WO2019160967A1

WO2019160967A1 - Co-existence for new radio (nr) operation in unlicensed bands

Info

Publication number: WO2019160967A1
Application number: PCT/US2019/017867
Authority: WO
Inventors: Ahmad Reza HEDAYAT; Shahrokh Nayeb Nazar; Erdem Bala; Rui Yang
Original assignee: IDAC Holdings Inc
Current assignee: IDAC Holdings Inc
Priority date: 2018-02-14
Filing date: 2019-02-13
Publication date: 2019-08-22
Anticipated expiration: 2020-08-14
Also published as: TW201937974A

Abstract

A wireless transmit/receive unit (WTRU) may perform, during a first time interval, a first listen-before-talk (LBT) process. When the first LBT is successful, a second LBT during a second time interval having grant free (GF) physical uplink shared channel (PUSCH) resources may be performed. The second LBT may be based on a selected random number of resource listen interval (RLI) symbols. The WTRU may transmit, when measured energy of reference signals (RSs) during the random number of RLI symbols is less than a threshold, second RSs up to a remaining number of RLI symbols.

Description

CO-EXISTENCE FOR NEW RADIO (NR) OPERATION IN UNLICENSED BANDS

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. App. No. 62/630,542 filed February 14, 2018 and U.S. App. No. 62/652,540 filed April 4, 2018, which are incorporated by reference as if fully set forth.

BACKGROUND

[0002] In wireless communication systems, a network may schedule wireless transmit receive units (WTRUs) individually for uplink (UL) transmissions or communication by assigning separate time, frequency, or code resources to each WTRU. As part of assigning resources, grants may be sent to WTRUs for UL transmission. In addition to assigned resources, the network may signal the presence of one or more time or frequency resources and allow WTRUs to use each resource for UL transmission without grants. Such grant free configurations is sometimes desirable.

SUMMARY

[0003] A network or wireless device may be configured for listen-before-talk (LBT) operation by comparing a level of energy detected across a bandwidth or band of an unlicensed or license- exempt wireless channel, frequency, or resource(s) to a pre-determined energy or power threshold to determine availability. If the network determines that the channel is idle for a period of time, the channel is accessed. The network or wireless device may also perform a LBT procedure by detecting an energy level within a resource listen interval (RLI) of a grant free (GF) physical uplink shared channel (PUSCFI) resource(s) and compare the detected energy level to a detected energy or power threshold to determine availability.

BRIEF DESCRIPTION OF THE DRAWINGS

[0004] Furthermore, like reference numerals in the figures indicate like elements, and wherein:

[0005] FIG. 1A is a system diagram illustrating an example communications system in which one or more disclosed embodiments may be implemented;

[0006] 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; [0007] FIG. 1 C 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. 1A according to an embodiment;

[0008] 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;

[0009] FIG. 2 is an example of channel occupancy time (COT) for new radio unlicensed (NR-U) operation;

[0010] FIG. 3 is another example of a COT for NR-U operation;

[001 1] FIG. 4 is an example of a grant free (GF) physical uplink shared channel (PUSCFI) resource(s) that includes a listen interval;

[0012] FIG. 5 is another example of a GF PUSCFI resource(s) that includes a listen interval;

[0013] FIGs. 6 and 7 are flow diagrams for two stage or step listen-before-talk (LBT) for GF UL transmission during a COT;

[0014] FIG. 8 is an example of two stage LBT;

[0015] FIG. 9 is an example of a GF PUSCFI resource(s) that includes a listen interval at the beginning of the resource(s);

[0016] FIG. 10 is an example of a GF PUSCFI resource(s) and includes a mini-slot of 7 symbols;

[0017] FIG. 1 1 is an example of multiple GF PUSCFI resources;

[0018] FIG. 12 is an example of multiple GF PUSCFI resources where each GF PUSCFI may have a resource listen interval (RLI) with a different size;

[0019] FIG. 13 is an example procedure for transmitting in a set of GF resources;

[0020] FIG. 14 is a diagram of a NR slot that includes a RLI resource sensing interval and a GF PUSCFI resource(s); and

[0021] FIG. 15 is a procedure for parallel operation of two sensing procedures.

DETAILED DESCRIPTION

[0022] 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 system 100 may employ one or more channel access methods, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single-carrier FDMA (SC-FDMA), zero-tail unique-word discrete Fourier transform Spread OFDM (ZT-UW-DFT-s-OFDM), unique word OFDM (UW-OFDM), resource block-filtered OFDM, filter bank multicarrier (FBMC), and the like.

[0023] As shown in FIG. 1A, the communications system 100 may include wireless transmit/receive units (WTRUs) 102a, 102b, 102c, 102d, a radio access network (RAN) 104, a core network (ON) 106, a public switched telephone network (PSTN) 108, the Internet 1 10, and other networks 1 12, 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 (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 Wi-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.

[0024] The communications system 100 may also include a base station 1 14a and/or a base station 1 14b. Each of the base stations 1 14a, 1 14b 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, the Internet 1 10, and/or the other networks 112. By way of example, the base stations 1 14a, 1 14b may be a base transceiver station (BTS), a Node-B, an eNode B, a Flome Node B, a Flome eNode B, a next generation nodeb (gNB), a new radio (NR) NodeB, a site controller, an access point (AP), a wireless router, and the like. While the base stations 1 14a, 1 14b 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. [0025] The base station 114a may be part of the RAN 104, 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, or the like. The base station 1 14a and/or the base station 1 14b 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 1 14a may be divided into three sectors. Thus, in one embodiment, the base station 1 14a 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.

[0026] The base stations 1 14a, 1 14b may communicate with one or more of the WTRUs 102a, 102b, 102c, 102d over an air interface 1 16, 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 1 16 may be established using any suitable radio access technology (RAT).

[0027] 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 1 14a in the RAN 104 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 16 using wideband CDMA (W-CDMA). W-CDMA may include communication protocols such as High-Speed Packet Access (HSPA) and/or Evolved HSPA (FISPA+). HSPA may include High-Speed Downlink (DL) Packet Access (FISDPA) and/or High-Speed Uplink (UL) Packet Access (HSUPA).

[0028] In an embodiment, the base station 1 14a 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 1 16 using Long Term Evolution (LTE) and/or LTE-Advanced (LTE-A) and/or LTE-Advanced Pro (LTE-A Pro). [0029] In an embodiment, the base station 1 14a 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 NR.

[0030] In an embodiment, the base station 1 14a and the WTRUs 102a, 102b, 102c may implement multiple radio access technologies. For example, the base station 1 14a 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 communications sent to/from multiple types of base stations (e.g., an eNB and a gNB).

[0031] In other embodiments, the base station 1 14a and the WTRUs 102a, 102b, 102c may implement radio technologies such as Institute of Electrical and Electronics Engineers (IEEE)

802.1 1 (i.e., Wireless Fidelity (Wi-Fi), 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.

[0032] The base station 1 14b in FIG. 1 A may be a wireless router, Flome Node B, Flome 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 802.1 1 to establish a wireless local area network (WLAN). In an embodiment, the base station 1 14b 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 1 14b and the WTRUs 102c, 102d may utilize a cellular-based RAT (e.g., W-CDMA, cdma2000, GSM, LTE, LTE-A, LTE-A Pro, NR etc.) to establish a picocell or femtocell. As shown in FIG. 1A, the base station 1 14b may have a direct connection to the Internet 1 10. Thus, the base station 1 14b may not be required to access the Internet 1 10 via the CN 106.

[0033] The RAN 104 may be in communication with the CN 106, 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 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 and/or the CN 106 may be in direct or indirect communication with other RANs that employ the same RAT as the RAN 104 or a different RAT. For example, in addition to being connected to the RAN 104, which may be utilizing a NR radio technology, the CN 106 may also be in communication with another RAN (not shown) employing a GSM, UMTS, CDMA 2000, WiMAX, E-UTRA, or WiFi radio technology.

[0034] The CN 106 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 1 12. The PSTN 108 may include circuit-switched telephone networks that provide plain old telephone service (POTS). The Internet 1 10 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 other networks 1 12 may include wired and/or wireless communication networks owned and/or operated by other service providers. For example, the other networks 1 12 may include another CN connected to one or more RANs, which may employ the same RAT as the RAN 104 or a different RAT.

[0035] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communications system 100 may include multi-mode capabilities (e.g., the WTRUs 102a, 102b, 102c, 102d may include multiple transceivers for communicating with different wireless networks over different wireless links). For example, the WTRU 102c shown in FIG. 1A may be configured to communicate with the base station 114a, which may employ a cellular-based radio technology, and with the base station 1 14b, which may employ an IEEE 802 radio technology.

[0036] 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 subcombination of the foregoing elements while remaining consistent with an embodiment.

[0037] The processor 1 18 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 Array (FPGA) circuits, any other type of integrated circuit (1C), a state machine, and the like. The processor 1 18 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 1 18 may be coupled to the transceiver 120, which may be coupled to the transmit/receive element 122. While FIG. 1 B depicts the processor 1 18 and the transceiver 120 as separate components, it will be appreciated that the processor 1 18 and the transceiver 120 may be integrated together in an electronic package or chip.

[0038] The transmit/receive element 122 may be configured to transmit signals to, or receive signals from, a base station (e.g., the base station 1 14a) over the air interface 1 16. 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.

[0039] 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 1 16.

[0040] 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 802.1 1 , for example.

[0041] 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 1 18 may also output user data to the speaker/microphone 124, the keypad 126, and/or the display/touchpad 128. In addition, the processor 1 18 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), readonly 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 1 18 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).

[0042] The processor 1 18 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.

[0043] 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 1 16 from a base station (e.g., base stations 1 14a, 1 14b) 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.

[0044] 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, a humidity sensor or the like.

