Side Link Collision Detection and Indication

Abstract

This document describes systems, methods, and means for sidelink (SL) conflict detection and indication (e.g., in New Radio (NR) Vehicle-to-Everything (V2X)). A wireless transmit / receive unit (WTRU) may send resource reservation (e.g., in sidelink control information (SCI)). A receiving (RX) WTRU may receive SCI from (e.g., multiple) transmitting (TX) WTRUs, where these TX WTRUs reserve resources for transmission. These TX WTRUs may not know about other TX WTRUs (e.g., do not know the resources reserved by other TX WTRUs). For example, if the reserved resources overlap (e.g., partially or completely), there may be a conflict in resources. For example, a conflict may occur if multiple TX WTRUs reserve conflicting resources for transmission and / or if these TX WTRUs that reserve conflicting resources for transmission do not reselect non-conflicting resources.

Description

[0001] This divisional application is a divisional application of the application with the filing date of July 27, 2022, application number 202280059570.0, and invention title "Sidelink Collision Detection and Indication".

[0002] Cross - reference to related applications

[0003] This application claims the benefit of U.S. Provisional Application No. 63 / 228,653, filed on August 3, 2021, and U.S. Provisional Application No. 63 / 249,260, filed on September 28, 2021, the entire contents of which are incorporated herein by reference. Background of the Invention

[0004] Mobile communications using wireless communication continue to evolve. The fifth - generation mobile communication radio access technology (RAT) may be referred to as 5G New Radio (NR). The previous - generation (legacy) mobile communication RAT could be, for example, the fourth - generation (4G) Long - Term Evolution (LTE). Summary of the Invention

[0005] Systems, methods, and means for sidelink (SL) collision detection and indication (e.g., in New Radio (NR) vehicle - to - everything (V2X) communications) are described herein. A wireless transmit / receive unit (WTRU) may send resource reservations (e.g., in sidelink control information (SCI)). A receiving (RX) WTRU may receive SCI from (e.g., multiple) transmitting (TX) WTRUs, where these TX WTRUs reserve resources for transmission. These TX WTRUs may not know about other TX WTRUs (e.g., do not know the resources reserved by other TX WTRUs). For example, if the reserved resources overlap (e.g., partially or completely), there may be a conflict in resources. For example, a conflict may occur if multiple TX WTRUs reserve conflicting resources for transmission and / or if these TX WTRUs that reserve conflicting resources for transmission do not reselect non - conflicting resources.

[0006] The RX WTRU (e.g., a first WTRU) may receive configuration information indicating a collision detection processing time (e.g., the time for the RX WTRU to determine that there is a collision and send a collision indication). The RX WTRU may receive a first SCI from a first TX WTRU (e.g., a second WTRU). The first SCI may include an indication (e.g., a first indication) indicating a first resource, a first collision indication setting, and / or a first priority value. The RX WTRU may receive an indication indicating, for example, a collision indication processing time associated with the first TX WTRU. The RX WTRU may determine a collision detection trigger time (e.g., a time window in which the RX WTRU has sufficient time to detect a collision and, for example, send a collision indication to the first TX WTRU) based at least on the collision detection processing time and the first resource. The collision detection trigger time may be determined based on, for example, the collision detection processing time, the collision indication processing time (e.g., associated with the first TX WTRU), and the first resource. For example, during the collision detection trigger time, the RX WTRU may receive a second SCI from a second TX WTRU (e.g., a third WTRU). The second SCI may include an indication (e.g., a second indication) indicating a second resource, a second collision indication setting, and / or a second priority value. The RX WTRU may determine that there is a collision associated with the first resource and the second resource. For example, based on a determination that a measurement result (e.g., reference signal received power (RSRP)) associated with the second SCI is greater than a first threshold, the RX WTRU may determine that there is a collision associated with the first resource and the second resource. For example, based on a determination that the first resource overlaps (e.g., partially or completely) with the second resource, the RX WTRU may determine that there is a collision associated with the first resource and the second resource. The RX WTRU may, for example, send a collision indication to the first TX WTRU. For example, based on a determination that the first collision indication setting is enabled and the second collision indication setting is disabled, the RX WTRU may send a collision indication to the first TX WTRU. For example, based on a determination that the first collision indication setting is enabled, the second collision indication setting is enabled, and the first priority value is greater than the second priority value, the RX WTRU may send a collision indication to the first TX WTRU. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1A is a system diagram showing an exemplary communication system in which one or more of the disclosed embodiments may be implemented.

[0008] Figure 1B is a system diagram showing an exemplary wireless transmit / receive unit (WTRU) that may be used within the Figure 1A shown communication system, according to an embodiment.

[0009] Figure 1Cis a system diagram showing an exemplary radio access network (RAN) and an exemplary core network (CN) that can be used within the Figure 1A shown communication system, according to an embodiment.

[0010] Figure 1D is a system diagram showing another exemplary RAN and another exemplary CN that can be used within the Figure 1A shown communication system, according to an embodiment.

[0011] Figures 2A to 2D Shows an example of a trigger timing for WTRU collision detection for retransmission resource reservation.

[0012] Figure 3 Shows an example of an RX WTRU that performs collision detection and collision indication.

[0013] Figures 4A to 4C Shows an example of a PSICH transmission.

[0014] Figure 5A Shows an example of a PSICH transmission for one-shot resource reselection.

[0015] Figure 5B Shows an example of a PSICH transmission for periodic resource reselection. DETAILED DESCRIPTION

[0016] Systems, methods, and means for sidelink (SL) collision detection and indication (e.g., in New Radio (NR) Vehicle-to-Everything (V2X)) are described herein. A receiver (RX) wireless transmit / receive unit (WTRU) can determine a trigger for collision detection for one or more resources reserved in received SL control information (SCI) associated with a (pre-)configured WTRU source and / or destination identifier (ID), for example, based on information indicated in the received SCI (e.g., L1 priority and time resources) and / or (pre-)configured parameters (e.g., channel busy rate (CBR) and L1 priority threshold). The RX WTRU can detect a collision and / or collision type, for example, based on SCI decoding in a set of SL time slots, which can be determined, for example, based on reserved time resources, reference signal received power (RSRP) threshold configuration, and / or indicated resource reservation period. The RX WTRU can determine a TX WTRU to transmit a physical sidelink indication channel (PSICH) transmission to indicate one-shot resource reselection, periodic resource reselection, cancellation of retransmission, etc., for example, as a result of a detected collision using a corresponding PSICH format and resources. TX WTRU behavior can be determined, for example, based on receiving a PSICH transmission according to PSICH information (e.g., including closing resource preemption).

[0017] Figure 1A FIG. 1 is a schematic diagram illustrating an exemplary communication system 100 in which one or more of the disclosed embodiments may be implemented. The communication system 100 may be a multi-access system that provides content such as voice, data, video, messages, broadcasts, etc. to a plurality of wireless users. The communication system 100 may enable a plurality of 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), etc.

[0018] As Figure 1A shown, the communication system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, a RAN 104 / 113, a CN 106 / 115, a public switched telephone network (PSTN) 108, the Internet 110, and other networks 112, but it should 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, 102d may be any type of device configured to operate and / or communicate in a wireless environment. By way of example, the WTRUs 102a, 102b, 102c, 102d (any one of which may be referred to as a “station” and / or “STA”) may be configured to transmit and / or receive wireless signals and may include user equipment (UE), mobile stations, fixed or mobile subscriber units, subscription-based units, pagers, cellular telephones, personal digital assistants (PDA), smartphones, laptop computers, netbooks, personal computers, wireless sensors, hotspots or Mi-Fi devices, Internet of Things (IoT) devices, watches or other wearable devices, head-mounted displays (HMD), vehicles, drones, medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in an industrial and / or automated processing chain environment), consumer electronic devices, devices operating on commercial and / or industrial wireless networks, etc. Any one of the WTRUs 102a, 102b, 102c, and 102d may be interchangeably referred to as a UE.

[0019] The communication system 100 may further include base station 114a and / or base station 114b. Each of base stations 114a, 114b may be any type of device configured to wirelessly interface with at least one of WTRUs 102a, 102b, 102c, 102d to facilitate access to one or more communication networks such as CN 106 / 115, Internet 110, and / or other networks 112. By way of example, base stations 114a, 114b may be base transceiver stations (BTSs), Node Bs, evolved Node Bs, Home Node Bs, Home evolved Node Bs, gNBs, NR Node Bs, site controllers, access points (APs), wireless routers, etc. Although base stations 114a, 114b are each depicted as a single element, it should be understood that base stations 114a, 114b may include any number of interconnected base stations and / or network elements.

[0020] Base station 114a may be part of RAN 104 / 113, which may further include other base stations and / or network elements (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 wireless 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 of wireless services to a particular geographical area, which may be relatively fixed or may change over time. A cell may further be divided into cell sectors. For example, the cell associated with base station 114a may be divided into three sectors. Thus, in one embodiment, base station 114a may include three transceivers, i.e., one transceiver for each sector of the cell. In an embodiment, base station 114a may employ multiple-input multiple-output (MIMO) technology and may utilize multiple transceivers for each sector of the cell. For example, beamforming may be used to transmit and / or receive signals in a desired spatial direction.

[0021] Base stations 114a, 114b may communicate with one or more of WTRUs 102a, 102b, 102c, 102d via air interface 116, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, centimeter wave, millimeter wave, infrared (IR), ultraviolet (UV), visible light, etc.). Any suitable radio access technology (RAT) may be used to establish air interface 116.

[0022] More specifically, as noted above, the communication system 100 can be a multi-access system and can employ one or more channel access schemes such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, etc. For example, the base stations 114a in the RAN 104 / 113 and the WTRUs 102a, 102b, 102c can implement radio technologies such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which can use Wideband CDMA (WCDMA) to establish the air interfaces 115 / 116 / 117. WCDMA can include communication protocols such as High-Speed Packet Access (HSPA) and / or Evolved HSPA (HSPA+). HSPA can include High-Speed Downlink (DL) Packet Access (HSDPA) and / or High-Speed UL Packet Access (HSUPA).

[0023] In an embodiment, the base stations 114a and the WTRUs 102a, 102b, 102c can implement radio technologies such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which can use Long-Term Evolution (LTE) and / or Advanced LTE (LTE-A) and / or Advanced LTE Pro (LTE-A Pro) to establish the air interface 116.

[0024] In one embodiment, the base stations 114a and the WTRUs 102a, 102b, 102c can implement radio technologies such as NR radio access, which can use New Radio (NR) to establish the air interface 116.

[0025] In an embodiment, the base stations 114a and the WTRUs 102a, 102b, 102c can implement multiple radio access technologies. For example, the base stations 114a and the WTRUs 102a, 102b, 102c can implement LTE radio access and NR radio access together using, for example, the Dual Connectivity (DC) principle. Thus, the air interfaces used by the WTRUs 102a, 102b, 102c can be characterized by multiple types of radio access technologies and / or transmissions to / from multiple types of base stations (e.g., eNBs and gNBs).

[0026] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement radio technologies such as IEEE 802.11 (i.e., Wireless Fidelity (WiFi)), IEEE 802.16 (i.e., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile Communications (GSM), GSM Enhanced Data Rate Evolution (EDGE), GSM EDGE (GERAN), etc.

[0027] Figure 1A The base station 114b in Figure 1A may be, for example, a wireless router, a home Node B, a home evolved Node B, or an access point, and may utilize any suitable RAT to facilitate wireless connectivity in a local area such as a business premise, a home, a vehicle, a campus, an industrial facility, an air corridor (e.g., for drones), a road, etc. In one embodiment, the base station 114b and the WTRUs 102c, 102d may implement radio technologies such as IEEE 802.11 to establish a Wireless Local Area Network (WLAN). In an embodiment, the base station 114b and the WTRUs 102c, 102d may implement radio technologies such as IEEE 802.15 to establish a Wireless Personal Area Network (WPAN). In yet another embodiment, the base station 114b and the WTRUs 102c, 102d may utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.) to establish a pico cell or a femto cell. As Figure 1A shown, the base station 114b may have a direct connection to the Internet 110. Thus, the base station 114b may not need to access the Internet 110 via the CN 106 / 115.

[0028] The RAN 104 / 113 may communicate with the CN 106 / 115, which may be any type of network configured to provide voice, data, applications, and / or Internet Protocol Voice (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. The data may have different Quality of Service (QoS) requirements, such as different throughput requirements, latency requirements, error tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, etc. The CN 106 / 115 may provide call control, billing services, location-based services for mobile, prepaid calling, Internet connectivity, video distribution, etc., and / or perform advanced security functions such as user authentication. Although not shown in Figure 1Ais shown, it should be understood that RAN 104 / 113 and / or CN 106 / 115 may communicate directly or indirectly with other RANs that employ the same RAT as RAN 104 / 113 or different RATs. For example, in addition to being connected to RAN 104 / 113 that may utilize NR radio technology, CN 106 / 115 may also communicate with another RAN (not shown) that employs GSM, UMTS, CDMA2000, WiMAX, E-UTRA, or WiFi radio technology.

[0029] CN 106 / 115 may also act as a gateway for WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the Internet 110, and / or other networks 112. The PSTN 108 may include a circuit-switched telephone network that provides plain old telephone service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices that use common communication protocols such as the Transmission Control Protocol (TCP), the User Datagram Protocol (UDP), and / or the Internet Protocol (IP) in the TCP / IP Internet protocol suite. The network 112 may include wired and / or wireless communication networks owned and / or operated by other service providers. For example, the network 112 may include another CN that is connected to one or more RANs, and the one or more RANs may employ the same RAT as RAN 104 / 113 or a different RAT.

[0030] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communication system 100 may include multi-mode capabilities (e.g., the WTRUs 102a, 102b, 102c, 102d may include multiple transceivers for communicating with different wireless networks over different wireless links). For example, Figure 1A the illustrated WTRU 102c may be configured to communicate with a base station 114a that may employ a cellular-based radio technology and with a base station 114b that may employ IEEE 802 radio technology.

[0031] Figure 1B is a system diagram showing an exemplary WTRU 102. As Figure 1B shown, the WTRU 102 may include a processor 118, a transceiver 120, a transmit / receive element 122, a speaker / microphone 124, a keypad 126, a display / touchpad 128, a non-removable memory 130, a removable memory 132, a power supply 134, a Global Positioning System (GPS) chipset 136, and / or other peripheral devices 138, etc. It should be understood that the WTRU 102 may include any sub-combination of the foregoing elements while remaining consistent with the embodiments.

[0032] The processor 118 can be a general-purpose processor, a dedicated processor, a conventional processor, a digital signal processor (DSP), multiple microprocessors, one or more microprocessors associated with a DSP core, a controller, a microcontroller, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) circuit, any other type of integrated circuit (IC), a state machine, etc. The processor 118 can perform signal encoding, data processing, power control, input / output processing, and / or any other functions that enable the WTRU 102 to operate in a wireless environment. The processor 118 can be coupled to a transceiver 120, which can be coupled to a transmit / receive element 122. Although Figure 1B the processor 118 and the transceiver 120 are depicted as separate components, it should be understood that the processor 118 and the transceiver 120 can be integrated together in an electronic package or chip.

[0033] The transmit / receive element 122 can be configured to transmit signals to or receive signals from a base station (e.g., base station 114a) via an air interface 116. For example, in one embodiment, the transmit / receive element 122 can be an antenna configured to transmit and / or receive RF signals. In an embodiment, the transmit / receive element 122 can be a transmitter / detector configured to transmit and / or receive signals such as IR, UV, or visible light signals. In yet another embodiment, the transmit / receive element 122 can be configured to transmit and / or receive RF and optical signals. It should be understood that the transmit / receive element 122 can be configured to transmit and / or receive any combination of wireless signals.

[0034] Although the transmit / receive element 122 is depicted as a single element in Figure 1B the WTRU 102 can include any number of transmit / receive elements 122. More specifically, the WTRU 102 can employ MIMO technology. Thus, in one embodiment, the WTRU 102 can include two or more transmit / receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals via the air interface 116.

[0035] The transceiver 120 can be configured to modulate the signals to be transmitted by the transmit / receive element 122 and demodulate the signals received by the transmit / receive element 122. As noted above, the WTRU 102 can have multi-mode capabilities. For example, thus, the transceiver 120 can include multiple transceivers to enable the WTRU 102 to communicate via multiple RATs such as NR and IEEE 802.11.

