Method and apparatus for side link inter-wireless transmit / receive unit (WTRU) coordination

Abstract

To provide methods, apparatuses, systems, architectures, and interfaces for a WTRU performing side link communications.SOLUTION: The present method may include any of: receiving SL transmission configuration information indicating (1) a dedicated resource allocation for assistance transmissions, and (2) triggering conditions for performing an assistance transmission; on condition that (i) a physical SL shared channel (PSSCH) transmission is received, by the WTRU from another WTRU, according to a semi-persistent reservation, and (ii) one or more of the triggering conditions for performing the assistance transmission has occurred, (a) performing sensing based on sensing parameters associated with the received PSSCH transmission, and (b) selecting a dedicated resource allocation according to a resource of the received PSSCH transmission; and transmitting, to any number of proximate WTRUs, an assistance transmission using the selected dedicated resource allocation, the assistance transmission including assistance information associated with the sensing performed by the WTRU.SELECTED DRAWING: Figure 2

Description

[Background technology]

[0001] The present invention relates to the field of communications, and more particularly to methods, apparatus, systems, architectures, and interfaces for communication in advanced or next generation wireless communication systems, including communications performed using New Radio and / or New Radio (NR) access technologies and communication systems. NR access technologies and communication systems may include (e.g., may be used for) vehicular communications (V2X), for example, for communication between any of automobiles on a roadway, infrastructure, pedestrians, and / or networks, in which wireless transmit / receive units (WTRUs) may communicate with each other (e.g., directly).

[0002] V2X scenarios include (1) in-coverage scenarios, where a WTRU may receive assistance from the network to start transmitting and receiving vehicular communication messages, and (2) out-of-coverage scenarios, where a WTRU may start transmitting and receiving vehicular communication messages using pre-configured parameters. V2X services include: (1) vehicle-to-vehicle (V2V): vehicular WTRUs may communicate directly with each other; (2) vehicle-to-infrastructure (V2I): vehicular WTRUs may communicate with either roadside units (RSUs) or base stations (BSs), such as evolved NodeBs (eNBs) or other access points; (3) vehicle-to-network (V2N): vehicular WTRUs may communicate with a core network; and (4) vehicle-to-pedestrian (V2P): vehicular WTRUs may communicate with UEs associated with pedestrians under specific and / or special conditions, e.g., under low battery capacity. Furthermore, V2X use cases may include evolved mobile broadband (eMBB), massive machine-type communications (mMTC), and ultra-reliable low-latency communications (URLLC). Different use cases may focus on different requirements, such as higher data rates, higher spectral efficiency, lower power and higher energy efficiency, shorter latency, and higher reliability. [Brief description of the drawings]

[0003] A more detailed understanding may be had from the following description, given by way of example in conjunction with the accompanying drawings, in which like reference numbers indicate similar elements and in which: [Figure 1A] FIG. 1 is a system diagram illustrating an example communication system in which one or more disclosed embodiments may be implemented. [Figure 1B] 1A is a system diagram illustrating an example wireless transmit / receive unit (WTRU) that may be used within the communications system illustrated in FIG. 1A, according to one embodiment. [Figure 1C] FIG. 1B is a system diagram illustrating an example radio access network (RAN) and an example core network (CN) that may be used within the communication system illustrated in FIG. 1A, according to one embodiment. [Figure 1D] FIG. 1B is a system diagram illustrating a further exemplary RAN and a further exemplary CN that may be used within the communication system illustrated in FIG. 1A, according to one embodiment. [Diagram 2] FIG. 1 illustrates assistance information transmission triggered by an explicit request according to an embodiment. [Diagram 3] FIG. 1 illustrates assistance information transmission triggered by semi-persistent (SP) based resource reservation according to an embodiment. [Figure 4] A diagram showing assisted transmission triggered by either HARQ ACK / NACK transmission and HARQ retransmission according to an embodiment. [Diagram 5] FIG. 1 illustrates an assistance transmission providing resource set information according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0004] Exemplary Network for Implementing the Embodiments 1A illustrates an example communication system 100 in which one or more disclosed embodiments may be implemented. The communication system 100 may be a multiple access system that provides content, such as voice, data, video, messaging, broadcasts, etc., to multiple wireless users. The communication system 100 may enable the multiple wireless users to access such content through 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.

[0005] 1A, communications system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, RAN 104 / 113, CN 106 / 115, public switched telephone network (PSTN) 108, Internet 110, and other networks 112, although it will be understood that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network elements. Each of WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and / or communicate in a wireless environment. By way of example, the WTRUs 102a, 102b, 102c, 102d, any of which may be referred to as a “station” and / or “STA,” may be configured to transmit and / or receive wireless signals and may include user equipment (UE), mobile stations, fixed or mobile subscriber units, subscription-based units, pagers, cellular phones, personal digital assistants (PDAs), smartphones, laptops, netbooks, personal computers, wireless sensors, hotspots or Mi-Fi devices, Internet of Things (IoT) devices, watches or other wearables, head-mounted displays (HMDs), vehicles, drones, medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in an industrial and / or automated processing chain context), consumer electronics devices, devices operating in commercial and / or industrial wireless networks, etc. Any of the WTRUs 102a, 102b, 102c, and 102d may be referred to interchangeably as a UE.

[0006] The communication system 100 may also include a base station 114a and / or a base station 114b. Each of the base stations 114a, 114b may be any type of device configured to wirelessly interface with at least one of the WTRUs 102a, 102b, 102c, 102d to facilitate access to one or more communication networks, such as the CN 106 / 115, the Internet 110, and / or other networks 112. By way of example, the base stations 114a, 114b may be a base transceiver station (BTS), a Node B, an eNodeB, a Home Node B, a Home eNodeB, a gNB, a NR NodeB, a site controller, an access point (AP), a wireless router, etc. Although the base stations 114a, 114b are each shown as a single element, it will be understood that the base stations 114a, 114b may include any number of interconnected base stations and / or network elements.

[0007] The base station 114a may be part of the RAN 104 / 113, which may also include other base stations and / or network elements (not shown), such as a base station controller (BSC), a radio network controller (RNC), a relay node, etc. The base station 114a and / or the base station 114b may be configured to transmit and / or receive wireless signals on one or more carrier frequencies, which may be referred to as a cell (not shown). These frequencies may be licensed spectrum, unlicensed spectrum, or a combination of licensed and unlicensed spectrum. A cell may provide wireless service coverage for a particular geographic area, which may be relatively fixed or may change over time. A cell may be further divided into cell sectors. For example, the cell associated with the base station 114a may be divided into three sectors. Thus, in one embodiment, the base station 114a may include three transceivers, i.e., one transceiver for each sector of the cell. In one embodiment, the base station 114a may employ multiple-input multiple output (MIMO) technology and may utilize multiple transceivers for each sector of the cell, for example, using beamforming to transmit and / or receive signals in a desired spatial direction.

[0008] The base stations 114a, 114b may communicate with one or more of the WTRUs 102a, 102b, 102c, 102d over an air interface 116, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet (UV), visible light, etc.). The air interface 116 may be established using any suitable radio access technology (RAT).

[0009] More specifically, as noted above, the communications system 100 may be a multiple access system and may use one or more channel access schemes, such as, for example, CDMA, TDMA, FDMA, OFDMA, SC-FDMA, etc. For example, the base stations 114a and the WTRUs 102a, 102b, 102c in the RAN 104 / 113 may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may establish the air interface 115 / 116 / 117 using wideband CDMA (WCDMA). WCDMA may include communications protocols such as High-Speed ​​Packet Access (HSPA) and / or Evolved HSPA (HSPA+). HSPA may include High-Speed ​​Downlink (DL) Packet Access (HSDPA) and / or High-Speed ​​Uplink Packet Access (HSUPA).

[0010] In one embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which may establish the air interface 116 using Long Term Evolution (LTE) and / or LTE-Advanced (LTE-A) and / or LTE-Advanced Pro (LTE-A Pro).

[0011] In one embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as NR radio access, which may establish the air interface 116 using New Radio (NR).

[0012] In one embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement multiple radio access technologies. For example, the base station 114a and the WTRUs 102a, 102b, 102c may implement LTE radio access and NR radio access together, e.g., using dual connectivity (DC) principles. Thus, the air interface utilized by the WTRUs 102a, 102b, 102c may be characterized by multiple types of radio access technologies and / or transmissions transmitted to / from multiple types of base stations (e.g., eNBs and gNBs).

[0013] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement a wireless technology such as IEEE 802.11 (i.e., Wireless Fidelity, WiFi), IEEE 802.16 (i.e., Worldwide Interoperability for Microwave Access, WiMAX), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile communications (GSM), Enhanced Data rates for GSM Evolution (EDGE), GSM EDGE (GERAN), or the like.

[0014] 1A may be, for example, a wireless router, a Home Node B, a Home eNode B, or an access point, and may utilize any suitable RAT to facilitate wireless connectivity in a localized area, such as a location of a business, a home, a vehicle, a campus, an industrial facility, an air corridor (e.g., for use by drones), a road, etc. In one embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.11 to establish a wireless local area network (WLAN). In one embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.15 to establish a wireless personal area network (WPAN). In yet another embodiment, the base station 114b and the WTRUs 102c, 102d may establish a picocell or a femtocell using a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.). As shown in FIG. 1A, the base station 114b may 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.

[0015] The RAN 104 / 113 may communicate with the CN 106 / 115, which may be any type of network configured to provide voice, data, application, and / or voice over internet protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. The data may have various quality of service (QoS) requirements, such as, for example, 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, mobile location-based services, prepaid calling, Internet connectivity, video distribution, etc., and / or perform high-level security functions such as user authentication. 1A, it will be understood that the RAN 104 / 113 and / or the CN 106 / 115 may communicate, directly or indirectly, with other RANs employing the same RAT as the RAN 104 / 113 or a different RAT. For example, in addition to being connected to the RAN 104 / 113, which may utilize NR radio technology, the CN 106 / 115 may also communicate with another RAN (not shown) employing GSM, UMTS, CDMA2000, WiMAX, E-UTRA, or WiFi radio technology.

[0016] The CN 106 / 115 may also act as a gateway for the WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the Internet 110, and / or other networks 112. The PSTN 108 may include a public 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), user datagram protocol (UDP), and / or the internet protocol (IP) of the TCP / IP Internet protocol suite. The network 112 may include wired and / or wireless communication networks owned and / or operated by other service providers. For example, the network 112 may include another CN connected to one or more RANs, which may employ the same RAT as the RAN 104 / 113 or a different RAT.

[0017] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communications system 100 may include multi-mode capabilities (e.g., the WTRUs 102a, 102b, 102c, 102d may include multiple transceivers for communicating with different wireless networks over different wireless links). For example, the WTRU 102c shown in FIG. 1A may be configured to communicate with a base station 114a, which may use a cellular-based wireless technology, and a base station 114b, which may use an IEEE 802 wireless technology.

[0018] 1B is a system diagram illustrating an example WTRU 102. As shown in FIG. 1B, the WTRU 102 may include, among other things, a processor 118, a transceiver 120, a transmit / receive element 122, a speaker / microphone 124, a keypad 126, a display / touchpad 128, non-removable memory 130, removable memory 132, a power source 134, a global positioning system (GPS) chipset 136, and / or other peripherals 138. It will be understood that the WTRU 102 may include any sub-combination of the foregoing elements while remaining consistent with an embodiment.

[0019] The processor 118 may be a general purpose processor, a special purpose processor, a conventional processor, a digital signal processor (DSP), multiple microprocessors, one or more microprocessors associated with a DSP core, a controller, a microcontroller, an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) circuit, any other type of integrated circuit (IC), a state machine, etc. The processor 118 may perform signal coding, data processing, power control, input / output processing, and / or any other functionality that enables the WTRU 102 to operate in a wireless environment. The processor 118 may be coupled to the transceiver 120, which may be coupled to the transmit / receive element 122. Although FIG. 1B depicts the processor 118 and the transceiver 120 as separate components, it will be understood that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip.

[0020] The transmit / receive element 122 may be configured to transmit signals to or receive signals from a base station (e.g., base station 114a) over the air interface 116. For example, in one embodiment, the transmit / receive element 122 may be an antenna configured to transmit and / or receive RF signals. In one embodiment, the transmit / receive element 122 may be an emitter / detector configured to transmit and / or receive, for example, IR, UV, or visible light signals. In yet another embodiment, the transmit / receive element 122 may be configured to transmit and / or receive both RF and light signals. It will be appreciated that the transmit / receive element 122 may be configured to transmit and / or receive any combination of wireless signals.

[0021] 1B as a single element, the WTRU 102 may include any number of transmit / receive elements 122. More specifically, the WTRU 102 may use MIMO technology. Thus, in one embodiment, the WTRU 102 may include two or more transmit / receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals over the air interface 116.

[0022] The transceiver 120 may be configured to modulate signals transmitted by the transmit / receive element 122 and demodulate signals received by the transmit / receive element 122. As mentioned above, the WTRU 102 may have multi-mode capabilities. Thus, the transceiver 120 may include multiple transceivers to enable the WTRU 102 to communicate via multiple RATs, such as, for example, NR and IEEE 802.11.

[0023] The processor 118 of the WTRU 102 may be coupled to and may receive user-entered data from a speaker / microphone 124, a keypad 126, and / or a display / touchpad 128 (e.g., a liquid crystal display (LCD) display unit or an organic light-emitting diode (OLED) display unit). The processor 118 may also output user data to the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128. Additionally, the processor 118 may access information from and store data in any type of suitable memory, such as non-removable memory 130 and / or removable memory 132. The non-removable memory 130 may include random-access memory (RAM), read-only memory (ROM), a hard disk, or any other type of memory storage device. The removable memory 132 may include a subscriber identity module (SIM) card, a memory stick, a secure digital (SD) memory card, etc. In other embodiments, the processor 118 may access information and store data in memory that is not physically located on the WTRU 102, such as on a server or home computer (not shown).

[0024] The processor 118 may receive power from the power source 134, but may be configured to distribute and / or control the power to other components in the WTRU 102. The power source 134 may be any suitable device for providing power to the WTRU 102. For example, the power source 134 may include one or more dry batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, etc.

[0025] 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 a current location of the WTRU 102. In addition to or in lieu of information from the GPS chipset 136, the WTRU 102 may receive location information over the air interface 116 from a base station (e.g., base stations 114a, 114b) and / or determine its location based on the timing of signals being received from two or more nearby base stations. It will be understood that the WTRU 102 may obtain location information by way of any suitable location determination method while remaining consistent with an embodiment.

[0026] The processor 118 may further be coupled to other peripherals 138, which may include one or more software and / or hardware modules that provide additional features, functionality, and / or wired or wireless connectivity. For example, the peripherals 138 may include an accelerometer, an 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, a Bluetooth® module, a frequency modulated (FM) radio unit, a digital music player, a media player, a video game player module, an Internet browser, a virtual reality and / or augmented reality (VR / AR) device, an activity tracker, and the like. The peripherals 138 may include one or more sensors, which may be one or more of a gyroscope, an accelerometer, a Hall effect sensor, a magnetometer, an orientation sensor, a proximity sensor, a temperature sensor, a time sensor, a geolocation sensor, an altimeter, a light sensor, a touch sensor, a magnetometer, a barometer, a gesture sensor, a biometric sensor, and / or a humidity sensor.

[0027] The WTRU 102 may include a full-duplex radio where the transmission and reception of some or all of the signals (e.g., associated with a particular subframe for both the UL (e.g., for transmission) and the downlink (e.g., for reception)) may be parallel and / or simultaneous. The full-duplex radio may include an interference management unit to reduce and or substantially eliminate self-interference via hardware (e.g., chokes) or signal processing via a processor (e.g., via a separate processor (not shown) or processor 118). In one embodiment, the WRTU 102 may include a half-duplex radio for the transmission and reception of either some or all of the signals (e.g., associated with a particular subframe for either the UL (e.g., for transmission) or the downlink (e.g., for reception)).

