, CN 115 may provide WTRU 102a, 102b, 102c with access to other networks 112, such other networks may include other wired and / or wireless networks owned and / or operated by other service providers. In one embodiment, WTRU 102a, 102b, 102c may be connected to the local area data network (DN) 185a, 185b via the N3 interface to UPF 184a, 184b and the N6 interface between UPF 184a, 184b and DN 185a, 185b.

[0060] Based on the corresponding descriptions in Figures 1A to 1D, one or more of the functions described herein, or all of them, can be performed by one or more emulation devices (not shown): WTRU 102a to 102d, base stations 114a to 114b, eNode-B 160a to 160c, MME 162, SGW 164, PGW 166, gNB 180a to 180c, AMF 182a to 182b, UPF 184a to 184b, SMF 183a to 183b, DN 185a to 185b, and / or any other devices(s) described herein. Emulation devices can be configured to emulate one or more of the functions described herein. For example, emulation devices can be used to test other devices and / or simulate network and / or WTRU functions.

[0061] Simulation devices can be designed to perform one or more tests on other devices in a laboratory environment and / or an operator network environment. For example, one or more simulation devices can perform one or more or all of the functions of a wired and / or wireless communication network while being fully or partially implemented and / or deployed as part of a wired and / or wireless communication network to test other devices within the communication network. One or more simulation devices can perform one or more or all of the functions while being temporarily implemented / deployed as part of a wired and / or wireless communication network. Simulation devices can be directly coupled to another device for testing purposes and / or can use over-the-air wireless communication to perform tests.

[0062] One or more emulation devices can perform one or more (including all) functions while not being implemented / deployed as a wired and / or wireless communication network. For example, emulation devices can be used in test scenarios in test laboratories and / or non-deployed (e.g., test) wired and / or wireless communication networks to perform tests on one or more components. One or more emulation devices can be test instruments. Wireless communication via direct RF coupling and / or through an RF circuit system (e.g., which may include one or more antennas) can be used by the emulation device to transmit and / or receive data.

[0063] This document describes systems, methods, and instruments for sidelink (SL) collision detection and indication (e.g., in New Radio (NR) vehicle-to-everything (V2X) communication). A wireless transmit / receive unit (WTRU) may transmit resource reservations (e.g., in sidelink control information (SCI)). A receiving (RX) WTRU may receive SCIs from (e.g., multiple) transmitting (TX) WTRUs, where the TX WTRUs reserve resources for transmission. TX WTRUs may be unaware of other TX WTRUs (e.g., they may not know the resources reserved by other TX WTRUs). For example, if reserved resources overlap (e.g., partially or completely), the resources may be conflicting. For instance, a collision may occur if multiple TX WTRUs reserve conflicting resources for transmission and / or if a TX WTRU reselects a non-conflicting resource for transmission.

[0064] The RX WTRU (e.g., the first WTRU) may receive configuration information indicating the conflict detection processing time (e.g., the time used by the RX WTRU to determine the existence of a conflict and send a conflict indication). The RX WTRU may receive a first SCI from the first TX WTRU (e.g., the second WTRU). The first SCI may include an indication (e.g., a first indication) indicating a first resource, a first conflict indication setting, and a first priority value. The RX WTRU may receive an indication indicating, for example, the conflict indication processing time associated with the first TX WTRU. The RX WTRU may determine the conflict detection triggering timing (e.g., a time window in which the RX WTRU has sufficient time to detect a conflict and send a conflict indication (e.g., to the first TX WTRU), for example, based at least on the conflict detection processing time and the first resource. The conflict detection triggering timing may be determined, for example, based on the conflict detection processing time, the conflict indication processing time (e.g., associated with the first TX WTRU), and the first resource. The RX WTRU may receive a second SCI from a second TX WTRU (e.g., a third WTRU) during a collision detection triggering event, for example. The second SCI may include indications of a second resource, a second collision indication setting, and / or a second priority value (e.g., a second indication). The RX WTRU may determine that a collision exists associated with the first and second resources. For example, the RX WTRU may determine that a collision exists associated with the first and second resources based on a determination that a measurement associated with the second SCI (e.g., Reference Signal Received Power (RSRP)) is greater than a first threshold. For example, the RX WTRU may determine that a collision exists associated with the first and second resources based on a determination that the first and second resources overlap (e.g., partially or completely). The RX WTRU may send a collision indication, for example, to the first TX WTRU. The RX WTRU may send a collision indication to the first TX WTRU, for example, based on a determination that a first collision indication setting is enabled and a second collision indication setting is disabled. The RX WTRU may send a conflict indication to the first TX WTRU, for example, based on the determination that a first conflict indication setting is enabled, a second conflict indication setting is enabled, and a first priority value is greater than a second priority value.

[0065] The WTRU can detect conflicts in one or more aperiodic / periodic SL resources held by multiple Mode 2 WTRUs. For example, based on the priority, time and frequency assignment and retention interval period indicated in the SCI, conflict indication can be provided to (e.g., one) WTRU. SL conflict detection and indication methods may include one or more of the following.

[0066] For example, a WTRU may be configured with one or more of the following: a subset of WTRU source and / or destination IDs; SL priority thresholds (e.g., Prio thre); SL ​​CBR thresholds (e.g., CBR thre); conflict detection processing time (e.g., T proc); conflict indication transmission processing time (e.g., T PSICH); conflict detection enable / disable indications (e.g., ConflictDetEnabled); conflict indication enable / disable indications (e.g., ConflictIndEnabled); SL ​​conflict detection RSRP thresholds (e.g., RSRP conflict); PSICH format; and / or PSICH resource configuration.

[0067] The WTRU can receive resource reservations in the SCI from the first TX WTRU and / or can determine the collision detection triggering timing and / or the corresponding resource for detection based on one or more of the following: the number of resources reserved in the SCI; the configured collision detection processing time limit; the configured collision indication processing time limit; the time resource allocation indicated in the received SCI; and / or the resource reservation period indicated in the received SCI. The WTRU can determine the collision detection triggering timing for SP-type resource reservations that include multiple (e.g., two) retransmission resources.

[0068] WTRU may trigger conflict detection under determined conflict detection triggering conditions (e.g., determined to be) based on one or more of the following: priority order indicated in the received SCI and / or configured priority thresholds (e.g., Prio threshold); measured SL CBR and / or configured CBR thresholds (e.g., CBR threshold); ConflictDetEnabled indicated in the received SCI; RSRP; distance; TX WTRU power saving status; resource allocation scheme; TX WTRU type; decoding status; and / or HARQ feedback status.

[0069] The WTRU can detect collisions in one or more resources that have been determined to be collisions based on one or more of the following: RSRP thresholds configured; and / or RSRPs transmitted from the SCI of a second TX WTRU that is retained in the sensing of the same resource.

[0070] The WTRU may determine the TX WTRU and its corresponding (e.g., PSICH) format and information for conflict indication transmission (e.g., PSICH) based on one or more of the following: the priority indicated by the first and second TX WTRUs in the SCI; the resource reservation period indicated by the first and second TX WTRUs in the SCI; the enable / disable indication of the conflict indication (e.g., ConflictIndEnabled); and / or the configured PSICH format.

[0071] The WTRU may determine the resources transmitted via PSICH based, for example, on one or more of the following: configured PSICH resources; the source and / or destination ID of the determined TX WTRU; and / or the time and / or frequency resource allocation indicated in the SCI from the determined TX WTRU.

[0072] WTRU can transfer PSICH from a determined resource to a determined TX WTRU.

[0073] For example, a WTRU such as a receiver (RX) WTRU can, for instance, determine the triggering of conflict detection for one or more resources reserved in a received SL control information (SCI) associated with the (pre)configured WTRU information and / or destination identifier (ID) based on information indicated in the received SCI (e.g., L1 priority and time resources) and / or (pre)configuration parameters (e.g., channel busy ratio (CBR) and L1 priority threshold).

[0074] The RX WTRU can detect collisions and / or collision types, for example, based on SCI decoding in a set of SL time slots. SCI decoding can be determined, for example, based on reserved time resources, reference signal received power (RSRP) threshold configuration, and / or indicated resource reservation period. Collision types may include beamforming (e.g., FR2) operation, previously accepted SP-type reservations, SL / UL transmissions, multicast TX / RX collisions, and / or simultaneous partial overlap and corresponding prioritization and indication transmission-specific collisions.

[0075] An RX WTRU can determine that a TX WTRU is transmitting a Physical Side Link Indicator Channel (PSICH) transmission, and use the corresponding PSICH format and resource indication to perform resource reselection, periodic resource reselection, cancellation of retransmission, etc., for example, due to detected collisions.

[0076] TX WTRU behavior can be determined, for example, based on receiving PSICH transmissions according to PSICH information (e.g., including disabling resource preemption).

[0077] The WTRU can determine the PSICH power setting. The WTRU can determine the PSICH power setting, for example, by considering DL or SL path losses and parallel PSICH and PSFCH transmissions. The PSICH power setting can be used for PSICH transmissions or parallel PSICH and / or PSFCH transmissions. The WTRU can perform parallel PSICH and PSFCH transmissions, for example, by considering prioritization. Prioritization can be based on SL priority order (e.g., associated with PSICH and / or PSFCH transmissions).

[0078] The WTRU can (e.g., determine) perform collision information transmission. Collision information transmission may include information associated with a set of conflicting resources. Collision information transmission may include the WTRU source and / or destination IDs associated with that set of conflicting resources. The WTRU can perform collision information transmission, for example, to a TX WTRU. The TX WTRU can determine, for example, which sets of resources(s) should be used for transmission based on the collision information transmission WTRU source / destination IDs, Reference Signal Received Power (RSRP), or TX-RX distance. The TX WTRU can combine resources from the selected set in the resource selection window.

[0079] The behavior of the RX WTRU during SCI decoding can be determined, for example, based on resource information transmission to the TX WTRU. For instance, the RX WTRU can exclude (e.g., from decoding resource allocation) resource candidates (e.g., PSCCH resource candidates) from the resources provided to the TX WTRU (e.g., during resource information transmission). The RX WTRU can prioritize (e.g., during decoding) resource candidates (e.g., PSCCH resource candidates) if, for example, the resource candidates are within the resource groups (e.g., conflicting and non-conflicting) provided to the TX WTRU during resource information transmission.

[0080] It can enable and / or provide coordination between WTRUs. It can improve (e.g., in terms of reliability) resource allocation (e.g., mode 2 resource allocation). Mode 2 resource selection reliability can be affected by hidden nodes, exposed nodes, half-duplex and / or uplink (UL) / sidelink (SL) transmission overlap. Transmitter (TX) WTRUs (e.g., mode 2 TX WTRUs) can perform resource selection, such as based on sensing that may not detect problems. Multiple TX WTRUs can transmit simultaneously on the same time and frequency resources, which can lead to collisions. Persistent collisions may exist between semi-persistent reserved transmissions, which can degrade the reliability of vehicle-to-everything (V2X) services.

[0081] Coordination between WTRUs can mitigate one or more problems. Coordination enables the receiver (RX) WTRU to provide information to assist the TX WTRU in resource selection. Coordination or shared information may include, for example, a set of (e.g., explicit) resources that may be better or worse for transmissions from the TX WTRU. Coordination or shared information may include, for example, indications (e.g., implicit) of conflicts applicable to resources that can be reserved by the TX WTRU.

[0082] The program that enables coordination between WTRUs can be based on V2X design and / or multiple operating scenarios.

[0083] Conflict indication transmissions can lead to excessive communication overhead and congestion. SL control information (SCI) can reserve (e.g., additional) resources in subsequent SL time slots, for example, if (e.g., when) the RX WTRU is in the SL time slot. The SCI is received from the physical-side link control channel (PSSCH) of the TX WTRU and transmitted through the same time slot. Subchannel scheduling entity-side link shared channel (PSSCH) / PSCCH transmission. Reserved resources may include, for example, multiple (e.g., two) time slots for (e.g., the same) SL transmission block (TB) (e.g., = + T 1 and = + T 2) retransmission of resources. For example, if (e.g., when) the resource retention period (e.g., P rsvp_TX) is not equal to zero, one or more SL time slots (e.g., , and The resources reserved in ) can be used for the initial transfer and / or retransmission of (e.g., new) TB in SL time slots (e.g., +n* P rsvp_TX , +n* P rsvp_TX and +n* P rsvp_TX ) is reserved (e.g., periodically). Several neighboring WTRUs may exist, which can receive SCI and perform collision detection. WTRUs (e.g., each of the several WTRUs) can transmit (e.g., several) indication transmissions. For example, this can reduce communication overhead and congestion while improving reliability.

