CN117441306A - Method and device for performing PUSCH repetition - Google Patents

Abstract

A method and apparatus for performing a channel access procedure and transmitting a set of repetitions is disclosed. 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 the first scalar complex and transmit a second number of actual repetitions in the symbols associated with the first scalar complex. The second number of actual repetitions and the symbol for transmitting the second number of actual repetitions may be based on events occurring during a group of symbols associated with the first scalar complex. The set of symbols associated with the first scalar complex may include one or more subgroups of contiguous uplink symbols.

Description

Method and device for performing PUSCH repetition

Cross Reference to Related Applications

The present application claims the benefit of U.S. provisional application No. 63/167,953, filed on 3 months of 2021, and U.S. provisional application No. 63/185,576, filed on 7 months of 2021, the contents of which are incorporated herein by reference.

Background

Different types of Physical Uplink Shared Channel (PUSCH) repetition are defined. The repetition type a enables a single repetition in each slot. The enhanced repetition type a for the 5G new radio (NR-U) of the unlicensed spectrum enables multiple repetitions in each slot, but the mapping on all slots is fixed. Repetition type B enables sub-slot repetition to be achieved by using nominal repetition. multi-TTI scheduling has advantages such as reduced amount of scheduling signaling. Furthermore, if each PUSCH maps to a full slot, multi-TTI scheduling can reduce the need for Listen Before Talk (LBT) before each transmission. There is a need for methods and apparatus for implementing sub-slot repetition and implementing multi-TTI scheduling with repetition in an unlicensed environment.

Disclosure of Invention

A wireless transmit/receive unit (WTRU) may be configured to receive information to transmit uplink data. Uplink data may be transmitted through the PUSCH. 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 the first scalar complex. The WTRU may be configured to transmit a second number of actual repetitions in a symbol associated with the first scalar complex. The second number of actual repetitions and the symbol for transmitting the second number of actual repetitions may be based on events occurring during a group of symbols associated with the first scalar complex. The event may be at least one of: channel Occupancy Time (COT) end, channel access resources, channel access procedure result, fixed Frame Period (FFP) idle period start time, or FFP idle period end time. The set of symbols associated with the first scalar complex may include one or more subgroups of contiguous uplink symbols. At least one of the one or more sub-set of consecutive uplink symbols may comprise at least two symbols. One of the one or more sub-sets of consecutive uplink symbols may not overlap with another of the one or more sub-sets of consecutive uplink symbols. The WTRU may be configured to transmit a first actual repetition in one or more of the one or more subsets of consecutive uplink symbols before the event occurs, and to transmit a second actual repetition after the first actual repetition in one or more of the one or more subsets of consecutive uplink symbols after the event occurs, if the channel access procedure is successful, if the event occurs during a set of symbols associated with the first scalar complex. After the event, the first actual repetition may not be transmitted in the symbol. 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, the originator of the COT, fixed Frame Period (FFP) timing, previous channel access procedure results, whether there is a gap before repetition, the size of the gap between repetitions, or the reason for generating the gap between repetitions. The actual repetition of the second number of actual repetitions may include at least one of: configuration grants 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 used to perform a channel access procedure. The resource may include at least one of: a set of time instances, a set of frequency ranges, or beams.

The WTRU may be configured to determine when to perform a channel access procedure. The determination of when to perform the channel access procedure may be based on at least one of: repetition number, size of gap between repetitions, reason for generating gap between repetitions, frequency hopping, beam change, channel Occupancy Time (COT) timing, whether COT is user initiated or network initiated, fixed Frame Period (FFP) timing, or previous channel access procedure results. 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 about the channel access type used to resume the transmission. The WTRU may be configured to receive a semi-static configuration for recovering the transmitted channel access type. An indication of a set of invalid resources in Downlink Control Information (DCI) may be received. The WTRU may be configured to receive configuration information regarding resources used to perform LBT. The resource may include at least one of: a set of time instances, a set of frequency ranges, or beams. The repetition may be associated with a set of potential start times. The WTRU may be configured to determine that the channel is idle and transmit a repetition 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 transmission repetition. The WTRU may be configured to receive configuration information indicating a set of nominal repetitions, determine a set of symbols on which the nominal repetitions may occur, and determine whether the set of symbols on which the nominal repetitions may occur are valid. Whether the set of symbols on which nominal repetition may occur is valid may be determined based on at least one of: whether LBT, COT boundary timing, FFP idle period timing, or previous LBT results need to be performed before repetition. The WTRU may be configured to segment the nominal repetition on the condition that the nominal repetition includes one or more invalid symbols in the nominal repetition. The WTRU may be configured to determine the type of LBT to use before repeating. The type of LBT to be used may be determined based on at least one of: the COT timing, COT indicator, COT status, gap size, reason for generating the gap, or whether a different TB than the previous repeat transmission is transmitted. The repeated transmissions may include at least one of: CG-UCI, DM-RS, UCI or TB. The WTRU may be configured to skip, cancel, or defer repetition if LBT fails. The WTRU may be configured to receive configuration information indicating resources on which to transmit a plurality of transport blocks. The WTRU may be configured to transmit all repetitions of one TB and then transmit the repetition of another TB. The WTRU may be configured to transmit all first repetitions of all TBs, and then transmit second repetitions of the TBs. The WTRU may be configured to receive configuration information regarding LBT bandwidth hopping pattern information. The WTRU may be configured to perform frequency hopping between transmissions of the respective repetitions.

Drawings

A more detailed understanding of the description may be derived from the following description, taken in conjunction with the accompanying drawings, wherein like reference numerals refer to like elements, and in which:

FIG. 1A is a system diagram illustrating an exemplary communication system in which one or more disclosed embodiments may be implemented;

fig. 1B is a system diagram illustrating an exemplary wireless transmit/receive unit (WTRU) that may be used within the communication system shown in fig. 1A according to one embodiment;

fig. 1C is a system diagram illustrating an exemplary Radio Access Network (RAN) and an exemplary Core Network (CN) that may be used within the communication system shown in fig. 1A according to one embodiment;

fig. 1D is a system diagram illustrating another exemplary RAN and another exemplary CN that may be used in the communication system shown in fig. 1A according to one embodiment;

FIG. 2 shows an example of repetition type A;

FIG. 3 shows an example of repetition type B;

FIG. 4 shows an example of a modified repetition type A;

fig. 5 shows an example of multi-TTI scheduling;

FIG. 6 shows an example of COT ending in the middle of a repetition;

FIG. 7 shows an example of mapping a nominal repetition to an actual repetition;

FIG. 8 shows an example of an isolated symbol;

Fig. 9 illustrates an exemplary mapping of repetitions using multi-TTI scheduling;

fig. 10 illustrates an exemplary mapping of repetitions using multi-TTI scheduling; and is also provided with

Fig. 11 shows an exemplary repetition cycle with a single transport block per slot.

Detailed Description

Fig. 1A is a schematic diagram illustrating an exemplary communication system 100 in which one or more disclosed embodiments may be implemented. Communication system 100 may be a multiple-access system that provides content, such as voice, data, video, messages, broadcasts, etc., to a plurality of wireless users. Communication system 100 may enable multiple wireless users to access such content through the sharing of system resources, including wireless bandwidth. For example, communication system 100 may employ one or more channel access methods, such as Code Division Multiple Access (CDMA), time Division Multiple Access (TDMA), frequency Division Multiple Access (FDMA), orthogonal FDMA (OFDMA), single carrier FDMA (SC-FDMA), zero-tail unique word discrete fourier transform spread OFDM (ZT-UW-DFT-S-OFDM), unique word OFDM (UW-OFDM), resource block filter OFDM, filter Bank Multicarrier (FBMC), and the like.

As shown in fig. 1A, the communication system 100 may 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 should be understood that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and/or network elements. Each of the WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and/or communicate in a wireless environment. For example, the WTRUs 102a, 102b, 102c, 102d, any of which may be referred to as a Station (STA), may be configured to transmit and/or receive wireless signals, and may include User Equipment (UE), mobile stations, fixed or mobile subscriber units, subscription-based units, pagers, cellular telephones, personal Digital Assistants (PDAs), smartphones, laptop computers, netbooks, personal computers, wireless sensors, hot spot or Mi-Fi devices, internet of things (IoT) devices, watches or other wearable devices, head Mounted Displays (HMDs), vehicles, drones, medical devices and applications (e.g., tele-surgery), industrial devices and applications (e.g., robots and/or other wireless devices operating in an industrial and/or automated processing chain environment), consumer electronic devices, devices operating on a commercial and/or industrial wireless network, and the like. Any of the WTRUs 102a, 102b, 102c, and 102d may be interchangeably referred to as a UE.

Communication system 100 may also include base station 114a and/or base station 114b. Each of the base stations 114a, 114b may be any type of device configured to wirelessly interface with at least one of the WTRUs 102a, 102b, 102c, 102d to facilitate access to one or more communication networks, such as the CN 106, the internet 110, and/or the other networks 112. As an example, the base stations 114a, 114B may be Base Transceiver Stations (BTSs), node bs, evolved node bs (enbs), home node bs, home evolved node bs, next generation node bs, such as a gnnode B (gNB), new air interface (NR) node bs, site controllers, access Points (APs), wireless routers, and the like. Although the base stations 114a, 114b are each depicted as a single element, it should be appreciated that the base stations 114a, 114b may include any number of interconnected base stations and/or network elements.

Base station 114a may be part of RAN 104 that may also include other base stations and/or network elements (not shown), such as Base Station Controllers (BSCs), radio Network Controllers (RNCs), relay nodes, and the like. Base station 114a and/or base station 114b may be configured to transmit and/or receive wireless signals on one or more carrier frequencies, which may be referred to as a cell (not shown). These frequencies may be in a licensed spectrum, an unlicensed spectrum, or a combination of licensed and unlicensed spectrum. A cell may provide coverage of wireless services to a particular geographic area, which may be relatively fixed or may change over time. The cell may be further divided into cell sectors. For example, a cell associated with base station 114a may be divided into three sectors. Thus, in an embodiment, the base station 114a may include three transceivers, i.e., one for each sector of a cell. In an embodiment, the base station 114a may employ multiple-input multiple-output (MIMO) technology and may utilize multiple transceivers for each sector of a cell. For example, beamforming may be used to transmit and/or receive signals in a desired spatial direction.

