Method and apparatus for HARQ enhancement

Abstract

Methods, apparatuses, and systems for hybrid automatic repeat request (HARQ) enhancements in wireless communications are provided.SOLUTION: A method implemented in a wireless transmit / receive unit (WTRU) for wireless communication includes identifying a codebook process from a set of codebook processes based on a first indication, associating a set of bits of hybrid automatic repeat request (HARQ) feedback with the identified codebook process, maintaining the set of bits associated with the identified codebook process based on a condition, receiving a second indication to transmit the set of bits associated with the identified codebook process, and transmitting the set of bits based on the second indication.SELECTED DRAWING: Figure 3A

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Patent Application No. 62 / 715,458, filed August 7, 2018, and U.S. Provisional Patent Application No. 62 / 788,424, filed January 4, 2019, the contents of which are incorporated by reference herein for all purposes as if fully set forth herein in their respective entireties. [Background technology]

[0002] Mobile communications continue to evolve. The fifth generation, which may implement an advanced wireless communication system referred to as New Radio (NR), may be referred to as 5G. The embodiments disclosed herein generally relate to wireless and / or wired communication networks. For example, one or more embodiments disclosed herein relate to methods and apparatus for hybrid automatic repeat request (HARQ) enhancements in wireless communications. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] RP-172021, "Revised SID on NR-based Access to Unlicensed Spectrum", TSG RAN #77 [Non-patent document 2] 3GPP TS 38.213, “Physical layer procedures”, v15.0.0 [Non-patent document 3] 3GPP TR 36.889, “Feasibility Study in Licensed-Assisted Access to Unlicensed Spectrum”, v13.0.0 [Non-patent document 4] 3GPP TR 38.321, “Medium Access Control (MAC) protocol specification”, v15.1.0 [Brief explanation of the drawings]

[0004] A more detailed understanding may be had from the following detailed description, given by way of example in conjunction with the drawings attached hereto. The figures in the description are examples. Thus, the figures and detailed description should not be considered limiting, as other equally effective examples are possible and contemplated. Moreover, like reference numerals in the figures indicate like elements. [Figure 1A] FIG. 1 is a system diagram illustrating an example communication system in which one or more disclosed embodiments may be implemented. [Figure 1B] 1B is a system diagram illustrating an example wireless transmit / receive unit (WTRU) that may be used within the communication system illustrated in FIG. 1A, according to an embodiment. [Figure 1C] 1B is a system diagram illustrating an example radio access network (RAN) and an example core network (CN) that may be used within the communication system illustrated in FIG. 1A, according to an embodiment. [Figure 1D] 1B is a system diagram illustrating a further exemplary RAN and a further exemplary CN that may be used within the communication system illustrated in FIG. 1A, according to an embodiment. [Figure 2] 1 is a diagram illustrating a sequence of subframes in an example of HARQ feedback without clear channel assessment (CCA), according to one or more embodiments. [Figure 3A] 1 is a diagram illustrating an example of HARQ transmission at different channel occupation times (COTs), according to one or more embodiments. [Figure 3B] 1A-1C are two tables illustrating two examples of reusing one or more PDSCH-to-HARQ timing indicators in downlink control information (DCI), according to one or more embodiments. [Figure 4]FIG. 10 illustrates a sequence of subframes in an example of HARQ feedback with a counter downlink allocation index (DAI), according to one or more embodiments. [Figure 5] FIG. 1 illustrates an example of using multiple physical uplink control channel (PUCCH) resources for HARQ transmissions, according to one or more embodiments. [Figure 6] 10A-10C illustrate examples of configuring an offset along with an acknowledgement resource indicator (ARI) when selecting from a PUCCH resource set, according to one or more embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0005] Communications Networks and Devices 1A is a diagram illustrating an example communication system 100 in which one or more disclosed embodiments may be implemented. The communication system 100 may be a multiple-access system that provides content, such as voice, data, video, messaging, broadcasts, and the like, to multiple wireless users. The communication system 100 may facilitate access to such content by multiple wireless users through the sharing of system resources, including wireless bandwidth. For example, the communication system 100 may employ one or more channel access methods, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single-carrier FDMA (SC-FDMA), zero-tailed unique word DFT-spread OFDM (ZT UW DTS-sOFDM), unique word OFDM (UW-OFDM), resource block filtered OFDM, filter bank multicarrier (FBMC), etc.