[0036] The processor 118 of the WTRU 102 may be coupled to a speaker / microphone 124, a keypad 126, and / or a display / touchpad 128 (e.g., a liquid crystal display (LCD) display unit or an organic light emitting diode (OLED) display unit) and may receive user input data therefrom. The processor 118 may also output user data to the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128. In addition, the processor 118 may 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. The non-removable memory 130 may include random access memory (RAM), read-only memory (ROM), a hard disk, or any other type of memory storage device. The removable memory 132 may include a subscriber identity module (SIM) card, a memory stick, a secure digital (SD) memory card, etc. In other embodiments, the processor 118 may access information from a memory that is not physically located on the WTRU 102 (such as on a server or a home computer (not shown)) and store data in that memory.

[0037] The processor 118 may receive power from a 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 battery packs (e.g., nickel cadmium (NiCd), nickel zinc (NiZn), nickel metal hydride (NiMH), lithium ion (Li-ion), etc.), a solar cell, a fuel cell, etc.

[0038] The processor 118 may also be coupled to a GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) regarding the current location of the WTRU 102. In addition to or instead of the information from the GPS chipset 136, the WTRU 102 may receive location information from a base station (e.g., base stations 114a, 114b) via an air interface 116 and / or determine its location based on the timing of signals received from two or more nearby base stations. It should be understood that the WTRU 102 may obtain location information by any suitable location determination method while remaining consistent with the embodiments.

[0039] The processor 118 may also be coupled to other peripheral devices 138, which may include one or more software modules and / or hardware modules that provide additional features, functionality, and / or wired or wireless connections. For example, the peripheral devices 138 may include an accelerometer, an electronic compass, a satellite transceiver, a digital camera (for photos and / or videos), a universal serial bus (USB) port, a vibration device, a television transceiver, a hands-free headset, Modules, FM radio units, digital music players, media players, video game player modules, Internet browsers, virtual reality and / or augmented reality (VR / AR) devices, activity trackers, etc. Peripheral device 138 may include one or more sensors, which may be one or more of the following: gyroscopes, accelerometers, Hall effect sensors, magnetometers, orientation sensors, proximity sensors, temperature sensors, time sensors; geographical location sensors; altimeters, light sensors, touch sensors, magnetometers, barometers, gesture sensors, biometric sensors, and / or humidity sensors.

[0040] WTRU 102 may include a full-duplex radio, for which the transmission and reception of some or all signals (e.g., associated with specific subframes for UL (e.g., for transmission) and downlink (e.g., for reception)) may be concurrent and / or simultaneous. The full-duplex radio may include an interference management unit for reducing and / or substantially eliminating self-interference via signal processing performed by hardware (e.g., chokes) or via a processor (e.g., a separate processor (not shown) or via processor 118). In one embodiment, WTRU 102 may include a half-duplex radio, for which the transmission and reception of some or all signals (e.g., associated with specific subframes for UL (e.g., for transmission) or downlink (e.g., for reception)).

[0041] Figure 1C FIG. is a system diagram of RAN 104 and CN 106 according to one embodiment. As noted above, RAN104 may communicate with WTRU 102a, 102b, 102c via air interface 116 using E-UTRA radio technology. RAN 104 may also communicate with CN 106.

[0042] RAN 104 may include evolved Node Bs 160a, 160b, 160c, but it should be understood that RAN 104 may include any number of evolved Node Bs while remaining consistent with the embodiment. Each of evolved Node Bs 160a, 160b, 160c may include one or more transceivers for communicating with WTRU 102a, 102b, 102c via air interface 116. In one embodiment, evolved Node Bs 160a, 160b, 160c may implement MIMO technology. Thus, evolved Node B 160a, for example, may use multiple antennas to transmit wireless signals to and / or receive wireless signals from WTRU 102a.

[0043] Each of evolved Node Bs 160a, 160b, and 160c may be associated with a specific cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in UL and / or DL, etc. As Figure 1C shown, evolved Node Bs 160a, 160b, and 160c may communicate with each other via the X2 interface.

[0044] Figure 1C The CN 106 shown may include a Mobility Management Entity (MME) 162, a Serving Gateway (SGW) 164, and a Packet Data Network (PDN) Gateway (or PGW) 166. Although each of the foregoing elements is depicted as part of the CN 106, it should be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0045] The MME 162 may be connected to each of evolved Node Bs 162a, 162b, and 162c in the RAN 104 via the S1 interface and may act as a control node. For example, the MME 162 may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, bearer activation / deactivation, selecting a specific serving gateway during the initial attachment of the WTRUs 102a, 102b, 102c, etc. The MME 162 may provide control plane functions for handover between the RAN 104 and other RANs (not shown) employing other radio technologies such as GSM and / or WCDMA.

[0046] The SGW 164 may be connected to each of evolved Node Bs 160a, 160b, and 160c in the RAN 104 via the S1 interface. The SGW 164 may generally route and forward user data packets to / from the WTRUs 102a, 102b, 102c. The SGW 164 may perform other functions such as anchoring the user plane during handover between evolved Node Bs, triggering paging when DL data is available for the WTRUs 102a, 102b, 102c, managing and storing the context of the WTRUs 102a, 102b, 102c, etc.

[0047] The SGW 164 may be connected to the PGW 166, which may provide the WTRUs 102a, 102b, 102c with access to a packet switched network such as the Internet 110 to facilitate communication between the WTRUs 102a, 102b, 102c and IP-enabled devices.

[0048] CN 106 can facilitate communication with other networks. For example, CN 106 can provide the WTRUs 102a, 102b, 102c with access to a circuit-switched network (such as the PSTN 108) to facilitate communication between the WTRUs 102a, 102b, 102c and traditional landline communication devices. For example, CN 106 can include an IP gateway (such as an IP Multimedia Subsystem (IMS) server) that serves as an interface between CN 106 and the PSTN 108 or can communicate with the IP gateway. Additionally, CN 106 can provide the WTRUs 102a, 102b, 102c with access to other networks 112, which can include other wired and / or wireless networks owned and / or operated by other service providers.

[0049] Although the WTRU is described in Figures 1A to 1D as a wireless terminal, it is contemplated that in some representative embodiments, such a terminal may (e.g., temporarily or permanently) use a wired communication interface with a communication network.

[0050] In a representative embodiment, the other network 112 can be a WLAN.

[0051] A WLAN in infrastructure basic service set (BSS) mode can have an access point (AP) for the BSS and one or more stations (STAs) associated with the AP. The AP can have access or an interface to a distribution system (DS) or another type of wired / wireless network that carries traffic to and / or from the BSS. Traffic originating from outside the BSS and destined for an STA can reach the STA through the AP and can be delivered to the STA. Traffic originating from an STA and destined for a destination outside the BSS can be sent to the AP to be delivered to the corresponding destination. Traffic between STAs within the BSS can be sent through the AP. For example, the source STA can send traffic to the AP, and the AP can deliver the traffic to the destination STA. Traffic between STAs within the BSS can be considered and / or referred to as peer-to-peer traffic. Peer-to-peer traffic can be sent between a source and a destination STA (e.g., directly between them) using direct link setup (DLS). In some representative embodiments, DLS can use 802.11e DLS or 802.11z tunnel DLS (TDLS). A WLAN using independent BSS (IBSS) mode may not have an AP, and STAs within the IBSS or using the IBSS (e.g., all STAs) can communicate directly with each other. The IBSS communication mode can sometimes be referred to in this document as an "ad-hoc" communication mode.

[0052] When operating in an 802.11ac infrastructure mode or a similar mode of operation, the AP may transmit beacons on a fixed channel, such as the primary channel. The primary channel may be of a fixed width (e.g., 20 MHz bandwidth) or a width dynamically set via signaling. The primary channel may be the operating channel of the BSS and may be used by the STA to establish a connection with the AP. In some representative embodiments, for example, Carrier Sense Multiple Access / Collision Avoidance (CSMA / CA) may be implemented in an 802.11 system. For CSMA / CA, the STA (e.g., each STA) (including the AP) may sense the primary channel. If the primary channel is sensed / detected and / or determined to be busy by a particular STA, the particular STA may back off. Only one STA (e.g., only one station) may transmit in a given BSS at any given time.

[0053] High Throughput (HT) STAs may communicate using a 40 MHz wide channel, e.g., by combining the primary 20 MHz channel with an adjacent or non - adjacent 20 MHz channel to form a 40 MHz wide channel.

[0054] Very High Throughput (VHT) STAs may support 20 MHz, 40 MHz, 80 MHz, and / or 160 MHz wide channels. 40 MHz and / or 80 MHz channels may be formed by combining consecutive 20 MHz channels. A 160 MHz channel may be formed by combining eight consecutive 20 MHz channels, or by combining two non - consecutive 80 MHz channels (which may be referred to as an 80 + 80 configuration). For the 80 + 80 configuration, after channel coding, the data may pass through a segment parser that may divide the data into two streams. Each stream may be separately subjected to Inverse Fast Fourier Transform (IFFT) processing and time - domain processing. These streams may be mapped to two 80 MHz channels and the data may be transmitted by the transmitting STA. At the receiver of the receiving STA, the operations for the 80 + 80 configuration described above may be reversed and the combined data may be sent to the Media Access Control (MAC).

[0055] 802.11af and 802.11ah support operation modes below 1 GHz. Compared to those used in 802.11n and 802.11ac, the channel operation bandwidth and carriers are reduced in 802.11af and 802.11ah. 802.11af supports 5 MHz, 10 MHz, and 20 MHz bandwidths in the TV white space (TVWS) spectrum, and 802.11ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths using non-TVWS spectrum. According to a representative embodiment, 802.11ah may support meter type control / machine type communication, such as MTC devices in a macro coverage area. The MTC devices may have certain capabilities, such as limited capabilities, including supporting (e.g., only supporting) certain bandwidths and / or limited bandwidths. The MTC devices may include a battery with a battery life higher than a threshold (e.g., to maintain a very long battery life).

[0056] A WLAN system that can support multiple channels and channel bandwidths such as 802.11n, 802.11ac, 802.11af, and 802.11ah includes a channel that can be designated as a primary channel. The primary channel may have a bandwidth equal to the maximum common operation bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel may be set and / or restricted by an STA (which supports the minimum bandwidth operation mode) from all STAs operating in the BSS. In an example of 802.11ah, for an STA (e.g., an MTC type device) that supports (e.g., only supports) the 1 MHz mode, the primary channel may be 1 MHz wide, even if the AP and other STAs in the BSS support 2 MHz, 4 MHz, 8 MHz, 16 MHz, and / or other channel bandwidth operation modes. Carrier sensing and / or network allocation vector (NAV) settings may depend on the state of the primary channel. If the primary channel is busy, for example, because an STA (only supporting the 1 MHz operation mode) is transmitting to the AP, the entire available frequency band may be considered busy even if most of the frequency band remains idle and may be available.

[0057] In the United States, the available frequency band for 802.11ah is 902 MHz to 928 MHz. In Korea, the available frequency band is 917.5 MHz to 923.5 MHz. In Japan, the available frequency band is 916.5 MHz to 927.5 MHz. The total available bandwidth for 802.11ah is 6 MHz to 26 MHz, depending on the country code.

[0058] Figure 1D is a system diagram showing RAN 113 and CN 115 according to one embodiment. As pointed out above, RAN113 may employ NR radio technology to communicate with WTRU 102a, 102b, 102c via air interface 116. RAN 113 may also communicate with CN 115.

[0059] RAN 113 may include gNBs 180a, 180b, 180c, but it should be understood that RAN 113 may include any number of gNBs while remaining consistent with the embodiments. Each of gNBs 180a, 180b, 180c may include one or more transceivers to communicate with WTRUs 102a, 102b, 102c via air interface 116. In one embodiment, gNBs 180a, 180b, 180c may implement MIMO technology. For example, gNBs 180a, 108b may utilize beamforming to transmit signals to and / or receive signals from gNBs 180a, 180b, 180c. Thus, gNB 180a, for example, may use multiple antennas to transmit wireless signals to WTRU 102a and / or receive wireless signals from that WTRU. In an embodiment, gNBs 180a, 180b, 180c may implement carrier aggregation technology. For example, gNB 180a may 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 an embodiment, gNBs 180a, 180b, 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).

[0060] WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using transmissions associated with scalable parameter sets. For example, the OFDM symbol interval and / or the OFDM subcarrier interval may vary for different transmissions, different cells, and / or different parts of the radio transmission spectrum. WTRUs 102a, 102b, 102c may use various or scalable-length subframes or transmission time intervals (TTIs) (e.g., containing different numbers of OFDM symbols and / or having an absolute time length that varies continuously) to communicate with gNBs 180a, 180b, 180c.

[0061] gNBs 180a, 180b, 180c can be configured to communicate with WTRUs 102a, 102b, 102c in a stand-alone configuration and / or a non-stand-alone configuration. In the stand-alone configuration, WTRUs 102a, 102b, 102c can communicate with gNBs 180a, 180b, 180c without accessing other RANs (e.g., such as evolved Node Bs 160a, 160b, 160c). In the stand-alone configuration, WTRUs 102a, 102b, 102c can use one or more of gNBs 180a, 180b, 180c as a mobility anchor point. In the stand-alone configuration, WTRUs 102a, 102b, 102c can communicate with gNBs 180a, 180b, 180c using signals in an unlicensed band. In the non-stand-alone configuration, WTRUs 102a, 102b, 102c can communicate with or connect to gNBs 180a, 180b, 180c while also communicating with or connecting to other RANs (such as evolved Node Bs 160a, 160b, 160c). For example, WTRUs 102a, 102b, 102c can implement the DC principle to communicate with one or more gNBs 180a, 180b, 180c and one or more evolved Node Bs 160a, 160b, 160c substantially simultaneously. In the non-stand-alone configuration, evolved Node Bs 160a, 160b, 160c can be used as a mobility anchor for WTRUs 102a, 102b, 102c, and gNBs 180a, 180b, 180c can provide additional coverage and / or throughput for serving WTRUs 102a, 102b, 102c.

[0062] Each of gNBs 180a, 180b, 180c can be associated with a specific cell (not shown) and can be configured to handle radio resource management decisions, handover decisions, scheduling of users in UL and / or DL, support for network slicing, dual connectivity, interworking between NR and E-UTRA, routing of user plane data towards user plane functions (UPFs) 184a, 184b, routing of control plane information towards access and mobility management functions (AMFs) 182a, 182b, etc. As Figure 1D shown, gNBs 180a, 180b, 180c can communicate with each other via the Xn interface.

[0063] Figure 1DThe illustrated CN 115 may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one Session Management Function (SMF) 183a, 183b, and possibly Data Networks (DN) 185a, 185b. Although each of the foregoing elements is depicted as part of CN 115, it should be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0064] The AMF 182a, 182b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via the N2 interface and may serve as a control node. For example, the AMF 182a, 182b may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, support for network slicing (e.g., handling different PDU sessions with different requirements), selection of a particular SMF 183a, 183b, management of the registration area, termination of NAS signaling, mobility management, etc. The AMF 182a, 182b may use network slicing in order to customize CN support for the WTRUs 102a, 102b, 102c based on the type of service used by the WTRUs 102a, 102b, 102c. For example, different network slices may be established for different use cases such as services relying on Ultra-Reliable Low-Latency (URLLC) access, services relying on Enhanced Mobile Broadband (eMBB) access, services for Machine-Type Communication (MTC) access, etc. The AMF 162 may provide control plane functions for handovers between the RAN 113 and other RANs (not shown) employing other radio technologies such as LTE, LTE-A, LTE-A Pro, and / or non-3GPP access technologies such as WiFi.

[0065] The SMF 183a, 183b may be connected to the AMF 182a, 182b in the CN 115 via the N11 interface. The SMF 183a, 183b may also be connected to the UPF 184a, 184b in the CN 115 via the N4 interface. The SMF 183a, 183b may select and control the UPF 184a, 184b and configure the traffic routing through the UPF 184a, 184b. The SMF 183a, 183b may perform other functions such as managing and allocating UE IP addresses, managing PDU sessions, controlling policy enforcement and QoS, providing downlink data notifications, etc. The PDU session type may be IP-based, non-IP-based, Ethernet-based, etc.