[0045] 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, simultaneous, or the like. 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 1 18). In an embodiment, the WTRU 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)).

[0046] FIG. 1 C 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.

[0047] 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 1 16. 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.

[0048] 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. 1 C, the eNode-Bs 160a, 160b, 160c may communicate with one another over an X2 interface.

[0049] The CN 106 shown in FIG. 1 C 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.

[0050] 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 W-CDMA.

[0051] 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.

[0052] 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 1 10, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices.

[0053] 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 landline 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.

[0054] 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.

[0055] In representative embodiments, the other networks 1 12 may be a WLAN.

[0056] 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 802.1 1 e DLS or an 802.11 z 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 also be referred to as an“ad-hoc” mode of communication. [0057] When using the 802.1 1 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 set 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 802.1 1 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.

[0058] 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.

[0059] Very High Throughput (VHT) STAs may support 20 MHz, 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, or 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).

[0060] Sub 1 gigahertz (GHz) modes of operation are supported by 802.1 1 af and 802.1 1 ah. The channel operating bandwidths, and carriers, are reduced in 802.1 1 af and 802.1 1 ah relative to those used in 802.1 1 h, and 802.1 1 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, 802.1 1 ah may support Meter Type Control/Machine-Type Communication (MTC), 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). [0061] WLAN systems, which may support multiple channels, and channel bandwidths, such as 802.1 1 h, 802.1 1 ac, 802.1 1 at, and 802.1 1 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, due to a STA, such as 1 MHz operating mode STA transmitting to the AP, whole frequency bands may be considered busy even though a majority of frequency bands remain idle and may be available.

[0062] In the United States, the available frequency bands, which may be used by 802.1 1 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 802.1 1 ah is 6 MHz to 26 MHz depending on the country code.

[0063] FIG. 1 D 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 NR radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 1 16. The RAN 104 may also be in communication with the CN 106.

[0064] The RAN 104 may include gNBs 180a, 180b, 180c, though it will be appreciated that the RAN 104 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 1 16. In one embodiment, the gNBs 180a, 180b, 180c may implement MIMO technology. Also, in an example, gNBs 180a, 180b, 180c may utilize beamforming to transmit signals to and/or receive signals from the WTRUs 102a, 102b, 102c. 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 CCs (not shown) to the WTRU 102a. A subset of these CCs may be on unlicensed spectrum while the remaining CCs 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 communications from gNB 180a and gNB 180b (and/or gNB 180c). [0065] The WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using communications associated with a scalable numerology. For example, the OFDM symbol spacing and/or OFDM subcarrier spacing (SOS) may vary for different communications, different cells, and/or different portions of the wireless communication 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).

[0066] 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.

[0067] 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. 1D, the gNBs 180a, 180b, 180c may communicate with one another over an Xn interface.

[0068] The CN 106 shown in FIG. 1D may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one Session Management Function (SMF) 183a, 183b, and possibly a Data Network (DN) 185a, 185b. While each of the foregoing elements is 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. [0069] The AMF 182a, 182b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 104 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 protocol data unit (PDU) sessions with different requirements), selecting a particular SMF 183a, 183b, management of the registration area, termination of non-access stratum (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 ultrareliable low latency communication (URLLC) access, services relying on enhanced massive mobile broadband (eMBB) access, services for MTC access, or the like. The AMF 182a, 182b may provide a control plane function for switching between the RAN 104 and other RANs (not shown) that employ other radio technologies, such as LTE, LTE-A, LTE-A Pro, and/or non-third generation partnership project (3GPP) access technologies such as WiFi.

[0070] The SMF 183a, 183b may be connected to an AMF 182a, 182b in the CN 106 via an N1 1 interface. The SMF 183a, 183b may also be connected to a UPF 184a, 184b in the CN 106 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 WTRU 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.

[0071] The UPF 184a, 184b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 104 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 multihomed PDU sessions, handling user plane QoS, buffering DL packets, providing mobility anchoring, and the like.

[0072] The CN 106 may facilitate communications with other networks. 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 1 12, 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 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.

[0073] In view of FIGs. 1 A-1 D, and the corresponding description of FIGs. 1 A-1 D, one or more, or all, of the functions described herein with regard to one or more of: WTRU 102a-d, Base Station 1 14a-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.

[0074] 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 perform testing using over-the-air wireless communications.

[0075] 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.

[0076] Third Generation Partnership Project (3GPP) New Radio (NR) may be configured for URLLC, MTC, massive (mMTC), eMBB, or the like communication. URLLC may allow devices and machines to communicate with ultra-reliability, very low latency and high availability, making it potentially desirable for vehicular communication, industrial control, factory automation, remote surgery, smart grids, safety, public safety applications, emergency management, or the like. MMTC may apply to communication between devices that are low-cost, very large in number, battery- driven, or the like for applications such as smart metering, logistics, field sensors, body sensors, or the like. eMBB may enhancement parameters such as data rate, delay, coverage, or the like of mobile broadband access.

[0077] In unlicensed or license-exempt bands, a gNB or WTRU may be configured for listen- before-talk (LBT) operation before accessing an unlicensed band, channel, frequency, resource(s), code, or the like. Depending on requirements of the unlicensed channel, LBT operation may differ. In the examples given herein, requirements of the unlicensed channel may be set in part by regulator, government, private, pseudo government, military, standards development organization (SDO), or the like entity. A LBT procedure may include a fixed or random-duration interval where a network device or WTRU listens to a medium or waits to access a medium and if the energy level detected from the medium is more than a threshold or limit, the gNB or WTRU will refrain from transmitting. Otherwise, the wireless device or network device may transmit after completion of the LBT procedure.

[0078] In certain configurations, when detected energy level is less than the detected energy or power threshold or limit, a network device may conclude that a grant free (GF) physical uplink shared channel (PUSCH) resource(s) is available and prepares for communication of data or a transport block (TB) in the GF PUSCH resource(s).

[0079] In the examples given herein, LBT and resource listen interval (RLI) sensing may be utilized together. A WTRU may also utilize a reference signal (RS) during a RLI to determine usage by another WTRU. A WTRU may also utilize the detected energy during a LBT operation or listen interval and discount the energy collected from one or more prior known resource elements or blocks.

[0080] NR may be configured with numerologies with subcarrier spacing ranging from 15 kHz to 240 kHz. The base subcarrier spacing may be 15 kHz, and other numerologies may have increasing subcarrier spacing with a multiplication of a power of two. An example of base subcarrier spacing is provided in Table 1.

Table 1 [0081] A physical downlink control channel (PDCCH) may include one or more control-channel elements (CCEs). The number of CCEs may depend on aggregation level or a predetermined parameter. A control-resource set (CORESET) may include

resource blocks in the frequency domain, given by a higher-layer message or a parameter such as CORESET-freq-dom. A CORESET may also include A¾^ESET e {1,2,3} symbols in the time domain, given by a higher-layer message or a parameter such as CORESET-time-dur [1] In certain scenarios, a group-common (GC) PDCCH and a common PDCCH may be configured. The GC PDCCH may be configured by a higher-layer message, a radio resource control (RRC) message, or the like. The common PDCCH may be used to provide system information and paging for a group, cluster, or associated WTRUs within an area. Remaining system information (RMSI) and other system information (OSI) may be configured by the physical broadcast channel (PBCH).

[0082] A physical uplink control channel (PUCCH) may be configured for multiple formats. Example formats are provided in Table 2.

Table 2

[0083] Table 3 shows an exemplary structure for symbols and slots of various formats. OFDM symbols in a slot may be classified as downlink (denoted D in Table 3), flexible (denoted X in Table 3), or uplink (denoted U in Table 3).

Table 3

[0084] LBT may be desirable for unlicensed or license-exempt bands, channels, frequencies, resources, codes, or the like. In certain configurations, category 1 (CAT1 ) operation may have no listen interval, category 2 (CAT2) may have a fixed duration listen interval, category 3 (CAT3) may have a random duration listen interval with a fixed contention window, category 4 (CAT4) may have a random duration listen interval with increasing contention window, or the like. For LBT CAT4, a network device, WTRU, or the like may want to transmit control information or data in an unlicensed or license-exempt channel. The device may perform an initial clear channel assessment (CCA), where the device may determine whether the channel is idle for a period of time, a time interval, a sum of a fixed period of time and a pseudo-random duration, or the like. Channel or resource(s) availability may be determined by comparing the level of energy detected (ED) across the bandwidth or band of the unlicensed channel or frequency to an energy or power threshold. The energy or power threshold may be determined by a regulator, government, private, pseudo government, military, standards development organization (SDO), or the like entity.

[0085] If a channel is free or available, a communication or transmission may commence, proceed, or continue. If not, the device may conduct a random back-off procedure where a random number may be selected from a specified interval, contention window, or the like. Once a back-off countdown is obtained, a device may determine whether the channel is verified to be idle, and the transmission may be initiated when the back-off counter reaches zero or close to zero. If a network device gains access to the channel, it may be allowed to transmit for a duration, interval, channel occupancy time (COT), or the like. A communication or transmission may then occur for a limited duration, maximum COT (MOOT), opportunity time, or the like. A CAT4 LBT procedure with random backoff and variable contention window sizes may be a desirable channel access and co-existence configuration with Wi-Fi, 802.1 1x, LTE, other RATs, other LAA networks, or the like.

[0086] A carrier bandwidth part may be a contiguous set of physical resource blocks, selected from a contiguous subset of the common resource blocks for a given numerology on a given carrier or the like. In certain configurations, a WTRU may be configured with up to four carrier bandwidth parts (BWPs) in the DL with a single DL carrier BWP being active at a given time. A WTRU may not be expected to receive a physical downlink shared channel (PDSCH), a PDCCH, channel state information reference signal (CSI-RS), timing reference signal (TRS), or the like outside an active BWP. In certain configurations, a WTRU may be expected to receive a PDSCH, a PDCCH, a CSI- RS, a TRS, or the like in an active BWP.