[0006] 1A, communications system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, RANs 104 / 113, CNs 106 / 115, public switched telephone network (PSTN) 108, the Internet 110, and other networks 112, although it will be appreciated that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network elements. Each of WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and / or communicate in a wireless environment. For example, the WTRUs 102a, 102b, 102c, 102d, any of which may be referred to as a “station” and / or “STA,” may be configured to transmit and / or receive wireless signals and may include user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a subscription-based unit, a pager, a cellular phone, a PDA, a smartphone, a laptop, a netbook, a personal computer, a wireless sensor, a hotspot or Mi-Fi device, an IoT device, a watch or other wearable, a head-mounted display (HMD), a vehicle, a drone, a medical device and application (e.g., remote surgery), an industrial device and application (e.g., robots and / or other wireless devices operating in an industrial and / or automated processing chain context), a consumer electronic device, a device operating on a commercial and / or industrial wireless network, etc. Any of the WTRUs 102a, 102b, 102c, and 102d may be referred to interchangeably as a UE.

[0007] The communications system 100 may also include a base station 114a and / or a base station 114b. Each of the base stations 114a, 114b may be any type of device configured to wirelessly interface with at least one of the WTRUs 102a, 102b, 102c, 102d to facilitate access to one or more communications networks, such as the CN 106 / 115, the Internet 110, and / or other networks 112. For example, the base stations 114a, 114b may be a base transceiver station (BTS), a Node-B, an eNodeB, a Home NodeB, a Home eNodeB, a gNB, a New Radio (NR) NodeB, a site controller, an access point (AP), a wireless router, etc. Although the base stations 114a, 114b are each depicted as a single element, it will be appreciated that the base stations 114a, 114b may include any number of interconnected base stations and / or network elements.

[0008] The base station 114a may be part of the RAN 104 / 113, which may also include other base stations and / or network elements (not shown), such as a base station controller (BSC), a radio network controller (RNC), relay nodes, etc. The 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 the licensed spectrum, the unlicensed spectrum, or a combination of the licensed and unlicensed spectrum. A cell may provide coverage for wireless services in a specific geographic area, which may be relatively fixed or may change over time. A cell may be further divided into cell sectors. For example, the cell associated with the base station 114a may be divided into three sectors. Thus, in one embodiment, the base station 114a may include three transceivers, e.g., one for each sector of the cell. In an embodiment, the base station 114a may employ MIMO technology and utilize multiple transceivers per sector of the cell. For example, beamforming may be used to transmit and / or receive signals in desired spatial directions.

[0009] The base stations 114a, 114b may communicate with one or more of the WTRUs 102a, 102b, 102c, 102d over an air interface 116, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet (UV), visible light, etc.). The air interface 116 may be established using any suitable radio access technology (RAT).

[0010] More specifically, as noted above, the 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, etc. For example, the base stations 114a and WTRUs 102a, 102b, 102c in the RAN 104 / 113 may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may establish the air interface 115 / 116 / 117 using Wideband CDMA (WCDMA). WCDMA may include 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 ​​UL Packet Access (HSUPA).

[0011] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which may establish the air interface 116 using Long Term Evolution (LTE) and / or LTE-Advanced (LTE-A) and / or LTE-Advanced Pro (LTE-A Pro).

[0012] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as New Radio (NR) radio access, which may establish the air interface 116 using NR.

[0013] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement multiple radio access technologies. For example, the base station 114a and the WTRUs 102a, 102b, 102c may jointly implement LTE and NR radio access 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).

[0014] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement a wireless technology such as IEEE 802.11 (e.g., Wireless Fidelity (WiFi)), IEEE 802.16 (e.g., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile Communications (GSM), Enhanced Data Rates for GSM Evolution (EDGE), GSM EDGE (GERAN), or others.