[0028] 1C is a system diagram illustrating the RAN 104 and the CN 106 according to one embodiment. As mentioned above, the RAN 104 may communicate with the WTRUs 102a, 102b, 102c over the air interface 116 using E-UTRA radio technology. The RAN 104 may also communicate with the CN 106.

[0029] The RAN 104 may include eNode-Bs 160a, 160b, 160c, although it will be understood that the RAN 104 may include any number of eNode-Bs while remaining consistent with an embodiment. The eNode-Bs 160a, 160b, 160c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In an embodiment, the eNode-Bs 160a, 160b, 160c may implement MIMO technology. Thus, the eNode-B 160a may, for example, use multiple antennas to transmit wireless signals to and / or receive wireless signals from the WTRU 102a.

[0030] Each of the eNode-Bs 160a, 160b, 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the UL and / or DL, etc. As shown in FIG 1C, the eNode-Bs 160a, 160b, 160c may communicate with each other via an X2 interface.

[0031] 1C may include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (or PGW) 166. Although each of the foregoing elements is shown as part of the CN 106, it will be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0032] The MME 162 may be connected to each of the eNode-Bs 160a, 160b, and 160c in the RAN 104 via an S1 interface and may function as a control node. For example, the MME 162 may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, activating / deactivating bearers, selecting a particular serving gateway during initial attachment of the WTRUs 102a, 102b, 102c, etc. The MME 162 may provide a control plane function for switching between the RAN 104 and other RANs (not shown) that employ other radio technologies, such as GSM and / or WCDMA.

[0033] The SGW 164 may be connected to each of the eNode-Bs 160a, 160b, 160c in the RAN 104 via an S1 interface. The SGW 164 may generally route and forward user data packets to / from the WTRUs 102a, 102b, 102c. The SGW 164 may perform other functions, such as anchoring the user plane during inter-eNode-B handovers, triggering paging when DL data is available to the WTRUs 102a, 102b, 102c, and managing and storing the context of the WTRUs 102a, 102b, 102c.

[0034] The SGW 164 may be connected to a PGW 166, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices.

[0035] The CN 106 may facilitate communications with other networks. For example, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to circuit-switched networks, such as the PSTN 108, to facilitate communications between the WTRUs 102a, 102b, 102c and traditional land-line communications devices. For example, the CN 106 may include or communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that serves as an interface between the CN 106 and the PSTN 108. Additionally, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers.

[0036] Although the WTRU is depicted in FIGS. 1A-1D as a wireless terminal, it is contemplated that in certain representative embodiments such a terminal may use a wired communications interface (e.g., temporarily or permanently) with the communications network.

[0037] In an exemplary embodiment, the other network 112 may be a WLAN.

[0038] A WLAN in infrastructure Basic Service Set (BSS) mode may have an Access Point (AP) of the BSS and one or more stations (STAs) associated with the AP. The AP may have access or interface to a Distribution System (DS) or another type of wired / wireless network that carries traffic into and / or out of the BSS. Traffic originating from outside the BSS to the STAs may arrive through the AP and be delivered to the STAs. Traffic originating from the STAs to destinations outside the BSS may be sent to the AP and transmitted to the respective destination. Traffic between STAs in the BSS may be transmitted, for example, through the AP, where the source STA may transmit traffic to the AP, which may deliver the traffic to the destination STA. Traffic between STAs in the BSS may be considered and / or referred to as peer-to-peer traffic. Peer-to-peer traffic may be transmitted in a direct link setup (DLS) between the source STA and the destination STA (e.g., directly between them). In certain representative embodiments, the DLS may use 802.11e DLS or 802.11z tunneled DLS (TDLS). A WLAN using an Independent BSS (IBSS) mode may not have APs, and STAs within or using an IBSS (e.g., all of the STAs) may communicate directly with each other. The IBSS mode of communication may be referred to herein as an "ad-hoc" communication mode.

[0039] When using an 802.11ac infrastructure mode of operation or a similar mode of operation, an AP may transmit a beacon on a fixed channel, such as a primary channel. The primary channel may be a fixed width (e.g., a 20 MHz wide bandwidth) or a width that is dynamically set via signaling. The primary channel may be an operating channel of the BSS and may be used by STAs to establish a connection with the AP. In some representative embodiments, for example, in an 802.11 system, Carrier Sense Multiple Access / Collision Avoidance (CSMA / CA) with collision avoidance may be implemented. With CSMA / CA, STAs (e.g., all STAs), 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. One STA (e.g., only one station) may transmit at any given time in a given BSS.

[0040] A High Throughput (HT) STA may use a 40 MHz wide channel for communication, which may be formed, for example, through a combination of a primary 20 MHz channel and adjacent or non-adjacent 20 MHz channels.

[0041] A Very High Throughput (VHT) STA may support 20 MHz, 40 MHz, 80 MHz, and / or 160 MHz wide channels. The 40 MHz and / or 80 MHz wide 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 encoding, the data may pass through a segment parser that may split the data into two streams. Inverse Fast Fourier Transform (IFFT) processing and time domain processing may be performed separately on each stream. The streams may be mapped to two 80 MHz channels and the data may be transmitted by the transmitting STA. At the receiver of the receiving STA, the operations described above for the 80+80 configuration may be reversed and the combined data may be transmitted to the Medium Access Control (MAC).

[0042] Sub-1 GHz operating modes are supported by 802.11af and 802.11ah, where the channel operating bandwidths and carriers are reduced compared to those used in 802.11n and 802.11ac. 802.11af supports 5 MHz, 10 MHz, and 20 MHz bandwidths in the TV White Space (TVWS) spectrum, 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 macro coverage areas. MTC devices may have limited capabilities, including, for example, support for (e.g., support only for) specific and / or limited bandwidths. MTC devices may include batteries with above-threshold battery life (e.g., to maintain very long battery life).

[0043] WLAN systems that may support multiple channels and channel bandwidths, such as 802.11n, 802.11ac, 802.11af, and 802.11ah, include a channel that may be designated as a primary channel. The primary channel may have a bandwidth equal to the maximum common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel may be configured and / or limited by the STAs among all STAs operating in the BSS that support the smallest bandwidth operating mode. In an 802.11ah example, the primary channel may be 1 MHz wide for STAs (e.g., MTC type devices) that support (e.g., only) the 1 MHz mode, even if the AP and other STAs in the BSS support 2 MHz, 4 MHz, 8 MHz, 16 MHz, and / or other channel bandwidth operating modes. Carrier sensing and / or Network Allocation Vector (NAV) settings may depend on the state of the primary channel. For example, if the primary channel is busy due to a STA (that only supports 1 MHz mode of operation) transmitting to the AP, the entire available frequency band may be considered busy even though most of the frequency band may remain idle and available for use.

[0044] In the United States, the available frequency bands that can be used by 802.11ah are 902MHz to 928MHz. In South Korea, the available frequency bands are 917.5MHz to 923.5MHz. In Japan, the available frequency bands are 916.5MHz to 927.5MHz. The total bandwidth available for 802.11ah is 6MHz to 26MHz depending on the country code.

[0045] FIG. 1D is a system diagram illustrating the RAN 113 and the CN 115 according to one embodiment. As mentioned above, the RAN 113 may communicate with the WTRUs 102a, 102b, 102c over the air interface 116 using NR radio technology. The RAN 113 may also communicate with the CN 115.

[0046] The RAN 113 may include gNBs 180a, 180b, 180c, although it will be understood that the RAN 113 may include any number of gNBs while remaining consistent with an embodiment. The gNBs 180a, 180b, 180c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In an embodiment, the gNBs 180a, 180b, 180c may implement MIMO technology. For example, the gNBs 180a, 108b may utilize beamforming to transmit and / or receive signals to the gNBs 180a, 180b, 180c. Thus, the gNB 180a may transmit wireless signals to and / or receive wireless signals from the WTRU 102a, for example, using multiple antennas. In one embodiment, the gNBs 180a, 180b, 180c may implement carrier aggregation technology. For example, the gNB 180a may transmit multiple component carriers to the WTRU 102a (not shown). A subset of these component carriers may be on an unlicensed spectrum, and the remaining component carriers may be on a licensed spectrum. In one embodiment, the gNBs 180a, 180b, 180c may implement Coordinated Multi-Point (CoMP) technology. For example, the WTRU 102a may receive coordinated transmissions from the gNBs 180a and 180b (and / or gNB 180c).

[0047] The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using transmissions associated with a scalable numerology. For example, the OFDM symbol spacing and / or OFDM subcarrier spacing may vary for different transmissions, different cells, and / or different portions of the wireless transmission spectrum. The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using subframes or transmission time intervals (TTIs) of different or scalable lengths (e.g., including different numbers of OFDM symbols and / or lasting different lengths of absolute time).

[0048] The gNBs 180a, 180b, 180c may be configured to communicate with the WTRUs 102a, 102b, 102c in a standalone configuration and / or a non-standalone configuration. In a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c without accessing another RAN (e.g., eNode-Bs 160a, 160b, 160c, etc.). In a standalone configuration, the WTRUs 102a, 102b, 102c may utilize one or more of the gNBs 180a, 180b, 180c as mobility anchor points. In a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using signals in unlicensed bands. In a non-standalone configuration, the WTRUs 102a, 102b, 102c may communicate with and connect to a gNB 180a, 180b, 180c while also communicating with and connecting to another RAN, such as an eNode-B 160a, 160b, 160c. For example, the WTRUs 102a, 102b, 102c may implement DC principles to communicate with one or more gNBs 180a, 180b, 180c and one or more eNode-Bs 160a, 160b, 160c substantially simultaneously. In a non-standalone configuration, the eNode-Bs 160a, 160b, 160c may act as mobility anchors for the WTRUs 102a, 102b, 102c, while the gNBs 180a, 180b, 180c may provide additional coverage and / or throughput for serving the WTRUs 102a, 102b, 102c.

[0049] Each of the gNBs 180a, 180b, 180c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the UL and / or DL, support for network slicing, dual connectivity, interworking between NR and E-UTRA, routing of user plane data to User Plane Functions (UPFs) 184a, 184b, routing of control plane information to Access and Mobility Management Functions (AMFs) 182a, 182b, etc. As shown in FIG. 1D, the gNBs 180a, 180b, 180c may communicate with each other via an Xn interface.

[0050] 1D may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one Session Management Function (SMF) 183a, 183b, and possibly a Data Network (DN) 185a, 185b. Although each of the foregoing elements is shown as part of the CN 115, it will be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0051] The AMF 182a, 182b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via an N2 interface and may function as a control node. For example, the AMF 182a, 182b may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, supporting network slicing (e.g., handling different PDU sessions with different requirements), selecting a particular SMF 183a, 183b, managing registration areas, terminating NAS signaling, mobility management, etc. The network slicing may be used by the AMF 182a, 182b to customize the CN support of the WTRUs 102a, 102b, 102c based on the type of service utilizing the WTRUs 102a, 102b, 102c. For example, different network slices may be established for different use cases, such as services relying on ultra-reliable low latency (URLLC) access, services relying on enhanced massive mobile broadband (eMBB) access, services for machine type communication (MTC) access, and / or the like. The AMF 162 may provide a control plane function for switching between the RAN 113 and other RANs (not shown) that employ other radio technologies, such as LTE, LTE-A, LTE-A Pro, and / or non-3GPP access technologies such as WiFi.

[0052] The SMFs 183a, 183b may be connected to the AMFs 182a, 182b in the CN 115 via an N11 interface. The SMFs 183a, 183b may also be connected to the UPFs 184a, 184b in the CN 115 via an N4 interface. The SMFs 183a, 183b may select and control the UPFs 184a, 184b and configure the routing of traffic through the UPFs 184a, 184b. The SMFs 183a, 183b may perform other functions such as managing and assigning WTRU IP addresses, managing PDU sessions, controlling policy enforcement and QoS, providing downlink data notification, etc. The PDU session type may be IP-based, non-IP-based, Ethernet-based, etc.

[0053] The UPFs 184a, 184b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via an N3 interface, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices. The UPFs 184, 184b may perform other functions, such as routing and forwarding packets, enforcing user plane policies, supporting multi-homed PDU sessions, handling user plane QoS, buffering downlink packets, providing mobility anchoring, etc.

[0054] The CN 115 may facilitate communication with other networks. For example, the CN 115 may include or communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that serves as an interface between the CN 115 and the PSTN 108. Additionally, the CN 115 may provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers. In an embodiment, the WTRUs 102a, 102b, 102c may be connected to local Data Networks (DNs) 185a, 185b through the UPFs 184a, 184b via an N3 interface to the UPFs 184a, 184b and an N6 interface between the UPFs 184a, 184b and the DNs 185a, 185b.

[0055] 1A-1D and the corresponding description thereof, one or more or all of the functions described herein with respect to one or more of the WTRUs 102a-d, base stations 114a-b, eNode-Bs 160a-c, MME 162, SGW 164, PGW 166, gNBs 180a-c, AMFs 182a-b, UPFs 184a-b, SMFs 183a-b, DNs 185a-b, and / or any other devices described herein may be performed by one or more emulation devices (not shown). The emulation devices may be one or more devices configured to emulate one or more or all of the functions described herein. For example, the emulation devices may be used to test other devices and / or to simulate network and / or WTRU functions.

[0056] The emulation devices may be designed to implement one or more tests of other devices in a lab environment and / or an operator network environment. For example, one or more emulation devices may perform one or more or all functions while fully or partially implemented and / or deployed as part of a wired and / or wireless communication network to test other devices in the communication network. One or more emulation devices may perform one or more or all functions while temporarily implemented / deployed as part of a wired and / or wireless communication network. The emulation devices may be directly coupled to another device for testing purposes and / or may perform testing using terrestrial wireless communication.

[0057] The one or more emulation devices may perform one or more functions, including but not limited to, while not implemented / deployed as part of a wired and / or wireless communication network. For example, the emulation devices may be utilized in test scenarios in a test lab and / or in an undeployed (e.g., test) wired and / or wireless communication network to implement testing of one or more components. The one or more emulation devices may be test equipment. Direct RF coupling and / or wireless communication via RF circuitry (which may include, for example, one or more antennas) may be used by the emulation devices to transmit and / or receive data.

[0058] (Detailed Description) For vehicular communications (V2X), various modes of operation may exist, such as (e.g., LTE) Release 14 (R14) Modes 3 and 4, and Release 16 (R16) Mode 2. For Mode 2 operation, the R16 V2X WTRU performs resource (re)selection based on sensing, for example, without any central scheduling and inter-WTRU coordination. In such a case, the sensing mechanism may result in (e.g., potential) collisions when available resources are limited (e.g., especially in congested scenarios), for example, due to an increase in the RSRP threshold. Furthermore, in such a case, if (e.g., such) collisions occur for semi-persistent resource reservations, the collisions may become persistent and cause continuous packet losses. As a result, the R16 NR sidelink (SL) does not (e.g., cannot) ensure reliable low latency, for example, under conditions when the channel is busy (e.g., in congested scenarios).

[0059] Release 17 (R17) supports Ultra Reliable Low Latency Communications (URLLC) type SL use cases in (e.g., Advanced) operating scenarios. Considering R16 providing limited support for certain transmissions (e.g., as described above), inter-WTRU cooperation in Mode 2 operation is considered, e.g., for R17. That is, for R17, inter-UE cooperation to improve reliability and latency of SL transmissions is considered. One form of such cooperation is a WTRU providing assistance information to another WTRU. The assistance information can be a set of resources determined by the WTRU. For example, inter-WTRU cooperation involves a first WTRU determining a set of resources in Mode 2 and transmitting them to a second WTRU, so that the second WTRU can take this into account in its resource selection for its transmission.

