Methods and apparatus for pusch repetition

Abstract

To provide methods and apparatus for performing a channel access procedure and transmitting a set of repetitions.SOLUTION: A wireless transmit / receive unit (WTRU) may be configured to receive information to transmit uplink data. The information may indicate a first number of nominal repetitions and a first number of symbols for each of the first number of nominal repetitions. The WTRU may be configured to determine a set of symbols associated with a first nominal repetition and to transmit a second number of actual repetitions in symbols associated with the first nominal repetition. The second number of actual repetitions and the symbols used to transmit the second number of actual repetitions may be based on an occurrence of an event during the set of symbols associated with the first nominal repetition. The set of symbols associated with the first nominal repetition may comprise one or more subsets of consecutive uplink symbols.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] (Cross - Reference to Related Applications) This application claims the benefit of U.S. Provisional Patent Application No. 63 / 167,953, filed Mar. 30, 2021, and U.S. Provisional Patent Application No. 63 / 185,576, filed May 7, 2021, the contents of which are incorporated herein by reference.

Background Art

[0002] Different types of Physical Uplink Shared Channel (PUSCH) repetitions are defined. Repetition type A allows for a single repetition per slot. The extended repetition type A for 5G New Radio for unlicensed spectrum (NR - U) allows for multiple repetitions per slot but with a fixed mapping across all slots. Repetition type B allows for sub - slot repetitions by using nominal repetitions. Multi - TTI scheduling has advantages such as reducing the amount of scheduling signaling. Further, multi - TTI scheduling can reduce the need for Listen - Before - Talk (LBT) before all transmissions when all PUSCHs are mapped to full slots. There is a need for methods and apparatuses that enable sub - slot repetitions in an unlicensed environment and enable multi - TTI scheduling with repetitions.

Summary of the Invention

[0003] A Wireless Transmit / Receive Unit (WTRU) can be configured to receive information for transmitting uplink data. The uplink data can be transmitted via a PUSCH. The information can indicate a first number of nominal repetitions and a first number of symbols for each of the first number of nominal repetitions. The WTRU can be configured to determine a set of symbols associated with a first nominal repetition. The WTRU can be configured to transmit a second number of actual repetitions in the symbols associated with the first nominal repetition. The second number of actual repetitions and the symbols used to transmit the second number of actual repetitions can be based on the occurrence of an event in the set of symbols associated with the first nominal repetition. The event can be at least one of an end of a Channel Occupancy Time (COT), a channel access resource, a channel access procedure result, a start time of an idle period of a Fixed Frame Period (FFP), or an end time of an idle period of an FFP. The set of symbols associated with the first nominal repetition can comprise one or more subsets of consecutive uplink symbols. At least one of the one or more subsets of consecutive uplink symbols can comprise at least two symbols. One subset of the one or more subsets of consecutive uplink symbols can be non-overlapping with another subset of the one or more subsets of consecutive uplink symbols. On the condition that an event occurs in the set of symbols associated with the first nominal repetition, the WTRU can be configured to transmit a first actual repetition in one or more uplink symbols of one or more subsets of consecutive uplink symbols before the occurrence of the event, and on the condition that the channel access procedure is successful, to transmit a second actual repetition in one or more uplink symbols of one or more subsets of consecutive uplink symbols after the occurrence of the event after transmitting the first actual repetition.The first actual repetition may not be transmitted in the symbol after the event. The channel access procedure may be a listen before talk (LBT) procedure. The channel access procedure may be based on at least one of channel occupancy time (COT) timing, COT initiator, fixed frame period (FFP) timing, previous channel access procedure result, whether a gap precedes the repetition, the size of the gap between repetitions, or the cause of the gap between repetitions. The actual repetition of the second number of actual repetitions may comprise at least one of configured grant uplink control information (CG-UCI), demodulation reference signal (DM-RS), scheduling request (SR), channel state information (CSI), hybrid automatic repeat request (HARQ) acknowledgement (ACK), or transport block (TB). The WTRU may be configured to receive configuration information regarding resources for performing the channel access procedure. The resources may comprise at least one of a set of time instances, a set of frequency regions, or a beam.

[0004] The WTRU may be configured to determine when to execute channel access procedures. The determination of when to execute channel access procedures may be based on at least one of the number of repetitions, the size of the gap between repetitions, the cause of the gap between repetitions, frequency hopping, beam change, channel occupancy time (COT) timing, whether the COT is user-initiated or network-initiated, fixed frame period (FFP) timing, or the result of a previous channel access procedure. The WTRU may be configured to receive an indication of a set of invalid resources. The set of invalid resources may not be used to transmit a set of repetitions. The indication may include information regarding the type of channel access to use to resume transmission. The WTRU may be configured to receive a semi-static configuration of the type of channel access to use to resume transmission. The indication of the set of invalid resources may be received in downlink control information (DCI). The WTRU may be configured to receive configuration information regarding resources for performing LBT. The resources may include at least one of a set of time instances, a set of frequency regions, or a beam. The repetitions may be associated with a set of possible start times. The WTRU may be configured to determine that the channel is idle and transmit the repetitions at a first start time. The WTRU may be configured to determine that the channel is busy and perform a second LBT procedure before a second start time. The WTRU may be configured to send an indication of which LBT procedure was successful for the repeated transmission. The WTRU may be configured to receive configuration information indicating a set of nominal repetitions, determine a set of symbols in which the nominal repetitions may occur, and determine whether the set of symbols in which the nominal repetitions may occur is valid. The determination of whether the set of symbols in which the nominal repetitions may occur is valid may be based on at least one of whether LBT is required before the repetitions, COT boundary timing, FFP idle period timing, or the result of a previous LBT.The WTRU may be configured to segment a nominal repetition if the nominal repetition contains one or more invalid symbols within the nominal repetition. The WTRU may be configured to determine the LBT type to use before the repetition. The determination of the LBT type to use may be based on at least one of COT timing, COT indicator, COT status, gap size, cause of the gap, or whether the transmission is for a TB different from the previous repeated transmission that precedes it. The repeated transmission may include at least one of CG-UCI, DM-RS, UCI, or TB. The WTRU may be configured to skip, cancel, or postpone the repetition if an LBT failure occurs. The WTRU may be configured to receive configuration information indicating the resources for transmitting a plurality of transport blocks. The WTRU may be configured to transmit all repetitions of a TB before transmitting a repetition of another TB. The WTRU may be configured to transmit all first repetitions of all TBs before transmitting a second repetition of a TB. The WTRU may be configured to receive configuration information regarding an LBT bandwidth frequency hopping pattern information. The WTRU may be configured to perform frequency hopping between repeated transmissions.

Brief Description of the Drawings

[0005] A more detailed understanding can be obtained from the following description given by way of example in conjunction with the accompanying drawings, in which like reference numerals in the figures indicate like elements.

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[0006] FIG. 1A is a diagram showing an exemplary communication system 100 in which one or more of the disclosed embodiments can be implemented. The communication system 100 can be a multi-access system that provides content such as voice, data, video, messaging, broadcast, etc. to a plurality of wireless users. The communication system 100 can enable a plurality of wireless users to access the above-described content through sharing of system resources including wireless bandwidth. For example, the communication system 100 can use 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 filter type OFDM, filter bank multicarrier (FBMC).

[0007] As shown in Figure 1A, the communication system 100 can include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, a radio access network (RAN) 104, a core network (CN) 106, a public switched telephone network (PSTN) 108, the Internet 110, and other networks 112, although it will be understood that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network elements. Each of the WTRUs 102a, 102b, 102c, 102d can 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, which may all be referred to as stations (STAs), can be configured to transmit and / or receive wireless signals and can include user equipment (UE), mobile stations, fixed or mobile subscriber units, subscriber-based units, pocket bells, cellular telephones, personal digital assistants (PDAs), smartphones, laptops, netbooks, personal computers, wireless sensors, hotspots or Mi-Fi devices, Internet of Things (IoT) devices, watches or other wearables, head-mounted displays (HMDs), vehicles, drones, medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in an industrial and / or automated processing chain context), consumer electronics devices, devices operating in commercial and / or industrial wireless networks, etc. Any of the WTRUs 102a, 102b, 102c, and 102d can also be referred to interchangeably as a UE.

[0008] The communication system 100 may also include base station 114a and / or base station 114b. Each of base stations 114a, 114b may be any type of device configured to wirelessly interface with at least one of WTRUs 102a, 102b, 102c, 102d to facilitate access to one or more communication networks such as CN 106, the Internet 110, and / or other network 112. By way of example, base stations 114a, 114b may be a base transceiver station (BTS), NodeB, eNode B (eNB), Home Node B, Home eNode B, next generation NodeB such as gNode B (gNB), new radio (NR) NodeB, site controller, access point (AP), wireless router, and the like. Although base stations 114a, 114b are each shown as a single element, it will be understood that base stations 114a, 114b may include any number of interconnected base stations and / or network elements.

[0009] Base station 114a can be part of RAN104, which can also include other base stations such as a base station controller (BSC), a radio network controller (RNC), a relay node, and / or network elements (not shown). Base station 114a and / or base station 114b can be configured to transmit and / or receive radio signals on one or more carrier frequencies that can be referred to as a cell (not shown). These frequencies can be in the licensed spectrum, the unlicensed spectrum, or a combination of the licensed and unlicensed spectra. A cell can provide wireless service coverage to a specific geographic area that can be relatively fixed or can change over time. A cell can be further divided into cell sectors. For example, the cell associated with base station 114a can be divided into three sectors. Thus, in one embodiment, base station 114a can include three transceivers, i.e., one transceiver per sector of the cell. In one embodiment, base station 114a can use multiple-input multiple-output (MIMO) technology and can utilize multiple transceivers per sector of the cell. For example, beamforming can be used to transmit and / or receive signals in a desired spatial direction.

[0010] Base stations 114a, 114b can communicate with one or more of WTRUs 102a, 102b, 102c, 102d via air interface 116, which can be any suitable wireless communication link (e.g., radio frequency (RF), microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet (UV), visible light, etc.). Air interface 116 can be established using any suitable radio access technology (RAT).

[0011] More specifically, as described above, the communication system 100 can be a multiple access system and can use one or more channel access schemes such as, for example, CDMA, TDMA, FDMA, OFDMA, SC-FDMA, etc. For example, the base station 114a of RAN104 and WTRU102a, 102b, 102c can establish the air interface 116 using wideband CDMA (WCDMA), and can implement radio technologies such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA). WCDMA can include communication protocols such as High-Speed Packet Access (HSPA) and / or Evolved HSPA (HSPA+). HSPA can include High-Speed Downlink Packet Access (HSDPA) and / or High-Speed Uplink Packet Access (HSUPA).

[0012] In one embodiment, the base station 114a and WTRU102a, 102b, 102c can implement radio technologies such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which can establish the air interface 116 using Long Term Evolution (LTE) and / or LTE-Advanced (LTE-A) and / or LTE-Advanced Pro (LTE-A Pro).

[0013] In one embodiment, the base station 114a and WTRU102a, 102b, 102c can implement radio technologies such as NR radio access, which can establish the air interface 116 using NR.

[0014] In one embodiment, base station 114a and WTRUs 102a, 102b, 102c may implement multiple radio access technologies. For example, base station 114a and WTRUs 102a, 102b, 102c may implement LTE radio access and NR radio access together, for example, using the dual connectivity (DC) principle. Accordingly, the air interface utilized by WTRUs 102a, 102b, 102c may be characterized by multiple types of radio access technologies transmitted to / from multiple types of base stations (e.g., eNBs and gNBs) and / or transmissions.

[0015] In other embodiments, base station 114a and WTRUs 102a, 102b, 102c may implement wireless technologies such as IEEE 802.11 (i.e., Wireless Fidelity (WiFi)), IEEE 802.16 (i.e., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile communications (GSM), Enhanced Data rates for GSM Evolution (EDGE), GSM EDGE (GERAN), etc.