[0015] 1A may be a wireless router, a Home NodeB, a Home eNodeB, or an access point and may utilize any suitable RAT for facilitating wireless connectivity in a localized area, such as a business, a home, a vehicle, a campus, an industrial facility, an air corridor (e.g., for use by drones), a road, or other location. In one embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.11 to establish a wireless local area network (WLAN). In an embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.15 to establish a wireless personal area network (WPAN). In yet another embodiment, the base station 114b and the WTRUs 102c, 102d may utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.) to establish a picocell or femtocell. 1A, the base station 114b may have a direct connection to the Internet 110. Thus, the base station 114b may not be required to access the Internet 110 via the CN 106 / 115.

[0016] The RAN 104 / 113 may be in communication with the CN 106 / 115, which may be any type of network configured to provide voice, data, application, and / or VoIP services to one or more of the WTRUs 102a, 102b, 102c, 102d. The data may have diverse quality of service (QoS) requirements, such as different throughput requirements, latency requirements, error resilience requirements, reliability requirements, data throughput requirements, mobility requirements, etc. The CN 106 / 115 may provide call control, billing services, mobile location services, prepaid calling, Internet connectivity, video distribution, etc., and / or perform high-level security functions such as user authentication. Although not shown in FIG. 1A , it will be appreciated that the RAN 104 / 113 and / or the CN 106 / 115 may be in direct or indirect communication with other RANs employing the same RAT as the RAN 104 / 113 or a different RAT. For example, the CN 106 / 115, in addition to being connected to the RAN 104 / 113, which may utilize NR radio technology, may also be in communication with another RAN (not shown) that employs GSM, UMTS, CDMA2000, WiMAX, E-UTRA, or WiFi radio technology.

[0017] The CN 106 / 115 may also serve as a gateway for the WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the Internet 110, and / or other networks 112. The PSTN 108 may include a circuit-switched telephone network providing plain old telephone service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices that use common communication protocols, such as TCP, UDP, and / or IP in the TCP / IP Internet protocol suite. The network 112 may include wired and / or wireless communication networks owned and / or operated by other service providers. For example, the network 112 may include another CN connected to one or more RANs, which may employ the same RAT as the RAN 104 / 113 or a different RAT.

[0018] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communications system 100 may include multi-mode capabilities (e.g., the WTRUs 102a, 102b, 102c, 102d may include multiple transceivers for communicating with different wireless networks over different wireless links.) For example, the WTRU 102c shown in FIG. 1A may be configured to communicate with a base station 114a that may employ a cellular-based wireless technology and with a base station 114b that may employ IEEE 802.11 wireless technology.

[0019] 1B is a system diagram illustrating an example 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 GPS chipset 136, and / or other peripherals 138. It will be appreciated that the WTRU 102 may include any sub-combination of the above-described elements while remaining consistent with an embodiment.

[0020] The processor 118 may be a general-purpose processor, a special-purpose processor, a conventional processor, a digital signal processor (DSP), multiple microprocessors, one or more microprocessors in association with a DSP core, a controller, a microcontroller, an ASIC, an FPGA circuit, any other type of integrated circuit (IC), a state machine, etc. The processor 118 may perform signal coding, data processing, power control, input / output processing, and / or any other functionality that facilitates the WTRU 102 operating in a wireless environment. The processor 118 may be coupled to the transceiver 120, which may be coupled to the transmit / receive element 122. While FIG. 1B depicts the processor 118 and the transceiver 120 as separate components, it will be appreciated that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip.

[0021] The transmit / receive element 122 may be configured to transmit signals to or receive signals from a base station (e.g., base station 114a) over the air interface 116. For example, in one embodiment, the transmit / receive element 122 may be an antenna configured to transmit and / or receive RF signals. In an embodiment, the transmit / receive element 122 may be an emitter / detector configured to transmit and / or receive, for example, IR signals, UV signals, or visible light signals. In yet another embodiment, the transmit / receive element 122 may be configured to transmit and / or receive both RF signals and light signals. It will be appreciated that the transmit / receive element 122 may be configured to transmit and / or receive any combination of wireless signals.

[0022] 1B as a single element, the WTRU 102 may include any number of transmit / receive elements 122. More specifically, the WTRU 102 may employ MIMO technology. Thus, in one embodiment, the WTRU 102 may include two or more transmit / receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals over the air interface 116.

[0023] 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 mentioned above, the WTRU 102 may have multi-mode capabilities. Thus, the transceiver 120 may include multiple transceivers that facilitate the WTRU 102 communicating via multiple RATs, such as, for example, NR and IEEE 802.11.