[0066] UPF 184a and 184b can be connected via the N3 interface to one or more of gNBs 180a, 180b, 180c in RAN 113, and these gNBs can provide access to a packet switched network (such as the Internet 110) to WTRUs 102a, 102b, 102c to facilitate communication between WTRUs 102a, 102b, 102c and IP-enabled devices. UPF 184a, 184b can perform other functions such as routing and forwarding packets, implementing user plane policies, supporting multi-homed PDU sessions, handling user plane QoS, buffering downlink packets, providing mobility anchoring, etc.

[0067] CN 115 can facilitate communication with other networks. For example, CN 115 can include an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that serves as an interface between CN 115 and the PSTN 108 or can communicate with the IP gateway. Additionally, CN 115 can provide access to other networks 112 to WTRUs 102a, 102b, 102c, and the other networks can include other wired and / or wireless networks owned and / or operated by other service providers. In one embodiment, WTRUs 102a, 102b, 102c can be connected to DNs 185a, 185b via UPF 184a, 184b through the N3 interface to UPF 184a, 184b and the N6 interface between UPF 184a, 184b and local data networks (DNs) 185a, 185b.

[0068] In view of Figures 1A to 1D and Figures 1A to 1D the corresponding descriptions, one or more or all of the functions described herein with reference to one or more of the following can be performed by one or more emulation devices (not shown): WTRUs 102a-d, base stations 114a-b, evolved Node Bs 160a-c, MME 162, SGW 164, PGW 166, gNBs 180a-c, AMFs 182a-b, UPFs 184a-b, SMFs 183a-b, DNs 185a-b and / or any other device described herein. An emulation device can be one or more devices configured to mimic one or more or all of the functions described herein. For example, emulation devices can be used to test other devices and / or simulate network and / or WTRU functions.

[0069] A simulation device can be designed to implement one or more tests of other devices in a laboratory environment and / or an operator network environment. For example, the one or more simulation devices can perform one or more or all functions 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. The one or more simulation devices can perform one or more functions or all functions while being temporarily implemented / deployed as part of a wired and / or wireless communication network. The simulation device can be directly coupled to another device for testing purposes and / or can perform tests using over-the-air wireless communication.

[0070] The one or more simulation devices can perform one or more (including all) functions without being implemented / deployed as part of a wired and / or wireless communication network. For example, the simulation device can be used in a test laboratory and / or a test scenario in a non-deployed (e.g., test) wired and / or wireless communication network to implement tests of one or more components. The one or more simulation devices can be test equipment. Direct RF coupling and / or wireless communication via an RF circuit (e.g., which can include one or more antennas) can be used by the simulation device to transmit and / or receive data.

[0071] Systems, methods, and means for sidelink (SL) conflict detection and indication (e.g., in New Radio (NR) Vehicle-to-Everything (V2X)) are described herein. A wireless transmit / receive unit (WTRU) can send a resource reservation (e.g., in sidelink control information (SCI)). A receiving (RX) WTRU can receive SCI from one or more transmitting (TX) WTRUs, where these TX WTRUs reserve resources for transmission. These TX WTRUs may not know about other TX WTRUs (e.g., do not know the resources reserved by other TX WTRUs). For example, if the reserved resources overlap (e.g., partially or completely), there may be a conflict. For example, a conflict may occur if multiple TX WTRUs reserve conflicting resources for transmission and / or if these TX WTRUs that reserve conflicting resources for transmission do not reselect non-conflicting resources.

[0072] An RX WTRU (e.g., a first WTRU) may receive configuration information indicating a collision detection processing time (e.g., the time for the RX WTRU to determine that there is a collision and send a collision indication). The RX WTRU may receive a first SCI from a first TX WTRU (e.g., a second WTRU). The first SCI may include an indication (e.g., a first indication) indicating a first resource, a first collision indication setting, and / or a first priority value. The RX WTRU may receive an indication indicating, for example, a collision indication processing time associated with the first TX WTRU. The RX WTRU may determine a collision detection trigger timing (e.g., a time window in which the RX WTRU has sufficient time to detect a collision and, for example, send a collision indication to the first TX WTRU) based at least on the collision detection processing time and the first resource. The collision detection trigger timing may be determined based, for example, on the collision detection processing time, the collision indication processing time (e.g., associated with the first TX WTRU), and the first resource. For example, during the collision detection trigger timing, the RX WTRU may receive a second SCI from a second TX WTRU (e.g., a third WTRU). The second SCI may include an indication (e.g., a second indication) indicating a second resource, a second collision indication setting, and / or a second priority value. The RX WTRU may determine that there is a collision associated with the first resource and the second resource. For example, based on a determination that a measurement result (e.g., reference signal received power (RSRP)) associated with the second SCI is greater than a first threshold, the RX WTRU may determine that there is a collision associated with the first resource and the second resource. For example, based on a determination that the first resource overlaps (e.g., partially or completely) with the second resource, the RX WTRU may determine that there is a collision associated with the first resource and the second resource. The RX WTRU may, for example, send a collision indication to the first TX WTRU. For example, based on a determination that the first collision indication setting is enabled and the second collision indication setting is disabled, the RX WTRU may send a collision indication to the first TX WTRU. For example, based on a determination that the first collision indication setting is enabled, the second collision indication setting is enabled, and the first priority value is greater than the second priority value, the RX WTRU may send a collision indication to the first TX WTRU.

[0073] The WTRU may determine the detection of a collision in one or more aperiodic / periodic SL resources reserved by a plurality of mode 2 WTRUs. An indication of the collision may be provided to (e.g., one) WTRU based, for example, on priority, time and frequency allocation, and the reservation interval period indicated in the SCI. The method for SL collision detection and indication may include, for example, one or more of the following.

[0074] For example, the WTRU is configured with one or more of the following: a subset of the WTRU source and / or destination IDs; an SL priority threshold (e.g., Priothre ); SL CBR threshold (e.g., CBR thre ); Conflict detection processing time (e.g., T proc ); Conflict indication transmission processing time (e.g., T PSICH ); Enable / disable indication for conflict detection (e.g., ConflictDetEnabled); Enable / disable indication for conflict indication (e.g., ConflictIndEnabled); SL conflict detection RSRP threshold (e.g., RSRP conflict ); PSICH format; and / or PSICH resource configuration.

[0075] The WTRU may receive resource reservation in the SCI from the first TX WTRU and / or may determine, for example, the conflict detection trigger timing and / or the corresponding source for detection based on one or more of the following: the number of resources reserved in the SCI; the configured conflict detection processing time threshold; the configured conflict indication processing time threshold; the time resource allocation indicated in the received SCI; and / or the resource reservation period indicated in the received SCI. The WTRU may determine the conflict detection trigger timing for SP-based resource reservation including multiple (e.g., two) retransmission resources.

[0076] The WTRU may trigger conflict detection, for example, based on one or more of the following (e.g., determine) under the determined conflict detection trigger conditions: the priority indicated in the received SCI and / or the configured priority threshold (e.g., Prio thre ); the measured SL CBR and / or the configured CBR threshold (e.g., CBR thre ); a ConflictDetEnabled indicated in the received SCI; RSRP; distance; TX WTRU power saving state; resource allocation scheme; TX WTRU type; decoding state; and / or HARQ feedback state.

[0077] The WTRU may detect conflict in one or more resources of the determined conflict detection, for example, based on one or more of the following: the configured RSRP threshold; and / or the RSRP of the SCI transmission from the second TX WTRU of the same resources reserved in the sensing.

[0078] The WTRU may determine, for example, the TX WTRU for conflict indication transmission (e.g., PSICH) and the corresponding (e.g., PSICH) format and information based on one or more of the following: the priorities indicated by the first TX WTRU and the second TX WTRU in the SCI; the resource reservation period indicated by the first TX WTRU and the second TX WTRU in the SCI; the enable / disable indication for conflict indication (e.g., ConflictIndEnabled); and / or the configured PSICH format.

[0079] The WTRU may determine, for example, the resources for the determined PSICH transmission based on one or more of the following: the 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.

[0080] The WTRU may transmit the PSICH to the determined TX WTRU in the determined resources.

[0081] For example, a WTRU such as a receiver (RX) WTRU may determine, for example, the trigger for conflict detection for one or more resources reserved in the received SL control information (SCI) associated with a (pre-)configured WTRU source and / or destination identifier (ID) based on the information indicated in the received SCI (e.g., L1 priority and time resources) and / or (pre-)configured parameters (e.g., channel busy rate (CBR) and L1 priority threshold).

[0082] The RX WTRU may detect conflicts and / or conflict types, for example, based on the SCI decoding in the SL time slot set, which may be determined, for example, based on the reserved time resources, the reference signal received power (RSRP) threshold configuration, and / or the indicated resource reservation period. The types of conflicts may include conflicts specific to beamforming (e.g., FR2) operations, previously received SP-based reservations, SL / UL transmissions, multicast TX / RX conflicts, and / or simultaneous partial overlaps, and the corresponding prioritization and indication transmissions.

[0083] The RX WTRU may determine a TX WTRU to transmit a physical sidelink indication channel (PSICH) transmission to indicate, for example, one-time resource reselection, periodic resource reselection, cancellation of retransmission, etc., as a result of the detected conflict using the corresponding PSICH format and resources.

[0084] The TX WTRU behavior may be determined, for example, based on receiving a PSICH transmission according to the PSICH information (e.g., including disabling resource preemption).

[0085] The WTRU may determine the PSICH power setting. For example, taking into account the DL or SL path loss and concurrent PSICH and PSFCH transmissions, the WTRU may determine the PSICH power setting. The PSICH power setting may be used for PSICH transmission or concurrent PSICH and / or PSFCH transmissions. For example, taking into account prioritization, the WTRU may perform concurrent PSICH and PSFCH transmissions. The prioritization may be based on SL priority (e.g., associated with PSICH and / or PSFCH transmission).

[0086] The WTRU may (e.g., determine) perform conflict information transmission. The conflict information transmission may include information associated with the resource set where there is a conflict. The conflict information transmission may include the WTRU source and / or destination ID associated with the resource set where there is a conflict. The WTRU may perform conflict information transmission to, for example, the TX WTRU. The TX WTRU may determine which resource set to use for transmission based on, for example, the conflict information transmission WTRU source / destination ID, reference signal received power (RSRP), or TX-RX distance. The TX WTRU may combine the resources in the selected set within the resource selection window.

[0087] The behavior of the SCI decoded RX WTRU may be determined based on, for example, resource information transmission to the TX WTRU. For example, the RX WTRU may determine to exclude (e.g., from the decoded resource allocation) candidate resources (e.g., PSCCH candidate resources) within the resources (e.g., in the resource information transmission) provided to the TX WTRU. The RX WTRU may determine to prioritize (e.g., decode) the candidate resources (e.g., PSCCH candidate resources) that are, for example, within the resource sets provided to the TX WTRU (e.g., conflict and non-conflict) in the resource information transmission.

[0088] WTRU-to-WTRU coordination may be enabled and / or provided. Resource allocation (e.g., mode 2 resource allocation) may be improved (e.g., in terms of reliability). The reliability of mode 2 resource selection may be affected by hidden nodes, exposed nodes, half-duplex, and / or uplink (UL) / sidelink (SL) transmission overlaps. The transmitter (TX) WTRU (e.g., mode 2 TX WTRU) may perform resource selection based on sensing, for example, which may not detect problems. Multiple TX WTRUs may transmit concurrently on the same time and frequency resources, which may result in conflicts. There may be persistent conflicts between semi-persistent reserved transmissions, which may reduce the reliability of vehicle-to-everything (V2X) services.

[0089] WTRU - to - WTRU coordination can mitigate one or more problems. Coordination can enable a receiver (RX) WTRU to provide information to assist a TX WTRU in resource selection. Coordination or sharing of information can include, for example (e.g., explicit), a set of resources that may or may not be preferred for a transmission from a TX WTRU. Coordination or sharing of information can include, for example (e.g., implicitly), a conflict indication applicable to resources that may be reserved by a TX WTRU.

[0090] The process of implementing WTRU - to - WTRU coordination can be based on V2X design and / or multiple operational scenarios.

[0091] Excessive signaling overhead and congestion can be caused by conflict indication transmissions. For example, if (e.g., when) an RX WTRU receives an SCI from a TX WTRU in a Physical Side - link Control Channel (PSCCH) in SL time - slot y0, the SL Control Information (SCI) can reserve (e.g., additional) resources in a subsequent SL time - slot, thereby scheduling Physical Side - link Shared Channel (PSSCH) / PSCCH transmissions over the L sub - channels in the same time - slot. Reserved resources can include, for example, multiple (e.g., two) resources for re - transmission of an (e.g., the same) SL Transmission Block (TB) time - slot (e.g., y1 = y0+T1 and y2 = y0+T2). For example, if (e.g., when) the resource reservation period (e.g., P subCH ) is not equal to zero, the resources reserved in one or more SL time - slots (e.g., y0, y1, and y2) can be (e.g., periodically) reserved in SL time - slots (e.g., y0 + n*P rsvp_TX ) for the initial transmission and / or re - transmission of an (e.g., new) TB. There can be several WTRUs in the vicinity that can receive the SCI and perform conflict detection. A WTRU (e.g., each WTRU among several WTRUs) can transmit (e.g., several) indication transmissions. For example, signaling overhead and congestion can be reduced while reliability is increased. rsvp_TX y1 + n*P rsvp_TX y2 + n*P rsvp_TX ) for the initial transmission and / or re - transmission of an (e.g., new) TB. There can be several WTRUs in the vicinity that can receive the SCI and perform conflict detection. A WTRU (e.g., each WTRU among several WTRUs) can transmit (e.g., several) indication transmissions. For example, signaling overhead and congestion can be reduced while reliability is increased.

[0092] The processing capabilities of a WTRU can be improved (e.g., to overcome limitations) to detect, indicate (e.g., one) conflict(s) of the reserved (e.g., all) resources in a SCI and / or operate based on the conflict. 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 an indication transmission to decode, process the indication, and operate based on the indication can utilize more time. The WTRU can participate in V2X mode 2 sensing and resource selection processing to detect and indicate (e.g., each) conflict of the reserved resources (e.g., regardless of the pattern of resources in the time domain). A WTRU that receives an indication can have the ability, limited ability, or no ability to operate based on the indication. For example, a WTRU of the vulnerable road user (VRU) type may not have a receiver and / or may perform random resource selection.

[0093] The WTRU can detect conflicts of resources indicated, for example, in a received SCI. Conflicts of SL resources can be detected. The indication of the conflict can be (pre-)configured. The WTRU can receive configuration information indicating (e.g., pre-configured by a higher layer with) one or more of the following (e.g., related to SL resource conflict detection and indication): a subset of the WTRU source and / or destination identifier(s) (ID); an SL priority threshold (e.g., Prio thre ); an SL channel busy rate (CBR) threshold (e.g., CBR thre ); a conflict detection processing time (e.g., T proc ); a conflict indication transmission processing time (e.g., T PSICH ); an enable / disable indication for WTRU - to - WTRU coordination and / or conflict detection (e.g., ConflictDetEnabled); an enable / disable indication for WTRU - to - WTRU coordination and / or conflict indication (e.g., ConflictIndEnabled); an SL conflict detection reference signal received power (RSRP) threshold (e.g., RSRP conflict ); and / or a PSICH and / or PSFCH resource configuration for WTRU - to - WTRU coordination and / or conflict detection.

[0094] The WTRU may receive configuration information indicating (e.g., preconfigured by a higher layer) a pair of WTRU source and / or destination IDs, e.g., for unicast SL transmission and / or reception. The WTRU may receive configuration information indicating (e.g., preconfigured by a higher layer) the WTRU destination ID, e.g., for multicast and / or unicast SL transmission and reception. The WTRU may receive (e.g., be preconfigured with) configuration information of one or more (e.g., a set of) WTRU source and / or destination IDs, e.g., based on the supported services (e.g., V2X services) and / or applications (e.g., V2X applications). In some examples, a subset of the WTRU source and / or destination IDs may be indicated for (e.g., preconfigured) SL resource conflict and / or indication. The WTRU may, for example, perform SL resource conflict detection and indication on resources reserved for SL transmission associated with the subset of the WTRU source and / or destination IDs.