[0087] A WTRU may be configured with up to four carrier BWPs in the UL with a single UL carrier BWP being active at a given time. If a WTRU is configured with a supplementary UL, the WTRU may be configured with up to four carrier BWPs in the supplementary UL with a single supplementary UL carrier BWP being active at a given time. In certain configurations, the WTRU may not transmit the PUSCH or the PUCCH outside an active BWP or the WTRU may transmit the PUSCH or the PUCCH in an active BWP.

[0088] Two demodulation RS (DM-RS) configurations may be utilized for an OFDM waveform to multiplex multiple antenna ports in the downlink. For certain configurations, in the uplink each layer of each transmitting WTRU may be considered as one antenna port. In configuration 1 , the DM-RS corresponding to one antenna port may be transmitted in every other subcarrier. The DM-RS corresponding to another antenna port may be transmitted on the same subcarriers but the two DM- RS sharing the subcarriers may be generated by applying different cyclic shifts to a same mother or seed sequence. If there is an additional OFDM symbol, time domain spreading may be used to increase the number of antenna ports to 4. Another set of 4 antenna ports may be supported on the unused subcarriers, resulting in 8 orthogonal antenna ports over 2 OFDM symbols. As an example, DM-RS coefficients corresponding to 4 antenna ports over 2 OFDM symbols may be:

Antenna port 1 : r_k; r_k

Antenna port

Antenna port 3: w_k; -w_k

Antenna port

where r_k and w_k are the coefficients from two different mother sequences, a and b are cyclic shift parameters, and N is the sequence length. In the case of a DFT-s-OFDM waveform, a combination of cyclic shifts and time domain spreading may be used to multiplex antenna ports.

[0089] In configuration 2, up to 4 antenna ports may be multiplexed on two adjacent subcarriers and two OFDM symbols using time and frequency domain spreading. In this configuration, cyclic shifts of sequences may not be used. As an example, the DM-RS coefficients corresponding to 4 antenna ports over 2 subcarriers and 2 OFDM symbols may be:

Antenna port 1 : [r_k; r_k] [ r_k ; r_k]

Antenna port 2: [w_k; —w_k] [ w_k ; — w_k]

Antenna port 3: [ p_k ; p_k\ [- p_k ; -p_k\

Antenna port 4: [ q_k ; -q_k] [- q_k ; +q_k\

where r_k, w_k, p_k, q_k are DM-RS coefficients and the first pair may represent the transmitted coefficients over two adjacent subcarriers while the second pair may represent the transmitted coefficients over two adjacent OFDM symbols. In configuration 2, a WTRU may use 2 subcarriers out of 6 subcarriers, resulting in a total of 12 orthogonal antenna ports over 2 OFDM symbols. [0090] For OFDM waveforms, the DM-RS may be generated by QPSK modulation of pseudorandom (PN) sequences that may be a length-31 Gold sequence. The initialization of the second m- sequence may be different for different antenna ports, resulting in different sequences. Correspondingly, the PN sequences used by two WTRUs may be similar or different depending on the initialization of the shift registers that generate the PN sequences.

[0091] When a new radio unlicensed (NR-U) device attempts to access an unlicensed or license- exempt channel, frequency, resource(s), or code it may compete with inter-RAT devices and intra- RAT devices for access. The type and density of inter-RAT devices may depend on the unlicensed channel and may be Wi-Fi, 802.1 1x, LTE LAA, Bluetooth®, or the like devices. Intra-RAT devices may be other NR-U, LTE unlicensed, or the like devices such as WTRUs, network devices, gNBs, or the like. For example, for an NR-U WTRU, an intra-RAT device may be other NR-U WTRUs that are connected to the same gNB or NR-U gNB or WTRUs that are not associated with the same gNB. Both inter-RAT and intra-RAT devices may be sources of interference or noise.

[0092] In attempting to access an unlicensed channel by an NR-U WTRU, gNB, or other device, fair competition or co-existence with inter-RAT and intra-RAT devices may be desirable. For fair competition or co-existence, a wireless device may need to first perform a LBT operation for a duration of time prior to access of an unlicensed channel, frequency, resource(s), code, or the like. In certain configurations, if energy is less than a threshold during that time, the wireless device may be allowed to transmit in the wireless channel for up to a maximum duration.

[0093] NR-U devices may interact differently with inter-RAT and intra-RAT devices. For coexistence among inter-RAT devices, presence or activity awareness of an inter-RAT device may be achieved by measuring the level of energy emitted by such devices. In example for LBT, an NR-U device may listen to the channel for a time duration, and, if no energy beyond a threshold is detected, then the NR-U device may be allowed to transmit in the wireless channel for up to a maximum duration or interval. For co-existence with intra-RAT devices, while energy-detection- based LBT may be configured, it may also be possible to perform such procedure more efficiently or robustly since competing devices may also have awareness of other waveforms.

[0094] For an NR-U device, competing devices in an unlicensed band may be categorized as inter-RAT devices; NR-U gNBs, NR-U WTRUs, intra-RAT devices, or the like that belong to competing entities or operators; and NR-U gNBs, NR-U WTRUs, intra-RAT devices, or the like that belong to the same entity or operator. For inter-RAT devices, a device may primarily detect usage of the unlicensed channel using energy detection. For NR-U gNBs or WTRUs that belong to competing entities or operators, detection of usage of the unlicensed channel may be performed by detecting some of the NR-U signaling within a similar numerology, such as channel bandwidth or carrier spacing. For NR-U gNBs or WTRUs that belong to the same entity or operator, detection of usage of the unlicensed channel may similarly be performed by detecting some of the NR-U signaling within a similar numerology. Moreover, such NR-U gNBs may cooperate with each other to enhance channel sharing by exchanging some information with each other, such as the load of each NR-U gNB, the urgency of channel access and channel prioritization among such NR-U gNBs, or the like.

[0095] FIG. 2 is an example of channel occupancy time (COT) for new radio unlicensed (NR-U) operation 200. In 200, each PUSCFI may be grant-based (GB), configured grant, GF, or the like and a NR-U network device may access the channel after successfully performing a LBT procedure or operation on the network side. A network device that establishes or configures a COT may compete with inter-RAT devices, other NR-U devices, or the like. An NR-U WTRU that is connected or coupled with an NR-U gNB that already established a COT may additionally compete with the peer NR-U WTRUs that are connected or coupled with the same gNB. Once a COT is established, a WTRU may be configured to transmit.

[0096] The PUSCFI for GB access may be assigned to a particular WTRU that is informed via a preceding PDCCFH, short PDCCFI (sPDCCFI), a control channel, or the like. For this configuration, the WTRU may not compete with other WTRUs that are connected with a network device, gNB, or the like. In this configuration, a WTRU may perform LBT for a fixed duration, such as a CAT2 device, or with a random back-off or delay, such as a CAT3 or CAT4 device. Flowever, if the channel is not idle and LBT unsuccessful, the WTRU may be unable to transmit at the PUSCH resource(s) or resource block (RB) assigned for the GB access. Accordingly, the resource(s) may be left unused, which may be undesirable or inefficient.

[0097] GF access may also be configured for the PUSCH for multiple WTRUs that are assigned. One or more WTRUs may be informed via RRC configuration, RRC messaging, a higher layer signal, a preceding PDCCH, or the like for GF access. For this configuration, since a WTRU may compete with other WTRUs that are connected or coupled to a network device, LBT may be needed or desirable to coexist with external competitors, such as inter-RAT devices as well as intra-RAT devices that are not connected with the same network device, and internal competitors, such as WTRUs that are also allowed to use the GF resources. In LBT, at least one WTRU may successfully perform LBT and gets the chance to transmit on the PUSCH resource(s) assigned for a GF communication or transmission. However, it is also possible that more than one WTRU may, after a successful LBT procedure, attempt to transmit on the GF or configured grant resource(s) resulting in a collision, conflict, contention, or the like. [0098] Examples are given herein that may balance efficiency, collision risk, contention, or conflict for UL channel access in one or more GF resources. In some examples, a two-stage or two- step LBT procedure may be configured. A device may first perform a regulatory-required LBT such that a fair co-existence with other RAT devices may be achieved. A WTRU may perform this part of the LBT procedure with a fixed or predetermined listen interval. LBT categories or configurations with variable-length may also be configured. When a WTRU attempts to use a GF or GB interval with a variable-length listen interval, the WTRU may calculate the listen interval in advance such that the WTRU may perform an energy detection procedure for substantially the listen interval before attempted to utilize the GF or GB uplink resource(s).

[0099] FIG. 3 is another example of a COT for NR-U operation 300. In 300, each PUSCH may be configured as GF. Each GF PUSCH resource may be configured with a listen interval, RLI, or the like before or substantially at the beginning of the resource(s) that may be one or more OFDM symbols (OSs). In an example, one of the multiple NR-U WTRUs that are connected with the same network device and configured to access the same GF resource(s) may eventually access the GF resource(s) while avoiding a collision(s) or conflict(s) with other WTRUs. In 300, a network device may access the channel after successfully performing a LBT procedure or operation.