[0024] 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 (e.g., a liquid crystal display (LCD) display unit or an organic light emitting diode (OLED) display unit). The processor 118 may also output user data to the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128. The processor 118 may also access information from and store data in any type of suitable memory, such as non-removable memory 130 and / or removable memory 132. The non-removable memory 130 may include RAM, ROM, a hard disk, or any other type of memory storage device. The removable memory 132 may include a SIM card, a memory stick, a secure digital (SD) memory card, etc. In other embodiments, the processor 118 may access information from and store data in memory that is not physically located on the WTRU 102, such as on a server or home computer (not shown).

[0025] 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 cell batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel-metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, etc.

[0026] The processor 118 may also be coupled to a GPS chipset 136 that may be configured to provide location information (e.g., longitude and latitude) regarding the current location of the WTRU 102. In addition to, or instead of, information from the GPS chipset 136, the WTRU 102 may receive location information over the air interface 116 from a base station (e.g., base stations 114a, 114b) and / or determine its location based on the timing of signals being received from two or more nearby base stations. It will be appreciated that the WTRU 102 may obtain location information via any suitable location-determination method while remaining consistent with an embodiment.

[0027] The processor 118 may further be coupled to other peripherals 138, which may include one or more software and / or hardware modules that provide additional features, functionality, and / or wired or wireless connectivity. For example, the peripherals 138 may include an accelerometer, an electronic compass, a satellite transceiver, a digital camera (for photos and / or videos), a USB port, a vibration device, a television transceiver, a hands-free headset, a Bluetooth module, a frequency modulation (FM) radio unit, a digital music player, a media player, a video game player module, an internet browser, a virtual reality and / or augmented reality (VR / AR) device, an activity tracker, etc. The peripherals 138 may include one or more sensors, which may be one or more of a gyroscope, an accelerometer, a Hall-effect sensor, a magnetometer, an orientation sensor, a proximity sensor, a temperature sensor, a time sensor, a geolocation sensor, an altimeter, a light sensor, a touch sensor, a magnetometer, a barometer, a gesture sensor, a biometric sensor, and / or a humidity sensor.

[0028] The WTRU 102 may be associated with a particular subframe (e.g., for both the UL (e.g., for transmission) and the downlink (e.g., for reception). )It may include a full-duplex radio, where transmission and reception of some or all of the signals may be parallel and / or simultaneous. The full-duplex radio may include an interference management unit 139 to reduce and / or substantially eliminate self-interference, either through hardware (e.g., chokes) or signal processing via a processor (e.g., via a separate processor (not shown) or processor 118). In an embodiment, the WTRU 102 may include a half-duplex radio for transmission and reception of some or all of the signals (e.g., associated with a particular subframe for either the UL (e.g., for transmission) or downlink (e.g., for reception)).

[0029] 1C is a system diagram illustrating the RAN 104 and the CN 106, according to an embodiment. As noted above, the RAN 104 may employ E-UTRA radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 104 may also be in communication with the CN 106.

[0030] The RAN 104 may include eNodeBs 160a, 160b, and 160c, although it will be appreciated that the RAN 104 may include any number of eNodeBs while remaining consistent with an embodiment. The eNodeBs 160a, 160b, and 160c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, and 102c over the air interface 116. In one embodiment, the eNodeBs 160a, 160b, and 160c may implement MIMO technology. Thus, the eNodeB 160a, for example, may use multiple antennas to transmit wireless signals to and / or receive wireless signals from the WTRU 102a.

[0031] Each of the eNodeBs 160a, 160b, 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the UL and / or DL, etc. As shown in FIG. 1C, the eNodeBs 160a, 160b, 160c may communicate with one another over an X2 interface.

[0032] 1C may include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (or PGW) 166. While each of the above-mentioned elements is depicted as part of the CN 106, it will be appreciated that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0033] The MME 162 may be connected to each of the eNodeBs 160a, 160b, 160c in the RAN 104 via an S1 interface and may act as a control node. For example, the MME 162 may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, bearer activation / deactivation, selecting a particular serving gateway during initial attach of the WTRUs 102a, 102b, 102c, etc. The MME 162 may provide a control plane function for switching between the RAN 104 and other RANs (not shown) that employ other radio technologies, such as GSM and / or WCDMA.