[0095] In some examples, the WTRU may receive (e.g., be preconfigured with) the SL priority threshold (e.g., Prio thre ) in the SL resource pool. The WTRU may, for example, trigger SL resource conflict detection and indication based on (e.g., preconfigured) Prio thre at the resource conflict detection trigger timing (e.g., within the timing). The SL priority threshold may, for example, enable conflict detection and indication for SL transmissions (e.g., with high priority).

[0096] In some examples, the WTRU may receive indication (e.g., be preconfigured with) the SL CBR threshold (e.g., CBR thre ) in the SL resource pool. The WTRU may, for example, trigger SL resource conflict detection and indication based on (e.g., preconfigured) CBR thre at the resource conflict detection trigger timing (e.g., within the timing). The SL CBR threshold may regulate the increase in SL congestion, which may be caused by indication transmission as a result of SL resource conflict detection.

[0097] The WTRU may receive indication (e.g., be preconfigured with) the WTRU conflict detection processing time threshold (e.g., T proc ). The conflict detection processing time threshold may correspond to the (e.g., minimum) time period required for the WTRU to perform conflict detection (e.g., and transmit the result indication). The time threshold may be represented, for example, by the number of SL time slots. The value of the time threshold may be based on, for example, the WTRU processing capability and / or subcarrier spacing (SCS), e.g., the SCS associated with the SL bandwidth part (BWP) (e.g., preconfigured SL bandwidth part (BWP)).

[0098] A WTRU may receive configuration information that indicates (e.g., is (pre)-configured with) a WTRU conflict detection processing time threshold (e.g., T PSICH ). The conflict indication processing time threshold may correspond to the (e.g., minimum) time period (e.g., required) for the WTRU to receive and decode a conflict indication (e.g., and perform the indicated operations such as resource reselection). The time threshold may be expressed, for example, in terms of the number of SL time slots. The value of the processing time threshold may be based on, for example, the WTRU processing capabilities and / or SCS, e.g., the SCS associated with an SL BWP (e.g., a (pre)-configured SL BWP).

[0099] In some examples, the RX WTRU may determine, for example, based on T proc and / or T PSICH the conflict detection trigger timing (e.g., the most recent conflict detection trigger timing) of the resources reserved in the SCI received from the TX WTRU. The RX WTRU may trigger conflict detection for the reserved SL time slots, e.g., to capture as many conflicting SL resource reservations as possible. The conflicting SL resource reservations may be reservations of sub-channels that are partially or fully overlapping in an SL time slot (e.g., the same SL time slot). The trigger for conflict detection may occur, for example, (e.g., early enough) to allow for the processing time for conflict detection and indication transmission at the RX WTRU as well as the indication reception and indication operation at the TX WTRU.

[0100] In some examples, the WTRU may receive an enable / disable indication (e.g., ConflictDetEnabled) for conflict detection (e.g., is (pre)-configured with). The TX WTRU may include an indication of ConflictDetEnabled in the SCI for PSSCH / PSCCH transmission. For example, if (e.g., when) the indication for conflict detection is set to "enabled", the RX WTRU may perform conflict detection on the resources reserved in the SCI. For example, if (e.g., when) the indication for conflict detection is set to "disabled", the RX WTRU may suppress (e.g., not perform) conflict detection on the resources reserved in the SCI.

[0101] In some examples, a WTRU may receive (e.g., be (pre)-configured with) an enable / disable indication for conflict indication (e.g., ConflictIndEnabled). The TX WTRU may include an indication of ConflictIndEnabled in, for example, the SCI of a PSSCH / PSCCH transmission. For example, if (e.g., when) the indication for conflict indication is set to "enabled", the RX WTRU may transmit a conflict indication to the TX WTRU for (e.g., specific to) the resources reserved in the SCI. For example, if (e.g., when) the indication for conflict indication is set to "disabled", the RX WTRU may refrain from performing (e.g., not perform) the transmission of a conflict indication to the TX WTRU for the resources reserved in the SCI.

[0102] The ConflictDetEnabled and ConflictIndEnabled SCI indications may support WTRUs with limited or no reception capabilities (e.g., VRU devices without RX hardware (HW)). A WTRU (e.g., with limited or no reception capabilities) may perform random resource selection without sensing. The resulting SL transmissions may be subject to increased conflicts. SL resource detection of randomly selected resources may improve transmission reliability. For example, due to HW limitations, the performance of (e.g., not performing) indication transmission may be inhibited.

[0103] In some examples, a WTRU may receive an indication (e.g., be (pre)-configured with) of an SL conflict detection RSRP threshold (e.g., RSRP conflict ) configuration information. The WTRU may, for example, determine that a conflict has been detected in the reserved resources 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, for example, on the priority indicated in the SCI for resources reserved (e.g., the same) by different WTRUs.

[0104] In an example, the WTRU may receive configuration information indicating (e.g., preconfigured with) PSICH and / or PSFCH resources for WTRU - to - WTRU coordination and / or collision detection. The resource configuration information may be associated with (e.g., dedicated to) the SL resource pool. If PSCIH and / or PSFCH are configured in the resource pool, the WTRU may determine that, for example, WTRU - to - WTRU coordination and / or collision detection and indication may be enabled, and the WTRU may perform WTRU - to - WTRU coordination and / or collision detection for SL transmission (e.g., using the resources of the resource pool).

[0105] The RX WTRU may determine the collision detection opportunity for the resources reserved in the received SCI. In some examples, the RX WTRU may determine the Physical Side - Link Indication Channel (PSICH) transmission opportunity based on, for example, the PSICH resource configuration of the resource pool, which may be located (e.g., each) before the reserved SL time slot of the reserved resources by (e.g., at least) T PSICH . The (e.g., preconfigured) periodicity of the PSICH transmission opportunity may be, for example, one per SL time slot, one per two SL time slots, one per four SL time slots, etc. The WTRU may determine the time offset between the determined PSICH transmission opportunity and the reserved SL time slot (e.g., T offset ). For example, if (e.g., when) the PSICH transmission period is one per SL time slot, then T offset may be set to be equal to T PSICH . For example, if (e.g., when) the PSICH transmission periodicity is one per two SL time slots (e.g., according to the index of the reserved SL time slot), then T offset may be set to be equal to T PSICH or T PSICH +1 (e.g., as shown in the example of Figures 2A to 2D ).

[0106] The RX WTRU may determine the (e.g., nearest) collision detection trigger opportunity corresponding to the reserved resources, which may be located before the determined PSICH transmission opportunity by (e.g., at least) T proc . The RX WTRU may (e.g., thus) determine that the collision detection trigger opportunity for the reserved resources may occur before the resources for collision detection by (e.g., at least) (T proc +T offset ).

[0107] Figures 2A to 2D Illustrates an example of the WTRU collision detection trigger opportunity for retransmission resource reservation.

[0108] The RX WTRU may determine a conflict detection opportunity for resources reserved for retransmission in the received SCI. The RX WTRU may determine one or more (e.g., the most recent) conflict detection opportunities for resources reserved for retransmission in the SCI received in the SL time slot y0, based on, for example, one or more of the following: conflict detection processing time (e.g., T proc ); conflict indication transmission processing time (e.g., T PSICH ); one or more PSICH transmission opportunities in the resource pool (e.g., (pre)-configured); the number of resources reserved in the received SCI; for resources reserved in the SL time slot (e.g., y1 = y0 + T1), the time resource allocation indicated in the received SCI (e.g., T1); and / or for resources reserved in the SL time slot (e.g., y2 = y0 + T2), the time resource allocation indicated in the received SCI (e.g., T2).

[0109] The RX WTRU may determine one or more (e.g., the most recent) conflict detection opportunities for resources reserved for retransmission in the SCI received in the SL time slot y0, as described, for example, in one or more of the following examples. The (e.g., most recent) conflict detection opportunity may represent a time instance after which the WTRU may suppress triggering (e.g., not trigger) conflict detection. The WTRU may (e.g., determine) trigger inter-WTRU coordination and / or conflict detection in the conflict detection opportunity (e.g., SL time slot (SL time slot n)) (e.g., before the determined (e.g., most recent) conflict detection opportunity). The triggering may be based on (e.g., (pre)-configured) conditions (e.g., as discussed herein).

[0110] In some examples, (e.g., one) retransmission resource may be reserved in the SL time slot y1 = y0 + T1. As shown in the example of Figure 2A , T1 >= T proc + T offset . The RX WTRU may determine the most recent conflict detection opportunity in the SL time slot y trig = y0 + T1 - T proc - T offset , which corresponds to the reserved retransmission resource in the SL time slot y1 (e.g., if T1 >= T proc + T offset ). For example, if T1 < T proc + T offset , the RX WTRU may (e.g., determine) suppress performing (e.g., not perform) conflict detection on the reserved resources.

[0111] In some examples, multiple (e.g., two) retransmission resources may be reserved in the SL time slots y1 = y0 + T1 and y2 = y0 + T2. As inFigure 2B As shown in the example in, T1 >= T proc +T offset_1 , and T2 - T1 >= T proc +T offset_2 . The RX WTRU may determine multiple (e.g., the most recent two) collision detection opportunities. The RX WTRU may determine that the collision detection opportunity will be, for example, in SL time slot y trig_1 = y0 + T1 - T proc -T offset_1 corresponding to the resources reserved in SL time slot y1. The RX WTRU may determine that the collision detection opportunity will be, for example, in SL time slot y trig_2 = y0 + T1 - T proc -T offset_2 corresponding to the resources reserved in SL time slot y2.

[0112] In some examples, multiple (e.g., two) retransmission resources may be reserved in SL time slots y1 = y0 + T1 and y2 = y0 + T2. As Figure 2C shown in the example in, T1 < T proc +T offset , and T2 - T1 >= T proc +T offset . The RX WTRU may determine the most recent collision detection opportunity in SL time slot y trig = y0 + T2 - T proc -T offset_2 corresponding to the reserved retransmission resource in SL time slot y2. The RX WTRU may suppress performing (e.g., not performing) collision detection on the reserved retransmission resource in SL time slot y1.

[0113] In some examples, multiple (e.g., two) retransmission resources may be reserved in SL time slots y1 = y0 + T1 and y2 = y0 + T2. As Figure 2D shown in the example in, T1 >= T proc +T offset , and T2 - T1 < T proc +T offset . The RX WTRU may determine the (e.g., most recent) collision detection opportunity in SL time slot y trig = y0 + T1 - T proc -T offset_1 corresponding to the reserved retransmission resources in SL time slots y1 and y2. The RX WTRU may perform collision detection on the reserved retransmission resources in SL time slot y1 and SL time slot y2.

[0114] In some examples, multiple (e.g., two) retransmission resources may be reserved in SL time slots y1 = y0 + T1 and y2 = y0 + T2. For example, if T1 < T proc +T offset and T2 - T1 < T proc +T offset , then the RX WTRU may (e.g., determine) suppress the execution (e.g., not perform) of collision detection on the reserved resources.

[0115] The RX WTRU may determine the collision detection timing for resources reserved for initial transmission and / or retransmission in the received SCI. For example, if (e.g., when) the value of the resource reservation period indicated in the SCI (e.g., P rsvp_TX ) is greater than zero, the RX WTRU may receive the periodic resource reservation in the SCI in SL time slot y0. The (e.g., same) subchannels reserved in SL time slots y0, y1, and y2 (e.g., if retransmission resources are reserved) may be reserved (e.g., periodically) in SL time slots y0 + n*P rsvp_TX , y1 + n*P rsvp_TX and y2 + n*P rsvp_TX . The value of n may be from 1 to N. N may be, for example, the indicated (e.g., preconfigured by a higher layer) resource reselection value.

[0116] The RX WTRU may determine one or more (e.g., the nearest) collision detection timings for resources reserved for (e.g., initial) transmission and / or retransmission in the SCI received in SL time slot y0, for example, based on one or more of the following: the collision detection processing time (e.g., T proc ); the collision indication transmission processing time (e.g., T PSICH ); one or more PSICH transmission timings preconfigured in the resource pool; the number of resources reserved in the received SCI; for the resources reserved in SL time slot y1 = y0 + T1, the time gap indicated in the received SCI (e.g., T1); for the resources reserved in SL time slot y2 = y0 + T2, the time gap indicated in the received SCI (e.g., T2); and / or the resource reservation period P rsvp_TX .

[0117] The RX WTRU may determine one or more (e.g., the nearest) collision detection timings for resources reserved for retransmission in the SCI received in SL time slot y0 (e.g., for a reservation period, such as each reservation period). One or more of the following may be applied.

[0118] An initial resource may be reserved (e.g., periodically) in SL time slot y0 + n*P rsvp_TX , where Prsvp_TX >= T proc + T offset 。For example, if an initial resource is reserved (e.g., periodically) in SL time slot y0 + n*P rsvp_TX and P rsvp_TX >= T proc + T offset then the RX WTRU may determine the (e.g., nearest) conflict detection occasion in SL time slot y trig_n = y0 + n*P rsvp_TX - T proc - T offset which corresponds to the reserved initial transmission of the (e.g., new) SL TB in SL time slot y0 + n*P rsvp_TX of the (e.g., new) SL TB in SL time slot y0 + n*P

[0119] An (e.g., one) initial resource may be reserved (e.g., periodically) in SL time slot y0 + n*P rsvp_TX e.g., where P rsvp_TX < T proc + T offset For example, if an initial resource is reserved (e.g., periodically) in SL time slot y0 + n*P rsvp_TX and P rsvp_TX < T proc + T offset then the RX WTRU may (e.g., determine) refrain from performing (e.g., not perform) conflict detection on the reserved resource

[0120] (e.g., one) initial transmission and (e.g., one) retransmission resource (y1 = y0 + T1) may be reserved in SL time slots y0 = y0 + n*P rsvp_TX and y1 = y1 + n*P rsvp_TX e.g., where P rsvp_TX >= T proc + T offset_1 and T1 >= T proc + T offset_2 For example, if (e.g., one) initial transmission and (e.g., one) retransmission resource (y1 = y0 + T1) are reserved (e.g., periodically) in SL time slots y0 = y0 + n*P rsvp_TX and y1 = y1 + n*P rsvp_TX and P rsvp_TX >= T proc + T offset_1 while T1 >= T proc + T offset_2Among them, the RX WTRU can determine multiple (e.g., the last two) collision detection opportunities. The RX WTRU can determine multiple (e.g., two) of the most recent collision detection opportunities, where one of the most recent collision detection opportunities includes SL time slot y trig_n_1 = y0 + n*P rsvp_TX -T proc -T offset_1 The collision detection opportunity in corresponds to the resources reserved in SL time slot y0 + n*P rsvp_TX Among them, the RX WTRU can determine multiple (e.g., two) of the most recent collision detection opportunities, where one of the most recent collision detection opportunities includes SL time slot y trig_n_2 = y0 + n*P rsvp_TX + T1 - T proc -T offset_2 The collision detection opportunity in corresponds to the resources reserved in SL time slot y1 + n*P rsvp_TX Among them.

[0121] (e.g., one) initial transmission and (e.g., one) retransmission resource (y1 = y0 + T1) can be reserved in SL time slot y0 = y0 + n*P rsvp_TX and y1 = y1 + n*P rsvp_TX Among them, for example, where P rsvp_TX <T proc +T offset_1 and T1 >= T proc +T offset_2 . For example, if (e.g., one) initial transmission and (e.g., one) retransmission resource (y1 = y0 + T1) are reserved (e.g., periodically) in SL time slot y0 = y0 + n*P rsvp_TX and y1 = y1 + n*P rsvp_TX and P rsvp_TX <T proc +T offset_1 while T1 >= T proc +T offset_2 Among them, the RX WTRU can determine SL time slot y trig = y0 + n*P rsvp_TX + T1 - T proc -T offset_2 The (e.g., most recent) collision detection opportunity in corresponds to the reserved retransmission resources in SL time slot y1 + n*P rsvp_TX Among them. The RX WTRU can suppress the execution (e.g., not execute) of the collision detection of the reserved retransmission resources in SL time slot y0 + n*P rsvp_TX Among them.