[0060] However, in the case of Mode 2 (e.g., conventionally, in the related art, such as in R17), there is a lack of coordination between WTRUs (e.g., no coordination), e.g., one WTRU does not know if or when another WTRU has traffic for transmission, and further, one WTRU does not know what type of resources another WTRU uses. Such lack of coordination may result in an excessive number of required transmissions. Thus, there is a need to enable inter-WTRU coordination features while avoiding an excessive number of required transmissions. Taking into account at least the above-mentioned problems (e.g., lack of inter-WTRU coordination), there is a need to provide (e.g., address, resolve, etc.) solutions to any of the following problems / questions: (1) which WTRU(s) provide assistance information; (2) which WTRU(s) request and / or receive assistance information; (3) what are the trigger conditions for such coordination; (4) how a WTRU(s) obtains assistance information that is useful, for example, for resource selection of another WTRU(s); (5) what the assistance information includes; (6) how the assistance information is transmitted; and (7) how another WTRU(s) uses the assistance information in its resource selection.

[0061] According to an embodiment, the WTRU may transmit assistance information (e.g., perform an assisting transmission), e.g., to another WTRU, or any other similar and / or suitable network node. According to an embodiment, the WTRU may perform an assisting transmission, e.g., to assist SL resource selection for transmission by another WTRU. According to an embodiment, the assisting transmission may carry information including a set of SL resources (e.g., including assistance). According to an embodiment, the WTRU may be an assisting WTRU (e.g., an assisting WTRU). That is, as discussed and / or referenced herein, a WTRU may be referred to as an assisting WTRU, e.g., when it performs an assisting transmission. According to an embodiment, the WTRU(s) may either trigger or receive an assisting transmission. According to an embodiment, the WTRU(s) that trigger and / or receive an assisting transmission may be referred to as an aided WTRU. According to an embodiment, the assisting WTRU and the aided WTRU may be referred to as such herein with respect to a (e.g., particular) assistance information transmission.

[0062] WTRU Determination of Trigger for Assisted Transmission According to an embodiment, a WTRU may determine to either perform an assisting transmission and become a supporting WTRU. According to an embodiment, a WTRU may determine to perform an assisting transmission and / or become a supporting WTRU according to (e.g., based on) any number of conditions (e.g., triggers). According to an embodiment, such triggers and / or conditions (e.g., used to determine whether to perform an assisting transmission and / or become a supporting WTRU) may include: (1) the WTRU receives an explicit request for an assisting transmission, e.g., from an assisted WTRU; (2) the WTRU receives a semi-persistent resource reservation by the assisted WTRU; (3) the WTRU receives a CSI request from the assisted WTRU; (4) the WTRU detects (e.g., some) collisions applicable to semi-persistent resource reservation, e.g., by / with the assisted WTRU; (5) the WTRU is unable to decode some PSSCH from the assisted WTRU and detects a corresponding HARQ (6) the WTRU is unable to decode some PSSCHs corresponding to resource reservations from the supported WTRU; (7) the WTRU is located within a range below (e.g., extending beyond) a threshold (as referred to in this specification, the terms configured, pre-configured, and (pre-)configured are used interchangeably) from the supported WTRU; (8) the WTRU measures (e.g., detects, determines, etc.) a congestion metric (e.g., Channel Busy Ratio (CBR)) higher than a (pre-)configured threshold; (9) the WTRU receives a configuration for assistance transmission during (e.g., during) SL link establishment (e.g., procedure) signaling applicable to the supported WTRU; (10) the WTRU is of a (e.g., (pre-)configured, specific, etc.) type (e.g., vehicular WTRU, pedestrian user, vulnerable road user (VRU), first responder, etc.). According to an embodiment, the WTRU may trigger (eg, determine to perform, execute, transmit, etc.) an assisting transmission, for example, when data associated with the supported WTRU is available (eg, for transmission).According to an embodiment, a WTRU may be configured (eg, pre-configured) to perform, for example, periodic assistance transmissions for, for example, any of a V2X application, a data group, a WTRU group, an application group, and the like.

[0063] FIG. 2 is a diagram illustrating assistance information transmission triggered by an explicit request according to an embodiment.

[0064] According to embodiments, the transmission of assistance information (e.g., WTRU-assisted transmission) may be triggered by a request (e.g., explicit, signaled, determined, etc.). According to embodiments, the transmission of a (e.g., such, explicit, signaled, determined, etc.) request for assistance transmission (e.g., an assistance transmission request) may be performed (e.g., triggered, determined, etc.) according to, for example, a (e.g., specific) condition. According to embodiments, the WTRU may determine to either send an explicit assistance transmission request or become an assisted WTRU, for example, when transmission block (TB) resource (re)selection is triggered by higher layers.

[0065] According to an embodiment, the WTRU determines to either send an explicit assistance transmission request (e.g., in addition to and / or instead of TB resource (re)selection triggered by higher layers) and become a assisted WTRU according to (e.g., based on, meeting, etc.) any of the following conditions (e.g., triggers): (1) the (e.g., remaining) packet delay budget exceeds a (pre-)configured threshold (e.g., the remaining packet delay budget allows for round trip propagation and WTRU processing time associated with (e.g., caused by) the assistance transmission request and the assistance transmission; (2) the WTRU determines whether the assisted transmission request is within the range of (e.g., 100% confidence interval (CI)); (3) the assisted transmission request is within the range of (e.g., 100% confidence interval (CI)); (4) the assisted transmission request is within the range of (e.g., 100% confidence interval (CI)); (5) the assisted transmission request is within the range of (e.g., 100% confidence interval (CI)); (6) the assisted transmission request is within the range of (e.g., 100% confidence interval (CI)); (7) the assisted transmission request is within the range of (e.g., 100% confidence interval (CI)); (8) the assisted transmission request is within the range of (e.g., 100% confidence interval (CI)); (9) the assisted transmission request is within the range of (e.g., 100% confidence interval (CI)); (100% confidence interval (CI)). (3) the priority exceeds a (pre-)configured threshold (e.g., an assistance transmission may be triggered by the transmission of a high-priority TB, such as a BLER of 1E-5); (4) the size of the transport packet exceeds a (pre-)configured threshold (e.g., an assistance transmission may be triggered by the transmission of a large TB requiring a large number of subchannels); (5) the distance to the WTRU from which the assistance transmission request is sent (e.g., the distance to the intended) WTRU falls below a (pre-)configured threshold.

[0066] According to an embodiment, the content of the assistance transmission request may indicate various information. According to an embodiment, the supported WTRU may include, for example, in the assistance transmission request, any of the following (e.g., resource (re)selection) information: (1) e.g., a resource pool from which the PSSCH resource may be reported; (2) e.g., an L1 priority of the TB used for transmission by the supported WTRU; (3) e.g., a remaining packet delay budget (PDB) (i.e., in slots) of the TB used for transmission by the supported WTRU; (4) T1_TB, e.g., the start of a transmission window in which the TB may be transmitted; (5) T2_TB, e.g., the end of a transmission window, (6) e.g., the number of subchannels to be used for PSSCH transmission of the TB; and (7) the number of required (requested) resources in the resource set, such as (i) the number of requested resources in the resource set, and (ii) a ratio of the total number of candidate resources in the transmission window.

[0067] According to an embodiment, the (e.g., assisted) WTRU may determine, for example, the (e.g., remaining) PDB included in the assisting transmission request according to (e.g., based on) either the remaining PDB of the TB used for transmission, the time resources reserved for the assisting transmission request. According to an embodiment, the WTRU may calculate the remaining PDB included in the assisting transmission request as shown in the following equation [1]:

[0068]

number

[0069] According to an embodiment, for example, if the WTRU receives a resource selection trigger in slot n associated with TB and determines that the WTRU transmits an assistance transmission request in slot m, the WTRU may calculate the remaining PDB using equation [1]. According to an embodiment, the assisted WTRU (e.g., in another case) may determine T2_TB based on a (pre-)configured T2_min. For example, according to an embodiment, T2_min≦T2_TB≦PDB TB If T2_min>PDB, then the supported WTRU may select T2_TB, for example, according to the WTRU implementation (e.g., designed, selected, etc.). TB Then, T2_DB is a PDB. TB may be equal to

[0070] According to an embodiment, the supported WTRU may determine T1_TB according to (e.g., based on) the QoS requirement of the TB. That is, according to an embodiment, the supported WTRU may determine an initial T1_TB for a large transmission window, e.g., to allow more resources for resource selection of a TB having either high reliability and / or priority requirement. According to an embodiment, either T1_TB and T2_TB may be any of absolute frame, subframe, and slot numbers. According to an embodiment, either T1_TB and T2_TB may be an offset (i.e., number of slots) relative to the timing (slot) of the assistance transmission request.

[0071] According to embodiments, the assistance transmission request may be transmitted using any of a variety of resources, signaling, messaging, channels, etc. According to embodiments, the assistance transmission request may be transmitted (e.g., carried) using PHY signaling, e.g., using a PSCCH. According to embodiments, the assistance transmission request may be transmitted (e.g., carried) using a standalone PSCCH. According to embodiments, the assistance transmission request may be transmitted (e.g., carried) using either MAC CE or RRC signaling, e.g., using a PSSCH transmission.

[0072] According to an embodiment, the supported WTRU may transmit the assistance transmission request according to any of a number of configurations. For example, according to an embodiment, the supported WTRU may transmit the assistance transmission request according to a configuration having a PSSCH / PSCCH using one subchannel, e.g., if the supported WTRU transmits (e.g., may transmit) a PSSCH that includes only an assistance transmission request. As another example, according to an embodiment, the supported WTRU may transmit the assistance transmission request according to a configuration having a PSSCH / PSCCH using multiple subchannels, e.g., if the supported WTRU transmits a PSSCH that includes both an assistance transmission request and a data TB.

[0073] According to an embodiment, the assisted WTRU may perform sensing, for example, for resource selection for the assisting transmission request. According to an embodiment, the WTRU may apply any of various sensing patterns, for example, as discussed below. According to an embodiment, the sensing parameter may be, for example, a resource pool from which resources are reported. That is, according to an embodiment, the assisted WTRU may select resources from a resource pool dedicated / for the assisting transmission request. According to an embodiment, the sensing parameter may be L1 priority. That is, according to an embodiment, the L1 priority of the assisting transmission request may be (pre-) configured, for example, such that the L1 priority is set to the highest / lowest priority. According to an embodiment, the L1 priority of the assisting transmission request may be the same as that of the TB carried in the same transmission (e.g., may be set as ). According to an embodiment, the sensing parameter may be the remaining PDB. That is, according to an embodiment, the remaining PDB of the assisting transmission request may be (pre-) configured. For example, either a fixed value or a small value may be (pre-) configured. According to an embodiment, the remaining PDB of the assisting transmission request may be the same as that of the TB carried in the same transmission (e.g., may be set as ). According to an embodiment, the sensed parameter may be, for example, the number of sub-channels to be used for the request for assistance transmission.

[0074] According to an embodiment, the assisted WTRU may determine one of the T1_request and the T2_request of the assisting transmission request. According to an embodiment, the T1_request may be determined according to (e.g., based on) the WTRU processing. According to an embodiment, the T2_request may be determined according to (e.g., based on) a (pre-)configuration. For example, according to an embodiment, a fixed T2_request may be (pre-)configured for the assisting transmission request. According to an embodiment, the T2_request may be determined according to (e.g., based on) the remaining PDB of the TB. That is, according to an embodiment, the assisted WTRU may select the T2_request to ensure that any of the following steps can be completed within the remaining PDB: transmitting / transmitting the assisting transmission request; receiving the assisting transmission; processing the assistance information and selecting resources for the transmission of the TB; and transmitting / transmitting the TB.

[0075] According to an embodiment, the assistance request transmission may be (e.g., different from the one described above) a new (e.g., different) SL physical signal and / or physical channel (e.g., transmitted, sent, etc., via, using, by the WTRU contained therein). That is, according to an embodiment, the WTRU may transmit the assistance request (e.g., transmission) on a new SL PHY signal and / or PHY channel. According to an embodiment, the WTRU may be configured (e.g., pre-configured) with a resource allocation, e.g., for either (dedicated, only, etc.) the assistance request and the assistance information transmission. According to an embodiment, the resource allocation may be either (1) a resource pool, and (2) a set of, e.g., time and frequency resources allocated within the resource pool.

[0076] According to embodiments, such resources may be configured (e.g., pre-configured) for either assistance request transmissions and assistance information transmissions (e.g., as described above). According to embodiments, such resources may not be used by / for other SL transmissions (e.g., V2X data transmissions). According to embodiments, such time and frequency resources (e.g., set) may include (e.g., consist of, comprise, etc.) any of a set of SL slots, a set of SL symbols, a set of subchannels, a set of PRBs, and a set of subcarriers. According to embodiments, such time and frequency resources (e.g., set) may be configured (e.g., pre-configured) in / for a resource pool for SL data transmissions.

[0077] According to an embodiment, the WTRU may determine resources for the help request transmission. According to an embodiment, the WTRU may determine (e.g., select, pre-configure, etc.) resources, such as any time and frequency resources of the PHY help request channel and ZC sequence index, according to any of the following: (1) source ID and / or destination ID of the SL link for which the help request is intended; (2) link ID of the SL link for which the help request is intended; (3) total number of time and frequency resources configured (e.g., pre-configured) for the help request transmission; (4) total number of ZC sequences configured (e.g., pre-configured) for the help request transmission; and (5) index / number of slots for the request transmission. According to an embodiment, there may be cases where the WTRU may trigger the help request transmission according to (e.g., based on) a trigger condition (e.g., as described above). According to an embodiment, in such a case, the WTRU may select the earliest (e.g., immediately following) SL slot after the trigger, such as, for example, an SL slot for which resources for the help request transmission are pre-configured. According to an embodiment, the resources available for sending a request for assistance (e.g., resources that are available) may be indexed according to, for example, the total number of configured (e.g., preconfigured) ZC sequences and frequency resources (e.g., PRBs). According to an embodiment, each resource may be any of the ZC sequences and frequency resources (e.g., PRBs).

[0078] According to an embodiment, the index of the requested transmission resource may increase after a configured (e.g., pre-configured) ZC sequence set in a PRB and may further increase (e.g., for each, each, etc., thereafter) for a configured (e.g., pre-configured) PRB. According to an embodiment, for example, with six configured (e.g., pre-configured) ZC sequences, the resources for assistance request transmission may be indexed from 0 to 5 in a first configured (e.g., pre-configured) PRB and from 6 to 11 in a second PRB. That is, for example, the index may increase by 6 in each PRB until the last configured (e.g., pre-configured) PRB. According to an embodiment, such indexing may provide, for example, an index of each available resource that the WTRU selects for assistance request transmission. According to an embodiment, the WTRU may determine any number of such resources according to (e.g., based on) any of the following: a WTRU ID and / or a link ID, an index of an SL slot, and a total number of resources. For example, the WTRU may select an index according to a modular function using the source ID (eg, in decimal format) and the total number(s) of indexed resources.

[0079] FIG. 3 illustrates assistance information transmission triggered by semi-persistent (SP) based resource reservation according to an embodiment.

[0080] According to an embodiment, the WTRU may perform an assisting transmission triggered by the received SP resource reservation. According to an embodiment, the WTRU may determine whether to perform an assisting transmission or to become a assisting WTRU, for example, when the WTRU receives a data transmission with the SP resource reservation. According to an embodiment, the WTRU may determine that the data (e.g., the received data transmission) may be intended for itself and may continue to receive the data according to (e.g., based on) any of the identifiers (IDs), such as the destination ID, the source ID, and the group member ID. According to an embodiment, the destination ID may be carried in the second SCI and may indicate a broadcast link to which the WTRU may be subscribed. According to an embodiment, any of the source ID and the destination ID may be carried in the second SCI and may indicate a unicast link that the WTRU may have established. According to an embodiment, in the case of the group member ID, the destination ID carried in the second SCI may indicate a groupcast link to which the WTRU may be subscribed.

[0081] According to an embodiment, the helping WTRU may trigger an assisting transmission for any (e.g., each) reservation period. According to an embodiment, the helping WTRU may not trigger an assisting transmission after slot n. According to an embodiment, the helping WTRU may not trigger an assisting transmission after slot n based on any of the following: the start of the transmission window associated with the reserved transmission TxWindow_start; T2 of the helping transmission; and a (pre-)configured offset between the start of the transmission window and T2 of the helping transmission Toffset. For example, slot n may not be the slot corresponding to a timing of TxWindow_start-Toffset-T2. According to an embodiment, the result (e.g., the objective) of such a case may be to allow sufficient time for the helped WTRU to receive the assisting transmission and process the received resource set to select a resource for the reserved transmission.

