WO2020033704A1

WO2020033704A1 - Enhanced sidelink control transmission

Info

Publication number: WO2020033704A1
Application number: PCT/US2019/045729
Authority: WO
Inventors: Fengjun Xi; Chunxuan Ye; Kyle Jung-Lin Pan; Robert L. Olesen
Original assignee: Idac Holdings, Inc.
Priority date: 2018-08-08
Filing date: 2019-08-08
Publication date: 2020-02-13

Abstract

Systems, methods, and instrumentalities are disclosed for transmitting sidelink control information (SCI). A wireless transmit/receive unit (WTRU) may receive a first part of the SCI via a physical sidelink control channel (PSCCH). The first part of the SCI may include resource reservation information and data QoS information associated with the PSSCH. The WTRU may decode the first part of the SCI. The WTRU may determine whether the WTRU is interested in the PSSCH or intended to receive the PSSCH. If the WTRU determines that it is intended to receive the PSSCH, the WTRU may receive and decode the second part of the SCI. From the decoded second part of the SCI, the WTRU may obtain the decoding related information associated with the PSSCH. The WTRU may decode the PSSCH based on the decoding related information associated with the PSSCH and the resource reservation information associated with the PSSCH.

Description

ENHANCED SIDELINK CONTROL TRANSMISSION

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Patent Application Nos. 62/716,124 filed on August 08, 2018, 62/736,721 filed on September 26, 2018, and 62/826,429 filed on March 29, 2019, the contents of which are hereby incorporated by reference herein.

BACKGROUND

[0002] Use cases for fifth generation (5G) wireless communication systems may include Enhanced Mobile Broadband (eMBB), Massive Machine Type Communications (mMTC) and Ultra Reliable and Low latency Communications (URLLC). 5G also may contemplate transportation scenarios, e.g., vehicle-to- everything (V2X) use cases. Different use cases may focus on different requirements such as higher data rate, higher spectrum efficiency, low power and higher energy efficiency, lower latency and higher reliability. Current sidelink control information (SCI) transmission mechanisms for various transmission types may result in increased SCI decoding complexity.

SUMMARY

[0003] Systems, methods, and instrumentalities are disclosed for transmitting a sidelink control information (SCI). A receiving wireless transmit/receive unit (WTRU) (e.g., a vehicle-to-everything WTRU (V2X WTRU) may receive a first part of the SCI via a physical sidelink control channel (PSCCH). The first part of the SCI may be a broadcast transmission. The first part of the SCI may include resource reservation information associated with a PSSCH and data quality of service (QoS) information associated with the PSSCH. The WTRU may decode the first part of the SCI.

[0004] The WTRU may determine whether the WTRU is intended to receive the PSSCH. The WTRU may make the determination based on, for example, a parameter included in the decoded first part of the SCI. The WTRU may determine whether the PSSCH is for unicast or broadcast. For example, the WTRU may determine whether it is configured for a unicast transmission or a groupcast transmission. The WTRU intended to receive PSSCH may be referred to as the interested WTRU or the WTRU that is interested in the contents of the PSSCH. If the WTRU determines that it is intended to receive the PSSCH and the PSSCH is configured for a unicast transmission or a groupcast transmission, the WTRU may receive the second part of the SCI and decode the second part of the SCI. The second part of the SCI may be piggybacked on the PSSCH transmission. The second part of the SCI may be masked with a destination group ID. For example, in case of a unicast or a groupcast PSSCH transmission, the modulation of the second part of the SCI may be the modulation used for the PSSCH.

[0005] From the decoded second part of the SCI, the WTRU may obtain the decoding related information associated with the PSSCH. The WTRU may decode the PSSCH based on the decoding related information associated with the PSSCH obtained from decoding the second part of the SCI and the resource reservation information associated with the PSSCH obtained from the first part of the SCI.

[0006] If the WTRU determines that it is intended to receive the PSSCH and the PSSCH is configured for a broadcast transmission, the WTRU may decode the PSSCH based on the decoding related information associated with the PSSCH and the resource reservation information associated with the PSSCH obtained from the first part of the SCI. The second part of the SCI may not be masked. The decoding related information associated with the PSSCH may be obtained from the second part of the SCI, e.g., without decoding the second part of the SCI.

[0007] The WTRU may determine whether the WTRU has data to transmit on its PSSCH. If the WTRU has data to transmit on its PSSCH, the WTRU may perform resource selection based on, for example, the decoded first part of the SCI that includes the resource reservation information and the data QoS information associated with the PSSCH. The WTRU may perform the resource selection by excluding resources indicated by first part of the SCI. The WTRU may measure and store a physical sidelink shared channel-reference signal received power (PSSCH-RSRP) value and a sidelink receive strength signal indicator (S-RSSI) value for resource selection. The WTRU may further perform the resource selection based on the stored (PSSCH-RSRP) value and the S-RSSI value.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIG. 1A is a system diagram illustrating an example communications system in which one or more disclosed embodiments may be implemented.

[0009] FIG. 1 B 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 an embodiment.

[0010] FIG. 1C is a system diagram illustrating an example radio access network (RAN) and an example core network (CN) that may be used within the communications system illustrated in FIG. 1 A according to an embodiment.

[0011] FIG. 1 D is a system diagram illustrating a further example RAN and a further example CN that may be used within the communications system illustrated in FIG. 1A according to an embodiment. [0012] FIG. 2 illustrates exemplary adjacent and non-adjacent sub-channelization.

[0013] FIG. 3 illustrates various exemplary mechanisms for multiplexing physical sidelink control channel (PSCCH) and physical sidelink shared channel (PSSCH).

[0014] FIG. 4 illustrates an example modified allocation for non-adjacent and adjacent sub

channelization of PSCCFI and PSSCFI.

[0015] FIG. 5 illustrates a sub-channelization example for non-adjacent and adjacent PSCCFI and PSSCH.

[0016] FIG. 6 illustrates an example of separately and independently processing two parts of sidelink control information (SCI).

[0017] FIG. 7 illustrates an example of a WTRU receiving PSCCH and/or PSSCH information.

[0018] FIG. 8 illustrates an example of a WTRU receiving PSCCH for its resource selection and sending

PSSCH.

[0019] FIG. 9A illustrates an example of a WTRU receiving 2-stage PSCCH and/or PSSCH for an intended WTRU and efficient resource selection based on the first stage PSCCH.

[0020] FIG. 9B illustrates an example of a WTRU receiving PSCCH and resource selection based on the first part of the SCI

[0021] FIG. 10 illustrates an example of separating the new radio (NR) SCI contents to three parts, based on the type of information, and processing each part of SCI payload.

[0022] FIG. 11 illustrates an example where the NR SCI payload is partitioned to two parts.

[0023] FIG. 12 illustrates an example of a WTRU separately processing two parts of SCI for groupcast or unicast sidelink data transmissions.

[0024] FIG. 13 illustrates an example of a WTRU receiving PSCCH and PSSCH for broadcast, groupcast, or unicast sidelink data transmissions.

[0025] FIG. 14 illustrates an example of a WTRU receiving 2-stage PSCCH and/or PSSCH for intended WTRU and efficient resource selection based on the first stage PSCCH for carrier aggregation.

[0026] FIG. 15 shows an example of a receiver WTRU decoding SCI and PSSCH.

[0027] FIG. 16 shows another example of a receiver WTRU decoding SCI and PSSCH.

[0028] FIG. 17 shows another example of a receiver WTRU decoding SCI and PSSCH.

[0029] FIG. 18 illustrates an example of resource element mapping for PSSCH carrying SCI part 2 in Mechanism 3 of the PSCCH/PSSCH multiplexing. [0030] FIG. 19 illustrates another example of resource element mapping for PSSCH carrying SCI part 2 in mechanism 3 of PSCCH/PSSCH multiplexing.

[0031] FIG. 20 illustrates an example of resource element mapping for PSSCH carrying SCI part 2 in mechanism 2/1 B of PSCCH/PSSCH multiplexing.

[0032] FIG. 21 illustrates another example of resource element mapping for PSSCH carrying SCI part 2 in mechanism 2/1 B of PSCCH/PSSCH multiplexing.

[0033] FIG. 22 illustrates an example of a WTRU decoding SCI in case of a dynamic number of control OFDM symbols.

[0034] FIG. 23 illustrates an exemplary frame structure of PSCCFI and PSSCH in Discrete Fourier Transform (DFT) spread Orthogonal Frequency Division Multiplexing (OFDM) (DFT-s-OFDM).

[0035] FIG. 24 illustrates an exemplary frame structure of PSCCFI and PSSCH in cyclic prefix

Orthogonal Frequency Division Multiplexing (CP-OFDM).

[0036] FIG. 25 illustrates an example table comprising example symbol durations for various sub-carrier spacings.

[0037] FIG. 26 illustrates an exemplary frame structure of PSCCFI and PSSCH for sub carrier spacing (SCS I) of 120 kHz.

[0038] FIG. 27 illustrates an exemplary frame structure of PSCCH and PSSCH for SCS of 240 kHz.

DETAILED DESCRIPTION

[0039] FIG. 1A is a diagram illustrating an example communications system 100 in which one or more disclosed embodiments may be implemented. The communications system 100 may be a multiple access system that provides content, such as voice, data, video, messaging, broadcast, etc., to multiple wireless users. The communications system 100 may enable multiple wireless users to access such content through the sharing of system resources, including wireless bandwidth. For example, the communications systems 100 may employ one or more channel access methods, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single-carrier FDMA (SC-FDMA), zero-tail unique-word DFT-Spread OFDM (ZT UW DTS-s OFDM), unique word OFDM (UW-OFDM), resource block-filtered OFDM, filter bank multicarrier (FBMC), and the like.

[0040] As shown in FIG. 1A, the communications system 100 may include wireless transmit/receive units (WTRUs) 102a, 102b, 102c, 102d, a RAN 104/113, a ON 106/115, a public switched telephone network (PSTN) 108, the Internet 110, and other networks 112, though it will be appreciated that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and/or network elements. Each of the WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and/or communicate in a wireless environment. By way of example, the WTRUs 102a, 102b, 102c, 102d, any of which may be referred to as a "station” and/or a "STA”, may be configured to transmit and/or receive wireless signals and may include a user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a subscription-based unit, a pager, a cellular telephone, a personal digital assistant (PDA), a smartphone, a laptop, a netbook, a personal computer, a wireless sensor, a hotspot or Mi-Fi device, an Internet of Things (loT) device, a watch or other wearable, a head-mounted display (HMD), a vehicle, a drone, a medical device and applications (e.g., remote surgery), an industrial device and applications (e.g., a robot and/or other wireless devices operating in an industrial and/or an automated processing chain contexts), a consumer electronics device, a device operating on commercial and/or industrial wireless networks, and the like. Any of the WTRUs 102a, 102b, 102c and 102d may be interchangeably referred to as a UE.

[0041] The communications systems 100 may also include a base station 114a and/or a base station 1 14b. Each of the base stations 1 14a, 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 1 10, and/or the other networks 112. By way of example, the base stations 1 14a, 114b may be a base transceiver station (BTS), a Node-B, an eNode B, a Home Node B, a Home eNode B, a gNB, a NR NodeB, a site controller, an access point (AP), a wireless router, and the like. While the base stations 114a, 114b are each depicted as a single element, it will be appreciated that the base stations 1 14a, 1 14b may include any number of interconnected base stations and/or network elements.

[0042] The base station 114a may be part of the RAN 104/1 13, which may also include other base stations and/or network elements (not shown), such as a base station controller (BSC), a radio network controller (RNC), relay nodes, etc. The base station 114a and/or 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 in licensed spectrum, unlicensed spectrum, or a combination of licensed and unlicensed spectrum. A cell may provide coverage for a wireless service to a specific geographical area that may be relatively fixed or that may change over time. The cell may further be divided into cell sectors. For example, the cell associated with the base station 114a may be divided into three sectors. Thus, in one embodiment, the base station 114a may include three transceivers, i.e., one for each sector of the cell. In an embodiment, the base station 1 14a may employ multiple-input multiple output (MIMO) technology and may utilize multiple transceivers for each sector of the cell. For example, beamforming may be used to transmit and/or receive signals in desired spatial directions.

[0043] 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).

[0044] More specifically, as noted above, the communications system 100 may be a multiple access system and may employ one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and the like. For example, the base station 114a in the RAN 104/113 and the WTRUs 102a, 102b, 102c may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may establish the air interface 1 15/1 16/1 17 using wideband CDMA (WCDMA). WCDMA may include communication protocols such as High-Speed Packet Access (FI SPA) and/or Evolved HSPA (FISPA+). HSPA may include High-Speed Downlink (DL) Packet Access (FISDPA) and/or High-Speed UL Packet Access (FISUPA).

[0045] In an 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).

[0046] In an 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 1 16 using New Radio (NR).

[0047] In an 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, for instance using dual connectivity (DC) principles. Thus, the air interface utilized by WTRUs 102a, 102b, 102c may be characterized by multiple types of radio access technologies and/or transmissions sent to/from multiple types of base stations (e.g., a eNB and a gNB).

[0048] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement radio technologies such as IEEE 802.11 (i.e., Wireless Fidelity (WiFi), IEEE 802.16 (i.e., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile communications (GSM), Enhanced Data rates for GSM Evolution (EDGE), GSM EDGE (GERAN), and the like. [0049] The base station 114b in FIG. 1 A may be a wireless router, Home Node B, Home eNode B, or access point, for example, and may utilize any suitable RAT for facilitating wireless connectivity in a localized area, such as a place of business, a home, a vehicle, a campus, an industrial facility, an air corridor (e.g., for use by drones), a roadway, and the like. 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 an embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.15 to establish a wireless personal area network (WPAN). In yet another embodiment, the base station 114b and the WTRUs 102c, 102d may utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR etc.) to establish a picocell or femtocell. 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 be required to access the Internet 110 via the CN 106/115.

[0050] The RAN 104/113 may be in communication with the CN 106/115, which may be any type of network configured to provide voice, data, applications, and/or voice over internet protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. The data may have varying quality of service (QoS) requirements, such as differing throughput requirements, latency requirements, error tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, and the like. The CN 106/115 may provide call control, billing services, mobile location-based services, pre-paid calling, Internet connectivity, video distribution, etc., and/or perform high-level security functions, such as user authentication. Although not shown in FIG. 1A, it will be appreciated that the RAN 104/113 and/or the CN 106/115 may be in direct or indirect communication with other RANs that employ 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 be utilizing a NR radio technology, the CN 106/115 may also be in communication with another RAN (not shown) employing a GSM, UMTS, CDMA 2000, WiMAX, E-UTRA, or WiFi radio technology.

[0051] The CN 106/115 may also serve as a gateway for the WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the Internet 110, and/or the other networks 112. The PSTN 108 may include circuit- switched telephone networks that provide 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) in the TCP/IP internet protocol suite. The networks 112 may include wired and/or wireless communications networks owned and/or operated by other service providers. For example, the networks 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. [0052] 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. 1 A may be configured to communicate with the base station 114a, which may employ a cellular-based radio technology, and with the base station 114b, which may employ an IEEE 802 radio technology.