[0016] The base station 114b in FIG. 1A can be, for example, a wireless router, a Home Node B, a Home eNode B, or an access point, and can utilize any suitable RAT to facilitate wireless connections in a local area such as an office, a home, a vehicle, a campus, an industrial facility, an aerial corridor (for example, for use by a drone), a location such as a road, etc. In one embodiment, the base station 114b and the WTRUs 102c, 102d can implement a wireless technology such as IEEE 802.11 to establish a wireless local area network (WLAN). In one embodiment, the base station 114b and the WTRUs 102c, 102d can implement a wireless technology such as IEEE 802.15 to establish a wireless personal area network (WPAN). In yet another embodiment, the base station 114b and the WTRUs 102c, 102d can utilize a cellular-based RAT (for example, WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.) to establish a pico cell or a femto cell. As shown in FIG. 1A, the base station 114b can have a direct connection to the Internet 110. Thus, the base station 114b may not need to access the Internet 110 via the CN 106 in some cases.

[0017] RAN104 can communicate with CN106, which can be any type of network configured to provide voice, data, applications, and / or voice over internet protocol (VoIP) services to one or more of WTRU102a, 102b, 102c, 102d. The data can have various quality of service (QoS) requirements, such as different throughput requirements, latency requirements, error tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, etc. CN106 can provide call control, billing services, mobile location-based services, prepaid calls, internet connectivity, video delivery, etc., and / or perform high-level security functions such as user authentication. Although not shown in Figure 1A, it will be understood that RAN104 and / or CN106 can communicate directly or indirectly with other RANs using the same or a different radio access technology (RAT) as RAN104. For example, in addition to being connected to RAN104 that can utilize New Radio (NR) radio technology, CN106 can also communicate with another RAN (not shown) using GSM, UMTS, CDMA2000, WiMAX, E-UTRA, or WiFi radio technology.

[0018] CN106 may also function as a gateway for WTRU102a, 102b, 102c, 102d to access the PSTN108, the Internet 110, and / or other networks 112. The PSTN 108 may include a public switched telephone network that provides plain old telephone service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices, where these networks and devices use common communication protocols such as the transmission control protocol (TCP), the user datagram protocol (UDP), and / or the internet protocol (IP) of the TCP / IP internet protocol suite. The network 112 may include wired and / or wireless communication networks owned and / or operated by other service providers. For example, the network 112 may include another CN connected to one or more RANs that may use the same RAT as the RAN 104 or a different RAT.

[0019] Some or all of the WTRU102a, 102b, 102c, 102d in the communication system 100 may include multimode capabilities (e.g., the WTRU102a, 102b, 102c, 102d may include multiple transceivers for communicating with different wireless networks via different wireless links). For example, the WTRU102c shown in Figure 1A may be configured to communicate with a base station 114a that may use cellular-based wireless technology and a base station 114b that may use IEEE802 wireless technology.

[0020] Figure 1B is a system diagram showing an exemplary WTRU 102. As shown in Figure 1B, the WTRU 102 may include, among other things, a processor 118, a transceiver 120, a transmit / receive element 122, a speaker / microphone 124, a keypad 126, a display / touchpad 128, a non-removable memory 130, a removable memory 132, a power supply 134, a global positioning system (GPS) chipset 136, and / or other peripheral devices 138. It will be understood that the WTRU 102 may include any partial combination of the foregoing elements while remaining consistent with one embodiment.

[0021] The processor 118 may be a general-purpose processor, a dedicated processor, a conventional processor, a digital signal processor (DSP), multiple microprocessors, one or more microprocessors associated with a DSP core, a controller, a microcontroller, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), any other type of integrated circuit (IC), a state machine, etc. The processor 118 may perform signal coding, data processing, power control, input / output processing, and / or any other functionality that enables the WTRU 102 to operate in a wireless environment. The processor 118 may be coupled to a transceiver 120 that may be coupled to a transmit / receive element 122. Although Figure 1B shows the processor 118 and the transceiver 120 as separate components, it will be understood that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip.

[0022] The transmit / receive element 122 may be configured to transmit signals to a base station (e.g., base station 114a) via the air interface 116 or receive signals from the base station (e.g., base station 114a). For example, in one embodiment, the transmit / receive element 122 may be an antenna configured to transmit and / or receive RF signals. In one embodiment, the transmit / receive element 122 may be an emitter / detector configured to transmit and / or receive, for example, IR, UV, or visible light signals. In yet another embodiment, the transmit / receive element 122 may be configured to transmit and / or receive both RF signals and optical signals. It will be understood that the transmit / receive element 122 may be configured to transmit and / or receive any combination of wireless signals.

[0023] The transmit / receive element 122 is shown in FIG. 1B as a single element, but 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 via the air interface 116.

[0024] The transceiver 120 may be configured to modulate signals transmitted by the transmit / receive element 122 and demodulate signals received by the transmit / receive element 122. As noted above, the WTRU 102 may have multi-mode capabilities. Thus, the transceiver 120 may include multiple transceivers to enable the WTRU 102 to communicate via multiple RATs such as, for example, NR and IEEE 802.11.

[0025] The processor 118 of the WTRU 102 may be coupled to the speaker / microphone 124, keypad 126, and / or display / touchpad 128 (e.g., a liquid crystal display (LCD) display unit or an organic light-emitting diode (OLED) display unit) and may receive data input by the user from these. The processor 118 may also output user data to the speaker / microphone 124, keypad 126, and / or display / touchpad 128. In addition, the processor 118 may access information from and store data in any type of suitable memory, such as the non-removable memory 130 and / or the removable memory 132. The non-removable memory 130 may include random-access memory (RAM), read-only memory (ROM), a hard disk, or any other type of memory storage device. The removable memory 132 may include a subscriber identity module (SIM) card, a memory stick, a secure digital (SD) memory card, etc. In other embodiments, the processor 118 may access information from and store data in a memory that is not physically located on the WTRU 102, such as on a server or a home computer (not shown).

[0026] Processor 118 can receive power from power source 134 and can be configured to distribute and / or control power to other components in WTRU 102. Power source 134 can be any suitable device for supplying power to WTRU 102. For example, power source 134 can include one or more dry batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, and the like.

[0027] Processor 118 can also be coupled to GPS chipset 136, which can be configured to provide location information (e.g., longitude and latitude) regarding the current location of WTRU 102. In addition to or instead of information from GPS chipset 136, WTRU 102 can receive location information from a base station (e.g., base stations 114a, 114b) via air interface 116 and / or can determine its location based on the timing of signals received from two or more nearby base stations. It will be understood that WTRU 102 can obtain location information by any suitable positioning method while remaining consistent with one embodiment.

[0028] The processor 118 may be further coupled to other peripheral devices 138, which may include one or more software and / or hardware modules that provide additional features, functionality, and / or wired or wireless connections. For example, the peripheral devices 138 may include an accelerometer, an electronic compass, a satellite transceiver, a digital camera (for photos and / or videos), a universal serial bus (USB) port, a vibration device, a television transceiver, a hands-free headset, 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 / Augmented Reality (VR / AR) device, an activity tracker, etc. The peripheral devices 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, etc.

[0029] The WTRU 102 may include a full-duplex radio in which some or all of the transmission and reception of signals (e.g., associated with specific subframes for both UL (e.g., for transmission) and DL (e.g., for reception)) may be simultaneous and / or together. The full-duplex radio may include an interference management unit for reducing and / or substantially eliminating self-interference either through hardware (e.g., a choke) or signal processing via a processor (e.g., via a separate processor (not shown) or the processor 118). In one embodiment, the WTRU 102 may include a half-duplex radio for some or all of the transmission and reception of signals (e.g., associated with a specific subframe for either UL (e.g., for transmission) or DL (e.g., for reception)).

[0030] Figure 1C is a system diagram illustrating RAN 104 and CN 106 according to one embodiment. As described above, RAN 104 can communicate with WTRUs 102a, 102b, 102c via air interface 116 using E-UTRA radio technology. RAN 104 can also communicate with CN 106.

[0031] RAN 104 can include eNode-Bs 160a, 160b, 160c, although it will be understood that RAN 104 can include any number of eNode-Bs while remaining consistent with one embodiment. Each of eNode-Bs 160a, 160b, 160c can include one or more transceivers for communicating with WTRUs 102a, 102b, 102c via air interface 116. In one embodiment, eNode-Bs 160a, 160b, 160c can implement MIMO technology. Thus, eNode-B 160a, for example, can transmit wireless signals to and / or receive wireless signals from WTRU 102a using multiple antennas.

[0032] Each of eNode-Bs 160a, 160b, 160c can be associated with a particular cell (not shown) and can be configured to handle radio resource management decisions, handover decisions, user scheduling, etc. in UL and / or DL. As shown in Figure 1C, eNode-Bs 160a, 160b, 160c can communicate with each other via the X2 interface.

[0033] CN 106 shown in Figure 1C can include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (PGW) 166. Although the foregoing elements are shown as part of CN 106, it will be understood that any of these elements can be owned and / or operated by an entity other than the CN operator.

[0034] The MME 162 can be connected to each of the eNode-Bs 162a, 162b, and 162c in the RAN 104 via the S1 interface and can function as a control node. For example, the MME 162 can authenticate users of the WTRUs 102a, 102b, 102c, activate / deactivate bearers, select a gateway for a particular service during the initial attach of the WTRUs 102a, 102b, 102c, etc. The MME 162 can provide control plane functions for switching between the RAN 104 and other RANs (not shown) that employ other radio technologies such as GSM and / or WCDMA.

[0035] The SGW 164 can be connected to each of the eNode-Bs 160a, 160b, and 160c in the RAN 104 via the S1 interface. The SGW 164 can generally route and transfer user data packets to / from the WTRUs 102a, 102b, 102c. The SGW 164 can perform other functions such as anchoring the user plane during an eNode B handover, triggering paging when DL data is available to the WTRUs 102a, 102b, 102c, and managing and storing the context of the WTRUs 102a, 102b, 102c.

[0036] The SGW 164 can be connected to the PGW 166, and the PGW 166 can provide the WTRUs 102a, 102b, 102c with access to a packet switched network such as the Internet 110 to facilitate communication between the WTRUs 102a, 102b, 102c and IP-enabled devices.

[0037] CN106 may facilitate communication with other networks. For example, CN106 may provide access to a circuit-switched network such as the PSTN108 to the WTRU102a, 102b, 102c to facilitate communication between the WTRU102a, 102b, 102c and a conventional landline communication device. For example, CN106 may include or communicate with an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that functions as an interface between CN106 and the PSTN108. In addition, CN106 may provide the WTRU102a, 102b, 102c with access to another network 112, which may include other wired and / or wireless networks owned and / or operated by other service providers.

[0038] The WTRU is described as a wireless terminal in FIGS. 1A - 1D, but in certain representative embodiments, it is contemplated that such a terminal may use a (e.g., temporarily or permanently) wired communication interface with a communication network.

[0039] In a representative embodiment, the other network 112 may be a WLAN.

[0040] An infrastructure basic service set (BSS) mode WLAN may have an access point (AP) of the BSS and one or more stations (STAs) associated with the AP. The AP may have access or an interface to a distribution system (DS) that carries traffic within and / or outside the BSS or to another type of wired / wireless network. Traffic originating from outside the BSS and destined for the STA can reach and be delivered to the STA through the AP. Traffic originating from the STA and destined for a destination outside the BSS can be sent to the AP and then sent to their respective destinations. Traffic between STAs within the BSS can be sent, for example, through the AP. The source STA can send the traffic to the AP, and the AP can deliver the traffic to the destination STA. Traffic between STAs within the BSS can be regarded as and / or referred to as peer-to-peer traffic. Peer-to-peer traffic can be sent in a direct link setup (DLS) between the source STA and the destination STA (e.g., directly between them). In certain representative embodiments, the DLS can use 802.11e DLS or 802.11z tunneled DLS (TDLS). A WLAN using the Independent BSS (IBSS) mode may not have an AP, and STAs within or using the IBSS (e.g., all of the STAs) can communicate directly with each other. The IBSS mode of communication can be referred to herein as the "ad hoc" communication mode.