[0082] According to an embodiment, the WTRU assistance transmission may be triggered by a received CSI request transmission. That is, according to an embodiment, the WTRU may determine to perform an assistance transmission, e.g., become a helping WTRU, when the WTRU receives a CSI request transmission. According to an embodiment, the WTRU may provide (e.g., transmit) assistance information and a CSI report in one transmission.

[0083] According to an embodiment, a WTRU-assisted transmission may be triggered by detection of a collision of received SP resource reservations. According to an embodiment, a WTRU may determine to perform an assisted transmission and become a helping WTRU, for example, if the WTRU detects a collision set for the received SP resource reservations. According to an embodiment, a WTRU may detect a collision specific to a resource reservation already received from another WTRU, which may be referred to as a standing reservation. That is, according to an embodiment, a WTRU may detect a collision specific to a received resource reservation if the WTRU identifies an overlapping resource reservation from a different WTRU(s) having a higher L1 priority. According to an embodiment, a WTRU may detect a collision specific to a resource reservation if the WTRU measures an RSRP associated with any resource reservation from another WTRU that is greater than a corresponding RSRP threshold. According to an embodiment, the WTRU may determine the corresponding RSRP threshold according to any of the following: (1) RSRP(s) value(s) in a transmission received within a resource received in a (e.g., previous) reservation period, such as the RSRP value of the latest received transmission, the RSRP value averaged over several recently received transmissions, and the maximum RSRP value over several recently received transmissions; (2) a (pre-)configured offset of X dB (e.g., 0 dB or 3 dB); (3) L1 priority of standing reservation (P1), (4) L1 priority of overlapping reservation (P2).

[0084] According to an embodiment, the corresponding RSRP threshold may be the sum of the RSRP value and an offset. According to an embodiment, the corresponding RSRP threshold may be, for example, a weighted RSRP value based on the RSRP value. According to an embodiment, the weighting factor may be, for example, based on the L1 priorities of both overlapping resource reservations (e.g., using a (pre)configured function (P1, P2)).

[0085] According to an embodiment, the WTRU may determine to perform an assisting transmission and become a helping WTRU if the detected collision exceeds a (pre-)configured threshold (e.g., 1, 5, 10, etc.). According to an embodiment, the WTRU may, for example, maintain a counter for consecutive collisions within a (pre-)configured period and / or up to a threshold. According to an embodiment, consecutive collisions may indicate that a collision event may be occurring during a consecutive period of standing resource reservation. According to an embodiment, the result (e.g., objective) when detecting a collision may be to identify a persistent collision event and (e.g., subsequently) initiate resource reselection, for example, by transmitting an assisting resource set to avoid future collisions.

[0086] According to embodiments, there may be cases where the WTRU may decode any of the first state SCI and the second tier SCI of the PSSCH transmission, e.g., at the transmission instance(s) of the received SP-based resource reservation(s). According to embodiments, in such cases, the WTRU may determine a collision according to (based on) any of: (1) the resources reserved in the first tier SCI, (2) the WTRU type indication in the first tier SCI, and (3) the source ID and / or destination (e.g., destination ID) of the second tier SCI. According to embodiments, the WTRU may determine a collision if any (e.g., number) of the decoded information listed above is not equal to the corresponding parameter of the received SP-based reservation of resources.

[0087] FIG. 4 illustrates an assisted transmission triggered by either a HARQ ACK / NACK transmission and a HARQ retransmission, according to an embodiment.

[0088] According to an embodiment, the WTRU assisted transmission may be triggered by a HARQ NACK transmission, e.g., with reference to FIG. 4. According to an embodiment, the WTRU may determine to perform an assisted transmission and to determine to perform transmission assistance and become a helping WTRU if the number of HARQ NACK transmissions corresponding to the resource reservation exceeds a (pre-)configured threshold. According to an embodiment, the WTRU may determine to perform an assisted transmission and become a helping WTRU if the number of HARQ retransmission events reaches a (pre-)configured maximum number and / or exceeds a (pre-)configured threshold. According to an embodiment, the WTRU may select a threshold from among, e.g., any number of (pre-)configured) thresholds.

[0089] According to an embodiment, the WTRU may select the threshold according to a fixed value (e.g., resource pool specific (pre)configured). According to an embodiment, the value may be equal to a (pre)configured maximum number of HARQ retransmissions per resource pool. According to an embodiment, the WTRU may select the threshold according to (e.g., based on) the QoS (e.g., a low threshold corresponding to high reliability and / or low latency). According to an embodiment, the WTRU may select the threshold according to (e.g., based on) the CBR (e.g., a low threshold if the CBR is high). According to an embodiment, the WTRU may select the threshold according to (e.g., based on) the RSRP of the received PSCCH transmission (e.g., a low threshold if the PSCCH RSRP is below a (pre)configured threshold). According to an embodiment, the WTRU may select the threshold according to (e.g., based on) the CSI of the received PSSCH transmission (e.g., a low threshold if the CQI applicable to the subchannel(s) of the received PSSCH transmission is below a (pre)configured threshold). According to an embodiment, the WTRU may select a threshold value according to (eg, based on) the WTRU speed (eg, mobility state) (eg, a low threshold value when the WTRU speed is high and the channel is changing rapidly).

[0090] According to an embodiment, dynamic threshold selection may allow the WTRU to perform more frequent assistance transmissions, for example, when channel conditions deteriorate. According to an embodiment, the WTRU may count HARQ NACK transmissions for all initial and retransmissions. According to an embodiment, in such a case, there may be multiple HARQ NACK transmissions for each reservation interval. According to an embodiment, the WTRU may count one HARQ NACK for each reservation period (e.g., the NACK corresponding to the final HARQ retransmission). According to an embodiment, if the WTRU determines that the number of HARQ retransmissions has reached or exceeded a (pre)configured maximum number, the WTRU may include the event occurring over successive periods of resource reservation.

[0091] According to an embodiment, a WTRU-assisted transmission may be triggered according to (e.g., based on) failure to receive any number of TBs. According to an embodiment, the WTRU may determine to perform an assisted transmission and become a helping WTRU if the number of TBs that the WTRU is unable to receive exceeds a (pre-)configured threshold. According to an embodiment, for example, if HARQ is disabled, the WTRU may determine according to the number of TBs that the WTRU is unable to receive over a continuous period of resource reservation compared to a (e.g., (pre-)configured) threshold. According to an embodiment, the WTRU may select the threshold according to any of the following: (1) a fixed value (e.g., a (pre)configured value specific to a resource pool); (2) QoS (e.g., a low threshold corresponding to high reliability and / or low latency); (3) CBR (e.g., a low threshold if the CBR is high); (4) RSRP of the received PSCCH transmission (e.g., a low threshold if the PSCCH RSRP is below a (pre)configured threshold); (5) CSI of the received PSSCH transmission (e.g., a low threshold if the CQI applicable to a subchannel of the received PSSCH transmission is below a (pre)configured threshold); (6) WTRU speed (mobility, movement state, etc.) (e.g., a low threshold if the WTRU speed is high and the channel is changing rapidly).

[0092] According to an embodiment, a WTRU assistance transmission may be triggered according to a range (e.g., distance, value, location, etc.). According to an embodiment, a WTRU may determine to perform an assistance transmission and become a helping WTRU if the WTRU is located within a (pre-)configured) range, e.g., between itself and an aided WTRU. According to an embodiment, a WTRU may determine to perform an assistance transmission and become a helping WTRU if the WTRU receives a semi-persistent resource reservation from an aided WTRU. According to an embodiment, the range may be determined according to either a minimum communication range requirement or a (pre-)configured threshold. For example, a WTRU may determine to perform an assistance transmission and become a helping WTRU if the WTRU moves within a range of MCR-X meters (where X may be a (pre-)configured threshold).

[0093] According to an embodiment, a WTRU-assisted transmission may be triggered by a CBR. According to an embodiment, a WTRU may perform an assisting transmission and determine to become a supporting WTRU if either (1) the WTRU measures a CBR higher than a (pre-)configured threshold or (2) the WTRU receives a semi-persistent resource reservation from a supported WTRU.

[0094] According to an embodiment, the WTRU-assisted transmission may be performed (e.g., triggered) according to (e.g., based on, etc.) a configuration. According to an embodiment, the WTRU may determine to perform an assisted transmission and become a helping WTRU if the WTRU receives a configuration for an assisted transmission. According to an embodiment, for example, the WTRU may receive a configuration for an assisted transmission during link establishment of a unicast link. According to an embodiment, the assisting transmission configuration may include information (e.g., used, indicating, etc.) for determining an opportunity for / of an assisting transmission (e.g., a periodicity of transmissions and / or traffic / transmission patterns of associated services).

[0095] According to an embodiment, a WTRU-assisted transmission may be performed (e.g., triggered) according to a WTRU type. According to an embodiment, a WTRU may determine to perform an assistance transmission and become a helping WTRU if any of the following occurs: (1) the WTRU is of a (e.g., unique, specific, (pre-)configured) type of WTRU (e.g., pedestrian or VRU type); (2) the WTRU receives an SP resource reservation from a helped WTRU. According to an embodiment, the WTRU may have a (pre-)configuration for an assistance transmission.

[0096] According to an embodiment, the WTRU may determine to perform an assistance transmission and become a assisting WTRU in any / all of the following cases: (1) the WTRU is of a (pre-)configured type (e.g., a vehicular WTRU, i.e., a V2X device installed in a vehicle); (2) the WTRU may be configured by higher layers to perform periodic assistance transmission(s); (3) the measured CBR exceeds a (pre-)configured threshold.

[0097] According to an embodiment, the WTRU-assisted transmission may be performed according to (e.g., triggered, based on, etc.) an indication of a change in resource reservation. According to an embodiment, the WTRU may determine to perform an assisted transmission and become a supporting WTRU if the WTRU receives an indication of a change (e.g., implicit, explicit, etc.) in resource reservation of the (e.g., one, any number, etc.) SL process(es) from the supported WTRU. According to an embodiment, the supported WTRU may perform (e.g., should perform) resource (re)selection of (e.g., one, any number, etc.) SL process(es) according to either: (1) a resource (re)selection counter of a sidelink process reaches zero; or (2) the WTRU's traffic pattern is changed, including any change in periodicity, offset, TB size, and packet size. For example, the supported WTRU may have one resource set semi-persistently reserved for one sidelink process. According to an embodiment, in such a case, the supporting WTRU may trigger a supporting transmission when (e.g., any number of) transmissions in the reserved resources do not indicate further semi-persistent reservations for the resource set. According to an embodiment, such an indication (e.g., of information contained in the transmissions in the reserved resources) may be conveyed using either the SCI, MAC CE, or RRC.

[0098] According to an embodiment, a WTRU-assisted transmission may be performed (e.g., triggered) if data associated with the supported WTRU is available. According to an embodiment, the supporting WTRU may, for example, trigger an assistance transmission to one supported WTRU if (e.g., only if) data associated with the supported WTRU is available. In such a case, the WTRU may not build a TB that includes only assistance information.

[0099] According to embodiments, for example, a periodic assistance transmission transmitted by a WTRU may be configured (e.g., associated) with any of an application (e.g., a group of applications, a V2X application, etc.), a WTRU group, and a data group. According to embodiments, a WTRU may be (pre) configured to perform periodic assistance transmissions. According to embodiments, a periodic assistance transmission may be either (1) a semi-persistent broadcast transmission, or (2) a groupcast transmission, for example, for any of an associated V2X application, a V2X data group, a V2X WTRU group, etc. According to embodiments, a vehicular WTRU (VWTRU) may be (pre) configured by higher layers to perform (e.g., transmit, transmit, etc.) a periodic assistance transmission that provides (e.g., by including information indicating) available resource information. According to embodiments, a periodic assistance transmission may be transmitted (e.g., provided, transmitted, guided, etc.) by the VWTRU to any number of V2X WTRUs in proximity (e.g., to the VWTRU). According to embodiments, a proximate (e.g., V2X) WTRU (e.g., to a VWTRU) may be and / or may include any of the WTRUs discussed below, however, the disclosure is not limited thereto and any type of WTRU suitable for the operations and features described herein may be a proximate WTRU to a VWTRU.

[0100] According to an embodiment, the neighboring WTRU may be, for example, either a PWTRU or a VRU transitioning from an inactive / sleep state to an active / awake state to initiate SL transmission. If such a PWTRU / VRU does not need to perform sensing during the inactive / sleep period, it may not have the information required (e.g., used, required, etc.) for resource selection for SL transmission in the active / awake state. According to an embodiment, for example, in such a case, either the PWTRU and the VRU may perform resource selection according to (e.g., based on) received assisting resource information, i.e., until sensing information is available.

[0101] According to an embodiment, the neighboring WTRU may be either a PWTRU or a VRU (e.g., a device) having (e.g., with) a battery constraint (e.g., low available battery amount, high battery energy consumption rate, etc.). According to an embodiment, either the PWTRU or the VRU device may be (pre-) configured to not perform sensing, e.g., when the battery level is below a (pre-) configured threshold. According to an embodiment, in such a case, either the PWTRU or the VRU may perform resource selection for SL transmission, e.g., according to (e.g., based on) the (e.g., received) assisting resource information. According to an embodiment, the neighboring WTRU may be a group of any number of WTRUs (e.g., a group of V2X WTRUs) in a group transmission (pre-) configured to share either sensing information and resource selection information between group members (e.g., WTRUs). For example, according to an embodiment, a (e.g., one) group member WTRU may perform sensing and resource selection and, e.g., transmit (e.g., resulting and / or other) assisting resource information to the other member WTRUs.

[0102] According to embodiments, the WTRU may be (pre-) configured with any number of periodicities for aiding transmission, e.g., according to (respectively, for, etc.) any number of resource pools. For example, according to embodiments, the periodicity of aiding transmission may be (e.g., determined, configured, etc.) according to (e.g., based on, configured, etc.) (e.g., based on, identical to, etc.) a per-slot bitmap, e.g., a (pre-)configured length for each SL resource pool. According to embodiments, the WTRU may be (pre-) configured with a set of aiding transmission windows, e.g., a set of consecutive aiding transmission windows in a resource pool. According to embodiments, the aiding WTRU may perform aiding transmission at any (e.g., each) configured period and / or within any (e.g., each) aiding transmission window.

[0103] According to an embodiment, the assisting WTRU may randomly select a timing instance for the assisting transmission within, for example, the assisting transmission period and / or window. According to an embodiment, the assisting WTRU may perform the assisting transmission according to an offset, such as, for example, an offset (e.g., slot, window, frame, time, etc.) from the start of the assisting transmission period and / or window. For example, the offset may be zero slots, which is the start of the assisting transmission period and / or window. According to an embodiment, the offset may be (pre-) configured, for example, according to a resource pool (e.g., based on, per, etc.).

[0104] According to an embodiment, the periodicity of the assistance transmissions may be associated with any of the V2X data group, the WTRU group, the QoS requirement associated with the assistance resource information, and the CBR. According to an embodiment, a small periodicity may be applied, for example, when having a low latency requirement for the V2X data transmission. According to an embodiment, the assisting WTRU may decrease the periodicity of the assistance transmissions (e.g., increase the number of assistance transmissions), for example, when the (e.g., measured, determined, etc.) CBR falls below a (pre-)configured threshold. According to an embodiment, in such a case, for example, the (e.g., more available) assistance information for the aided WTRU may be increased without increasing channel congestion.

[0105] According to an embodiment, the supporting WTRU may indicate a periodicity of the assistance transmission. For example, according to an embodiment, the supporting WTRU may transmit information indicating the periodicity of the assistance transmission in a reservation period indication bit field in the SCI of the assistance transmission. According to an embodiment, the supported WTRU may determine, e.g., based on the reservation period indication bit field, any of the V2X application(s), V2X data group, and QoS requirement associated with the assistance resource set information carried in the assistance transmission. According to an embodiment, in such case, the supported WTRU may select resources from the supporting resource set for SL transmission, e.g., for any of the V2X application, V2X data group, and QoS requirement of its SL TB, according to (e.g., based on, as indicated, etc.) the reservation period indication bit field.