[0053] FIG. 1 B is a system diagram illustrating an example WTRU 102. As shown in FIG. 1 B, the WTRU 102 may include a processor 118, a transceiver 120, a transmit/receive element 122, a speaker/microphone 124, a keypad 126, a display/touchpad 128, non-removable memory 130, removable memory 132, a power source 134, a global positioning system (GPS) chipset 136, and/or other peripherals 138, among others. It will be appreciated that the WTRU 102 may include any sub-combination of the foregoing elements while remaining consistent with an embodiment.

[0054] The processor 118 may be a general purpose processor, a special purpose processor, a conventional processor, a digital signal processor (DSP), a plurality of microprocessors, one or more microprocessors in association with a DSP core, a controller, a microcontroller, Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs) circuits, any other type of integrated circuit (IC), a state machine, and the like. The processor 118 may perform signal coding, data processing, power control, input/output processing, and/or any other functionality that enables the WTRU 102 to operate in a wireless environment. The processor 118 may be coupled to the transceiver 120, which may be coupled to the transmit/receive element 122. While FIG. 1 B depicts the processor 118 and the transceiver 120 as separate components, it will be appreciated that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip.

[0055] The transmit/receive element 122 may be configured to transmit signals to, or receive signals from, a base station (e.g., the 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 an embodiment, the transmit/receive element 122 may be an emitter/detector configured to transmit and/or receive IR, UV, or visible light signals, for example. In yet another embodiment, the transmit/receive element 122 may be configured to transmit and/or receive both RF and light signals. It will be appreciated that the transmit/receive element 122 may be configured to transmit and/or receive any combination of wireless signals.

[0056] Although the transmit/receive element 122 is depicted in FIG. 1 B as a single element, the WTRU 102 may include any number of transmit/receive elements 122. More specifically, the WTRU 102 may employ MIMO technology. Thus, in one embodiment, the WTRU 102 may include two or more transmit/receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals over the air interface 116.

[0057] The transceiver 120 may be configured to modulate the signals that are to be transmitted by the transmit/receive element 122 and to demodulate the signals that are received by the transmit/receive element 122. As noted above, the WTRU 102 may have multi-mode capabilities. Thus, the transceiver 120 may include multiple transceivers for enabling the WTRU 102 to communicate via multiple RATs, such as NR and IEEE 802.11 , for example.

[0058] The processor 118 of the WTRU 102 may be coupled to, and may receive user input data from, the speaker/microphone 124, the keypad 126, and/or the display/touchpad 128 (e.g., a liquid crystal display (LCD) display unit or 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. In addition, the processor 118 may access information from, and store data in, any type of suitable memory, such as the non-removable memory 130 and/or the 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, and the like. In other embodiments, the processor 118 may access information from, and store data in, memory that is not physically located on the WTRU 102, such as on a server or a home computer (not shown).

[0059] The processor 118 may receive power from the power source 134, and may be configured to distribute and/or control the power to the other components in the WTRU 102. The power source 134 may be any suitable device for powering the WTRU 102. For example, the power source 134 may include one or more dry cell batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, and the like.

[0060] The processor 118 may also be coupled to the GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) regarding the current location of the WTRU 102.

In addition to, or in lieu of, the 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 the signals being received from two or more nearby base stations. It will be appreciated that the WTRU 102 may acquire location information by way of any suitable location- determination method while remaining consistent with an embodiment.

[0061] The processor 118 may further be coupled to other peripherals 138, which may include one or more software and/or hardware modules that provide additional features, functionality and/or wired or wireless connectivity. For example, the peripherals 138 may include an accelerometer, an e-compass, a satellite transceiver, a digital camera (for photographs and/or video), 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, the sensors 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.

[0062] The WTRU 102 may include a full duplex radio for which transmission and reception of some or all of the signals (e.g., associated with particular subframes for both the UL (e.g., for transmission) and downlink (e.g., for reception) may be concurrent and/or simultaneous. The full duplex radio may include an interference management unit to reduce and or substantially eliminate self-interference via either hardware (e.g., a choke) or signal processing via a processor (e.g., a separate processor (not shown) or via processor 118). In an embodiment, the WRTU 102 may include a half-duplex radio for which transmission and reception of some or all of the signals (e.g., associated with particular subframes for either the UL (e.g., for transmission) or the downlink (e.g., for reception)).

[0063] FIG. 1C is a system diagram illustrating the RAN 104 and the CN 106 according to an embodiment. As noted above, the RAN 104 may employ an E-UTRA radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 104 may also be in communication with the CN 106.

[0064] The RAN 104 may include eNode-Bs 160a, 160b, 160c, though it will be appreciated 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 one embodiment, the eNode-Bs 160a, 160b, 160c may implement MIMO technology. Thus, the eNode-B 160a, for example, may use multiple antennas to transmit wireless signals to, and/or receive wireless signals from, the WTRU 102a.

[0065] 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, and the like. As shown in FIG. 1C, the eNode-Bs 160a, 160b, 160c may communicate with one another over an X2 interface.

[0066] The CN 106 shown in FIG. 1C may include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (or PGW) 166. While each of the foregoing elements are depicted as part of the CN 106, it will be appreciated that any of these elements may be owned and/or operated by an entity other than the CN operator.

[0067] The MME 162 may be connected to each of the eNode-Bs 162a, 162b, 162c in the RAN 104 via an S1 interface and may serve as a control node. For example, the MME 162 may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, bearer activation/deactivation, selecting a particular serving gateway during an initial attach of the WTRUs 102a, 102b, 102c, and the like. 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.

[0068] The SGW 164 may be connected to each of the eNode Bs 160a, 160b, 160c in the RAN 104 via the S1 interface. The SGW 164 may generally route and forward user data packets to/from the WTRUs 102a, 102b, 102c. The SGW 164 may perform other functions, such as anchoring user planes during inter- eNode B handovers, triggering paging when DL data is available for the WTRUs 102a, 102b, 102c, managing and storing contexts of the WTRUs 102a, 102b, 102c, and the like.

[0069] The SGW 164 may be connected to the 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.

[0070] 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 may 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. In addition, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to the other networks 112, which may include other wired and/or wireless networks that are owned and/or operated by other service providers.

[0071] Although the WTRU is described in FIGS. 1 A-1 D as a wireless terminal, it is contemplated that in certain representative embodiments that such a terminal may use (e.g., temporarily or permanently) wired communication interfaces with the communication network.

[0072] In representative embodiments, the other network 112 may be a WLAN.

[0073] A WLAN in Infrastructure Basic Service Set (BSS) mode may have an Access Point (AP) for the BSS and one or more stations (STAs) associated with the AP. The AP may have an access or an interface to a Distribution System (DS) or another type of wired/wireless network that carries traffic in to and/or out of the BSS. Traffic to STAs that originates from outside the BSS may arrive through the AP and may be delivered to the STAs. Traffic originating from STAs to destinations outside the BSS may be sent to the AP to be delivered to respective destinations. Traffic between STAs within the BSS may be sent through the AP, for example, where the source STA may send traffic to the AP and the AP may deliver the traffic to the destination STA. The traffic between STAs within a BSS may be considered and/or referred to as peer-to- peer traffic. The peer-to-peer traffic may be sent between (e.g., directly between) the source and destination STAs with a direct link setup (DLS). In certain representative embodiments, the DLS may use an 802.11e DLS or an 802.11z tunneled DLS (TDLS). A WLAN using an Independent BSS (IBSS) mode may not have an AP, and the STAs (e.g., all of the STAs) within or using the IBSS may communicate directly with each other. The IBSS mode of communication may sometimes be referred to herein as an "ad- hoc” mode of communication.

[0074] When using the 802.11 ac infrastructure mode of operation or a similar mode of operations, the AP may transmit a beacon on a fixed channel, such as a primary channel. The primary channel may be a fixed width (e.g., 20 MHz wide bandwidth) or a dynamically set width via signaling. The primary channel may be the operating channel of the BSS and may be used by the STAs to establish a connection with the AP. In certain representative embodiments, Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) may be implemented, for example in in 802.11 systems. For CSMA/CA, the STAs (e.g., every STA), including the AP, may sense the primary channel. If the primary channel is sensed/detected and/or determined to be busy by a particular STA, the particular STA may back off. One STA (e.g., only one station) may transmit at any given time in a given BSS.

[0075] High Throughput (HT) STAs may use a 40 MHz wide channel for communication, for example, via a combination of the primary 20 MHz channel with an adjacent or nonadjacent 20 MHz channel to form a 40 MHz wide channel.

[0076] Very High Throughput (VHT) STAs may support 20MHz, 40 MHz, 80 MHz, and/or 160 MHz wide channels. The 40 MHz, and/or 80 MHz, channels may be formed by combining contiguous 20 MHz channels. A 160 MHz channel may be formed by combining 8 contiguous 20 MHz channels, or by combining two non-contiguous 80 MHz channels, which may be referred to as an 80+80 configuration. For the 80+80 configuration, the data, after channel encoding, may be passed through a segment parser that may divide the data into two streams. Inverse Fast Fourier Transform (IFFT) processing, and time domain processing, may be done on each stream separately. The streams may be mapped on to the two 80 MHz channels, and the data may be transmitted by a transmitting STA. At the receiver of the receiving STA, the above described operation for the 80+80 configuration may be reversed, and the combined data may be sent to the Medium Access Control (MAC).

[0077] Sub 1 GHz modes of operation are supported by 802.11 af and 802.11 ah. The channel operating bandwidths, and carriers, are reduced in 802.11 af and 802.11 ah relative to those used in 802.11 h, and 802.11 ac. 802.11 af supports 5 MHz, 10 MHz and 20 MHz bandwidths in the TV White Space (TVWS) spectrum, and 802.11 ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths using non- TVWS spectrum. According to a representative embodiment, 802.11 ah may support Meter Type

Control/Machine-Type Communications, such as MTC devices in a macro coverage area. MTC devices may have certain capabilities, for example, limited capabilities including support for (e.g., only support for) certain and/or limited bandwidths. The MTC devices may include a battery with a battery life above a threshold (e.g., to maintain a very long battery life).

[0078] WLAN systems, which may support multiple channels, and channel bandwidths, such as 802.11h, 802.11 ac, 802.11 af, and 802.11 ah, include a channel which may be designated as the primary channel. The primary channel may have a bandwidth equal to the largest common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel may be set and/or limited by a STA, from among all STAs in operating in a BSS, which supports the smallest bandwidth operating mode.

In the example of 802.11 ah, the primary channel may be 1 MHz wide for STAs (e.g., MTC type devices) that support (e.g., only support) a 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 status of the primary channel. If the primary channel is busy, for example, due to a STA (which supports only a 1 MHz operating mode), transmitting to the AP, the entire available frequency bands may be considered busy even though a majority of the frequency bands remains idle and may be available.

[0079] In the United States, the available frequency bands, which may be used by 802.11 ah, are from 902 MHz to 928 MHz. In Korea, the available frequency bands are from 917.5 MHz to 923.5 MHz. In Japan, the available frequency bands are from 916.5 MHz to 927.5 MHz. The total bandwidth available for 802.11 ah is 6 MHz to 26 MHz depending on the country code.

[0080] FIG. 1 D is a system diagram illustrating the RAN 113 and the CN 115 according to an embodiment. As noted above, the RAN 113 may employ an NR radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 113 may also be in communication with the CN 115.

[0081] The RAN 113 may include gNBs 180a, 180b, 180c, though it will be appreciated 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 one embodiment, the gNBs 180a, 180b, 180c may implement MIMO technology. For example, gNBs 180a, 108b may utilize beamforming to transmit signals to and/or receive signals from the gNBs 180a, 180b, 180c. Thus, the gNB 180a, for example, may use multiple antennas to transmit wireless signals to, and/or receive wireless signals from, the WTRU 102a. In an embodiment, the gNBs 180a, 180b, 180c may implement carrier aggregation technology. For example, the gNB 180a may transmit multiple component carriers to the WTRU 102a (not shown). A subset of these component carriers may be on unlicensed spectrum while the remaining component carriers may be on licensed spectrum. In an embodiment, the gNBs 180a, 180b, 180c may implement Coordinated Multi-Point (CoMP) technology. For example, WTRU 102a may receive coordinated transmissions from gNB 180a and gNB 180b (and/or gNB 180c).

[0082] The WTRUs 102a, 102b, 102c may communicate with 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 gNBs 180a, 180b, 180c using subframe or transmission time intervals (TTIs) of various or scalable lengths (e.g., containing varying number of OFDM symbols and/or lasting varying lengths of absolute time).

[0083] 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 the standalone configuration, WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c without also accessing other RANs (e.g., such as eNode-Bs 160a, 160b, 160c). In the standalone configuration, WTRUs 102a, 102b, 102c may utilize one or more of gNBs 180a, 180b, 180c as a mobility anchor point. In the standalone configuration, WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using signals in an unlicensed band. In a non-standalone configuration WTRUs 102a, 102b, 102c may communicate with/connect to gNBs 180a, 180b, 180c while also communicating with/connecting to another RAN such as eNode-Bs 160a, 160b, 160c. For example, 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 the non-standalone configuration, eNode-Bs 160a, 160b, 160c may serve as a mobility anchor for WTRUs 102a, 102b, 102c and gNBs 180a, 180b, 180c may provide additional coverage and/or throughput for servicing WTRUs 102a, 102b, 102c.

[0084] 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 of network slicing, dual connectivity, interworking between NR and E- UTRA, routing of user plane data towards User Plane Function (UPF) 184a, 184b, routing of control plane information towards Access and Mobility Management Function (AMF) 182a, 182b and the like. As shown in FIG. 1 D, the gNBs 180a, 180b, 180c may communicate with one another over an Xn interface. [0085] The CN 115 shown in FIG. 1 D may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one Session Management Function (SMF) 183a, 183b, and possibly a Data Network (DN) 185a, 185b. While each of the foregoing elements are depicted as part of the CN 115, it will be appreciated that any of these elements may be owned and/or operated by an entity other than the CN operator.

[0086] The AMF 182a, 182b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 1 13 via an N2 interface and may serve as a control node. For example, the AMF 182a, 182b may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, support for network slicing (e.g., handling of different PDU sessions with different requirements), selecting a particular SMF 183a, 183b, management of the registration area, termination of NAS signaling, mobility management, and the like. Network slicing may be used by the AMF 182a, 182b in order to customize CN support for WTRUs 102a, 102b, 102c based on the types of services being utilized 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 1 13 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.

[0087] The SMF 183a, 183b may be connected to an AMF 182a, 182b in the CN 115 via an N1 1 interface. The SMF 183a, 183b may also be connected to a UPF 184a, 184b in the CN 115 via an N4 interface. The SMF 183a, 183b may select and control the UPF 184a, 184b and configure the routing of traffic through the UPF 184a, 184b. The SMF 183a, 183b may perform other functions, such as managing and allocating UE IP address, managing PDU sessions, controlling policy enforcement and QoS, providing downlink data notifications, and the like. A PDU session type may be IP-based, non-IP based, Ethernet- based, and the like.

[0088] The UPF 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 1 10, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices. The UPF 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, and the like.