[0122] (For example, one) initial transmission and (for example, one) retransmission resource (y1 = y0 + T1) may be reserved in the SL time slot y0 = y0 + n*P rsvp_TX and y1 = y1 + n*P rsvp_TX where, for example, P rsvp_TX >= T proc + T offset_1 and T1 < T proc + T offset_2 For example, if (for example, one) initial transmission and (for example, one) retransmission resource (y1 = y0 + T1) are reserved (for example, periodically) in the SL time slot y0 = y0 + n*P rsvp_TX and y1 = y1 + n*P rsvp_TX and P rsvp_TX >= T proc + T offset_1 while T1 < T proc + T offset_2 the RX WTRU may determine the most recent conflict detection opportunity in the SL time slot y trig = y0 + n*P rsvp_TX - T proc - T offset_1 corresponding to the reserved retransmission resources in the SL time slots y0 + n*P rsvp_TX and y1 + n*P rsvp_TX The RX WTRU may perform conflict detection on the reserved retransmission resources in the two SL time slots (for example, at a conflict detection opportunity).

[0123] (For example, one) initial transmission and (for example, one) retransmission resource (y1 = y0 + T1) may be reserved in the SL time slot y0 = y0 + n*P rsvp_TX and y1 = y1 + n*P rsvp_TX where, for example, P rsvp_TX < T proc + T offset_1 and T1 < T proc + T offset_2 For example, if (for example, one) initial transmission and (for example, one) retransmission resource (y1 = y0 + T1) are reserved (for example, periodically) in the SL time slot y0 = y0 + n*P rsvp_TX and y1 = y1 + n*P rsvp_TX and P rsvp_TX < T proc + T offset_1 and T1 < T proc + T offset_2 the RX WTRU may (for example, determine) refrain from performing (for example, not perform) conflict detection on (for example, any) reserved resources.

[0124] For example, if / when determining the (e.g., most recent) conflict detection trigger instance for such semi-persistent resource reservation (e.g., if an (e.g., initial) transmission and an (e.g., retransmission) resource (y1 = y0 + T1) are reserved (e.g., periodically) in an SL time slot y0 = y0 + n*P rsvp_TX ), the RX WTRU may suppress consideration (e.g., not consider) of the time gap (T1) between the initial transmission and the retransmission. For example, if P rsvp_TX >= T proc + T offset , the RX WTRU may determine the (e.g., most recent) conflict detection instance in the SL time slot y trig_n = y0 + n*P rsvp_TX - T proc - T offset , which may correspond to the (e.g., two) resources reserved for the initial transmission of the (e.g., new) SL TB in the SL time slot y0 + n*P rsvp_TX and its retransmission in the SL time slot y1 = y1 + n*P rsvp_TX .

[0125] If an (e.g., initial) transmission and multiple (e.g., two) retransmission resources (y1 = y0 + T1 and y2 = y0 + T2) are reserved (e.g., periodically) in the SL time slots y0 = y0 + n*P rsvp_TX , y1 = y1 + n*P rsvp_TX and y2 = y2 + n*P rsvp_TX , 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 RXWTRU may determine multiple (e.g., three) most recent conflict detection instances. In the example, the RX WTRU may determine the (e.g., one of the multiple) most recent conflict detection instance in the SL time slot y trig_n_1 = y0 + n*P rsvp_TX - T proc - T offset_1 , which may correspond to the resources reserved in the SL time slot y0 + n*P rsvp_TX . The RX WTRU may determine the (e.g., one of the multiple) most recent conflict detection instance in the SL time slot y trig_n_2 = y0 + n*P rsvp_TX + T1 - T proc - T offset_2 , which may correspond to the resources reserved in the SL time slot y1 + n*P rsvp_TXThe resources reserved in. The RX WTRU may determine the SL time slot y trig_n_3 = y0 + n*P rsvp_TX + T2 - T proc - T offset_3 The (e.g., one of multiple) most recent collision detection opportunities in, corresponding to the resources reserved in the SL time slot y1 + n*P rsvp_TX in.

[0126] If (e.g., one) initial transmission and two retransmission resources (y1 = y0 + T1 and y2 = y0 + T2) are reserved (e.g., periodically) in the SL time slot y0 = y0 + n*P rsvp_TX , y1 = y1 + n*P rsvp_TX and y2 = y2 + n*P rsvp_TX in, and if P rsvp_TX < T proc + T offset_1 and T1 < T proc + T offset_2 and T2 < T proc + T offset_3 , then the RX WTRU may determine to suppress (e.g., not perform) the collision detection on the (e.g., any) reserved resources.

[0127] For example, if (e.g., when) determining the most recent collision detection triggering opportunity for (e.g., such) (e.g., semi-persistent) resource reservation (e.g., if (e.g., one) initial transmission and two retransmission resources (y1 = y0 + T1 and y2 = y0 + T2) are reserved (e.g., periodically) in the SL time slot y0 = y0 + n*P rsvp_TX , y1 = y1 + n*P rsvp_TX and y2 = y2 + n*P rsvp_TX in), then the RX WTRU may suppress considering (e.g., not consider) the time gaps (e.g., T1, T2) between the initial transmission and the retransmissions. If P rsvp_TX >= T proc + T offset (e.g., and as described herein, reserving the initial transmission and two retransmission resources), then the RX WTRU may determine the SL time slot y trig_n = y0 + n*P rsvp_TX - T proc – T offset The most recent collision detection opportunity in, which may correspond to the initial transmission of the (e.g., new) SL TB in the SL time slot y0 + n*P rsvp_TX and the multiple (e.g., three) resources reserved for its retransmissions in the SL time slot y1 = y1 + n*P rsvp_TX and the SL time slot y2 = y2 + n*P rsvp_TX in.

[0128] The RX WTRU may (e.g., determine) to trigger conflict detection at a (e.g., determined) conflict detection trigger occasion. The RX WTRU may (e.g., determine) to trigger conflict detection in an SL time slot (e.g., time slot n) before a (e.g., determined) (e.g., most recent) conflict detection trigger occasion (e.g., corresponding to the resources reserved in the SCI received in SL time slot y0). The determination to trigger conflict detection may be based on, for example, one or more of the following: a subset of the WTRU source and / or destination IDs; an SL priority threshold (e.g., Prio thre ); an SL CBR threshold (e.g., CBR thre ); an enable / disable indication for WTRU - to - WTRU coordination and / or conflict detection (e.g., ConflictDetEnabled); PSICH / PSFCH resource configuration information; the SL RSRP of the PSCCH carrying the SCI in SL time slot y_0; the distance between the RX WTRU and the TX WTRU using the area ID and the minimum communication requirement (MCR) (e.g., specific to the SL TB to be transmitted in the reserved resources) indicated in the SCI received in SL time slot y0; an SL power saving state indication (e.g., indicated in the SCI received in SL time slot y0); a resource allocation scheme (e.g., indicated in the SCI received in SL time slot y0); a WTRU type indication (e.g., indicated in the SCI received in SL time slot y0); the decoding state and / or HARQ feedback state of the PSSCH transmission in the resources reserved in the SCI received in SL time slot y0; and / or a (e.g., explicit) request from the TX WTRU for WTRU - to - WTRU coordination and / or conflict detection.

[0129] In some examples, the RX WTRU may receive configuration information indicating (e.g., pre - configured by a higher layer) a subset of the WTRU source / destination IDs, for example, for SL resource conflict and indication. The RX WTRU may receive a resource reservation in the SCI of the PSSCH / PSCCH transmission. For example, if the WTRU source and / or destination ID indicated in the received SCI is within the indicated (e.g., pre - configured) subset, the RX WTRU may (e.g., determine) to trigger conflict detection.

[0130] In some examples, the RX WTRU may receive an indication (e.g., pre - configured with) an SL priority threshold (e.g., Prio thre) configuration information. The RX WTRU can receive resource reservation in the SCI of the PSSCH / PSCCH transmission. 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) trigger conflict detection.

[0131] The WTRU can receive configuration information indicating (e.g., being (pre-)configured with) the SL CBR threshold in the SL resource pool (e.g., CBR thre ) configuration information. The RX WTRU can receive resource reservation in the SCI of the PSSCH / PSCCH transmission. For example, if (e.g., when) the CBR measured at the resource conflict detection trigger timing is lower than the (pre-)configured SL CBR threshold, the RX WTRU can (e.g., determine) trigger conflict detection.

[0132] In some examples, the WTRU can receive configuration information indicating (e.g., being (pre-)configured with) an enable / disable indication (e.g., ConflictDetEnabled) for conflict detection. The RX WTRU can receive resource reservation in the SCI of the PSSCH / PSCCH transmission. For example, if (e.g., when) the indication of ConflictDetEnabled in the received SCI is set to "enabled", the RX WTRU can (e.g., determine) trigger conflict detection.

[0133] The RX WTRU can receive configuration information of a resource pool (e.g., including PSICH / PSFCH resources) (e.g., being (pre-)configured with). The presence of PSICH / PSFCH resources in the (pre-)configured resource pool can indicate WTRU - to - WTRU coordination and / or enable conflict detection for the transmission using the resources of the resource pool. For example, if (e.g., when) the reserved resources are included in the resource pool (e.g., having a PSICH / PSFCH resource configuration), the RX WTRU can determine to trigger conflict detection for the reserved resources.

[0134] For example, if (e.g., when) the measured SL RSRP of the PSCCH of the SCI carrying the reserved resources in the SL time slot y_0 exceeds the (pre-)configured SL RSRP threshold, the RX WTRU can determine to trigger conflict detection for the reserved resources. In an example, the WTRU can receive configuration information indicating (e.g., being (pre-)configured with) a set of SL RSRP thresholds, and (e.g., each) SL RSRP threshold in the set of SL RSRP thresholds can be associated with an SL priority. The RX WTRU can determine the SL RSRP threshold corresponding to the L1 priority value indicated in the SCI of the resources reserved for conflict detection.

[0135] In an example, for instance, if (e.g., when) the TX-RX distance does not exceed the MCR indicated in the SCI of the reserved resources for collision detection, the RX WTRU may determine to trigger collision detection of the reserved resources. 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 by the RX WTRU. The RX WTRU may determine the geographical location of the TX WTRU indicated by the area ID of the received TX WTRU (e.g., as the center of a geographical area), and may calculate the TX-RX distance, for example, based on the geographical locations of the TX WTRU and the RX WTRU.

[0136] For example, if (e.g., when) the SL power saving state indication (e.g., included in the SCI of the reserved resources) indicates a state of reduced power consumption, the RX WTRU may (e.g., determine) suppress triggering (e.g., not trigger) collision detection of the reserved resources. For example, the TX WTRU may be in a power saving state where sensing and / or reception are restricted 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 the resource reservation included in the SCI, and the RX WTRU may (e.g., determine) suppress triggering (e.g., not trigger) collision detection of such SL transmissions.

[0137] In an example, for instance, if (e.g., when) a random and / or partial resource selection scheme is indicated in the SCI of the reserved resources, the RX WTRU may (e.g., determine) suppress triggering (e.g., not trigger) collision detection of the reserved resources. In an example, the TX WTRU may (e.g., randomly) select resources for SL transmission, for example, without performing sensing. This may be due to power saving and / or HW limitations, such as a TX-only WTRU without RX HW. In an example, the TX WTRU may perform partial sensing for SL transmission, and the RX WTRU may (e.g., be (pre)-configured to) suppress triggering (e.g., not trigger) collision detection of such transmissions.

[0138] In an example, for instance, if (e.g., when) a (e.g., (pre)-configured) WTRU type is indicated in the SCI of the reserved resources, the RX WTRU may (e.g., determine) suppress (e.g., not trigger) collision detection of the reserved resources. Such a (e.g., (pre)-configured) WTRU type may include vulnerable road users (VRUs), low-power wearable devices, and / or WTRUs with limited HW capabilities. The RX WTRU may (e.g., be (pre)-configured to) suppress triggering (e.g., not trigger) collision detection of SL transmissions performed by such types of WTRUs.

[0139] The RX WTRU may, for example, trigger conflict detection for the reserved resources (e.g., determine) based on the decoding status and / or HARQ feedback status of the PSSCH transmission received in the resources reserved in the SCI received in the SL time slot y0 (e.g., if / when HARQ is enabled). The RX WTRU may receive configuration information indicating (e.g., being (pre)-configured with) the thresholds for decoding CRC errors and / or HARQ NACK. For example, if (e.g., when) the decoding CRC error and / or HARQ NACK corresponding to the PSSCH transmission received in the resources reserved in the SCI received in the SL time slot y0 exceeds the (pre)-configured threshold, the RX WTRU may (e.g., determine) trigger conflict detection. In an example, the RX WTRU may perform the conflict detection in the SL time slot y0 + n*P rsvp_TX 、y1 + n*P rsvp_TX and y2 + n*P rsvp_TX by receiving the PSSCH transmission in the (e.g., semi-persistent) reserved resources, where, for example, n may be from 1 to N, and N may be a resource reselection value (e.g., indicated by a higher layer and / or (pre)-configured).

[0140] In an example, for example, if (e.g., when) the RX WTRU receives an (e.g., explicit) request from the TX WTRU, the RX WTRU may (e.g., determine) trigger inter-WTRU coordination and / or conflict detection. The (e.g., explicit) request may include the WTRU source and / or destination ID associated with the V2X service and / or SL application (e.g., subscribed by the RX WTRU). The RX WTRU may (e.g., determine) trigger inter-WTRU coordination and / or conflict detection for the received resource reservation (e.g., based on the received request), such as including the WTRU source and / or destination ID indicated in the (e.g., explicit) request.

[0141] Figure 3 An example of an RX WTRU performing conflict detection and conflict indication is shown.

[0142] The RX WTRU may detect a conflict based on a trigger (e.g., at the time of the trigger) (e.g., determining that a condition is met). For example, due to the detected overlapping resource reservations (e.g., as Figure 3As shown, the RX WTRU may determine a conflict. The RX WTRU may determine that conflict detection in SL time slot n has been triggered (e.g., a condition has been met). The RX WTRU may process the decoded SCI and / or RSRP measurements in the determined set of subchannels and / or SL time slots (e.g., based on the triggering of conflict detection in SL time slot n) to determine, for example, whether a conflict is detected in the reserved resources for conflict detection. SL conflict detection may include, for example, one or more of the following (e.g., performed by the RX WTRU): determining one or more conflict detection parameters; performing SCI decoding; determining the overlap of reserved resources; determining conflict detection based on the overlapping reservation; and / or determining the type of detected conflict.

[0143] The RX WTRU may determine one or more conflict detection parameters. One or more (e.g., conflict detection) parameters, such as one or more of the following parameters, may be indicated in the received (e.g., (pre)-configured by a higher layer) configuration information: the SL conflict detection RSRP threshold (e.g., RSRP conflict ); the conflict detection window (e.g., T window , such as 1000 SL time slots); the demodulation reference signal (DM-RS) for measurement (e.g., PSCCH DM-RS or PSCCH DM-RS); and / or the 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., conflict detection) parameters, such as one or more of the following parameters, may be indicated in the SCI of the resources reserved in an SL time slot (e.g., SL time slot y) for conflict detection (e.g., from a reserved TX WTRU): the L1 priority (e.g., prio TX_1 ) indicated, for example, in the received SCI and / or associated with the WTRU source and / or destination ID (pre)-configured for the RX WTRU (e.g., as a result of the V2X services and / or applications supported by the RX WTRU); the number of reserved subchannels (e.g., L subCH ); and / or the resource reservation period (e.g., P rsvp_TX_1 ).

[0144] The RX WTRU may perform SCI decoding in (e.g., every) SL time slot within the conflict detection window (e.g., from SL time slot (n - T window ) to SL time slot (n)) in (e.g., all) subchannels of the resource pool.

[0145] The RX WTRU may determine the overlap of reserved resources, e.g., if (e.g., when) the SCI decoded in an SL time slot includes an L subCHReservation of partially or fully overlapping sub-channels. The SL time slot can be, for example, any SL time slot in the range from SL time slot (y - 32) to SL time slot (y). The SL time slot can include an SCI transmission of resources reserved for retransmission, and the resources can overlap with the resources reserved in SL time slot (y). The SL time slot can be, for example, an (e.g., any) SL time slot that is q * P' rsvp_TX time slots before SL time slot (y). In some examples, P' rsvp_TX can be an (e.g., any) (pre-)configured resource reservation period, and / or q can be a non-zero positive integer. The SL time slot can include an SCI transmission of reserved periodic resources, and the periodic resources can overlap with the resources reserved in SL time slot (y).