[0084] The processing capabilities of the WTRU can be improved (e.g., to overcome limitations) to detect, indicate, and / or act on conflicts for (e.g., all) resources reserved in (e.g., one) SCI. The WTRU can utilize (e.g., sufficient) time and processing to perform conflict detection (e.g., with high reliability) and prepare and transmit (e.g., subsequent) indications. A WTRU that receives indication transmissions to decode, process, and act on the indications can utilize more time. The WTRU can perform V2X Mode 2 sensing and resource selection processing to detect and indicate conflicts for (e.g., each) reserved resources (e.g., regardless of the type of resource in the time domain). The WTRU receiving the indication may have the capability, limited capability, or no capability to act on the indication. For example, a vulnerable road user (VRU) type WTRU may not have a receiver and / or be able to perform random resource selection.

[0085] WTRU can detect conflicts, for example, those indicated in the received SCI. Conflicts can be detected for SL resources. Conflict indication can be (pre)configured. WTRUs may receive (e.g., via higher-level (pre)configuration) configuration information such as one or more of the following (e.g., regarding SL resource conflict detection and indication): a subset of WTRU source and / or destination identifiers (IDs); SL ​​priority thresholds (e.g., Prio thre); SL ​​channel busy ratio (CBR) thresholds (e.g., CBR thre); conflict detection processing time (e.g., T proc); conflict indication transmission processing time (e.g., T PSICH); enable / disable indicators for WTRU coordination and / or conflict detection (e.g., ConflictDetEnabled); enable / disable indicators for WTRU coordination and / or conflict indication (e.g., ConflictIndEnabled); SL ​​conflict detection reference signal received power (RSRP) thresholds (e.g., RSRP conflict); and / or PSICH and / or PSFCH resource configurations for WTRU coordination and / or conflict detection.

[0086] The WTRU may receive configuration information indicating (e.g., through higher-level (pre)configuration) a pair of WTRU source and / or destination IDs, for example, for unicast SL transmission and / or reception. The WTRU may receive configuration information indicating (e.g., through higher-level (pre)configuration) a WTRU destination ID, for example, for multicast and / or unicast SL transmission and / or reception. The WTRU may receive configuration information (e.g., (pre)configured) one or more (e.g., a set) of WTRU source and / or destination IDs, for example, based on supported services (e.g., V2X services) and / or applications (e.g., V2X applications). In some instances, a subset of WTRU source and / or destination IDs may be indicated for use (e.g., (pre)configured) for SL resource conflict and / or indication. The WTRU may perform SL resource conflict detection and indication, for example, on resources reserved for SL transmissions associated with a subset of WTRU source and / or destination IDs.

[0087] In some instances, the WTRU can receive configuration information (e.g., pre-configured) of SL priority thresholds (e.g., Prio thre) in the SL resource pool. The WTRU can, for example, determine to trigger SL resource conflict detection and indication based on the (e.g., pre-configured) Prio thre at a resource conflict detection triggering event. SL priority thresholds can, for example, enable conflict detection and indication for SL transfers (e.g., with high priority).

[0088] In some instances, the WTRU can receive configuration information indicating (e.g., pre-configured) SL CBR thresholds (e.g., CBR thresholds) in the SL resource pool. The WTRU can, for example, trigger SL resource conflict detection and indication based on (e.g., pre-configured) CBR thresholds at a resource conflict detection trigger point (e.g., within a specified timeframe). SL CBR thresholds can mitigate increases in SL congestion, which may be caused by indication transmissions resulting from SL resource conflict detection.

[0089] The WTRU can receive configuration information indicating (e.g., pre-configured) a WTRU collision detection processing time threshold (e.g., T proc). The collision detection processing time threshold can correspond to the (e.g., minimum) time period required for the WTRU to perform collision detection (e.g., and transmit the resulting indication) (e.g., required). For example, the time threshold can be represented in several SL time slots. The value of the time threshold can be based on, for example, WTRU processing capacity and / or subcarrier spacing (SCS), e.g., the SCS associated with the SL bandwidth portion (BWP), e.g., the pre-configured SL bandwidth portion (BWP).

[0090] The WTRU can receive configuration information indicating (e.g., pre-configured) a WTRU conflict indication processing time threshold (e.g., T PSICH). The conflict indication processing time threshold can correspond to the (e.g., minimum) time period required by the WTRU to receive and decode the conflict indication (e.g., and perform the indicated operation, such as resource selection) (e.g., required). For example, the time threshold can be represented in several SL time slots. The value of the processing time threshold can be based on, for example, the WTRU processing capacity and / or SCS, such as the SCS associated with the SL BWP (e.g., pre-configured SL BWP).

[0091] In some instances, the RX WTRU may determine, for example, based on T proc and / or T PSICH, the timing of collision detection triggering for resources reserved in the received SCI from the TX WTRU (e.g., the latest collision detection triggering timing). The RX WTRU may trigger collision detection near reserved SL slots, for example, to capture as many conflicting SL resource reservations as possible. Conflicting SL resource reservations may be reservations of partially or completely overlapping subchannels within SL slots (e.g., the same SL slot). Collision detection triggering may occur, for example (e.g., early enough), to allow processing time for collision detection and indication transmission at the RX WTRU and indication reception and indication operations at the TX WTRU.

[0092] In some instances, the WTRU may receive (e.g., pre-configured) an enable / disable instruction (e.g., ConflictDetEnabled) for collision detection. The TX WTRU may include the ConflictDetEnabled instruction, for example, in the SCI of PSSCH / PSCCH transmission. For example, if (e.g., when) the instruction for collision detection is set to "Enabled", the RX WTRU may perform collision detection for resources reserved in the SCI. For example, if (e.g., when) the instruction for collision detection is set to "Disabled", the RX WTRU may avoid performing (e.g., not perform) collision detection for resources reserved in the SCI.

[0093] In some instances, the WTRU may receive (e.g., pre-configured) an enable / disable indicator (e.g., ConflictIndEnabled) for conflict indication. The TX WTRU may include the ConflictIndEnabled indicator, for example, in the SCI of PSSCH / PSCCH transmission. For example, if (e.g., when) the indicator for conflict indication is set to "Enabled", the RX WTRU may transmit the conflict indication to the TX WTRU for (e.g., dedicated to) resources reserved in the SCI. For example, if (e.g., when) the indicator for conflict indication is set to "Disabled", the RX WTRU may avoid (e.g., not perform) the transmission of the conflict indication to the TX WTRU that reserves resources in the SCI.

[0094] The ConflictDetEnabled and ConflictIndEnabled SCI indicators support WTRUs with limited or no receiving capabilities (e.g., VRUs without RX hardware (HW)). WTRUs (e.g., those with limited or no receiving capabilities) can perform random resource selection without sensing. The resulting SL transmissions can withstand high collisions. SL resource detection for randomly selected resources improves transmission reliability. For example, due to HW limitations, indicated transmissions can be avoided (e.g., not performed).

[0095] In some instances, the WTRU may receive configuration information indicating (e.g., pre-configured) the SL conflict detection RSRP threshold (e.g., RSRP conflict). The WTRU may, for example, determine the detected conflict in the reserved resource based on (e.g., pre-configured) RSRP conflict. For example, if (e.g., when) the measured RSRP is higher than the indicated (e.g., pre-configured SL) conflict detection RSRP threshold (e.g., RSRP conflict), the RX WTRU may determine that a conflict has been detected. The value of the (e.g., pre-configured) SL conflict detection RSRP threshold may depend on, for example, the priority indicated by different WTRUs in the SCI for reserving (e.g., the same) resource.

[0096] In an example, the WTRU can receive configuration information indicating (e.g., pre-configured) PSICH and / or PSFCH resources for WTRU inter-coordination and / or conflict detection. This resource configuration information can be associated with an SL resource pool (e.g., dedicated to it). If the PSICH and / or PSFCH resources are configured in the resource pool, the WTRU can determine, for example, that WTRU inter-coordination and / or conflict detection and indication are enabled, and the WTRU can perform WTRU inter-coordination and / or conflict detection for SL transmissions (e.g., using resources from the resource pool).

[0097] The RX WTRU can determine the timing of conflict detection for resources reserved in the received SCI. In some instances, the RX WTRU can determine the timing of entity-side link indicator channel (PSICH) transmissions based on, for example, the PSICH resource configuration of a resource pool, which can (e.g., at least) be located before the T PSICH before the reserved SL time slots of the reserved resources. The periodicity of the PSICH transmission timing (e.g., (pre)configuration) can be, for example, one per SL time slot, one per two SL time slots, one per four SL time slots, etc. The WTRU can determine the time offset (e.g., T offset) between the determined PSICH transmission timing and the reserved SL time slots. For example, if (e.g., when) the PSICH transmission periodicity is one per SL time slot, the T offset can also be set to be equal to T PSICH. For example, if (e.g., when) the PSICH transmission periodicity is one of every two SL time slots, for example, depending on the index of the reserved SL time slot, the T offset can be set to be equal to T PSICH or T PSICH + 1 (e.g., as shown in the examples in Figures 2A to 2D).

[0098] The RX WTRU can determine the (e.g., latest) conflict detection trigger timing corresponding to the reserved resource, which can (e.g., at least) be located before the determined PSICH transmission timing by T proc. The RX WTRU can (e.g., therefore) determine that the conflict detection trigger timing of the reserved resource can (e.g., at least) occur before the conflict-detected resource by (T proc + T offset).

[0099] Figures 2A to 2D illustrate examples of WTRU collision detection triggering timing for retransmission of resource reservation.

[0100] The RX WTRU can determine when to reserve resources for retransmission in the received SCI. The RX WTRU can determine the timing of collision detection in the SL time slot, for example, based on one or more of the following. The received SCI reserves one or more (e.g., the latest) collision detection timings for resources used for retransmission: collision detection processing time (e.g., T proc); collision indication transmission processing time (e.g., T PSICH); one or more PSICH transmission timings in the resource pool (e.g., (pre-)configured); the number of resources reserved in the received SCI; and the time slots used for SL (e.g., = The time resource allocation (e.g., T1) indicated in the received SCI for the resources reserved in + T1); and / or for SL time slots (e.g., = The time resource allocation (e.g., T2) indicated in the SCI received by the resources reserved in + T 2 ).

[0101] RX WTRU can be determined for use in SL time slots The received SCI retains one or more (e.g., the latest) conflict detection moments for resources to be retransmitted, for example, as described in one or more of the following examples. The (e.g., the latest) conflict detection moment may represent a time instance prior to when the WTRU could avoid triggering (e.g., not triggering) a conflict detection. The WTRU may trigger inter-WTRU coordination and / or conflict detection at a conflict detection moment (e.g., SL slot (SL slot n)), for example, prior to the determined (e.g., the latest) conflict detection moment. Triggering may be based on (e.g., (pre)configuration) conditions (e.g., as discussed herein).

[0102] In some instances, SL slots can be used. = + T 1 reserves (e.g., one) retransmission resource. As shown in the example in Figure 2A, T 1 >= T proc + T offset. RX WTRU can be determined to correspond to the SL time slot. SL slots for reserving and retransmitting resources = The latest conflict detection timing in + T 1 - T proc - T offset (e.g., if T 1 >= T proc + T offset). For example, if T 1 >= T proc + T offset, RX WTRU may (e.g., determine to) avoid performing (e.g., not perform) conflict detection for reserved resources.

[0103] In some instances, SL slots can be used. = + T 1 and = + T 2 retains multiple (e.g., two) retransmission resources. As shown in the example in Figure 2B, T 1 >= T proc + T offset_1 and T 2 - T 1 >= T proc + T offset_2. The RX WTRU can determine multiple (e.g., two most recent) conflict detection opportunities. The RX WTRU can determine a conflict detection opportunity in, for example, the slot corresponding to SL. SL time slots, which are reserved in the system = + T 1 - T proc - T offset_1. RX WTRU can determine a conflict detection timing, for example, corresponding to the SL time slot. SL time slots, which are reserved in the system = + T 1 - T proc - T offset_2 in.