[0106] FIG. 5 is a diagram illustrating an assistance transmission providing resource set information according to an embodiment.

[0107] According to an embodiment, for example, with reference to FIG. 5, an assisting transmission (e.g., transmitted by a WTRU) may provide resource set information to (e.g., other) WTRUs within (e.g., a particular) proximity, for example. According to an embodiment, the assisting WTRU may perform sensing to select candidate resources to be included in the assisting resource set, for example. According to an embodiment, the candidate assisting resources in the assisting resource set may be single-slot assisting resources spanning a (e.g., reference) number of subchannels. According to an embodiment, the assisting WTRU may determine any of the following sensing parameters: (1) a resource pool; (2) a sensing window 501 length; (3) a reference transmission window 502 length; (4) a reference number of subchannels; (5) a reference RSRP threshold; and (6) a minimum number of resources (e.g., needed, requested, etc.) for the resource set.

[0108] According to an embodiment, for example, in the case of a resource pool as a sensing parameter, the resource pool of the assisting resource set may be the same as that used for the assisting transmission. According to an embodiment, the resource pool for (e.g., used, associated, etc.) the assisting resource information may be (pre-)configured for any of the V2X application, data group, WTRU group, etc. According to an embodiment, the resource pool used for, for example, a V2X WTRU in a DRX transition period and a WTRU with battery constraints may either be dedicated or (pre-)configured for such WTRU group (e.g., a V2X WTRU in a DRX transition period and a WTRU with battery constraints). According to an embodiment, for example, in the case of a sensing window 501 length (e.g., sensing window 501 length as a sensing parameter), the sensing window length may be any value (e.g., indicated by any value), such as, for example, a time value (e.g., 100 ms, 1000 ms, etc.). According to an embodiment, for example, in the case of a length of the reference transmission window 502 (e.g., a length of the reference transmission window 502 as a sensing parameter), the reference transmission window length may be any value (e.g., indicated by any value), such as, for example, a time value (e.g., 10 ms, 20 ms, 100 ms, etc.). According to an embodiment, such a length (e.g., a parameter, value, etc. of the reference transmission window) may be associated with (e.g., may depend on) any of the V2X data group, WTRU group, and QoS requirements supported by the aiding resource information. For example, a low latency V2X data group may use a small transmission window.

[0109] According to an embodiment, for example, in the case of a reference number of subchannels as a sensing parameter, the reference number of subchannels may be a (pre)configured value including, for example, 1, 2, 4, etc. According to an embodiment, the WTRU may select the reference number of subchannels according to, for example, any of the V2X data group, the WTRU group, and the QoS requirement of the assistance resource information. For example, the WTRU may select a small reference number of subchannels for any of the V2X data group and the WTRU group using a periodic small packet size. According to an embodiment, for example, in the case of a reference RSRP threshold as a sensing parameter, it may be, for example, a measured RSRP value used to determine whether a resource may be included in the assistance resource set. According to an embodiment, the reference RSRP threshold may be based on any of the measured RSRP, the L1 priority decoded in the resource, and the reference TX priority.

[0110] According to an embodiment, the reference TX priority may be (pre-)configured and associated with any of the V2X data group, WTRU group, and QoS needs (e.g., requirements) of the assisting resource information. According to an embodiment, for example, where the sensed parameter is a minimum number of required (e.g., used, required, requested, etc.) resources in a resource set. According to an embodiment, the minimum number of resources may be given (e.g., referred to) as X%, where X may be, for example, a ratio (e.g., 20%, 35%, 50%, etc.) of (1) the number of requested resources in the assisting resource set to (2) the total number of candidate resources in the reference transmission window, determined according to (based on) any of the V2X data group, WTRU group, and QoS requirements associated with the assisting resource set information. For example, according to an embodiment, the WTRU may include more candidate resources (eg, 50% in the supporting resource set) for either reliable V2X data transmission and / or VRU, for example.

[0111] According to an embodiment, the supporting WTRU may determine (e.g., select) a set of selected candidate resources according to (e.g., derived from) the sensing result and include such set in, for example, the assistance transmission 504. According to an embodiment, the supporting WTRU may include any number of sensing parameters, such as any of the sensing parameters mentioned above, in the assistance information. According to an embodiment, the supporting WTRU may indicate (e.g., transmit a message indicating) an index of a reference sensing configuration applied to the candidate resource set. For example, according to an embodiment, a reference sensing configuration may be (pre-) configured for either the supporting WTRU or the supported WTRU. According to an embodiment, the supporting WTRU may include (e.g., transmit, transmit, etc.) an indication of the SCI to indicate that the data carried on the PSSCH may be assistance information, for example including any of the supporting resource set and related parameters.

[0112] According to an embodiment, the aided WTRU may determine the reference sensing parameters according to (e.g., based on) any of the sensing configuration indication and the set of sensing parameters included in the aiding transmission. According to an embodiment, the reference transmission window associated with the aiding resource set information may be the slot in which the aiding transmission is received. According to an embodiment, the start of the reference transmission window may be (pre-) configured using an offset, which may be, for example, a number of slots from (e.g., with respect to) the slot in which the aiding transmission is received. According to an embodiment, the aided WTRU may calculate a transmission window associated with the received aiding resource set and determine a subset (e.g., of the set) of received aiding resources that may be used for (e.g., its) SL transmission, for example, based on the purple window of the WTRU's actual transmission window 503 shown in FIG. 4. According to an embodiment, the actual transmission window 503 may be determined according to (e.g., based on) the packet delay budget (PDB) of the transmitted TB.

[0113] According to an embodiment, the supporting WTRU may include a priority value associated with each supporting resource in the supporting resource set information. According to an embodiment, the supported WTRU may calculate a relative RSRP threshold for each supporting resource, for example, according to a (e.g., respective) reception priority associated with each resource and a priority associated with the actual SL transmitter 505 of the supported WTRU. According to an embodiment, the supported WTRU may determine a subset of supporting resources having (e.g., comprising) an RSRP value lower than the (e.g., calculated) relative RSRP threshold. According to an embodiment, the supported WTRU may select (e.g., randomly) a resource from among the determined supporting resource subset, for example, for the (e.g., actual) SL transmitter 505. According to an embodiment, the supported WTRU may perform sensing on / for the received supporting resources, for example, for resource selection for the (e.g., actual) SL transmitter 505.

[0114] According to an embodiment, the supported WTRU may receive and / or apply an assisting resource set transmission, e.g., for a first SL transmission, when the supported WTRU either transitions to an active / wake state or starts performing sensing. According to an embodiment, the supported WTRU may stop receiving an assisting transmission(s), e.g., when sensing information is (e.g., becomes) available for resource selection, i.e., when the supported WTRU may accumulate sensing data within or for the complete sensing window.

[0115] According to an embodiment, the WTRU may determine not to perform an assistance transmission in case of a triggering (e.g., triggering) condition (e.g., occurrence). According to an embodiment, the WTRU may determine not to perform a triggered assistance transmission in case of any of the following: (1) the WTRU TX-RX distance is greater than a threshold configured for a resource pool of WTRU-to-WTRU assistance; (2) the WTRU battery level is less than a threshold configured for WTRU assistance; (3) the measured CBR is greater than a threshold configured for WTRU assistance; or (4) the WTRU receives such a triggered assistance transmission from another WTRU.

[0116] UE Determination of Information in and / or for Assistance Transmission According to an embodiment, the WTRU may determine the content included in the assistance information (e.g., of an assisting transmission). According to an embodiment, the assisting WTRU may provide (e.g., information indicative of) a set of resources in the assisting transmission. According to an embodiment, the assisting WTRU may include an indication (e.g., information) regarding any number of triggering conditions of the assisting transmission. According to an embodiment, such an indication (e.g., information indicative of) may be any of a collision detection indication, a high CBR indication, a range indication, and a consecutive TB decoding failure indication. According to an embodiment, for X triggering conditions, the number of bits of this indication (e.g., required for, used for) may be [log2X].

[0117] According to an embodiment, the helping WTRU may transmit any of the following (e.g., information) in (e.g., along with) the assisting transmission: (1) congestion control information; (2) resource pool indication; (3) CSI associated with the helping resource, (4) signal measurements associated with the helping resource; (5) interference measurements associated with the helping resource; (6) grant free resource indication; and (7) the speed and / or location of the helping WTRU. According to an embodiment, when providing congestion control information (e.g., CBR information), the WTRU may include a CBR measurement in the helping transmission, for example, according to (e.g., based on) any of the zone ID information and the CBR value. For example, according to an embodiment, the WTRU may transmit the CBR information if any of the zone ID change and the measured CBR value exceed a (pre-)configured threshold.

[0118] According to an embodiment, in the case of a resource pool indication, the WTRU may include an index of the resource pool(s) that may be used (e.g., used) by the supported WTRU in the aided transmission. According to an embodiment, in the case of CSI associated with the provided aiding resources (e.g., subchannel-based CSI report), the WTRU may include a CSI report associated with the aiding resources provided to another WTRU. According to an embodiment, in the case of signal measurements of the aiding resources, it may be an RSRP value for any or each aiding resource. According to an embodiment, in the case of interference measurements of the aiding resources, it may be an RSSI value for any or each aiding resource. According to an embodiment, in the case of indicating grant-free resources, the WTRU may indicate the type of the provided aiding resource set. For example, according to an embodiment, the WTRU may indicate that the aiding resources may be used in a grant-free manner (e.g., without resource reservation).

[0119] According to an embodiment, the assistance information may include an indication of a resource reservation associated with the assistance transmission (e.g., a resource reservation of the supported WTRU that may be reselected according to the assistance information of / by the supported WTRU). According to an embodiment, for example, such an indication may include any of an L1 destination ID and / or an L1 source ID, an L2 destination ID and / or an L2 source ID, and a link ID.

[0120] According to an embodiment, for example, as described above, the helping WTRU may include information regarding (e.g., associated with) a transmission window associated with a resource set carried in the helping transmission, e.g., such information may include any of T1 and T2. According to an embodiment, any of the T1 and T2 values ​​(e.g., in a slot) may be for the helping transmission. According to an embodiment, such T1 and / or T2 values ​​may provide a reference timing to the helped WTRU, e.g., to interpret the resource set (e.g., correctly).

[0121] According to an embodiment, there may be any number of aiding transmission types. According to an embodiment, the aiding WTRU may perform aiding transmission according to (e.g., based on) any of the SL channels and signaling. For example, according to an embodiment, the aiding WTRU may perform aiding transmission according to (e.g., based on) any of the following SL channels and / or signaling (e.g., over channels): PSCCH (e.g., standalone PSCCH); PSFCH; physical SL collision indication channel; PSSCH (e.g., MAC CE signaling, RRC signaling, etc.), and physical SL aiding indication channel.

[0122] According to an embodiment, the assistance information transmission may be performed via (e.g., with, on, through, in, etc.) a (e.g., new) physical SL assistance indication channel. According to an embodiment, the WTRU may transmit the assistance information in a new SL PHY channel, such as, for example, a physical SL assistance indication channel. According to an embodiment, such a (e.g., new) channel may have (e.g., consist of, comprise, utilize, be associated with, etc.) any number (e.g., types) of (e.g., different) indications (e.g., assistance indications). According to an embodiment, such indication(s) may be determined according to either (1) an assistance request transmission and a configuration (e.g., pre-configuration) of each (e.g., for) resource pool. According to an embodiment, the assistance indication may be (e.g., and / or may include) any of (1) a collision indication, (2) a half-duplex indication, (3) a PSFCH transmission indication, and (4) a UL transmission indication.

[0123] According to an embodiment, the collision indication may indicate, for example, detection of a collision (e.g., a detected collision) with a SP-based resource reservation detected by the WTRU to which the assistance information is directed. For example, according to an embodiment, the indication may be one bit and may be transmitted in a resource associated with the reserved resource between the collision detection and the next transmission instance of the resource reservation. According to an embodiment, an assisted WTRU receiving such information (e.g., a collision indication) may trigger either preemption and resource reselection. According to an embodiment, the half-duplex indication may indicate an upcoming SL transmission, for example, indicating a non-receiving slot(s). According to an embodiment, the half-duplex indication may include, for example, a bit field to convey the slot(s) index of the non-receiving slot(s). According to an embodiment, when receiving a half-duplex indication, the assisted WTRU may avoid SL transmission in the slot(s) (e.g., associated with (e.g., indicated in / by) the half-duplex indication).

[0124] According to an embodiment, the PSFCH transmission indication may indicate an upcoming PSFCH transmission. According to an embodiment, the PSFCH transmission indication may include, for example, a bit field to indicate whether a PSFCH transmission is reserved in the nearest PSFCH slot of a resource pool. According to an embodiment, the PSFCH indication may include PSFCH slot indices of all reserved PSFCH transmissions. According to an embodiment, when receiving such a PSFCH transmission indication, the supported WTRU may avoid transmitting a PSSCH in (e.g., any) slot that may result in a PSFCH transmission in the indicated slot(s). In such a case, according to an embodiment, the supporting WTRU may avoid missing a PSFCH due to, for example, multiple PSFCH transmissions in one slot. According to an embodiment, the UL transmission indication may indicate an upcoming UL transmission. According to an embodiment, the UL transmission indication may include, for example, a bit field to indicate a slot in which a UL transmission is scheduled. According to an embodiment, when receiving a UL transmission indication, the supported WTRU may avoid transmitting a PSSCH in (e.g., such) indicated slot(s). In such a case, according to an embodiment, the supporting WTRU may avoid intra-WTRU interference, eg, interference from UL transmission to (affecting, into, etc.) SL reception.

[0125] According to embodiments, the WTRU may determine (e.g., select) resources for (e.g., associated with) the assistance transmission. According to embodiments, the WTRU may be configured (e.g., pre-configured) with a (e.g., dedicated, only, specifically, etc.) resource allocation for the assistance information transmission, which may occur on (e.g., transmitted via, using, etc.) either the PSSCH or the new PHY indication channel (e.g., as described above). According to embodiments, the (e.g., such) resource allocation may be any of a resource pool and a set of time and frequency resources allocated within the resource pool. According to embodiments, such resources may not be used for or by (e.g., any) other V2X data transmission. According to embodiments, such time and / or frequency resources (e.g., set) may be any of (e.g., consisting of, comprising, including, having, etc.) a set of SL slots, a set of SL symbols, a set of subchannels, a set of PRBs, and a set of subcarriers. According to embodiments, such time and / or frequency resources may be configured as a separate region within / of a (e.g., pre-configured) resource pool configured for SL transmission.

[0126] According to an embodiment, the WTRU may determine (e.g., select) resources for the assisting transmission according to a PSSCH transmission associated by the supported WTRU. For example, according to an embodiment, the WTRU may determine (e.g., select) resources for an initial assistance indication transmission according to resources used for a PSSCH transmission associated with indication information (e.g., such as the indication information described above). According to an embodiment, for example, an indication channel having (e.g., comprising, including, etc.) a collision indication may use resources associated with resources of a PSSCH transmission in which a collision is detected. According to an embodiment, resources of a PSSCH transmission may be reserved via (e.g., with, within, by, etc.) semi-persistent reservation. According to an embodiment, such association of resources (e.g., such associated resources) may be determined according to any of the following: (1) starting subchannel and / or PRB index of the PSSCH transmission; (2) slot index of the PSSCH transmission; (3) WTRU source ID and / or destination ID of the supported WTRU; (4) SLID of the SL link to which the assistance information is directed; and (5) total resources configured (e.g., pre-configured) for the assistance transmission.