[0089] The CN 115 may facilitate communications with other networks. For example, the CN 1 15 may include, or may communicate with, an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that serves as an interface between the CN 1 15 and the PSTN 108. In addition, the CN 115 may provide the WTRUs 102a, 102b, 102c with access to the other networks 112, which may include other wired and/or wireless networks that are owned and/or operated by other service providers. In one embodiment, the WTRUs 102a, 102b, 102c may be connected to a local Data Network (DN) 185a, 185b through the UPF 184a, 184b via the N3 interface to the UPF 184a, 184b and an N6 interface between the UPF 184a, 184b and the DN 185a, 185b.

[0090] In view of Figures 1A-1 D, and the corresponding description of Figures 1A-1 D, one or more, or all, of the functions described herein with regard to one or more of: WTRU 102a-d, Base Station 114a-b, eNode-B 160a-c, MME 162, SGW 164, PGW 166, gNB 180a-c, AMF 182a-b, UPF 184a-b, SMF 183a-b, DN 185a-b, and/or any other device(s) described herein, may be performed by one or more emulation devices (not shown). The emulation devices may be one or more devices configured to emulate one or more, or all, of the functions described herein. For example, the emulation devices may be used to test other devices and/or to simulate network and/or WTRU functions.

[0091] The emulation devices may be designed to implement one or more tests of other devices in a lab environment and/or in an operator network environment. For example, the one or more emulation devices may perform the one or more, or all, functions while being fully or partially implemented and/or deployed as part of a wired and/or wireless communication network in order to test other devices within the communication network. The one or more emulation devices may perform the one or more, or all, functions while being temporarily implemented/deployed as part of a wired and/or wireless communication network. The emulation device may be directly coupled to another device for purposes of testing and/or may performing testing using over-the-air wireless communications.

[0092] The one or more emulation devices may perform the one or more, including all, functions while not being implemented/deployed as part of a wired and/or wireless communication network. For example, the emulation devices may be utilized in a testing scenario in a testing laboratory and/or a non-deployed (e.g., testing) wired and/or wireless communication network in order to implement testing of one or more components. The one or more emulation devices may be test equipment. Direct RF coupling and/or wireless communications via RF circuitry (e.g., which may include one or more antennas) may be used by the emulation devices to transmit and/or receive data.

[0093] Control information may be used for vehicle-to-everything (V2X) communications. For example, control information may be communicated via a downlink control information (DCI) (e.g., DCI Format 5A) and/or a sidelink control information (SCI) (e.g., SCI format 1). The DCI may be communicated via a physical downlink control channel (PDCCH) while the SCI may be communicated via a physical sidelink control channel. [0094] The DCI format 5A may be used for the scheduling of PSCCH. One or more SCI format 1 fields may be used for the scheduling of physical sidelink shared channel (PSSCH). The payload of DCI format 5A may include one or more of the following: carrier indicator (e.g., 3 bits); lowest index of the subchannel allocation to the initial transmission (e.g., [log₂(A¾_channel)^"| bits); SCI format 1 fields, such as frequency resource location of initial transmission and retransmission and/or time gap between initial transmission and retransmission; or SL index (e.g., 2 bits), where, for example, the SL index field is present for cases with TDD operation with uplink-downlink configuration 0-6. When the format 5A CRC is scrambled with a sidelink semi-persistent scheduling V-RNTI (SL-SPS-V-RNTI), one or more of the following fields may be present: SL SPS configuration index (e.g., 3 bits); or activation/release indication (e.g., 1 bit).

[0095] If the number of information bits in format 5A that are mapped onto a given search space is less than the payload size of format 0 that are mapped onto the same search space, zeros may be appended to format 5A until the payload size equals that of format 0 including padding bits appended to format 0. If the format 5A CRC is scrambled by SL-V-RNTI and if the number of information bits in format 5A that are mapped onto a given search space is less than the payload size of format 5A (e.g., with CRC scrambled by SL-SPS-V-RNTI) that are mapped onto the same search space and format 0 is not defined on the same search space, zeros may be appended to format 5A until the payload size equals that of format 5A with CRC scrambled by SL-SPS-V-RNTI.

[0096] The payload of SCI format 1 may include one or more of the following: Priority (e.g., 3 bits); Resource reservation (e.g., 4 bits); Frequency resource location of initial transmission and retransmission

(e.g, [log₂ (L^₅¾_0ΐ1£ihh6ΐ(A"₅¾_{0ΐ1£11ih6ΐ} + 1) / 2)] ); Time gap between initial transmission and retransmission (e.g, 4 bits); Modulation and Coding scheme (e.g, 5 bits); Retransmission index (e.g, 1 bit); or reserved information bits may be added until the size of SCI format 1 is equal to 32 bits, reserved bits may be set to zero.

[0097] In LTE V2X (LTE-V) sidelink, each resource of PSCCH and PSSCH may occupy a single sub- frame in the time domain and each PSCCH may occupy 2 RBs in the frequency domain. There may be two different PSCCH and PSSCH structures in each LTE V2X communication resource pool. In the first structure, PSCCH and PSSCH may be adjacent in the frequency domain. In the second structure, PSCCH and PSSCH may not be non-adjacent in the frequency domain. This information may be configured, e.g, using an information element (IE) SL-CommResourcePoolV2X, with the Boolean parameter

“adjacencyPSCCH-PSSCH-r14”.

[0098] FIG. 2 illustrates an example of adjacent and non-adjacent PSCCH and PSSCH sub channelization (e.g, LTE-V adjacent and non-adjacent sub-channelization). In these schemes, the SCI resource pools may be distributed with the data resource pools, or the SCI and data resource pools may be separated. LTE-V may utilize single carrier frequency division multiple access (SC-FDMA) (or Discrete Fourier Transform spread Orthogonal Frequency Division Multiplexing (DFT-s-OFDM)) for the transmission waveform. Since the SC-FDMA is a single carrier waveform this may impose some constraints on the choice of the resource allocation.

[0099] Communications over sidelink may use communication periods that may be periodic in the time domain. A sidelink period (e.g., each sidelink period) may include instances of the PSCCFI and the PSSCFI. The PSCCFI may carry control information and PSSCFI may carry data. WTRUs may be configured (e.g., pre-configured) by the network to operate with a periodic duration, PSCCFI configuration, and PSSCFI configuration. The WTRUs may use the configurations, for example, to operate autonomously when they are out of coverage, instead of relying on configuration information from an eNodeB. In LTE WTRUs with data to send may select random resources from a PSCCFI resource pool. The WTRUs may send a control message (e.g., using SCI). The control message may be used by potential receivers to identify those resources. This may be referred to as Mode 4 transmission. The WTRUs used for Mode 4 transmission may be referred to as Mode 4 WTRUs.

[0100] NR may use several mechanisms for multiplexing PSCCFI and PSSCFI. FIG. 3 illustrates various exemplary multiplexing mechanisms. In a first mechanism (Mechanism 1A and Mechanism 1 B) and as illustrated in FIG. 3, PSCCFI and the associated PSSCFI may be transmitted using non-overlapping time resources. In a first sub-mechanism 1 A, the frequency resources used by the two channels may be identical. In a second sub-mechanism 1 B, the frequency resources used by the two channels may be different.

[0101] According to a second mechanism (Mechanism 2), PSCCFI and the associated PSSCFI may be transmitted using non-overlapping frequency resources in the all-the-time resources used for transmission. The time resources used by the two channels are the same.

[0102] According to a third mechanism (Mechanism 3), a part of PSCCFI and the associated PSSCFI may be transmitted using overlapping time resources in non-overlapping frequency resources. Another part of the associated PSSCFI and/or another part of the PSCCFI may be transmitted using non-overlapping time resources.

[0103] Various use cases may be available for applications pertaining to V2X for which high reliable sidelink data transmissions are desired. For example, for use cases related to the emergency trajectory alignment between WTRUs supporting V2X applications and remote driving applications the desired reliability may have a requirement as high as 99.999%. [0104] In case of LTE for vehicles (LTE-V) Mode 4 transmissions, the resources used for transmission may be randomly selected. Such a random selection of resources may result in an increase in collisions between WTRUs that may simultaneously transmit. Reliable data transmissions may rely on the correct transmission of sidelink control information (SCI), e.g., this information may provide for the correct reception of a transport block. One or more implementations provided herein may enhance the reliability of SCI transmissions.

[0105] NR V2X use cases may be required to support different latencies. Some of the NR V2X use cases may require low latency transmissions. For example, the lowest latency for vehicle platoon, advanced driving, extended sensors, and remote driving may be approximately 10ms, 3ms, 3ms and 5ms respectively. The low latency in PSSCH decoding may depend on the low latency of PSCCFI decoding. One or more implementations provided herein may reduce the complexity and/or the latency of the SCI decoding. A WTRU (e.g., a Mode 4 WTRU) while performing resource selection may decode the SCIs from neighbour WTRUs. Reducing the decoding complexity and/or latency of SCI may allow the WTRU to be more efficient, e.g., in its sensing and resource selection.

[0106] Resource allocation for PSCCFI may be provided as described herein. The SCI (e.g., in case of LTE-V) may be carried on the PSCCFI, The PSCCFI may occupy two consecutive resource blocks (RB)s. A WTRU (e.g., an LTE-V WTRU) may use a single carrier waveform SC-FDMA for transmissions. Sub channelization schemes for PSCCFI may be provided, e.g., considering that NR V2X may use SC-FDMA (or DFT-s-OFDM) or OFDM (or cyclic prefix orthogonal frequency division multiplexing (CP-OFDM)) for the transmission carrier waveform. NR V2X sidelink may be scheduled and/or transmitted based on slot-based and/or non-slot based (e.g., mini-slot or sub-slot or symbol-based) NR SL frame structure. The slot-based and/or the non-slot based frame structure may be utilized to meet various requirements (e.g., latency requirement) for different V2X services and use cases.

[0107] In LTE-V, the PSCCFI may occupy two consecutive RBs, and a sub-frame may be 1 ms long, e.g., a sub-frame as illustrated in FIG. 2. This may be similar to the transmission time interval (TTI).

[0108] Sub-channelization schemes may be provided (e.g., which may enable improved reliability of PSCCFI transmissions). The sub-channelization schemes may be utilized in part due to the opportunity to leverage the OFDM waveform. Various examples may be provided for determining the location of RBs utilized for PSCCFI transmission.

[0109] In various examples, the PSCCFI and PSSCH may be in the same slot, sub-slot, mini-slot, non slot, or other time granularities (e.g., one or more symbols). The PSCCFI and PSSCH may be multiplexed using Frequency Division Multiplexing (FDM), Time Division Multiplexing (TDM), Spatial Division

Multiplexing (SDM), and/or combinations thereof (e.g., where SC-FDMA (or DFT-s-OFDM) and OFDM (or CP-OFDM) may be utilized as possible waveforms). The combination of different multiplexing schemes between PSCCH and PSSCH may be allocated in the same or different resource pools. The multiplexing scheme used may depend on one or more factors or parameters, for example, including one or more of the following: the transport block location (e.g., timeslot), the geographic location, Doppler, WTRU density, transmission mode (e.g., similar to Mode 3 or 4 in LTE-V), or latency requirement (e.g., selection window).

[0110] One or more implementations may be provided related to allocation for sub-channelization of PSCCH, e.g., with 2 RBs. FIG. 4 illustrates an exemplary modified allocation for non-adjacent and adjacent sub-channelization of PSCCH and PSSCH. As illustrated in FIG. 4, PSCCH may occupy 2 RBs. For these implementations, in an example, a single RB may be allocated for use to a single PSCCH. In another example, two or more RBs may be allocated for use to a single PSCCH.

[0111] FIG. 4 (left sub-figure) illustrates an example of a non-adjacent scheme. As illustrated in FIG. 4 (left sub-figure), RBs allocated to a single PSCCH may be distributed over a PSCCH resource pool (e.g., an entire PSCCH resource pool). For example, assuming the PSCCH resource pool occupies X consecutive RBs to support PSCCH channels, the first PSCCH channel may use the first RB, and the

+ l)-th RB. The second PSCCH channel may use the second RB and the + 2)-th RB, etc. An

illustrated in FIG. 4, in this case, the PSCCH resource m may be the set of two resource blocks with the physical resource block number n_PRB = n_PSCCHstart + 2 * m + j * N_subCH = 0,1 · The n_PSCCHstart may be predefined, or signalled, as the starting RB index of the PSCCH pool. N_subCH ^maY be predefined, or signalled, as the total number of sub-channels in the corresponding resource pool.

[0112] FIG. 4 (right sub-figure) illustrates an example of an adjacent PSCCH and PSSCH scheme. In an adjacent PSCCH and PSSCH scheme, for example, pairs of RBs may be allocated to the edges of the PSSCH resource pools. For example, a PSSCH resource may occupy X consecutive RBs, where a first RB index may be UL . The PSCCH may (e.g., next) be allocated to a V-th RB and (Y + )-th RB. As illustrated in FIG. 4 (right sub-figure), a PSCCH resource m may be a set of two resource blocks with the physical RB number n_PRB = n_subCHRBstart + j * (L_subCH * n_subCHsize— 1), with y = 0,1.

nsubCHRBstart ^maY be predefined or signalled and may provide an indication of the lowest RB index of the sub-channel with the lowest index. n_subCHsize may be predefined or signalled and may indicate the number of PRBs of each sub-channel. L_subCH may represent the number of contiguously allocated sub channels of the corresponding resource. Using the adjacent PSCCH and PSSCH scheme, more robust coding may be used, for example, using a lower code rate.

[0113] In the adjacent or non-adjacent schemes, one or more of the implementations for determining x^th and/or y^th resource location may be predefined or signalled. The predefined or the signalled parameters may depend, for example, on one or more of the following: the transport block location (e.g., timeslot), the geographic location of the WTRU, Doppler, WTRU density, a transmission mode (e.g., similar to LTE-V Mode 3 or LTE-V Mode 4), or a latency requirement (e.g., selection window).

[0114] One or more implementations are provided for sub-channelization of PSCCH, e.g., with a plurality RBs. FIG. 5 illustrates a sub-channelization example for non-adjacent and adjacent PSCCH and, for example, with PSCCH occupying 3 RBs. The three RBs may be allocated for use by a single PSCCH. In case of the non-adjacent allocation, the PSCCH resource m may be a set of three resource blocks with the physical resource block number, n_PRB determine using the equation n_PRB = n_PSCCHstart + 3 * m + j * NsubCH_< with j = 0,1,2, where n_PSCCHstart may be predefined or signalled as the starting RB index of the PSCCH pool. N_subCH ^maY he predefined or signalled as the total number of sub-channels in the corresponding resource pool, as illustrated in FIG. 5 (left sub-figure).

[0115] Other resource allocation schemes may be implemented. In an example, the SCI payloads may be processed, and rate matched bits may be distributed to two or more separate sections of contiguous RBs, e.g., to achieve frequency diversity gain. The SCI payloads may be processed, and some of the rate matched bits may be mapped to one section of contiguous RBs, and the same rate matched bits may be mapped to another section of contiguous RBs.