[0100] A RLI may include one or more symbols or have similar frequency duration as a PUSCH resource(s). The size of a RLI may differ from one resource to another and may be determined by a network device. A WTRU that is configured to access a GF resource(s) may also be configured with the size of the RLI that is obtained from a RRC configuration, RRC message, RRC signaling, a higher layer message, a DCI indication, a COT indicator configured before or at the beginning of a COT, or the like. The COT indicator may indicate the size of each RLI, the size of the RLI for each group of GF resources, the size of RLI for one or more GF resources within the COT, or the like. The size of a RLI may be based on how many WTRUs are configured to attempt to use a GF resource(s), the duty cycle of the WTRUs configured to use the resource(s), or the like. In an example, since the duration of a slot may be 14 symbols and the duration of PUSCH resources may also be up to 14 symbols, the duration of a RLI may be adjusted or managed to keep the LBT procedure efficient or robust.

[0101] FIG. 4 is an example of a GF PUSCH resource(s) that includes a listen interval. In 400, the listen interval may comprise one or more OFDM symbols. The number of OFDM symbols may be indicated by RLI 402. A WTRU that is configured to access a GF resource(s) may attempt to perform energy or power detection at a starting or beginning portion of the RLI. The starting portion of the RLI that is chosen for sensing may be up to substantially the entire duration of the RLI, such as up to X RLI OFDM symbols. The WTRU may randomly select a number from 0 to RLI, denoted as RLIWTRU. In a configuration, a RLIWTRU may be chosen from {0, 1 ,2, ..., RLI}. The WTRU may detect the energy or power level within the RLIWTRU interval and may compare the detected energy to the threshold EDGFBW. If the detected energy is less than the threshold, the WTRU may determine that the GF resource(s) is available and prepare to transmit a pending or new data or TB on the GF resource(s).

[0102] A threshold or limit may be scaled according to the bandwidth of the RLI, the bandwidth of the GF PUSCH, or the like. For example, if the LBT threshold for one symbol and for the specified BWportion is EDBWP , the threshold used for a given RLI may be determined by Equation 1 :

EDGFBW = (L X GFBW/BWp₀rtion) ^x EDBWP Equation 1 where GFBW is the bandwidth of the GF resource(s) and the RLI and BWp_ortion is the bandwidth of the portion configured for the WTRU. Therefore, in certain configurations a WTRU that performs LBT on a GF resource(s) may compare the collected energy or power from the L OFDM symbols and compare it with EDGFBW. If EDBWP is expressed in dBm, then Equation 2 may be:

EDG_FBw(dBm) = 10 x logio(L x GFBW/BWportbn) + ED_BWp(dBm). Equation 2

[0103] In certain configurations, a WTRU may perform resource sensing using energy or power detection across the bandwidth of the RLI for the duration of L symbols, using cyclic-prefix detection, or the like. The WTRU may attempt to detect the presence of a cyclic-prefix by performing correlation or auto-correlation of the received signal, for the bandwidth of the RLI, with the delayed version of the same signal. The amount of the delay may be obtained from the numerology and the length of the cyclic prefix. For example, if the OFDM symbol duration is TOFDM and the duration of the cyclic-prefix is TCP, then the delay may be equal to TOFDM + TOP. In certain configurations, a WTRU may select to monitor multiple numerologies or multiple cyclic-prefix lengths and compare energy to a scaled version of EDGFBW.

[0104] For a WTRU listen interval configured as length L, energy, power, or signal detection for the starting portion of the GF resource(s) for that duration may be performed. If the detected level of energy or power is less than a threshold or limit, the WTRU may assume the GF resource(s) is available and may prepare to transmit data or a TB in the GF resource(s). A WTRU may prepare pending data or a TB for the remaining portion of the RB and include the remaining symbols of RLI for communication or transmission. In certain configurations, a WTRU may be unable to prepare pending data or a TB for the remaining portion of the resource block due to time constraints or there may be redundancy-value (RV) ambiguity such that a network device may be unable to decode the data or TB. In such cases, the WTRU may send a signal, a reservation signal, a RS, DM-RS, or the like for the remaining symbols of the RLI. After the signal or reservation signal, the WTRU may send prepared pending data or a TB during the remaining portion of the resource block that may be the portion of the resource block that excludes the RLI. The reservation signal, signal, RS, or DM-RS may be a prepared symbol for the bandwidth of the GF resource(s) or it may be any signal but with a similar power as the power that the WTRU may use during transmission over the GF resource(s).

[0105] A WTRU may be configured to select, or configured by the network, a communication or transmission operation after a listen interval. In certain configurations, a network device may not attempt to detect any signal during the RLI. In certain configurations, a network device may attempt to detect a signal and a TB from the first symbol of the RLI. In certain configurations, A WTRU may select value zero for a listen interval L that may lead to sending a pending TB(s) without any resource sensing. Here, a WTRU may randomly select the listen interval L = 0. A zero duration listen interval or no resource sensing may occur before the start of the GF resource(s). In certain configurations, this may occur far enough in advance such that the WTRU has time to prepare for transmission.

[0106] A WTRU may be configured to select a listen interval L = 0 due to a higher or low priority given to the WTRU by the network or the WTRU may be configured to use the resource(s) in a GB manner. In this configuration, a network device or gNB may assign a resource(s) for both GB and GF operation where, if the WTRU that is configured to use the zero duration listen interval has pending data or a TB and starts to transmit in the resource(s), then other WTRUs that are configured to use a non-zero duration listen interval may defer communication or transmission. If a WTRU configured to use the zero duration listen interval with no pending data or a TB(s) and does not transmit any signal in the resource(s), then the other WTRUs that are configured to use a nonzero duration listen interval may have an opportunity to use the resource(s). This may allow for a mixed operation for GF and GB where a WTRU with higher priority or a URLLC WTRU may be given zero duration listen interval, L=0, and other WTRUs with GF configurations may be allowed to select a non-zero listen interval such as a value from 1 to D.

[0107] A network device or gNB may configure WTRUs with specific or custom listen intervals, assign pre-determined values of RLIWTRU to each WTRU, set a prioritization order among WTRUs, or the like. A WTRU with RLIWTRU = 0 may be designated with the highest priority. WTRUs that are configured with smaller RLIWTRU values may be prioritized over larger RLIWTRU values. A WTRU may transmit during a GF PUSCH after a successful LBT if other WTRUs with smaller RLIWTRU values do not transmit during the resource(s). Referring again to FIG. 4, a GF may span several NR slots. In certain configurations, a single RLI may also serve as a listen interval for a GF UL or PUSCH resource(s) that spans more than one slot. This may desirably help efficiency as the listen interval versus the entire duration of the uplink resource(s) may increase.

[0108] FIG. 5 is another example of a GF PUSCFI resource(s) that includes a listen interval. A listen interval may resolve contention for this resource and the next several GF resources, which may or may not be consecutive, sequential, or the like. For example, a RLI 502 at the beginning of a GF PUSCFI or UL resource(s) may serve as the listen interval of multiple consecutive GF PUSCFI or UL resources 504. In a K repetition GF communication or transmission, a RLI at the beginning of the first resource may serve as the listen interval of the K consecutive GF PUSCFI or UL resources. A WTRU that performs the second step of the LBT and wins the contention may continue transmitting according to the K-repetition GF PUSCFI or UL for the next K-1 GF resources. This may occur within a same COT and after the first part of LBT is successful.

[0109] In 500, a WTRU may perform the first step of LBT, such as based on a LBT procedure of CATs 1 -4, and perform the second step of LBT, using the RLI at the beginning of a first resource, and for the next K-1 resources the WTRU may skip performing first and/or the second step(s) of LBT. Thus, in certain configurations just the first step of the LBT according to a LBT category, that may be the same as the LBT procedure performed in the first step for the first resource or may be a fixed-duration LBT procedure such as CAT1 and CAT2, may be performed. In certain configurations, a WTRU may perform the second step of the LBT for the first resource and not win the contention, such as since the energy detected during the listen interval within the RLI is above the threshold. For this scenario, the WTRU may not attempt to access the next K-1 GF resources and may wait for the next set of K GF resources for transmission. In other configurations, the WTRU may attempt the second step of the LBT prior to any of the K GF resources, until successful for one of them (i.e. the i-th resource) without performing the second step for the remaining K-1 GF resources.

[01 10] In certain configurations, RLI may decrease or reduce the chance of more than one WTRU accessing the PUSCFI or UL resource(s) that collision, conflicts, contention, or the like between WTRUs occur. This may be due to two or more WTRUs selecting similar listen interval values. In certain configurations, collision or conflicts may also occur due to a hidden node where a WTRU does not detect the signal transmitted during the RLI by another WTRU that started communication or transmission earlier on a similar resource(s). To reduce the chance of collision in the subsequent attempt, a WTRU that does not receive hybrid automatic repeat request (FIARQ) feedback or FIARQ-negative acknowledgement (NACK) feedback for data or a TB sent on an earlier GF PUSCFI or UL resource(s), for the subsequent attempt to access a GF UL resource(s), the WTRU may select a listen interval larger than the listen interval of the previous PUSCH or UL transmission. The WTRU may also select the largest listen interval equal to the RLI, skip the subsequent GF PUSCH or UL resource(s), skip a fixed number of subsequent GF UL resources, may skip a random number of subsequent GF PUSCH or UL resources, or the like to prevent collision or conflict. In certain configurations, a random number may be drawn from a range and distribution that is specified or configured by the network or gNB. If the WTRU received a HARQ- NACK for previously sent data or a TB indicating the network is able to retrieve the identification of the WTRU from the collided signals within the GF resource, the WTRU may also receive a GB uplink resource(s) to retransmit the pending data or TB.

[01 1 1] FIGs. 6 and 7 are flow diagrams for two stage or step LBT for GF PUSCH or UL transmission during a COT. As explained further herein, in 600 a WTRU may obtain attributes and the RLI to access GF resources (602). A TB may be prepared for sending in a next GF resource(s) and the first stage or step of LBT using LBT category may be performed (604). If LBT is successfully performed (606), a listen interval RLIWTRU may be pseudo randomly chosen from {0, ...,RLI} and EDGFBW calculated using the GF resource(s) BW and EDBWP (610). Otherwise, transmission may be abandoned for the GF resource(s) (608) and a TB may be prepared for sending in a next GF resource(s) and the first stage or step of LBT using LBT category may again be performed (604).