[0127] According to an embodiment, the supporting WTRU may determine frequency resources for the initial support indication transmission, for example within any of the subchannels and PRBs used for the PSSCH transmission. For example, according to an embodiment, the indication channel may use any of the subchannels and PRBs of the PSSCH transmission with the lowest index. According to an embodiment, the subchannels and PRBs may be selected according to a modular function of any of the WTRU ID (e.g., in decimal format), the SL ID, and the total number of subchannels and / or PRBs used for the PSSCH transmission (e.g., performed with / on). According to an embodiment, a mapping of (e.g., between) the PSSCH subchannels and / or PRBs may be configured with dedicated frequency resources for the support indication channel. According to an embodiment, the WTRU may determine a set of subchannels and / or PRBs according to any of the index of the slot and the starting subchannel and PRB index of the PSSCH transmission. According to an embodiment, the WTRU may select any of the subchannels and PRBs from the set of subchannels and / or PRBs according to any of the WTRU source / destination ID and the SL ID. According to an embodiment, the WTRU may determine a PSFCH resource according to the PSSCH transmission (eg, as specified according to the 3GPP standard) and may transmit an initial support indication channel in the determined PSFCH resource.

[0128] According to an embodiment, the WTRU may determine resources for an assistance transmission according to an association between resources used for the assistance request and the corresponding information transmission. According to an embodiment, the WTRU may perform an assistance transmission including (e.g., conveying, indicating, etc.) the requested information, for example, when the WTRU receives an assistance request transmission. According to an embodiment, the WTRU may determine resources used for the assistance information transmission according to a configured association (e.g., with) of resources of the received corresponding assistance request. According to an embodiment, such a configured (e.g., pre-configured) association may be indicated, for example, explicitly or implicitly (e.g., as discussed below).

[0129] According to embodiments, there may be an explicit association between the assistance request and the resources of the information transmission. According to embodiments, the WTRU may explicitly indicate the SL resource allocation reserved for the assistance information transmission in a SL PHY control channel, such as the SL PHY assistance request channel. According to embodiments, the SL control information (SCI) may be carried in the assistance request channel and may include any of the following information: (1) an assistance request indication; (2) time and / or frequency resources allocated for the corresponding assistance information transmission; (3) any of the source ID and destination ID of the SL link for which the assistance request is intended.

[0130] According to an embodiment, the assistance request indication may indicate (e.g., convey) any of the type of assistance information requested and the content of the requested assistance information. For example, according to an embodiment, the WTRU may request assistance information including any of the collision indication, CSI, sensing results, intermediate sensing results, etc. According to an embodiment, each code point of the SCI bit field may correspond to any of the configured type of requested assistance information and the content of the requested assistance information.

[0131] According to embodiments, in the case of time and / or frequency resources allocated for corresponding assistance information transmission, the allocation (e.g., of time and / or frequency resources) may include multiple resources for either the initial transmission and the retransmission. For example, according to embodiments, a time gap of (e.g., with respect to) a slot may be applied to indicate the time resource associated with (e.g., with reference to, with respect to, etc.) the slot in which the request channel is transmitted. According to embodiments, an index of either the subchannel or the PRB may be indicated for the frequency resource allocation. According to embodiments, in the case of assistance information parameters, the WTRU may provide sensing parameters (e.g., as described above). According to embodiments, the WTRU may indicate either the buffer status and the packet size for which the assistance information is intended.

[0132] According to embodiments, there may be an implicit association between resources for assistance request and assistance information transmission. According to embodiments, the WTRU may perform an assistance request transmission including (e.g., without) a resource allocation for a corresponding assistance information transmission. According to embodiments, the WTRU may, for example, transmit an assistance request via (e.g., using, in, on, etc.) a SL PHY assistance request channel according to a PHY signal (e.g., a ZC-based sequence). According to embodiments, the WTRU may, for example, transmit an assistance request in a SL PHY assistance request channel including a set of bit fields (e.g., as described above) without (e.g., except for) a resource allocation for a corresponding assistance information transmission.

[0133] According to an embodiment, the helping WTRU may determine the SL slot for the initial assistance information transmission according to a timing offset (e.g., number of slots) between the assistance request and the corresponding information transmission. According to an embodiment, the timing offset may be configured (e.g., pre-configured) per type and / or content of the assistance information. For example, the collision indication may be configured with a time gap smaller than the available resource set. According to an embodiment, the timing offset (e.g., time gap) may be configured as a fixed value, such as, for example, a number of slots that allows the helping WTRU sufficient time to generate the assistance information. According to an embodiment, the helping WTRU may determine the frequency resource for the initial assistance information transmission according to any of the following parameters: (1) any index of the subchannel and PRB on which the assistance request is received; (2) the type of assistance information indicated in the assistance request transmission; (3) any source ID and destination ID of the SL link for which the assistance information is intended; (4) the link ID of the SL link for which the assistance information is intended; and (5) the total resources configured for the assistance transmission.

[0134] According to an embodiment, the helping WTRU may select one of the subchannels and PRBs for the assistance transmission according to a configured (e.g., pre-configured) association between (1) one of the subchannels and PRBs used for the request transmission and (2) the corresponding assistance transmission. According to an embodiment, such association (e.g., between (1) and (2)) may be a one-to-one mapping between the subchannels and / or PRBs used for both transmissions. For example, according to an embodiment, the WTRU may select one of the same subchannels and the same PRBs used for the assistance request transmission for the corresponding information transmission. According to an embodiment, the WTRU may select (e.g., determine) a subchannel that may include a PRB used for the associated request transmission. According to an embodiment, the helping WTRU may perform the retransmission of the assistance information according to a configured (e.g., pre-configured) pattern. According to an embodiment, such a pattern may be (e.g., includes, consists of, has, comprises, etc.) a sequence of time and / or frequency resources with reference to, for example, the determined resources of the initial transmission.

[0135] According to an embodiment, the WTRU may determine the assistance information. According to an embodiment, the assisting WTRU may determine a set of resources (e.g., included in, indicated in, etc.) of the assistant information according to any of sensing and resource selection, CSI measurement, and collision detection. According to an embodiment, the assisting WTRU may perform (e.g., two, any number, etc.) sensing and resource selection. According to an embodiment, the two sensing and resource selection may include any of sensing and resource selection for determining resources used for assistance transmission and sensing and resource selection for determining a set of resources for reporting in the assistance transmission.

[0136] According to an embodiment, the sensing and resource selection may be for determining resources to be used for the assisting transmission (e.g., may be used by the WTRU). According to an embodiment, the supporting WTRU may perform resource selection for the assisting transmission according to the sensing. According to an embodiment, the supporting WTRU may apply sensing parameters. According to an embodiment, the sensing parameters of the supporting WTRU (e.g., applied by) may be a resource pool to which resources are reported. For example, the supporting WTRU may select resources from a resource pool dedicated to the assisting transmission.

[0137] According to an embodiment, the sensing parameter of the helping WTRU (e.g., applied by it) may be the L1 priority. According to an embodiment, the L1 priority of the assisting transmission may be (pre-)configured. For example, the L1 priority may be set to the highest priority. According to an embodiment, the L1 priority of the assisting transmission may be the same as the L1 priority of the TB carried in the same transmission. According to an embodiment, the sensing parameter of the helping WTRU (e.g., applied by it) may be the remaining PDB. According to an embodiment, the remaining PDB of the assisting transmission may be (pre-)configured. For example, either a fixed value or a small value may be (pre-)configured. According to an embodiment, the helping WTRU may, for example, determine a waiting time for the assisting transmission based on the remaining PDB. According to an embodiment, the helping WTRU may, for example, determine a waiting time for the assisting transmission based on the remaining PDB. According to an embodiment, the remaining PDB of the assisting transmission request may be the same as that of the TB carried in the same transmission. According to an embodiment, the sensing parameter of the helping WTRU (e.g., applied by it) may be the number of subchannels used (e.g., to be used) for the assisting transmission.

[0138] According to an embodiment, the helping WTRU may determine either T1_assist or T2_assist for the assisting transmission request. According to an embodiment, T1_assist may be determined according to (e.g., based on) WTRU processing. According to an embodiment, T2_assist may be determined according to (pre-)configuration. That is, according to an embodiment, a fixed value (e.g., a) T2_assist may be configured (pre-) for the assisting transmission request. According to an embodiment, T2_assist may be determined by the remaining PDB of the TB. According to an embodiment, T2_assist may be determined according to the duration of the associated resource reservation. According to an embodiment, the helping WTRU may select T2_assist, for example, such that the helped WTRU may have enough time to receive the assisting transmission and reselect resources based on the received assisting resource set. According to an embodiment, for example, as shown in FIG. 4, when T1_TB is applied to resource set sensing, the helping WTRU may set T2_assist before T1_TB-Toffset.

[0139] According to an embodiment, sensing and resource selection may be performed to determine, for example, a set of resources to report in an assisting transmission. According to an embodiment, the helping WTRU may determine any number of sensing parameters. According to an embodiment, the helping WTRU may determine the sensing parameters according to any of the following: (1) a (pre-) configuration of (e.g., specific to) the resource pool; (2) an L1 priority indicated in a (e.g., previous) transmission received from the supported WTRU; (3) a number of sub-channels of a (e.g., previous) transmission received from the supported WTRU; (4) an RRC configuration (e.g., received, used) during link establishment from the supported WTRU; and (5) a parameter included in an assistance request received from the supported WTRU. According to an embodiment, the helping WTRU may determine the sensing parameters according to a received assistance transmission request content, for example, as described above.

[0140] According to an embodiment, the helping WTRU may determine the sensed parameters according to a (e.g., previous) transmission received from the helped WTRU. For example, according to an embodiment, the helping WTRU may apply any of the number of subchannels and the L1 priority of the previous transmission.

[0141] According to an embodiment, the assisting resources (e.g., resources used / indicated by, etc.) of the assisting resource set may be determined, for example, by the WTRU. According to an embodiment, the assisting resources may include a set of available resources that may be determined, for example, according to a sensing procedure. For example, according to an embodiment, the assisting WTRU may provide a set of assisting resources according to (e.g., from, based on, etc.) a set A determined according to (e.g., as a result of) the sensing procedure. According to an embodiment, in such a case, each assisting resource may be a candidate resource designated for the sensing procedure. According to an embodiment, the assisting resources (e.g., candidate resources) may be time / frequency resources occupying a single slot and any set of (e.g., a particular, several) contiguous subchannels used for sensing included in the corresponding resource pool and within (e.g., for) the corresponding resource pool and the associated transmission window.

[0142] According to an embodiment, the assisting resources may include a set of unavailable resources for transmission. For example, according to an embodiment, a peer WTRU, either unicast or groupcast, may indicate a set of slots that are unavailable to the supported WTRU (e.g., a set of slots that the peer WTRU may use, request, need, reserve, and transmit in). According to an embodiment, the supported WTRU may avoid (e.g., not select) a transmission resource that is included in the set of slots indicated by the assisting WTRU.

[0143] According to an embodiment, the WTRU may determine a transmission window associated with the assisting resource set. According to an embodiment, the resources in the assisting resource set may be indexed, for example, according to the candidate resources (e.g., sum, amount) in the associated transmission window. According to an embodiment (e.g., when indexing the assisting resource set), both the supporting WTRU and the supported WTRU may have the same interpretation (e.g., needs, requires, etc.) of time and frequency resources based on the index of the resources in the assisting resource set. According to an embodiment, for example, to have (e.g., achieve) such a same interpretation, both the supporting WTRU and the supported WTRU may have the same understanding (e.g., should have, shall have, must have, etc.) of the start and end of the transmission window.

[0144] According to an embodiment, the helping WTRU may receive an explicit indication in the helping transmission request, including, for example, either T1_TB or T2_TB. According to an embodiment, either T1_TB or T2_TB may be an absolute frame, subframe, or slot number. According to an embodiment, the indication value may be an offset (e.g., in slots) relative to the timing of the helping transmission request. According to an embodiment, such timing (e.g., such time) may be common to both the helping and assisted WTRUs and may not (e.g., cannot or will not) cause ambiguity in interpreting the window start, window end, and resource indexing. According to an embodiment, the helping WTRU may determine T2_TB by the remaining PDB included in the helping transmission request.

[0145] According to an embodiment, the helping WTRU may determine T1_TB according to any of: T2_assistTX (e.g., T2 of the helping transmission); a (pre-)configured offset (e.g., slot) between T2_assistTX and T1_TB; the timing of the helping transmission; and the timing of the helping transmission request. For example, according to an embodiment, the helping WTRU may determine T1_TB=T2_assistTX+offset, thereby determining a transmission window of [n+T1_TB, n+T2_TB], where n may refer to the timing (e.g., slot) of the helping transmission request. According to an embodiment, the (e.g., (pre-)configured) offset may allow sufficient time for the helped WTRU to receive the helping transmission and perform WTRU processing to perform resource selection based on the received helping transmission (e.g., shall allow, must allow, need to allow, etc.).

[0146] According to embodiments, the supporting WTRU may determine the transmission window according to either a reserved transmission timing or a predefined transmission window. For example, according to embodiments, the supporting WTRU may perform a supporting transmission (e.g., including information) providing a resource set for a next transmission by the supporting WTRU in a slot, such as slot X. According to embodiments, the supporting WTRU may determine the transmission window according to either a (pre-)configured transmission window for a reserved time resource (e.g., slot X), e.g., a transmission window starting at slot X with a (pre-)configured duration (e.g., slot). According to embodiments, the transmission window may end at slot X with a (pre-)configured duration (e.g., slot).

[0147] According to an embodiment, the above determinations and / or (e.g., any of) (e.g., associated) parameters may be common to both the helping WTRU and the helped WTRU, so that both WTRUs may have the same understanding of the start and end of the transmission window. According to an embodiment, for example, as a result of having such the same understanding, the helped WTRU may (e.g., correctly) interpret the resources in the resource set provided according to the indexing. According to an embodiment, the helping WTRU may determine a percentage of resources among (e.g., total) candidate resources for the transmission (e.g., in) that may be included in the set of resources reported to the helped WTRU. According to an embodiment, the helping WTRU may determine the percentage of resources among the total candidate resources in the transmission window according to any of the following: (1) (pre-)configuration (e.g., the percentage may be fixed at X%, where X may be equal to 20); (2) QoS requirement (e.g., the percentage may be X%, where X is based on L1 priority); (3) an indication in the received helping transmission request.

[0148] According to an embodiment, a set (e.g., any) number of assisting resources may be (pre-)configured to be associated with a (e.g., specific) resource pool. According to an embodiment, such number (e.g., of the set of assisting resources) may be included (e.g., signaled) in an RRC configuration, for example, during link establishment. According to an embodiment, such number may be indicated in an assistance request from the supported WTRU.

[0149] According to an embodiment, the WTRU may determine the assistance information when triggered by a CSI report. According to an embodiment, the supporting WTRU may include CSI information (e.g., either CQI and RI) along with the resource set, for example, in an assistance transmission. According to an embodiment, the supporting WTRU may determine the set of assistance resources according to (e.g.) CSI measurements of resources. According to an embodiment, the supporting WTRU may include the assisting resources for which the measured CSI value (e.g., CQI) exceeds a threshold (e.g., a (pre-)configured, CQI, etc.). According to an embodiment, the supporting WTRU may receive a CQI threshold in the assistance request from the supported WTRU. According to an embodiment (e.g., in addition to the above features), the supporting WTRU may include set resources for which the measured CQI exceeds, for example, either an average CQI value or a median CQI value obtained over all measured resources within the determined transmission window. According to an embodiment, if the size of the assisting resource set is fixed, the supporting WTRU may include, for example, a particular assisting resource with the highest measured CQI value.

[0150] According to an embodiment, the WTRU may determine assistance information in the case of either collision detection and HARQ NACK. According to an embodiment, the WTRU may include collision information in a PSFCH transmission, for example, if HARQ is enabled for the transmission(s) corresponding to the resource reservation for which a collision is detected. According to an embodiment, for example, the PSFCH format may include a bit field indicating a collision detected on a resource of the PSSCH associated with the HARQ ACK / NACK carried in the PSFCH. According to an embodiment, in such a case, the WTRU may transmit either or both of the HARQ ACK / NACK information and the associated collision detection indication on the PSFCH.