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

More specifically, as noted above, communication system 100 may be a multiple access system and may employ one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, or the like. For example, the base station 114a and WTRUs 102a, 102b, 102c in the RAN 104 may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) terrestrial radio access (UTRA), which may use Wideband CDMA (WCDMA) to establish the air interface 116.WCDMA may include communication protocols such as High Speed Packet Access (HSPA) and/or evolved HSPA (hspa+). HSPA may include high speed Downlink (DL) packet access (HSDPA) and/or high speed Uplink (UL) packet access (HSUPA).

In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as evolved UMTS terrestrial radio access (E-UTRA), which may use Long Term Evolution (LTE) and/or LTE-advanced (LTE-a) and/or LTE-advanced Pro (LTE-a Pro) to establish the air interface 116.

In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as NR radio access, which may use NR to establish the air interface 116.

In embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement multiple radio access technologies. For example, the base station 114a and the WTRUs 102a, 102b, 102c may implement LTE radio access and NR radio access together, e.g., using a Dual Connectivity (DC) principle. Thus, the air interface utilized by the WTRUs 102a, 102b, 102c may be characterized by multiple types of radio access technologies and/or transmissions sent to/from multiple types of base stations (e.g., enbs and gnbs).

In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement radio technologies such as IEEE 802.11 (i.e., wireless fidelity (WiFi)), IEEE 802.16 (i.e., worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000 1X, CDMA EV-DO, tentative standard 2000 (IS-2000), tentative standard 95 (IS-95), tentative standard 856 (IS-856), global system for mobile communications (GSM), enhanced data rates for GSM evolution (EDGE), GSM EDGE (GERAN), and the like.

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

The RAN 104 may communicate with a CN 106, which may be any type of network configured to provide voice, data, application, and/or voice over internet protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102 d. The data may have different quality of service (QoS) requirements, such as different throughput requirements, delay requirements, error tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, and the like. The CN 106 may provide call control, billing services, mobile location based services, prepaid calls, internet connections, video distribution, etc., and/or perform advanced security functions such as user authentication. Although not shown in fig. 1A, it should be appreciated that RAN 104 and/or CN 106 may communicate directly or indirectly with other RANs that employ the same RAT as RAN 104 or a different RAT. For example, in addition to being connected to the RAN 104 that may utilize NR radio technology, the CN 106 may also communicate with another RAN (not shown) that employs GSM, UMTS, CDMA 2000, wiMAX, E-UTRA, or WiFi radio technology.

The CN 106 may also act as a gateway for the WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the internet 110, and/or other networks 112.PSTN 108 may include circuit-switched telephone networks that provide Plain Old Telephone Services (POTS). The internet 110 may include a global system for interconnecting computer networks and devices using common communication protocols, such as Transmission Control Protocol (TCP), user Datagram Protocol (UDP), and/or Internet Protocol (IP) in the TCP/IP internet protocol suite. Network 112 may include wired and/or wireless communication networks owned and/or operated by other service providers. For example, the network 112 may include another CN connected to one or more RANs, which may employ the same RAT as the RAN 104 or a different RAT.

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

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

The processor 118 may be a general purpose processor, a special purpose processor, a conventional processor, a Digital Signal Processor (DSP), a plurality of microprocessors, one or more microprocessors in association with a DSP core, a controller, a microcontroller, application Specific Integrated Circuits (ASICs), field Programmable Gate Arrays (FPGAs), any other type of Integrated Circuit (IC), a state machine, or the like. The processor 118 may perform signal coding, data processing, power control, input/output processing, and/or any other functions that enable the WTRU 102 to operate in a wireless environment. The processor 118 may be coupled to a transceiver 120, which may be coupled to a transmit/receive element 122. Although fig. 1B depicts the processor 118 and the transceiver 120 as separate components, it should be understood that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip.

The transmit/receive element 122 may be configured to transmit signals to and receive signals from a base station (e.g., base station 114 a) over the air interface 116. For example, in one embodiment, the transmit/receive element 122 may be an antenna configured to transmit and/or receive RF signals. In one embodiment, the transmit/receive element 122 may be an emitter/detector configured to emit 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 RF and optical signals. It should be appreciated that the transmit/receive element 122 may be configured to transmit and/or receive any combination of wireless signals.

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

The transceiver 120 may be configured to modulate signals to be 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. For example, therefore, the transceiver 120 may include multiple transceivers to enable the WTRU 102 to communicate via multiple RATs (such as NR and IEEE 802.11).

The processor 118 of the WTRU 102 may be coupled to and may receive user input data from a speaker/microphone 124, a keypad 126, and/or a display/touchpad 128, such as a Liquid Crystal Display (LCD) display unit or an Organic Light Emitting Diode (OLED) display unit. The processor 118 may also output user data to the speaker/microphone 124, the keypad 126, and/or the display/touchpad 128. Further, 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. Removable memory 132 may include a Subscriber Identity Module (SIM) card, a memory stick, a Secure Digital (SD) memory card, and the like. In other embodiments, the processor 118 may never physically locate memory access information on the WTRU 102, such as on a server or home computer (not shown), and store the data in that memory.

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

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

The processor 118 may also be coupled to other peripheral devices 138, which may include one or more software modules and/or hardware modules that provide additional features, functionality, and/or wired or wireless connections. For example, the peripheral device 138 may include an accelerometer, an electricalSub-compasses, satellite transceivers, digital cameras (for photo and/or video), universal Serial Bus (USB) ports, vibrating devices, television transceivers, hands-free headsets, portable electronic devices, and portable electronic devices,Modules, frequency Modulation (FM) radio units, digital music players, media players, video game player modules, internet browsers, virtual reality and/or augmented reality (VR/AR) devices, activity trackers, and the like. The peripheral device 138 may include one or more sensors. The sensor may be one or more of the following: gyroscopes, accelerometers, hall effect sensors, magnetometers, orientation sensors, proximity sensors, temperature sensors, time sensors; geographic position sensors, altimeters, light sensors, touch sensors, magnetometers, barometers, gesture sensors, biometric sensors, humidity sensors, and the like.

WTRU 102 may include a full duplex radio for which transmission and reception of some or all signals (e.g., associated with a particular subframe for UL (e.g., for transmission) and DL (e.g., for reception)) may be concurrent and/or simultaneous. The full duplex radio station may include an interference management unit for reducing and/or substantially eliminating self-interference via hardware (e.g., choke) or via signal processing by a processor (e.g., a separate processor (not shown) or via processor 118). In an embodiment, the WTRU 102 may include a half-duplex radio for which some or all signals are transmitted and received (e.g., associated with a particular subframe for UL (e.g., for transmitting) or DL (e.g., for receiving).

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

RAN 104 may include enode bs 160a, 160B, 160c, but it should be understood that RAN 104 may include any number of enode bs while remaining consistent with an embodiment. The enode bs 160a, 160B, 160c may each include one or more transceivers to communicate with the WTRUs 102a, 102B, 102c over the air interface 116. In an embodiment, the evolved node bs 160a, 160B, 160c may implement MIMO technology. Thus, the enode B160 a may use multiple antennas to transmit wireless signals to the WTRU 102a and/or to receive wireless signals from the WTRU 102a, for example.

Each of the evolved node bs 160a, 160B, 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in UL and/or DL, and the like. As shown in fig. 1C, the enode bs 160a, 160B, 160C may communicate with each other over an X2 interface.

The CN 106 shown in fig. 1C may include a Mobility Management Entity (MME) 162, a Serving Gateway (SGW) 164, and a Packet Data Network (PDN) gateway (PGW) 166. Although the foregoing elements are depicted as part of the CN 106, it should be appreciated that any of these elements may be owned and/or operated by entities other than the CN operator.

The MME 162 may be connected to each of the evolved node bs 162a, 162B, 162c in the RAN 104 via an S1 interface and may function as a control node. For example, the MME 162 may be responsible for authenticating the user of the WTRUs 102a, 102b, 102c, bearer activation/deactivation, selecting a particular serving gateway during initial attach of the WTRUs 102a, 102b, 102c, and the like. MME 162 may provide control plane functionality for switching between RAN 104 and other RANs (not shown) employing other radio technologies such as GSM and/or WCDMA.

SGW 164 may be connected to each of the evolved node bs 160a, 160B, 160c in RAN 104 via an S1 interface. The SGW 164 may generally route and forward user data packets to/from the WTRUs 102a, 102b, 102 c. The SGW 164 may perform other functions such as anchoring user planes during inter-enode B handover, triggering paging when DL data is available to the WTRUs 102a, 102B, 102c, managing and storing the contexts of the WTRUs 102a, 102B, 102c, etc.

The SGW 164 may be connected to a PGW 166 that may provide the WTRUs 102a, 102b, 102c with access to a packet switched network, such as the internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices.

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

Although the WTRU is depicted in fig. 1A-1D as a wireless terminal, it is contemplated that in some representative embodiments such a terminal may use a wired communication interface with a communication network (e.g., temporarily or permanently).

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

A WLAN in an infrastructure Basic Service Set (BSS) mode may have an Access Point (AP) for the BSS and one or more Stations (STAs) associated with the AP. The AP may have access or interface to a Distribution System (DS) or another type of wired/wireless network that carries traffic to and/or from the BSS. Traffic originating outside the BSS and directed to the STA may arrive through the AP and may be delivered to the STA. Traffic originating from the STA and leading to a destination outside the BSS may be sent to the AP to be delivered to the respective destination. Traffic between STAs within the BSS may be sent through the AP, for example, where the source STA may send traffic to the AP and the AP may pass the traffic to the destination STA. Traffic between STAs within a BSS may be considered and/or referred to as point-to-point traffic. Point-to-point traffic may be sent between (e.g., directly between) the source and destination STAs using Direct Link Setup (DLS). In certain representative embodiments, the DLS may use 802.11e DLS or 802.11z Tunnel DLS (TDLS). A WLAN using an Independent BSS (IBSS) mode may not have an AP, and STAs (e.g., all STAs) within or using the IBSS may communicate directly with each other. The IBSS communication mode may sometimes be referred to herein as an "ad-hoc" communication mode.