[0034] The SGW 164 may be connected to each of the eNodeBs 160a, 160b, 160c in the RAN 104 via an S1 interface. The SGW 164 may generally route and forward user data packets to / from the WTRUs 102a, 102b, 102c. The SGW 164 may perform other functions such as anchoring the user plane during handovers between eNodeBs, triggering paging when DL data is available to the WTRUs 102a, 102b, 102c, managing and storing the context of the WTRUs 102a, 102b, 102c, etc.

[0035] The SGW 164 may be connected to a PGW 166, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communication between the WTRUs 102a, 102b, 102c and IP-enabled devices.

[0036] The CN 106 may facilitate communications with other networks. For example, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to circuit-switched networks, such as the PSTN 108, to facilitate communications between the WTRUs 102a, 102b, 102c and legacy landline communications devices. For example, the CN 106 may include or communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that acts as an interface between the CN 106 and the PSTN 108. The CN 106 may also 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.

[0037] Although the WTRU is described in Figures 1A-1D as a wireless terminal, it is contemplated that in certain representative embodiments that such a terminal may use (either temporarily or permanently), a wired communication interface with the communication network will be used.

[0038] In some representative embodiments, the other network 112 may be a WLAN.

[0039] A WLAN in infrastructure basic service set (BSS) mode may have an access point (AP) for the BSS and one or more stations (STAs) associated with the AP. The AP may have access or an interface to a distribution system (DS) or to another type of wired / wireless network that carries traffic into and / or out of the BSS. Traffic to a STA originating from outside the BSS may arrive through the AP and be delivered to the STA. Traffic originating from a STA to a destination outside the BSS may be sent to the AP to be delivered to the respective destination. For example, traffic between STAs within a BSS may be sent through the AP if the source STA can send the traffic to the AP, and the AP can deliver the traffic to the destination STA. Traffic between STAs within a BSS may be considered and / or referred to as peer-to-peer traffic. Peer-to-peer traffic may be sent between (e.g., directly between) a source STA and a destination STA using direct link setup (DLS). In certain representative embodiments, the DLS may use 802.11e DSL or 802.11z tunneled DLS (TDLS). A WLAN using an Independent BSS (IBSS) mode may not have an AP, and STAs within or using the IBSS (e.g., all of the STAs) can communicate directly with each other. The IBSS communication mode may sometimes be referred to herein as an "ad hoc" communication mode.

[0040] When using the 802.11ac infrastructure mode of operation or a similar mode of operation, an AP may transmit beacons on a fixed channel, such as a primary channel. The primary channel may be a fixed width (e.g., a 20 MHz wide bandwidth) or a width dynamically set via signaling. The primary channel may be the 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 with collision avoidance (CSMA / CA) may be implemented, for example, in an 802.11 system. With CSMA / CA, STAs (e.g., every STA), including the AP, may sense the primary channel. If the primary channel is sensed / detected by a particular STA and / or determined to be busy, the particular STA may back off. One STA (e.g., only one station) may transmit in a given BSS at any given time.

[0041] High-throughput (HT) STAs may, for example, use 40 MHz wide channels for communication via a combination of a primary 20 MHz channel and adjacent or non-adjacent 20 MHz channels to form 40 MHz wide channels.

[0042] A very high throughput (VHT) STA can support channels that are 20 MHz, 40 MHz, 80 MHz, and / or 160 MHz wide. A 40 MHz and / or 80 MHz channel may be formed by combining adjacent 20 MHz channels. A 160 MHz channel may be formed by combining eight adjacent 20 MHz channels or by combining two non-adjacent 80 MHz channels, sometimes referred to as an 80+80 configuration. For the 80+80 configuration, after channel encoding, the data may be passed through a segment parser that can split the data into two streams. Inverse fast Fourier transform (IFFT) processing and time-domain processing may be performed separately on each stream. The streams may be mapped onto two 80 MHz channels, and the data may be transmitted by the transmitting STA. At the receiver of the receiving STA, the operations described above for the 80+80 configuration may be reversed, and the combined data may be sent to the medium access control (MAC).