[0116] For adjacent allocation, as illustrated in FIG. 5 (right sub-figure), a (PSCCH, PSSCH) resource may occupy X consecutive RBs, with the first occupied RB index being Y. The PSCCH may be allocated to: 1 ) the r-th, the (Ύ + l)-th and the (Ύ + *)-th RB, 2) r-th, the (Ύ + */2)-th and the (Ύ + )-th RB, or 3) the V-th, or the (Y + X— l)-th and the (Y + )-th RB. In this example, the PSCCH resource m may be a set of three resource blocks with the physical RB number n_PRB = n_subCHRBstart + 2 * ⁿsubCHsize ^~P j j 0,1, and Tl_PRB NsubCHRBstart ^~P ^subCH * ⁿsubCHsize 1 Where

nsubCHRBstart ^maY bs predefined or signalled as indicating the lowest RB index of the sub-channel. The lowest index, n_subCHsize may be predefined or signalled as indicating the number of PRBs of each sub channel. L_subCH may be the number of contiguously allocated sub-channels of the corresponding resource.

[0117] A two stage/multi-stage SCI may be provided as described herein. A two-part SCI e.g., for NR V2X, may be referred to as two stage SCI or 2-stage SCI. A two-part SCI or a two stage SCI may be enabled using the frequency domain; a resource selection; or a frequency domain multi-stage SCI. The two-part SCI or the 2-stage SCI may be used to reduce WTRU decoding complexity.

[0118] The SCI payloads may be processed in one or more of the following ways: the two SCI parts may be jointly processed and rate matched bits may be distributed within two or more separate allocations of contiguous RBs; the two SCI parts may be jointly processed and a copy of rate matched bits may be allocated to one allocation of contiguous RBs, and another copy of rate matched bits may be allocated to a separate allocation of contiguous RBs; or the payloads may be partitioned and channel coding applied separately to the partitions, and, the encoded partitions may be resource mapped to different sections of contiguous RBs.

[0119] The first part of an SCI payload may include one or more of the field(s) that may be used for resource reservations or resource allocation. The fields in the first part of the SCI may include, for example, a data quality of service (Qos) field, e.g., comprising priority information, a resource reservation field, etc. The information indicated by these fields may be used by other WTRUs, e.g., other Mode 4 WTRUs in their resource selection process.

[0120] The second part of an SCI payload may include one or more field(s) related to PSSCH decoding. The second part of the SCI may include, for example, an MCS field, a retransmission index field, a transmission format field, etc. This information, e.g., indicated by these field(s), may be used to decode the PSSCH.

[0121] One or more of the following fields may be included in the first part of the SCI or the second part of the SCI: frequency resource location of initial transmission and retransmission field, a time gap between the initial transmission and retransmission field, etc.

[0122] One of more fields may be related to the QoS design of the sidelink system. For example, these fields may include PPPR, latency, etc. These fields may be included in SCI part 1. These fields may be used by, for example, a Mode 4 WTRU in its resource selection. Other fields, e.g., additional fields, may be assigned to the first part of the SCI or the second part of the SCI, for example, depending on their usage. The coding gain may be considered in partitioning the SCI payloads to two different parts.

[0123] A two-stage SCI enabled using a frequency domain may be provided as described herein. A two-part SCI may be implemented in the frequency domain by utilizing different sections of frequency domain resources. The different section of frequency domain resources may be utilized to achieve frequency diversity, for example, for reliable transmission of SCI and/or efficient resource selection for Mode 4 or the like WTRUs. The two-part SCI may be utilized to improve latency, e.g., by allowing parallel processing of the two SCI parts. Two separate and parallel processing of the fields may be applied for two different RBs.

[0124] FIG. 6 illustrates separating of the SCI contents (e.g., new radio SCI (NR SCI) contents) into two parts. The SCI contents may be separated into two parts, for example, based on the type of information.

For example, the first part of the SCI may include one of more of the following: a data QoS field, a resource reservation field, a frequency resource location field, a time gap between two transmissions field, etc. The second part of the SCI, for example, may include one or more of the following MCS, Retransmission index, Transmission format, etc. The separated SCI parts may be processed independently, e.g., as illustrated in FIG. 6. The two parts of SCI payloads may be processed, and resource mapped to different sections of RBs in the same sub-frame (or sub-slot). Such processing and resource mapping of the two parts of SCI payloads may be referred to as frequency domain two-stage SCI. As illustrated in FIG. 6, each of the SCI parts may independently perform one or more of the following: reordering and padding, CRC attachment, channel coding, rate matching, scrambling, modulation, or resource mapping.

[0125] The WTRUs interested in the contents of PSSCH may decode (e.g., first decode) the first-stage SCI. A WTRU interested in contents of PSSCH may be referred to as a WTRU intended to receive contents of PSSCFI. For example, a WTRU interested in the contents of the PSSCH may be the WTRU that is assigned to receive contents of the PSSCFI. Based on decoding the first-stage SCI, the WTRUs may know (e.g., may then know) the resources used for the PSSCFI. The interested WTRUs or the intended WTRUs may further decode the second-stage SCI. The interested WTRUs may decode the second-stage SCI so that decoding of the PSSCFI is possible. The interested WTRUs or the intended WTRUs may use the decoded second-stage SCI for decoding of the PSSCFI.

[0126] The WTRUs not interested in the contents of the PSSCFI or the WTRUs not intended to receive the contents of the PSSCFI may decode the first-stage SCI and not the second stage. Based on the decoded first-stage SCI, the WTRUs may know the resources used by the transmitting WTRU. This information may be used by the WTRU (e.g., an LTE-V Mode 4 WTRU) in its resource selection. For example, for the PSCCFI resource allocation for non-adjacent PSCCFI and PSSCFI structure (e.g., as illustrated in left sub-figures of FIG. 4 and FIG. 5). The WTRUs not interested in the reception of the data may check (e.g., only check) the first portion of the resources for PSCCFI, for example, since this portion of the PSCCFI may include the resource reservation information. For the PSCCFI resource allocation for adjacent PSCCFI and PSSCFI structure (e.g., right sub-figures of FIG. 4 and FIG. 5), the WTRUs not interested in the reception of the data may check the first one or two RBs in each sub-channel, e.g., to acquire the resource reservation information. This may reduce the WTRU's decoding complexity, for example, as less information may be decoded, and smaller mother code length of polar code may be applied. This may further provide potential benefits for other WTRUs sensing and resource selection with low latency.

[0127] FIG. 7 illustrates an example of a WTRU receiving PSCCFI and/or PSSCFI information. As illustrated in FIG. 7, at 702, the WTRU may receive the SCI part 1. SCI part 1 may include PSSCFI resource information. SCI part 1 may be referred to as the first part of the SCI, and SCI part 2 may be referred to as the second part of the SCI. At 702, the WTRU may decode the SCI part 1 for the resource reservation information from one or more WTRUs. At 704, the WTRU may determine whether it is interested in the PSSCH or the contents of the PSSCH. For example, the WTRU may determine whether it is intended to receive the associated PSSCH. If the WTRU determines that the WTRU is not interested in the contents of the PSSCH or it is not intended to receive the associated PSSCH, at 706, it may store the resource reservation information and data QoS information e.g., prose per-packet priority (PPPP) for its resource selection purpose. The WTRU may use the stored information for resource selection in case it is a Mode 4 WTRU. At 712, the WTRU may measure the physical sidelink shared channel reference signal received power (PSSCH-RSRP) and sidelink receive strength signal indicator (S-RSSI) information. At 714, the WTRU may store the measured PSSCH-RSRP and the measured S-RSSI information. For example, the WTRU may measure and/or store the information for future resource selection purpose.

[0128] At 704, if the WTRU determines that the WTRU is interested in the contents of the PSSCH or it is intended to receive the associated PSSCH, at 708, the WTRU may receive PSCCH comprising SCI part 2. At 710, the WTRU may decode (e.g., further decode) the SCI part 2 for the PSSCH decoding related information. Once the SCI part 2 is decoded, the WTRU may find the decoding related information for PSSCH and decode PSSCH accordingly.

[0129] A receiving WTRU (e.g., a WTRU interested or not inserted in the PSSCH) may be configured to transmit on a sidelink using the same resource pool as the transmitting WTRU. The WTRU may perform resource selection for the transmission on the sidelink based on the information received and decoded via SCI part 1. The SCI part 1 information may include, for example, PPPP, resource reservation, etc. The WTRU may perform resource selection by excluding certain resources that may be reserved/used by the transmitting WTRU.

[0130] The decoding of the SCI part 2 may depend on the PSSCH traffic type (e.g., groupcast/unicast or broadcast). If the PSSCH is for broadcast traffic type, no RNTI or group ID (e.g., group RNTI) may be applied to decoding of SCI part 2. If the PSSCH is for groupcast or unicast traffic type, RNTI or group ID may be applied to decoding of SCI part 2. Once the SCI part 2 is successfully decoded, the WTRU may find the resources for the PSSCH and decode the PSSCH accordingly.

[0131] FIG. 8 illustrates an exemplary WTRU (e.g., a Mode 4 WTRU) receiving PSCCH for its resource selection and sending PSSCH. As illustrated in FIG. 8, at 802, a WTRU may receive PSCCH including SCI part 1. The WTRU may scan the resource region for PSCCH comprising resource reservation related information (e.g., SCI part 1). At 804, the WTRU may measure PSSCH-RSRP and/or sidelink RSSI (S- RSSI). At 806, the WTRU may store data QoS information (e.g., PPPP) and the resource reservation information included in the SCI part 1. At 806, the WTRU may store the measured PSSCH-RSRP and S- RSSI, for example, for future resource selection. In case the WTRU has PSSCH data to send, at 808, the WTRU may perform a resource selection based on one or more of the stored PPPP, resource reservation, PSSCH-RSRP, or S-RSSI. At 810, the WTRU may send its PSSCH data on the selected resource.

[0132] Resource selection (e.g., efficient resource selection) may be provided as described herein. A Mode 4 WTRU may perform an efficient resource selection, for example, without relying on PSSCH-RSRP and S-RSSI measurement information. Instead, for example, the Mode 4 WTRU may rely on the resource reservation fields of the decoded SCI.

[0133] In an example, the resources reserved by other WTRUs (e.g., as indicated in the decoded SCI part 1) may be excluded from the set of available resources, and the sub-slots that are certain integer multiples of possible resource reservation interval from the sub-slot when the Mode 4 WTRU was transmitting may also be excluded from the set of available resources. The remaining resources may be considered as available resources.

[0134] In an example, the resources reserved by other WTRUs (e.g., as indicated in the decoded SCI part 1 ) may be excluded from the set of available resources, if the PPPP level of this data is lower than a threshold ( Thre ), and the sub-slots that are certain integer multiples of possible resource reservation interval from the sub-slot when the Mode 4 WTRU was transmitting may be excluded from the set of available resources. The remaining resources are considered as available resources. There may be no rank among these resources. The value of the threshold Thre may be configured, or may be compared with the transmitting WTRU's own data PPPP value. A similar mechanism may be applied to other QoS- related parameters, e.g., PPPR or latency.

[0135] If a Mode 4 WTRU collects a list of available resources at the PHY layer, its higher layer may apply the random selection on this list of resources. FIG. 9A illustrates an exemplary WTRU receiving 2- stage PSCCH and/or PSSCH for an intended WTRU and efficient resource selection based on the first stage PSCCH. As illustrated in FIG. 9A, at 902, a WTRU (e.g., a Mode 4 WTRU) may receive and decode PSCCH including SCI part 1. At 904, the WTRU may store resource reservation information and data QoS information or parameters related to QoS of the sidelink data (e.g., Priority information or PPPP) indicated in SCI part 1. At 906, the WTRU may determine whether it is interested in the PSSCH data or it is intended to receive the PSSCH data. If yes, the WTRU at 916 may receive PSCCH SCI part 2 and the

corresponding PSSCH. At 918, the WTRU may decode the PSSCH, e.g., based on PSSCH SCI part 2. Otherwise, at 908, the Mode 4 WTRU may determine whether it performs the efficient resource selection. If yes, at 914, the WTRU may (e.g., directly) do it based on the decoded SCI part 1 information. If the Mode 4 WTRU applies normal resource selection, at 910, the Mode 4 WTRU may measure the PSSCH-RSRP and S-RSSI for resource selection. At 912, the Mode 4 WTRU may perform normal resource selection. [0136] FIG. 9B illustrates an example of a WTRU receiving PSCCH and resource selection based on the first part of the SCI, as described herein. At 920, a WTRU may receive and decode PSCCH. The PSCCH may include SCI part 1. At 922, the WTRU may store data QoS information, (e .g., including PPPP information, latency, etc.), resource reservation information, PSSCH-RSRP and S-RSSI, etc., as described herein. At 924, the WTRU may determine whether it is intended to receive the associated PSSCH. If the WTRU is intended to receive the associated PSSCH, at 926, the WTRU may receive SCI part 2. The SCI part 2 may include PSSCH decoding information. At 928, the WTRU, using the decoded PSSCH information, may decode PSSCH.

[0137] If the WTRU determines that it is not intended to receive the associated PSSCH, at 930 the WTRU may determine whether it has sidelink (SL) data to send. If the WTRU determines that it has data to send, at 932 the WTRU may perform resource selection for the SL data transmission. For example, the WTRU may perform resource selection for the SL data transmission based on SCI part 1 information. At 934, the WTRU may send PSSCH data.

[0138] Frequency domain multi-stage SCI may be provided as described herein. The frequency-domain two-stage SCI may be extended to frequency-domain multi-stage SCI (e.g., three-stage SCI). Solutions provided herein may be applicable to the case of three sections of resources.

[0139] FIG. 10 illustrates an example of separating the NR SCI contents into three parts. The SCI contents may be separated, for example, based on the type of information. FIG. 10 further illustrates processing (e.g., independently processing) each part of the SCI payload. As illustrated in FIG. 10, the SCI part 1 may include one or more of the following fields: data QoS information ( e.g., including priority information or PPPP information), resource reservation, etc. One or more of the following fields may be in the SCI part 2: MCS, Retransmission index, transmission format, etc. One or more of the following fields may be in the SCI part 1 or SCI part 2: frequency resource location of initial transmission and

retransmission, time gap between the initial transmission and retransmission, etc. Other fields, for example, associated with the NR SCI to support unicast, groupcast, and/or broadcast SL transmission may be in the SCI part 3: new data indicator (NDI), HARQ process number, Redundancy version, code block group transmission information (CBGTI), etc. The resources utilized for the first two parts of the SCI information may be contiguous (e.g., for backward compatibility). The resource utilized for the last part of the SCI information may be separate from the former resources.

[0140] The SCI may be piggybacked on the PSSCH. As described herein, PSCCH may have dedicated resources for transmissions, for example two or more RBs. At least some SCI contents may be carried over an PSSCH resource. [0141] NR SCI (e.g., NR SCI format) may have large payloads, where for example some of the payloads follow the LTE SCI (e.g. SCI format 1), while for example some of the payloads may be different than the LTE SCI. In examples, we may leave the LTE SCI (e.g. SCI format 1) unchanged, but may assign some resources in the PSSCH for the added payloads for NR V2X. The SCI format may be separated into two parts. The first part may comprise the LTE SCI information, while the second part may comprise the NR SCI information. The two SCI fields may be separately processed. For example, the SCI fields may include one or more of: padding bits, CRC attachment, channel coding, rate matching, interleaving, or modulation. An indicator may be added to the LTE SCI payload (e.g., SCI part 1). This indicator may imply whether the NR SCI payload (i.e., SCI part 2) exists or not.