When using the 802.11ac infrastructure mode of operation or similar modes of operation, the AP may transmit beacons on a fixed channel, such as a primary channel. The primary channel may be a fixed width (e.g., 20MHz wide bandwidth) or a dynamically set width. The primary channel may be an operating channel of the BSS and may be used by STAs to establish a connection with the AP. In certain representative embodiments, carrier sense multiple access/collision avoidance (CSMA/CA) may be implemented, for example, in an 802.11 system. For CSMA/CA, STAs (e.g., each STA), including the AP, may listen to the primary channel. If the primary channel is listened to/detected by a particular STA and/or determined to be busy, the particular STA may backoff. One STA (e.g., only one station) may transmit at any given time in a given BSS.

High Throughput (HT) STAs may communicate using 40MHz wide channels, for example, via a combination of a primary 20MHz channel with an adjacent or non-adjacent 20MHz channel to form a 40MHz wide channel.

Very High Throughput (VHT) STAs may support channels that are 20MHz, 40MHz, 80MHz, and/or 160MHz wide. 40MHz and/or 80MHz channels may be formed by combining consecutive 20MHz channels. The 160MHz channel may be formed by combining 8 consecutive 20MHz channels, or by combining two non-consecutive 80MHz channels (this may be referred to as an 80+80 configuration). For the 80+80 configuration, after channel coding, the data may pass through a segment parser that may split the data into two streams. An Inverse Fast Fourier Transform (IFFT) process and a time domain process may be performed on each stream separately. These streams may be mapped to two 80MHz channels and 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 sent to a Medium Access Control (MAC).

The 802.11af and 802.11ah support modes of operation below 1 GHz. Channel operating bandwidth and carrier are reduced in 802.11af and 802.11ah relative to those used in 802.11n and 802.11 ac. The 802.11af supports 5MHz, 10MHz, and 20MHz bandwidths in the television white space (TVWS) spectrum, and the 802.11ah supports 1MHz, 2MHz, 4MHz, 8MHz, and 16MHz bandwidths using non-TVWS spectrum. According to representative embodiments, 802.11ah may support meter type control/Machine Type Communication (MTC), such as MTC devices in macro coverage areas. MTC devices may have certain capabilities, such as limited capabilities, including supporting (e.g., supporting only) certain bandwidths and/or limited bandwidths. MTC devices may include batteries with battery lives above a threshold (e.g., to maintain very long battery lives).

WLAN systems that can support multiple channels, and channel bandwidths such as 802.11n, 802.11ac, 802.11af, and 802.11ah, include 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 may be set and/or limited by STAs from all STAs operating in the BSS (which support a minimum bandwidth mode of operation). In the example of 802.11ah, for STAs (e.g., MTC-type devices) that support (e.g., only) 1MHz mode, the primary channel may be 1MHz wide, even though the AP and other STAs in the BSS support 2MHz, 4MHz, 8MHz, 16MHz, and/or other channel bandwidth modes of operation. The carrier sense and/or Network Allocation Vector (NAV) settings may depend on the state of the primary channel. If the primary channel is busy, for example, because the STA is transmitting to the AP (only supporting 1MHz mode of operation), all available frequency bands may be considered busy even if most available frequency bands remain idle.

The available frequency band for 802.11ah in the united states is 902MHz to 928MHz. In korea, the available frequency band is 917.5MHz to 923.5MHz. In Japan, the available frequency band is 916.5MHz to 927.5MHz. The total bandwidth available for 802.11ah is 6MHz to 26MHz, depending on the country code.

Fig. 1D is a system diagram illustrating a RAN 104 and a CN 106 according to one embodiment. As noted above, the RAN 104 may employ NR radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. RAN 104 may also communicate with CN 106.

RAN 104 may include gnbs 180a, 180b, 180c, but it should be understood that RAN 104 may include any number of gnbs while remaining consistent with an embodiment. Each of the gnbs 180a, 180b, 180c may include one or more transceivers to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. In an embodiment, the gnbs 180a, 180b, 180c may implement MIMO technology. For example, gnbs 180a, 108b may utilize beamforming to transmit signals to and/or receive signals from gnbs 180a, 180b, 180 c. Thus, the gNB 180a may use multiple antennas to transmit wireless signals to the WTRU 102a and/or receive wireless signals from the WTRU 102a, for example. In an embodiment, the gnbs 180a, 180b, 180c may implement carrier aggregation techniques. For example, the gNB 180a may transmit multiple component carriers to the WTRU 102a (not shown). A subset of these component carriers may be on the unlicensed spectrum while the remaining component carriers may be on the licensed spectrum. In embodiments, the gnbs 180a, 180b, 180c may implement coordinated multipoint (CoMP) techniques. For example, WTRU 102a may receive coordinated transmissions from gNB 180a and gNB 180b (and/or gNB 180 c).

The WTRUs 102a, 102b, 102c may communicate with the gnbs 180a, 180b, 180c using transmissions associated with the scalable parameter sets. For example, the OFDM symbol interval and/or OFDM subcarrier interval may vary from one transmission to another, from one cell to another, and/or from one portion of the wireless transmission spectrum to another. The WTRUs 102a, 102b, 102c may communicate with the gnbs 180a, 180b, 180c using various or scalable length subframes or Transmission Time Intervals (TTIs) (e.g., including different numbers of OFDM symbols and/or continuously varying absolute time lengths).

The gnbs 180a, 180b, 180c may be configured to communicate with the WTRUs 102a, 102b, 102c in an independent configuration and/or in a non-independent configuration. In a standalone configuration, the WTRUs 102a, 102B, 102c may communicate with the gnbs 180a, 180B, 180c while also not accessing other RANs (e.g., such as the enode bs 160a, 160B, 160 c). In an independent configuration, the WTRUs 102a, 102b, 102c may use one or more of the gnbs 180a, 180b, 180c as mobility anchor points. In an independent configuration, the WTRUs 102a, 102b, 102c may use signals in unlicensed frequency bands to communicate with the gnbs 180a, 180b, 180 c. In a non-standalone configuration, the WTRUs 102a, 102B, 102c may communicate or connect with the gnbs 180a, 180B, 180c, while also communicating or connecting with other RANs (such as the enode bs 160a, 160B, 160 c). For example, the WTRUs 102a, 102B, 102c may implement DC principles to communicate with one or more gnbs 180a, 180B, 180c and one or more enodebs 160a, 160B, 160c substantially simultaneously. In a non-standalone configuration, the enode bs 160a, 160B, 160c may serve as mobility anchors for the WTRUs 102a, 102B, 102c, and the gnbs 180a, 180B, 180c may provide additional coverage and/or throughput for serving the WTRUs 102a, 102B, 102 c.

Each of the gnbs 180a, 180b, 180c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in UL and/or DL, support of network slices, interworking between DC, NR, and E-UTRA, routing of user plane data towards User Plane Functions (UPFs) 184a, 184b, routing of control plane information towards access and mobility management functions (AMFs) 182a, 182b, and so on. As shown in fig. 1D, gnbs 180a, 180b, 180c may communicate with each other through an Xn interface.

The CN 106 shown in fig. 1D may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one Session Management Function (SMF) 183a, 183b, and possibly a Data Network (DN) 185a, 185b. Although the foregoing elements are depicted as part of the CN 106, it should be appreciated that any of these elements may be owned and/or operated by entities other than the CN operator.

The AMFs 182a, 182b may be connected to one or more of the gnbs 180a, 180b, 180c in the RAN 104 via an N2 interface and may function as control nodes. For example, the AMFs 182a, 182b may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, support for network slices (e.g., handling of different Protocol Data Unit (PDU) sessions with different requirements), selection of a particular SMF 183a, 183b, management of registration areas, termination of non-access stratum (NAS) signaling, mobility management, etc. The AMFs 182a, 182b may use network slices to customize CN support for the WTRUs 102a, 102b, 102c based on the type of service used by the WTRUs 102a, 102b, 102 c. For example, different network slices may be established for different use cases, such as services relying on ultra high reliability low latency (URLLC) access, services relying on enhanced mobile broadband (eMBB) access, services for MTC access, and so on. The AMFs 182a, 182b may provide control plane functionality for switching between the RAN 104 and other RANs (not shown) employing other radio technologies, such as LTE, LTE-A, LTE-a Pro, and/or non-3 GPP access technologies, such as WiFi.

The SMFs 183a, 183b may be connected to AMFs 182a, 182b in the CN 106 via an N11 interface. The SMFs 183a, 183b may also be connected to UPFs 184a, 184b in the CN 106 via an N4 interface. SMFs 183a, 183b may select and control UPFs 184a, 184b and configure traffic routing through UPFs 184a, 184b. The SMFs 183a, 183b may perform other functions such as managing and assigning UE IP addresses, managing PDU sessions, controlling policy enforcement and QoS, providing DL data notifications, etc. The PDU session type may be IP-based, non-IP-based, ethernet-based, etc.

The UPFs 184a, 184b may be connected to one or more of the gnbs 180a, 180b, 180c in the RAN 104 via an N3 interface, which may provide the WTRUs 102a, 102b, 102c with access to a packet-switched network, such as the internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices. UPFs 184, 184b may perform other functions such as routing and forwarding packets, enforcing user plane policies, supporting multi-host PDU sessions, handling user plane QoS, buffering DL packets, providing mobility anchoring, and the like.

The CN 106 may facilitate communications with other networks. For example, the CN 106 may include or may communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that serves as an interface between the CN 106 and the PSTN 108. In addition, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired and/or wireless networks owned and/or operated by other service providers. In one embodiment, the WTRUs 102a, 102b, 102c may connect to the DNs 185a, 185b through the UPFs 184a, 184b via an N3 interface to the UPFs 184a, 184b and an N6 interface between the UPFs 184a, 184b and the local DNs 185a, 185b.