[0151] According to an embodiment, the WTRU may transmit a collision indication on a SL PHY channel (e.g., a physical SL collision indication channel), such that the physical SL collision indication channel can carry one bit of information (e.g., collision indication). According to an embodiment, the channel may be sequence-based, e.g., according to a (e.g., (pre)defined) sequence indicating either collision detection and / or no collision detection. According to an embodiment, such a sequence may be according to (e.g., based on) a ZC sequence with two (pre)defined periodic shifts. According to an embodiment, the resource of the physical SL collision indication channel may be (e.g., implicitly) associated with a PSSCH resource, e.g., a PSSCH resource on which an indicated collision is detected. According to an embodiment, if the collision indication is based on successive collision detections (e.g., as described above), the resource may be (e.g., implicitly) associated with the last PSSCH resource. According to an embodiment, the supporting WTRU may include a collision detection indication with a resource set in the supporting transmission, e.g., according to (e.g., based on) either MAC CE signaling and RRC signaling. According to an embodiment, the WTRU may periodically transmit a physical SL collision indication channel. According to an embodiment, the WTRU may transmit a physical SL collision indication channel triggered by a collision detection (eg, as described above).

[0152] According to an embodiment, there may be an indication of (e.g., of) a collision with a VRU transmission. According to an embodiment, the WTRU may identify (e.g., detect, determine, sense, etc.) a collision with a VRU transmission, for example, according to an indication of WTRU type (e.g., included, conveyed, signaled, indicated, etc.) in the SCI. For example, according to an embodiment, the indication of WTRU type in the SCI may include a value corresponding to (e.g., information indicative of) a VRU transmission. According to an embodiment, if the WTRU detects a collision with a VRU transmission, the WTRU may transmit (e.g., convey, signal, include, etc.) a collision indication indicating information. According to an embodiment, the collision indication may be included in a PHY control channel, and the collision indication may be configured with a set of values, at least one of which may indicate a collision with a VRU transmission (e.g., may correspond to and / or be associated with an indication of a collision).

[0153] According to an embodiment, when the supported WTRU receives (e.g., such) a collision indication, the supported WTRU may not consider the priority of the collided transmission and may determine to perform either preemption or resource reselection. According to an embodiment, performing either preemption or resource reselection may, for example, prioritize VRU transmissions (e.g., enable VRU prioritization) because, for example, a (e.g., particular) VRU may have hardware (e.g., software, physical, etc.) constraints (e.g., the VRU may not have a receiver) and the VRU may not (e.g., be able to) detect a collision (e.g., as a result of the constraint). According to an embodiment, when the supported WTRU receives a collision indication value associated with (e.g., corresponding to, indicative of, etc.) a collision with another VRU, the supported WTRU may determine to perform either preemption or resource reselection, for example, according to (e.g., based on) the priority value of the transmission.

[0154] According to an embodiment, the WTRU may perform operations and / or features when receiving an assisting transmission. According to an embodiment, the assisted WTRU may, for example, select (e.g., determine) an assistance message (e.g., any number, any type, etc.) to use (e.g., process, etc.) in association with the (e.g., any number) of assisting transmission(s).

[0155] According to an embodiment, the supported WTRU may receive any number (e.g., multiple) of assistance messages from any number (e.g., different) WTRUs. According to an embodiment, the supported WTRU may determine to use (e.g., process, select resources accordingly, etc.) any number of received assistance messages. According to an embodiment, the supported WTRU may determine which received assistance message to use (e.g., select any number of assistance messages) according to any of the source ID of the assistance message, the destination ID of the assistance message, and the destination ID of the TB. That is, according to an embodiment, in case of one unicast link, the supported WTRU may select an assistance message from a peer WTRU for unicast transmission with the peer WTRU. According to an embodiment, in case of groupcast transmission, the supported WTRU may select an assistance message from a WTRU in its group. According to an embodiment, the supported WTRU may determine (e.g., select) which (e.g., any number of) received assistance messages to use according to the timing of the assistance messages. For example, according to an embodiment, the supported WTRU may use the assistance message if the time gap between the assistance message and the TB arrival is less than a threshold, which may be determined, for example, by the PDB of the TB.

[0156] According to an embodiment, the supported WTRU may perform resource selection (e.g., select an assisting resource). According to an embodiment, the supported WTRU may select a (e.g., assisting) resource from among the set of assisting resources according to, for example, either a random selection or a CSI report.

[0157] According to an embodiment, the supported WTRU may, for example, receive (information indicating / identifying) a set of available resources from the supporting WTRU. According to an embodiment, when receiving the set of available resources from the supporting WTRU, the supported WTRU may, for example, perform sensing to determine the set of available resources (e.g., during / after a sensing procedure). According to an embodiment, the supported WTRU may determine the set of available resources according to a combination of the available resources from the sensing procedure and the set of available resources determined (e.g., signaled, indicated, received, etc.) according to the aiding information. According to an embodiment, the supported WTRU may determine the set of available resources according to an intersection between the set of available resources determined according to its sensing and the set of available resources determined according to the aiding information.

[0158] According to an embodiment, the supported WTRU may, for example, receive a set of unavailable resources from the supporting WTRU. According to an embodiment, the supported WTRU may, for example, exclude all unavailable resources (e.g., indicated, received, etc.) during either the sensing procedure or the resource (re)selection procedure when receiving the set of unavailable resources. According to an embodiment, the set of unavailable resources may be determined as a set of transmission slots associated with (e.g., used by, etc.) the supporting WTRU. According to an embodiment, the supported WTRU may determine to exclude any of the unavailable resources for transmission of a TB associated with the supporting WTRU.

[0159] According to an embodiment, the supported WTRU may receive a collision indication from the supporting WTRU. According to an embodiment, the resource collision indication (e.g., received from the supporting WTRU) may indicate a (e.g., potential) collision of any number of (e.g., reserved) resources. According to an embodiment, for example, when receiving a resource collision indication, the (e.g., supported) WTRU may determine to trigger resource selection / reselection.

[0160] According to an embodiment, the supported WTRU may receive assistance information from any number (e.g., multiple, two or more, etc.) of supporting WTRUs. According to an embodiment, the supported WTRU may receive assistance information from any number of supporting WTRUs. According to an embodiment, the WTRU may process the received assistance information and the WTRU's (e.g., own) sensing results simultaneously (e.g., jointly, together, in parallel) and may determine a superset of combined assistance information. According to an embodiment, the superset of resources (e.g., associated with the superset of combined assistance information) may be a value (e.g., a certain percentage, X, X%, etc.) of total resources within a transmission window determined by the configured processing time of the SL TB and the PDB. According to an embodiment, such a value (e.g., a certain percentage, X) may be configured (e.g., pre-configured) per QoS (e.g., per priority, per resource pool, etc.).

[0161] According to an embodiment, the WTRU may determine the candidate resource set according to (e.g., based on) any superset of available and preferred resources. According to an embodiment, (e.g., such) superset (e.g., of available and / or preferred resources) may be determined according to (e.g., based on) any of (1) the number of resource sets in which the assisting resources are included, and (2) the average RSRP and L1 priority of the candidate resources included in the assistance information.

[0162] According to an embodiment, in case of a superset determined according to the number of resource sets in which the assisting resource is included, such resource set may include any of the received assisting resource set and the resource set determined by sensing (e.g., set A). According to an embodiment, the (e.g., each) assisting resource set may include, for example, any of the available resources and the preferred resources determined by any (e.g., each) assisting WTRU. According to an embodiment, the supported WTRU may count the number of resource sets in which the candidate resource is included. According to an embodiment, the supported WTRU may rank all resources in descending order according to (e.g., based on) the count and may include a first percentage (e.g., X%) of resources in the superset of candidate resources for TB transmission. According to an embodiment, the superset may include resources that (e.g., according to) most WTRUs identify as available and / or preferred.

[0163] According to an embodiment, in case of a superset determined according to either the average RSRP and L1 priority of the candidate resources included in the assistance information, the supported WTRU may process all of either the available and preferred resources in all assisting resource sets received together with (e.g., simultaneously) its own sensing. For example, according to an embodiment, the supported WTRU may calculate the average RSRP of the candidate resources according to (e.g., based on) the reported RSRP for the same resources and filter out resources having (e.g., comprising) an average RSRP higher than a certain value (e.g., a configured / preconfigured threshold). According to an embodiment, such a value (e.g., threshold) may be configured for each L1 priority pair, whereby, for example, a priority of TB is transmitted by the supported UE and the decoded priority is associated with the candidate resource (e.g., the priority decoded in ). According to an embodiment, the WTRU may determine (e.g., select, signal, etc.) the candidate resource set according to (e.g., based on) the superset of unavailable resources included in the received assisting resource set (e.g., indicated by ) and the WTRU's own sensing results, such as set A. According to an embodiment, the supported WTRU may exclude any or all of the unavailable resources received from set A.

[0164] According to an embodiment, the supported WTRU may determine whether to perform (e.g., whether, necessity, requirement, etc.) a resource (re)assessment. According to an embodiment, the supported WTRU may determine whether (e.g., whether there is) a need to perform a resource (re)assessment (e.g., or) depending on any of the following: According to an embodiment, the supported WTRU may determine whether to perform (e.g., whether, necessity, requirement, etc.) a resource (re)assessment according to any of the timing of the assistance information message and the remaining PDB of the TB. According to an embodiment, for example, the WTRU may determine not to perform resource (re)assessment if the remaining PDB of the TB is less than a threshold value after receiving the assistance information message. According to an embodiment, the supported WTRU may perform resource (re)assessment if the remaining TB of the PDB does not exceed a threshold value.

[0165] According to an embodiment, the supported WTRU may determine (e.g., whether to perform, necessity, requirement, etc.) to perform resource (re)assessment according to the amount of assisting resources (e.g., total number of either transmission resources and slots) and either the window of the assisting resources. For example, according to an embodiment, the supported WTRU may determine not to perform resource (re)assessment if either the number of assisting resources and the assisting resource window size are smaller than a (e.g., respective) threshold. According to an embodiment, the supported WTRU may perform resource (re)assessment if such threshold is not exceeded. According to an embodiment, such an approach for resource (re)assessment allows the WTRU to have (e.g., sufficient) resources for selection. According to an embodiment, the supported WTRU may determine (e.g., whether to perform, necessity, requirement, etc.) to perform resource (re)assessment according to either the QoS of the TB and the CBR of the resource pool. For example, according to an embodiment, the supported WTRU may determine to perform resource (re)evaluation of either a high priority TB or a high measured CBR, and the supported WTRU may determine not to perform resource (re)evaluation of either a low priority TB or a low measured CBR.

[0166] According to an embodiment, the supported WTRU may, for example, determine whether to use (e.g., whether to use) the assistance information from the supporting WTRU. According to an embodiment, the supported WRTU may determine whether to use the assistance information (e.g., the set of available resources transmitted from the supported WTRU) according to a distance between the supporting WTRU and the supported WTRU. According to an embodiment, the supported WRTU may determine whether to use the assistance information (e.g., the set of available resources transmitted from the supporting WTRU) according to, for example, a received signal strength from the supporting WTRU. According to an embodiment, the supported WRTU may determine whether to use the assistance information (e.g., the set of available resources transmitted from the supporting WTRU) according to a CBR of a resource pool. According to an embodiment, for example, the WTRU may not determine whether to use or decode the assistance information if, for example, the CBR is less than a threshold. According to an embodiment, such an supported WRTU may determine to use the assistance information if the CBR is greater than a threshold. According to an embodiment, the supported WRTU may determine whether to use the assistance information (e.g., the set of available resources transmitted from the supporting WTRU) according to the QoS of the TB. For example, according to an embodiment, the WTRU may determine to use and / or decode the assistance information if the priority of the TB is greater than a threshold, and otherwise determine not to use the assistance information. According to an embodiment, the supporting WRTU may determine whether to use the assistance information (e.g., the set of available resources transmitted from the supporting WTRU) according to the timing of receiving the assistance information.

[0167] According to an embodiment, the supported WTRU may determine either the distance between the supporting WTRU and itself and the received signal strength from the supporting WTRU. According to an embodiment, the supported WTRU may determine whether to use the assistance information transmitted from the supporting WTRU according to the distance between the supporting WTRU and the supported WTRU. For example, according to an embodiment, if the distance between the supporting WTRU and the supported WTRU is less than a (e.g., distance) threshold, the supported WTRU may use the assistance information received from the supporting WTRU, otherwise the supported WTRU may not use the assistance information.

[0168] According to embodiments, the (e.g., distance) threshold may be determined according to any of various method parameters and / or features, such as, for example, one or any combination of the following, as discussed below: According to embodiments, the (e.g., distance) threshold may be determined, for example, according to a minimum communication range (MCR) indicated in an assistance message. For example, according to embodiments, the supporting WTRU may indicate, for example, the MCR to use in its assistance information. According to embodiments, the supported WTRU may determine the distance threshold according to (for example, as) the MCR indicated by the supporting WTRU. According to embodiments, the (e.g., distance) threshold may be determined by the QoS of the TB. For example, according to embodiments, the WTRU may be configured with a mapping between (e.g., any number of) distance thresholds and (e.g., any number of) priorities of the TB. According to embodiments, such a WTRU may (e.g., then) determine the distance threshold according to (e.g., matching) the QoS of the TB (e.g., any of the TB priority, delay, and / or reliability). According to embodiments, the (e.g., distance) threshold may be determined according to the CBR of the resource pool. For example, according to an embodiment, a WTRU may be configured with a mapping between a (e.g., any, respective) CBR range and a (e.g., one, any, respective) distance threshold. According to an embodiment, such a WTRU may (e.g., then) determine the distance threshold according to the measured CBR of the resource pool.

[0169] According to an embodiment, the WTRU may determine, for example, a received signal strength for a signal received from a helping WTRU. According to an embodiment, the supported WTRU may determine (e.g., whether to use) the assistance information according to a received signal strength (e.g., one of RSSI and RSRP) of a message (e.g., signal) associated with the assistance information. For example, according to an embodiment, if the received signal strength is less than a threshold, the supported WTRU may use the assistance information (e.g., from the helping WTRU). Otherwise, if the received signal strength does not exceed a threshold, the supported WTRU may not use such assistance information.

[0170] According to an embodiment, the received signal strength threshold may be determined according to either the transmit power and the minimum received signal strength threshold indicated by the assisting WTRU. According to an embodiment, the received signal strength threshold may be determined by the QoS of the TB. For example, according to an embodiment, a WTRU may be (pre-) configured with a mapping between a (e.g., one, each, any, etc.) minimum received signal strength threshold and a (e.g., one, each, any, etc.) priority and reliability value of the TB. According to an embodiment, such a WTRU may (e.g., then) determine to use (e.g., whether to use) the assistance information according to either the transmitted TB and its measured received signal strength. According to an embodiment, the received signal strength threshold may be determined according to the CBR of the resource pool. For example, according to an embodiment, a WTRU may be configured with a mapping between each CBR range and the received signal strength threshold. According to an embodiment, such a WTRU may (e.g., then) determine the received signal strength threshold according to, for example, the measured CBR of the resource pool.

[0171] According to an embodiment, the WTRU may determine a transmission time of (e.g., for) the assistance information. According to an embodiment, the supported WTRU may determine whether (e.g., whether to) decode and use the assistance information according to, for example, the transmission time of the assistance information. For example, according to an embodiment, the supported WTRU may determine either not to decode and not to use the assistance information for a time T (e.g., period, T slots, etc.) prior to the transmission resource. According to an embodiment, the value of T may be determined according to any of the resource pool (e.g., its (pre)configured), the capacity of the WTRU, the QoS of the TB, and / or the CBR of the resource pool.

[0172] conclusion Although the features and elements are described above in certain combinations, one skilled in the art will understand that each feature or element may be used alone or in any combination with the other features and elements. Furthermore, the methods described herein may be implemented in a computer program, software, or firmware embodied in a computer-readable medium for execution by a computer or processor. Examples of non-transitory computer-readable storage media include, but are not limited to, read-only memory (ROM), random access memory (RAM), registers, cache memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magneto-optical media, and optical media such as CD-ROM disks and digital versatile disks (DVDs). A processor in association with software may be used to implement a radio frequency transceiver for use in a UE, a WTRU, a terminal, a base station, an RNC, or any host computer.