[0142] FIG. 11 illustrates an example where the NR SCI payload may be partitioned into two parts. The first part may be processed and allocated to the PSCCH resource and the second part may be parallelly processed and allocated to the PSSCH resource. The first part may comprise the payloads used by LTE V2X. Resource allocation related information comprising a first set of parameters (e.g., priority information, resource, reservation, frequency resource location of initial transmission and retransmission, etc.) may be separately processed and allocated to the PSCCH resource, while other PSSCH related information comprising a second set of parameters (e.g., MCS, retransmission index, transmission format, etc.) may be separately processed and allocated to the PSSCH resource.

[0143] A two-stage SCI may support groupcast or unicast transmission/reception. The separation of the SCI into two parts may be used for the groupcast or unicast sidelink transmission. The SCI part 1 may be related to resource reservation and may be broadcasted to (or be known by) each of the WTRUs (e.g., all WTRUs). The SCI part 2 may be related to unicast or groupcast sidelink data transmission/reception. It may be known to (e.g., only be known to) one or more WTRUs (e.g., a certain set or group of WTRUs). By separately processing SCI part 1 and SCI part 2, the SCI part 2 may be decodable (e.g., only decodable) by the destination WTRU or the WTRUs in the target group. This may result in an increase in the security level of the data.

[0144] FIG. 12 illustrates an example WTRU separately processing two parts of SCI for groupcast or unicast sidelink data transmissions. A WTRU receiving a sidelink transmission may separate the SCI payloads into two parts. As illustrated in FIG. 12, SCI part 1 may include the resource allocation related information. SCI part 2 may comprise the PSSCH decoding related information. The two SCI parts may be independently processed. The processing may include various operations, for example, payload reordering and padding, CRC attachment, channel coding, rate matching, scrambling, modulation and/or resource mapping. [0145] For SCI part 1 , the CRC may not be masked, e.g., as it may be expected to broadcast to WTRUs (e.g., all WTRUs) or to be received by the WTRUs. For SCI part 2, the CRC may be masked by a group-ID (e.g., a group radio network temporary identifier (group-RNTI)) or a WTRU-ID (e.g., an RNTI), for example, if the PSSCH is for the groupcast or unicast. Group-ID or group-RNTI may be introduced to indicate a group of WTRUs for groupcast. A WTRU-ID may be an RNTI, such as a configured scheduling RNTI (CS- RNTI) or an introduced RNTI for unicast sidelink data transmissions. This may prevent the WTRUs not in the group or not the target destination from decoding it. The rate matched bits may be scrambled by a scrambling sequence (e.g., gold sequence), for example after the channel coding and rate matching. The initial value of the scrambling sequence may be a constant (e.g., 510) for SCI part 1 , e.g., as it is the broadcast signal. The initial value of the scrambling sequence may be a function of group ID or RNTI, e.g., if the PSSCH is for the groupcast or unicast. After the scrambling operations, the bits may be modulated. A different modulation order may be applied to SCI part 1 and SCI part 2. The modulation symbols for SCI part 1 and SCI part 2 may be mapped to different resources.

[0146] FIG. 13 illustrates an exemplary WTRU receiving PSCCFI and PSSCH for broadcast, groupcast, or unicast sidelink data transmissions. At 1302, the WTRU may receive and decode the SCI part 1 for the resource reservation information, e.g., from some certain WTRUs. At 1304, the WTRU may determine whether it is interested in associated PSSCH or it is intended to receive associated PSSCFI. If the WTRU is not interested in the PSSCFI information, at 1306, the WTRU may store the resource reservation information and QoS of sidelink data (e.g., priority information or PPPP) for its future resource selection purpose, for example, if the WTRU is a Mode 4 WTRU. If the WTRU is interested in the PSSCFI information, the WTRU may decode the SCI part 2 for the PSSCFI decoding related information. The decoding of the SCI part 2 may depend on whether PSSCFI is for groupcast/unicast or broadcast. For example, the decoding of SCI part 2 may depend on whether PSSCFI is configured for a groupcast transmission or a broadcast transmission. At 1308, the WTRU may determine whether PSSCFI is for a groupcast/unicast transmission. If the PSSCFI is for groupcast/unicast transmission, the WTRU at 1314 may receive and decode PSCCFI including SCI part 2. The WTRU may use the group ID or group RNTI to decode PSCCFI part 2. At 1316, the WTRU may find the resources for PSSCFI and decode PSSCFI accordingly. If the PSSCFI is for a broadcast transmission, at 1310, the WTRU may simply receive PSCCFI without applying a group RNTI or group ID in the decoding of PSCCFI part 2. When SCI part 2 is decoded, at 1312, the WTRU may find the resources for PSSCFI and decode PSSCFI accordingly.

[0147] Two-stage support for carrier aggregation may be provided. NR V2X sidelink transmissions may support up to 8 carriers. Cross-carrier scheduling may be supported using two-stage SCI. The resource allocation scheduling may be in the primary carrier (e.g., only in the primary carrier). Since this information is in SCI part 1 , the primary carrier (or primary cell) may have PSCCH resources that carry SCI part 1 information. The SCI part 2 information may be in the PSCCH resources in secondary carrier (or secondary cell). For a Mode 4 WTRU not interested in receiving the PSSCH information, it may decode SCI part 1 information from the primary cell, e.g., and not other information. For the secondary cell, the Mode 4 WTRU may measure (e.g., only measure) the RSRP-PSSCH and S-RSSI for its resource selection. A mode 4 WTRU may not measure the RSRP-PSSCH and sense S-RSSI and may apply an efficient resource selection. Whether a Mode 4 WTRU uses the efficient resource selection or not may be determined based on one or more of the following factors: the WTRU capability (e.g., for low power or low-end WTRU, efficient resource selection procedure may be selected), configuration and/or indication from higher layer such as RRC and/or MAC, pre-defined or specified for NR mode 4 WTRU, or QoS or latency or reliability requirement of data to be transmitted by the Mode 4 WTRU, etc.

[0148] FIG. 14 illustrates an example WTRU receiving 2-stage PSCCH and/or PSSCH for intended WTRU and efficient resource selection based on the first stage PSCCH for carrier aggregation. At 1402, a Mode 4 WTRU may receive and decode PSCCH on a primary cell. The PSCCH received on the primary cell may include SCI part 1. At 1404, a Mode 4 WTRU may store data QoS information (e.g., PPPP information) and/or resource reservation information, for example, as indicated in received and decoded SCI part 1. At 1406, the WTRU may determine whether it is interested in the associated PSSCH data or it is intended to receive associated PSSCH. If the WTRU is interested in the PSSCH data, at 1416, the WTRU may receive and decode PSCCH over a secondary cell. The PSCCH received over the secondary cell may include SCI part 2. At 1418, the WTRU may decode the PSSCH, for example, using the decoded PSCCH SCI part 2.

[0149] If the Mode 4 WTRU is not interested in the associated PSSCH, at 1408 the WTRU may determine whether or not to apply the efficient resource selection. If the Mode 4 WTRU determines that it applies efficient resource selection, at 1414, the WTRU may perform the efficient resource selection. For example, the Mode 4 WTRU may perform the efficient resource selection based on the decoded SCI part 1 information. If the Mode 4 WTRU determines that it applies normal resource selection instead of the efficient resource selection, at 1410, the WTRU may measure the PSSCH-RSRP and S-RSSI on the secondary cell. At 1412 may apply normal resource selection, e.g., based on the PSSCH-RSRP and S- RSSI measurements.

[0150] Two-part SCI may be implemented in the time domain, for example, by allocating two or more parts of SCIs to different slots or sub-slots (e.g., one or more symbols) of time resources. The proposed schemes based on two-part SCI above may be accordingly implemented in the time domain. [0151] Two-stage SCI implementation(s) may be provided. In examples, as discussed herein, SCI part 2 may be transmitted on the PSSCH. SCI part 1 may include one or more of the following: other WTRU's sensing and resource selection; an indication of SCI part 2 resource; decoding of PSSCH of broadcast sidelink, etc. SCI part 1 contents for a unicast/groupcast sidelink may be different from SCI part 1 contents for a broadcast sidelink. SCI part 1 may have two formats, for example, SCI part 1 format 1 may be for unicast/groupcast sidelink traffic, and SCI part 1 format 2 may be for broadcast sidelink traffic.

[0152] Hybrid automatic request (HARQ) may be enabled for unicast/groupcast sidelink traffic. SCI part 1 format 1 may have one or more of the following fields: format indicator; data QoS or data QoS information; resource reservation interval; modulation of PSSCH/SCI part 2; part or all of destination (group) ID; PSSCH resource information of the current transmission; SCI part 2 format information; SCI part 2 resource information; PSSCH DMRS pattern; or PSFCH resource information.

[0153] A format indicator field may indicate whether the SCI part 1 is format 1 or format 2. SCI part 1 format 1 may be for unicast/groupcast sidelink traffic (with HARQ enabled). This information may be used for SCI part 2 decoding, e.g., since the SCI part 1 format 1 may indicate the existence of SCI part 2.

[0154] The data QoS field may include PSSCH data QoS information. It may include one or more of: priority information, latency, reliability, or communication range information. This information may be used for other WTRU's sensing and resource selection.

[0155] The resource reservation interval field may indicate the resource reservation period. This information may be used for other WTRU's sensing and resource selection and/or target UE's PSSCH decoding.

[0156] The modulation of PSSCH/SCI part 2 field may indicate the modulation order of PSSCH, e.g., if SCI part 2 is piggybacked on PSSCH. The modulation of SCI part 2 may be assumed to be similar or same as that of the PSSCH. The information in the modulation of PSSCH/SCI part 2 field may be used for SCI part 2 decoding and/or for PSSCH decoding. The coding rate of PSSCH may not be included in SCI part 1 format 1 , e.g., in order to reduce the SCI part 1 information size. This may serve to align the payload size of SCI part 1 format 1 and the payload size of SCI part 1 format 2 with minimum zero padding. This may reduce the blind decoding complexity of SCI part 1.

[0157] A part or all of destination (group) ID field may be used to indicate whether PSSCH is for a particular WTRU (group), for example, so that an untargeted WTRU may stop decoding SCI part 2 and/or PSSCH. The SCI part 1 format 1 may include part of the layer 1 destination (group) ID. The remaining layer

1 destination (group) ID information may be signaled in the SCI part 2 or may be used to mask the SCI part

2 CRC. SCI part 1 format 1 including part of layer 1 destination (group) ID may reduce the information size of SCI part 1 format 1 , for example, so that the information size of SCI part 1 format 1 is similar or almost similar to the information size of SCI part 1 format 2. This may reduce the zero-padding overhead to achieve similar or same SCI part 1 format 1 payload size and SCI part 1 format 2 payload size. Having similar payload size of SCI part 1 format 1 and SCI part 1 format 2 may reduce the blind decoding complexity.

[0158] Layer 1 destination (group) ID may be separated into two parts (e.g., SCI part 1 and SCI part 2). Various mechanisms may be provided for separating the Layer 1 destination ID into two parts. For example, if the layer 1 destination (group) ID is of length A bits. For B < A, one or more of the schemes described may be utilized.

[0159] In a scheme, SCI part 1 format 1 may include the B MSB (Most Significant Bits) of layer 1 destination (group) ID, while the A— B LSB (Least Significant Bits) of layer 1 destination (group) ID may be carried in SCI part 2 or used to mask the CRC of SCI part 2. In an scheme, SCI part 1 format 1 may include the B LSB of layer 1 destination (group) ID, while the A— B MSB of layer 1 destination (group) ID may be carried in SCI part 2 or used to mask the CRC of SCI part 2. In a scheme, SCI part 1 format 1 may include the B odd or even bits of layer 1 destination (group) ID, while the remaining bits of layer 1 destination (group) ID may be carried in SCI part 2 or used to mask the CRC of SCI part 2. In a scheme, SCI part 1 format 1 may include B bits generated from a function (e.g., hash function) of layer 1 destination (group) ID, while the remaining information of layer 1 destination (group) ID may be carried in SCI part 2 or used to mask the CRC of SCI part 2.

[0160] SCI part 1 format 1 may include partial destination (group) ID information. The partial destination (group) ID may prevent one or more untargeted WTRUs from decoding SCI part 2 and/or PSSCH. The untargeted WTRUs may be prevented from decoding SCI part 2 and/or PSSCH, for example, as these WTRUs may not have matched partial destination (group) ID.

[0161] Exclusion of the full destination (group) ID in the SCI part 1 format 1 may cause some untargeted WTRUs to decode SCI part 2. This may be because these untargeted WTRUs may have the same partial destination (group) ID. Since the remaining destination (group) ID information is delivered in SCI part 2, the untargeted WTRU may stop decoding PSSCH, e.g., after the WTRU decodes SCI part 2 and determines the full destination (group) ID is not a match. The number B of bits for destination (group) ID included in SCI part 1 format 1 may be selected to balance between the number of untargeted WTRUs to decoding SCI part 2 and the SCI part 1 payload size alignments among different formats.

[0162] The PSSCH resource information of the current transmission field may indicate the frequency domain region of the PSSCH. The blind retransmission may not be used for sidelink unicast/groupcast with HARQ enabled. SCI part 1 may indicate the PSSCH resource for the current transmission, for example, instead of the PSSCH resources that may be used for the current transmission and other retransmission(s) in blind retransmission. The number of bits for this field may be equal to [log₂ NUbchannei] · For example, for N subchannel = 20, this field may be 5 bits long. The PSSCH resource information of the current transmission field may have a smaller number of bits, for example, comparing to the case of supporting the indication of PSSCH frequency resource of the current transmission and the blind retransmission. Blind retransmission for sidelink unicast/groupcast with HARQ enabled may be supported. Multiple transmissions may occur before a HARQ feedback (or NACK) is received. The information in the PSSCH resource information of the current transmission field may be used for other WTRU's sensing and resource selection and/or for the target WTRU's PSSCH decoding.

[0163] The SCI part 2 format information field may indicate to a WTRU the SCI part 2 formats, for example, in case multiple SCI part 2 formats are supported. This information may be used to reduce the blind decoding number of target WTRU's SCI part 2 decoding.

[0164] The SCI part 2 resource information field may indicate the resource (e.g., PSSCH resource) information for SCI part 2. For example, aggregation levels 1 , 2, 4, 8 may be supported for SCI part 2. Aggregation level 1 may imply using 54 resource elements (e.g., without DMRS) for SCI part 2, aggregation level 2 may imply using108 resource elements (e.g., without DMRS) for SCI part 2, etc. This information may be used to reduce the blind decoding number of target WTRU's SCI part 2 decoding.

[0165] SCI part 2 resource information may depend on the SCI part 2 format information and/or modulation order of PSSCH and/or PSCCH resource size. The SCI part 2 resource information may be derived from one or more of the following: the SCI part 2 format information, the PSSCH modulation order, or the PSCCH resource size, and hence in such a case may not be signaled in SCI part 1. The SCI part 2 resource size may be derived such that the modulation and coding rate (or spectrum efficiency) of SCI part 2 is comparable or aligned with the modulation and coding rate (or spectrum efficiency) of SCI part 1.