[0041] When using the 802.11ac infrastructure operation mode or a similar operation mode, the AP may transmit beacons on a fixed channel such as the primary channel. The primary channel may be of a fixed width (e.g., a 20 MHz bandwidth) or a dynamically set width. The primary channel may be the operating channel of the BSS and may be used by the STA to establish a connection with the AP. In certain representative embodiments, Carrier Sense Multiple Access with Collision Avoidance (CSMA / CA) may be implemented, for example, in an 802.11 system. In the case of CSMA / CA, STAs including the AP (e.g., all STAs) may sense the primary channel. If the primary channel is sensed / detected as busy by a particular STA and / or determined to be so, the particular STA may back off. Only one STA (e.g., only one station) may transmit at any given time in a given BSS.

[0042] High Throughput (HT) STAs may use a 40 MHz wide channel for communication, and this 40 MHz wide channel may be formed, for example, through a combination of the primary 20 MHz channel and an adjacent or non - adjacent 20 MHz channel.

[0043] A Very High Throughput (VHT) STA may support channels with widths of 20 MHz, 40 MHz, 80 MHz, and / or 160 MHz. The above-mentioned 40 MHz and / or 80 MHz wide channels may be formed by combining a plurality of consecutive 20 MHz channels. A 160 MHz channel may be formed by combining eight consecutive 20 MHz channels or by combining two non-consecutive 80 MHz channels, which may be referred to as an 80+80 configuration. In the case of the 80+80 configuration, after channel encoding, the data may pass through a segment parser that may divide the data into two streams. The Inverse Fast Fourier Transform (IFFT) process and time domain processing may be performed separately for each stream. The streams may be mapped to two 80 MHz channels, and the data may be transmitted by the transmitting STA. At the receiver of the receiving STA, the operations described above for the 80+80 configuration may be reversed, and the combined data may be transmitted to the Medium Access Control (MAC).

[0044] The sub-1 GHz operating modes are supported by 802.11af and 802.11ah. The channel operating bandwidth and carriers are reduced in 802.11af and 802.11ah compared to those used in 802.11n and 802.11ac. 802.11af supports bandwidths of 5 MHz, 10 MHz, and 20 MHz in the TV White Space (TVWS) spectrum, and 802.11ah supports bandwidths of 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz using the non-TVWS spectrum. According to an exemplary embodiment, 802.11ah may support meter type control / machine type communications (MTC) such as MTC devices in a macro coverage area. The MTC device may have certain capabilities, including, for example, support for a specific and / or limited bandwidth (e.g., support only therefor). The MTC device may include a battery having a battery life exceeding a threshold (e.g., to maintain a very long battery life).

[0045] A WLAN system that can support multiple channels and channel bandwidths such as 802.11n, 802.11ac, 802.11af, and 802.11ah includes channels that can be designated as primary channels. The primary channel may have a bandwidth equal to the maximum common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel can be set and / or restricted by a STA among all STAs operating in a BSS that supports the minimum bandwidth operation mode. In the example of 802.11ah, the primary channel can be 1 MHz wide for a STA (e.g., an MTC type device) that supports the 1 MHz mode (e.g., supports only that) even when the AP and other STAs in the BSS support 2 MHz, 4 MHz, 8 MHz, 16 MHz, and / or other channel bandwidth operation modes. Carrier sensing and / or Network Allocation Vector (NAV) setting can depend on the state of the primary channel. For example, when the primary channel is busy, a STA transmitting to the AP (supporting only the 1 MHz operation mode) may consider all of the available frequency band as busy even if most of the available frequency band is idle.

[0046] In the United States, the available frequency band that can be used by 802.11ah is 902 MHz to 928 MHz. In South Korea, the available frequency band is 917.5 MHz to 923.5 MHz. In Japan, the available frequency band is 916.5 MHz to 927.5 MHz. The total bandwidth available for 802.11ah is 6 MHz to 26 MHz depending on the country code.

[0047] FIG. 1D is a system diagram illustrating RAN104 and CN106 according to one embodiment. As described above, RAN104 can communicate with WTRU102a, 102b, 102c via air interface 116 using NR radio technology. RAN104 can also communicate with CN106.

[0048] RAN 104 may include gNBs 180a, 180b, and 180c, but it should be understood that RAN 104 may include any number of gNBs while maintaining consistency with one embodiment. Each of gNBs 180a, 180b, and 180c may include one or more transceivers for communicating with WTRUs 102a, 102b, and 102c via air interface 116. In one embodiment, gNBs 180a, 180b, and 180c may implement MIMO technology. For example, gNBs 180a and 108b may utilize beamforming to transmit and / or receive signals to / from gNBs 180a, 180b, and 180c. Thus, gNB 180a may transmit and / or receive radio signals from / to WTRU 102a, for example, using multiple antennas. In one embodiment, gNBs 180a, 180b, and 180c may implement carrier aggregation technology. For example, gNB 180a may transmit multiple component carriers to WTRU 102a (not shown). A subset of these component carriers may be on unlicensed spectrum, and the remaining component carriers may be on licensed spectrum. In one embodiment, gNBs 180a, 180b, and 180c may implement Coordinated Multi-Point (CoMP) technology. For example, WTRU 102a may receive coordinated transmission from gNB 180a and gNB 180b (and / or gNB 180c).

[0049] WTRUs 102a, 102b, and 102c may communicate with gNBs 180a, 180b, and 180c using transmissions associated with an extensible numerology. For example, the OFDM symbol interval and / or the OFDM sub-carrier interval may vary for different transmissions, different cells, and / or different portions of the radio transmission spectrum. WTRUs 102a, 102b, and 102c may communicate with gNBs 180a, 180b, and 180c using sub-frames or transmission time intervals (TTIs) of various or extensible lengths (e.g., including various numbers of OFDM symbols and / or varying durations of absolute time of varying lengths).

[0050] gNBs 180a, 180b, and 180c may be configured to communicate with WTRUs 102a, 102b, and 102c in a stand-alone configuration and / or a non-stand-alone configuration. In a stand-alone configuration, WTRUs 102a, 102b, and 102c may communicate with gNBs 180a, 180b, and 180c without accessing other RANs (e.g., eNode-Bs 160a, 160b, and 160c, etc.). In a stand-alone configuration, WTRUs 102a, 102b, and 102c may utilize one or more of gNBs 180a, 180b, and 180c as a mobility anchor point. In a stand-alone configuration, WTRUs 102a, 102b, and 102c may communicate with gNBs 180a, 180b, and 180c using signals in an unlicensed band. In a non-stand-alone configuration, WTRUs 102a, 102b, and 102c may communicate with and connect to gNBs 180a, 180b, and 180c while also communicating with and connecting to another RAN such as eNode-Bs 160a, 160b, and 160c. For example, WTRUs 102a, 102b, and 102c may implement a DC principle for communicating with one or more gNBs 180a, 180b, and 180c and one or more eNode-Bs 160a, 160b, and 160c substantially simultaneously. In a non-stand-alone configuration, eNode-Bs 160a, 160b, and 160c may function as a mobility anchor for WTRUs 102a, 102b, and 102c, while gNBs 180a, 180b, and 180c may provide additional coverage and / or throughput for serving WTRUs 102a, 102b, and 102c.

[0051] Each of gNBs 180a, 180b, and 180c can be associated with a specific cell (not shown) and can be configured to handle radio resource management decisions, handover decisions, user scheduling in UL and / or DL, support for network slices, DC, interaction between NR and E-UTRA, routing of user plane data to user plane functions (UPFs) 184a, 184b, routing of control plane information to access and mobility management functions (AMFs) 182a, 182b, etc. As shown in FIG. 1D, gNBs 180a, 180b, and 180c can communicate with each other via the Xn interface.

[0052] CN 106 shown in FIG. 1D can include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one session management function (SMF) 183a, 183b, and optionally data networks (DNs) 185a, 185b. Although the foregoing elements are shown as part of CN 106, it will be understood that any of these elements can also be owned and / or operated by entities other than the CN operator.

[0053] AMF 182a and 182b can be connected to one or more of gNBs 180a, 180b, and 180c in RAN 104 via the N2 interface and can function as control nodes. For example, AMF 182a and 182b can perform roles such as user authentication of WTRUs 102a, 102b, and 102c, support for network slicing (e.g., handling different protocol data unit (PDU) sessions with different requirements), selection of specific SMFs 183a and 183b, management of the registration area, termination of non-access stratum (NAS) signaling, and mobility management. Network slicing can be used by AMF 182a and 182b to customize the CN support for WTRUs 102a, 102b, and 102c based on the type of service being utilized by WTRUs 102a, 102b, and 102c. For example, different network slices can be established for different use cases such as services that rely on ultra-reliable low latency (URLLC) access, services that rely on enhanced massive mobile broadband (eMBB) access, services for MTC access, and the like. AMF 182a and 182b can provide control plane functions for switching between RAN 104 and other RANs (not shown) that use other radio technologies such as non-3GPP access technologies like LTE, LTE-A, LTE-A Pro, and / or WiFi.

[0054] SMF183a and 183b can be connected to AMF182a and 182b in CN106 via the N11 interface. SMF183a and 183b can also be connected to UPF184a and 184b in CN106 via the N4 interface. SMF183a and 183b can select and control UPF184a and 184b and configure the routing of traffic through UPF184a and 184b. SMF183a and 183b can perform other functions such as the function of managing and allocating UE IP addresses, the function of managing PDU sessions, the function of implementing policies and controlling QoS, and the function of providing DL data notifications. The PDU session type can be IP-based, non-IP-based, Ethernet-based, etc.

[0055] UPF184a and 184b can be connected to one or more of gNB180a, 180b, and 180c in RAN104 via the N3 interface, thereby providing WTRU102a, 102b, and 102c with access to a packet-switched network such as the Internet 110 to facilitate communication between WTRU102a, 102b, and 102c and IP-corresponding devices. UPF184 and 184b can perform other functions such as packet routing and forwarding, implementation of user plane policies, support for multi-home PDU sessions, processing of user plane QoS, buffering of DL packets, and provision of mobility anchoring.

[0056] CN106 may facilitate communication with other networks. For example, CN106 may include or communicate with an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that functions as an interface between CN106 and PSTN108. Additionally, CN106 may provide access to other network 112 for WTRU102a, 102b, 102c, and other network 112 may include other wired and / or wireless networks owned and / or operated by other service providers. In one embodiment, WTRU102a, 102b, 102c may be connected to local DN185a, 185b through UPF184a, 184b via an N3 interface to UPF184a, 184b and an N6 interface between UPF184a, 184b and DN185a, 185b.

[0057] In view of FIGS. 1A-1D and the corresponding descriptions of FIGS. 1A-1D, one or more or all of the functions described herein with respect to one or more of WTRU102a-d, base stations 114a-b, eNode-Bs 160a-c, MME162, SGW164, PGW166, gNBs 180a-c, AMFs 182a-b, UPFs 184a-b, SMFs 183a-b, DNs 185a-b, and / or any other devices described herein may be performed by one or more emulation devices (not shown). An emulation device may be one or more devices configured to emulate one or more or all of the functions described herein. For example, an emulation device may be used to test other devices and / or simulate network and / or WTRU functionality.

[0058] An emulation device may be designed to implement one or more tests of other devices in a laboratory environment and / or an operator network environment. For example, one or more emulation devices may be fully or partially implemented and / or deployed as part of a wired and / or wireless communication network to test other devices within the communication network and may execute one or more or all functions while being implemented and / or deployed. One or more emulation devices may execute one or more or all functions while being temporarily implemented / deployed as part of a wired and / or wireless communication network. An emulation device may be directly coupled to another device for the purpose of testing and / or conducting tests using over-the-air wireless communication.