[0146] The RX WTRU can determine conflict detection, for example, based on the overlapping reservation decoded in the SCI and / or the RSRP measured by the (e.g., (pre-)configured) DM-RS (e.g., PSCCH or PSSCH DM-RS) associated with the decoded SCI. 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 ), then the RX WTRU can determine that a conflict has been detected. The RSRP can be calculated, for example, based on the L1 priorities (e.g., prio TX_1 and prio TX_2 ) indicated in multiple (e.g., two) SCIs of the reserved overlapping resources. conflict

[0147] The RX WTRU can determine the type of detected conflict (e.g., one-time conflict or periodic conflict) based on, for example, one or more of the following: the resource reservation period (e.g., P rsvp_TX_1 ), which can be indicated in the SCI (e.g., indicated by the reserved TX WTRU); and / or the resource reservation period (e.g., P rsvp_TX_2 ), which can be indicated in the SCI (e.g., including the overlapping resource reservation), for example, indicated by the conflicting TX WTRU.

[0148] In some examples, P rsvp_TX_2 = 0, and / or P rsvp_TX_1 = 0. The RX WTRU can determine that the detected conflict can be the result of a non-periodic transmission (e.g., and can occur once), where the detected conflict can be a one-time conflict (e.g., if P rsvp_TX_2 = 0 and / or P rsvp_TX_1 = 0). In some examples, P rsvp_TX_1 and P rsvp_TX_2 > 0 while 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). 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 , the RX WTRU may determine that the detected collision can be the result of periodic transmissions (e.g., and can occur periodically), where the detected collision can be a periodic collision. A periodic collision can result in a persistent collision between periodic transmissions.

[0149] For example, if (e.g., when) there are multiple resources (e.g., as shown in the example of Figure 2D ), the RX WTRU may perform collision detection on the (e.g., each) reserved resource that can be included in triggering collision detection (e.g., as described herein).

[0150] For example, due to overlapping resource reservations, the RX WTRU may determine a same - time - slot collision. In the example, the RX WTRU may perform collision detection on the resources reserved in the same time slot (e.g., SL time slot y0), in which the SCI of the reserved resource can be received. The collision detection can be based on the parameters indicated in the (e.g., each) decoded resource reservation received in the SL time slot y0. These parameters may include the WTRU source and / or destination ID, and / or the number of reserved sub - channels (L subCH ).

[0151] For example, if (e.g., when) the following two occur, the RX WTRU may determine that a collision is detected in the SL time slot y0: the SCI decoded from multiple (e.g., two or more) PSCCHs in the SL time slot y0 indicates overlapping reservations on (e.g., at least) (e.g., one) sub - channel reserved for PSSCH transmission in the same SL time slot; and the WTRU source and / or destination ID indicated in the overlapping resource reservation is associated with the V2X service and / or SL application subscribed by the RX WTRU.

[0152] In the example, for example, if (e.g., when) the following two occur, the RX WTRU may determine that a collision is detected in the SL time slot y0: the SCI decoded from multiple (e.g., two or more) PSCCHs in the SL time slot y0 indicates the same WTRU source and / or destination ID specific to multicast transmission; and the WTRU source and / or destination ID indicated in the reservation is associated with the V2X service and / or SL application subscribed by the RX WTRU.

[0153] The RX WTRU may determine a conflict due to a previously received resource reservation. In an example, the WTRU may determine conflict detection based on a previously received semi-persistent resource reservation and a resource reservation that triggers conflict detection (e.g., based on the trigger for conflict detection in SL slot n). The WTRU may perform one or more of the following in association with burst detection.

[0154] The RX WTRU may determine conflict detection parameters, such as one or more of the following conflict detection parameters: parameters indicated in the SCI for resource reservation in an SL slot (e.g., SL slot y) for conflict detection (e.g., from a reserved TX WTRU); and / or parameters indicated in the SCI previously received from another TX WTRU in a semi-persistent resource reservation.

[0155] The parameters indicated in the SCI for resource reservation in an SL slot (e.g., SL slot y) for conflict detection (e.g., from a reserved TX WTRU) may include the number of reserved sub-channels (L subCH_1 ), the resource reservation period (P rsvp_TX_1 ), and / or the TCI state (TCI1) of the transmission in the reserved resources.

[0156] The RX WTRU may determine conflict detection parameters, such as parameters indicated in the SCI previously received from another TX WTRU in a semi-persistent resource reservation. The WTRU source and / or destination ID indicated in such an SCI may be among the IDs to be received by the RX WTRU (e.g., (pre)-configured). The parameters indicated in the SCI received (e.g., previously from another TX WTRU in a semi-persistent resource reservation) may include the number of reserved sub-channels (L subCH_2 ), the reserved SL slot, the resource reservation period (e.g., P rsvp_TX_2 ), and P rsvp_TX_2 >0, and / or the TCI state (TCI2) of the transmission in the reserved resources.

[0157] For example, if (e.g., when) there is a previously received resource reservation in a time slot (y) (e.g., the SL slot reserved by another TXWTRU may overlap with time slot (y)) and one or more of the following conditions exist, the RX WTRU may determine that a conflict is detected: the reserved sub-channels overlap (e.g., partially or completely) with the L in time slot (y); or the receive spatial domain filters associated with TCI1 and TCI2 are spatially orthogonal (e.g., the RX WTRU cannot receive both of them using one RX beam). subCH Or the receive spatial domain filters associated with TCI1 and TCI2 are spatially orthogonal (e.g., the RX WTRU cannot receive both of them using one RX beam).

[0158] The RX WTRU may, for example, determine the type of detected conflict (e.g., one-time or periodic conflict) based on a first resource reservation period (e.g., P rsvp_TX_1 ) indicated by the reserved TX WTRU in the SCI and / or a second resource reservation period (e.g., P rsvp_TX_2 ) indicated by the conflicting TX WTRU in the SCI including overlapping resource reservations. 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), then the RX WTRU may determine that the detected conflict is the result of periodic transmissions and may occur periodically, and the detected conflict may be a periodic conflict. A periodic conflict may result in a persistent conflict between periodic transmissions.

[0159] In an example, for instance, if (e.g., when) m is below a (pre-)configured threshold, the RX WTRU may determine that the detected conflict is a periodic conflict. For example, if (e.g., when) m equals one, the reserved resources may overlap in each reservation period. For example, if (e.g., when) m equals two, the reserved resources may overlap every two reservation periods.

[0160] The RX WTRU may determine a conflict, for example, based on (e.g., due to) its scheduled SL or UL transmission. In an example, if (e.g., when) one of the following transmissions made by the RX WTRU was previously reserved in time slot (y) and the WTRU source and / or destination ID indicated in the SCI of the reserved resources in time slot (y) is associated with the V2X service and / or SL application subscribed by the RX WTRU, then the RX WTRU may determine that a conflict has been detected: an SL transmission scheduled by the network (e.g., gNB) in time slot (y) based on SL mode 1 resource allocation, an SL transmission reserved by the RX WTRU in time slot (y) based on SL mode 2 resource allocation, and / or a UL transmission scheduled by the network (e.g., gNB) in time slot (y). The RX WTRU may suppress (e.g., not be able to) receive in the time slot of its transmission (e.g., due to the half-duplex limitation of SL operation).

[0161] The WTRU may transmit a resource conflict indication (e.g., in a PSICH transmission, for example, as Figure 3 shown). The RX WTRU may determine the TX WTRU and / or corresponding information for the PSICH transmission. For example, if (e.g., when) conflict detection is triggered for a conflict detection trigger occasion and a conflict is detected (e.g., as Figure 3As shown, the RX WTRU can determine the TX WTRU to transmit the PSICH transmission. The conflict detection trigger timing may include a time window in which the RX WTRU has sufficient time to detect a conflict and, for example, send a conflict indication to the TX WTRU. The resources where a conflict is detected at the corresponding conflict detection trigger timing may be referred to as resources with a conflict. (For example, of the TX WTRU to which the PSICH transmission is to be sent) The determination may be based on, for example, one or more of the following: one or more L1 priorities indicated in the SCI of the reserved overlapping resources (e.g., prio TX_1 and prio TX_2 ); an enable / disable indication for WTRU - to - WTRU coordination and / or conflict detection (e.g., ConflictDetEnabled); an enable / disable indication for WTRU - to - WTRU coordination and / or conflict indication (e.g., ConflictIndEnabled); an SL CBR threshold (e.g., CBR thre ); the decoding result of the PSSCH transmission associated with the SCI of the reserved resources; the type of detected conflict (e.g., one - time or periodic); the WTRU source and / or destination ID indicated in the SCI of the reserved resources with a conflict; the SL power saving indication indicated in the SCI of the reserved resources with a conflict; the WTRU type indication indicated in the SCI of the reserved resources with a conflict; the resource allocation scheme indicated in the SCI of the reserved resources with a conflict; the SL RSRP of the PSCCH transmission carrying the SCI of the reserved resources with a conflict; and / or the distance between the RX WTRU and the TX WTRU of the reserved resources with a conflict.

[0162] The RX WTRU can, for example, determine the TX WTRU for the PSICH transmission and / or corresponding information based on the L1 priority indication in the SCI (e.g., carried in the PSCCH transmission, e.g., as Figure 3 shown). The RX WTRU can, for example, determine which TX WTRU to transmit the PSICH transmission to based on the L1 priority indicated in the received SCI of the reserved resources (e.g., prio TX_1 ) and / or based on the L1 priority indicated in the decoded SCI including the overlapping resource reservation (e.g., prio TX_2 ). The RX WTRU can (e.g., determine) transmit the PSICH transmission to the TX WTRU with a lower priority (e.g., lower L1 priority) (e.g., as Figure 3 shown). The RX WTRU can transmit to the TX WTRU (e.g., the conflict TX WTRU, as Figure 4Btransmit a PSICH transmission (e.g., triggered based on the RX WTRU detecting the presence of a conflict), where the conflicting TX WTRU is requesting to reserve resources that overlap with resources that have already been reserved (e.g., the resources reserved by the reserved TX WTRU as shown in the example of Figure 4B as shown in the example of). For example, if (e.g., when) prio TX_1 <prio TX_2 (e.g., Figure 4B prio indicating a higher priority in TX_1 , e.g., a lower value of prio may indicate a higher priority), then the RX WTRU may transmit a PSICH transmission to the conflicting TX WTRU. The RX WTRU may transmit a PSICH transmission (e.g., triggered based on the RX WTRU detecting the presence of a conflict) to the TX WTRU that transmitted the resource reservation for which the RX WTRU is monitoring for conflicts (e.g., the reserved TX WTRU as shown in the example of Figure 4A as shown in the example of). For example, if (e.g., when) prio TX_1 >prio TX_2 (e.g., Figure 4A prio indicating a lower priority in TX_1 , e.g., a higher value of prio may indicate a lower priority), then the RX WTRU may transmit a PSICH transmission to the reserved TX WTRU. The RX WTRU may detect the trigger of the presence of a conflict when receiving a resource reservation from the conflicting TX WTRU. The RX WTRU may detect the trigger of the presence of a conflict at an offset time from the time of receiving the resource reservation from the conflicting TX WTRU (e.g., as shown in Figure 4A and Figure 4B ), e.g., obtained from the conflict detection processing time associated with the RX WTRU. The PSICH transmission may include an indication to reselect different resources. For example, if (e.g., when) the CBR measured at the resource conflict detection trigger instance is higher than (e.g., (pre-)configured) the SL CBR threshold, then the RX WTRU may determine to suppress the transmission (e.g., not transmit) the PSICH transmission (e.g., with equal L1 priority). For example, the RX WTRU may randomly select the TX WTRU to perform the PSICH transmission (e.g., with equal L1 priority). For example, if (e.g., when) the conflict detection includes multiple (e.g., two) reserved resources and / or a conflict is detected in each of the multiple resources, then the RX WTRU may transmit simultaneous PSICH transmissions to the reserved and conflicting TX WTRUs at the same PSICH transmission instance. The RX WTRU may perform TX power sharing between the simultaneous PSICH transmissions.

[0163] Figures 4A to 4CAn example of a PSICH transmission is shown.

[0164] The RX WTRU may determine, for example, the TX WTRU and / or corresponding information for PSICH transmission based on the ConflictDetEnabled and / or ConflictIndEnabled indications in the SCI. The RX WTRU may (e.g., determine) suppress transmitting (e.g., not transmit) a PSICH transmission to the TX WTRU that has an indication of ConflictDetEnabled and / or ConflictIndEnabled set to "disabled" in the SCI. For example, the TX WTRU may suppress performing (e.g., not being (pre)-configured for) conflict detection and indication (e.g., due to HW limitations). The TX WTRU may indicate "disabled" ConflictDetEnabled in the SCI for reserving SL resources. The resources reserved by the TX WTRU may not be subject to conflict detection or indication.

[0165] In some examples, the TX WTRU may indicate "enabled" ConflictDetEnabled and "disabled" ConflictIndEnabled (e.g., a VRU device performing random resource selection without reception capabilities). For example, if (e.g., when) the RX WTRU detects a conflict in the resources reserved by the TX WTRU (e.g., a VRU device), the RX WTRU may transmit a PSICH transmission to the conflicting TX WTRU. The RX WTRU may indicate (e.g., in the PSICH transmission) to the conflicting TX WTRU to perform resource reselection, such that the reserved TX WTRU may continue to transmit in the reserved resources without conflict.

[0166] The RX WTRU may determine, for example, the TX WTRU and / or corresponding information for PSICH transmission based on the resource reservation period in the SCI. The RX WTRU may, for example, determine which TX WTRU (e.g., among multiple TX WTRUs) to transmit the PSICH transmission to based on the resource reservation period indicated in the SCI of the conflicting TX WTRU (e.g., P rsvp_TX_2 ) and / or the reserved TX WTRU (e.g., P rsvp_TX_1 ). For example, 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 may determine that the detected conflict is a one-time conflict between an aperiodic transmission and a periodic transmission. The RX WTRU may (e.g., determine) transmit to the TX WTRU with (e.g., periodic) resource reservation (e.g., with Prsvp_TX TX WTRU transmits a PSICH transmission with a reservation > 0. The RX WTRU may (e.g., determine) indicate a reselection resource for the TX WTRU such that (e.g., an aperiodic) transmission can be performed without conflict. In some examples, e.g., if (e.g., when) prio TX_2 > a priority threshold, the RX WTRU may receive configuration information indicating (e.g., preconfigured with) the priority threshold and / or may (e.g., determine) transmit a PSICH transmission to a reserved TX WTRU with a periodic resource reservation (e.g., where P rsvp_TX_2 > 0). For example, if (e.g., when) the L1 priority of the transmission of a conflicting WTRU is higher than a (e.g., preconfigured) threshold (e.g., the priority threshold), the RX WTRU may (e.g., thus) indicate to the reserved TX WTRU to reselect a periodic resource to avoid a conflict with the aperiodic transmission of the conflicting WTRU.

[0167] For example, if (e.g., when) P rsvp_TX_2 = 0 and P rsvp_TX_1 > 0, the RX WTRU may (e.g., determine) transmit a PSICH transmission to indicate a one-time or periodic resource reselection, e.g., based on the type of conflict detected. For example, if (e.g., when) a one-time conflict is detected and prio TX_1 > prio TX_2 , the RX WTRU may indicate a one-time resource reselection to the reserved TX WTRU in the PSICH transmission (e.g., as shown in the example of Figure 5A ). The resource reselection may (e.g., thus) be limited to (e.g., one) period of the periodic resource reservation. For example, if (e.g., when) a periodic conflict is detected and prio TX_1 > prio TX_2 , the RX WTRU may indicate a periodic resource reselection to the reserved TX WTRU in the PSCIH transmission (e.g., as shown in the example of Figure 5B ). The resource reselection may be performed for one or more (e.g., all) periods of the resource reservation.

[0168] Figure 4A Shows an example of a PSICH transmission for one-time resource reselection. Figure 5B Shows an example of a PSICH transmission for periodic resource reselection.