[01 12] Energy detection may be performed for listen interval RLIWTRU and determined if less than a threshold or limit (612). If yes, the TB is transmitted or communicated after RLIWTRU or a reference or reservation signal is transmitted from RLIWTRU until RLI and the TB is transmitted after RLI (614). Otherwise, transmission may be abandoned for the GF resource(s) (608). In other configurations, instead of abandoning the GF resources, irrespective of LBT failure the WTRU may still start transmission at a fixed OFDM symbol of the GF PUSCH.

[01 13] In certain configurations, the RLI region may be configured immediately before a GF resource(s) such that the structure of a PUSCH or UL resource(s), RSs, DM-RS signals, or the like may be unaffected by the RLI region. A RLI region may also have a similar bandwidth as the GF resource(s) and the number of OFDM symbols of the RLI region may comprise the RLI. A WTRU may pseudo-randomly select a listen interval, up to RLI symbols, indicated by RLIWTRU. After performing a first LBT, the WTRU may perform RS detection or energy detection on the listen interval of RLIWTRU and if the detected level of energy is less than a threshold then the WTRU may assume that the medium is available, unoccupied, or not in use by another WTRU. For the remaining duration of the RLI and up to the beginning of the GF resource(s), a WTRU may be configured to send a reservation signal, RS, DM-RS, sounding reference signal (SRS), signal, or the like. Sending one of these signals may result in the RLI to be sensed as busy by other WTRUs or be perceived as being reserved by a WTRU.

[01 14] In certain configurations, each WTRU may transmit assigned DM-RSs during the interval after RLIWTRU and up to the beginning of the GF resource(s). The DM-RS may be repeated multiple times depending on the remaining duration or symbols of the RLI such that a channel is occupied up to the beginning of the GF PUSCH. Other WTRUs performing channel sensing and measuring the energy during their own RLIWTRU may find the detected level of power or energy higher than the threshold and refrain from transmission during the GF PUSCH.

[01 15] The communication or transmission of a RS, DM-RS, DM-RS sequence, SRS, or the like during the remaining symbols after RLIWTRU and up to the beginning of a GF PUSCH may be used by a WTRU to obtain a more reliable estimation of unlicensed channel, frequency, resource(s), band, or code availability. In certain configurations, WTRUs may be configured to use a similar PN sequence initialization parameter for the DM-RS sequence they transmit during the RLI duration. WTRUs may also be configured with or signaled such that a group or cluster of WTRUs may use a similar DM-RS sequence to allow multiplexing. Multiplexing of DM-RSs for different WTRUs may be achieved with time domain spreading, frequency domain spreading, cyclic shifts, frequency division multiplexing, or the like.

[01 16] WTRUs may be configured such that some, a group, or cluster may use different PN sequences. In this configuration, WTRUs may also be provided with the information about the set of the PN sequences, other types of sequences, Zadoff-Chu sequences, or the like. This configuration may improve RS detection by other WTRUs and to calculate reference signal received power (RSRP), reference signal received quality (RSRQ), or the like accurately.

[01 17] In another configuration, a WTRU may perform RS detection, DM-RS detection, or the like for each possible base sequence, and each possible RS multiplexing technique. RS multiplexing techniques may include time and frequency domain spreading, applying cyclic shifts, frequency domain multiplexing, spatial multiplexing, or the like. RS detection may be carried through any possible frequency domain, code domain, space domain, or the like. A WTRU may also utilize RS detection using a subset of these multiplexing techniques and a subset of the base sequences. During the transmission on the GF PUSCH, a WTRU may utilize a WTRU-specific sequence initialization parameter for DM-RS.

[01 18] In certain configurations, an assumption may be that a network device or gNB that successfully performed a LBT can transmit DL signals or channel within the unlicensed channel, frequency, band, or the like. A network or gNB may then transmit some DL signals such as DM-RS, CSI-RS, SRS, or the like during the period that the WTRU is performing LBT to access a GB or a GF resource(s). This may keep resources busy or occupied to pre-empt usage by others. For example, sending reference signals may prevent Wi-Fi or 802.11x communications by others. For a LBT procedure over the wider band, BWP, or the like the WTRU may perform RS detection and estimate the energy or power. This may be achieved by a matched filter to a specific sequence within the pool of DM-RS, SRS, CSI-RS, or the like sequences over the RBs or REs for which the gNB or network device does not transmit the said DL signals. A WTRU may be configured with RS attributes that the network device or gNB transmits on the said RBs or REs.

[01 19] A WTRU may compare collected energy or power to a modified threshold. The modified threshold may be applied to capture the actual bandwidth for which the energy is calculated. For example, this may be the nominal bandwidth minus the bandwidth used by the network device or gNB to transmit the said DL signals. This may also be equivalent to a WTRU that estimates the energy collected over the wider bandwidth minus the energy collected over the bandwidth for which the network device or gNB transmits the DL signals, and then comparing the result with the modified threshold. This configuration may be desirable if the network device or gNB transmits some DL signals, such as RSs, during the period that one or more WTRUs perform a LBT procedure, and the unlicensed channel is going to be reserved by the network device or gNB for that duration regardless of a successful LBT procedure at the WTRU side. A WTRU may be configured to determine that the operation of sending reference signals, such as DM-RS, is for GF LBT instead of grant based communication.

[0120] As explained further herein, in 700 a WTRU may be configured to use GF resources for UL transmission (702). The WTRU may obtain a set of resources and associated attributes such as the location and periodicity of the resources. The WTRU may also obtain the RLI for each GF resource or a set of resources. RLI may be obtained from a RRC configuration, RRC signal, RRC message, higher layer message, or the like as an attribute for each resource or a set of resources. RLI may also be obtained in DCI or a MCOT indicator announced at the beginning of a COT. The RLI may be used for the second step of LBT.

[0121] The WTRU may prepare to send a pending TB in a next GF resource(s) and perform the first step of LBT CAT 1 -4 (704). If the WTRU performs a fixed listen interval LBT, such as in CAT1 or CAT2, the WTRU may start performing the energy detection for the specified listen interval before the time of the GF resource(s). If the WTRU performs a fixed listen interval LBT, such as in CAT2, the WTRU may first calculate the listen interval for the specified category and attempts to perform energy or power detection for the duration of the calculated listen interval before approaching the GF resource(s). If the remaining time before the resource(s) is less than the listen interval, the WTRU may skip the resource(s).

[0122] If the first LBT procedure is performed successfully (706), the WTRU may pseudo- randomly select a listen interval duration from {0, ...,RU} in units of OFDM symbols and the WTRU calculates an energy detection threshold from a pre-specified or predetermined threshold (710). The energy detect threshold may also be scaled based on a bandwidth resource(s).

[0123] The WTRU may perform energy or power detection for the listen interval and if the detected energy or power is less than a threshold (712), the TB is transmitted or communicated by the WTRU in the remaining RLI and the part of the resource(s) after the RLI (714). The WTRU may also transmit a reservation signal for the remaining RLI and after the RLI transmits the TB at the part of the resource(s) after RLI. Otherwise, transmission may be abandoned for these resources and monitoring of the next GF resource(s) may be performed (708). The WTRU may then again prepare to send a pending TB in a next GF resource(s) and perform the first step of LBT CAT 1 -4 (704).

[0124] FIG. 8 is an example of two stage LBT 800. A stage may be a sub-stage, step, sub-step, process, sub-process, or the like. In 800, a configuration for a RLI and UL GF resources may be received (802). LBT using energy detection for a LBT category (804) may be performed and determination of a successful LBT made (806) as part of a first stage LBT. If successful, a second stage LBT is performed. Otherwise, transmission of a GF resource(s) may be abandoned (810) and LBT using energy detection for a LBT category (804) may be again performed.

[0125] If successful, second stage LBT may include pseudo-randomly selecting a RLIW_TRU from {0,...,RLI} (812), detect reference symbols or signals in the listen interval (814), perform measurements on reference symbols transmitted in the listen interval (816), and comparing the measurements to a threshold or limit (818). If greater than a threshold or limit, transmission of a GF resource(s) may be abandoned (810). If less than a threshold or limit, a reservation signal may be transmitted on the remaining symbols of the listen interval (820) and the TB transmitted on the GF resource(s) after the RLI (822).

[0126] FIG. 9 is an example of a GF PUSCH resource(s) that includes a listen interval before or at the beginning of the resource(s) 900. In 900, RLIW_TRU may comprise 3 symbols or up to RLI symbols 902, chosen randomly. The RLI symbols 902 of the listen interval may resolve contention or conflict for this GF resource(s) and forthcoming consecutive GF resources. In 900, a WTRU may perform reference signal or energy detection on listen interval RLIW_TRU. If the detected energy level or sequence likelihood is less than a threshold, the WTRU may determine the medium is not in use or available. For the remaining duration of the RLI up to the beginning or start of the GF resource(s), the WTRU may send a reservation signal, reference signal, DM-RS, SRS, or the like.

[0127] In certain configurations, instead of a WTRU backing off when the interference energy is above a threshold, it may back off when the interference energy due to transmission of a set of WTRUs is above a threshold. The interference from WTRUs that are outside a specified set of WTRUs configured to transmit on similar resources or GF resources may be considered for back-off. Interference from 802.1 1x, LTE, or other RATs on similar resources or GF resources may also be considered for back-off in this configuration.