[0059] One or more emulation devices may execute one or more functions including all while not being implemented / deployed as part of a wired and / or wireless communication network. For example, an emulation device may be utilized in a test scenario in a test laboratory and / or in a wired and / or wireless communication network that is not deployed (e.g., for testing) to implement tests of one or more components. One or more emulation devices may be test equipment. Direct RF coupling and / or wireless communication via an RF circuit (which may include one or more antennas) may be used by an emulation device to transmit and / or receive data.

[0060] The WTRU may determine the mapping of the actual repetition of a nominal repetition according to channel access procedure (e.g., listen before talk (LBT)) timing and channel occupancy time (COT) or fixed frame period (FFP) configuration / timing.

[0061] The WTRU may determine the content and transmission parameters of the PUSCH repetition according to at least one of the repetition timing, the associated LBT timing, the duration of the PUSCH repetition, the position of adjacent PUSCH repetitions, the COT timing, the result of the previous LBT, the FFP idle period timing, the identification of the COT initiator, the previous drop of the transport block (TB), or the cancellation indication.

[0062] The WTRU may trigger the repetition of the PUSCH transmission until the receipt of the hybrid automatic repeat request (HARQ)-ACK, until the expiration of the timer, or until a new TB can be transmitted.

[0063] The WTRU may transmit multiple repetitions of the TB in a set of non-adjacent slots to enable multi-TTI scheduling with repetition.

[0064] Repetition may be used to improve the reliability of transmission without requiring the overhead of HARQ-ACK feedback. In the case of ultra-reliable low-latency communication (URLLC), two types of repetition, namely repetition type A and repetition type B, are defined.

[0065] Figure 2 shows an example of repetition type A. In Figure 2, there are multiple slots separated by slot boundaries. The transmission repetition (e.g., the PUSCH transport block (TB)) may be transmitted once in each slot. Each slot may contain only one repetition, and the time domain for the repetition is the same in those slots. The start and length indicator value (SLIV) is the same for all slots.

[0066] Repetition type A can be a simple way to achieve repetition. However, for shorter allocations (i.e., sub - slot allocations), such repetition may not achieve optimal latency. It may be beneficial to enable sub - slot repetition. Figure 3 shows an example of repetition type B. In Figure 3, each slot has six symbols (which can be for uplink or downlink as indicated by "U" or "D" respectively), and each slot is separated by a slot boundary. PUSCH transmission can be repeated within a slot.

[0067] Nominal repetition can be defined by a specific time - domain resource allocation (TDRA) / transport block size (TBS) combination. The WTRU can receive information regarding nominal repetition. The WTRU can receive information indicating the number of nominal repetitions and the number of symbols in which PUSCH transmission can be repeated in nominal repetition. Nominal repetition can be interrupted, for example, by DL symbols or slot boundaries. Nominal repetition can be divided into actual repetitions such that each actual repetition is not interrupted by DL symbols or slot boundaries. Thus, in a repetition scheme with K nominal repetitions, there can be more than K actual repetitions. For example, in Figure 3, K = 4 and the nominal repetition is 4 symbols. In this case, there are 5 actual repetitions.

[0068] Repetition type A can be modified to allow multiple repetitions within a slot. Figure 4 shows a modification of repetition type A with two repetitions within a slot. This can, for example, reduce the required number of LBTs needed for a set of repetitions. However, each slot has the same number of repetitions and their positions are fixed within the slot.

[0069] Multi-TTI scheduling can reduce the signaling required for multiple uplink grants. In multi-TTI scheduling, a new TB is transmitted in a set of slots. FIG. 5 shows an example of multi-TTI scheduling in which new (i.e., different) TBs (e.g., TB1 to TB6) are transmitted in slots 1 to 6, respectively.

[0070] Repetition (e.g., PUSCH repetition) can be advantageous for improving robustness in the unlicensed spectrum. Sub-slot repetition for the unlicensed spectrum can have limitations such that each slot can have a similar resource mapping. However, this approach does not handle dynamic TDD slot formats well and is not flexible for different PUSCH allocation sizes. Repetition type B can have advantages but has not been specified considering the unlicensed spectrum. Therefore, a method is needed to enable repetition type B in the unlicensed spectrum to handle the effects of LBT, COT, and FFP time.

[0071] Multi-TTI scheduling can be beneficial as it reduces the need for signaling. However, a method is needed to enable multi-TTI scheduling with repetition that can enable reduced signaling overhead in combination with robust and low-latency transmission.

[0072] A WTRU can be configured to perform a set of repetitions (e.g., repetitions for a TB). The WTRU can use a channel access procedure (e.g., LBT) before at least one repetition. The channel access procedure or LBT can be used interchangeably herein.

[0073] The WTRU can determine when to perform LBT based on the number of repetitions. In one example, the WTRU can perform LBT before a particular repetition (e.g., the first repetition). In one example, the WTRU may perform LBT before all repetitions. In one example, the WTRU may perform LBT before every nth repetition. Here, n may be configurable.

[0074] The WTRU may determine when to perform LBT based on the gap preceding the repetition. For example, if two consecutive repetitions are transmitted in adjacent symbols, the WTRU may not need to perform LBT before the second repetition. If two repetitions have a gap between them, the WTRU may perform LBT before the second repetition.

[0075] The WTRU may determine when to perform LBT based on the size of the gap between repetitions. For example, the WTRU may perform LBT before the second repetition if the gap between two consecutive repetitions is greater than a value x. The value x may be configurable.

[0076] The WTRU may determine when to perform LBT based on the cause or purpose of the gap between consecutive repetitions. For example, the WTRU may perform LBT before the second repetition depending on the cause of the gap between the first and second consecutive repetitions. The cause of the gap may include, for example, at least one of a DL symbol, a flexible symbol dynamically or semi-statically switched to DL, an orphan UL symbol, an idle period of a fixed frame period (FFP), a cancelled transmission (e.g., as indicated via UL CI), a change in COT parameters, or a dropped transmission due to a failed LBT.

[0077] The WTRU may determine when to perform LBT based on frequency hopping. For example, if frequency hopping is used between consecutive repetitions, the WTRU may perform LBT before the first repetition after the frequency hop.

[0078] The WTRU may determine when to perform LBT based on beam changes. For example, if the transmission beam changes between successive repetitions, the WTRU may perform LBT before the first repetition that occurs after the beam change.

[0079] The WTRU may determine when to perform LBT based on COT timing. For example, if successive repetitions are transmitted at different COTs, the WTRU may perform LBT before the second repetition and may start a new COT. In one example, if the repetition resources overlap with the end of a COT, the WTRU may perform LBT before the repeated transmission and may start a new COT.

[0080] The WTRU may determine when to perform LBT depending on who started the COT. For example, if the repetition is transmitted in a COT started by the WTRU, the WTRU may determine a first set of LBT opportunities. If the repetition is transmitted in a COT started by the gNB, the WTRU may determine a second set of LBT opportunities.

[0081] The WTRU may determine when to perform LBT based on FFP timing. For example, if successive repetitions are transmitted at different FFP, the WTRU may perform LBT before the second repetition.

[0082] The WTRU may determine when to perform LBT based on previous LBT results. For example, if LBT failed before a previous repetition, the WTRU may perform LBT before the repetition. In one example, the WTRU may perform LBT before the repetition based on the quantitative performance of LBT for a previous repetition. For example, the WTRU may have a first energy detection threshold for determining whether it can transmit. The WTRU may also maintain energy detection measurements and determine whether LBT is required before subsequent repeated transmissions based on the absolute value (or compared to a second energy detection threshold).

[0083] A WTRU may receive an indication that a resource (e.g., a time or frequency unit or a beam) may not be used for repeated transmission. Such a resource may be considered a dynamically indicated invalid resource. The indication can notify the WTRU of a set of invalid resources, as well as the type of channel access required to resume transmission after the occurrence of such invalid resources. For example, the WTRU may receive an indication that a first resource may not be used for repeated transmission. Not transmitting on such a resource may lead to a gap (e.g., a new gap or an extension of an existing gap). The WTRU may determine the type of channel access (e.g., whether to use LBT, the type of LBT, the parameters associated with LBT) from the indication. In one embodiment, the WTRU may be configured (e.g., semi-statically configured) with or receive information regarding the behavior it uses to access the channel after such dynamically invalid resources are configured.

[0084] The WTRU may receive an indication of an invalid resource or associated channel access in DCI (e.g., DCI that schedules a set of repetitions). The indication may explicitly indicate a set of resources for which repeated transmission is invalid. In one embodiment, the indication may be a bitfield that maps to a configurable set of patterns of invalid resources or channel access types.

[0085] The WTRU may be configured with, or receive information on, a set of resources (e.g., time instances or frequency regions or beams) as to when to perform LBT. When the WTRU is transmitting a set of repetitions, the WTRU may determine that any one resource within the configured set of resources as to when to perform LBT should be considered as an invalid symbol for repeated transmission. The WTRU may perform LBT using one of the resources within the configured set of resources to obtain an unauthorized channel for one or more repeated transmissions. For example, the WTRU may select a resource from the configured set of resources and perform LBT if such a resource occurs before an actual or nominal repetition (e.g., in the immediately preceding symbol). The WTRU may perform LBT on one resource from the set of resources, for example, if there is no ongoing COT.

[0086] The WTRU may be configured with a set of nominal repetitions. The WTRU may determine a set of symbols in which each nominal repetition may occur.

[0087] The WTRU may determine whether the set of symbols of the nominal repetition is valid depending on whether LBT is required before the repetition. For example, if LBT is required before repeated transmission, the first n symbols of the repetition may be reserved for LBT. In one example, if LBT is required before repeated transmission, the last n symbols of the previous repetition may be reserved for LBT.

[0088] The WTRU may determine whether a set of nominal repeated symbols is valid according to the COT boundary timing. For example, if the COT ends at one of the repeated symbols, the WTRU may not need to transmit with a set of n subsequent symbols in the repetition. In another example, if the COT ends at a symbol preceding the repetition, based on the time of COT end, the WTRU may determine a set of m symbols at the start of a subsequent repetition that may not be used for repeated transmission.

[0089] The WTRU may determine whether a set of nominal repeated symbols is valid according to the FFP idle period timing. For example, if an FFP idle period occurs during the repetition, the symbols overlapping with the idle period may not need to be used for that repeated transmission.

[0090] The WTRU may determine whether a set of nominal repeated symbols is valid according to the previous LBT result. For example, based on the LBT result for a previous repetition, the WTRU may determine a set of symbols that may be used for subsequent repeated transmission.

[0091] When the nominal repetition has one or more invalid symbols occurring during that nominal repetition, the WTRU may split or segment that repetition into a plurality of actual repetitions. Each actual repetition may be the entire transmission of a TB (e.g., using rate matching) or a segment of a TB. All segments of the TB may be transmitted in a set of actual repetitions comprising the nominal repetition.

[0092] Figure 6 shows an example of a COT that ends during a repetition. After the COT ends, the WTRU may use n symbols (n = 1 in Figure 6) for LBT to restart the COT and continue transmitting repetitions. For the repetition in which the COT ends (i.e., nominal repetition 3 in Figure 6), the WTRU may use two actual repetitions for the nominal repetition. In an embodiment, the WTRU may segment the repetition into two parts, transmit the first part in the first COT, and transmit the second part in the second COT.

[0093] The WTRU may divide a nominal repetition into a plurality of actual repetitions according to the COT timing or the FFP idle period timing. The WTRU may segment a nominal repetition into a plurality of segments according to the COT timing or the idle period timing. For example, if the COT ends during a nominal repetition or an FFP idle period occurs during a repetition, the WTRU may divide the nominal repetition and transmit two actual repetitions (e.g., copies of the TB) in two sets of adjacent non-interrupted resources. The two sets of adjacent resources may be separated by the COT boundary timing or the FFP idle period timing and may be separated by the resources used to perform LBT before the second repetition.