[0104] In some instances, SL slots can be used. = + T 1 and = + T 2 retains multiple (e.g., two) retransmission resources. As shown in the example in Figure 2C, T 1 < T proc + T offset and T 2 - T 1 >= T proc + T offset. RX WTRU can be determined to correspond to the SL time slot. SL slots for reserving and retransmitting resources = + T 2 - T proc - T offset_2 Latest conflict detection timing. RX WTRU can avoid (e.g., not perform) SL time slots. Conflict detection for retransmitted resources.

[0105] In some instances, SL slots can be used. = + T 1 and = + T 2 retains multiple (e.g., two) retransmission resources. As shown in the example in Figure 2D, T 1 >= T proc + T offset and T 2 - T 1 < T proc + T offset. RX WTRU can be determined to correspond to the SL time slot. and SL slots for reserving and retransmitting resources = + T 1 - T proc - T offset_1 (e.g., latest) conflict detection timing. RX WTRU can execute SL slots. and SL slot Conflict detection for retransmitted resources.

[0106] In some instances, SL slots can be used. = + T 1 and = + T 2 reserves multiple (e.g., two) retransmission resources. For example, if T 1 < T proc + T offset and T 2 - T 1 < T proc + T offset, RX WTRU can (e.g., determine to) avoid performing (e.g., not perform) conflict detection of reserved resources.

[0107] The RX WTRU can determine several conflict detection opportunities in the received SCI for reserving resources for initial transmission and / or retransmission. For example, if the resource reservation period indicated in the SCI (e.g., Prsvp_TX) is greater than zero, the RX WTRU can receive the SL slot. Periodic resource reservation in SCI. In SL time slots. , and Reserved (e.g., identical) subchannels (e.g., if retransmission resources are reserved) can be used in SL time slots. + n* P rsvp_TX, + n* P rsvp_TX , and + n* P rsvp_TX . is reserved (e.g., periodically). The value of n can be 1 to N. For example, N can be the resource reselection value (e.g., configured by a higher level).

[0108] The RX WTRU can be determined, for example, based on one or more of the following factors for use in the SL time slot. The received SCI contains one or more (e.g., the latest) collision detection timings for resources reserved for (e.g., initial) transmission and / or retransmission: collision detection processing time (e.g., T proc); collision indication transmission processing time (e.g., T PSICH); one or more PSICH transmission timings (pre-configured) in the resource pool; the number of resources reserved in the received SCI; and the time slots used for SL. = + The time slot (e.g., T1) indicated in the SCI received by the resources reserved in T1; used for SL time slots = + The time interval indicated in the SCI received for the resources reserved in T 2 (e.g., T 2); and / or the resource retention period P rsvp_TX.

[0109] RX WTRU can determine (e.g., for a retention period, such as each retention period) whether to retain for use in the SL time slot. The timing of conflict detection for one or more (e.g., latest) resources retransmitted in the received SCI. One or more of the following may be applied.

[0110] Available in SL time slot + n* P rsvp_TX reserves (e.g., periodically) (e.g., one) initial resources, where P rsvp_TX >= T proc + T offset. For example, if in SL slot + n* P rsvp_TX and P rsvp_TX >= T proc + T reserve (e.g., periodically) initial resources, RX WTRU can be determined to correspond to SL time slot. + n* P rsvp_TX The reserved initial transfer SL slot in the (e.g., new) SL TB = + n* P rsvp_TX - T proc - T The timing of conflict detection in the offset (e.g., latest).

[0111] Available in SL time slot + n* P rsvp_TX reserves (e.g., periodically) (e.g., one) initial resources, where P rsvp_TX < T proc + T offset. For example, if in SL slot If an initial resource is reserved (e.g., periodically) in + n* P rsvp_TX and P rsvp_TX < T proc + T offset, RX WTRU can (e.g., determine to) avoid performing (e.g., not perform) conflict detection of the reserved resource.

[0112] For example, in the SL time slot = + n* P rsvp_TX and = + n* P rsvp_TX can retain (e.g., one) initial transfer and (e.g., one) retransmission resources. = + T 1), where P rsvp_TX >= T proc + T offset_1 and T 1 >= T proc + T offset_2. For example, if in SL slot = + n* P rsvp_TX and = + n* P rsvp_TX reserves (e.g., periodically) an initial transfer and (e.g., a) retransmission resource. = + T 1 ) and P rsvp_TX >= T proc + T offset_1 and T 1 >= T proc + T offset_2 ., RX WTRU can determine multiple (e.g., two latest) conflict detection opportunities. RX WTRU can determine multiple (e.g., two) latest conflict detection opportunities, where one of the latest conflict detection opportunities includes the one corresponding to the SL slot. + n* P rsvp_TX reserves the SL time slot = + n* P rsvp_TX - T proc - T offset_1 in the collision detection timing. RX WTRU can determine multiple (e.g., two) latest collision detection timings, one of which includes the collision detection timing corresponding to the SL slot. + n* P rsvp_TX reserves the SL time slot = + n* P rsvp_TX + T 1 - T proc - T offset_2 in the collision detection timing.

[0113] For example, in the SL time slot = + n* P rsvp_TX and = + n* P rsvp_TX can retain (e.g., one) initial transfer and (e.g., one) retransmission resources. = + T 1), where P rsvp_TX < T proc + T offset_1 and T 1 >= T proc + T offset_2. For example, if in SL slot = + n* P rsvp_TX and = + n* P rsvp_TX periodically reserves (e.g., an initial transfer) and (e.g., a retransmission resource). = + T 1 ) and P rsvp_TX < T proc + T offset_1 and T 1 >= T proc + T offset_2 , RX WTRU can be determined to correspond to the SL time slot. + n* P rsvp_TX Reserved retransmission resource SL slot = + n* P rsvp_TX + T 1 - T proc - T offset_2 (e.g., latest) conflict detection timing. RX WTRU can avoid (e.g., not perform) SL slots. Conflict detection for reserved retransmission resources in + n* P rsvp_TX.

[0114] For example, in the SL time slot = + n* P rsvp_TX and = + n* P rsvp_TX can retain (e.g., one) initial transfer and (e.g., one) retransmission resources. = + T 1), where P rsvp_TX >= T proc + T offset_1 and T 1 < T proc + T offset_2. For example, if in SL slot = + n* P rsvp_TX and = + n* P rsvp_TX can retain (e.g., one) initial transfer and (e.g., one) retransmission resources. = + T 1 ) and P rsvp_TX >= T proc + T offset_1 and T 1 < T proc + T offset_2 .,RX WTRU can be determined to correspond to the SL time slot. + n* P rsvp_TX and + n* P rsvp_TX Reserved retransmission resource SL slot = + n* P rsvp_TX - T proc - T offset_1 latest conflict detection timing. RX WTRU can perform conflict detection on reserved retransmission resources in two SL time slots (e.g., at one conflict detection timing).

[0115] For example, in the SL time slot = + n* P rsvp_TX and = + n* P rsvp_TX can retain (e.g., one) initial transfer and (e.g., one) retransmission resources. = + T 1 ), where P rsvp_TX < T proc + T offset_1 and T 1 < T proc + T offset_2 . For example, if in SL slot = + n* P rsvp_TX and = + n* P rsvp_TX reserves (e.g., periodically) an initial transfer and (e.g., a) retransmission resource. = + T 1 ), where P rsvp_TX < T proc + T offset_1 and T 1 < T proc + T offset_2 ., RX WTRU may (e.g., determine to) avoid performing (e.g., not perform) reserved resources (e.g., either one).

[0116] For example, if / when it is determined that such semi-persistent resources are reserved (e.g., if in SL slots) = + n* P rsvp_TX reserves (e.g., periodically) an initial transfer and (e.g., a) retransmission resource. = For the (e.g., latest) conflict detection triggering timing of + T 1), the RX WTRU can avoid considering (e.g., not considering) the time gap (T 1) between the initial transmission and retransmission. For example, if P rsvp_TX>= T proc+ T offset, the RX WTRU can determine the (e.g., latest) conflict detection timing in the SL slot y trig_n= y 0+ n*P rsvp_TX- T proc- T offset, which can correspond to the (e.g., new) SL TB initial transmission in the SL slot y 0+ n*P rsvp_TX and the (e.g., two) resources reserved for its retransmission in the SL slot y 1= y 1+ n*P rsvp_TX.

[0117] If, in the SL time slots y0 = y0 + n*P rsvp_TX, y1 = y1 + n*P rsvp_TX and y2 = y2 + n*P rsvp_TX, (e.g., periodically) an initial transfer and multiple (e.g., two) retransmission resources (y1 = y0 + T1 and y2 = y0 + T2) are reserved (e.g., periodically), and if P rsvp_TX >= T proc + T offset_1 and T1 >= T proc + T offset_2 and T2 >= T proc + T offset_3, the RX WTRU can determine multiple (e.g., three) latest conflict detection opportunities. In this example, the RX WTRU can determine the latest conflict detection event (e.g., one of several) in the SL time slot y trig_n_1 = y 0 + n*P rsvp_TX - T proc - T offset_1, which may correspond to a resource reserved in the SL time slot y 0 + n*P rsvp_TX. The RX WTRU can also determine the latest conflict detection event (e.g., one of several) in the SL time slot y trig_n_2 = y 0 + n*P rsvp_TX + T 1 - T proc - T offset_2, which may correspond to a resource reserved in the SL time slot y 1 + n*P rsvp_TX. RX WTRU can determine the latest conflict detection timing (e.g., one of multiple) in SL time slot y trig_n_3 = y 0 + n*P rsvp_TX + T 2 - T proc - T offset_3, which corresponds to the resource reserved in SL time slot y 1 + n*P rsvp_TX.

[0118] If, in slots y0 = y0 + n*P rsvp_TX, y1 = y1 + n*P rsvp_TX, and y2 = y2 + n*P rsvp_TX, (e.g., periodically) an initial transfer and multiple (e.g., two) retransmission resources (y1 = y0 + T1 and y2 = y0 + T2) are reserved (e.g., periodically), and if P rsvp_TX < T proc + T offset_1 and T1 < T proc + T offset_2 and T2 < T proc + T offset_3, the RX WTRU can determine to avoid performing (e.g., not performing) (e.g., either) conflict detection of the reserved resources.

[0119] For example, if (e.g., when) it is determined (e.g., such as) (e.g., semi-persistent) resource reservation (e.g., if in SL time slots y0 = y0 + n*P rsvp_TX, y1 = y1 + n*P rsvp_TX and y2 = y2 + n*P rsvp_TX) (e.g., periodically) (e.g., one initial transmission and two retransmission resources (y1 = y0 + T1 and y2 = y0 + T2)) the latest conflict detection timing, the RX WTRU can avoid considering (e.g., not considering) the time gap between the initial and retransmissions (e.g., T1, T2). If P rsvp_TX >= T proc + T offset (e.g., and the initial transfer and two retransmission resources are reserved as described herein), the RX WTRU can determine the latest conflict detection timing in the SL slot y trig_n = y 0 + n*P rsvp_TX - T proc – T offset, which can correspond to the initial transfer of (e.g., a new) SL TB in the SL slot y 0 + n*P rsvp_TX and the multiple (e.g., three) resources reserved for its retransmission in the SL slots y 1 = y 1 + n*P rsvp_TX and SL slots y 2 = y 2 + n*P rsvp_TX.