[0169] The RX WTRU may determine, for example, the TX WTRU and / or corresponding information for PSICH transmission based on the decoding status of the PSSCH transmission associated with the SCI of the reserved resources. The RX WTRU may determine, for example, which TX WTRU to transmit the PSICH transmission to based on the decoding status of the PSSCH transmission associated with the SCI from the reserved TX WTRU. For example, if (e.g., when) the decoding status is a CRC check (e.g., the PSSCH transmission is correctly decoded), the RX WTRU may transmit a PSICH transmission to the reserved TX WTRU to cancel the retransmission (e.g., as shown in the example of Figure 4C ). Canceling allows for the transmission of the conflicting TX WTRUs to be performed without conflicts.

[0170] The RX WTRU may determine, for example, the TX WTRU and corresponding information for PSICH transmission based on the WTRU source and / or destination ID indicated in the SCI of the reserved conflicting resources. In an example, the RX WTRU may determine, for example, which TX WTRU to send a conflict indication transmission (e.g., in the PSICH transmission) based on the WTRU source and / or destination ID indicated in the SCI of the reserved conflicting resources. In an example, the RX WTRU may determine to transmit a PSICH transmission to a TX WTRU whose SCI indicates a WTRU source and / or destination ID associated with the V2X service and / or SL application subscribed to by the RX WTRU. The RX WTRU may indicate in the PSICH transmission that the TX WTRU performs resource reselection.

[0171] The RX WTRU may determine, for example, the TX WTRU and corresponding information for PSICH transmission based on the power saving status indicated in the SCI of the reserved resources. For example, if (e.g., when) the SL power saving status included in the SCI of the reserved conflicting resources from the TX WTRU indicates a state for indicating reduced power consumption, the WTRU may determine to suppress sending (e.g., not sending) a conflict indication transmission (e.g., in the PSICH transmission) to the TX WTRU. For example, a TX WTRU in such a reduced power consumption state may suppress performing (e.g., not performing) sensing and / or SL reception, and thus may suppress receiving (e.g., not be able to receive) and / or operating according to the conflict indication transmission. The RX WTRU may transmit a conflict indication to the (e.g., other) TX WTRUs of the reserved conflicting resources and indicate resource reselection.

[0172] The RX WTRU may determine the TX WTRU and corresponding information for PSICH transmission, for example, based on the resource allocation scheme indicated in the SCI of the reserved resources. In an example, for instance, if (e.g., when) the TX WTRU applies random source selection and / or (e.g., partially) sensing-based resource selection, the RX WTRU may determine to suppress sending (e.g., not send) a conflict indication transmission (e.g., in the PSICH transmission) to the TX WTRU. The resource selection scheme may be indicated in the SCI from the TX WTRU of the resources where a reservation conflict exists. The RX WTRU may transmit a conflict indication to the (e.g., other) TX WTRU of the resources where a reservation conflict exists, and indicate resource reselection.

[0173] The RX WTRU may determine the TX WTRU and corresponding information for PSICH transmission, for example, based on the WTRU type indicated in the SCI of the reserved resources. In an example, the RX WTRU may determine to suppress sending (e.g., not send) a conflict indication transmission (e.g., in the PSICH transmission) to the TX WTRU that may be a vulnerable road user (VRU), a low-power wearable device, and / or a WTRU with limited HW capabilities. Such WTRU type indication may be included in the SCI from the TX WTRU of the resources where a reservation conflict exists. The RX WTRU may transmit a conflict indication to the (e.g., other) TX WTRU of the resources where a reservation conflict exists, and indicate resource reselection.

[0174] The RX WTRU may determine the TX WTRU and corresponding information for PSICH transmission, for example, based on the SL RSRP of the PSCCH carrying the SCI of the resources where a reservation conflict exists. The RX WTRI may determine which TX WTRU sends a conflict indication transmission (e.g., in the PSICH transmission), for example, based on the measured RSRP of the PSCCH transmission carrying the SCI of the resources where a reservation conflict exists. In an example, the RX WTRU may transmit a PSICH transmission to the TX WTRU with the highest measured RSRP value. In an example, the RX WTRU may transmit a PSICH transmission to the TX WTRU with the highest measured RSRP value that is higher than a (e.g., (pre-)configured) RSRP threshold.

[0175] The RX WTRU may determine, for example, the TX WTRU and corresponding information for PSICH transmission based on the distance between the RX WTRU and the TX WTRU with which the reserved and conflicting resources are associated. The RX WTRU may determine, for example, which TX WTRU transmits a conflict indication transmission (e.g., in a PSICH transmission) based on the calculated TX-RX distances between the RX WTRU and each TX WTRU with which the reserved and conflicting resources are associated. The RX WTRU may calculate the TX-RX distance, for example, based on the region 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, the RX WTRU may transmit a PSICH transmission to the TX WTRU. In an example, the RX WTRU may transmit a PSICH transmission to the TX WTRU with the minimum TX-RX distance and within the MCR indicated in the SCI from the TX WTRU.

[0176] The RX WTRU may determine, for example, the TX WTRU and corresponding information for PSICH transmission based on the type of conflict detected in the conflicting resources. For example, if (e.g., when) the RX WTRU detects a same time slot conflict (e.g., as described herein with respect to the RX WTRU determining a same time slot conflict due to overlapping resource reservations), the RX WTRU may determine to transmit a PSICH transmission or a PSFCH transmission to the TX WTRU. The PSICH transmission may include an indication of a retransmission of the TB transmitted by the TX WTRU in the conflicting resources.

[0177] For example, if (e.g., when) the RX WTRU detects a conflict due to a previously received resource reservation (e.g., as described herein with respect to the RX WTRU determining a conflict due to a previously received resource reservation), the RX WTRU may determine to transmit a conflict indication transmission (e.g., a PSICH transmission). The RX WTRU may determine to transmit 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 resources (e.g., if (e.g., when) the RX WTRU detects a conflict due to a previously received resource reservation). The RX WTRU may transmit a conflict indication transmission to the TX WTRU with the highest priority indicated in the SCI of the reserved and conflicting resources.

[0178] 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 with respect to the RX WTRU determining a conflict due to its scheduled SL or UL transmission), 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 for the SL or UL transmission is higher than the priority indicated in the SCI of the reserved resources, 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 indicate resource reselection in the PSICH transmission. For example, if (e.g., when) the priority of the TB for the SL or UL transmission is lower than the priority indicated in the SCI of the reserved resources, the RX WTRU may determine to suppress sending (e.g., not send) the PSICH transmission and discard the SL or UL transmission and receive the SL TB in the reserved resources (e.g., as indicated in the SCI from the TX WTRU). A higher priority may correspond to a smaller numerical value in the priority bit field of the SCI.

[0179] The RX WTRU may determine the PSICH transmission format and / or resources. The WTRU may receive configuration information indicating (e.g., (pre)-configured by a higher layer with) one or more of, for example, the following for the conflict indication transmission: the PSICH transmission format; the PSFCH transmission format; and / or the PSICH transmission resource configuration.

[0180] The WTRU may receive configuration information indicating (e.g., (pre)-configured with) the PSICH transmission format. In some examples, the PSICH transmission format may be based on a sequence, such as a Zadoff Chu (ZC) sequence. The WTRU may generate a PSICH transmission sequence (e.g., a ZC sequence cyclic shift value) and / or convey SL conflict detection and indication information in the selected PSICH transmission sequence. The PSICH transmission format may include one or more (e.g., multiple) bit fields. (For example, each) bit field may include (e.g., (pre)-configured with) a set of code points. The WTRU may use the code point values in the PSICH transmission bit fields to indicate relevant information.

[0181] In some examples, for instance, if (e.g., when) an SL resource conflict is detected in a resource, the PSICH transmission may indicate information applicable to the resource reserved in the received SCI. The PSICH transmission may indicate, for example, one or more of the following: an indication of a retransmission of an SL TB transmitted in a PSSCH transmission associated with the received SCI; an indication for canceling a retransmission of an SL TB scheduled in the resource reserved in the received SCI; an indication of a one-time resource reselection (e.g., reselection of a single resource reserved in the received SCI), such as an indication of an initial transmission of a (e.g., new) SL TB associated with the same WTRU source and / or destination ID as indicated in the received SCI and / or a retransmission of an SL TB transmitted in the PSSCH associated with the received SCI; and / or a request for a periodic reselection (e.g., reselection of a resource periodically reserved in the received SCI), such as a request for an initial transmission and retransmission of a (e.g., new) SL TB associated with the same WTRU source and / or destination ID as indicated in the received SCI.

[0182] In some examples, the WTRU may include SL resource conflict and / or indication information (e.g., together with HARQ feedback information) (e.g., if / when HARQ is enabled for the SL TB) for the resources reserved in the received SCI in a PSFCH transmission format. The PSFCH transmission format may indicate, for example, one or more of the following: a HARQ ACK for an SL TB transmitted in a PSSCH transmission associated with the received SCI; a HARQ NACK for an SL TB transmitted in a PSSCH transmission associated with the received SCI and / or an indication of a HARQ retransmission in the resource reserved in the received SCI; and / or an indication of a HARQ NACK for an SL TB transmitted in a PSSCH transmission associated with the received SCI and / or a HARQ retransmission with resource reselection (e.g., a HARQ retransmission in a resource different from the resource reserved in the received SCI due to a detected conflict).

[0183] For example, if (e.g., when) the RX WTRU detects a conflict in the resource reserved for a HARQ retransmission, the RX WTRU may indicate a HARQ NACK and a resource reselection in a PSFCH transmission.

[0184] The WTRU may receive configuration information indicating (e.g., pre - configured with) PSICH resources. (For example, each) resource may include, for example, a PSICH transmission occasion, PSICH frequency resources, and / or a PSICH sequence. In some examples, the PSICH transmission occasion may be an SL time slot. For example, the number of periodic SL time slots in a resource pool may be indicated (e.g., pre - configured) as the PSICH transmission occasion. The WTRU may perform PSICH transmission at one or more (e.g., multiple) indicated (e.g., pre - configured) PSICH symbols within the PSICH transmission occasion, e.g., where no PSSCH / PSCCH transmission may be performed. For example, if (e.g., when) no PSICH transmission occasion is indicated (e.g., pre - configured) in the resource pool, conflict detection and indication may be disabled in the resource pool.

[0185] In some examples, the PSICH transmission may be based on (e.g., a single) physical resource block (PRB), e.g., for a sequence - based PSICH transmission format. The number of PRBs may be indicated (e.g., pre - configured) in the resource pool for PSICH transmission. A set of orthogonal sequences (e.g., ZC sequences with different cyclic shifts) may be indicated (e.g., pre - configured). Multiple PSICH transmissions may be code - domain multiplexed within a (e.g., one) PSICH transmission occasion. The PSICH resources may (e.g., thus) be identified using an index based on the PRB and / or the sequence used in the PRB.

[0186] The RX WTRU may determine, for example, based on one or more of the following, the resources for PSICH transmission to the determined TX WTRU in the determined PSICH transmission occasion: the WTRU source / destination ID of the determined TX WTRU (e.g., WTRU ID );the index of the SL time slot in which the SCI for reserved resources was received (e.g., Index slot );the index of the SL time slot of the determined PSICH transmission occasion (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.

[0187] In some examples, the RX WTRU may determine the index of the PSICH resource corresponding to the reserved resources (e.g., as WTRU ID +Index slot )MOD(N PSICH_resource )。N PSICH_resourceIt can be the sum of PSICH resource sets determined within the PRBs of the PSSCH subchannel and / or within the PRBs of the PSCCH subchannel reserved for collision detection.

[0188] In some examples, the 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-based PSICH transmission at (e.g., (pre-)configured) symbols within the PSICH transmission occasion.

[0189] The RX WTRU can determine the PSICH transmission power and concurrent PSICH and PSFCH transmissions. The RX WTRU can receive configuration information indicating one or more of the following for (e.g., a single) PSICH transmission and concurrent PSICH and / or PSFCH transmissions: PSICH transmission power offset (P 0_PSICH ); path loss compensation factor (α); downlink path loss (DLPL); SL path loss (SLDL); maximum total number of concurrent PSICH and / or PSFCH transmissions (N max ); SCS parameter set (u); (e.g., (pre-)configured) maximum SL power (P SL_MAX ); and / or if (e.g., when) the measured SL CBR exceeds (e.g., (pre-)configured) CBR threshold, (e.g., (pre-)configured) maximum SL power (P SL_MAX_CBR ).

[0190] The RX WTRU can select which path loss to apply to the PSICH transmission power setting (e.g., as described herein), for example, based on the TX WTRU selected for the PSICH transmission. The RX WTRU can set the power (P PSICH,single ) of the PSICH transmission to one of the following: downlink path loss (DLPL) of the single PSICH transmission power setting; and / or SL path loss (SLPL) of the single PSICH transmission power setting.

[0191] 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 the TX WTRU is not associated with the V2X service and / or SL application subscribed by the RX WTRU, the RX WTRU may determine to use the downlink path loss (DLPL) for a single PSICH power setting. The RX WTRU may estimate the DLPL, for example, based on the downlink RS (e.g., the same) estimated for PUSCH transmission. The RX WTRU may set the single PSICH transmission power to one of the following: P PSICH,single = minimum(P SL_MAX , P 0_PSICH + 10log10(2 u ) + Alpha * DLPL) dBm; P PSICH,single = minimum(P SL_MAX_CBR , P 0_PSICH + 10log10(2 u ) + Alpha * DLPL) dBm. For example, if (e.g., when) the RX WTRU measures that the SL CBR is higher than the (e.g., pre-)configured CBR threshold; or if the RX WTRU is outside the NW coverage, the RX WTRU may apply the (pre-)configured maximum SL power as follows: P PSICH,single = P SL_max dBm and P PSICH,single = P SL_max_CBR dBm (e.g., if / when the RX WTRU measures that the SL CBR is higher than the (pre-)configured CBR threshold).

[0192] 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 the TX WTRU is associated with the V2X service and / or SL application subscribed by the RX WTRU, the RX WTRU may determine to use the SL path loss (SLPL) for a single PSICH power setting. The RX WTRU may estimate the DLPL, for example, based on the downlink RS (e.g., the same) estimated for PUSCH transmission. The RX WTRU may 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 an estimated SL path loss based on SL RS, such as SL CSI-RS, PSCCH DMRS, and / or PSSCH DMRS transmitted by the TX UE for which PSICH transmission is targeted) or P PSICH,single = minimum ( P SL_MAX_CBR , P 0_PSICH + 10 log10 ( 2 u ) + Alpha * SLPL ) dBm (e.g., if / when the RX WTRU measures the SL CBR to be higher than a (pre-)configured CBR threshold).

[0193] The PSICH transmission opportunity may (e.g., fully) overlap with the PSFCH transmission opportunity. The RX WTRU may perform concurrent PSICH and PSFCH transmissions at (e.g., the same) symbol positions within the SL time slot. The RX WTRU may receive configuration information indicating the (e.g., maximum) total number (N max ) of PSICH and PSFCH transmissions at (e.g., one) PSFCH and / or PSICH transmission opportunity (e.g., (pre-)configured). The RX WTRU may perform prioritization to determine which PSICH and / or PSFCH transmissions to perform. The prioritization performed may be associated with one or more of the following: available maximum power, the determined / scheduled PSICH and / or PSFCH transmissions; the actual number of PSICH / PSFCH transmissions.

[0194] For example, if (e.g., when) the RX WTRU measures the SL CBR to be higher than (e.g., (pre-)configured) threshold, the RX WTRU may determine the available maximum power as P max or P max CBR .

[0195] For example, if (e.g., when) the number of determined and / or scheduled PSICH and / or PSFCH transmissions (e.g., N scheduled ) is less than or equal to (e.g., (pre-)configured) maximum number (e.g., N max ) and the total power is less than or equal to the determined available maximum power, the RX WTRU may perform (e.g., all, such as N scheduled ) the determined and / or scheduled PSICH and / or PSFCH transmissions.