[0094] Figure 7 shows an exemplary method (700) for mapping nominal repetitions to actual repetitions. A WTRU may receive information regarding the configuration of nominal repetitions (710). The information may indicate the number of nominal repetitions. The information may indicate the number of symbols to be used for each nominal repetition. The WTRU may determine a set of symbols associated with a nominal repetition (e.g., a first nominal repetition) (720). The WTRU may determine the set of symbols associated with a nominal repetition according to at least one of a start symbol of one of the nominal repetitions (e.g., the first nominal repetition), the total number of repetitions, the number of symbols per repetition, the repetition number (e.g., whether the nominal repetition is the first or second or third, etc.), the SLIV received in a UL grant (e.g., in a DCI or RRC configuration), the SCS of the repetition, whether frequency hopping is used, the COT configuration, or the COT initiator (e.g., a COT initiated by the WTRU or a COT initiated by the gNB). The WTRU may transmit the number of actual repetitions (730). The number of actual repetitions may be greater than the number of nominal repetitions. The actual repetitions may be transmitted within one or more symbols (e.g., consecutive symbols) associated with the nominal repetition. The actual repetition transmission may be based on the occurrence of an event within the set of symbols associated with the nominal repetition. The event may be, for example, a COT end, a channel access resource, a channel access procedure result, an FFP idle period start time, or an FFP idle period end time. The set of symbols associated with the nominal repetition may comprise one or more subsets of consecutive uplink symbols. A subset of consecutive uplink symbols may comprise at least two symbols. One subset of consecutive uplink symbols may not overlap with another subset of consecutive uplink symbols. The WTRU may transmit an actual repetition (e.g., a first actual repetition) in the uplink symbols of the subset of consecutive uplink symbols prior to the occurrence of the event. The WTRU may perform a channel access procedure (e.g., LBT).If the channel access procedure is successful, after the occurrence of the event, the WTRU may transmit another actual repetition (e.g., the second actual repetition) after the first actual repetition in a subset of consecutive uplink symbols of the uplink symbols. If the channel access procedure fails, the WTRU may execute a second channel access procedure in the next symbol. If the second channel access procedure is successful, after the occurrence of the event, the WTRU may transmit another actual repetition after the first actual repetition in a subset of consecutive uplink symbols of the uplink symbols. If the second channel access procedure fails, the WTRU may continue to execute the channel access procedure until successful and then transmit an actual repetition.

[0095] The WTRU may perform LBT before at least one repeated transmission. In one embodiment, the WTRU may determine that the channel is busy and may not transmit at least one subsequent transmission (e.g., a repetition). Each nominal or actual repetition may be associated with a set of possible start times. If the WTRU does not need to perform LBT before the first start time of the repetition, the WTRU may transmit the repetition using the first start time. If the WTRU needs to perform LBT before transmitting the repetition, the WTRU may perform a first LBT procedure before the first start time. Based on the first LBT procedure, if it is determined that the channel is idle and transmission is possible, the WTRU may transmit the repetition starting at the first start time. Based on the first LBT procedure, if it is determined that the channel is busy, the WTRU may perform a second LBT procedure before the second start time. Based on the second LBT procedure, if it is determined that the channel is idle and transmission is possible, the WTRU may transmit the repetition starting at the second start time. Based on the second LBT procedure, if it is determined that the channel is busy, the WTRU may perform a third LBT procedure before the third start time. The WTRU may continue to perform additional LBT if it is determined that the channel is busy based on the current LBT.

[0096] The WTRU may indicate which LBT procedure was successful for the repeated transmission. The indication may be provided to the network (e.g., gNB). For example, the indication may be provided in the repeated or subsequent repeated CG-UCI.

[0097] The WTRU may use frequency hopping between repetitions. The frequency hopping may ensure that the WTRU has repetitions scheduled for different LBT bandwidths (BW) or channels, which may increase the channel access probability. The WTRU may be configured with an LBT BW hopping pattern or may receive its configuration information. Such configuration may be semi-static or dynamic. For example, the WTRU may receive configuration information in the DCI that schedules a set of repetitions.

[0098] The WTRU may determine a set of invalid symbols associated with the frequency hop. For example, the invalid symbols may affect the mapping of the first repetition transmitted after the frequency hop (e.g., immediately after). Such a set of invalid symbols may be used by the WTRU to perform LBT in the new LBT BW.

[0099] The WTRU may perform LBT after the frequency hop. The WTRU may perform LBT after the frequency hop if the hop moves the transmission to a frequency region within the new LBT BW (i.e., compared to the frequency region of the previous hop).

[0100] The WTRU may perform LBT before a set of repetitions. Such an LBT procedure may be applicable to the transmission of subsequent sets of repetitions.

[0101] A WTRU that performs LBT before a repeating set may perform LBT for at least one of the LBT BWs that cover the resources of the next repetition or the LBT BWs that cover all the resources of the repetitions in the repeating set.

[0102] In one embodiment, the WTRU may perform LBT on the LBT BW of the repeating set before transmitting the repeating set. The WTRU may not need to perform LBT at each frequency hop. In one embodiment, the WTRU may perform a first LBT of a first LBT type (e.g., LBT type 4 or full LBT) across the LBT BW of the repeating set before transmitting the repeating set, and perform a second LBT of a second LBT type (e.g., LBT type 2 or short LBT) only across the LBT BW of the transmission that occurs at each frequency hop or after the frequency hop.

[0103] The WTRU may be composed of multiple LBT types. Each LBT type may have different channel access assessment parameters (e.g., energy detection threshold, contention window size, clear channel assessment slot duration, etc.).

[0104] The WTRU may determine the LBT type to be used before a nominal or actual repeated transmission based on the COT timing. For example, the WTRU may perform a first type of LBT (e.g., LBT type 4) before the repetition if the COT ends before the repeating timing or ends during the repeating timing. In one embodiment, the WTRU may determine the type or configuration of the LBT based on the time when the current COT was started (the type may include not performing LBT). For example, the WTRU may determine the type or configuration of the LBT based on whether the current COT was started before the repeating set or during the transmission of the repeating set.

[0105] The WTRU may determine the LBT type to use before a nominal or actual repeated transmission by a COT initiator. For example, the WTRU may determine the type of LBT according to the node that first initiated the COT to be repeatedly transmitted.

[0106] The WTRU may determine the LBT type to use before a nominal or actual repeated transmission according to the COT status. For example, if there is an ongoing COT, the WTRU may perform a first type or configuration of LBT (the type may include not performing LBT), and if there is no ongoing COT and a COT needs to be started, the WTRU may perform a second type or configuration of LBT.

[0107] The WTRU may determine the LBT type to use before a nominal or actual repeated transmission according to the gap size. For example, the WTRU may determine the type of LBT to use before a transmission according to the gap size between that transmission and the previous transmission.

[0108] The WTRU may determine the LBT type to use before a nominal or actual repeated transmission according to the cause of the gap. For example, the WTRU may determine the type of LBT to use before a transmission according to the cause of the gap between that transmission and the previous transmission. The cause of the gap may include a DL symbol, a flexible symbol dynamically or semi-statically switched to the DL, an orphan UL symbol, an idle period of a fixed frame period (FFP), a cancelled transmission (e.g., by indication via a UL CI), a change in COT parameters, or a dropped transmission due to a failed LBT.

[0109] The WTRU may determine the LBT type to be used before a nominal or actual repeated transmission depending on whether the transmission is for a TB that is different from a preceding (e.g., immediate preceding) repeated transmission. For example, the WTRU may transmit multiple TBs. Each TB may have multiple repetitions. The WTRU may determine the LBT type when two consecutive repetitions are for the same or different TBs.

[0110] The WTRU may determine the content to include in a repetition (i.e., nominal repetition or actual repetition). In a repeated transmission, the WTRU may include, for example, the following elements, i.e., CG-UCI, demodulation reference signal (DM-RS), UCI (e.g., scheduling request (SR), channel state information (CSI), HARQ-ACK, or at least one of the TBs).

[0111] The WTRU may determine which content should be included in the repeated transmission based on the number of repetitions. For example, the WTRU may include CG-UCI in the first repetition (e.g., only in the first repetition). In one example, the WTRU may include CG-UCI or UCI in the nth repetition or every mth repetition.

[0112] The WTRU may determine which content should be included in the repeated transmission based on the repetition size. For example, the WTRU may include CG-UCI if the repetition duration is greater than a value x. The value of x may be fixed or may depend on the nominal repetition size. For example, if the nominal repetition is of size n and due to invalid resources, the actual repetition is of size m, the UE may include CG-UCI if m > n - k, where k may be configurable or fixed.

[0113] The WTRU may determine which content to include in the repeated transmission based on whether the repetition is divided or segmented. For example, the WTRU may include the CG-UCI or DM-RS or UCI once per nominal repetition. If the nominal repetition is divided or segmented into multiple actual repetitions, the WTRU may transmit the CG-UCI or DM-RS or UCI in a single actual repetition. The WTRU may determine that the actual repetition containing the CG-UCI or DM-RS or UCI is the y-th (e.g., first or last) repetition. The WTRU may determine that the actual repetition containing the CG-UCI or DM-RS or UCI is an actual repetition having a duration greater than value x.

[0114] The WTRU may determine which content to include in the repeated transmission based on whether the repetition is preceded by LBT (e.g., immediately preceded). For example, the WTRU may include the CG-UCI if an LBT procedure is performed before the repetition (e.g., after the immediately preceding repetition).

[0115] The WTRU may determine which content to include in the repeated transmission based on the COT timing. For example, the WTRU may include the CG-UCI in the repetition if a new COT is started before the repeated transmission or during the time between that repetition and the preceding repetition (e.g., the immediately preceding repetition).

[0116] The WTRU may determine which content to include in the repeated transmission based on the number of repetitions within a slot. For example, the WTRU may include the CG-UCI or DM-RS or UCI in a single repetition within the slot. The WTRU may include the CG-UCI or DM-RS or UCI in the first repetition of the slot.

[0117] The WTRU may determine which content to include in the retransmission based on the HARQ process ID. For example, the WTRU may include CG-UCI if the HARQ process ID of the TB has changed from a previous retransmission.

[0118] The WTRU may determine which content to include in the retransmission based on the transmission priority. For example, the WTRU may determine whether to include CG-UCI or UCI according to the priority of the UCI or TB.

[0119] The WTRU may determine which content to include in the retransmission based on a previously dropped transmission. For example, if the CG-UCI was dropped from a previous retransmission, it may be included in a subsequent retransmission. In one example, if a previous transmission was dropped (e.g., due to a failed LBT for reception of UL CI), the WTRU may include the CG-UCI in a subsequent retransmission.

[0120] The WTRU may determine which content to include in the retransmission based on whether rate matching is used on the TB.

[0121] The WTRU may determine which content to include in the retransmission based on whether the frequency or beam has changed. For example, the WTRU may include CG-UCI if the retransmission is sent after frequency hopping or after a change in the transmission beam.

[0122] The WTRU may determine which elements to include in the repeated transmission according to a plurality of transmission criteria described herein. As an example, if the priority of the TB is high (e.g., greater than a threshold or a configured value), the WTRU may determine that the CG-UCI may be included in all repetitions. In one example, if the priority of the UCI is high (e.g., greater than a threshold or a configured value), the WTRU may include the UCI in the first set of repetitions, and if the priority of the UCI is low (e.g., less than a threshold or a configured value), the WTRU may include the UCI in the second set of repetitions.

[0123] The WTRU may drop an element from the repetition and include another element. For example, if the UCI has a high priority (e.g., greater than a threshold or a configured value), the WTRU may drop the CG-UCI and transmit only the UCI along with the TB. When an element is dropped to enable the transmission of another (e.g., higher priority) element, the WTRU may include the dropped element in subsequent repetitions.