[0120] The RX WTRU may (e.g., determine) trigger conflict detection at (e.g., determined) conflict detection triggering time. For example, before the determined (e.g., latest) conflict detection triggering time (e.g., corresponding to the resource reserved in the SCI received in SL slot y 0), the RX WTRU may (e.g., determine) trigger conflict detection in SL slot (e.g., slot n). The determination of whether to trigger conflict detection may be based on one or more of the following: a subset of WTRU source and / or destination IDs; SL priority thresholds (e.g., Prio threshold); SL ​​CBR thresholds (e.g., CBR threshold); enable / disable indicators used for WTRU coordination and / or conflict detection (e.g., ConflictDetEnabled); PSICH / PSFCH resource configuration information; SL RSRP of the PSCCH carrying the SCI in SL slot y_0; the distance between the TX WTRU and RX WTRU using the area ID and the minimum communication requirement (MCR) indicated in the SCI received in SL slot y_0 (e.g., SL dedicated to transmission in reserved resources). TB); SL ​​power saving status indication (e.g., indicated in the SCI received in SL time slot y_0); resource allocation scheme (e.g., indicated in the SCI received in SL time slot y_0); WTRU type indication (e.g., indicated in the SCI received in SL time slot y_0); decoding status and / or HARQ feedback status of PSSCH transmissions in resources reserved in the SCI received in SL time slot y_0; and / or (e.g., explicit) requests from TX WTRUs for WTRU coordination and / or collision detection.

[0121] In some instances, for example, the RX WTRU may receive configuration information indicating (e.g., pre-configured, e.g., by a higher layer) a subset of WTRU source / destination IDs for SL resource conflicts and indications. The RX WTRU may receive resource reservations in the SCI transmitted via PSSCH / PSCCH. For example, if (e.g., when) the WTRU source and / or destination IDs indicated in the received SCI are within the indicated (e.g., pre-configured) subset, the RX WTRU may (e.g., determine to) trigger conflict detection.

[0122] In some instances, the WTRU can receive configuration information indicating (e.g., pre-configured) SL priority thresholds (e.g., Prio thresholds) in the SL resource pool. The RX WTRU can receive resource reservations in the SCI transmitted via PSSCH / PSCCH. For example, if (e.g., when) the priority indicated in the received SCI is higher than the (pre-configured) SL priority threshold, the RX WTRU can (e.g., determine to) trigger conflict detection.

[0123] The WTRU can receive configuration information indicating (e.g., pre-configured) the SL CBR threshold (e.g., CBR threshold) in the SL resource pool. The RX WTRU can receive resource reservations in the SCI transmitted via PSSCH / PSCCH. For example, if (e.g., when) the CBR measured at the time of resource conflict detection triggering is lower than the (pre-)configured SL CBR threshold, the RX WTRU can (e.g., determine to) trigger conflict detection.

[0124] In some instances, the WTRU can receive configuration information indicating (e.g., pre-configured) an enable / disable indicator (e.g., ConflictDetEnabled) for conflict detection. The RX WTRU can receive resource reservations in the SCI transmitted via PSSCH / PSCCH. For example, if (e.g., when) the ConflictDetEnabled indicator in the received SCI is set to "Enabled", the RX WTRU can (e.g., determine to) trigger conflict detection.

[0125] The RX WTRU can receive configuration information (e.g., a (pre)configured) resource pool (e.g., including PSICH / PSFCH resources). The presence of PSICH / PSFCH resources in the (pre)configured resource pool can indicate the ability to coordinate between WTRUs and / or enable conflict detection in the transmission of resources using the resource pool. For example, if (e.g., when) reserved resources are included in the resource pool (e.g., with PSICH / PSFCH resource configuration), the RX WTRU can determine to trigger conflict detection for the reserved resources.

[0126] For example, if (e.g., when) the measured SL RSRP of the PSCCH of the SCI of a resource in slot y_0 carrying a reserved SL exceeds the (pre)configured SL RSRP threshold, the RX WTRU can determine that conflict detection of the reserved resource is triggered. In an example, the WTRU can receive configuration information indicating (e.g., pre)configured) a set of SL RSRP threshold values ​​and (e.g., each) SL RSRP threshold (e.g., from that set of SL RSRP threshold values) that can be associated with SL priority order. The RX WTRU can determine the SL RSRP threshold corresponding to the L1 priority value indicated in the SCI of the reserved resource used for conflict detection.

[0127] In an example, if (e.g., when) the TX-RX distance does not exceed the MCR indicated in the SCI of the reserved resource used for collision detection, the RX WTRU may determine to trigger collision detection for the reserved resource. In an example, the WTRU source and / or destination ID indicated in the SCI transmitted by the TX WTRU may be associated with the V2X service and / or SL application subscribed to by the RX WTRU. The RX WTRU may determine the geographic location of the TX WTRU indicated by the area ID of the received TX WTRU (e.g., as the center of a geographic area), and may calculate the TX-RX distance, for example, based on the geographic locations of the TX WTRU and the RX WTRU.

[0128] For example, if (e.g., when) an SL power-saving state indication (e.g., included in a reserved resource SCI) indicates a state of reduced power consumption, the RX WTRU can (e.g., determine to) avoid triggering (e.g., not triggering) conflict detection for the reserved resource. For instance, the TX WTRU may be in a power-saving state where sensing and / or receiving are limited or disabled. The TX WTRU may disable resource reselection in the power-saving state, for example, to reduce power consumption. The TX WTRU may indicate such a power-saving state in a resource reservation included in the SCI, and the RX WTRU can (e.g., determine to) avoid triggering (e.g., not triggering) conflict detection for such SL transmissions.

[0129] In one instance, for example, if (e.g., when) the SCI for reserved resources indicates a random and / or partial resource selection scheme, the RX WTRU can (e.g., determine to) avoid triggering (e.g., not triggering) conflict detection for reserved resources. In another instance, the TX WTRU can (e.g., randomly) select resources for SL transmissions, such as not performing sensing. This can be attributed to power saving and / or HW limitations, such as having only a TX WTRU without an RX HW. In yet another instance, the TX WTRU can perform partial sensing for SL transmissions, and the RX WTRU can (e.g., pre-configured to) avoid triggering (e.g., not triggering) conflict detection for such transmissions.

[0130] In an example, if the SCI of a reserved resource indicates (e.g., pre-configured) a WTRU type, the RX WTRU can (e.g., determine to) avoid (e.g., not trigger) conflict detection for the reserved resource. Such (e.g., pre-configured) WTRU types may include vulnerable road users (VRUs), low-power wearable devices, and / or WTRUs with limited HW capabilities. The RX WTRU can (e.g., pre-configured to) avoid triggering (e.g., not triggering) conflict detection for SL transmissions performed by this type of WTRU.

[0131] For example, based on the decoding status and / or HARQ feedback status of the PSSCH transmission received in the resources reserved in the SCI received in slot y0 of SL (e.g., if / when HARQ is enabled), the RX WTRU can (e.g., determine to) trigger conflict detection for the reserved resources. The RX WTRU can receive configuration information indicating (e.g., pre-configured) thresholds for decoding CRC errors and / or HARQ NACKs. For example, if (e.g., when) the decoding CRC error and / or HARQ NACK of the PSSCH transmission received in the resources reserved in the SCI received in slot y0 of SL exceeds the (pre-)configured threshold, the RX WTRU can (e.g., determine to) trigger conflict detection. In an example, the RX WTRU may receive PSSCH transmissions in (e.g., semi-persistent) reserved resources in SL time slots y0+n*P rsvp_TX, y1+n*P rsvp_TX and y2+n*P rsvp_TX, where n may be from 1 to N and N may be a resource reselection value (e.g., indicated and / or (pre)configured by a higher layer).

[0132] In an example, if (e.g., when) the RX WTRU receives a (e.g., explicit) request from the TX WTRU, the RX WTRU may (e.g., determine to) trigger inter-WTRU coordination and / or conflict detection. The (e.g., explicit) request may include the WTRU source and / or destination ID associated with a V2X service and / or SL application (e.g., subscribed to by the RX WTRU). The RX WTRU may (e.g., determine to) trigger inter-WTRU coordination and / or conflict detection for received resource reservations (e.g., based on the received request), including, for example, (e.g., explicit) the WTRU source and / or destination ID indicated in the request.

[0133] Figure 3 illustrates an example of an RX WTRU performing conflict detection and conflict indication.

[0134] The RX WTRU can detect collisions based on triggering (e.g., when triggered) (e.g., determining that a condition is met). The RX WTRU can determine a collision, for example, due to detected overlapping resource reservations (e.g., as shown in Figure 3). The RX WTRU can determine that collision detection in SL slot n has been triggered (e.g., a condition has been met). For example, the RX WTRU can (e.g., based on the triggering of collision detection in SL slot n) process a set of decoded SCI and / or RSRP measurements in the sub-channel and / or SL slot to determine whether a collision is detected in the reserved resources used for collision detection. SL collision detection may include, for example, one or more of the following (e.g., performed by the RX WTRU): determining one or more collision detection parameters; performing SCI decoding; determining overlap of reserved resources; determining collision detection based on overlapping reservations; and / or determining the type of detected collision.

[0135] The RX WTRU can determine one or more collision detection parameters. One or more (e.g., collision detection) parameters can be indicated in the received configuration information (e.g., (pre)configuration, e.g., by a higher layer)) such as one or more of the following parameters: SL collision detection RSRP threshold (e.g., RSRP collision); collision detection window (e.g., T window, such as 1000 SL time slots); demodulation variable reference signal (DM-RS) used for measurement (e.g., PSCCH DM-RS or PSCCH DM-RS); and / or a set of resource reservation periods (e.g., P'rsvp_TX, such as 10 SL time slots, 20 SL time slots, etc.). One or more (e.g., collision detection) parameters may be indicated in the SCI (e.g., from the reserved TX WTRU) of resources in the reserved SL slot (e.g., SL slot y) for collision detection, such as one or more of the following parameters: L1 priority (e.g., prio TX_1), which is indicated in the received SCI and / or associated with the WTRU source and / or destination ID (e.g., due to the V2X services and / or applications supported by the RX WTRU); the number of reserved subchannels (e.g., ; and / or resource retention period (e.g., P rsvp_TX_1 ).

[0136] The RX WTRU can perform SCI decoding in the sub-channels of the resource pool in each SL slot (e.g., all) within the conflict detection window (e.g., from SL slot (n-T window) to SL slot (n)).

[0137] For example, if (for example, when) the SCI decoded in the SL time slot includes the SCI in the time slot (y) For partially or fully overlapping subchannels, the RX WTRU can determine the overlap of reserved resources. An SL time slot can be, for example, any SL time slot within the range from SL time slot (y-32) to SL time slot (y). An SL time slot may include SCI transmissions reserved for retransmissions, which may overlap with reserved resources in SL time slot (y). An SL time slot may be, for example, any SL time slot, which is the q*P'rsvp_TX time slot preceding SL time slot (y). In some instances, P'rsvp_TX may be, for example, any (pre)configured resource reservation period and / or q may be a non-zero positive integer. An SL time slot may include SCI transmissions reserved for periodic resources, which may overlap with reserved resources in SL time slot (y).

[0138] For example, the RX WTRU can determine a collision detection based on the overlap retention in the decoded SCI and / or the RSRP measured on a (e.g., a pre-configured) DM-RS (e.g., a PSCCH or PSSCH DM-RS) associated with the decoded SCI. For example, the RX WTRU can determine a collision detection if (e.g., when) the measured RSRP is higher than the indicated (e.g., a pre-configured SL) collision detection RSRP threshold (e.g., an RSRP collision). For instance, an RSRP collision can be calculated based on the indicated L1 priority in multiple (e.g., two) SCIs for retaining overlapping resources (e.g., prio TX_1 and prio TX_2).

[0139] Based on one or more of the following, the RX WTRU can determine the type of detected conflict (e.g., one-off or periodic conflict): resource reservation period (e.g., P rsvp_TX_1), which can be indicated in the SCI (e.g., by a reserved TX WTRU); and / or resource reservation period (e.g., P rsvp_TX_2), which can be indicated in the SCI (e.g., including overlapping resource reservations), for example, by a conflicting TX WTRU.

[0140] In some instances, P rsvp_TX_2 = 0 and / or P rsvp_TX_1 = 0. The RX WTRU can determine that the detected collision is the result of aperiodic transmissions (e.g., and may occur once), where the detected collision may be a one-off collision (e.g., if P rsvp_TX_2 = 0 and / or P rsvp_TX_1 = 0). In some instances, P rsvp_TX_1 and P rsvp_TX_2 > 0 and P rsvp_TX_1 = m * P rsvp_TX_2 or P rsvp_TX_2 = m * P rsvp_TX_1 (e.g., where m is a non-zero positive integer). The RX WTRU can determine that a detected collision is the result of periodic transmissions (e.g., and can occur periodically), where the detected collision is a periodic collision, for example, if P rsvp_TX_1 and P rsvp_TX_2 > 0 and P rsvp_TX_1 = m * P rsvp_TX_2 or P rsvp_TX_2 = m * P rsvp_TX_1. Periodic collisions can lead to continuous collisions between periodic transmissions.