[0173] Further, in the above embodiments, processing platforms, computing systems, controllers, and other devices including converging points / servers including constraint servers and processors are described. These devices may include at least one central processing unit ("CPU") and memory. In accordance with the practices of those skilled in the art of computer programming, references to acts and symbolic representations of operations or instructions may be performed by various CPUs and memories. Such acts and operations or instructions may be referred to as being "executed," "computer-executed," or "CPU-executed."

[0174] Those of ordinary skill in the art will appreciate that the operations and symbolically represented operations or instructions include the manipulation of electrical signals by the CPU. The electrical system represents data bits that can cause a resultant transformation or reduction of the electrical signals, and maintains the data bits in memory locations of the memory system, thereby reconfiguring or otherwise altering the operation of the CPU and the processing of other signals. The memory locations in which the data bits are maintained are physical locations that have particular electrical, magnetic, optical, or organic properties that correspond to or represent the data bits. It should be appreciated that the exemplary embodiments are not limited to the platforms or CPUs mentioned above, and that other platforms and CPUs may support the methods provided.

[0175] The data bits may also be maintained on a computer readable medium, including magnetic disks, optical disks, and any other volatile (e.g., random access memory ("RAM")) or non-volatile (e.g., read only memory ("ROM")) mass storage system readable by a CPU. The computer readable medium may include computer readable media that resides exclusively on a processing system, or distributed, cooperative, or interconnected among multiple interconnected processing systems that may be local or remote to a processing system. It is understood that representative embodiments are not limited to the memories described above, and that other platforms and memories may support the methods described.

[0176] In an example embodiment, any of the operations, processes, etc. described herein may be implemented as computer-readable instructions stored on a computer-readable medium. The computer-readable instructions may be executed by a processor of a mobile unit, a network element, and / or any other computing device.

[0177] There is little distinction between hardware and software implementations of aspects of the system. The use of hardware or software is generally (though not always, in certain circumstances the choice between hardware and software may be significant) a design choice that implies a cost vs. efficiency tradeoff. There may be a variety of vehicles (e.g., hardware, software, and / or firmware) in which the processes and / or systems and / or other techniques described herein may be effective, and the preferred vehicle may vary depending on the context in which the processes and / or systems and / or other techniques are deployed. For example, if an implementer determines that speed and accuracy are paramount, the implementer may select a primarily hardware and / or firmware vehicle. If flexibility is paramount, the implementer may select a primarily software implementation. Alternatively, the implementer may select some combination of hardware, software, and / or firmware.

[0178] The foregoing detailed description has illustrated various embodiments of devices and / or processes through the use of block diagrams, flow charts, and / or examples. To the extent that such block diagrams, flow charts, and / or examples include one or more functions and / or operations, those skilled in the art will appreciate that each function and / or operation in such block diagrams, flow charts, or examples may be individually and / or collectively implemented by a wide variety of hardware, software, firmware, or substantially any combination thereof. Suitable processors include, by way of example, general purpose processors, special purpose processors, conventional processors, digital signal processors (DSPs), multiple microprocessors, one or more microprocessors in association with a DSP core, controllers, microcontrollers, application specific integrated circuits (ASICs), application specific standard products (ASSPs), field programmable gate array (FPGA) circuits, any other type of integrated circuit (IC), and / or state machines.

[0179] Although features and elements are provided above in specific combinations, those of ordinary skill in the art will understand that each feature or element can be used alone or in any combination with other features and elements. The present disclosure is not limited in terms of the specific embodiments described in this application, which are intended as examples of various aspects. As will be apparent to those skilled in the art, many modifications and variations can be made without departing from the spirit and scope of the present invention. No element, operation, or instruction used in the description of this application should be construed as critical or essential to the invention unless expressly set forth as such. In addition to those enumerated herein, functionally equivalent methods and apparatuses within the scope of the present disclosure will be apparent to those skilled in the art from the foregoing description. Such modifications and variations are intended to fall within the scope of the appended claims. The present disclosure is to be limited only by the terms of the appended claims, along with the full scope of equivalents to which such claims are entitled. It is to be understood that the present disclosure is not limited to any particular method or system.

[0180] It should also be understood that the terms used herein are intended to describe particular embodiments (e.g., only) and are not intended to limit the invention. As used herein, "user equipment," and its abbreviation "UE," when referred to herein, may mean (1) a wireless transmit and / or receive unit (WTRU), such as the described infrastructure, (2) any of the several embodiments of a WTRU, such as the described infrastructure, (3) a wireless-enabled and / or wired-enabled (e.g., tethered) device configured with some or all of the structure and functionality of a WTRU (e.g., the described infrastructure) as illustrated, (4) a wireless-enabled and / or wired-enabled device configured with less than all of the structure and functionality of a WTRU (e.g., the described infrastructure), or (5) the like. Details of an exemplary WTRU that may represent any WTRU enumerated herein.

[0181] In certain representative embodiments, some portions of the subject matter described herein may be implemented via application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), digital signal processors (DSPs), and / or other integrated formats. However, those skilled in the art will recognize that some aspects of the embodiments disclosed herein may be equivalently implemented in whole or in part in an integrated circuit as one or more computer programs running on one or more computers (e.g., as one or more programs running on one or more computer systems), as one or more programs running on one or more processors (e.g., as one or more programs running on one or more microprocessors), as firmware, or as substantially any combination thereof, and that designing circuitry and / or writing software and / or firmware code is within the skill of those skilled in the art in light of this disclosure. Furthermore, those skilled in the art will recognize that the mechanisms of the subject matter described herein may be distributed as a program product in various forms, and that the exemplary embodiments of the subject matter described herein apply regardless of the particular type of signal-bearing medium used to actually effect the distribution. Examples of signal bearing media include, but are not limited to, recordable type media such as floppy disks, hard disk drives, CDs, DVDs, digital tape, computer memory, and transmission type media such as digital and / or analog communications media (e.g., fiber optic cables, wave guides, wired communications links, wireless communications links, etc.).

[0182] The subject matter described herein may in some cases depict different components that are included within or connected to different other components. It should be understood that such illustrated architectures are merely examples, and that in fact many other architectures that achieve the same functionality may be implemented. Conceptually, any arrangement of components to achieve the same functionality is effectively "associated" such that the desired functionality may be achieved. Thus, any two components combined herein to achieve a particular functionality may be viewed as "associated" with one another such that the desired functionality is achieved, regardless of the architecture or intermediate components. Similarly, any two components so associated may also be considered to be "operably connected" or "operably coupled" with one another to achieve the desired functionality, and any two components that may be so associated may also be considered to be "operably coupled" with one another to achieve the desired functionality. Examples of operably coupleable include, but are not limited to, physically matable and / or physically interacting components, and / or wirelessly interacting and / or wirelessly interacting components, and / or logically interacting and / or logically interacting components.

[0183] With respect to the use of substantially any plural and / or singular term herein, one of ordinary skill in the art can convert from plural to singular and / or from singular to plural as appropriate to the context and / or application. Various singular / plural permutations may be expressly set forth herein for purposes of clarity.

[0184] In general, those skilled in the art will understand that the terms used in this specification, and particularly in the appended claims (e.g., the body of the appended claims), are generally intended as "non-limiting" terms (e.g., the term "including" should be interpreted as "including but not limited to," the term "having" should be interpreted as "having at least," and the term "including" should be interpreted as "including but not limited to"). Furthermore, those skilled in the art will understand that where a specific number of recitations of an introduced claim are intended, such intent is expressly set forth in the claim, and in the absence of such recitation, no such intent exists. For example, where only one item is intended, the term "single" or similar language may be used. To aid in understanding, the following appended claims and / or the description of this specification may include the use of the introductory phrases "at least one" and "one or more" to introduce the claim recitations. However, the use of such phrases should not be interpreted as meaning that the introduction of a claim recitation with the indefinite article "a" or "an" limits any particular claim that includes such an introduced claim recitation to embodiments that include only one such recitation, even if the same claim contains the introductory phrase "one or more" or "at least one" and an indefinite article such as "a" or "an" (e.g., "a" and / or "an" should be interpreted to mean "at least one" or "one or more"). The same applies to the use of definite articles used to introduce claim recitations. Moreover, those skilled in the art will recognize that even if a specific number of recitations of an introduced claim are explicitly recited, such recitation should be interpreted to mean at least the recited number (e.g., the simple recitation "two recitations" without other modifiers means at least two recitations, or more than two recitations).Furthermore, when notation similar to "at least one of A, B, and C" is used, such structure is generally intended as a person of ordinary skill in the art would understand the notation (e.g., "a system having at least one of A, B, and C" includes, but is not limited to, systems having only A, only B, only C, A and B together, A and C together, B and C together, and / or A, B, and C together). When notation similar to "at least one of A, B, or C" is used, such structure is generally intended as a person of ordinary skill in the art would understand the notation (e.g., "a system having at least one of A, B, or C" includes, but is not limited to, systems having only A, only B, only C, A and B together, A and C together, B and C together, and / or A, B, and C together). Those skilled in the art will further appreciate that virtually any disjunctive word and / or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibility of including one of the terms, either of the terms, or both terms. For example, the phrase "A or B" should be understood to include the possibility of "A" or "B" or "A and B." Additionally, as used herein, the term "any of" followed by a list of items and / or a list of categories of items is intended to include "any of," "any combination of," "any more than," and / or "any more than" of the items and / or categories of items, individually or in combination with other items and / or categories of items. Additionally, as used herein, the term "set" or "group" is intended to include any number of items, including zero. Additionally, as used herein, the term "number" is intended to include any number, including zero.

[0185] Furthermore, when features or aspects of the disclosure are described in terms of a Markush group, those skilled in the art will recognize that the disclosure is also described thereby in terms of any individual members or subgroups of members of the Markush group.

[0186] As will be appreciated by those skilled in the art, for all purposes, including in terms of providing a written description, all ranges disclosed herein encompass any possible subranges and combinations of subranges thereof. Any recited range can be readily recognized as fully descriptive and allowing the same range to be broken down into at least equal halves, thirds, quarters, fifths, tenths, etc. As a non-limiting example, each range described herein can be readily broken down into a lower third, a middle third, an upper third, etc. As will also be appreciated by those skilled in the art, all words such as "up to," "at least," "greater than," "less than," etc., refer to ranges that include the recited numbers and that can be further broken down into subranges as described above. Finally, as will be appreciated by those skilled in the art, ranges include individual elements. Thus, for example, a group having 1 to 3 cells refers to a group having 1, 2, or 3 cells. Similarly, a group having 1 to 5 cells refers to a group having 1, 2, 3, 4, or 5 cells, and so on.

[0187] Moreover, the claims should not be read as limited to the provided order or to the provided elements unless specifically so stated. Moreover, the use of the term "means for" in any claim is intended to invoke 35 U.S.C. 112, paragraph 6, or means-plus-function claim format, and no claim without the term "means for" is intended to do so.

[0188] A processor in association with software may be used to implement a radio frequency transceiver for use in a wireless transmit / receive unit (WTRU), user equipment (UE), terminal, base station, mobility management entity (MME) or evolved packet core (EPC), or any host computer. The WTRU may be used in conjunction with hardware and / or software implemented modules, such as, for example, a software defined radio (SDR), and may be implemented in other components, such as a camera, a video camera module, a video phone, a speaker phone, a vibration device, a speaker, a microphone, a television transceiver, a hands-free headset, a keyboard, a Bluetooth module, a frequency modulation (FM) radio unit, a near field communication (NFC) module, an LCD display unit, an organic light emitting diode (OLED) display unit, a digital music player, a media player, a video game player module, an Internet browser, and / or a wireless local area network (WLAN) or ultra-wideband (UWB) module.

[0189] Although the present invention has been described with respect to a communications system, it is contemplated that the system may be implemented in software on a microprocessor / general purpose computer (not shown). In particular embodiments, one or more of the functions of the various components may be implemented in software controlling a general purpose computer.

[0190] Moreover, although the invention is illustrated and described herein with reference to specific embodiments, the invention is not intended to be limited to the details shown, but rather various modifications can be made in the details within the scope of the claims and equivalents thereof without departing from the invention.

Claims

1. A first wireless transmit / receive unit (WTRU) comprising a processor and a memory, The processor and memory include receiving a resource information request from a second WTRU, the resource information request including an indication of a priority associated with a transmission performed by the second WTRU, an indication of a start and an end of a time window associated with the transmission performed by the second WTRU, and an indication of a number of sub-channels associated with the transmission performed by the second WTRU; determining a set of one or more resources based on the indicated priority, a start and end of the time window, and the number of sub-channels, the set of one or more resources including one or more resources that a first WTRU has determined to be usable by the second WTRU for the transmission performed by the second WTRU; determining assistance information resources for transmitting assistance information to the second WTRU, the assistance information including an indication of the set of one or more resources; transmitting a medium access control (MAC) control element (CE) or sidelink control information (SCI) including the assistance information to the second WTRU using the assistance information resource; configured to run, A first WTRU.

2. The first WTRU of claim 1 , wherein the assistance information includes an indication of a resource type.

3. The first WTRU of claim 2 , wherein the resource type indicates that one or more resources of the set of one or more resources are preferred resources.

4. The first WTRU of claim 1 , wherein the processor and memory are further configured to determine that one or more resources of the set of one or more resources are usable by the second WTRU based on sensing a set of candidate resources.

5. The first WTRU of claim 4 , wherein the sensing includes determining a reference signal received power (RSRP) measurement for one or more candidate resources of the set of candidate resources.

6. The first WTRU of claim 5 , wherein the sensing includes comparing the RSRP measurement to a threshold.

7. The first WTRU of claim 6 , wherein the processor and memory are configured to determine the threshold value based on an indication of priority included in the resource information request.

8. the priority indication included in the resource information request indicates a Layer 1 (L1) priority associated with the transmission performed by the second WTRU; The L1 priority is set to the highest priority; The processor and memory include determining a weighting factor based on the L1 priority; applying said weighting factors to the RSRP values; and determining the threshold value based on the weighting factors; The first WTRU of claim 7 , further configured to perform:

9. 1. A method performed by a first wireless transmit / receive unit (WTRU), comprising: receiving a resource information request from a second WTRU, the resource information request including an indication of a priority associated with a transmission performed by the second WTRU, an indication of a start and an end of a time window associated with the transmission performed by the second WTRU, and an indication of a number of sub-channels associated with the transmission performed by the second WTRU; determining a set of one or more resources based on the indicated priority, a start and end of the time window, and the number of sub-channels, the set of one or more resources including one or more resources that a first WTRU has determined to be usable by the second WTRU for the transmission performed by the second WTRU; determining assistance information resources for transmitting assistance information to the second WTRU, the assistance information including an indication of the set of one or more resources; transmitting a medium access control (MAC) control element (CE) or sidelink control information (SCI) including the assistance information to the second WTRU using the assistance information resource; The method includes:

10. The method of claim 9 , wherein the assistance information includes an indication of a resource type.

11. The method of claim 10 , wherein the resource type indicates that one or more resources in the set of one or more resources are preferred resources.

12. 10. The method of claim 9, further comprising determining that one or more resources of the set of one or more resources are usable by the second WTRU based on sensing a set of candidate resources.

13. The method of claim 12 , wherein the sensing comprises determining a reference signal received power (RSRP) measurement for one or more candidate resources of the set of candidate resources.

14. The method of claim 13 , wherein the sensing comprises comparing the RSRP measurement to a threshold.

15. The method of claim 14 , further comprising determining the threshold value based on an indication of the priority included in the resource information request.

16. the priority indication included in the resource information request indicates a Layer 1 (L1) priority associated with the transmission performed by the second WTRU; The L1 priority is set to the highest priority; The method comprises: determining a weighting factor based on the L1 priority; applying said weighting factors to the RSRP values; and determining the threshold value based on the weighting factors; 16. The method of claim 15, further comprising:

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