In view of fig. 1A-1D and the corresponding descriptions of fig. 1A-1D, one or more or all of the functions described herein with reference to one or more of the following may be performed by one or more emulation devices (not shown): the WTRUs 102a-d, base stations 114a-B, evolved node bs 160a-c, MME 162, SGW 164, PGW 166, gNB 180a-c, AMFs 182a-B, UPFs 184a-B, SMFs 183a-B, DN 185a-B, and/or any other devices described herein. The emulated device may be one or more devices configured to emulate one or more or all of the functions described herein. For example, the emulation device may be used to test other devices and/or analog network and/or WTRU functions.

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

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

The WTRU may determine the actual repetition mapping of the nominal repetition based on channel access procedure (e.g., listen Before Talk (LBT)) timing and Channel Occupancy Time (COT) or Fixed Frame Period (FFP) configuration/timing.

The WTRU may determine the content of PUSCH repetition and transmission parameters according to at least one of: the timing of repetition, the timing of associated LBT, the duration of PUSCH repetition, the location of adjacent PUSCH repetition, the timing of COT, the result of previous LBT, the timing of FFP idle period, the identity of the COT initiator, the previous discard of Transport Blocks (TBs), or the cancel indication.

The WTRU may trigger repeated transmissions of PUSCH until a hybrid automatic repeat request (HARQ) -ACK is received, a timer expires, or until a new TB may be transmitted.

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

Repetition may be used to improve reliability of the transmission without the overhead of HARQ-ACK feedback. For ultra-reliable low latency communication (URLLC), two types of repetition are defined: repeat type a and repeat type B.

Fig. 2 shows an example of the repetition type a. In fig. 2, there are a plurality of slots separated by slot boundaries. A transmission repetition (e.g., PUSCH Transport Block (TB)) may be transmitted once in each slot. Each time slot may contain only one repetition and the time domain of these repetitions is the same in those time slots. The Start and Length Indicator Values (SLIV) are the same for all slots.

Repetition type a may be a simple way of implementing repetition. However, for shorter allocations (i.e., sub-slot allocations), such repetition may not achieve optimal delay. Achieving sub-slot repetition may have beneficial effects. Fig. 3 shows an example of the repetition type B. In fig. 3, there are six symbols in each slot (which may be used for uplink or downlink as indicated by "U" or "D", respectively), and each slot is separated by a slot boundary. PUSCH transmissions may be repeated within a slot.

The nominal repetition may be defined by combining a specific Time Domain Resource Allocation (TDRA)/Transport Block Size (TBS). The WTRU may receive the Guan Biao repeat information. The WTRU may receive information indicating a number of nominal repetitions, and a number of symbols in the nominal repetition on which PUSCH transmissions may be repeated. For example, DL symbols or slot boundaries may disrupt nominal repetition. The nominal repetition may be split 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 may be more than K actual repetitions. For example, in fig. 3, k=4 and the nominal repetition is 4 symbols. For this case, there are 5 actual repetitions.

The repetition type a may be modified to achieve multiple repetitions within a slot. Fig. 4 shows a modification to repeat type a, where there are two repetitions within a slot. This may, for example, reduce the required number of LBTs that a set of iterations need to be performed. However, each slot has the same number of repetitions, and the positions of the repetitions are fixed within the slot.

multi-TTI scheduling may 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., TB 1 … … TB 6) are transmitted in time slots 1 through 6, respectively.

Repetition (e.g., PUSCH repetition) may be beneficial to improve the robustness of the unlicensed spectrum. Sub-slot repetition for unlicensed spectrum may have limitations such that each slot may have a similar resource mapping. However, this scheme does not handle dynamic TDD slot formats well and lacks flexibility for different PUSCH allocation sizes. Repetition type B may have an advantageous effect, however, it is not specified in consideration of unlicensed spectrum. Therefore, a method is needed to enable repetition type B in unlicensed spectrum to handle the effects of LBT, COT and FFP times.

multi-TTI scheduling may have an advantageous effect because it reduces the need for signaling. However, there is a need to implement a method of multi-TTI scheduling with repetition, which can achieve reduced signaling overhead and robust and low-delay transmission.

The WTRU may be configured to perform a set of repetitions (e.g., repetitions for the TB). The WTRU may use a channel access procedure (e.g., LBT) before at least one repetition. Channel access procedure or LBT is used interchangeably herein.

The WTRU may determine when to perform LBT based on the repetition number. In one example, the WTRU may 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, where n is configurable.

The WTRU may determine when to perform LBT based on the gap before repetition. For example, if two consecutive repetitions are transmitted in adjacent symbols, the WTRU may not perform LBT until the second repetition. If there is a gap between the two repetitions, the WTRU may perform LBT before the second repetition.

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

The WTRU may determine when to perform LBT based on the reason or purpose of generating the gap between consecutive repetitions. For example, the WTRU may perform LBT before the second repetition based on the reason for the gap between the first and second consecutive repetitions. The reasons for generating the gap may include, for example, at least one of: DL symbols, flexible symbols for dynamic or semi-static handover to DL, orphan UL symbols, idle periods for Fixed Frame Periods (FFP), transmission cancelled (e.g., due to indication via UL CI), COT parameters changed, or transmission discarded due to LBT failure.

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

The WTRU may determine when to perform LBT based on the beam change. For example, if the transmit beam changes between consecutive repetitions, the WTRU may perform LBT before the first repetition occurs after the beam changes.

The WTRU may determine when to perform LBT based on the COT timing. For example, if consecutive repetitions are to be transmitted in different COTs, the WTRU may perform LBT before the second repetition and may initiate a new COT. In one example, if the repeated resources overlap with the end of the COT, the WTRU may perform LBT before transmitting the repetition and may initiate a new COT.

The WTRU may determine when to perform LBT based on who initiated the COT. For example, if the repetition is transmitted in a WTRU-initiated COT, the WTRU may determine a first set of LBT occasions. The WTRU may determine a second set of LBT occasions if the repetition is transmitted in the COT initiated by the gNB.

The WTRU may determine when to perform LBT based on the FFP timing. For example, if consecutive repetitions are to be transmitted in different FFPs, the WTRU may perform LBT before the second repetition.

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

The WTRU may receive an indication that resources (e.g., time or frequency units or beams) are not available to transmit the repetition. Such resources may be considered as invalid resources that are dynamically indicated. The indication may inform the WTRU of a set of invalid resources and the type of channel access required to resume transmission after such an invalid resource occurs. For example, the WTRU may receive an indication that the first resource is not available to transmit the repetition. Not performing a transmission on such resources may result in gaps (e.g., new gaps or already existing gap extensions) being created. The WTRU may determine the type of channel access (e.g., whether to use LBT, type of LBT, parameters associated with LBT) based on the indication. In one embodiment, the WTRU may be configured (e.g., semi-statically configured) or receive information about the behavior to be used for accessing the channel after such dynamically inactive resources are configured.

The WTRU may receive an indication of invalid resources or associated channel access in DCI (e.g., a set of repeated DCIs scheduled). The indication may explicitly indicate a set of resources on which to transmit duplicate invalidations. In one embodiment, the indication may be a bit field that maps to a pattern of a configurable set of invalid resources or channel access types.

The WTRU may be configured with or receive information of a set of resources (e.g., time instances or frequency ranges or beams) for when to perform LBT. When the WTRU is transmitting a set of repetitions, it may determine when any of a set of configured resources for performing LBT should be considered an invalid symbol for transmitting the repetition. The WTRU may perform LBT using one of the set of configured resources to obtain an unlicensed channel for transmitting one or more repetitions. For example, if such resources occur before an actual repetition or a nominal repetition (e.g., in an immediately preceding symbol), the WTRU may select resources from the set of configured resources to perform LBT. If, for example, there is no ongoing COT, the WTRU may perform LBT on one resource from a set of resources.

The WTRU may be configured with a set of nominal repetitions. The WTRU may determine a set of symbols on which each nominal repetition may occur.

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

The WTRU may determine whether a set of symbols for a nominal repetition is valid based on the COT boundary timing. For example, if the COT ends on one of the symbols in the repetition, the WTRU may not transmit on a set of n subsequent symbols in the repetition. In another example, if the COT ends in a symbol before the repetition, the WTRU may determine a set of m symbols that may not be used to transmit the repetition at the beginning of the subsequent repetition based on the time at which the COT ended.

The WTRU may determine whether a set of symbols for a nominal repetition is valid based on the FFP idle period timing. For example, if an FFP idle period occurs during repetition, symbols overlapping the idle period may not be used to transmit the repetition.

The WTRU may determine whether a nominally repeated set of symbols is valid based on previous LBT results. For example, based on the results of LBT for a previous repetition, the WTRU may determine a set of symbols that may be used to transmit a subsequent repetition.

The WTRU may split or segment the repetition into multiple actual repetitions when the nominal repetition has one or more invalid symbols that occur during the nominal repetition. Each actual repetition may be an entire transmission of the TB (e.g., using rate matching) or may be a segment of the TB. All segments of a TB may be transmitted in a set of actual repetitions including a nominal repetition.

Fig. 6 shows an example of the COT ending during repetition. After the end of the COT, the WTRU may use n symbols for LBT (where n=1 in fig. 6) to reinitiate the COT to continue the transmission repetition. For the repetition at which the COT ends (i.e., nominal repetition 3 in fig. 6), the WTRU may use two actual repetitions of the nominal repetition. In an embodiment, the WTRU may segment the repetition into two parts and transmit the first part in a first COT and the second part in a second COT.