[0141] For example, if (e.g., when) multiple resources exist (e.g., as shown in the example in Figure 2D), the RX WTRU can perform conflict detection for (e.g., each) reserved resources that may be included in the triggered conflict detection (e.g., as described herein).

[0142] The RX WTRU can determine conflicts within the same time slot, for example, due to overlapping resource reservations. In an example, the RX WTRU can perform conflict detection for resources reserved within the same time slot (e.g., SL time slot y0, where an SCI that can receive reserved resources). Conflict detection can be based on parameters indicated in the decoded resource reservations received (e.g., each) in SL time slot y0. Parameters may include the WTRU source and / or destination IDs, and / or the number of reservations for subchannels (L subCHs).

[0143] For example, an RX WTRU may determine that a collision has been detected in SL slot y0 if (for example, when) both of the following occur: SCI indications decoded from multiple (for example, two or more) PSCCHs in SL slot y0 (for example, at least) overlap reservations on (for example, one) subchannels reserved for PSSCH transmissions in the same SL slot; and the WTRU source and / or destination IDs indicated in the overlapped resource reservations are associated with the V2X service and / or SL application subscribed to by the RX WTRU.

[0144] In an example, for instance, an RX WTRU may determine that a collision has been detected in SL slot y0 if (for example, when) both of the following occur: the SCIs decoded from multiple (e.g., two or more) PSCCHs in SL slot y0 indicate the same WTRU source and / or destination IDs dedicated to multicast transmissions; and the WTRU source and / or destination IDs indicated in the reservation are associated with the V2X service and / or SL application subscribed to by the RX WTRU.

[0145] The RX WTRU can determine conflicts arising from previously received resource reservations. In an example, the WTRU can determine a conflict based on previously received semi-persistent resource reservations and resource reservations that trigger conflict detection (e.g., based on the triggering of conflict detection in slot n of SL). The WTRU can perform one or more of the following associated with conflict detection.

[0146] The RX WTRU can determine conflict detection parameters, such as one or more of the following: parameters indicated in the SCI of a resource in an SL slot (e.g., SL slot y) reserved for conflict detection (e.g., from a reserved TX WTRU); and / or parameters indicated in an SCI previously received in a semi-persistent resource reservation from another TX WTRU.

[0147] The parameters indicated in the SCI of the resource in the reserved SL slot (e.g., SL slot y) for collision detection (e.g., from the reserved TX WTRU) may include the number of reserved subchannels (L subCH_1), the resource reservation period (P rsvp_TX_1), and / or the TCI status of the transmission in the reserved resource (TCI 1).

[0148] The RX WTRU can determine collision detection parameters, such as those indicated in a SCI previously received in a semi-persistent resource reservation from another TX WTRU. The WTRU source and / or destination ID indicated in such an SCI may be (e.g., pre-configured) among IDs received by the RX WTRU. Parameters indicated in an SCI previously received in a semi-persistent resource reservation from another TX WTRU may include the number of reserved subchannels (L subCH_2), the reserved SL time slots, the resource reservation period (e.g., P rsvp_TX_2) and P rsvp_TX_2 > 0, and / or the TCI status of the transmission in the reserved resource (TCI 2).

[0149] For example, if (e.g., when) there is a previously received resource reservation in time slot (y) (e.g., another TX WTRU may have a reserved SL time slot that overlaps with time slot (y)) and one or more of the following conditions exist, the RX WTRU may determine that a conflict has been detected: the reserved subchannel (e.g., partially or completely) overlaps with the L subCH in time slot (y); or the receive spatial domain filter systems associated with TCI 1 and TCI 2 are spatially orthogonal (e.g., the RX WTRU cannot receive both using an RX beam).

[0150] For example, based on the first resource reservation period indicated in the SCI by the reserved TX WTRU (e.g., P rsvp_TX_1) and / or the second resource reservation period indicated in the SCI including overlapping resource reservations by the conflicting TX WTRU (e.g., P rsvp_TX_2), the RX WTRU can determine the type of the detected conflict (e.g., one-off or periodic conflict). In an example, for instance, if (e.g., when) P rsvp_TX_1 and P rsvp_TX_1 = m * P rsvp_TX_2 or P rsvp_TX_2 = m * P rsvp_TX_1 (e.g., where m is a non-zero positive integer), the RX WTRU can determine that the detected conflict is the result of periodic transmissions and can occur periodically, and that the detected conflict can be a periodic conflict. Periodic conflicts can lead to continuous collisions between periodic transmissions.

[0151] In an example, if m is less than the (pre)configured threshold, the RX WTRU can determine that the detected conflict is a periodic conflict. For example, if m equals one, the reserved resources can overlap in each reservation period. For example, if m equals two, the reserved resources can overlap every two reservation periods.

[0152] The RX WTRU can determine a conflict, for example, based on (e.g., due to) its scheduled SL or UL transmission. In an example, the RX WTRU can determine a conflict if (e.g., when) the WTRU source and / or destination ID indicated in the SCI indicating that the resource is reserved in time slot (y) by one of the following transmissions by the RX WTRU is associated with the V2X service and / or SL application subscribed to by the RX WTRU: an SL transmission scheduled in time slot (y) by the network (e.g., gNB) based on SL mode 1 resource allocation, an SL transmission reserved in time slot (y) by the RX WTRU based on SL mode 2 resource allocation, and / or a UL transmission scheduled in time slot (y) by the network (e.g., gNB). The RX WTRU can avoid (e.g., be unable to) receive in the time slot of its transmission (e.g., due to half-duplex limitations of SL operation).

[0153] The WTRU can transmit resource conflict indications (e.g., in PSICH transmission, as shown in Figure 3). The RX WTRU can determine the TX WTRU and / or corresponding information used for PSICH transmission. For example, if (e.g., when) conflict detection is triggered according to a conflict detection triggering time and a conflict is detected (e.g., as shown in Figure 3), the RX WTRU can determine the TX WTRU to which the PSICH transmission is intended. The conflict detection triggering time may include a time window, where the RX WTRU has sufficient time to detect the conflict and send a conflict indication, for example, to the TX WTRU. The resource to which a conflict is detected at the corresponding conflict detection triggering time can be referred to as the conflicting resource. (For example, the determination used to transmit PSICH to a TX WTRU) can be based on one or more of the following: indicating one or more L1 priority orders in the SCI of the reserved overlapping resources (e.g., prio TX_1 and prio TX_2); enable / disable indicators for WTRU coordination and / or conflict detection (e.g., ConflictDetEnabled); enable / disable indicators for WTRU coordination and / or conflict indication (e.g., ConflictIndEnabled); SL ​​CBR threshold (e.g., CBR threshold); decoding results of PSSCH transmissions associated with the reserved resource SCI; the type of conflict detected (e.g., one-off or periodic); the WTRU source and / or destination ID indicated in the reserved conflicting resource SCI; the SL power saving indicator indicated in the reserved conflicting resource SCI; the WTRU type indicator indicated in the reserved conflicting resource SCI; the resource allocation scheme indicated in the reserved conflicting resource SCI; the SL of the PSCCH transmission carrying the reserved conflicting resource SCI. RSRP; and / or the distance between RX WTRU and TX WTRU that preserve conflicting resources.

[0154] For example, based on the L1 priority indication in the SCI (e.g., carried in the PSCCH transmission, as shown in Figure 3), the RX WTRU can determine the TX WTRU and / or corresponding information for the PSICH transmission. For example, based on the L1 priority indicated in the received SCI for reserved resources (e.g., prio TX_1) and / or based on the L1 priority indicated in the decoded SCI including overlapping resource reservations (e.g., prio TX_2), the RX WTRU can determine which TX WTRU to transmit the PSICH to. The RX WTRU can (e.g., determine) transmit the PSICH to a TX WTRU with a lower priority, such as a lower L1 priority (e.g., as shown in Figure 3). An RX WTRU may transmit a PSICH transfer (e.g., triggered by a conflict detection RX WTRU) to a TX WTRU (e.g., a conflicting TX WTRU, as shown in an example in Figure 4B), where the conflicting TX WTRU requests to reserve resources that overlap with already reserved resources (e.g., resources already reserved by a reserved TX WTRU, as shown in an example in Figure 4B). For example, if (e.g., when) prio TX_1 < prio TX_2 (e.g., prio TX_1 indicates a higher priority in Figure 4B, e.g., a lower value of prio can indicate a higher priority), the RX WTRU may transmit a PSICH transfer to the conflicting TX WTRU. An RX WTRU may also transmit a PSICH transfer (e.g., triggered by a conflict detection RX WTRU) to a TX WTRU that transmits a reserved resource, which triggers the RX WTRU to detect a conflict (e.g., a reserved TX WTRU, as shown in an example in Figure 4A). For example, if (e.g., when) prio TX_1 < prio TX_2 (e.g., prio TX_1 indicates a lower priority in Figure 4A, or a higher value of prio can indicate a lower priority), the RX WTRU can transmit a PSICH transmission to the reserved TX WTRU. Upon receiving a resource reservation from a conflicting TX WTRU, the RX WTRU can detect a conflict trigger. The RX WTRU can detect a conflict trigger at an offset time from the time of receiving the resource reservation from the conflicting TX WTRU (e.g., as shown in Figures 4A and 4B), for example, due to the conflict detection processing time associated with the RX WTRU. The PSICH transmission may include an indication to reselect a different resource. For example, if (e.g., when) the CBR measured at the time of resource conflict detection trigger is higher than (e.g., (pre)configured) SL CBR threshold, the RX WTRU can (e.g., with equal L1 priority) determine to avoid sending (e.g., not send) a PSICH transmission.For example, an RX WTRU can (e.g., with equal L1 priority) randomly select a TX WTRU to perform a PSICH transmission. For example, if (e.g., when) collision detection includes multiple (e.g., two) reserved resources and / or collisions are detected in each of the multiple resources, the RX WTRU can transmit simultaneous PSICH transmissions to both the reserved and conflicting TX WTRUs at the same PSICH transmission time. The RX WTRU can perform TX power sharing between simultaneous PSICH transmissions.

[0155] Figures 4A to 4C illustrate examples of PSICH transmission.

[0156] For example, based on the ConflictDetEnabled and / or ConflictIndEnabled indications in the SCI, the RX WTRU can determine the TX WTRU and / or corresponding information used for PSICH transmission. The RX WTRU can (e.g., determine to) avoid transmission (e.g., not transmit) of PSICH transmission to a TX WTRU with ConflictDetEnabled and / or ConflictIndEnabled indications that are "disabled" in the SCI. For example, the TX WTRU can avoid performing (e.g., not pre-configured for) conflict detection and indication (e.g., due to HW limitations). The TX WTRU can indicate "disabled" in the ConflictDetEnabled indication in the SCI that reserves SL resources. Resources reserved by the TX WTRU may be exempt from conflict detection or indication.

[0157] In some instances, the TX WTRU may instruct ConflictDetEnabled to be "enabled" and ConflictIndEnabled to be "disabled" (e.g., a VRU device performing random resource selection without receiving capability). For example, if (e.g., when) the RX WTRU detects a collision in a resource reserved by the TX WTRU (e.g., a VRU device), the RX WTRU may transmit a PSICH transmission to the colliding TX WTRU. The RX WTRU may instruct (e.g., during a PSICH transmission) the colliding TX WTRU to perform resource reselection, for example, so that the reserved TX WTRU can transmit in the reserved resource without collision.