[0128] In a configuration, a WTRU may measure the energy or power of a RS, DM-RS, SRS, or the like sequence that belongs to a set outside of a preferred set of sequences that the WTRU is configured with or associated. Based on the measurement, the WTRU may perform an action such as to consider the resource for transmission or skip the resource. The WTRU may determine that a set of RSs belong to a set of WTRUs that the network device or gNB grouped or clustered. A group or cluster may include WTRUs that are configured to be part of a multi-user MIMO (MU-MIMO) communication or transmission, WTRUs that are configured to participate in a non-orthogonal multiple-access for a same uplink resource(s), WTRUs that are configured to use a similar GF PUSCFI resource(s), or the like.

[0129] A network device may be able to separate the interfering signals of the WTRUs configured to use a similar GF resources. A network device may also be able to distinguish the energy that comes from a preferred set of sequences configured for the WTRU and the energy that comes from outside of the preferred set of sequences. For non-orthogonal multiuser/multi-access transmission, a base station may be able to separate the non-orthogonal transmission from a group or cluster of WTRUs.

[0130] In certain configurations, a group or cluster of WTRUs may be scheduled to transmit on similar resources, similar GF resources, or the like. The set of WTRUs scheduled to transmit on similar GF resources may have information pertaining to the generation of the RSs of all or some of the WTRUs in the set. As an example, all WTRUs in the set may be configured or signaled with a similar PN sequence initialization parameter such that all WTRUs will generate identical sequences for their DM-RS. The WTRUs in that set may also be configured or signaled the information that all WTRUs are going to use a similar DM-RS sequence. [0131] Since a WTRU may know the DM-RS sequence, DM-RS configuration, available DM-RS multiplexing techniques, or the like, it may determine if any one of the other WTRUs in the set are active by estimating the likelihood that a DM-RS, multiplexing pair, antenna port, or the like is active. Using DM-RS activity information, DM-RS signal strength information, or the like a WTRU may estimate the power of a received signal that may have been originated by network devices or WTRUs outside the set.

[0132] In another configuration, some or all WTRUs in a similar GF set may use sequences generated from different PN sequences but they may have sufficient information to deduce the set of sequences used by the WTRUs in the GF set. This may be achieved by configuring the WTRU with, or signaling to the WTRU, sufficient information about sequence generation parameters of the WTRUs. As an example, there may be a rule or configuration on generating the PN sequences known, stored, pre-configured, or the like to all or some of the WTRUs in the set.

[0133] Initialization of a PN sequence shift register may utilize the number C-H ., where C and L are constants known to the WTRUs in the set and k is a WTRU specific parameter that may be deduced by all WTRUs. For example, if k is between 1 and 12 and a WTRU is configured or signaled to use k = 3, a WTRU may know what other potential WTRUs may set their respective k. In addition to sequence generation, WTRUs may also need to know the mapping between the sequence index and multiplexing technique. This information may be configured, signaled, or derived by the WTRU from existing information. As an example, k may indicate the multiplexing technique.

[0134] FIG. 10 is an example of a GF PUSCFI resource(s) and includes a mini-slot of 7 symbols and RLIWTRU of 3 symbols 1002. Although 1000 shows a mini-slot of 7 symbols, a RLI may include a mini-slot with 2, 5, 7, or any number of symbols. In 1000, a WTRU may perform ED on the listen interval of RLIWTRU such as on the GF resource BW. If no or little energy is detected, the WTRU may determine the medium is not in use by another WTRU or available. For the remaining duration of the RLI up to the beginning of the GF resource, the WTRU may send a reservation signal, a reference signal, DM-RS, SRS, or the like.

[0135] FIG. 11 is an example of multiple GF PUSCH resources 1 100. In 1 100, a WTRU may randomly choose a listen interval up to RLI1 :RLI1 WTRU or RLI2: RLI2WTRU. FIG. 12 is an example of multiple GF PUSCH resources where each GF PUSCH may have a RLI with a different size 1200 and varying RLIWTRU 1202 from 2-4 symbols. A network device may make available multiple GF PUSCH across a wider bandwidth, BWP, or the like. A WTRU may monitor more than one GF

PUSCH resource(s) and perform a separate LBT for each, such as in parallel, simultaneously, concurrently, or the like. In 1200, a WTRU may perform energy detection on the listen interval of RLM WTRU, out of RLI 1 symbols and on the BW of the first GF resource, RLI2WTRU, out of RLI2 symbols and on the BW of the second GF resource, and RU3WTRU, out of RLI3 symbols and on the BW of the third GF resource. If detected energy or power on the shortest of the three listen intervals is less than the associated threshold, the WTRU may determine the GF PUSCFI resource(s) that is associated with the shortest listen interval is available and may use that GF PUSCFI resource(s) for transmissions. The WTRU may then forego the energy or signal detection on other parallel resources.

[0136] If the detected energy or power on the previously considered listen interval, such as the shortest of the three listen intervals, is larger than the threshold, the WTRU may forego, discontinue, or abandon monitoring that associated GF PUSCFI resource(s) and consider the resource(s) associated with the next shortest listen interval, such as the second shortest of the set of listen intervals. If the detected energy on the next shortest listen interval is less than the associated threshold then the WTRU may determine that the medium is not in use by any other WTRU for that resource(s) and may use that GF PUSCFI resource(s) for communication or transmissions. The WTRU may then abandon energy or signal detection on the other remaining parallel resources unless the WTRU is capable of more than one TB transmission during similar times, in which case the WTRU may keep performing energy detection evaluation for the remaining resources. If the detected energy on that listen interval is larger than the associated threshold or limit, then the WTRU may assume the resource(s) is busy, taken by another WTRU, unavailable, or the like and the WTRU may consider the next shortest listen interval.

[0137] If the detected energy on the shortest of the three listen intervals is less than the associated threshold, the WTRU may determine the GF PUSCFI resource(s) that is associated with the shortest listen interval is not in use by any other WTRU for that resource(s) or available and use that GF PUSCFI resource(s) for transmissions. The WTRU may then abandon energy or signal detection on the other remaining parallel resources.

[0138] In addition, if the detected energy on a considered listen interval, such as the shortest of the three listen intervals, is larger than the threshold, the WTRU may forego or abandon monitoring that associated GF PUSCFI resource(s) and consider the resource(s) associated with the next shortest listen interval, such as the second shortest of the set of listen intervals. If the detected energy on a listen interval is less than the associated threshold then the WTRU assumes the medium is not in use by any other WTRU for that resource(s) or available and may utilize that GF PUSCFI resource(s) for communication or transmissions. The WTRU may skip energy or signal detection on the other remaining parallel resources, unless the WTRU is capable of more than one TB transmission during a similar time. For this configuration, a WTRU may keep energy detection evaluation for the remaining resources. If the detected energy on that listen interval is larger than the associated threshold, the WTRU may determine the resource(s) is busy, occupied, unavailable, or the like and considers the next shortest listen interval.

[0139] FIG. 13 is an example procedure for transmitting in a set of GF resources 1300. A WTRU may obtain attributes and the associated RLI to access each GF resource (1302). A WTRU may prepare to transmit a TB in a set of upcoming GF resources on the same time across RBs and perform first step of LBT using a LBT category (1304). If the first stage or step of LBT is completed successfully (1306), a listen interval RLIWTRU may be pseudo-randomly chosen from {0, ...,RU} for each of the GF resources {RLU WTRU, RLI2WTRU, . . ., RU KWTRU} and, for each resource, EDGFBW calculated from the resource BW and EDBWP (1310). If unsuccessful, transmission may be abandoned for the GF resource (1308) and a WTRU may prepare again to transmit a TB in a set of upcoming GF resources on the same time across RBs and perform a first stage or step of LBT using a LBT category (1304).

[0140] In 1300, energy or sequence detection may be performed for all the listen intervals {RL11 WTRU, . . ., RLI KWTRU} in parallel (1312). If the detected energy on the remaining shortest listen intervals is less than the associated threshold (1314), the TB after the associated RLIWTRU may be transmitted or transmit a signal, DM-RS, reservation, or the like from RLIWTRU until RLI and transmit the TB after RLI (1318). If the detected energy is more than the associated threshold, the shortest listen interval may be dropped and a determination made for remaining listen intervals (1316). If a listen interval still remains, the next shortest listen interval is chosen (1320) and energy is again monitored for an associated threshold (1314). Otherwise, transmission may be abandoned for the GF resource(s) (1308).

[0141] In certain configurations, the first stage or step of LBT may be performed on a wider bandwidth, such as the BWP, and the second stage or step of LBT may be performed on the bandwidth of the GF resource(s) in parallel. For this configuration, a WTRU may calculate the received energy on the wider bandwidth, BWP, or the like for the duration of the LBT and up to the GF resource(s). If the detected energy during this interval exceeds the threshold EDBWP then the channel is determined to be busy, unavailable, occupied, or the like and the LBT procedure is failed. Otherwise, the WTRU may calculate the detected energy for the duration of the RLIWTRU within the RLI, and compares the detected energy with the adjusted threshold EDGFBW. If the detected energy is less that this threshold, then the GF resource(s) may be idle and available. For the remainder of the RLI in this configuration, the WTRU may send a reservation signal, RS, or the like before the start of data or TB transmission on the PUSCH resource(s).

[0142] FIG. 14 is a diagram of an NR slot that includes a RLI resource(s) sensing interval and a GF PUSCH resource(s) 1400. In 1400, a WTRU may be configured to select two values for a LBT interval based on CAT3 or draw a pseudo-random interval according to CAT4. For a resource sensing interval, RLIWTRU, a WTRU may start the LBT interval in such a way that the end of the interval coincides with RLIWTRU. In 1400, a LBT interval may comprise part of an NR slot. A RLI 1 sensing interval 1402 may comprise seven symbols. If energy detection during the LBT interval indicates a BWP may be idle and ready for use by the WTRU, then for the remaining duration of the RLI 1 1404 up to the beginning of the GF resource(s), the WTRU may send a reservation signal, a reference signal, DM-RS, SRS or the like.