The WTRU may split the nominal repetition into multiple actual repetitions based on the COT timing or the FFP idle period timing. The WTRU may segment the nominal repetition into a plurality of segments according to the COT timing or the idle period timing. For example, if the COT ends during the nominal repetition or an FFP idle period occurs during the repetition, the WTRU may split the nominal repetition and transmit two actual repetitions in two adjacent sets of uninterrupted resources (e.g., each actual repetition is transmitted by a copy of the TB). The two sets of adjacent resources may be separated by a COT boundary timing or an FFP idle period timing and may be separated by a resource for performing LBT prior to the second repetition.

FIG. 7 illustrates an exemplary method (700) of mapping a nominal repetition to an actual repetition. The WTRU may receive information (710) with a configuration of Guan Biao repetitions. The information may indicate a number of nominal repetitions. The information may indicate a number of symbols 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 a set of symbols associated with the nominal repetition based on at least one of: a start symbol of one nominal repetition (e.g., first nominal repetition), a total number of repetitions, a number of symbols per repetition, a repetition number (e.g., whether the nominal repetition is first nominal repetition or second nominal repetition or third nominal repetition, etc.), a received SLIV in a UL grant (e.g., in a DCI or RRC configuration), an SCS of the repetition, whether to use frequency hopping, a COT configuration, or a COT initiator (e.g., WTRU-initiated COT or gNB-initiated COT). The WTRU may transmit a plurality of actual repetitions (730). The number of actual repetitions may be greater than the number of nominal repetitions. The actual repetition may be transmitted in one or more symbols (e.g., consecutive symbols) associated with the target complex. The actual repeated transmission may be based on events occurring during a set of symbols associated with the target weight complex. The event may be, for example, the end of the COT, the channel access resource, the channel access procedure result, the FFP idle period start time, or the FFP idle period end time. The set of symbols associated with the target complex may include one or more subgroups of consecutive uplink symbols. A subset of consecutive uplink symbols may include at least two symbols. One subgroup of consecutive uplink symbols may not overlap with another subgroup of consecutive uplink symbols. The WTRU may transmit an actual repetition (e.g., a first actual repetition) in an uplink symbol in each subset of consecutive uplink symbols before the event occurs. The WTRU may perform a channel access procedure (e.g., LBT). If the channel access procedure is successful, the WTRU may transmit another actual repetition (e.g., a second actual repetition) after transmitting the first actual repetition in an uplink symbol in each of the sub-groups of consecutive uplink symbols after the event. If the channel access procedure fails. The WTRU may perform a second channel access procedure in the next symbol. If the second channel access procedure is successful, the WTRU may transmit another actual repetition after the first actual repetition in an uplink symbol in each of the sub-groups of consecutive uplink symbols after the event. If the second channel access procedure fails, the WTRU may continue to perform the channel access procedure until successful, and may then transmit the actual repetition.

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

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

The WTRU may use frequency hopping between repetitions. Frequency hopping may ensure that WTRUs have repetitions of scheduling for different LBT Bandwidths (BW) or channels, which may increase channel access probability. The WTRU may be configured with or receive configuration information for the LBT BW hopping pattern. Such a configuration may be a semi-static configuration or a dynamic configuration. For example, the WTRU may receive configuration information in DCI that schedules a set of repetitions.

The WTRU may determine a set of invalid symbols associated with frequency hopping. For example, an invalid symbol may affect the mapping of the first repetition transmitted after (e.g., immediately after) the frequency hopping. The WTRU may use such a set of invalid symbols to perform LBT in the new LBT BW.

The WTRU may perform LBT after frequency hopping. The WTRU may perform LBT after hopping if the hopping has moved the transmission to a frequency range in the new LBT BW (i.e., compared to the frequency range of the previous hopping).

The WTRU may perform LBT before a set of repetitions. Such LBT procedure may be applied to transmit a subsequent set of repetitions.

A WTRU performing LBT before a set of repetitions may perform LBT on at least one of: LBT BW covering the next repeated resource; or LBT BW covering all duplicate resources in a set of duplicates.

In one embodiment, the WTRU may perform LBT on a set of repeated LBT BW before transmitting the set of repetitions. The WTRU may not need to perform LBT every time it hops. In one embodiment, the WTRU may perform a first LBT of a first LBT type (e.g., LBT type 4, i.e., complete LBT) on a set of repeated LBT BW before transmitting the set of repetitions, and perform a second LBT of a second LBT type (e.g., LBT type 2, i.e., shorter LBT) on the transmitted LBT BW that occurs each time or only after frequency hopping.

The WTRU may be configured with multiple LBT types. Each LBT type may have different channel estimation parameters (e.g., energy detection threshold, contention window size, net channel estimation slot duration, etc.).

The WTRU may determine the type of LBT to use before transmitting the nominal repetition or the actual repetition by the COT timing. For example, if the COT has ended before the repeated timing or is to be ended during the repeated timing, the WTRU may perform a first type of LBT (e.g., LBT type 4) before the repetition. In one embodiment, the WTRU may determine the type or configuration of LBT based on the time the current COT was initiated (where 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 initiated prior to or during the transmission of a set of repetitions.

The WTRU may determine the type of LBT to use before transmitting a nominal repetition or an actual repetition by the COT initiator. For example, the WTRU may determine the type of LBT from the node that originally initiated the COT during which the repetition was transmitted.

The WTRU may determine the type of LBT to use before transmitting the nominal repetition or the actual repetition through the COT state. For example, if there is an ongoing COT, the WTRU may perform a first type or configuration of LBT (where a type may include not performing LBT), and if there is no ongoing COT and it is desired to initiate COT, the WTRU may perform a second type or configuration of LBT.

The WTRU may determine the type of LBT to use before transmitting the nominal repetition or the actual repetition by the gap size. For example, the WTRU may determine the type of LBT to use before transmitting a repetition based on the gap size between the repetition and the previous repetition.

The WTRU may determine the type of LBT to use before transmitting a nominal repetition or an actual repetition by the cause of the gap. For example, the WTRU may determine the type of LBT to use before transmitting a repetition based on the reason for the gap between the repetition and the previous repetition. Reasons for creating the gap may include: DL symbols, flexible symbols for dynamic or semi-static handover to DL, orphan UL symbols, idle periods for Fixed Frame Periods (FFP), transmission cancelled (e.g., due to indication via UL CI), COT parameters changed, or transmission discarded due to LBT failure.

By whether to transmit a TB that is different from a previous (e.g., immediately preceding) repeat transmission, the WTRU may determine the type of LBT to use before transmitting a nominal repeat or an actual repeat. For example, the WTRU may transmit multiple TBs. Each TB may have multiple repetitions. The WTRU may determine the LBT type if two consecutive repetitions are for the same or different TBs.

The WTRU may determine what to include in the repetition (i.e., the nominal repetition or the actual repetition). In repeated transmissions, the WTRU may include, for example, at least one of the following elements: CG-UCI, demodulation reference signals (DM-RS), UCI (e.g., scheduling Request (SR)), channel State Information (CSI), HARQ-ACK, or TB.

The WTRU may determine what to include in the repeated transmissions based on the repetition number. For example, the WTRU may include CG-UCI in (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.

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

The WTRU may determine what to include in the repeated transmissions based on whether the repetition has been split or segmented. For example, the WTRU may include CG-UCI or DM-RS or UCI once per nominal repetition. If the nominal repetition is split or segmented into multiple actual repetitions, the WTRU may transmit CG-UCI or DM-RS or UCI in a single actual repetition. The WTRU may determine that the actual repetition is to include CG-UCI or DM-RS or UCI as the y-th (e.g., first or last) repetition. The WTRU may determine that the actual repetition is to include CG-UCI or DM-RS or UCI as an actual repetition with a duration greater than the value x.

The WTRU may determine what to include in the repeated transmissions based on whether LBT was performed before (e.g., immediately before) the repetition. For example, if the WTRU performs an LBT procedure before repetition (e.g., after an immediately preceding repetition), the WTRU may include CG-UCI.

The WTRU may determine what to include in the retransmission based on the COT timing. For example, the WTRU may include CG-UCI in a repetition if a new COT has been initiated before the repetition is transmitted or in a time between the repetition and a previous repetition (e.g., an immediately previous repetition).

The WTRU may determine what to include in the repeated transmissions based on the repetition number within the time slot. For example, the WTRU may include CG-UCI or DM-RS or UCI in a single repetition within a slot. The WTRU may include CG-UCI or DM-RS or UCI in a first repetition of a slot.

The WTRU may determine what to include in the repeated transmissions based on the HARQ process ID. For example, the WTRU may include CG-UCI if the HARQ process ID of the TB has changed since a previous repeat transmission.

The WTRU may determine what content to include in the repeated transmissions based on the priority of the transmissions. For example, the WTRU may determine whether to include CG-UCI or UCI based on the priority of TB or UCI.

The WTRU may determine what to include in the repeated transmissions based on the previously discarded transmissions. For example, if CG-UCI in a previous repetition is discarded, it may be included in a subsequent repetition. In one example, the WTRU may include CG-UCI in a subsequent repeated transmission if the previous transmission was discarded (e.g., due to LBT failure to receive UL CI).

The WTRU may determine what to include in the repeated transmissions based on whether rate matching is used on the TB.

The WTRU may determine what to include in the repeated transmissions based on whether the frequency or beam has changed. For example, if the transmission repeats after frequency hopping or after a change in the transmit beam, the WTRU may include CG-UCI.

The WTRU may determine what elements to include in the repeated transmissions based on more than one transmission criteria as described herein. For example, if the TB has a high priority (e.g., greater than a threshold or configured value), the WTRU may determine that CG-UCI may be included in each repetition. In one example, the WTRU may include UCI in the first set of repetitions if the priority of UCI is high (e.g., greater than a threshold or a configured value), and may include UCI in the second set of repetitions if the priority of UCI is low (e.g., less than a threshold or a configured value).

The WTRU may discard an element in the repetition to include another element. For example, if the UCI has a high priority (e.g., greater than a threshold or configured value), the WTRU may discard the CG-UCI and transmit only UCI with the TB. When discarding an element to enable transmission of another (e.g., higher priority) element, the WTRU may include the discarded element in a subsequent repetition.