[0166] The PSSCH DMRS pattern field may indicate the DMRS pattern for PSSCH. This information may be used for other WTRU's sensing and resource selection and/or for the target WTRU's PSSCH decoding. The physical sidelink feedback channel (PSFCH) resource information field may have a configured relation with the PSSCH transmission. The frequency domain of PSFCH may be indicated by SCI part 1. Table 1 illustrates an example functionality of SCI part 1 format 1 fields that may be used for sensing and resource selection, or for SCI part 2 decoding.

Table 1

[0167] SCI part 1 format 2 may be used for broadcast sidelink traffic. In such a case, it may be assumed for broadcast sidelink traffic, the SCI part 2 does not exist. SCI part 1 format 2 fields may include one or more of the following: format indicator; Data QoS; resource reservation interval; frequency resource location of current transmission and (next blind) retransmission; time gap between current transmission and next (blind) retransmission; retransmission index; MCS; MCS table index; or PSSCH DMRS pattern.

[0168] One or more of the following may apply for the SCI part 1 format 2 fields. Format indicator may be the same as SCI part 1 format 1. Data QoS may be the same as SCI part 1 format 1. Resource reservation interval may be the same as SCI part 1 format 1.

[0169] Frequency resource location of current transmission and (next blind) retransmission field may indicate the frequency domain region of the PSSCH. The blind retransmission may be used for sidelink broadcast or unicast/groupcast with HARQ disabled. SCI part 1 may indicate the PSSCH resource for the current transmission and next blind retransmission. The number of bits for this field may be equal to

this field IS 8 bits.

[0170] Time gap between current transmission and next (blind) retransmission field may indicate the time gap between the initial transmission and the next blind retransmission. Retransmission index field may indicate whether the current transmission is an initial transmission or a retransmission. MCS field may indicate the full 5 bits MCS entry of the used MCS table for PSSCH. For MCS table index field may indicate the MCS table used for PSSCH. MCS table index field may be indicated (e.g., implicitly indicated) by SCI CRC mask or other schemes. PSSCH DMRS pattern field may be the same as SCI part 1 format 1.

[0171] Devices (e.g., WTRUs), as described herein, may align the information size of SCI part 1 format 1 and SCI part 1 format 2. There may be two or more SCI part 1 formats. The payload sizes of these formats may be made similar or the same, for example, by adding padding (e.g., zero padding) to the longest SCI part 1 format. This may reduce the blind decoding attempts number of SCI part 1.

[0172] To reduce the zero padding of an SCI part 1 format, the information size of SCI part 1 format 1 and SCI part 1 format 2 may be aligned. Table 2 illustrates an example of the information size comparison between SCI part 1 format 1 and SCI part 1 format 2. In an example, if the destination ID size in SCI part 1 may be restricted to 8 bits. The two formats of SCI part 1 (format 1 and format 2) may have identical or similar information size.

[0173] Destination ID may have more bits, e.g., 16 bits. The 16-bit destination ID may be separated into two parts. The first destination ID part (e.g., of 8 bits) may be carried in the SCI part 1 format 1 , and the second destination ID part (e.g., of 8 bits) may be carried in SCI part 2. Destination ID may be carried as payload of SCI part 2 or be used to mask the CRC of SCI part 2. In the latter case, the second destination ID part may be used to generate the scrambling sequence for the rate matched bits of SCI part 2.

Table 2

[0174] SCI part 2 may exist for unicast or groupcast. SCI part 2 may comprise one or more of the following fields: a source ID; part or all of destination ID; a HARQ process ID, NDI and redundancy version (RV); PSSCH coding rate under the given modulation order; modulation and coding scheme (MCS) table index; position information of the Tx WTRU; indicator of HARQ NACK-only or HARQ ACK/NACK feedback scheme; indication of channel state information reference signals (CSI-RS) resource; request of CSI report; indication of CSI report; MIMO related information; CBG related information.

[0175] One or more of the position information of the Tx WTRU field, indicator of HARQ NACK-only or HARQ ACK/NACK feedback scheme field may be utilized for groupcast transmissions. One or more of the following fields may be utilized for unicast transmissions: indication of CSI-RS resource field, request of CSI report field, indication of CSI report, Multiple input multiple output (MIMO) related information field,

CBG related information field, etc. MIMO related information field may include beam indication, precoder index, etc. CBG related information field may include CBGTI. [0176] Source ID field may utilize for HARQ operation. Part or all of destination ID field may be carried in SCI part 2 payload. The part of all of destination ID field may be utilized for HARQ operation. Part or all of destination ID field may include several MSBs (Most Significant Bits) or LSBs (Least Significant Bits) of physical layer destination ID. Part or all of destination ID field may be the remaining information not included in SCI part 1 format 1. For HARQ operation, HARQ process ID, NDI information, and RV information may be utilized.

[0177] PSSCH coding rate under the given modulation order field may include the PSSCH coding rate for a given modulation order. Within each of three MCS tables, e.g., defined in NR, each modulation order may include up to 15 coding rates. In an example, a 4 bits long indication of the MCS entry for a given modulation order may be used.

[0178] MCS table index field for PSSCH may be utilized to indicate the MCS table. The MCS table may be utilized for PSSCH decoding. Position information of the Tx WTRU (e.g., for groupcast) field may include the source positioning information. The source positioning information may include zone ID and/or GPS location. The source positioning information may be carried in SCI part 2. The source positioning information may be utilized for HARQ operations (e.g., enabling or disabling of HARQ operations).

[0179] An MCS determination may be made from SCI part 1 and SCI part 2 may include PSSCH MCS values for SCI part 1 and SCI part 2. A receiver WTRU may determine the PSSCH MCS values from SCI part 1 and SCI part 2. The WTRU may obtain the modulation order from SCI part 1 format 1 , and the MCS table index from SCI part 2. The receiver WTRU may find the corresponding PSSCH MCS value from the MCS entries with the indicated modulation order and MCS table. For example, the receiver WTRU may find the corresponding PSSCH MCS value using the index of the PSSCH coding rate.

[0180] A receiver WTRU may determine destination ID from SCI part 1 and SCI part 2. The receiver WTRU may obtain part of the destination ID from SCI part 1. If this part of the destination ID is aligned with the receiver WTRU's part of the destination ID, then the receiver WTRU may continue to decode SCI part 2. Otherwise, the receiver WTRU may stop decoding SCI part 2. If the receiver WTRU decodes SCI part 2, it may combine the destination ID information in SCI part 2 with the destination ID information in SCI part 1 to obtain the full destination ID. If the combined full destination ID matches the full destination ID of this receiver WTRU, the receiver WTRU may decode the PSSCH for sidelink data. Otherwise, the receiver WTRU may skip decoding of the PSSCH for sidelink data.

[0181] Multiple SCI part 2 formats may be provided that may be different. For example, two different SCI part 2 formats may be provided. One SCI part 2 format may be for unicast transmissions (e.g., SCI part 2 format 1), and the other SCI part 2 formats may be for groupcast transmissions (e.g., SCI part 2 format 2). The following fields in SCI part 2 format 2 may be utilized for groupcast transmissions: position information of the Tx WTRU field, and indicator of HARQ NACK-only or HARQ ACK/NACK feedback scheme field. The following fields in SCI part 2 format 1 may be utilized for unicast transmissions: indication of CSI-RS resource field, Request of CSI report field, indication of CSI report, MIMO related information field, and CBG related information fields. A single format indicator to distinguish between SCI part 2 format 1 for unicast and SCI part 2 format 2 for groupcast may be utilized.

[0182] The information size of SCI part 2 format 1 and SCI part 2 format 2 may be aligned. In such a case, the field SCI part 2 format information in SCI part 1 format 1 may be ignored. The multiple SCI part 2 formats (e.g., depending on sidelink traffic type) may be differentiated based on destination (group) ID. For example, the destination ID for sidelink unicast may be within a certain range, while the destination group ID for sidelink groupcast may be within a different range. In an example, the MSB of destination ID for sidelink unicast may be of value“1 ," and the MSB of destination group ID for sidelink unicast may be of value "0.” The ID range information may be included (e.g., fully included) in SCI part 1 format 1 as partial destination (group) ID information. For example, after decoding SCI part 1 , a receiver WTRU may determine whether the sidelink transmission is for a unicast transmission or a groupcast transmission. The receiver may determine the SCI part 2 format. In this case, the SCI part 2 format information field may not be needed in SCI part 1 format 1.

[0183] Unicast/groupcast transmissions with FIARQ disabled may be provided. In an example, unicast/groupcast sidelink transmission with FIARQ disabled may be treated as a broadcast sidelink transmission. In another example, unicast/groupcast sidelink transmission with FIARQ disabled may be treated as unicast/groupcast sidelink with FIARQ enabled. In another example, unicast/groupcast sidelink transmission with FIARQ disabled may be treated as a separate case.

[0184] Unicast/groupcast sidelink transmission with FIARQ disabled may be treated as a broadcast sidelink transmission. SCI part 1 format 2 may be utilized in case of unicast/groupcast sidelink with FIARQ disabled. In this case, blind retransmission may be supported where the retransmission resources may be indicated using SCI part 1 format 2. In some exemplary transmissions as described herein, the SCI part 1 format 2 may not include destination ID. Such type of SCI may not favour the unicast/groupcast sidelink with FIARQ disabled. A device may include destination ID in SCI part 1 format 2. The destination ID in the SCI part 1 format 2 may allow an untargeted WTRU to stop decoding SCI part 2, for example, after successfully decoding SCI part 1. This may allow a unified design for unicast/groupcast sidelink transmission with FIARQ disabled and for broadcast sidelink transmission. For broadcast transmission, the destination ID may be a constant value (e.g., all zero ID or all one ID). A true destination ID may be used for unicast/groupcast transmission without HARQ. The resources for initial transmission and the retransmission may be linked in this case. The source ID may not be needed. The SCI part 2 may not exist for the case of unicast/groupcast transmission with HARQ disabled.

[0185] In case of unicast/groupcast sidelink transmission with HARQ disabled that may be treated as a broadcast transmission, the SCI part 1 format 2 may have increased information size (e.g., with part or all of destination ID). Table 3 illustrates an exemplary information size comparison between SCI part 1 format 1 and updated SCI part 1 format 2. FIG. 19 illustrates an example information size comparison between SCI part 1 format 1 and updated SCI part 1 format 2.

Table 3

[0186] FIG. 15 illustrates an exemplary receiver WTRU decoding SCI and PSSCH. As illustrated in FIG. 15, at 1502, a receiver WTRU may receive and decode SCI part 1. At 1504, the receiver WTRU may check whether the destination ID in SCI part 1 matches its ID. If the destination ID does not match the receiver WTRUs ID, the receiver WTRU may determine that the sidelink transmission is not for the receiver WTRU. The sidelink transmission may be a unicast or groupcast transmission with a different destination (group) IDs from the receiver WTRU. In such a case, at 1506, the receiver WTRU may store the information for its future resource selection and may not decode the corresponding SCI part 2 and/or PSSCH.

[0187] If the receiver WTRU determines that the sidelink transmission is for the receiver WTRU, for example, sidelink broadcast or sidelink unicast/groupcast with proper destination (group) IDs, at 1508, the WTRU may check the SCI part 1 format. [0188] For SCI part 1 format 2, the receiver WTRU may know there is no SCI part 2, and the receiver WTRU at 1510 may decode PSSCH, for example, using the information in SCI part 1. This may include the case of sidelink broadcast or sidelink unicast/groupcast with HARQ disabled.

[0189] For SCI part 1 format 1 , the receiver WTRU may determine that there is SCI part 2. At 1512, the receiver WTRU may receive SCI part 2 and decode SCI part 2. The receiver WTRU may decode SCI part 2 based on the information received in the SCI part 1 (e.g., SCI part 2 format, SCI part 2 resource size, PSSCH resource size, source or destination ID, data QoS information). The information received in the SCI part 1 may be explicit or implicit. This may be for the case of sidelink unicast/groupcast with FIARQ enabled. At 1514, the receiver WTRU may decode PSSCFI. For example, the receiver WTRU may decode PSSCH based on the information received in SCI part 2. At 1516, the WTRU may send FIARQ feedback, if applicable. For example, the applicable conditions may depend on a FIARQ scheme (e.g., FIARQ NACK- only), Tx-Rx distance, etc.

[0190] In case of unicast/groupcast sidelink transmission with FIARQ disabled that may be treated as a broadcast transmission, a receiver WTRU, for example based on SCI part 1 format, may know whether the FIARQ feedback is enabled or disabled. In case of SCI part 1 format 1 , the FIARQ feedback may be enabled, whereas in case of SCI part 1 format 2, the FIARQ feedback may be disabled. In the case of SCI part 1 format 1 , the receiver WTRU may distinguish between broadcast sidelink and unicast/groupcast sidelink with FIARQ disabled, for example, by checking the destination ID received in the SCI part 1.

[0191] Unicast/groupcast sidelink transmission with FIARQ disabled may be treated as

unicast/groupcast sidelink transmission with FIARQ enabled. In case of unicast/groupcast sidelink with FIARQ disabled, SCI part 1 format 1 may be utilized. The destination ID received in the SCI part 1 format 1 may prevent the untargeted WTRU from decoding SCI part 2. The SCI part 1 format 1 may include contents as described herein. In an example, the PSFCH resource information field in SCI part 1 format 1 may not be used.

[0192] A distinct SCI part 2 format may be utilized for the case of unicast/groupcast sidelink with FIARQ disabled. The distinct SCI part 2 format may be utilized to distinguish the case of unicast/groupcast sidelink with FIARQ disabled from the case of unicast/groupcast sidelink with FIARQ enabled. In this SCI part 2 format, a subset of fields as described herein may be utilized. For example, one or more of the Source ID field, Part or all of destination ID field, PSSCFI coding rate under the given modulation order field, or MCS table index field may be utilized for this SCI part 2 format.

[0193] FIG. 16 illustrates an exemplary receiver WTRU decoding SCI and PSSCFI. As illustrated in FIG. 16, at 1602, a receiver WTRU may receive and decode SCI part 1. At 1604, the receiver WTRU may check the SCI part 1 format. In case the SCI part 1 format is format 2, the receiver WTRU may determine the SCI part 1 information is for sidelink broadcast transmission and that a SCI part 2 may not be available. In this case, therefore, at 1610 the receiver WTRU may decode the PSSCH based on the SCI part 1 information.

[0194] In case the SCI part 1 format is Format 1 , at 1608, the receiver WTRU may check the destination ID of SCI part 1. If the destination ID is not the same as the receiver WTRU's ID, at 1610, the receiver WTRU may not decode SCI part 2 and/or the PSSCH.

[0195] If the destination ID is same as the receiver WTRU's ID, at 1612, the receiver WTRU may receive SCI part 2. At 1614, the receiver WTRU may decode SCI part 2 and the PSSCH, for example, based on the SCI part 2. At 1616, the receiver WTRU may check whether HARQ feedback is enabled. For example, if a new SCI part 2 format is used, the HARQ feedback may be disabled. In that case, at 1618, the receiver WTRU may not send the HARQ feedback. If a SCI part 2 corresponding to HARQ feedback is enabled, at 1620, the receiver WTRU may send HARQ feedback, for example, when applicable. For example, a receiver WTRU may determine whether HARQ feedback is enabled or disabled based on the indication in SCI part 1.