[0124] The CG-UCI may be transmitted in a plurality of repetitions of a set of repetitions. The content of the CG-UCI may remain the same for each repetition. In one example, if the CG-UCI is transmitted in more than one repetition, the CG-UCI content may change for each CG-UCI transmission. For example, the first CG-UCI in a set of repetitions may include the information required (e.g., all the information required), and any subsequent CG-UCI within the set of repetitions may include only the changes or updates to the CG-UCI. In one example, the first CG-UCI in a set of repetitions may include the information required (e.g., all the information required), and subsequent CG-UCI may include only the information relevant to that repetition. For example, if the HARQ process ID may change for each repetition, the CG-UCI may include the HARQ process ID relevant to the associated repetition, but any other content that is fixed for all repetitions may be transmitted by the WTRU only once per set of repetitions.

[0125] The content of the CG-UCI can be determined by rules similar to those described herein to determine whether it includes the CG-UCI. For example, the content of the CG-UCI can depend on the actual repetition size and can be related to the nominal repetition size.

[0126] The content of the CG-UCI can depend on whether it is multiplexed with other UCIs. The content of the CG-UCI multiplexed with other UCIs can depend on the priority of the CG-UCI or the TB, or the priority of other UCIs.

[0127] The content of the CG-UCI can include at least one of a HARQ process ID, a number of repetitions, a priority (e.g., a transmission priority or a priority of LBT used before transmission), a redundancy version (RV), a modulation and coding scheme (MCS), a beam ID, a nominal repetition duration, and a DMRS mapping type.

[0128] An orphan symbol can occur when a nominal repetition is divided or segmented into multiple possible actual repetitions and one such possible actual repetition is a single symbol. The division or segmentation can be caused by at least one of a DL symbol, a slot boundary, a COT timing, or an FFP idle period timing.

[0129] The WTRU can use an orphan symbol to transmit one or more elements of a repetition. This can be beneficial for reducing the need for LBT caused by an unused orphan symbol gap. In one example, the WTRU can transmit CG-UCI or DM-RS in an orphan symbol. In such a case, the WTRU may not need to transmit CG-UCI or DM-RS in one or more associated actual repetitions.

[0130] The WTRU may determine whether to transmit on an orphan symbol or which element within the orphan symbol to transmit based on the transmission criteria described herein.

[0131] The orphan symbol may be associated with an actual repetition based on whether both the orphan symbol and the actual repetition are within the same nominal repetition.

[0132] The orphan symbol may be associated with an actual repetition based on the timing of the orphan symbol. For example, the orphan symbol may be associated with the preceding actual repetition. In another example, the orphan symbol may be associated with the subsequent actual repetition.

[0133] The orphan symbol may be associated with an actual repetition based on the duration of the actual repetition. For example, the orphan symbol may be associated with an actual repetition if it has a duration that is less than value x or greater than value y.

[0134] The orphan symbol may be associated with an actual repetition based on slot timing. For example, if the orphan symbol and the actual transmission are within the same slot, the orphan symbol may be associated with the actual transmission.

[0135] The orphan symbol may be associated with an actual repetition based on COT status. For example, the WTRU may determine to transmit on the orphan symbol if an ongoing COT exists or if no ongoing COT exists.

[0136] The orphan symbol can be associated with the actual repetition based on the COT indicator. For example, the WTRU can determine to transmit on the orphan symbol depending on which node (e.g., the WTRU or the gNB) initiated the ongoing COT. For example, if the gNB or another WTRU initiated the COT, the WTRU may not need to transmit on the orphan symbol. If the WTRU initiated the COT, the WTRU can transmit on the orphan symbol.

[0137] The WTRU can determine whether to use the orphan symbol to transmit an element according to a gap that can be created when the orphan symbol is not used. For example, if not transmitting on the orphan symbol creates a gap between repetitions greater than value x (e.g., a gap that requires LBT before the next repeated transmission), the WTRU can transmit one or more elements on the orphan symbol. The WTRU can determine whether to use the orphan symbol for transmission based on whether two orphan symbols are adjacent. For example, if two orphan symbols are adjacent, the WTRU can transmit on at least one of the orphan symbols.

[0138] Figure 8 shows an example of two adjacent orphan symbols, both occurring in nominal repetition 2. In this case, the WTRU can determine that the gap created by one or more adjacent orphan symbols is greater than a threshold. The threshold can be configured or fixed, or the WTRU can receive an indication of the threshold. The indication can be received, for example, via DCI, MAC, or RRC configuration. The WTRU can transmit a repeated element (e.g., CG-UCI, DM-RS, UCI, or TB) in at least one of the orphan symbols. This can be beneficial to maintain the COT and reduce the need for LBT before transmitting the rest of nominal repetition 2.

[0139] The WTRU may transmit the UCI in an orphan symbol. The WTRU may transmit the UCI on the PUSCH in an orphan symbol. In one embodiment, the WTRU may transmit the UCI on the PUCCH when configured with physical uplink control channel (PUCCH) resources within an orphan symbol. In such a case, subsequent repetitions in a nominal repetition (e.g., the associated repetition) may or may not include the UCI on the PUSCH.

[0140] The WTRU may transmit DM-RS on an orphan symbol when it is configured for cross-repetition or cross-slot DM-RS.

[0141] The WTRU may transmit a number of symbols greater than the number of symbols in a nominal repetition in order to continue occupying the channel. The WTRU may transmit more actual repetitions than the number required (e.g., the configured number) to maintain the COT. The WTRU may determine that another new TB has arrived within a specific time before the expiration of the current COT occupied by the WTRU. The WTRU may transmit additional repetitions and / or symbols of the current TB to continue occupying the channel until the next TB arrives at the WTRU buffer and / or can be transmitted. The WTRU may determine TB arrival based on a configured traffic pattern. In one example, the WTRU may already have buffered bits for transmission on a new TB, but transmitting the nominal repetitions for that new TB may require waiting for another UL slot or a different PUSCH opportunity (e.g., after a DL interruption), or the number of UL symbols and / or slots remaining before a DL interruption may not allow the WTRU to transmit the new TB. The WTRU may continue to occupy the channel by transmitting additional symbols and / or repetitions of the current TB, even if it exceeds the configured number of required repetitions and / or symbols within the nominal repetition, until the DL interruption time, until the next FFP IDLE period, until the COT can be shared with the gNB, until it receives a stop indication from the gNB, or until the WTRU can access an uplink slot that may be used to transmit new data, in some cases on the same HARQ process.

[0142] The WTRU can repeat the TB until the time (e.g., CG timer) expires, or until it is determined that x time has elapsed for the HARQ process, or until the HARQ-ACK received equals the ACK on the Downlink Feedback Information (DFI). In one example, the WTRU can continue to occupy the channel with transmissions from a different HARQ process y until a determination is made that the CG retransmission time has elapsed for the pending HARQ process x (e.g., the CG retransmission timer expires). This can enable the WTRU to immediately retransmit the TB and / or repeat the HARQ process x after the determination that the CG retransmission time has elapsed (e.g., upon expiration of the CG retransmission timer).

[0143] The WTRU can repeat the transmission until the configured number of repetitions (e.g., rep K) or until the next downlink slot or downlink symbol. The WTRU can receive an indication from the Downlink Control Information (DCI) or Radio Resource Control (RRC) indicating a configured grant that the WTRU can transmit repetitions until it encounters the next downlink. This can be useful for maintaining a burst of repeated transmissions until the next downlink slot, or until the idle period, or until the COT is released or can be shared with the gNB.

[0144] The WTRU can multiplex the UCI (e.g., CG-UCI on the PUSCH) on the uplink channel that is transmitting additional symbols and / or additional repetitions (e.g., to maintain the COT or until the end of the COT). The UCI can include the number of additional symbols or additional repetitions for the current COT or for the bundle size.

[0145] In one embodiment, the gNB can notify the WTRU of the dynamic number of repetitions and / or symbols used to transmit the actual repetitions during the UL transmission opportunity following the DL in the shared COT, if applicable. For example, in a scenario where TDD divided in a slot or frame is configured as DUUUU-DUUUU, even if the nominal repetition is three symbols (or slots), the WTRU can transmit the actual repetition of four symbols to ensure that the COT is maintained until the next DL symbol or slot, the next FFP or idle period, or until the indicated amount of uplink symbols or slots has elapsed. When the WTRU receives an indication from the gNB, it can transmit additional symbols of the actual repetition, and the number of symbols may be greater than the nominal repetition. When the WTRU receives an indication from the gNB, it can transmit additional repetitions, and the number of repetitions may be greater than the configured number of repetitions. The indication from the gNB may indicate the number of symbols applicable to the remaining repetition(s), the number of symbols applicable to the remaining repetition(s) in the current / shared COT, the number of additional repetitions, or the number of additional repetitions in the current / shared COT.

[0146] The WTRU can transmit a smaller number of UL symbols in the actual repetition than the number of symbols in the nominal repetition. For example, the WTRU can transmit on some symbols or orphan symbols to maintain the COT. The WTRU can be set with a minimum number of symbols. The configuration may be by the upper layer. If the number of symbols in the actual repetition is less than the minimum number of symbols, the WTRU can transmit the repetition but not count it towards the target number of configured repetitions, or the WTRU may not transmit the repetition at all.

[0147] When the WTRU encounters a UL LBT failure, it can defer, skip, or cancel the repetition. When the repetition is transmitted, the WTRU can increment the repetition count.

[0148] When the WTRU encounters a UL LBT failure for a repetition, receives a cancellation indication, or drops a repetition, for example, due to WTRU - to - WTRU / WTRU - internal prioritization, the WTRU can continue the remaining repetitions or terminate the remaining repetition transmissions when it encounters the next transmission opportunity. The WTRU can drop, skip, delay, or cancel a repetition. The WTRU can continue transmitting a repetition if the repetition count is below a predetermined threshold, if the channel is acquired again, and / or if the number of UL symbols per previously transmitted repetition(s) was equal to the nominal repetition. The WTRU can be configured by, for example, RRC, MAC control element (MAC - CE), or DCI with a predetermined threshold.

[0149] The WTRU can receive DCI MAC CE or RRC signaling indicating the resumption of the remaining repetition transmissions, and / or a configured grant that the WTRU can use to continue the remaining repetitions. The WTRU can receive DCI or RRC indicating the HARQ ID that the WTRU can use to transmit the remaining repetitions. The WTRU can receive an explicit indication from the gNB to interrupt or cancel the remaining repetitions while waiting for the next uplink slot to complete a specified number of repetitions. The WTRU can, in some cases, cancel or pause a repetition for a given HARQ process before the repetition count reaches the configured number of repetitions (e.g., rep K). For example, the WTRU can receive a dynamic notification in DCI or MAC - CE, in a COT that may be different from the one used to transmit the initial set of repetitions in some cases, to terminate or pause a repetition from the network in a downlink slot. If the remaining repetitions are dropped due to network signaling (e.g., due to receiving a cancellation indication from the gNB), the WTRU may cancel the remaining repetitions, but if they are dropped due to LBT failure or WTRU internal prioritization, they cannot be cancelled and the gNB cannot recognize that they were dropped / not transmitted.

[0150] The WTRU may transmit the LBT-failed repetitions using different LBT configurations (e.g., Channel Access Priority Class (CAPC), LBT category, or modified LBT parameters), (e.g., based on the number of failed LBTs or LBT failures counted in the MAC layer, etc.).