CG-UCI may be transmitted in multiple repetitions of a set of repetitions. The content of the CG-UCI may remain the same for each repetition. In one example, if CG-UCI is transferred in more than one repetition, the CG-UCI content in each CG-UCI transfer may change. For example, a first CG-UCI in a set of repetitions may include the required information (e.g., all required information), and any subsequent CG-UCI within the set of repetitions may include only the changes or updates that the CG-UCI has made. In one example, a first CG-UCI in a set of repetitions may include the required information (e.g., all of the required information), and subsequent CG-UCI may include only information related to the repetition. For example, if the HARQ process ID may change for each repetition, the CG-UCI may include the HARQ process ID related to the associated repetition, while any other content fixed for all repetitions may be transmitted by the WTRU only once in each set of repetitions.

The content of the CG-UCI may be determined by rules similar to those described herein to determine whether to include the CG-UCI. For example, the content of the CG-UCI may depend on the size of the actual repetition, and may incorporate the size of the nominal repetition.

The content of the CG-UCI may depend on whether it is multiplexed with other UCI. The content of CG-UCI multiplexed with other UCI may depend on the priority of CG-UCI or TB or the priority of other UCI.

The content of the CG-UCI may include at least one of: HARQ process ID, repetition number, priority (e.g., priority of transmission or priority of LBT used prior to transmission), redundancy Version (RV), modulation Coding Scheme (MCS), beam ID, nominal repetition duration, and DMRS mapping type.

An isolated symbol may occur when a nominal repetition is split or segmented into multiple potential actual repetitions and one such potential actual repetition is a single symbol. Splitting or segmentation may be caused by at least one of: DL symbols, slot boundaries, COT timing or FFP idle period timing.

The WTRU may transmit the repeated one or more elements using the isolated symbols. This may be beneficial in reducing the need for LBT due to the presence of unused isolated symbol gaps. In one example, the WTRU may transmit CG-UCI or DM-RS in isolated symbols. In such cases, the WTRU may not need to transmit the CG-UCI or DM-RS in one or more associated actual repetitions.

The WTRU may determine whether to transmit on or what elements to transmit in the orphan symbol based on the transmission criteria described herein.

The isolated symbol may be associated with an actual repetition based on whether both the isolated symbol and the actual repetition are in the same nominal repetition.

An isolated symbol may be associated with an actual repetition based on its timing. For example, an orphan symbol may be associated with a previous actual repetition. In another example, an orphan symbol may be associated with a subsequent actual repetition.

The orphan symbol may be associated with an actual repetition based on the duration of the actual repetition. For example, an orphan symbol may be associated with an actual repetition if its duration is less than the value x or greater than the value y.

The isolated symbols may be associated with actual repetitions based on slot timing. For example, if the orphan symbol and the actual transmission are in the same slot, the orphan symbol may be associated with the actual transmission.

The orphan symbol may be associated with an actual repetition based on the COT state. For example, the WTRU may determine to transmit on an orphan symbol if there is an ongoing COT or if there is no ongoing COT.

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

The WTRU may determine whether to transmit the element using the orphan symbol based on a gap that may occur if the orphan symbol is not used. For example, if not transmitting on an isolated symbol results in a gap between repetitions that is greater than a value x (e.g., a gap requiring LBT before the next repeated transmission), the WTRU may transmit one or more elements on the isolated symbol. The WTRU may determine whether to transmit using the isolated symbol based on whether the two isolated symbols are adjacent. For example, when two isolated symbols are adjacent, the WTRU may transmit on at least one of the isolated symbols.

Fig. 8 shows an example of two adjacent isolated symbols, both of which appear in nominal repetition 2. In this case, the WTRU may determine that the gap generated by one or more neighboring orphan symbols is greater than a threshold. The threshold may be configured or fixed, or the WTRU may receive an indication of the threshold. The indication may be received via, for example, DCI, MAC or RRC configuration. The WTRU may transmit a repetition element (e.g., CG-UCI, DM-RS, UCI, or TB) in at least one of the orphaned symbols. This may be beneficial to maintain the COT and reduce the need for LBT before transmitting the remainder of the nominal repetition 2.

The WTRU may transmit UCI in an isolated symbol. The WTRU may transmit UCI on PUSCH in an isolated symbol. In one embodiment, if the WTRU is configured with Physical Uplink Control Channel (PUCCH) resources in isolated symbols, the WTRU may transmit UCI on the PUCCH. In such cases, subsequent repetitions (e.g., associated repetitions) of the nominal repetition may include UCI on PUSCH or may not include UCI at all.

If the WTRU is configured for cross-repetition or cross-slot DM-RS, the WTRU may transmit the DM-RS on an isolated symbol.

The WTRU may transmit a greater number of symbols than the number of symbols in the nominal repetition to keep the channel occupied. The WTRU may transmit a greater number of actual repetitions than is needed (e.g., a configured number) to maintain the COT. The WTRU may determine that another new TB arrives within a certain 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 keep the channel occupied until the next TB arrives in the WTRU buffer and/or may transmit it. The WTRU may determine TB arrival based on the configured traffic pattern. In one example, the WTRU may already have a buffer bit for transmission on the new TB, but transmitting the nominal repetition of the new TB may require waiting for another UL slot or a different PUSCH occasion (e.g., after a DL outage), or the number of slots and/or UL symbols remaining before the DL outage may not allow the WTRU to transmit the new TB. Even if it exceeds the number of symbols in the configured nominal repetition and/or the required repetition, the WTRU may transmit additional symbols and/or repetitions of the current TB to keep the channel occupied until: DL outage time, next FFP idle period, co may be shared with the gNB, an indication of a stop received from the gNB, or the WTRU may acquire an uplink slot that may be used to transmit new data, possibly on the same HARQ process.

The WTRU may repeat the TB until the time (e.g., CG timer) expires, or when it is determined that the x time of the HARQ process has been exceeded, or until an HARQ-ACK equal to the ACK on the Downlink Feedback Information (DFI) is received. In one example, the WTRU may utilize transmissions of different HARQ processes y to keep the channel occupied until it is determined that the CG retransmission time for pending HARQ process x has been exceeded (e.g., CG retransmission timer expired). This may enable the WTRU to retransmit the TB and/or repetition of HARQ process x immediately after determining that the CG retransmission time has been exceeded (e.g., upon expiration of the CG retransmission timer).

The WTRU may repeat transmitting until a configured number of repetitions (e.g., rep K) or until a next downlink slot or downlink symbol. The WTRU may receive an indication from Downlink Control Information (DCI) or Radio Resource Control (RRC) indicating a configuration grant within which the WTRU may transmit a repetition until a next downlink is encountered. This may help to maintain repeated transmission bursts until the next downlink slot or until an idle period or until the COTs can be released or shared with the gNB.

The WTRU may multiplex UCI on the uplink channel (e.g., CG-UCI on PUSCH) that is transmitting additional symbols and/or additional repetition (e.g., to maintain or until the end of the COT). The UCI may include an additional symbol or number of additional repetitions in the current COT or relative to the bundle size.

In one embodiment, the gNB may inform the WTRU of the dynamic number of repetitions and/or symbols to be used for transmitting the actual repetition during the UL transmission opportunity after DL (possibly in a shared COT). For example, in the case where split TDD in a slot or frame is configured as DUUUU-DUUUU, the WTRU may transmit an actual repetition of four symbols, even if the nominal repetition is three symbols (or slots), to ensure that the COT is maintained to the next DL symbol or slot, the next FFP, or idle period, or until the indicated amount of uplink symbols or slots has been exceeded. The WTRU may transmit additional symbols of the actual repetition upon receiving the indication from the gNB, wherein the number of symbols may be greater than the nominal repetition. The WTRU may transmit additional repetitions upon receiving an indication from the gNB, where the number of repetitions may be greater than the configured number of repetitions. The indication from the gNB may indicate a number of symbols applicable to the remaining repetition, a number of symbols applicable to the remaining repetition in the current/shared COT, a number of additional repetitions, or a number of additional repetitions in the current/shared COT.

The WTRU may transmit a smaller number of UL symbols in the actual repetition than the number of symbols in the nominal repetition. For example, the WTRU may transmit on multiple symbols or isolated symbols to maintain the COT. The WTRU may be configured with a minimum number of symbols. The configuration may be performed by a higher layer. If the number of symbols in the actual repetition is less than the minimum number of symbols, the WTRU may transmit the repetition, but not count it to the configured target number of repetitions, or the WTRU may not transmit the repetition at all.

Upon encountering a UL LBT failure, the WTRU may defer, skip, or cancel the repetition. The WTRU may increment a repetition count if repetitions have been transmitted.

When the WTRU encounters a UL LBT failure for repetition, receives a cancel indication, or discards the repetition due to, for example, inter/intra WTRU prioritization, the WTRU may either continue with the remaining repetition or terminate transmitting the remaining repetition when it encounters the next transmission opportunity. The WTRU may discard, skip, delay, or cancel the repetition. When reacquiring the channel, the WTRU may continue to transmit repetitions if the repetition count is below a predetermined threshold and/or if the number of UL symbols per previously transmitted repetition is equal to a nominal repetition. The predetermined threshold may be configured for the WTRU by, for example, RRC, MAC control element (MAC-CE), or DCI.

The WTRU may receive DCI MAC CE or RRC signaling indicating to resume transmission of the remaining repetitions and/or a configuration grant within which the WTRU may continue with the remaining repetitions. The WTRU may receive DCI or RRC indicating the HARQ ID that the WTRU may use to transmit the remaining repetitions. The WTRU may receive an explicit indication from the gNB to interrupt or cancel the remaining repetitions while the WTRU waits for the next uplink slot to complete the specified number of repetitions. The WTRU may cancel or suspend repetition before the repetition count reaches a configured number of repetitions (e.g., rep K), which may be for a given HARQ process. For example, the WTRU may receive a dynamic notification in DCI or MAC-CE in a different COT than the one used to transmit the initial set of repetitions to terminate or suspend the repetition from the network in the downlink slot. The WTRU may cancel the remaining repetitions if they are discarded due to network signaling (e.g., due to receiving a cancel indication from the gNB), but may not cancel the remaining repetitions if they are discarded due to LBT failure or intra-WTRU prioritization (in which case the gNB may not know those repetitions are discarded/not transmitted).