[0043] Sub-1 GHz operating modes are supported by 802.11af and 802.11ah. Channel operating bandwidths and carriers are reduced in 802.11af and 802.11ah compared to those used in 802.11n and 802.11ac. 802.11af supports 5 MHz, 10 MHz, and 20 MHz bandwidths in the TV White Space (TVWS) spectrum, while 802.11ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths using non-TVWS spectrum. According to representative embodiments, 802.11ah can support meter-type control / machine-type communications, such as MTC devices in macro coverage areas. MTC devices may have limited capabilities, including, for example, support for (e.g., only support for) certain and / or limited bandwidths. MTC devices may include batteries with above-threshold battery life (e.g., to maintain very long battery life).

[0044] WLAN systems capable of supporting multiple channels and channel bandwidths, such as 802.11n, 802.11ac, 802.11af, and 802.11ah, include a channel that may be designated as a primary channel. The primary channel may have a bandwidth equal to the largest common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel may be set and / or limited by the STA that supports the smallest bandwidth operating mode among all STAs operating in the BSS. In the example of 802.11ah, the primary channel may be 1 MHz wide for a STA (e.g., an MTC-type device) that supports (e.g., only supports) the 1 MHz mode, even if the AP and other STAs in the BSS support 2 MHz, 4 MHz, 8 MHz, 16 MHz, and / or other channel bandwidth operating modes. Carrier sensing and / or NAV settings may depend on the status of the primary channel. For example, if the primary channel is busy due to a STA (that only supports 1 MHz mode of operation) transmitting to the AP, the entire available frequency band may be considered busy, even though most of the frequency band may remain idle and available for use.

[0045] In the United States, the available frequency band that can be used by 802.11ah is from 902 MHz to 928 MHz. In South Korea, the available frequency band is from 917.5 MHz to 923.5 MHz. In Japan, the available frequency band is from 916.5 MHz to 927.5 MHz. The total available bandwidth for 802.11ah is from 6 MHz to 26 MHz, depending on the country code.

[0046] 1D is a system diagram illustrating the RAN 113 and the CN 115, according to an embodiment. As noted above, the RAN 113 may employ NR radio technology and communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 113 may also be in communication with the CN 115.

[0047] The RAN 113 may include gNBs 180a, 180b, and 180c, although it will be appreciated that the RAN 113 may include any number of gNBs while remaining consistent with the embodiment. The gNBs 180a, 180b, and 180c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, and 102c over the air interface 116. In one embodiment, the gNBs 180a, 180b, and 180c may implement MIMO technology. For example, the gNBs 180a and 180b may utilize beamforming to transmit signals to and / or receive signals from the WTRUs 102a, 102b, and 102c. Thus, the gNB 180a may, for example, use multiple antennas to transmit wireless signals to and / or receive wireless signals from the WTRU 102a. In an embodiment, the gNBs 180a, 180b, 180c may implement carrier aggregation technology. For example, the gNB 180a may transmit multiple component carriers to the WTRU 102a (not shown). A subset of these component carriers may be on an unlicensed spectrum, while the remaining component carriers may be on a licensed spectrum. In an embodiment, the gNBs 180a, 180b, 180c may implement coordinated multipoint (CoMP) technology. For example, the WTRU 102a may receive coordinated transmissions from the gNBs 180a and 180b (and / or 180c).

[0048] The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using transmissions associated with scalable numerology. For example, the OFDM symbol spacing and / or OFDM subcarrier spacing may vary for different transmissions, different cells, and / or different portions of the wireless transmission spectrum. The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using subframes or transmission time intervals (TTIs) of varying or scalable lengths (e.g., accommodating various numbers of OFDM symbols and / or lasting various lengths of absolute time).