[0196] The RX WTRU may perform prioritization of the determined and / or scheduled ( N scheduled ) PSICH / PSFCH transmissions, and may, for example, based on the number ( N scheduled) whether it is less than or equal to a (e.g., (pre-)configured) maximum number (N max ) and whether the total power is greater than the determined available maximum power, or the number (N scheduled ) of the determined and / or scheduled PSICH and / or PSFCH transmissions is greater than a (e.g., (pre-)configured) maximum number (N max ) to determine the actual number (N actual ) of PSICH / PSFCH transmissions. The RX WTRU may determine, for example, based on the SL priority associated with the PSICH and / or PSFCH transmissions, to perform the actual number (N actual ) of PSICH and / or PSFCH transmissions in descending priority order (e.g., in ascending priority indication value order) (e.g., which may be less than the scheduled number). The priority may be indicated in the SCI reserving the resources corresponding to the PSICH transmission and the SCI associated with the PSSCH corresponding to the PSFCH transmission. The RX WTRU may determine such actual number (N actual ) such that the sum of the determined PSICH and / or PSFCH transmission powers is less than or equal to the determined available maximum power. The RX WTRU may preferentially allocate the available power to the PSICH / PSFCH transmissions with the highest SL priority and discard the transmissions with the lowest priority.

[0197] The RX WTRU may determine to perform a resource information transmission to the TX WTRU. In an example, the RX WTRU may determine to transmit to the TX WTRU a (e.g., explicit) set of resources where there is a conflict. In an example, the RX WTRU may determine such resources where there is a conflict, for example, based on the excluded resources determined by the RX WTRU through sensing, the resources reserved in the previously received SCI (e.g., as described herein with respect to the RX WTRU determining a conflict due to a previously received resource reservation), and the resources scheduled / reserved for the RX WTRU's own transmission (e.g., as described herein with respect to the RX WTRU determining a conflict due to its scheduled SL or UL transmission).

[0198] In conflict-related information transmission, the RX WTRU may include WTRU source and / or destination IDs associated with a resource set in which a conflict exists. 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. The RX WTRU may include source and destination IDs assigned to unicast transmission (e.g., via a higher layer, such as higher layer signaling), e.g., for unicast transmission between the TX WTRU and the RX WTRU. The RX WTRU may include a destination ID assigned to multicast and broadcast transmission (e.g., via a higher layer, such as higher layer signaling), e.g., for multicast and broadcast transmission.

[0199] The RX WTRU may determine (e.g., all) resources in which a conflict exists, e.g., during a resource selection window. The RXWTRU may indicate such a resource selection window in a (e.g., explicit) request for a resource set from the TX WTRU. In an example, the RX WTRU may receive configuration information indicating (e.g., being (pre)-configured with) a resource selection window for determining resources in which a conflict exists. The RX WTRU may include resource selection window information in a resource set transmitted to the TX WTRU, for example. The RX WTRU may include its area ID and / or the SL RSRP value measured on a (e.g., explicit) request from the TX WTRU and / or the SCI of a previous resource in a reserved resource set.

[0200] The behavior of the SCI-decoded RX WTRU may be based on the transmission of resource information to the TX WTRU. The RX WTRU may receive configuration information indicating (e.g., being (pre)-configured with) PSCCH candidate resources, which may include a plurality of (e.g., consecutive) symbols starting from the second SL symbol in an SL time slot of an SL resource pool and / or a plurality of PRBs starting from the lowest PRB of a sub-channel of an SL resource pool.

[0201] The RX WTRU may receive configuration information indicating (e.g., being (pre-)configured with) the PSCCH decoding resource allocation. The allocation may be, for example, multiple sub-channels of a resource pool, a resource pool, or a set of resource pools. (For example, multiple) resource pools may be located in (e.g., one) SL BWP or different SL BWPs. The SL BWP may be located in different SL carriers. The RX WTRU may be (pre-)configured with a set of such PSCCH decoding resource allocations, and (for example, each such) source allocation may 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 service) subscribed by the RX WTRU; the power saving state (e.g., the ACTIVE state, the ON duration, the INACTIVE state, the OFF duration); or the WTRU capability and / or type (e.g., a RedCap WTRU with a small bandwidth).

[0202] The RX WTRU may determine the PSCCH decoding resource allocation, for example, based on the resources provided to the TX WTRU. In an example, the PSCCH may determine to exclude the PSCCH candidate resources within the resources provided to the TX WTRU from the PSCCH decoding resource allocation. For example, the SL time slots and sub-channels included in the conflicting resource sets provided to the TX WTRU may be suppressed from being monitored (e.g., not monitored) by the RX WTRU for SCI decoding of transmissions from the TX WTRU.

[0203] In an example, the RX WTRU may send (e.g., an explicit) set of resources (e.g., a conflict-free set of resources) to be applied to the TX WTRU. The RX WTRU may prioritize the SCI decoding of the PSCCH candidate resources within the SL time slots and sub-channels included in the resources provided to the TX WTRU.

[0204] The RX WTRU may perform the exclusion and / or prioritization of the PSCCH candidate resources (e.g., as described herein) during a resource selection window indicated in the set of resources sent to the TX WTRU. The RX WTRU may provide such a set of resources to different TX WTRUs. The RX WTRU may determine which PSCCH candidate resources to exclude and / or prioritize in (e.g., each) SL time slot, for example, based on the semi-persistent resource reservation performed by each TX WTRU in the SL time slot.

[0205] The TX WTRU may determine that conflict detection and indication can be performed for the resource reservation indicated in the SCI associated with the executed SL transmission. The determination may be based on, for example, one or more of the following (e.g., as may be configured herein with respect to SL resource conflict and indication (pre - )): a subset of the WTRU source ID and / or destination ID; an SL priority threshold (e.g., Prio thre ); an enable / disable indication for WTRU - to - WTRU coordination and / or conflict detection (e.g., ConflictDetEnabled); and / or an enable / disable indication for WTRU - to - WTRU coordination and / or conflict indication (e.g., ConflictIndEnabled).

[0206] The TX WTRU may determine the corresponding PSICH transmission occasion for PSICH monitoring for the (e.g., each) reserved resource, e.g., as described herein (e.g., with respect to the RX WTRU determination of the conflict detection occasion for the resources reserved in the received SCI). The TX WTRU and the RX WTRU may identify the same PSICH transmission occasion for the resources received in the received SCI. The TX WTRU may determine the corresponding PSICH transmission occasion for PSICH monitoring for the (e.g., each) reserved resource based on, for example, one or more of the following: the conflict detection processing time (e.g., T proc ); and / or the conflict indication transmission processing time (e.g., T PSICH ).

[0207] For example, the TX WTRU may determine the PSICH resources (e.g., as determined by the RX WTRU herein according to the PSICH transmission format and resources) based on one or more of the following: the WTRU source and / or destination ID indicated in the SCI of the reserved resources; the index of the SL time slot of the SCI transmission (e.g., Index slot ); the index of the SL time slot of the determined PSICH transmission occasion (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.

[0208] For example, if (e.g., when) the TX WTRU determines that collision detection and indication are enabled for resource reservation transmitted in the SCI, the TX WTRU may monitor the PSICH transmission using the determined resources at the determined PSICH transmission occasion. The TX WTRU may (e.g., if / when the TX WTRU does not receive the PSICH transmission) disable preemption for the reserved resources (e.g., if preemption is (pre-)configured in the resource pool) and / or may perform an initial transmission and / or retransmission in the reserved resources. Preemption may detect a collision of the reserved resources at the TX WTRU. Detecting a collision at the RX WTRU may not be sufficient for the TX WTRU to skip preemption and reduce processing.

[0209] The TX WTRU may (e.g., if / when the TX WTRU receives the PSICH transmission) disable 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 the information indicated in the PSICH for (each) reserved resource): stop retransmission (e.g., if / when the PSICH indicates cancellation of retransmission); perform reselection for non-periodic reserved resources and / or for (e.g., one) period of periodic reserved resources (e.g., if / when the PSICH indicates a one-time resource collision and / or reselection); perform reselection for one or more (e.g., all) periods of periodic reserved resources (e.g., if / when the PSICH indicates a periodic resource collision and / or reselection); and / or perform retransmission if / when the PSICH transmission indicates retransmission.

[0210] The TX WTRU may determine the colliding resources, for example, based on multiple received sets of colliding resources. In an example, the TX WTRU may receive transmissions from multiple RX WTRUs, and each transmission may include (e.g., explicit) a set of resources. The TX WTRU may determine which set of resources is used for the SL transmission, for example, based on the information included in the set of resources from the RX WTRU and / or the parameters of the SL transmission of the TX WTRU. The information included in the set of resources from the RX WTRU may include the WTRU source and / or destination ID, the resource selection window, the area ID, and / or the SL RSRP measured at the TX WTRU.

[0211] The parameters of the SL transmission of the TX WTRU may include the WTRU source and / or destination ID associated with the TB to be transmitted, the MCR of the TB to be transmitted, and / or the resource selection window.

[0212] In an example, when one or more of the following conditions are met, the TX WTRU may determine to apply a resource set: the WTRU source and / or destination ID indicated in the received resource set is the same as the source and / or destination ID associated with the SL TB to be transmitted; the TX-RX distance (e.g., calculated based on the area ID indicated in the received resource set 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 set 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 set overlaps with the resource selection window determined for the TB to be transmitted.

[0213] The TX WTRU may accordingly determine a resource set for resource selection applied to SL TB transmission (e.g., multiple received resource sets). In an example, the TX WTRU may determine a resource combination to include non-overlapping resources that the TX WTRU may select from each of the determined received resource sets. The TX WTRU may select resources from the overlapping portion between the indicated resource selection window and the determined resource selection window of the TB to be transmitted.

[0214] Although the above features and elements have been described in specific combinations, each feature or element may be used alone without the other features and elements of the preferred embodiment, or in various combinations with or without other features and elements.

[0215] Although the specific implementations described herein may consider 3GPP specific protocols, it should be understood that the specific implementations described herein are not limited to such scenarios and may be applicable to other wireless systems. For example, although the solutions described herein consider 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 are also applicable to other wireless systems.

[0216] The processes described above may be implemented in a computer program, software, and / or firmware incorporated in a computer-readable medium for execution by a computer and / or processor. Examples of computer-readable media include, but are not limited to, electronic signals (transmitted via wired 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), registers, cache memory, semiconductor memory devices, magnetic media (such as, but not limited to, internal hard disks and removable disks), magneto-optical media, and optical media (such as compact disc (CD)-ROM disks and / or digital versatile disc (DVD)). A processor associated with the software may be used to implement a radio frequency transceiver for a WTRU, terminal, base station, RNC, and / or any host computer.

Claims

1. A first wireless transmit / receive unit (WTRU), the first WTRU comprising: A processor, the processor being configured to: Receive configuration information indicating a conflict detection processing time, wherein the conflict detection processing time is the minimum time for reporting a conflict indication; Receive a first sidelink control information (SCI) from a second WTRU, wherein the first SCI indicates a first conflict indication setting and at least a first resource; Receive a second SCI from a third WTRU, wherein the second SCI indicates a second conflict indication setting and at least a second resource; Determine that the first SCI and the second SCI are received at a time before a physical sidelink feedback channel (PSFCH) transmission, wherein the time before the PSFCH transmission is at least the conflict detection processing time before the PSFCH transmission; Determine that the at least first resource and the at least second resource overlap; And Transmit the PSFCH transmission including a conflict indication to the second WTRU, at least based on a determination that the first conflict indication setting is enabled.

2. The first WTRU according to claim 1, wherein, The processor is further configured to: Determine a measurement result associated with the second SCI; And Based on the determination that the at least first resource and the at least second resource overlap and based on a determination that the measurement result associated with the second SCI is greater than a first threshold, determine that there is a conflict associated with the first resource and the second resource.

3. The first WTRU according to claim 2, wherein, The measurement result associated with the second SCI is a reference signal received power (RSRP).

4. The first WTRU according to claim 1, wherein, The conflict detection processing time is a duration associated with conflict detection performed by the first WTRU and conflict indications sent by the first WTRU.

5. The first WTRU according to claim 1, wherein, The determination that the at least first resource and the at least second resource overlap is based on a determination that the first resource at least partially overlaps with the second resource.

6. The first WTRU according to claim 1, wherein, The processor is further configured to: Determine a conflict detection trigger timing at least based on the conflict detection processing time and the first resource, wherein the second SCI is received during the conflict detection trigger timing.

7. The first WTRU according to claim 6, 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 indicating a second conflict detection processing time associated with the second WTRU, wherein the conflict detection trigger timing is further determined based on the second conflict detection processing time associated with the second WTRU.

8. The first WTRU according to claim 1, wherein, The transmitted PSFCH transmission is further based on the determination that the first SCI and the second SCI are received at the time before the PSFCH transmission.

9. The first WTRU according to claim 1, wherein, The transmitted PSFCH transmission is further based on a determination that the second conflict indication setting is disabled.

10. A method, the method comprising: Receiving configuration information indicating a conflict detection processing time, wherein the conflict detection processing time is the minimum time for reporting a conflict indication; Receiving first sidelink control information (SCI) from a first wireless transmit / receive unit (WTRU), wherein the first SCI indicates a first conflict indication setting and at least a first resource; Receive a second SCI from a second WTRU, wherein the second SCI indicates a second conflict indication setting and at least a second resource; Determine that the first SCI and the second SCI are received at a time before a physical sidelink feedback channel (PSFCH) transmission, wherein the time before the PSFCH transmission is at least the conflict detection processing time before the PSFCH transmission; Determine that the at least first resource and the at least second resource overlap; and Send the PSFCH transmission including the conflict indication to the first WTRU, at least based on the determination that the first conflict indication setting is enabled.

11. According to the method of claim 10, wherein, The method further includes: Determine a measurement result associated with the second SCI; and Based on the determination that the at least first resource and the at least second resource overlap and based on the determination that the measurement result associated with the second SCI is greater than a first threshold, determine that there is a conflict associated with the first resource and the second resource.

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

13. According to the method of claim 10, wherein, The conflict detection processing time is the duration associated with the conflict detection performed by the first WTRU and the conflict indication sent by the first WTRU.

14. According to the method of claim 10, wherein, The determination that the at least first resource and the at least second resource overlap is based on the determination that the first resource at least partially overlaps with the second resource.

15. According to the method of claim 10, wherein, The method further includes: Determine a conflict detection trigger timing at least based on the conflict detection processing time and the first resource, wherein the second SCI is received during the conflict detection trigger timing.

16. According to the method of claim 15, 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 conflict detection trigger timing is further determined based on the second conflict detection processing time associated with the first WTRU.

17. According to the method of claim 10, wherein, The sent PSFCH transmission is further based on the determination that the first SCI and the second SCI are received at the time before the PSFCH transmission.

18. According to the method of claim 10, wherein, The sent PSFCH transmission is further based on the determination that the second conflict indication setting is disabled.

19. A first wireless transmit / receive unit (WTRU), the first WTRU comprising: A processor, configured to: Receive configuration information indicating a collision detection processing time, wherein the collision detection processing time is the minimum time for reporting a collision indication; Receive a first sidelink control information (SCI) from a second WTRU, wherein the first SCI indicates a first resource, a first conflict indication setting, and a first priority value, wherein the first conflict indication setting indicates whether the second WTRU supports receiving conflict information; Receive a second SCI from a third WTRU, wherein the second SCI indicates a second resource, a second conflict indication setting, and a second priority value, wherein the second conflict indication setting indicates whether the third WTRU supports receiving conflict information; Determine that the first SCI and the second SCI are received at a time before a physical sidelink feedback channel (PSFCH) transmission, wherein the time before the PSFCH transmission is at least the conflict detection processing time before the PSFCH transmission; Determine that the at least first resource and the at least second resource overlap; Determine a reference signal received power (RSRP) threshold based on the first priority value and the second priority value; Determine that the RSRP measurement result associated with the second SCI is greater than the RSRP threshold; Based on the determination of the overlap of the at least first resource and the at least second resource and based on the determination that the RSRP measurement result associated with the second SCI is greater than the RSRP threshold, it is determined that there is a conflict associated with the first resource and the second resource; And Based on the determination of the overlap of the at least first resource and the at least second resource, based on the determination that the first conflict indication setting is enabled and the second conflict indication setting is disabled, or based on the determination that the first conflict indication setting is enabled, the second conflict indication setting is enabled, and the first priority value is greater than the second priority value, send the PSFCH transmission including the conflict indication to the second WTRU.

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