[0143] FIG. 15 is a procedure for parallel operation of two sensing procedures 1500. A WTRU may obtain attributes and the associated RLI to access a GF resource(s) (1502). A TB may be prepared for transmission in an upcoming GF resource(s) (1504). A determination of the LBT procedure or interval may be performed, a listen interval, RLIWTRU, pseudo-randomly chosen from {0, ...,RLI}, and a EDGFBW calculated from the resource BW and EDBWP (1506). At each symbol the average detected energy may be determined (1 508). EDLBT may be the average detected energy during a LBT listen interval. EDRU may be the average detected energy during RLIWTRU. A determination is made if during the symbols when LBT is applicable, is EDi_BT>EDBWp or during the symbols when RLI is applicable, is EDRU>EDGFBW (1 510). If no and other conditions are met, then a TB after the associated RLIWTRU may be transmitted. In other configurations, if no and other conditions are met, a reservation, reference, RS, DM-RS, or the like signal from RLIWTRU until RLI and the TB after RLI may be transmitted (1514). Otherwise, transmission may be abandoned for the resource(s) (1512) and a TB may again be prepared for transmission in an upcoming GF resource(s) (1504).

[0144] A WTRU may perform alternative energy detection for the RLI. In certain configurations, energy detection may be based on the collected energy during the interval similar to a received signal strength indication (RSSI). A WTRU may also send a DM-RS during the duration after RLIWTRU up to the beginning or start of the GF resource(s). When a WTRU does send DM-RS during this interval, it could be during the RLIWTRU of another WTRU performing resource sensing.

[0145] When a network device or gNB configures WTRUs for MU-MIMO during the GF resource(s), there may be ambiguity of a DM-RS sequence out of the pool of sequences available for the WTRU. This scenario may occur since a network device or gNB may have configured multiple WTRUs to access one or more GF resources and utilize MU-MIMO techniques where large antenna arrays are configured on both sides. When many WTRUs are configured to a similar GF resource(s), a gNB or network device may not have configured WTRUs with a WTRU-specific DM- RS. In this configuration, a WTRU may select a sequence from the pool of DM-RS sequences pseudo-randomly or according to a pre-determined order. Flowever, due to possible selection of a similar sequence by more than one WTRU, a DM-RS collision is possible which leads to network incapability of detecting the individual WTRUs’ communication or transmission.

[0146] When a WTRU performs energy detection during its own resource sensing interval RLIWTRU, energy for a set of or all the DM-RS sequences known to the WTRU may be detected. During this operation, a WTRU may determine a likelihood that a DM-RS is in use by another WTRU. The WTRU may also be capable of determining one or more DM-RS sequences underutilized by other WTRUs and uses one or more of these DM-RS for the transmission during the rest of RLI, after the RLIWTRU_, and up to beginning of the resource(s). The WTRU may also utilize these underutilized or infrequently used DM-RS sequences during the GF resource(s).

[0147] In certain configurations, WTRUs may be configured with the maximum number of layers or users that can operate in MU-MIMO. When a WTRU determines the detected energy for a set of or all the DM-RS sequences and determines the likelihood that a DM-RS is in use by another WTRU, if the WTRU determines that the number of DM-RS sequences that are highly likely used by other WTRUs exceeds the maximum number of WTRUs or layers distinguishable within a MU- MIMO by the network, then the WTRU may determine that the resource(s) is not suitable. For this condition, selection of any DM-RS and transmission in that GF resource(s) may be abandoned. These conditions may be designated a failure of using the GF resource(s) similar to a LBT procedure failure.

[0148] In a configuration, non-orthogonal multiple access during a PUSCH resource(s) by multiple WTRUs may cause ambiguity of DM-RS usage. Ambiguity may exist, for example, if the network device or gNB has many WTRUs accessing one or more PUSCH resources capable of separable multiple transmissions by using non-orthogonal multiple access. Due to configuration of many WTRUs for a similar resource(s), a network device or gNB may not have configured WTRUs with WTRU-specific DM-RS. In this configuration, a WTRU may select a DM-RS from a pool of DM- RS pseudo-randomly, according to a pre-determined order, or the like. However, due to possible selection of a similar DM-RS by more than one WTRU, a DM-RS collision or conflict is possible, making detection of individual WTRUs’ communication or transmission at the network device difficult. [0149] A network device or gNB may schedule WTRUs with a RLI for each one or consecutive set of PUSCH resources for non-orthogonal multiple access. In this configuration, a WTRU may select a pseudo-random listen interval of RLIWTRU for the PUSCH resource(s) and perform DM-RS detection, such as match filtering, during the listen interval. When a WTRU performs energy detection or DM-RS match-filtering during a resource sensing interval RLIWTRU, the WTRU may rank the detected energy for a set of or all the DM-RS which is available to the WTRU. The WTRU may also determine a likelihood that a DM-RS sequence is or was used by another WTRU. The WTRU may also determine one or more DM-RS sequences where likely usage by other WTRUs is the least and use of one or more of these DM-RS sequences for the transmission during the remaining symbols of RLI and during the PUSCH resource(s). Once a WTRU identifies a DM-RS sequence to use, the WTRU may use the association of the DM-RS sequence to one or more other attribute of the non-orthogonal multiple-access and select the value or sequence of the attribute that is associated with the particular DM-RS sequence.

[0150] In non-orthogonal multiple-access, once a WTRU identifies the DM-RS sequence to use, the WTRU may select an associated signature sequence for subsequent communication or transmission. Also in non-orthogonal multiple-access, once a WTRU identifies the DM-RS sequence to use, the WTRU may select an associated transmission power value, or an array of power values, for subsequent transmission. In another configuration, once a WTRU identifies the DM-RS sequence to use, the WTRU may select an associated redundancy version value(s), coding rate(s), HARQ ID, or the like for subsequent transmission.

[0151] In certain configurations, one or more WTRUs may be configured with the maximum number of WTRUs that can operate within a resource(s) configured for a given non-orthogonal multiple access system. When the WTRU ranks the detected energy for a set of or all the DM-RS sequences, if the WTRU determines that the number of DM-RS sequences that are likely been used by other WTRUs exceeds the maximum number of WTRUs or layers distinguishable within the specific non-orthogonal multiple access within a PUSCH resource(s), the WTRU may assume that the resource(s) is not suitable for communication or transmission. As a result, selection of a DM-RS and transmission in a corresponding resource(s) may be forgone.

[0152] To resolve contention or conflict and select a value/sequence for one or more transmission attributes out of a set of the values/sequences for the one or more attributes, a WTRU may utilize a RLI at a beginning portion of the uplink resource(s) or it may be a separate resource(s) that is scheduled to be before an uplink resource(s). The separate resource(s) may still be within the same bandwidth as the uplink resource(s). The RLI may have a duration RLI and the WTRUs may be configured with possibly varying duration of RLI for each uplink resource(s).

[0153] The WTRU may select a listen interval with a pseudo-random duration, denoted as RLIWTRU, out of the maximum duration for the related resource(s). During RLIWTRU, the WTRU may perform a function such as energy detection, sequence detection, match filtering, or the like. The WTRU may perform energy detection during the RLIWTRU, such as measuring RSSI. The WTRU may perform sequence detection during the RLIWTRU, such as by measuring RSRP, RSRQ, or the like. The WTRU may perform a bank of match filtering for a set of sequences during the RLIWTRU, such as by detection of a set of DM-RS, SRS, CSI-RS, or the like. The WTRU may also perform a bank of match filtering for a set of sequences that are outside of a preferred set of RS or DM-RS sequences that the WTRU is configured with during the RLIWTRU such as by detection of a set of reference signals, DM-RS, SRS, CSI-RS, or the like.

[0154] The WTRU may perform likelihood estimation for a set of sequences during the RLIWTRU, such as for non-orthogonal multiple access. After energy or sequence detection, such as by RSSI, RSRP, RSRQ, or the like measurements, during the RLIWTRU, the WTRU may determine if there is any transmission within the RLI, indicating whether there is going to be any transmission within the uplink resource(s) that follows the RLI, or the like.

[0155] After energy, power, or sequence detection or threshold comparison for a set of sequences outside of a preferred set of sequences that the WTRU is configured with during the RLIWTRU, the WTRU may determine any transmissions within the RLI, indicating whether there is going to be any transmission, from the WTRUs disassociated with the preferred set of sequences of the WTRU within the uplink resource(s) that follows the RLI, or the like. Also, after sequence detection during the RLIWTRU, the WTRU may conclude sequence usage during the RLIWTRU and select one or more RS(s), DM-RS(s), SRS(s), or the like that are least likely in use within the RLI duration.

[0156] In certain configurations, the WTRU may decide not to select any sequence if the number of sequences that are likely in use during the RLIWTRU exceed a pre-configured threshold. For instance, in a MU-MIMO configuration, where a network device configured the WTRUs with the maximum number of WTRUs or layers that the network device can distinguish within a MU-MIMO transmission, a WTRU may avoid selecting a sequence and avoid participating in the MU-MIMO transmission in the resource(s) that follows the RLI. [0157] After likelihood estimation, such as of a signature or a function of a signature during the RLIWTRU, the WTRU may conclude which sequence or signature is likely in use and to select one or more signatures that have least likelihood of usage within the RLI duration. Additionally, the WTRU may decide not to select a signature if the number of signatures that are likely in use during the RLIWTRU exceed a pre-configured threshold. In non-orthogonal multiple access configurations, a network configured the WTRUs with the maximum number of WTRUs or layers that the network can distinguish signals within the non-orthogonal multiple access, a WTRU may avoid selecting a signature and avoid participating in the non-orthogonal multiple access transmission in the resource(s) that follows the RLI.