[0049] The gNBs 180a, 180b, 180c may be configured to communicate with the WTRUs 102a, 102b, 102c in a standalone configuration and / or a non-standalone configuration. In a standalone configuration, the WTRUs 102a, 102b, 102c can communicate with the gNBs 180a, 180b, 180c without also accessing another RAN (e.g., eNodeBs 160a, 160b, 160c, etc.). In a standalone configuration, the WTRUs 102a, 102b, 102c can utilize one or more of the gNBs 180a, 180b, 180c as mobility anchor points. In a standalone configuration, the WTRUs 102a, 102b, 102c can communicate with the gNBs 180a, 180b, 180c using signals in unlicensed bands. In a non-standalone configuration, the WTRUs 102a, 102b, 102c may communicate / connect to a gNB 180a, 180b, 180c while also communicating / connecting to another RAN, such as an eNodeB 160a, 160b, 160c. For example, the WTRUs 102a, 102b, 102c may implement the DC principle to communicate with one or more gNBs 180a, 180b, 180c and with one or more eNodeBs 160a, 160b, 160c substantially simultaneously. In a non-standalone configuration, the eNodeBs 160a, 160b, 160c may act 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, 102c.

[0050] Each of the gNBs 180a, 180b, 180c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the UL and / or DL, support for network slicing, dual connectivity, interworking between NR and E-UTRA, routing of user plane data towards user plane functions (UPFs) 184a, 184b, routing of control plane information towards access and mobility management functions (AMFs) 182a, 182b, etc. As shown in FIG. 1D , the gNBs 180a, 180b, 180c may communicate with each other over an Xn interface.

[0051] 1D may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one Session Management Function (SMF) 183a, 183b, and possibly a Data Network (DN) 185a, 185b. While each of the above-mentioned elements is depicted as part of the CN 115, it will be appreciated that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0052] The AMF 182a, 182b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via an N2 interface and may act as a control node. For example, the AMF 182a, 182b may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, supporting network slicing (e.g., handling different PDU sessions with different requirements), selecting a particular SMF 183a, 183b, managing registration areas, terminating NAS signaling, mobility management, etc. Network slicing may be used by the AMF 182a, 182b to customize CN support for the WTRUs 102a, 102b, 102c based on the type of service utilized by the WTRUs 102a, 102b, 102c. For example, different network slices may be established for different use cases, such as services relying on Ultra-Reliable Low Latency (URLLC) access, services relying on Enhanced Massive Mobile Broadband (eMBB) access, services for Machine Type Communications (MTC) access, and / or others. The AMF 182 may provide a control plane function for switching between the RAN 113 and other RANs (not shown) that employ other radio technologies, such as LTE, LTE-A, LTE-A Pro, and / or non-3GPP access technologies, such as WiFi.

[0053] The SMFs 183a, 183b may be connected to the AMFs 182a, 182b in the CN 115 via an N11 interface. The SMFs 183a, 183b may also be connected to the UPFs 184a, 184b in the CN 115 via an N4 interface. The SMFs 183a, 183b may select and control the UPFs 184a, 184b and configure the routing of traffic through the UPFs 184a, 184b. The SMFs 183a, 183b may perform other functions, such as managing and assigning WTRU or UE IP addresses, managing PDU sessions, controlling policy enforcement and QoS, providing downlink data notification, etc. The PDU session type may be IP-based, non-IP-based, Ethernet-based, or the like.

[0054] The UPFs 184a, 184b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via an N3 interface, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks such as the Internet 110 to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices. The UPFs 184a, 184b may perform other functions such as routing and forwarding packets, enforcing user plane policies, supporting multi-homed PDU sessions, handling user plane QoS, buffering downlink packets, providing mobility anchoring, etc.

[0055] The CN 115 may facilitate communication with other networks. For example, the CN 115 may include or communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that acts as an interface between the CN 115 and the PSTN 108. The CN 115 may also 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 be connected to the local data networks (DNs) 185a, 185b through the UPFs 184a, 184b via an N3 interface to the UPFs 184a, 184b and an N6 interface between the UPFs 184a, 184b and the DNs 185a, 185b.

[0056] 1A-1D and the corresponding description thereof, one or more or all of the functions described herein with respect to one or more of the WTRUs 102a-d, base stations 114a-b, eNodeBs 160a-c, MME 162, SGW 164, PGW 166, gNBs 180a-c, AMFs 182a-b, UPFs 184a-b, SMFs 183a-b, DNs 185a-b, and / or any other devices described herein may be performed by one or more emulation devices (not shown). The emulation devices may be one or more devices configured to emulate one or more or all of the functions described herein. For example, the emulation devices may be used to test other devices and / or to simulate network and / or WTRU functionality.