[0151] The WTRU may change the number of UL symbols and / or slots used to transmit the actual repetition after obtaining another COT to transmit the remaining repetitions. The change may be based on, for example, the available number of UL slots and / or symbols in the new COT, and the available UL resource allocation (e.g., the configuration of the CG in the new COT and / or the allocation of dynamic grants provided in the new COT). The WTRU may include UCI (e.g., CG-UCI) multiplexed on the PUSCH that indicates the HARQ process, the TB index, and / or the RV of the applicable repetition. The WTRU may skip incrementing the RV number if it fails LBT for a repetition within a sequence. The WTRU may indicate in the UCI that a subset of past repetitions has been dropped due to LBT failure or a reduction in priority within the WTRU (e.g., to assist with soft combining). For example, the WTRU may indicate in the CG-UCI transmitted in the first subsequent repetition after the set of dropped repetitions that the previous set of repetitions has been dropped. The indication may include the identification or number of the previous dropped repetitions. The indication may be included in multiple subsequent CG-UCI (e.g., for robustness). A bitmap may be included in the CG-UCI to flag the set of dropped repetitions.

[0152] The UL LBT failure counter or indicator may be maintained for each repetition, or for each set of repetitions, or for each LBT attempt. For example, the UL LBT failure may be incremented by 1 each time the LBT fails, or may be incremented by the number of repetitions (e.g., actual or nominal) dropped due to the LBT failure. If a repetition has multiple start times, the UL LBT failure counter may be incremented if none of the LBT start times are considered valid due to all LBTs having failed. If a nominal repetition is segmented into multiple actual repetitions, the UL LBT failure counter may be incremented each time an attempt to transmit an actual repetition fails, or if all actual repetitions have failed.

[0153] The WTRU may be restricted to transmit repetitions (e.g., type A or type B) based on which device initiated the COT. For example, the WTRU may be restricted to transmit repetitions only for COTs initiated by the gNB, only for COTs initiated by the WTRU, or for both. Whether repetitions are permitted for COTs initiated by the gNB, by the WTRU, or both, may be configured semi-statically by the RRC, or indicated via DCI. The WTRU may be configured to enable repetitions of type A only, type B only, or types A and B based on which device initiated the COT.

[0154] The WTRU may select which COT to transmit repetitions according to the length of the FFP or the remaining FFP duration. For example, if the length of the repeated transmission exceeds the remaining time of the gNB FFP and the WTRU is composed of the next FFP with a duration long enough to accommodate the repeated duration, the WTRU may transmit repetitions on the COT started by the WTRU. If the FFP start time configured by the WTRU occurs in the very distant future, or if the COT FFP duration started by the configured WTRU is insufficient to transmit a complete repetition, the WTRU may rate-match the repetitions to accommodate the remaining gNB FFP duration.

[0155] When the COT started by the WTRU is used for repeated transmission, the WTRU may be composed of COT FFP parameters started by a dedicated WTRU, such as FFP periodicity, start offset, and FFP duration. This configuration may be configured semi-statically via dedicated signaling (e.g., via RRC signaling, via MAC CE, or via DCI). The FFP parameters may be mapped to the repetition type (e.g., type A or B) and / or repetition parameters (e.g., repetition duration and number of repetitions).

[0156] The WTRU may start the COT started by the WTRU if the repeated transmission is scheduled to start immediately after a successful Clear Channel Assessment (CCA) (i.e., at the start of the FFP started by the WTRU). If the WTRU is configured with multiple FFP configurations, the WTRU may select the FFP configuration with an FFP start that aligns with the start of the scheduled repeated transmission. If the start of the scheduled repetition does not align with the start of the FFP start time started by the WTRU, the WTRU may transmit (e.g., padding bits) to start the channel until the scheduled repetition.

[0157] If the IDLE period interrupts the WTRU's repeated transmission, the WTRU can cancel the remaining repeated transmissions. The WTRU can suspend transmission until the completion of the IDLE period and resume repetition at the start of a new FFP. The WTRU can distinguish how the IDLE period affects the repeated transmission process depending on whether the IDLE period was initiated by the gNB or the WTRU. For example, if the IDLE period occurs at the end of an FFP initiated by the WTRU, the WTRU can cancel the remaining repeated transmissions. If the WTRU is sharing a COT initiated by the gNB, the WTRU can suspend transmission until the completion of the IDLE period and resume repeated transmission.

[0158] The WTRU can determine the overlap between PUSCH repetitions of a first priority (e.g., priority index 0) and PUCCH or PUSCH transmissions of a second priority (e.g., priority index 1). It may be beneficial to avoid transmission gaps that would require LBT before subsequent repetitions.

[0159] In one embodiment, the WTRU can cancel the PUSCH repeated transmission of a first priority (e.g., priority index 0) for time symbols where there is an overlap with a transmission of another priority (e.g., priority index 1). For the remaining time symbols, the WTRU can transmit the same modulation symbols and reference signals as if no cancellation had occurred in the overlapping symbols.

[0160] In one embodiment, for the purpose of determining the set of actual repetitions from the nominal repetitions according to the procedure defined for PUSCH repetition type B, the WTRU can consider time symbols with an overlap as "invalid symbols". Symbols without an overlap can be considered "potentially valid" symbols, and the WTRU can define the actual repetitions as a continuous set of potentially valid symbols. The WTRU can transmit the actual repetition of a single symbol in this scenario even otherwise, based on the rules applicable to PUSCH repetition type B.

[0161] In one embodiment, the WTRU may determine the actual repetitions for a set of consecutive symbols with repetitions. The WTRU may multiplex the overlapping transmissions and actual repetitions of priority index 1 into a single transmission. Such an embodiment may be applicable when the transmission of priority index 1 is a PUCCH transmission and multiplexing of UCI of priority index 1 on PUSCH of priority index 0 is supported.

[0162] The WTRU may be configured or granted resources for transmitting a plurality of TBs. Each TB may have a plurality of repetitions. The time resources for each repetition of each TB may be determined based on a mapping rule. The mapping rule may cycle through all the repetitions of a TB first before cycling through all the repetitions of subsequent TBs. The mapping rule may cycle through all the first repetitions of all the TBs before cycling through all the second repetitions of all the TBs.

[0163] FIG. 9 shows an example of the mapping of repetitions when multi-TTI scheduling is used and the transmission cycle is performed first for each TB and then for each repetition. In FIG. 9, there are three TBs, each TB has two repetitions, and each nominal transmission includes five symbols. As shown in FIG. 9, the repetitions of the TBs (repetition 1 of TB1, repetition 1 of TB2, repetition 1 of TB3) are transmitted, and then the second repetitions of the TBs (repetition 2 of TB1, repetition 2 of TB2, repetition 2 of TB3) are transmitted.

[0164] FIG. 10 shows an example of the mapping of repetitions when multi-TTI scheduling is used and the transmission cycle is performed first for each repetition and then for each TB. In FIG. 10, there are three TBs, each TB has two repetitions, and each nominal transmission includes five symbols. As shown in FIG. 10, all repetitions of the first TB are transmitted (repetition 1 of TB1, repetition 2 of TB1), then all repetitions of the second TB are transmitted (repetition 1 of TB2, repetition 2 of TB2), and then all repetitions of the third TB are transmitted (repetition 1 of TB3, repetition 2 of TB3).

[0165] Each of the repetitions shown in FIGS. 9 and 10 may be a nominal repetition, and the nominal repetition may be divided or segmented into a plurality of actual repetitions. In FIG. 9, the nominal repetition TB2,rep 1 is divided into two actual repetitions, the nominal repetition TB3,rep 1 is divided into two actual repetitions, the nominal repetition TB2,rep 2 is divided into two actual repetitions, and the nominal repetition TB3,rep 2 is divided into two actual repetitions. In FIG. 10, the nominal repetition TB1,rep 2 is divided into two actual repetitions, the nominal repetition TB2,rep 1 is divided into two actual repetitions, the nominal repetition TB3,rep 1 is divided into two actual repetitions, and the nominal repetition TB3,rep 2 is divided into two actual repetitions.

[0166] When the WTRU is scheduled in a single TB using repetition, both embodiments (circulating for each TB in FIG. 9 and then for each repetition, and circulating for each repetition first and then for each TB in FIG. 10) result in the same outcome. Similarly, when the WTRU is scheduled with a single repetition for each TB, both embodiments (circulating for each TB and then for each repetition in FIG. 9, and circulating for each repetition first and then for each TB in FIG. 10) result in the same outcome. In this case, the WTRU may transmit a set of TBs using sub-slot multi-TTI scheduling. This may enable the transmission of n TBs in m slots, where m < n.

[0167] In one embodiment, the WTRU may transmit a single TB per slot. In such a case, the nominal repetition of the TB may be mapped to non-adjacent slots. For example, each TB may be configured or associated with a slot offset and periodicity. The slot periodicity may be fixed for some or all of the TBs. For example, the first TB may be mapped to a slot with offset 0 and periodicity 3, the second TB may be mapped to a slot with offset 1 and periodicity 3, and the third TB may be mapped to a slot with offset 2 and periodicity 3. In such an example, if each TB has three repetitions, the first TB may have its repetitions mapped to slots 1, 4, 7, the second TB may have its repetitions mapped to slots 2, 5, 8, and the third TB may have its repetitions mapped to slots 3, 6, 9. In each slot, the TB may have multiple nominal or actual repetitions.

[0168] The WTRU may be composed of a table having elements indicating the number of repetitions, slot offset, slot periodicity, and number of TBs. The scheduling DCI may provide an index pointing to a set of parameters found in the table.

[0169] Figure 11 shows an example of a cycle with a single TB per slot. In this example, TB1 has three repetitions of three symbols each, TB2 has three repetitions of four symbols each, and TB3 has five repetitions of two symbols each. In some examples, all TBs scheduled with multi-TTI scheduling may have the same number of repetitions and the same number of symbols per repetition. In Figure 11, TB1 is transmitted in slots 1 and 4, TB2 is transmitted in slots 2 and 5, and TB3 is transmitted in slots 3 and 6. The nominal repetitions of a TB may be split or segmented and may span multiple non-adjacent slots. For example, the second nominal repetition of TB2 in this example is split, with the first actual repetition being transmitted in the second slot and the second actual repetition being transmitted in the fifth slot.

[0170] The WTRU may determine the repetition element according to the number of repetitions within a slot or the number of different TBs. For example, the WTRU may transmit a single DM-RS within a slot if all repetitions within the slot are for the same TB.

[0171] The WTRU may be configured or enabled to transmit multiple TBs, and each TB may have multiple repetitions. The WTRU may receive an indication of a first HARQ process ID and may determine a subsequent HARQ process ID for subsequent TBs according to the cycle / mapping type. For example, the HARQ process ID may be incremented per slot, or per repetition, or per set of repetitions. The increment method and step size may be configurable, fixed, or dynamically indicated.

[0172] For configured grant transmission, the WTRU may indicate the HARQ process ID in the CG-UCI. The HARQ process ID indication may be provided in all CG-UCI or in a subset of CG-UCI transmissions. The increment method may be fixed or indicated by the WTRU in at least one CG-UCI.

[0173] In one embodiment, the WTRU may be allocated or configured with resources for transmitting repetitions of the TB over multiple slots. For example, the WTRU may have a nominal repetition with a duration longer than the slot duration. In such a case, the WTRU may segment the repetition and transmit different parts of the TB in different actual repetitions. For example, the nominal repetition may be segmented into multiple actual repetitions, and the TB may be segmented such that a portion of the TB is transmitted in each actual repetition associated with the nominal repetition.

[0174] In one embodiment, the WTRU can map each actual repetition to a single slot. The TDRA for each actual repetition within the nominal repetition may be fixed such that the same time resources are used in all slots of the nominal repetition.

[0175] The WTRU may receive a HARQ-ACK for at least one TB of a set of TBs scheduled via multi-TTI scheduling. Upon receiving an ACK for a TB, the WTRU may not need to continue transmitting the repetition for that TB. In some embodiments, not transmitting the repetition for a single TB may lead to a transmission gap that may lead to the need to perform LBT before other repetitions.