[0196] Unicast/groupcast sidelink with HARQ disabled may be treated as a separate case. For unicast/groupcast sidelink with HARQ disabled, SCI part 1 format 3 may be used. A difference between SCI part 1 format 3 and SCI part 1 format 2 may be that SCI part 1 format 3 includes additional destination

ID. Table 4 illustrates an example information size comparison between SCI part 1 formats 1 , 2 and 3.

Table 4 [0197] FIG. 17 illustrates an exemplary receiver WTRU decoding SCI and PSSCH. At 1702, a receiver WTRU may receive and decoded SCI part 1. At 1704, the receiver WTRU may check the SCI part 1 format. For SCI part 1 format 2, the receiver WTRU may know this is for sidelink broadcast and may know there is no SCI part 2. At 1712, the receiver WTRU may decode the PSSCH, for example, based on the SCI part 1 information.

[0198] For SCI part 1 format 3, the receiver WTRU may determine that this is for sidelink

unicast/groupcast transmission with FIARQ disabled. The receiver WTRU may determine that there is no SCI part 2. In this case, at 1706, the receiver WTRU may check whether the destination ID in SCI part 1 format 3 is same as the receiver WTRU's ID. If the destination ID is same as that of the receiver WTRU's ID, at 1710, the receiver WTRU may decode PSSCFI. Otherwise, at 1708, the receiver WTRU may not decode PSSCFI.

[0199] For SCI part 1 format 1 , at 1714 the receiver WTRU may check whether the destination ID of SCI part 1 format 1 is same as the WTRU's ID. If the destination ID is not same as the receiver WTRU's ID, the receiver, at 1716, may not decode SCI part 2 and/or PSSCFI. If the destination ID is same as the receiver WTRU's ID, at 1718, the receiver WTRU may receive and decode SCI part 2. At 1720, the receiver WTRU, using the SCI part 2 information, may further decode PSSCFI. At 1722, the receiver WTRU may send FIARQ feedback, for example, if applicable. A receiver WTRU may determine whether the FIARQ feedback is enabled or disabled, for example, based on the SCI part 1 format. In case of SCI part 1 format 1 , the receiver WTRU may determine that the FIARQ feedback is enabled. In case of SCI part 1 format 3, the receiver WTRU may determine that the FIARQ feedback is disabled.

[0200] RE mapping for SCI part 2 may be provided as described herein. The SCI part 1 may occupy the PSCCFI resources (e.g., all the resources of PSCCFI). SCI part 2 may be piggybacked on PSSCFI.

[0201] In mechanism 3 of PSCCH/PSSCH multiplexing, the resource element (RE) mapping for SCI part 2 may follow frequency-first and time-second rule. In such a mapping, SCI part 2 REs may be mapped across a frequency-time grid in frequency-first fashion.

[0202] In the case of mechanism 3 PSCCH/PSSCH multiplexing, as described herein, a part of PSCCFI and the associated PSSCFI may be transmitted using overlapping time resources in non-overlapping frequency resources. Another part of the associated PSSCFI and/or another part of the PSCCFI may be transmitted using non-overlapping time resources.

[0203] A starting symbol for the PSSCFI carrying SCI part 2 may be pre-defined or may be pre configured. SCI part 2 may be available for unicast sidelink transmission or groupcast sidelink

transmission. In each of these cases, a session may be established. The starting symbol may be pre configured, for example, during the session establishment. [0204] FIG. 18 illustrates an exemplary resource element mapping for PSSCH carrying SCI part 2 in case of the PSCCH/PSSCH Mechanism 3 multiplexing. As illustrated in FIG. 18, the starting symbol for the PSSCH carrying SCI part 2 may be the first symbol after the symbol carrying automatic gain control (AGC). In this case, in frequency domain, the starting RE for SCI part 2 may be the first RE after PSCCFI. This design may reduce SCI decoding latency. The SCI part 2 symbols may be received early (e.g., at the earliest possible), which may assist the early decoding of SCI part 2 and/or PSSCFI.

[0205] FIG. 19 illustrates an exemplary resource element mapping for PSSCFI carrying SCI part 2 in case of PSCCH/PSSCH Mechanism 3 multiplexing. As illustrated in FIG. 19, the starting symbol for PSSCFI carrying SCI part 2 may be the first symbol after the last PSCCFI symbol. This symbol may be the front-end PSSCFI DMRS symbol. The resource element mapping of PSSCFI with SCI part 2 around the DMRS symbol may achieve a better decoding performance, e.g., due to the accurate channel estimation. As further illustrated in FIG. 19, if the SCI part 2 occupies more resource elements than the front-end DMRS symbol, then the remaining SCI part 2 may occupy the next OFDM symbol from the lowest resource block index. The reliability requirement of SCI part 2 may be higher than that of PSSCFI data. In this case, in frequency domain, the starting RE for SCI part 2 may be the first or last RE in the subchannel.

[0206] The selection of the two schemes as illustrated in FIG. 18 and FIG. 19 may be pre-defined or (pre)configured, for example, if both resource element mapping schemes are supported. The selection between these two schemes may depend on data QoS. For example, for low latency data, the first scheme may be used, e.g., because the SCI part 2 may be located in the front part of a slot. This may enable early decoding of the SCI part 2. For high reliable data, the second scheme may be used, e.g., because the SCI part 2 may be located at the resource with accurate channel estimation. This may enhance transmission reliability of the SCI part 2.

[0207] SCI part 2 resource mapping in mechanism 1 B or mechanism 2 of PSCCH/PSSCH multiplexing are described herein. In mechanism 1 B of PSCCH/PSSCH multiplexing, PSCCFI and the associated PSSCFI may be transmitted using non-overlapping time resources. The frequency resources used by the two channels may be different. In mechanism 2 of PSCCH/PSSCH multiplexing, PSCCFI and the associated PSSCFI may be transmitted using non-overlapping frequency resources in the time resources used for transmission. The time resources used by the two channels may be the same.

[0208] FIG. 20 illustrates an exemplary resource element mapping for PSSCFI carrying SCI part 2 in Mechanism 2 or Mechanism 1 B of PSCCH/PSSCH multiplexing. As illustrated in FIG. 20, for mechanism 1 B or mechanism 2 of PSCCH/PSSCH multiplexing, the starting symbol for the PSSCFI carrying SCI part 2 may be the first symbol after AGC. In this case, in the frequency domain, the starting RE for SCI part 2 may the first RE of the subchannel. This may reduce SCI decoding latency and may be accompanied with DMRS for good channel estimation. As further illustrated in FIG. 20, if the SCI part 2 occupies more resource elements than the front-end DMRS symbol, then the remaining SCI part 2 may occupy the next OFDM symbol from the lowest resource element index, enabling the SCI part 2 to be decoded early (e.g., at the earliest possible time).

[0209] In an example, as illustrated in FIG. 21 , the remaining SCI part 2 information may occupy the next DMRS symbol. This may enable that the SCI part 2 to be decoded with high reliability, for example, due to the accurate channel estimation.

[0210] The selection of these two schemes as illustrated in FIG. 20 and FIG. 21 may be pre-defined or (pre)configured, for example, if both resource element mapping schemes are supported. The selection between these two schemes may depend on data QoS. For example, for low latency data, the first scheme may be used, e.g., because the SCI part 2 may be located in the front part of the slot, which may enable its early decoding. For high reliable data, the second scheme may be used, e.g., because the SCI part 2 may be located at the resource with accurate channel estimation. This may enhance transmission reliability of SCI part 2.

[0211] Structures for PSCCFI and PSSCH multiplexing may be provided. Mechanisms for multiplexing PSCCH and PSSCH, in connection with FIG. 3, may include: Mechanism 1A, Mechanism 1 B, Mechanism 2, and Mechanism 3. In Mechanism 1A and Mechanism 1 B, PSCCFI and PSSCH may be TDM multiplexed. The decoding of PSSCH may be started after (e.g., immediately after) the PSCCFI decoding, for example, to achieve low latency. Mechanisms 1 A and 1 B provides a fixed link budget for control channel transmissions across WRTUs. In case of Mechanism 2, PSCCFI and PSSCH may be FDM multiplexed. In this case, a common sensing mechanism may be provided for control and data channel transmissions. Mechanism 2 may provide sufficient control channel capacity. In case of Mechanism 3, the PSCCFI and PSSCH may use hybrid TDM and FDM multiplexing. The PSCCFI and PSSCH channel resources may be flexibly configured within the common resource.

[0212] A structure for Mechanism 1 A PSCCFI and PSSCH multiplexing may be provided. In case of Mechanism 1A, in a TDM multiplexing scheme, AGC, control, control DMRS, data, data DMRS and GAP may share 14 ODFM symbols in a slot. In DFT-s-OFDM waveform, the AGC and GAP may use the first and the last OFDM symbol, for example, as in LTE V2X. The number of OFDM symbols for control and control DMRS may vary as described herein.

[0213] The control and control DMRS may occupy a fixed number of consecutive OFDM symbols after the AGC symbol. For example, the control and control DMRS may use the second to the fourth OFDM symbols, and the control DMRS may be placed on the third OFDM symbol. [0214] The number of OFDM symbols for control and control DMRS may be configurable, for example, semi-statically configurable. The number of OFDM symbols may depend on one or more parameters associated with resource pool configurations. For example, the number of OFDM symbols for control and control DMRS may depend on the configured sub-channel sizes, which may be in a given range (e.g., 1 to 4 OFDM symbols). The larger the sub-channel size, the smaller number of OFDM symbols that may be used for control information. The number of subcarriers per OFDM symbol may increase with the sub channel size. The control information may be transmitted or received using a lesser number of OFDM symbols. The linkage between the number of OFDM symbols for control information and the sub-channel sizes may be pre-defined or may be pre-configured in the resource pool configurations.

[0215] For small sub-channel sizes, for example, comprising 4 RBs, control information may be mapped to 96 REs, for example, if the control information occupies two OFDM symbols. The reliable transmissions of SCI may employ more resources for control information and one more OFDM symbols may be allocated to control information. For large sub-channel sizes such as, for example, 20 RBs, control information may be mapped based on 240 REs per OFDM symbol. Accordingly, a single OFDM symbol may be sufficient for the control information.

[0216] The number of OFDM symbols for control information may be dynamically adjusted. For example, the number of symbols assigned may depend on data QoS (e.g., priority, reliability, latency, communication range) or vehicle speed. For data with higher priority, higher reliability requirements or larger communication range, a larger number of OFDM symbols may be assigned for the control information. For a data with lower latency requirements, a smaller number of OFDM symbols may be assigned for the control information. For a vehicle operating at higher speed, more OFDM symbols may be assigned for the control information.

[0217] One or more associations between data QoS (or vehicle speed) and the number of OFDM symbols may be pre-specified and/or configured for control information, for example, via RRC messages (e.g., using IE SL-CommResourcePoolV2X). If the data priority level is below 4 (e.g., higher priority), the number of OFDM symbols for control information may be 3, for example. If the data priority level is above 4 (e.g., lower priority), the number of OFDM symbols for control information may be 2. If the data priority level is below 3, the number of OFDM symbols for control information may be 3. If the data priority level is below 6, the number of OFDM symbols for control information may be 2. Otherwise, the number of OFDM symbols for control information may be 1. The configuration index may be signalled via RRC messages. If more than one association is configured, one of them may be further selected or activated/deactivated dynamically by an L1 or a MAC CE. [0218] In a dynamically adjustable control information time duration scheme, a transmitter may dynamically adjust control information duration based on its data QoS. The receiver may perform blind decoding of control information by trying different numbers of OFDM symbols. FIG. 22 illustrates an example of WTRU SCI decoding, where a dynamic number of control OFDM symbols may be employed. As illustrated in FIG. 22, at 2202, a WTRU may configure relationship between the number of control OFDM symbols and data QoS information. The WTRU may receive or generate the configuration information regarding the relation between the number of control OFDM symbols and the data QoS information (e.g., priority information or priority value). At 2204, the WTRU may demodulate OFDM symbols with control information. At 2206, the WTRU may set the number of control OFDM symbols to a minimum possible vale. At 2208, the WTRU may perform channel decoding of the SCI. At 2210, the WTRU may check the CRC of the SCI. If the CRC check fails, at 2212, the WTRU may increase the number of control OFDM symbols. If the CRC check passes, at 2218, the WTRU may further check the contents of the SCI for the data QoS information. If the data QoS information matches the number of control OFDM symbols utilized in the current SCI decoding based on the configuration, at 2220, the SCI decoding may be determined to have been successful. Otherwise, the decoding may be determined to have been failed. At 2212, the WTRU may increase the number of control OFDM symbols. At 2214, the WTRU may determine whether the number of control OFDM symbols is greater than a maximum possible number of OFDM symbols. If the number of control OFDM symbols is greater than a maximum possible number of OFDM symbols, at 2216, the SCI decoding may be determined to have been failed. Otherwise, the WTRU may perform SCI decoding with the increased number of control OFDM symbols.

[0219] Frame structure of PSCCFI and/or PSSCH may be provided as described herein. For example, after AGC, GAP and the control (control DMRS) symbols in a slot are set, the data and data DMRS may occupy the remaining OFDM symbols. In an example, the data DMRS may be uniformly placed among the remaining OFDM symbols. The density of the data DMRS may depend on one of more factors, including for example, the vehicle speed. The DMRS pattern may reuse the designs in NR. FIG. 23 illustrates an exemplary frame structure of PSCCFI and PSSCH in DFT-s-OFDM waveform.

[0220] FIG. 24 illustrates an exemplary frame structure of PSCCFI and PSSCH in a CP-OFDM waveform. As illustrated in FIG. 24, in CP-OFDM waveform, the AGC and GAP may use the first and the last OFDM symbol, for example, like LTE V2X. The control and control DMRS may occupy one or more of the following: a fixed number of consecutive OFDM symbols after the AGC symbol; a configurable number of consecutive OFDM symbols, wherein the configuration may depend on other parameters in the resource pool; or a dynamically adjustable number of consecutive OFDM symbols which may be based on data QoS. As illustrated in FIG. 24, the control information and control DMRS may be multiplexed on the same OFDM symbol. As further illustrated in FIG. 24, the data and data DMRS may be placed on the remaining OFDM symbols, where data DMRS may be distributed over a few OFDM symbols.

[0221] SCI in PSCCFI and PSSCH multiplexing Mechanism 1 A may be include time resource location and/or frequency resource location as described herein. In slot-based scheduling, the SCI in Mechanism 1 A may not indicate the time resource location for PSSCH. In mini-slot-based scheduling, the SCI in Mechanism 1 A may include the time resource duration for PSSCH. The SCI in Mechanism 1A may include the frequency resource location for PSSCH, for example, only if there is retransmission (or repetition). In case of retransmission (or repetition), the SCI in Mechanism 1A may include the frequency resource location (i.e., the starting sub-channel index) for the next repeated PSSCH.

[0222] CORESET and search space design in PSCCH and PSSCH multiplexing Mechanism 1 B may be provided as described herein. In Mechanism 1 B, control and data may not share the same frequency resources. In this scheme, the association between PSCCH and PSSCH may be specified in the SCI. This may increase the SCI signalling as compared to Mechanism 1A.