The WTRU may use different LBT configurations (e.g., channel Access Priority Class (CAPC), LBT class, or changing LBT parameters) to transmit repetitions of failing the LBT (e.g., based on the number of failed LBTs or such as counting the number of LBT failures in the MAC layer).

The WTRU may change the number of UL symbols and/or slots used to transmit the actual repetition after acquiring another COT to transmit the remaining repetition. The change may be based on, for example, the number of UL slots and/or symbols available in the new COT and the UL resource allocation available (e.g., the configuration of CG in the new COT and/or the allocation of dynamic grants provided in the new COT). The WTRU may include UCI multiplexed on PUSCH (e.g., CG-UCI) indicating HARQ processes, TB indexes, and/or applicable repeated RVs. The WTRU may skip incrementing the RV number when LBT fails for a repetition within the sequence. The WTRU may indicate in UCI that a subset of past repetitions were discarded due to LBT failure or intra-WTRU de-prioritization (e.g., to facilitate soft combining). For example, the WTRU may indicate that a previous set of repetitions was discarded in CG-UCI transmitted in a first subsequent repetition after the set of discarded repetitions. The indication may include the identity or number of previous repetitions that were discarded. The indication may be included in a plurality of subsequent CG-UCAs (e.g., for robustness). The bitmap may be included in a set of duplicate CG-UCI with the tag discarded.

UL LBT failure counters or indicators may be maintained at each repetition or group of repetitions or each LBT attempt. For example, UL LBT failure may be incremented by 1 each time LBT fails, or may be incremented by the number of repetitions (e.g., actual or nominal) that are discarded due to LBT failure. If the repetition has multiple start times, the UL LBT failure counter may be incremented if no repetition start time is considered valid for all LBT failures. If the nominal repetition is segmented into multiple actual repetitions, the UL LBT failure counter may be incremented for each failure to transmit an actual repetition or if all actual repetitions fail.

WTRU transmission repetition (e.g., type a or type B) may be limited based on which device initiated the COT. For example, the WTRU may be limited to transmitting repetitions only on the gcb-initiated COT, the WTRU-initiated COT, or both. Whether repetition is allowed on the gcb-initiated COT, the WTRU-initiated COT, or both may be indicated by RRC semi-static configuration or via DCI. The WTRU may be configured to allow only type a, type B, or type a and type B repetition based on which device initiated the COT.

The WTRU may select the COT to transmit the repetition based on the length of the FFP or the remaining FFP duration. For example, if the length of the repeat transmission exceeds the remaining time of the gNB FFP and the WTRU is configured with an upcoming FFP of a duration long enough to accommodate the repeat duration, the WTRU may transmit the repeat on the WTRU-initiated COT. If the configured FFP start time by the WTRU occurs too far into the future, or if the configured WTRU-initiated COT FFP duration is insufficient to transmit a complete repetition, the WTRU may rate match the repetition to accommodate the remaining gcb FFP duration.

If WTRU-initiated COT is used to transmit repetitions, the WTRU may be configured with dedicated WTRU-initiated COT FFP parameters, such as: FFP periodicity, start offset, and FFP duration. The configuration may be semi-statically configured via dedicated signaling (e.g., via RRC signaling, via MAC CE, or via DCI). FFP parameters may be mapped to repetition types (e.g., type a or type B) and/or repetition parameters (e.g., repetition duration and number of repetitions).

If the repeated transmissions are scheduled to begin directly after successful Clear Channel Assessment (CCA) (i.e., at the beginning of the FFP initiated by the WTRU), the WTRU may initiate a WTRU-initiated COT. If the WTRU is configured with multiple FFP configurations, the WTRU may select an FFP configuration where the FFP begins to coincide with the start of the scheduled repeat transmission. If the scheduled repetition start does not coincide with the start of the FFP start time initiated by the WTRU, the WTRU may transmit (e.g., fill bits) to initiate a channel until the scheduled repetition.

If the idle period interrupts the WTRU from repeating transmissions, the WTRU may cancel the remaining repeated transmissions. The WTRU may suspend transmission until the idle period is completed and resume repetition at the beginning of a new FFP. The WTRU may distinguish how the idle period affects the retransmission process depending on whether the idle period is sent by the gNB or the WTRU. For example, if the idle period occurs at the end of the FFP initiated by the WTRU, the WTRU may cancel the remaining repeated transmissions. If the WTRU is sharing the COT initiated by the gNB, the WTRU may suspend transmission until the idle period is completed and resume repeated transmissions.

The WTRU may determine an overlap between PUSCH repetition of a first priority (e.g., priority index 0) and PUCCH or PUSCH transmission of a second priority (e.g., priority index 1). It may be beneficial to avoid the need for transmission gaps of LBT before subsequent repetitions.

In one embodiment, the WTRU may cancel PUSCH repeated transmissions of a first priority (e.g., priority index 0) for time symbols that overlap with transmissions of another priority (e.g., priority index 1). In the remaining time symbols, the WTRU may transmit the same modulation symbols and reference signals as if cancellation did not occur in the overlapping symbols.

In one embodiment, to determine a set of actual repetitions from the nominal repetitions according to a procedure defined for PUSCH repetition type B, the WTRU may treat the time symbols where there is overlap as "invalid symbols". Non-overlapping symbols may be considered "potentially valid" symbols, and the WTRU may define the actual repetition as consecutive sets of potentially valid symbols. Based on rules applicable to PUSCH repetition type B, the WTRU may transmit even the actual repetition of a single symbol in this scenario, even though it would not have been.

In one embodiment, the WTRU may determine that there is an actual repetition of a set of consecutive symbols that overlap. The WTRU may multiplex the overlapping transmissions and the actual repetition of priority index 1 into a single transmission. Such an embodiment may be applicable in case the transmission of priority index 1 is a PUCCH transmission and supports multiplexing UCI of priority index 1 on PUSCH of priority index 0.

The WTRU may be configured or authorized with resources on which to transmit multiple TBs. Each TB may have multiple repetitions. The time resources for each repetition of each TB may be determined based on the mapping rules. The mapping rule may first loop through all repetitions of a TB, and then loop through all repetitions of a subsequent TB. The mapping rule may cycle through all first repetitions of all TBs and then through all second repetitions of all TBs.

Fig. 9 shows an example of repeated mapping when multi-TTI scheduling is used, and a transmission cycle of each TB is first followed by each repeated transmission cycle. In fig. 9, there are three TBs, each with two repetitions, and each nominal transmission includes five symbols. As shown in fig. 9, a repetition of TB (repetition 1 of TB 1, repetition 1 of TB 2, repetition 1 of TB 3) is transmitted, and then a second repetition of TB (repetition 2 of TB 1, repetition 2 of TB 2, repetition 2 of TB 3) is transmitted.

Fig. 10 shows an example of repeated mapping when multi-TTI scheduling is used, and a transmission cycle of each TB is first repeated and then each transmission cycle of the TB. In fig. 10, there are three TBs, each with two repetitions, and each nominal transmission includes five symbols. As shown in fig. 10, all repetitions of the first TB (repetition 1 of TB 1, repetition 2 of TB 1) are transmitted, then all repetitions of the second TB (repetition 1 of TB 2, repetition 2 of TB 2) are transmitted, and then all repetitions of the third TB (repetition 1 of TB 3, repetition 2 of TB 3) are transmitted.

Each of the repetitions shown in fig. 9 and 10 may be a nominal repetition, and the nominal repetition may be split or segmented into a plurality of actual repetitions. In fig. 9, the nominal repetition TB 2, rep 1 is split into two actual repetitions, the nominal repetition TB 3, rep 1 is split into two actual repetitions, the nominal repetition TB 2, rep 2 is split into two actual repetitions, and the nominal repetition TB 3, rep 2 is split into two actual repetitions. In fig. 10, the nominal repetition TB 1, rep 2 is split into two actual repetitions, the nominal repetition TB 2, rep 1 is split into two actual repetitions, the nominal repetition TB 3, rep 1 is split into two actual repetitions, and the nominal repetition TB 3, rep 2 is split into two actual repetitions.

For the case of scheduling WTRUs by using a repeated single TB, both embodiments (cycle per TB of fig. 9, then each repeated cycle and first each repeated cycle of fig. 10, then each TB cycle) produce the same results. Similarly, for the case of a WTRU scheduled by a single repetition per TB, both embodiments (cycle per TB of fig. 9, then cycle per repetition and first cycle per repetition of fig. 10, then cycle per TB) produce the same result. In this case, the WTRU may transmit a set of TBs using a sub-slot multi-TTI schedule. This may enable n TBs to be transmitted in m slots, where m < n.

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

The WTRU may be configured with a table with elements indicating the number of repetitions, slot offset, slot periodicity, and the number of TBs. The scheduling DCI may provide an index that points to a set of parameters found in a table.

Fig. 11 shows an example of a cycle with a single TB per slot. In this example, TB 1 has 3 repetitions of 3 symbols each, TB2 has 3 repetitions of 4 symbols each, and TB 3 has 5 repetitions of 2 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 fig. 11, TB 1 is transmitted in slot 1 and slot 4, TB2 is transmitted in slot 2 and slot 5, and TB 3 is transmitted in slot 3 and slot 6. The nominal repetition of a TB may be split or segmented and may span multiple non-adjacent time slots. For example, the second nominal repetition of TB2 in this example is split and the first actual repetition is transmitted in the second time slot and the second actual repetition is transmitted in the fifth time slot.

The WTRU may determine the elements of repetition based on the number of repetitions or the number of different TBs in the slot. For example, if all repetitions within a slot are for the same TB, the WTRU may transmit a single DM-RS in the slot.

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

For configuration 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 a fixed increment method or may be indicated by the WTRU in at least one CG-UCI.