[0158] For example, based on the resource reservation period in the SCI, the RX WTRU can determine the TX WTRU and / or corresponding information for PSICH transmission. For instance, based on the resource reservation period indicated in the SCI of the conflicting TX WTRU (e.g., P rsvp_TX_2) and / or the resource reservation period indicated in the SCI of the reserved TX WTRU (e.g., P rsvp_TX_1), the RX WTRU can determine which TX WTRU (e.g., from multiple TX WTRUs) to transmit the PSICH to. For instance, if (e.g., when) P rsvp_TX_2 = 0 and P rsvp_TX_1 > 0 and / or if (e.g., when) P rsvp_TX_1 = 0 and P rsvp_TX_2 > 0, the RX WTRU can determine that the detected conflict is a one-time conflict between aperiodic and periodic transmissions. The RX WTRU may (e.g., determine) transmit PSICH to a TX WTRU with (e.g., periodic) resource reservations (e.g., reservations with P rsvp_TX > 0). The RX WTRU may (e.g., determine) instruct the TX WTRU to reselect a resource, for example, so that a collision-free (e.g., non-periodic) transmission can be performed. In some instances, for example, if (e.g., when) prio TX_2 > priority threshold, the RX WTRU may receive configuration information indicating (e.g., pre-configured) priority thresholds and / or may (e.g., determine) transmit PSICH to a TX WTRU with periodic resource reservations (e.g., reservations with P rsvp_TX_2 > 0). For example, if (e.g., when) the L1 priority of a conflicting WTRU’s transmission is higher than (e.g., (pre)configured) threshold (e.g., priority threshold), the RX WTRU may (e.g., therefore) instruct the reserved TX WTRU to reselect a periodic resource to avoid conflict with the non-periodic transmission of the conflicting WTRU.

[0159] For example, if (e.g., when) P rsvp_TX_2 = 0 and P rsvp_TX_1 > 0, the RX WTRU may (e.g., determine, to) transmit a PSICH transmission to indicate a one-time or periodic resource reselection, based on the type of collision detected. For example, if (e.g., when) a one-time collision is detected and prio TX_1 > prio TX_2, the RX WTRU may indicate a one-time resource reselection in a PSICH transmission for the reserved TX WTRU (e.g., as shown in the example in Figure 5A). Resource reselection may (e.g., therefore) be limited to a periodic resource reservation (e.g., one) cycle. For example, if (e.g., when) a periodic collision is detected and prio TX_1 > prio TX_2, the RX WTRU may indicate a periodic resource reselection in a PSICH transmission for the reserved TX WTRU (e.g., as shown in the example in Figure 5B). Resource reselection may be performed for one or more (e.g., all) cycles of resource reservation.

[0160] Figure 4A illustrates an example of a PSICH transfer used for a one-time resource reselection. Figure 5B illustrates an example of a PSICH transfer used for periodic resource selection.

[0161] For example, based on the decoding status of a PSSCH transmission associated with a reserved SCI, the RX WTRU can determine the TX WTRU and / or corresponding information for the PSICH transmission. For example, based on the decoding status of a PSSCH transmission associated with a reserved TX WTRU's SCI, the RX WTRU can determine which TX WTRU to transmit the PSICH to. For example, if (e.g., when) the decoding status is a CRC check (e.g., the PSSCH transmission was correctly decoded), the RX WTRU can transmit the PSICH to the reserved TX WTRU to cancel the retransmission (e.g., as shown in the example in Figure 4C). Cancellation allows conflicting TX WTRUs to perform transmissions without collisions.

[0162] For example, based on the WTRU source and / or destination ID indicated in the SCI for reserving conflicting resources, the RX WTRU can determine the TX WTRU and corresponding information for the PSICH transmission. In an example, for instance, based on the WTRU source and / or destination ID indicated in the SCI for reserving conflicting resources, the RX WTRU can determine which TX WTRU sends the conflict indication transmission (e.g., in a PSICH transmission). In an example, the RX WTRU can determine the TX WTRU transmitting the PSICH transmission to the WTRU source and / or destination ID associated with the V2X service and / or SL application subscribed to by the RX WTRU, as indicated in its SCI. The RX WTRU can instruct the TX WTRU to perform resource reselection during the PSICH transmission.

[0163] For example, based on the power-saving state indicated in the SCI of a reserved resource, the RX WTRU can determine the TX WTRU and / or corresponding information for PSICH transmission. For instance, if (e.g., when) the SL power-saving state indication included in the SCI of a reserved conflicting resource from the TX WTRU indicates a state of reduced power consumption, the WTRU can determine to avoid sending (e.g., not sending) a conflict indication transmission (e.g., in a PSICH transmission) to the TX WTRU. For example, such a TX WTRU in a reduced power consumption state can avoid performing (e.g., not performing) sensing and / or SL reception, and therefore can avoid receiving (e.g., not receiving) and / or acting on the conflict indication transmission. The RX WTRU can transmit the conflict indication to the (e.g., another) TX WTRU that has reserved the conflicting resource and instruct the resource to be reselected.

[0164] For example, based on the resource allocation scheme indicated in the SCI of the reserved resource, the RX WTRU can determine the TX WTRU and corresponding information for PSICH transmission. In an example, if (e.g., when) the TX WTRU applies random resource selection and / or (e.g., partially) sensing resource selection, the RX WTRU can determine to avoid sending (e.g., not sending) collision indication transmissions (e.g., in PSICH transmissions) to the TX WTRU. The resource selection scheme can be indicated in the SCI from the TX WTRU that reserves the conflicting resource. The RX WTRU can transmit the collision indication to the (e.g., other) TX WTRU that reserves the conflicting resource and instruct resource reselection.

[0165] For example, based on the WTRU type indicated in the SCI of a reserved resource, the RX WTRU can determine the TX WTRU and corresponding information for PSICH transmission. In an example, the RX WTRU can determine to avoid sending (e.g., not sending) a collision indication transmission (e.g., in PSICH transmission) to, for example, a TX WTRU, which may be a vulnerable road user (VRU), a low-power wearable device, and / or a WTRU with limited HW capabilities. Such WTRU type indications can be included in the SCI from the TX WTRU of the reserved conflict resource. The RX WTRU can transmit the collision indication to the reserved conflict resource (e.g., another) TX WTRU and instruct resource reselection.

[0166] For example, based on the SL RSRP of the PSCCH of an SCI carrying reserved conflict resources, the RX WTRU can determine the TX WTRU and corresponding information for PSICH transmission. For example, based on the measured RSRP of the PSCCH transmission of an SCI carrying reserved conflict resources, the RX WTRU can determine which TX WTRU sends the conflict indication transmission (e.g., in a PSICH transmission). In one example, the RX WTRU can transmit the PSICH transmission to the TX WTRU with the highest measured RSRP value. In another example, the RX WTRU can transmit the PSICH transmission to the TX WTRU with the highest measured RSRP value that is higher than (e.g., the (pre)configured) RSRP threshold.

[0167] For example, based on the distance between TX WTRUs and RX WTRUs that reserve conflict resources, an RX WTRU can determine the TX WTRU and corresponding information for PSICH transmission. For example, based on the calculated TX-RX distance between each TX WTRU and RX WTRU that reserve conflict resources, an RX WTRU can determine which TX WTRU sends a conflict indication transmission (e.g., in a PSICH transmission). An RX WTRU can calculate the TX-RX distance, for example, based on the area ID indicated in the SCI from the TX WTRU. For example, if (e.g., when) the TX-RX distance is within the MCR indicated in the SCI from the TX WTRU, an RX WTRU can transmit PSICH transmission to a TX WTRU. In an example, an RX WTRU can transmit PSICH transmission to a TX WTRU with the minimum TX-RX distance and whose TX-RX distance is within the MCR indicated in the SCI from the TX WTRU.

[0168] For example, based on the type of conflict detected in a conflicting resource, the RX WTRU can determine the TX WTRU and corresponding information for PSICH transmission. For example, if (e.g., when) the RX WTRU detects a same time slot conflict (e.g., as described herein regarding the determination of RX WTRUs for same time slot conflicts due to overlapping resource reservations), the RX WTRU can determine to send a PSICH or PSFCH transmission to the TX WTRU. A PSICH transmission may include an indication for retransmission of a TB transmitted by the TX WTRU in the conflicting resource.

[0169] For example, if (e.g., when) the RX WTRU detects a conflict due to a previously received resource reservation (e.g., as described herein regarding the determination of an RX WTRU due to a conflict caused by a previously received resource reservation), the RX WTRU may determine to send a conflict indication transmission (e.g., a PSICH transmission). For example, based on the priority of the TB associated with the previously received resource reservation and the priority indicated in the SCI of the reserved resource, the RX WTRU may determine to send a conflict indication transmission (e.g., a PSICH transmission) (e.g., if (e.g., when) the RX WTRU detects a conflict due to a previously accepted resource reservation). The RX WTRU may send a conflict indication transmission to the TX WTRU that has the highest priority indicated in the SCI of the reserved conflicting resource.

[0170] For example, if (e.g., when) the RX WTRU detects a conflict due to its scheduled SL or UL transmission (e.g., as described herein regarding conflict determination of RX WTRUs due to their scheduled SL or UL transmissions), the RX WTRU may determine to send a conflict indication transmission (e.g., a PSICH transmission) to the TX WTRU. For example, if (e.g., when) the priority of the TB used for the SL or UL transmission is higher than the priority indicated in the SCI of the reserved resource, the RX WTRU may determine to send a conflict indication transmission (e.g., a PSICH transmission) to the TX WTRU (e.g., if (e.g., when) the RX WTRU detects a conflict due to its scheduled SL or UL transmission). The RX WTRU may instruct resource reselection in the PSICH transmission. For example, if (e.g., when) the priority of a TB in an SL or UL transmission is lower than the priority indicated in the SCI of the reserved resource, the RX WTRU may determine to avoid sending (e.g., not send) a PSICH transmission and downgrade the SL or UL transmission, and receive the SL TB in the reserved resource (e.g., as indicated in the SCI from the TX WTRU). A higher priority may correspond to a smaller value in the priority bit field of the SCI.

[0171] The RX WTRU can determine the PSICH transmission format and / or resources. The WTRU can receive configuration information indicating (e.g., pre-configured, e.g., from a higher layer) one or more of the following for conflict indication transmission: PSICH transmission format; PSFCH transmission format; and / or PSICH transmission resource configuration.

[0172] The WTRU can receive configuration information indicating (e.g., pre-configured) the PSICH transport format. In some instances, the PSICH transport format may be based on, for example, a Zadoff Chu (ZC) sequence. The WTRU can generate a PSICH transport sequence (e.g., a ZC sequence cyclic offset value) and / or deliver SL collision detection and indication information within a selected PSICH transport sequence. The PSICH transport format may include one or more (e.g., several) bit fields. Each bit field may include (e.g., pre-configured) a set of code points. The WTRU can use the code point values ​​in the PSICH transport bit fields to indicate association information.

[0173] In some instances, for example, if (e.g., when) an SL resource conflict is detected in a resource, the PSICH transmission may indicate information applicable to the resources reserved in the received SCI. A PSICH transmission may indicate one or more of the following: an indication for retransmission of a SL TB transmitted in a PSSCH transmission associated with a received SCI; an indication for cancellation of retransmission of a scheduled SL TB from resources held in a received SCI; an indication for one-time resource reselection (e.g., reselection of a single resource held in a received SCI), for example, for initial transmission of (e.g., new) SL TB associated with a WTRU source and / or destination ID identical to the WTRU source and / or destination ID indicated in the received SCI and / or for retransmission of SL TB transmitted in a PSSCH associated with a received SCI; and / or for a request for periodic reselection (e.g., reselection of periodically held resources in a received SCI), for example, for initial transmission and retransmission of (e.g., new) SL TB associated with a WTRU source and / or destination ID identical to the WTRU source and / or destination ID indicated in the received SCI.

[0174] In some instances, the WTRU may include SL resource conflict and / or indication information (e.g., and HARQ feedback information) in PSFCH transmission format for resources reserved in the received SCI (e.g., if / when HARQ is enabled for SL TB). The PSFCH transmission format may indicate one or more of the following: HARQ ACK for SL TB transmitted in a PSFCH transmission associated with the received SCI; HARQ ACK for SL TB transmitted in a PSFCH transmission associated with the received SCI and / or indication for HARQ retransmission in resources reserved in the received SCI; and / or HARQ ACK for SL TB transmitted in a PSFCH transmission associated with the received SCI and / or indication for HARQ retransmission with resource reselection (e.g., HARQ retransmission in resources different from those reserved in the received SCI due to a detected conflict).

[0175] For example, if (for example, when) the RX WTRU detects a collision in a resource reserved for a new HARQ transmission, the RX WTRU instructs HARQ NACK and resource reselection in a PSFCH transmission.