[0223] Mechanism 1 B may provide flexibility with respect to the PSCCH frequency resource sizes. This may be beneficial for the reliable transmissions with variable communication ranges. For example, for a data service with a large communication range, the number of frequency resources may be larger.

[0224] A control resource set (CORESET) may be defined for the first several OFDM symbols. The frequency domain resource indication of the CORESET may be designed for PSCCH. The CORESET configuration parameters may be associated with the corresponding PSSCH resource pool configuration. The bitmap indication of frequency domain resources may vary and, for example, may not be fixed as 6 RBs per bit as in the CORESET definition for NR downlink (DL). It may be reused for NR V2X sidelink configuration (e.g., PSCCH configuration). Each bit may indicate that the number of RBs is equal to the sub-channel size configured in the resource pool. The number of RBs corresponding to each bit may depend on the resource pool frequency domain size, for example, both sub-channel size and number of sub-channels in a resource pool. The time duration of a CORESET may be related to system condition. For example, if there are a relatively large number of highly reliable data transmissions in SL, the time duration of a CORESET may be larger, e.g., 3 OFDM symbols. If there are a relatively large number of low latency data transmissions in SL, the duration of a CORESET may be smaller. A network entity may configure several CORESETs with different time durations. The associate WTRUs with low latency requirement for data transmission may utilize a CORESET with a smaller duration, and the associate WTRUs with relaxed latency requirements for data transmission may request a CORESET with a large duration.

[0225] To support different reliability transmissions of control information, one or more aggregation levels may be defined for a sidelink. The search space configuration parameters may be associated with the corresponding PSSCH resource pool (or the corresponding PSSCH resource pool region) configuration and/or the PSCCH resource pool (or PSCCH resource pool region) configuration. The CCE size for the sidelink may be different from NR downlink. The CCE size may be related to sub-channel size and/or the resource pool frequency domain size, for example, instead of defining each CCE to be a fixed size of 72 REs. The supported aggregation levels for sidelink may depend on data QoS requirements.

[0226] SCI contents in PSCCH and PSSCH multiplexing Mechanism 1 B may be provided as described herein. In an exemplary connection with slot-based scheduling, the SCI in Mechanism 1 B may not indicate the time resource location for PSSCH. In an exemplary connection mini-slot-based scheduling, the SCI in Mechanism 1 B may include the time resource duration for PSSCH.

[0227] The SCI in Mechanism 1 B may include the frequency resource location for PSSCH (e.g., the starting sub-channel index and the number of contiguously allocated sub-channels), for example, in case there is no retransmission (or repetition). The SCI in Mechanism 1 B may indicate frequency resource location (e.g., the starting sub-channel index and the number of contiguously allocated sub-channels) for the next repeated PSSCH, for example, if there is retransmission (or repetition).

[0228] Structure of the PSCCH and PSSCH multiplexing Mechanism 2 may be provided as described herein. The number of RBs for PSCCH may be fixed or pre-specified to a fixed number (e.g., 2 RBs for backwards compatibility), configurable in a semi-static way (e.g., by RRC signalling), or dynamically adjusted or selected. The selection may be related to data QoS. In a case of dynamic selection based on data QoS, the blind detection scheme as illustrated in FIG. 22 may be applied with the replacement of time domain (e.g., different number of OFDM symbols) to frequency domain (e.g., different number of RBs).

[0229] Search space design in PSCCH and PSSCH multiplexing Mechanism 3 may be provided as described herein. In case Mechanism 3 is employed, time or frequency resources for PSCCH may be flexibly shared with PSSCH, limitations for sidelink resource allocation may be less, and more space may be available for PSCCH/PSSCH channel schemes. Where Mechanism 3 is employed, blind detection of PSCCH may be used. To reduce the number of blind detections of PSCCH in Mechanism 3, some restrictions for the time/frequency resources for PSCCH may be (pre)configured in the resource pool configurations. In an example, the PSCCH may start from the first subcarrier of the first sub-channel. Several possible numbers of frequency resources (e.g., aggregation level) for PSCCH may be configured to restrict the number of blind detections. This may correspond to a set of aggregation levels.

[0230] The transmitting WTRU may select a configured number of subcarriers based on the data QoS requirements. For example, for data with higher reliability requirements or higher priority, the WTRU may select more frequency resources for PSCCH. The receiving WTRU may perform blind detection of the PSCCH. As part of the blind detection, the receiving WTRU may check if the occupied PSCCH resources match the contents (e.g., QoS) of the SCI.

[0231] Besides the frequency resources, the time resource for PSCCH may be configured (e.g., (pre)configured). In examples, the PSCCH may start from the first OFDM symbol in each resource. Several possible numbers of time resources (e.g., OFDM symbols) for PSCCH may be configured to restrict the number of blind detections. The transmitting WTRU may select a number of OFDM symbols from the configured list based on the data QoS requirements. For example, for data with lower latency requirements, it may select less time resources or symbols for PSCCH. At the receiver side, the WTRU SCI decoding in dynamic number of control OFDM symbols may operate based on as illustrated in FIG. 22. Two- dimensional blind detection with SCI-content based check may be applied, for example, if the time resources and the frequency resources are flexible. The DMRS for PSCCH and PSSCH in Mechanism 3 may be jointly designed.

[0232] SCI contents in PSCCH and PSSCH multiplexing Mechanism 3 may be provided as described herein. Mechanism 3 may include the time resource duration for PSSCH, for example, based on whether the scheduling is a slot-based scheduling or a mini-slot-based scheduling. For example, the SCI in Mechanism 3 may include or indicate the time resource duration for PSSCH, for example, when the scheduling is a mini-slot-based scheduling.

[0233] If there is no retransmission (or repetition), the SCI in Mechanism 3 may include the frequency resource location for PSSCH (e.g., the number of contiguously allocated sub-channels). If there is retransmission (or repetition), the SCI in Mechanism 3 may indicate frequency resource location (e.g., the starting sub-channel index and possibly, the number of contiguously allocated sub-channels) for the next repeated PSSCH.

[0234] The above mechanisms may coexist, each working under different conditions. For example, Mechanism 1 may be used for a resource pool to support a low latency traffic scenario. Mechanism 2 may be used for a resource pool to support a periodic traffic scenario. Mechanism 3 may be used for a resource pool to support a scenario where traffic may have to satisfy various requirements.

[0235] The processing may depend on numerologies and/or frequency range (FR). For example, each of the AGC and the GAP may take one OFDM symbol. However, the AGC settling time and TX/RX switching time may depend on the numerology of the resource pool, and the channel frequency. FIG. 25 depicts a table that lists example symbol durations for each sub-carrier spacing. As illustrated in FIG. 25, in LTE V2X, the 15 kHz SCS may be used and each OFDM symbol may be 71 me. The AGC settling time may depend on Frequency Range (FR). For example, the settling time may be 15 me in FR1 or 10 me in FR2. Similarly, the TX/RX switching time may depend on FR. For example, the TX/RX switching time may be 13 me in FR1 or 7 me in FR2.

[0236] In order to support different numerology and FR for V2X sidelink, different structures for V2X may be depend on the numerology and/or FR. For example, the number of AGC and TX/RX switching symbols may be decreased with the increase of carrier frequency (e.g., FR2 > FR1) for the same numerology. The number of control (and/or DMRS for control) symbols may remain the same while the number of data (and/or DMRS for data) symbols may be increased such that the total number of symbols in a slot may remain the same for different numerology. In a case, the number of data (and/or DMRS for data) symbols may remain the same while the number of control (and/or DMRS for control) symbols may be increased such that the total number of symbols in a slot remains the same for different numerology. In a case, both the number of control and data (and/or DMRS for control and data) symbols may be increased for the same numerology when the carrier frequency is increased (e.g., FR1 to FR2).

[0237] FIG. 26 illustrates an exemplary frame structure of PSCCFI and PSSCH for an example where the subcarrier spacing (SCS) is 120 kHz. For SCS of 120 kHz, each OFDM symbol duration may be 8.9 me. Accordingly, the AGC settling time in both FR1 and FR2 (i.e., 15 me and 10 me) may occupy two OFDM symbols. Also, the TX/RX switching time in FR1 (13 me) may last two OFDM symbols. The TX/RX switching time in FR2 (7 me) may last one OFDM symbol.

[0238] FIG. 27 illustrates an exemplary frame structure of PSCCFI and PSSCH wherein the SCS is 240 kHz. For SCS of 240 kHz, each OFDM symbol duration may be 4.4 me. The AGC settling time may occupy 4 and 3 OFDM symbols for FR1 and FR2, respectively. The TX/RX switching time may occupy 3 and 2 OFDM symbols for FR1 and FR2, respectively.

[0239] By way of an example, the number of AGC and TX/RX switching (e.g., GAP symbol illustrated in FIG. 26) symbols may be increased with the increase of numerology. The number of control (and/or DMRS for control) symbols may remain the same, while the number of data (and/or DMRS for data) symbols may be reduced such that the total number of symbols in a slot remains the same for different numerology. As illustrated in left (or right) figures of FIG. 26 and FIG. 27, for a given carrier frequency (e.g., FR1), the AGC and TX/RX switching symbols may be increased when the numerology increases (e.g., SCS may be increased from 120 kHz to 240 kHz). The two examples - where the number of AGC and TX/RX switching symbols may be decreased with the increase of carrier frequency for the same numerology, and where the number of AGC and TX/RX switching symbols may be increased with the increase of numerology - may be combined to determine the number of AGC and TX/RX switching symbols based on the numerology and carrier frequency, as illustrated in FIG. 26 and FIG. 27. [0240] The extension of AGC and GAP symbol with increased numerology (e.g., SCS 120kHz to 240kHz) and/or decreased carrier frequency (e.g., FR2 to FR1) extension using Mechanism 1A are illustrated in FIG. 25 and FIG. 26 by way of example. Similar extension may be applied to other PSCCH and PSSCH multiplexing schemes.

[0241] Worst case design principles may be applied to pre-specify the fixed structures for different numerology and/or FR. For example, the left structure in FIG. 27 may be used or specified for various SCS and carrier frequencies (including FR1 and FR2).

[0242] Processing may be configured (e.g., by RRC message) to use either a pre-specified fixed structure based on the worst-case design principle, or any of the potential flexible structures depending on the configured numerology and carrier frequency. If a pre-specified fixed structure is configured, the WTRU may directly conduct SL communication. If the flexible structure is configured, the WTRU may use the corresponding structure based on carrier frequency and SCS information, as described herein, before conducting SL communication, for example.

[0243] Although the features and elements may be described herein in particular combinations, each feature or element may be used alone, without the other features and elements, and/or in various combinations with or without other features and elements. Although the solutions described herein consider New Radio (NR), 5G or LTE, LTE-A specific protocols, the features described herein may not be restricted to such scenarios and may be applicable to other wireless systems such as based on 802.11 technologies, etc.

Claims

CLAIMS What is claimed is:

1. A wireless transmit/receive unit (WTRU) comprising:

a processor configured to:

receive via a physical sidelink control channel (PSCCH) a first part of sidelink control information (SCI), wherein the first part of the SCI comprises resource reservation information and data quality of service (QoS) information associated with a physical sidelink shared channel (PSSCH);

decode the first part of the SCI;

determine whether the WTRU is intended to receive the PSSCH;

on a condition that the WTRU is intended to receive the PSSCH and the PSSCH is configured for a unicast transmission or a groupcast transmission,

receive a second part of the SCI,

decode the second part of the SCI and determine decoding related information associated with the PSSCH, and

decode the PSSCH based on the decoding related information associated with the PSSCH obtained from decoding the second part of the SCI and the resource reservation information associated with the PSSCH obtained from the first part of the SCI; and on a condition that the WTRU is intended to receive the PSSCH and the PSSCH is configured for a broadcast transmission, decode the PSSCH based on the decoding related information associated with the PSSCH and the resource reservation information associated with the PSSCH obtained from the first part of the SCI.

2. The WTRU of claim 1 , wherein the processor is further configured to:

determine whether the WTRU has data to transmit on its PSSCH;

on a condition that the WTRU has the data to transmit on its PSSCH, perform resource selection based on the decoded first part of the SCI comprising the resource reservation information and the data QoS information.

3. The WTRU of claim 2, wherein the processor is configured to perform the resource selection by excluding resources indicated by the first part of the SCI.

4. The WTRU of claim 1 , wherein a determination of whether the WTRU is intended to receive the PSSCH is based on a parameter included in the decoded first part of the SCI.

5. The WTRU of claim 1 , wherein the processor is further configured to measure and store a physical sidelink shared channel-reference signal received power (PSSCH-RSRP) value and a sidelink receive strength signal indicator (S-RSSI) value for resource selection.

6. The WTRU of claim 1 , wherein the first part of the SCI is for a broadcast transmission, a unicast transmission, or a groupcast transmission.

7. The WTRU of claim 1 , wherein

on a condition the PSSCH is configured for a unicast transmission or a groupcast transmission, the second part of the SCI is masked with a partial destination (group) ID or a full destination (group) ID; and on a condition the PSSCH is configured for a broadcast transmission, the second part of the SCI is not masked, and the decoding related information associated with the PSSCH is obtained from the second part of the SCI without decoding the second part of the SCI.

8. The WTRU of claim 1 , wherein rate matched bits of the second part of the SCI are scrambled with a sequence based on a destination (group) ID.

9. The WTRU of claim 1 , wherein the second part of the SCI is piggybacked on a PSSCH transmission.

10. A sidelink control information (SCI) decoding method comprising:

receiving via a physical sidelink control channel (PSCCH) a first part of SCI, wherein the first part of the SCI comprises resource reservation information and data quality of service (QoS) information associated with a physical sidelink shared channel (PSSCH);

decoding the first part of the SCI;

determining whether a wireless transmit/receive unit (WTRU) is intended to receive the

PSSCH;

receiving a second part of the SCI,

decoding the second part of the SCI and determining decoding related information associated with the PSSCH, and decoding the PSSCH based on the decoding related information associated with the PSSCH obtained from decoding the second part of the SCI and the resource reservation information associated with the PSSCH obtained from the first part of the SCI; and

on a condition that the WTRU is intended to receive the PSSCH and the PSSCH is configured for a broadcast transmission, decoding the PSSCH based on the decoding related information associated with the PSSCH and the resource reservation information associated with the PSSCH obtained from the first part of the SCI.

11. The method of claim 10 comprising:

determining whether the WTRU has data to transmit on its PSSCH;

on a condition that the WTRU has the data to transmit on its PSSCH, performing resource selection based on the decoded first part of the SCI comprising the resource reservation information and the data QoS information, wherein the resource selection is performed by excluding resources indicated by the first part of the SCI.

12. The method of claim 10, wherein a determination of whether the WTRU is intended to receive the second part of the SCI is based on a parameter included in the decoded first part of the SCI.

13. The method of claim 10, comprising measuring and storing a physical sidelink shared channel- reference signal received power (PSSCH-RSRP) value and a sidelink receive strength signal indicator (S- RSSI) value for resource selection.

14. The method of claim 10, wherein the first part of the SCI is a broadcast transmission, a unicast transmission or a groupcast transmission, wherein

15. The method of claim 10, wherein the second part of the SCI is piggybacked on a PSSCH transmission.