[0176] The WTRU may reuse the resources originally allocated to the first TB (e.g., upon receiving an ACK) for the repeated transmission of the second TB. The second TB may be a TB for which the WTRU has already transmitted some repetitions. The second TB may be a new TB for which the WTRU has not yet transmitted any repetitions.

[0177] In one embodiment, the WTRU can shift the remaining repetitions and TBs in order to use the resources originally allocated to the acknowledged transport block (TB).

[0178] In one embodiment, the WTRU may be allocated resources for the repetition of a hybrid automatic repeat request (HARQ) process (e.g., not for a specific TB). The WTRU may receive an indication to use the HARQ process for which an ACK has been received to transmit a new TB. The indication may be received by the WTRU in the same message by which it receives the ACK (e.g., a control resource set downlink format indicator (CG-DFI)). The indication may be received in a new downlink control information (DCI). The indication may be received via radio resource control (RRC) signaling. The new TB may be transmitted using the repetition resources associated with the HARQ process. Different HARQ processes may have different numbers of repetitions. The WTRU may include an indication of the number of repetitions in the repetition element (e.g., a control grant uplink control information (CG-UCI)).

[0179] In one embodiment, the WTRU may remap the remaining repetitions in order to take into account newly available uplink resources that were originally mapped to the acknowledged TB. Such remapping may be indicated to the WTRU or may be autonomously determined by the WTRU. Prior to remapping the remaining TBs, the WTRU may acknowledge the remapping to the gNB. In one embodiment, the WTRU may be triggered to transmit at least one element (e.g., a CG-UCI or UCI) in the remapped repetitions.

[0180] The WTRU can cycle through different TBs in a multi-TTI grant. Each TB can be mapped to a different slot, and each slot can be associated with a different HARQ process. In a given slot, the WTRU may include one or more repetitions for the associated HARQ process. The WTRU may or may not complete the required number of repetitions in that slot. If the WTRU does not complete the required number of repetitions, the WTRU may complete the remaining repetition transmissions on a subsequent scheduled multi-TTI grant (or other grant).

[0181] For a given multi-TTI grant, the WTRU may perform transmissions on all TTIs following a single LBT for any of the TTIs. If the LBT fails for a given TTI, the WTRU may attempt another LBT procedure for the next TTI. For a TB transmission attempt that fails on a given TTI due to LBT, the WTRU may cycle to the next TB / HARQ process. The WTRU may skip or defer failed repetition transmissions due to LBT and act as if they were transmitted.

[0182] If the HARQ process for the next TTI of the WTRU does not include the TB that is pending (e.g., no other / previously pending TB was transmitted on the HARQ process associated with the slot), and / or if the TB that failed LBT was not previously transmitted on a different HARQ process, the TB transmission that failed due to LBT can be mapped to the next TTI within the grant or a different TTI. The different TTI can be the first TTI available in the grant after the WTRU has finished cycling through the TB. For example, the WTRU can add the TB repetition last (e.g., at the end of the grant) after cycling through the other HARQ processes. The WTRU can multiplex the HARQ processes associated with the dropped TB / repetition parts of the UCI multiplexed on the PUSCH transmission. This can depend on or be based on whether the selected TTI on which the TB / repetition is transmitted is associated with a different HARQ process than the HARQ process used to initially transmit the TB.

[0183] If multiple repetitions of a TB are to be transmitted before cycling to another TB, the WTRU may skip the repetitions for which the LBT has failed. If all TBs are cycled first, the WTRU may delay TB transmission until the next PUSCH opportunity for which the LBT is successful. The WTRU may shift the transmission sequence by an offset when the LBT fails in order to transmit a given repetition on a multi-TTI grant. The offset may be configured (e.g., by a higher layer, RRC, or DCI) or may be pre-determined as the number of repetitions per TB. In an exemplary transmission (x.y), x may be the number of TBs and y may be the number of repetitions. Assuming there are 4 TBs each repeated 2 times, the WTRU may transmit the TB repetitions of "1.1 1.2 2.1 2.2 3.1 3.2 4.1 4.2" using the first cycling method. In the second cycling method, the WTRU may transmit the TB repetitions of "1.1 2.1 3.1 4.1 1.2 2.2 3.2 4.2". If the WTRU uses the second cycling method and the LBT fails for 1.1, the WTRU may skip the transmission of 2.1 because the WTRU may not transmit anything for the first TB until the fourth opportunity. If the LBT fails for transmitting a repetition, the WTRU may shift the entire TB transmission sequence by an offset.

[0184] The WTRU may be configured with a common SLIV / K for all TBs within a multi-slot transmission. Alternatively, the SLIV / K may be set individually for each TB. Whether a common or TB-specific repetition configuration is used may depend on, for example, the number of TBs scheduled by the grant, the traffic characteristics of the TBs (e.g., URLLC or eMBB), the signaling method (or associated overhead) used to indicate the repetition parameters (e.g., via an RRC table or DCI), or the channel characteristics (e.g., Reference Signal Received Power (RSRP)).

[0185] The repetition parameters for each TB may depend on one or more of, for example, the characteristics of the TB (e.g., TB length or QoS requirements), the resources scheduled for TB transmission (e.g., the position of the TB start / end within a slot), the relative positions of consecutive TBs (e.g., in a TDD scenario, if two TBs are scheduled in close temporal proximity, the first TB may be restricted in the possible number of repetitions), the slot format of the slot in which a particular TB is transmitted, or the channel characteristics (e.g., RSRP, channel occupancy).

[0186] The WTRU may select the SLIV / K common to all TBs or specific to each TB within a multi-slot grant via an explicit indication in the scheduling DCI. The repetition characteristics may be indicated via an existing DCI format with one or more reused spare bits, via an extended DCI field, or via a new DCI. If only one configuration exists, or if there is no field used to indicate TB-specific repetition parameters, the WTRU may interpret the repetition parameters as common to all TBs scheduled via the DCI.

[0187] The repetition parameters may be configured semi-statically (e.g., via RRC signaling) and stored in a table. The table may be configured individually, and the multi-slot scheduling DCI may indicate the repetition parameters to be used for the TBs within the grant via a pointer to a specific SLIV / K. The table (e.g., an RRC table) may be used to indicate resources for multi-TB transmission and may indicate the repetition format / parameters for each TB.

[0188] The features and elements are described above in a particular combination, but one of ordinary skill in the art will understand that each feature or element can be used alone or in any combination with other features and elements. Additionally, the methods described herein can 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 via wired or wireless connections) and computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, magnetic media such as read only memory (ROM), random access memory (RAM), registers, cache memory, semiconductor memory devices, internal hard disks, and removable disks, magneto-optical media, and optical media such as CD-ROM disks and digital versatile disks (DVD). A radio frequency transceiver for use in a WTRU, UE, terminal, base station, RNC, or any host computer can be implemented using a processor associated with the software.

Claims

1. 1. A wireless transmit / receive unit (WTRU), comprising: A transceiver; a processor; The transceiver and the processor are configured to receive information for transmitting uplink data, the information indicating a first number of nominal repetitions and a first number of symbols for each of the first number of nominal repetitions; The processor is further configured to determine a set of symbols associated with a first nominal iteration; The transceiver and the processor are further configured to transmit a second number of actual repetitions in symbols associated with the first nominal repetition, and the second number of actual repetitions and the symbols used to transmit the second number of actual repetitions are based on the occurrence of an event in the set of symbols associated with the first nominal repetition.

2. 10. The WTRU of claim 1, wherein the event is at least one of a channel occupation time (COT) end, a channel access resource, a channel access procedure result, a fixed frame period (FFP) idle period start time, or an FFP idle period end time.

3. The WTRU of claim 1 , wherein the set of symbols associated with the first nominal repetition comprises one or more subsets of consecutive uplink symbols.

4. 4. The WTRU of claim 3, wherein each of the one or more subsets of consecutive uplink symbols comprises at least two symbols, and wherein one subset of the one or more subsets of consecutive uplink symbols does not overlap with another subset of the one or more subsets of consecutive uplink symbols.

5. The transceiver and the processor, on the condition that the event occurs during the set of symbols associated with the first nominal repetition, 5. The WTRU of claim 4, further configured to: transmit a first actual repetition in one or more uplink symbols of the one or more subsets of consecutive uplink symbols prior to occurrence of the event; and transmit a second actual repetition after the first actual repetition in one or more uplink symbols of the one or more subsets of consecutive uplink symbols after occurrence of the event, provided that a channel access procedure is successful.

6. The WTRU of claim 5, wherein the first actual repetition is not transmitted in any symbols after the event.

7. The WTRU of claim 5 , wherein the channel access procedure is a Listen-Before-Talk (LBT) procedure.

8. 6. The WTRU of claim 5, wherein the channel access procedure is based on at least one of a channel occupancy time (COT) timing, an initiator of the COT, a fixed frame period (FFP) timing, a previous channel access procedure result, whether a gap precedes a repetition, a size of the gap between repetitions, or a cause of the gap between repetitions.

9. 2. The WTRU of claim 1, wherein an actual repetition of the second number of actual repetitions comprises at least one of a configured grant uplink control information (CG-UCI), a demodulation reference signal (DM-RS), a scheduling request (SR), a channel state information (CSI), a hybrid automatic repeat request (HARQ) acknowledgement (ACK), or a transport block (TB).

10. 6. The WTRU of claim 5, wherein the transceiver and the processor are further configured to receive configuration information regarding resources for performing the channel access procedure, the resources including at least one of a set of time instances, a set of frequency domains, or a beam.

11. 1. A method implemented by a wireless transmit / receive unit (WTRU), the method comprising: receiving information for transmitting uplink data, the information indicating a first number of nominal repetitions and a first number of symbols for each of the first number of nominal repetitions; determining a set of symbols associated with a first nominal iteration; transmitting a second number of actual repetitions in a symbol associated with the first nominal repetition, the second number of actual repetitions and the symbol used to transmit the second number of actual repetitions being based on the occurrence of an event in the set of symbols associated with the first nominal repetition; A method comprising:

12. 12. The method of claim 11, wherein the event is at least one of a channel occupation time (COT) end, a channel access resource, a channel access procedure result, a fixed frame period (FFP) idle period start time, or an FFP idle period end time.

13. The method of claim 11 , wherein the set of symbols associated with the first nominal repetition comprises one or more subsets of consecutive uplink symbols.

14. 14. The method of claim 13, wherein each of the one or more subsets of consecutive uplink symbols comprises at least two symbols, and wherein one subset of the one or more subsets of consecutive uplink symbols does not overlap with another subset of the one or more subsets of consecutive uplink symbols.

15. provided that the event occurs during the set of symbols associated with the first nominal iteration; transmitting a first actual repetition in one or more uplink symbols of the one or more subsets of consecutive uplink symbols prior to an occurrence of the event; transmitting, on condition that a channel access procedure is successful, a second actual repetition after the first actual repetition transmission in one or more uplink symbols of the one or more subsets of consecutive uplink symbols after the occurrence of the event; The method of claim 14 further comprising:

16. The method of claim 15 , wherein the first actual repetition is not transmitted in any symbols after the event.

17. The method of claim 15, wherein the channel access procedure is a Listen Before Talk (LBT) procedure.

18. 16. The method of claim 15, wherein the channel access procedure is based on at least one of a channel occupancy time (COT) timing, an initiator of the COT, a fixed frame period (FFP) timing, a previous channel access procedure result, whether a repetition is preceded by a gap, a size of the gap between the repetitions, or a cause of the gap between the repetitions.

19. 12. The method of claim 11, wherein an actual repetition of the second number of actual repetitions comprises at least one of a configured grant uplink control information (CG-UCI), a demodulation reference signal (DM-RS), a scheduling request (SR), a channel state information (CSI), a hybrid automatic repeat request (HARQ) acknowledgement (ACK), or a transport block (TB).

20. 16. The method of claim 15, further comprising: receiving configuration information regarding resources for performing the channel access procedure, the resources comprising at least one of a set of time instances, a set of frequency domains, or a beam.

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