In one embodiment, the WTRU may grant or configure resources to transmit repetitions of the TB across multiple slots. For example, the WTRU may have a nominal repetition that is longer in duration than the duration of the time slot. In such cases, the WTRU may segment the repetition and transmit different portions of the TB in different actual repetitions. For example, a nominal repetition may be segmented into a plurality of actual repetitions, and the TB may be segmented such that a portion of the TB is transmitted in each of the actual repetitions associated with the nominal repetition.

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

The WTRU may receive HARQ-ACKs for at least one TB of a group of TBs scheduled via multi-TTI scheduling. Upon receiving an ACK for a TB, the WTRU may not need to continue transmitting repetitions for the TB. In some embodiments, not repeating for a single TB transmission may result in a transmission gap being created, which may result in the need to perform LBT before other repetitions.

The WTRU may reuse the resources originally allocated to the first TB (e.g., for which the WTRU has received an ACK) to transmit a repetition of the second TB. The second TB may be a TB for which the WTRU has transmitted some repetitions. The second TB may be a new TB for which the WTRU has not transmitted any repetition.

In one embodiment, the WTRU may offset the remaining repetitions and TBs to use the resources originally allocated to the TBs that have been acknowledged (ACKed).

In one embodiment, the WTRU may be allocated resources for repetition of HARQ processes (e.g., rather than for a particular TB). The WTRU may receive an indication that a new TB is transmitted using the HARQ process for which the WTRU has received an ACK. The indication may be received by the WTRU in the same message (e.g., CG-DFI) that it received the ACK. The indication may be received in a new DCI. The indication may be received via RRC signaling. The new TB may be transmitted using the repetition resource associated with the HARQ process. Different HARQ processes may have different repetition numbers. The WTRU may include an indication of the repetition number in an element of repetition (e.g., CG-UCI).

In one embodiment, the WTRU may remap the remaining repetitions to account for the newly free UL resources that were originally mapped to the ACKed TB. Such remapping may be indicated to the WTRU or autonomously determined by the WTRU. The WTRU may acknowledge the remapping to the gNB before remapping the remaining TBs. In one embodiment, the WTRU may be triggered to transmit at least one element (e.g., CG-UCI or UCI) in a remapped repetition.

The WTRU may cycle through different TBs in the multi-TTI grant. Each TB may be mapped to a different slot and each slot may be associated with a different HARQ process. In a slot, a WTRU may include one or more repetitions for an associated HARQ process. The WTRU may or may not use the slot to complete the required number of repetitions. If the WTRU does not complete the required number of repetitions, the WTRU may complete transmission of the remaining repetitions on a subsequently scheduled multi-TTI grant (or other grant).

For a given multi-TTI grant, the WTRU may transmit on all TTIs after a single LBT for any TTI. Once the LBT for a given TTI fails, the WTRU may attempt another LBT procedure for the next TTI. For TB transmission attempt failure for a given TTI due to LBT, the WTRU may cycle to the next TB/HARQ process. The WTRU may skip or defer repeated transmissions of LBT failures and behave as if they had been transmitted.

If the HARQ process for the next TTI does not contain pending TBs (e.g., no other/previous pending TBs are transmitted on the HARQ process associated with the slot) and/or LBT failed TBs are not previously transmitted on a different HARQ process, the WTRU may map the LBT failed TB transmission to a different TTI in the next TTI or grant. The different TTI may be the first TTI available in the grant after the WTRU completes cycling through TBs. For example, the WTRU may append TB repetitions at the end (e.g., at the end of the grant) after cycling through other HARQ processes. The WTRU may multiplex HARQ processes associated with discarded TB/repetition portions of UCI multiplexed on PUSCH transmissions. This may depend on or be based on whether the TTI selected over which the TB/repetition is transmitted is associated with a different HARQ process than the one used for the initial transmission of the TB.

The WTRU may skip the repetition of LBT failure if multiple repetitions of a TB are transmitted before cycling to another TB. If all TBs are cycled first, the WTRU may delay TB transmission until the next LBT successful PUSCH occasion. The WTRU may shift the transmission sequence by a specific offset upon LBT failure to transmit a given repetition on a multi-TTI grant. The offset may be configured (e.g., by higher layers, RRC, or DCI) or predetermined as the number of repetitions per TB. In an exemplary transmission (x.y), x may be a TB number and y may be a repetition number. The WTRU may transmit the following TB repetitions using the first round robin method, assuming four TBs are present, each of the TBs being repeated twice: 1.1 1.2 2.1 2.2 3.1 3.2 4.1 4.2. In a second round robin approach, the WTRU may transmit the following TB repetition: 1.1 2.1 3.1 4.1 1.2 2.2 3.2 4.2. If the WTRU uses the second round robin method and fails LBT for 1.1, the WTRU may skip 2.1 transmissions because the WTRU may not transmit anything of the first TB until the fourth opportunity. If LBT fails for transmission repetition, the WTRU may shift the entire TB transmit sequence by a certain offset.

The WTRU may be configured with a common SLIV/K for all TBs within the multi-slot transmission. Alternatively, SLIV/K may be configured separately for each TB. Whether a common repetition configuration or a 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 (or associated overhead) method for indicating repetition parameters (e.g., via RRC tables or DCI), or the channel characteristics (e.g., reference Signal Received Power (RSRP)).

The repetition parameter for each TB may depend on, for example, one or more of the following: characteristics of the TB (e.g., TB length or QoS requirements); scheduled resources (e.g., location of TB start/end within a slot) are transmitted for TBs; the relative positions of consecutive TBs (e.g., in a TDD scenario, if two TBs are scheduled close together in time, the first TB may be limited to a potential number of repetitions); a slot format of a slot in which a specific TB is transmitted; or channel characteristics (e.g., RSRP, channel occupancy).

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

The repetition parameters may be semi-statically configured (e.g., via RRC signaling) and stored via a table. The table may be configured separately, wherein the multi-slot scheduling DCI may indicate repetition parameters to be used for TBs within grants via a pointer to a specific SLIV/K. A table (e.g., RRC table) may be used to indicate resources for multi-TB transmission and may indicate a repetition format/parameter for each TB.

Although the features and elements are described above in particular combinations, one of ordinary skill in the art will appreciate that each feature or element can be used alone or in any combination with other features and elements. Furthermore, the methods described herein may be implemented in a computer program, software, or firmware incorporated in a computer readable medium for execution by a computer or processor. Examples of computer readable media include electronic signals (transmitted over a wired or wireless connection) and computer readable storage media. Examples of computer readable storage media include, but are not limited to, read-only memory (ROM), random-access memory (RAM), registers, cache memory, semiconductor memory devices, magnetic media (such as internal hard disks and removable disks), magneto-optical media, and optical media (such as CD-ROM disks and Digital Versatile Disks (DVDs)). A processor associated with the software may be used to implement a radio frequency transceiver for a WTRU, UE, terminal, base station, RNC, or any host computer.

Claims (20)

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

a transceiver; and

a processor, wherein:

the transceiver and the processor are configured to receive information to transmit uplink data, wherein the information indicates 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 the first scalar complex; and

the transceiver and the processor are further configured to transmit a second number of actual repetitions in a symbol associated with the first scalar complex, wherein the second number of actual repetitions and the symbol for transmitting the second number of actual repetitions are based on events occurring during the set of symbols associated with the first scalar complex.

2. The WTRU of claim 1, wherein the event is at least one of: channel Occupancy Time (COT) end, channel access resources, channel access procedure result, fixed Frame Period (FFP) idle period start time, or FFP idle period end time.

3. The WTRU of claim 1, wherein the set of symbols associated with the first scalar complex comprises one or more sub-sets of contiguous uplink symbols.

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

5. The WTRU of claim 4, wherein:

the transceiver and the processor are further configured to, on condition that the event occurs during the set of symbols associated with the first scalar complex:

transmitting a first actual repetition in one or more of the one or more sub-sets of consecutive uplink symbols before the event occurs; and

transmitting a second actual repetition after transmitting the first actual repetition in one or more of the one or more sub-set of consecutive uplink symbols after the occurrence of the event on condition that the channel access procedure is successful.

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

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

8. The WTRU of claim 5, wherein the channel access procedure is based on at least one of: channel Occupancy Time (COT) timing, the originator of the COT, fixed Frame Period (FFP) timing, previous channel access procedure results, whether there is a gap before repetition, the size of the gap between repetitions, or the reason for generating the gap between repetitions.

9. The WTRU of claim 1, wherein an actual repetition of the second number of actual repetitions comprises at least one of: configuration grants 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).

10. 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, wherein the resources include at least one of: a set of time instances, a set of frequency ranges, or beams.

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

receiving information to transmit uplink data, wherein the information indicates 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 the first scalar complex; and

transmitting a second number of actual repetitions in symbols associated with the first scalar complex, wherein the second number of actual repetitions and the symbols for transmitting the second number of actual repetitions are based on events occurring during the set of symbols associated with the first scalar complex.

12. The method of claim 11, wherein the event is at least one of: channel Occupancy Time (COT) end, channel access resources, channel access procedure result, fixed Frame Period (FFP) idle period start time, or FFP idle period end time.

13. The method of claim 11, wherein the set of symbols associated with the first scalar complex comprises one or more subgroups of contiguous uplink symbols.

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

15. The method of claim 14, the method further comprising:

on condition that the event occurs during the set of symbols associated with the first scalar complex:

transmitting a first actual repetition in one or more of the one or more sub-sets of consecutive uplink symbols before the event occurs; and

transmitting a second actual repetition after transmitting the first actual repetition in one or more of the one or more sub-set of consecutive uplink symbols after the occurrence of the event on condition that the channel access procedure is successful.

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

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

18. The method of claim 15, wherein the channel access procedure is based on at least one of: channel Occupancy Time (COT) timing, the originator of the COT, fixed Frame Period (FFP) timing, previous channel access procedure results, whether there is a gap before repetition, the size of the gap between repetitions, or the reason for generating the gap between repetitions.

19. The method of claim 11, wherein an actual repetition of the second number of actual repetitions comprises at least one of: configuration grants 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).

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