[0176] The WTRU can receive configuration information indicating (e.g., pre-configured) PSICH resources. These resources may include, for example, PSICH transmission timings, PSICH frequency resources, and / or PSICH sequences. In some instances, a PSICH transmission timing may be an SL slot. Multiple periodic SL slots in the resource pool can be indicated (e.g., pre-configured), for example, as PSICH transmission timings. The WTRU can (e.g., within a PSICH transmission timing) perform PSICH transmissions on one or more indicated (e.g., pre-configured) PSICH symbols, for example, where PSSCH / PSCCH transmissions are not permitted. For example, if (e.g., when) no PSICH transmission timing is indicated (e.g., pre-configured) in the resource pool, collision detection and indication in the resource pool can be disabled.

[0177] In some instances, PSICH transports may be based on (e.g., a single) Entity Resource Block (PRB), for example, for a sequence-based PSICH transport format. Several PRBs may be indicated (e.g., (pre-configured) in a resource pool for PSICH transports. A set of orthogonal sequences (e.g., ZC sequences with different ring offsets) may be indicated (e.g., (pre-configured)). Multiple PSICH transports may be code-domain-multiplexed within (e.g., one) PRB during PSICH transport. PSICH resources may be (e.g., therefore) identified using PRB-based indices and / or the sequences used in the PRB.

[0178] For example, based on one or more of the following, the RX WTRU may determine the resources used for PSICH transmission to the determined TX WTRU in the determined PSICH transmission timing: the WTRU source / destination ID of the determined TX WTRU (e.g., WTRU ID); the index of the SL slot of the SCI in which the reserved resources are received (e.g., index slot); the index of the SL slot of the determined PSICH transmission timing (e.g., index slot); the PSCCH sub-channel reserved by the determined TX WTRU; and / or the PSSCH sub-channel reserved by the determined TX WTRU.

[0179] In some instances, the RX WTRU can determine the index (e.g., WTRU ID + index slot) MOD(N PSICH_resource) corresponding to the reserved resource of PSICH. N PSICH_resource can be the total number of a set of PSICH resources determined within the PRB of the PSSCH sub-channel and / or the PRB of the PSCCH sub-channel in the resource reservation used for collision detection.

[0180] In some instances, frequency resources for PSICH transmission can be based on (e.g., a single) subchannel. The WTRU can determine the subchannel for PSICH transmission, for example, based on mode 2 sensing. The WTRU can perform subchannel-type PSICH transmission on (e.g., (pre)configured) symbols during the PSICH transmission period.

[0181] The RX WTRU can determine PSICH transmission power and parallel PSICH and PSFCH transmissions. The RX WTRU can receive configuration information indicating (e.g., pre-configured) one or more of the following for PSICH transmission power settings for (e.g., single) PSICH transmission and parallel PSICH and / or PSFCH transmissions: PSICH transmission power offset (P0_PSICH); path loss compensation factor (α); downlink path loss (DLPL); SL ​​path loss (SLDL); maximum total number of parallel PSICH and / or PSFCH transmissions (Nmax); SCS digit (u); (e.g., pre-configured) maximum SL power (PSL_MAX); and / or (e.g., pre-configured) maximum SL power (PSL_MAX) if (e.g., when) the measured SL CBR exceeds (e.g., pre-configured) CBR threshold (PSL_MAX_CBR).

[0182] For example, based on the TX WTRU selected for PSICH transmission (e.g., as described herein), the RX WTRU can select which path loss applies to the PSICH transmission power setting. The RX WTRU can set the PSICH transmission power (P PSICH, single) to one of the following: downlink path loss (DLPL) for single PSICH transmission power setting; and / or SL path loss (SLPL) for single PSICH transmission power setting.

[0183] For example, if (e.g., when) a PSICH transmission is sent to a selected TX WTRU and the WTRU source and / or destination ID indicated in the SCI transmitted by this TX WTRU is not associated with a V2X service and / or SL application subscribed to by the RX WTRU, the RX WTRU may determine to use the downlink path loss (DLPL) used for a single PSICH power setting. The RX WTRU may evaluate the DLPL, for example, based on the (e.g., the same) downlink RS used for PUSCH transmission DLPL evaluation. The RX WTRU can be configured with a single PSICH transmission power of either of the following: P PSICH, single = minimum(P SL_MAX, P 0_PSICH + 10log10(2 u) + Alpha*DLPL) dBm; or P PSICH, single = minimum(P SL_MAX_CBR, P 0_PSICH + 10log10(2 u) + Alpha*DLPL) dBm, for example, if (for example, when) the RX WTRU measures a SL CBR higher than (for example, (pre)configured) CBR threshold; or if the RX WTRU is outside the NW coverage area, then the RX WTRU can apply a (pre)configured maximum SL power as follows: P PSICH, single = P SL_maxdBm and P PSICH, single = P SL_max_CBRdBm (for example, if / when the RX WTRU measures a SL CBR higher than (pre)configured CBR threshold).

[0184] For example, if (e.g., when) a PSICH transmission is sent to a selected TX WTRU and the WTRU source and / or destination ID indicated in the SCI transmitted by this TX WTRU is associated with a V2X service and / or SL application subscribed to by the RX WTRU, the RX WTRU can determine to use the SL path loss (SLPL) used for a single PSICH power setting. The RX WTRU can evaluate the DLPL, for example, based on the (e.g., the same) downlink RS used for PUSCH transmission DLPL evaluation. The RX WTRU can set the single PSICH power to one of the following: P PSICH, single = minimum(P SL_MAX, P 0_PSICH+ 10log10(2 u) + Alpha*SLPL) dBm (e.g., where SLPL is the estimated SL path loss based on the SL RS (e.g., SL CSI-RS), PSCCH DMRS and / or PSSCH DMRS transmitted by the TX UE intended for PSICH transmission) or P PSICH, single = minimum(P SL_MAX_CBR, P 0_PSICH+ 10log10(2 u) + Alpha*SLPL) dBm (e.g., if / when the RX WTRU measures an SL CBR higher than the (pre)configured CBR threshold).

[0185] PSICH transmission timing can (e.g., completely) overlap with PSFCH transmission timing. The RX WTRU can perform parallel PSICH and PSFCH transmissions at (e.g., the same) symbol position within the SL time slot. The RX WTRU can receive configuration information indicating (e.g., pre-configured) the (e.g., maximum) total number (N max) of PSICH and PSFCH transmissions with (e.g., one) PSFCH and / or PSICH transmission timing. The RX WTRU can perform prioritization to determine which PSICH and / or PSFCH transmission to perform. The prioritization performed can be associated with one or more of the following: the maximum available power, the determined / scheduled PSICH and / or PSFCH transmissions; or the actual number of PSICH / PSFCH transmissions.

[0186] For example, if (for example, when) the RX WTRU measures a SL CBR higher than (for example, (pre)configured) the critical limit, the RX WTRU can determine that the maximum available power is P max or P max_CBR.

[0187] For example, if (e.g., when) the number of determined and / or scheduled PSICH and / or PSFCH transmissions (e.g., N_schedule) is less than or equal to (e.g., (pre)configured) the maximum number (e.g., N_max) and the total power is less than or equal to the determined maximum available power, the RX WTRU may perform (e.g., all, such as N_schedule) determined and / or scheduled PSICH and / or PSFCH transmissions.

[0188] The RX WTRU can perform decision and / or scheduling (N-schedule) priority of PSICH / PSFCH transmissions, and can determine the actual number (N-actual) of PSICH / PSFCH transmissions based, for example, on whether the number of PSICH and / or PSFCH transmissions (N-schedule) is less than or equal to (e.g., (pre-)configured) maximum number (N-max) and whether the total power is greater than the maximum available power, or whether the number of PSICH and / or PSFCH transmissions (N-schedule) is greater than (e.g., (pre-)configured) maximum number (N-max). For example, based on the SL priority associated with PSICH and / or PSFCH transmissions, the RX WTRU can determine the actual number (N-actual) of PSICH and / or PSFCH transmissions to be performed (e.g., less than the scheduled number) in a descending priority order (e.g., in ascending priority indicator order). Priority can be indicated in the SCI that reserves resources corresponding to PSICH transmissions and the SCI associated with PSSCH transmissions corresponding to PSFCH transmissions. The RX WTRU can determine such actual numbers (N actual) such that the sum of the determined PSICH and / or PSFCH transmission power is less than or equal to the determined maximum available power. The RX WTRU can prioritize the allocation of available power to PSICH / PSFCH transmissions with the highest SL priority and abandon PSICH / PSFCH transmissions with the lowest priority.

[0189] The RX WTRU can determine to execute resource information transmissions to the TX WTRU. In an example, the RX WTRU can determine to transmit (e.g., explicitly) a set of conflicting resources to the TX WTRU. In an example, the RX WTRU can determine such conflicting resources, for example, resources excluded based on the RX WTRU's sensing, resources reserved in previously received SCIs (e.g., as described herein regarding conflict determination of the RX WTRU due to previously received reserved resources), and resources scheduled / reserved by the RX WTRU's own transmissions (e.g., as described herein regarding conflict determination of the RX WTRU due to its scheduled SL or UL transmissions).

[0190] In conflict-related information transmissions, the RX WTRU may include the WTRU source and / or destination IDs associated with the set of conflicting resources. The WTRU source and / or destination IDs may be associated with the V2X service and / or SL application subscribed to by the RX WTRU. In an example, the WTRU source and / or destination IDs may be indicated in a (e.g., explicit) request from the TX WTRU. In an example, the WTRU source and / or destination IDs may be indicated in a resource reservation from the TX WTRU. For example, the RX WTRU may include both the source and destination IDs assigned to a unicast transmission (e.g., via a higher layer, such as a higher-layer message), for example, a unicast transmission between the TX WTRU and the RX WTRU. The RX WTRU may include the destination IDs assigned to multicast and broadcast transmissions (e.g., via a higher layer, such as a higher-layer message), for example, for multicast and broadcast transmissions.

[0191] For example, during a resource selection window, the RX WTRU can determine (e.g., all) conflicting resources. The RX WTRU may indicate such a resource selection window in a (e.g., explicit) request for a resource group from the TX WTRU. In an example, the RX WTRU may receive configuration information indicating (e.g., pre-configured) a resource selection window for determining conflicting resources. The RX WTRU may include resource selection window information, for example, in a resource group transmitted to the TX WTRU. The RX WTRU may include the region ID and / or SL RSRP value measured on the SCI of a previous resource in the (e.g., explicit) request and / or reservation of the resource group from the TX WTRU.

[0192] The behavior of the RX WTRU in SCI decoding can be based on the transmission of resource information to the TX WTRU. The RX WTRU can receive configuration information indicating (e.g., pre-configured) PSCCH resource candidates, which may include several (e.g., consecutive) symbols starting from the second SL symbol in the SL time slot of the SL resource pool and / or several PRBs starting from the lowest PRB of the sub-channel of the SL resource pool.

[0193] The RX WTRU can receive configuration information indicating (e.g., pre-configured) PSCCH decoding resource allocation. Allocation can be, for example, several sub-channels of a resource pool, a resource pool, or a group of resource pools. (e.g., multiple) resource pools can be located (e.g., one) SL BWP or different SL BWPs. SL BWPs can be located in different SL carriers. The RX WTRU can be pre-configured with a group of such PSCCH decoding resource allocations, and (e.g., each of these) resource allocations can be associated with one or more of the following: the WTRU source and / or destination ID associated with the V2X service and / or SL application (e.g., SL URLLC traffic) subscribed to by the RX WTRU; power saving status (e.g., ACTIVE state, ON duration, INACTIVE state, OFF duration); or WTRU capability and / or type (e.g., RedCap WTRU with limited bandwidth).

[0194] The RX WTRU can, for example, determine the PSCCH decoding resource allocation based on the resources provided to the TX WTRU. In an example, the PSCCH can determine which PSCCH resource candidates within the resources provided to the TX WTRU are excluded from the PSCCH decoding resource allocation. For instance, SL slots and sub-channels included in a set of conflicting resources provided to the TX WTRU can avoid being monitored (e.g., not monitored) by the RX WTRU for SCI decoding of transmissions from the TX WTRU.