[0158] Additionally, the WTRU may select a value or sequence based on one or more other transmission attributes given herein. In a configuration, in association with the selection of a RS, DM-RS, SRS, or the like, other attributes may include to select a sequence for non-orthogonal multiple access signature, select a transmit power value(s), select a redundancy version (RV), select a HARQ ID, or the like.

[0159] In certain configurations, a multi-level LBT may be performed. This configuration may include efficient co-existence for an NR-U WTRU with various categories of competitors. Efficient co-existence may include collaborating among NR-U network devices, gNBs, WTRUs, or the like.

[0160] An NR-U WTRU or gNB that attempts to perform LBT may do so by performing several energy detection operations in parallel. Energy detection may be performed across the operation bandwidth and include a determination whether the detected energy level is above a specified or predetermined threshold. A network device or gNB may simultaneously perform energy detection across several BWPs and begin transmission on one or more BWPs if the LBT is completed successfully on each BWP. If a WTRU is capable of operating in multiple BWPs, the WTRU may check simultaneously for the presence of a network-initiated COT in the multiple BWPs where the WTRU may perform detection per a priority list among the BWPs. If the WTRU detects the presence of a COT in one of the BWPs, it may continue reception on the COT within that BWP. If the WTRU detects the presence of a COT in more than one of the BWPs, it may continue reception on the COT that has the highest priority.

[0161] An NR-U WTRU, gNB, or network device may detect the presence of LAA, 802.1 1x, LTE, NR-U, or other RATs by performing custom operations, such as cyclic-prefix detection. After detection of a specific RAT or numerology of NR-U, the NR-U device may compare the detected energy level with various pre-configured thresholds where the co-existence with the detected RAT or numerology may be adaptive. To adapt the co-existence with the detected RAT or numerology, an NR-U WTRU, gNB, or network device may attempt to detect the presence of a cyclic-prefix by performing auto-correlation of the received signal with a delayed version of the same signal. The amount of the delay may be obtained from the numerology and the length of the cyclic prefix. For example, if the OFDM symbol duration is TOFDM and the duration of the cyclic-prefix is TCP, then the delay may be TOFDM+TCP.

[0162] In a configuration, an NR-U device may select to monitor multiple numerologies or multiple cyclic-prefix lengths for a given terminology and detect energy that may be compared to a scaled version of EDBWP. An NR-U device may also select to monitor other RATs that also use OFDM or OFDMA technology. For example, an NR-U device may monitor for presence of 802.1 1 technologies by performing multiple cyclic-prefix detectors where each is targeted for one of the 802.11 numerologies. An NR-U device may increase tolerance with a specific NR numerology by decreasing a threshold for which only a detected energy below that threshold indicates an idle channel. Such configuration of an NR-U network device by the network or configuration of an NR-U WTRU by a gNB may be based on deployment of multiple NR-U cells by the same operator. This may be desirable for an operator that seeks improved co-existence among NR-U cells, particularly at the cell edges.

[0163] An NR-U device may increase tolerance with a specific RAT by decreasing the threshold for idle or available channel detection. Such configuration of an NR-U network device by the network or configuration of an NR-U WTRU by a gNB may be based on deployment of the other RAT by the same operator. This may be desirable for an operator seeking better co-existence among multiple- deployed technologies, such as NR-U, 802.1 1x, LTE unlicensed, or the like technologies in similar geographical areas.

[0164] An NR-U device may decide, or be configured, to deprioritize co-existence and decrease a tolerance level with a specific NR numerology or to a RAT not recognized as part of a preferred set of RATs if associated with a different operator. This may be achieved by increasing the energy detect threshold. For example, if the energy detect threshold for a 20 MFIz bandwidth is -72 dBm, for a RAT or numerology that is not part of a set of preferred RATs, the threshold might be increased to -77 dBm or -62 dBm. In another example, a WTRU that transmits a short channel, such as a sPUCCFI, FIARQ-ACK feedback, SR, or the like, may use an increased energy detect threshold, and, for remaining transmissions, may use a more tolerant threshold or default threshold. In certain configurations, the COT established by a RAT or numerology that is outside a set of preferred RATs may be ignored or disregarded. [0165] Prioritization of co-existence between a set of network devices or gNBs may including forming a set of prioritized or preferred devices that operate within the same channel or share at least one BWP. This may be achieved by detecting a broadcast channel(s), SSB, OSI, SIBs, or the like of all the network devices nearby and obtaining information indicating that the network devices belongs to the same entity as the receiving or detecting network device. Along with this information, the network device may obtain a network device group identification, such as a gNBgroup-RNTI, to scramble a particular downlink channel. For example, a gNB that belongs to a set of prioritized or preferred gNBs may send a particular downlink control channel or PDCCH that is scrambled with a particular RNTI detectable by the gNBs. The search space for this PDCCH may be a priori known by the gNBs. The search space may be configured by a higher layer configuration, RRC message, RRC signaling, transmission via any of the broadcast channels, or the like. The content of such PDCCH may vary and may include, for example, the duration of the COT.

[0166] In certain configurations, as long as the receiving gNB or the receiving WTRU detects a PDCCH using the gNB group identification, gNBgroup-RNTI, or the like, it may infer that the channel is being used by a member of a preferred or prioritized set of gNBs. In this configuration, the receiving gNB may apply a more tolerant energy detection threshold or may apply other more tolerant co-existence operations. If a receiving gNB or the receiving WTRU cannot detect a PDCCH using a gNB group identification, the gNB may infer that the channel is being used by a gNB that is not a member of the preferred or prioritized set of gNBs. In this configuration, the receiving gNB may apply less tolerant energy detection thresholds or may apply other less tolerant co-existence operation.

[0167] In certain configurations, a gNB may be part of one or more sets of preferred or prioritized sets of gNBs, where for each set there may be a group-identification that is a priori known by the gNB group, and may apply varying levels of co-existence operations for each set. For example, a gNB may associate a more tolerant energy detection threshold for one set and associate a different energy detection threshold for another set of gNBs.

[0168] Although features and elements are described above in particular combinations, one of ordinary skill in the art will appreciate that each feature or element can be used alone or in any combination with the other features and elements. In addition, the methods described herein may be implemented in a computer program, software, or firmware incorporated in a computer-readable medium for execution by a computer or processor. Examples of computer-readable media include electronic signals (transmitted over wired or wireless connections) and computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, a read only memory (ROM), a random access memory (RAM), a register, cache memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magneto-optical media, and optical media such as CD-ROM disks, and digital versatile disks (DVDs). A processor in association with software may be used to implement a radio frequency transceiver for use in a

WTRU, UE, terminal, base station, RNC, or any host computer.

Claims

CLAIMS What is Claimed:

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

a transceiver configured to receive, from a network device, a reference signal (RS) during a first time interval;

a processor configured to perform, during the first time interval, a first listen-before-talk

(LBT);

the processor configured, on a condition that the first LBT is successful, to perform a second LBT during a second time interval having resource listen interval (RLI) symbols and grant free (GF) physical uplink shared channel (PUSCH) resources, wherein the second LBT is based on a selected random number of the RLI symbols;

the transceiver configured to transmit, on a condition that measured energy of first RSs during the selected random number of the RLI symbols is less than a threshold, one or more second RSs up to a remaining number of the RLI symbols; and

the transceiver further configured to transmit, after the RLI symbols, a transport block on the GF PUSCH resources.

2. The WTRU of claim 1 , wherein the RS during the first time interval is for a whole bandwidth or bandwidth part (BWP) and prevents usage of resources by other WTRUs.

3. The WTRU of claim 1 , wherein the first time interval and the second time interval is part of a channel occupancy time (COT).

4. The WTRU of claim 1 , wherein the RLI symbols and the GF PUSCH resources are configured by higher layer signalling received from the network device.

5. The WTRU of claim 1 , wherein the selected random number of the RLI symbols is based on a LBT category.

6. The WTRU of claim 1 , wherein the RS, the first RSs, or the second RSs are demodulation reference signals (DM-RS).

7. The WTRU of claim 1 further comprising the processor configured, on a condition that the first LBT is successful, to perform a different LBT on each of multiple configured GF PUSCH resources.

8. A method performed by a wireless transmit/receive unit (WTRU), the method comprising:

receiving, by the WTRU from a network device, a reference signal (RS) during a first time interval; performing, by the WTRU during the first time interval, a first listen-before-talk (LBT);

performing, by the WTRU on a condition that the first LBT is successful, a second LBT during a second time interval having resource listen interval (RLI) symbols and grant free (GF) physical uplink shared channel (PUSCH) resources, wherein the second LBT is based on a selected random number of the RLI symbols;

transmitting, by the WTRU on a condition that measured energy of first RSs during the selected random number of the RLI symbols is less than a threshold, one or more second RSs up to a remaining number of the RLI symbols; and

transmitting, by the WTRU after the RLI symbols, a transport block on the GF PUSCH resources.

9. The method of claim 8, wherein the RS during the first time interval is for a whole bandwidth or bandwidth part (BWP) and prevents usage of resources by other WTRUs.

10. The method of claim 8, wherein the first time interval and the second time interval is part of a channel occupancy time (COT).

1 1. The method of claim 8, wherein the RLI symbols and the GF PUSCH resources are configured by higher layer signalling received from the network device.

12. The method of claim 8, wherein the selected random number of the RLI symbols is based on a LBT category.

13. The method of claim 8, wherein the RS, the first RSs, or the second RSs are demodulation reference signals (DM-RS).

14. The method of claim 8 further comprising performing, on a condition that the first LBT is successful, a different LBT on each of multiple configured GF PUSCH resources.