[0195] In an instance, the RX WTRU can send the TX WTRU a (e.g., explicit) resource group (e.g., a conflict-free resource group) to which it is to be applied. The RX WTRU can prioritize SCI decoding of PSCCH resource candidates in the SL slots and subchannels provided to the TX WTRU.

[0196] The RX WTRU can perform exclusion and / or prioritization of PSCCH resource candidates during the resource selection window indicated in the resource set sent to the TX WTRU (e.g., as described herein). The RX WTRU can provide such resource sets to different TX WTRUs. The RX WTRU can determine which PSCCH resource candidates to exclude and / or prioritize in (e.g., each) SL slot, for example, based on the semi-persistent resource reservations made by each TX WTRU in the SL slot.

[0197] The TX WTRU can determine whether conflict detection and indication are appropriate for resource reservations indicated in the SCI associated with the performed SL transfer. This determination may be based on one or more of the following (e.g., as described herein in relation to SL resource conflict and indication (pre)configuration): a subset of WTRU source and / or destination IDs; SL priority thresholds (e.g., Prio thre); enable / disable indications for WTRU coordination and / or conflict detection (e.g., ConflictDetEnabled); and / or enable / disable indications for WTRU coordination and / or conflict indication (e.g., ConflictIndEnabled).

[0198] The TX WTRU can determine the corresponding PSICH transmission timing for PSICH monitoring of (e.g., each) reserved resources, for example, as described herein (e.g., RX WTRU determination related to the collision detection timing of resources reserved in the received SCI). The TX WTRU and RX WTRU can identify the same PSICH transmission timing for resources in the received SCI. The TX WTRU can determine the corresponding PSICH transmission timing for PSICH monitoring of (e.g., each) reserved resources, for example, based on one or more of the following: collision detection processing time (e.g., T proc ;) and / or collision indication transmission processing time (e.g., T PSICH ).

[0199] The TX WTRU may determine the PSICH resource based on one or more of the following (e.g., as described herein in the RX WTRU determination based on PSICH transmission format and resources): the WTRU source and / or destination ID indicated in the SCI that reserves the resource; the index of the SL time slot of the SCI transmission (e.g., the index time slot); the index of the SL time slot of the determined PSICH transmission timing (e.g., the index time slot); the PSCCH sub-channel reserved by the determined TX WTRU; and / or the PSSCH sub-channel reserved by the determined TX WTRU.

[0200] For example, if (e.g., when) the TX WTRU determines that a resource reservation enable conflict detection and indication is needed for a transmission in the SCI, the TX WTRU can use the determined resource to monitor the PSICH transmission when the PSICH transmission is determined. The TX WTRU can (e.g., if / when the TX WTRU does not receive a PSICH transmission) disable preemption for reserved resources (e.g., if preemption is (pre)configured in the resource pool), and / or can perform initial transmissions and / or retransmissions in reserved resources. Preemption can detect conflicts in reserved resources at the TX WTRU. Conflicts detected by the RX WTRU may not be sufficient for the TX WTRU to skip preemption and reduce processing.

[0201] The TX WTRU may (e.g., if / when the TX WTRU receives a PSICH transmission) enable preemption (e.g., if preemption is (pre)configured in the resource pool, and / or may perform one or more of the following (e.g., based on information indicated in the PSICH for (each) reserved resource): stop retransmission (e.g., if / when the PSICH indicates cancellation of retransmission); perform reselection of a non-periodic reserved resource and / or a (e.g., one) cycle of a periodically reserved resource (e.g., if / when the PSICH indicates a one-time resource conflict and / or reselection); perform reselection of one or more (e.g., all) cycles of a periodically reserved resource (e.g., if / when the PSICH indicates a periodic resource conflict and / or reselection); and / or perform retransmission if / when the PSICH transmission indicates retransmission).

[0202] The TX WTRU can determine conflicting resources, for example, based on multiple received conflicting resource groups. In an example, the TX WTRU can receive transmissions from multiple RX WTRUs, and each transmission may include (e.g., explicitly) resource groups. The TX WTRU can determine which resource groups should be used for SL transmissions, for example, based on information included in the resource groups from the RX WTRUs and / or parameters of the SL transmissions from the TX WTRUs. The information included in the resource groups from the RX WTRUs may include WTRU source and / or destination IDs, resource selection windows, area IDs measured on the TX WTRU, and / or SL RSRPs.

[0203] The parameters for SL transfer of TX WTRU may include the WTRU source and / or destination ID associated with the TB to be transferred, the MCR of the TB to be transferred, and / or the resource selection window.

[0204] In an example, a TX WTRU may determine to apply a resource group when one or more of the following conditions are met: the WTRU source and / or destination ID indicated in the received resource group is the same as the WTRU source and / or destination ID of the SL TB to be transmitted; the TX-RX distance (e.g., calculated based on the area ID indicated in the received resource group and the TX UE's own geographical location) is less than or equal to the MCR of the TB to be transmitted; the SL RSRP indicated in the received resource group is higher than the (e.g., (pre)configured) SL RSRP threshold associated with the MCR of the TB to be transmitted; or the resource selection window indicated in the resource group overlaps with the resource selection window determined to be used for the TB to be transmitted.

[0205] The TX WTRU can thus determine the resource group (e.g., multiple received resource groups) to be applied to the SL TB transmission. In an example, the TX WTRU can determine a combination of resources to include non-overlapping resources that the TX WTRU can select from each determined received resource group. The TX WTRU can select resources from the overlapping segment between the indicated resource selection window and the determined resource selection window of the TB to be transmitted.

[0206] Although the features and elements described above are described in specific combinations, each feature or element may be used alone without other features and elements of the preferred embodiment, or in various combinations with or without other features and elements.

[0207] While the implementation schemes described herein take into account 3GPP-specific protocols, it should be understood that the implementation schemes described herein are not limited to this scenario and can also be applied to other wireless systems. Similarly, while the solutions described herein take into account LTE, LTE-A, New Radio (NR), or 5G-specific protocols, it should be understood that the solutions described herein are not limited to this scenario and can also be applied to other wireless systems.

[0208] The procedures described above can be incorporated into computer-readable media for execution by a computer, software, and / or firmware. Examples of computer-readable media include, but are not limited to, electronic signals (transmitted via wired and / or wireless connections) and / or computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, read-only memory (ROM), random access memory (RAM), temporary registers, cache memory, semiconductor memory devices, magnetic media (such as, but not limited to, internal hard disks and removable disks), magneto-optical media, and / or optical media (such as, CD-ROM discs, and / or digital versatile disks, DVDs)). The processor associated with the software can be used to implement radio frequency transceivers for use in WTRUs, terminals, base stations, RNCs, and / or any host computer.

[0209] 100: Communication System 102, 102a, 102b, 102c, 102d: Wireless Transmit / Receive Unit (WTRU) 104,113:RAN 106,115: Core Network (CN) 108: Public Switched Telephone Network (PSTN) 110: Internet 112: Other networks; networks 114a, 114b: Base stations 115, 116, 117: Empty Intermediate Surfaces 118: Processor 120: Transceiver 122: Transmit / receive element 124: Speaker / Microphone 126: Numeric keypad 128: Monitor / Touchpad 130: Non-removable memory 132: Removable Memory 134: Power Supply 136: Global Positioning System (GPS) Chipset 138: Peripheral Equipment 160a, 160b, 160c: eNode-B 162: Management Entity (MME); AMF 162a, 162b, 162c: eNode-B 164: Service Gateway (SGW) 166: Packet Data Network (PDN) Gateway (or PGW) 180a, 180b, 180c:gNB 182a, 182b: Access and Mobility Management Functions (AMF) 183a, 183b: Dialogue Management Function (SMF) 184a, 184b: User Plane Function (UPF) 185a, 185b: Data Network (DN)

Claims

1. A first wireless transmit / receive unit (WTRU) comprising: a processor configured to: receive configuration information indicating a collision detection processing time, wherein the collision detection processing time is a minimum time for reporting a collision indication; receive first side link control information (SCI) from a second WTRU, wherein the first SCI indicates a first collision indication setting and at least a first resource; receive a second SCI from a third WTRU, wherein the second SCI indicates a second collision indication setting and at least a second resource; determine that the first SCI and the second SCI are received at a time prior to the transmission of a physical side link feedback channel (PSFCH), wherein the time prior to the PSFCH transmission is at least the collision detection processing time prior to the PSFCH transmission; determine that at least the first resource and at least the second resource overlap; and transmit the PSFCH transmission to the second WTRU at least based on a determination that the first collision indication setting is enabled, wherein the PSFCH transmission includes a collision indication.

2. The first WTRU of request item 1, wherein the processor is further configured to: determine a measurement associated with the second SCI; and determine a conflict associated with the first resource and the second resource based on the determination that at least the first resource and at least the second resource overlap and based on a determination that the measurement associated with the second SCI is greater than a first threshold.

3. The first WTRU as requested in Item 2, wherein the measurement system associated with the second SCI is the reference signal received power (RSRP).

4. The first WTRU of request item 1, wherein the processor is further configured to: determine a conflict detection triggering timing based at least on the conflict detection processing time and the first resource, wherein the second SCI is received during the conflict detection triggering timing.

5. The first WTRU as requested in Request 4, wherein the conflict detection processing time is a first conflict detection processing time associated with the third WTRU, and wherein the processor is further configured to: receive an indication of a second conflict detection processing time associated with the second WTRU, wherein the conflict detection triggering timing is further determined based on the second conflict detection processing time associated with the second WTRU.

6. The first WTRU as requested in Request 1, wherein the conflict detection processing time is a duration associated with conflict detection performed by the first WTRU and conflict indication sent by the first WTRU.

7. The first WTRU of request item 1, wherein the determination that at least the first resource and at least the second resource overlap is based on a determination that the first resource and the second resource at least partially overlap.

8. The first WTRU of request item 1, wherein the transmitted PSFCH transmission is further based on the determination that the first SCI and the second SCI were received at the time prior to the PSFCH transmission.

9. As in the first WTRU of request item 1, wherein the transmitted PSFCH transmission is further disabled based on the second collision indication.

10. A method for sidelink collision detection and indication, comprising: receiving configuration information indicating a collision detection processing time, wherein the collision detection processing time is a minimum time for reporting a collision indication; receiving first sidelink control information (SCI) from a first WTRU, wherein the first SCI indicates a first collision indication setting and at least a first resource; receiving a second SCI from a second WTRU, wherein the second SCI indicates a second collision indication setting and at least a second resource; determining that the first SCI and the second SCI were received at a time prior to the transmission of a physical sidelink feedback channel (PSFCH), wherein the time prior to the PSFCH transmission is at least the collision detection processing time prior to the PSFCH transmission; determining that at least the first resource and at least the second resource overlap; and transmitting the PSFCH transmission to the first WTRU at least based on a determination that the first collision indication setting is enabled, wherein the PSFCH transmission includes a collision indication.

11. The method of claim 10, wherein the method further includes: Determine a measurement associated with the second SCI; The determination based on the overlap of at least the first resource and at least the second resource, and the determination based on the measurement associated with the second SCI being greater than a first threshold, determines that a conflict associated with the first resource and the second resource exists.

12. The method of claim 11, wherein the measurement associated with the second SCI is a reference signal received power (RSRP).

13. The method of claim 10, further comprising: determining a conflict detection triggering timing based at least on the conflict detection processing time and the first resource, wherein the second SCI is received during the conflict detection triggering timing.

14. The method of claim 10, wherein the conflict detection processing time is a duration associated with conflict detection performed by a third WTRU and conflict indication sent by the third WTRU.

15. The method of claim 10, wherein the determination that at least the first resource and at least the second resource overlap is based on a determination that the first resource and the second resource at least partially overlap.

16. The method of claim 13, wherein the conflict detection processing time is a first conflict detection processing time associated with the second WTRU, and wherein the method further includes: Receive an indication of a second conflict detection processing time associated with the first WTRU, wherein the timing of the conflict detection trigger is further determined based on the second conflict detection processing time associated with the first WTRU.

17. The method of request item 10, wherein the transmitted PSFCH transmission is further based on the determination that the first SCI and the second SCI were received at the time prior to the PSFCH transmission.

18. The method of request item 10, wherein the transmitted PSFCH transmission is further disabled based on the second collision indication.

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