[0057] The emulation device may be designed to implement one or more tests of other devices in a lab environment and / or in an operator network environment. For example, one or more emulation devices may perform one or more or all functions while fully or partially implemented and / or deployed as part of a wired and / or wireless communication network to test other devices in the communication network. One or more emulation devices may perform one or more or all functions while temporarily implemented / deployed as part of a wired and / or wireless communication network. The emulation device may be directly coupled to another device for testing purposes and / or may perform testing using over-the-air wireless communication.

[0058] The one or more emulation devices may perform one or more functions, inclusive, without being implemented / deployed as part of a wired and / or wireless communication network. For example, the emulation devices may be utilized in a testing laboratory and / or testing scenario in a non-deployed (e.g., testing) wired and / or wireless communication network to implement testing of one or more components. The one or more emulation devices may be test equipment. Direct RF coupling and / or wireless communication via RF circuitry (which may, for example, include one or more antennas) may be used by the emulation devices to transmit and / or receive data.

[0059] Operation in unlicensed frequency bands Operation in unlicensed frequency bands may be subject to requirements for nominal channel bandwidth (NCB) and / or occupied channel bandwidth (OCB), which may be defined for unlicensed spectrum, such as in the 5 GHz region. In some examples, the NCB may be the widest band of frequencies allocated to a single channel (including guard bands). In some example regulatory schemes, the NCB must be at least 5 MHz, and the OCB (e.g., the bandwidth that accommodates 99% of the signal's power) must be between 80% and 100% of the declared NCB. During established communications, devices may be enabled or configured to temporarily operate in a mode in which the OCB may be reduced (e.g., as low as 40% of the NCB).

[0060] In some examples, channel access in licensed or unlicensed frequency bands can use a listen-before-talk (LBT) mechanism. In aspects, LBT may be commanded regardless of whether the channel is occupied. In examples, an LBT procedure or mechanism may be defined as a mechanism by which a device applies a clear channel assessment (CCA) check before using a channel.

[0061] In a frame-based system, for example, the LBT may be characterized by any of a CCA time (e.g., ∼20 μs), a channel occupancy time (COT) (e.g., minimum 1 ms, maximum 10 ms), an idle period (e.g., minimum 5% of COT), a fixed frame period (e.g., a time period equal to COT + idle period), a short control signaling transmission time (e.g., a maximum duty cycle of 5% within a 50 ms observation period), and / or a CAA energy detection threshold.

[0062] In a load-based system, for example, LBT may be characterized by a number N corresponding to the number of one or more clear idle slots in CCA or extended CCA (ECCA) instead of a fixed frame period. In other words, LBT operation may include CCA or ECCA, which may be defined in terms of the number of slots (N slots) that need to be detected as clear and idle before the channel is considered available. In some examples, the number N may be selected randomly within a predetermined or preconfigured range. In some cases, for load-based systems, the transmit and / or receive structure may be load-based and not fixed in time.

[0063] Typical deployment scenarios may include one or more (e.g., different) standalone NR-based operations, one or more (e.g., different) variants of dual connectivity (DC) operations, and / or one or more (e.g., different) variants of carrier aggregation (CA). In one embodiment, the different variants of DC operation may include, for example, Evolved Universal Terrestrial Radio Access-New Radio-Dual Connectivity (EN-DC) with at least one carrier operating in accordance with an LTE radio access technology (RAT), or NR DC with at least two sets of one or more carriers operating in accordance with an NR RAT. In another embodiment, the different variants of CA may include, for example, different combinations of zero, one, or multiple carriers of each of the LTE or NR RAT.

[0064] In the case of an LTE system, one or more functionalities discussed herein may be considered for a licensed-assisted access (LAA) system. In a first example, LBT (e.g., clear channel assessment) may be used. CCA utilizes at least energy detection to determine the presence or absence of other signals on a channel to determine whether the channel is occupied. In some cases, European and / or Japanese regulations may mandate the use of LBT in one or more unlicensed bands. Apart from regulatory requirements, carrier sensing via LBT may be one measure for fair sharing of unlicensed spectrum and, therefore, it may be an essential feature for fair and friendly operation in unlicensed spectrum in a single global solution framework.

[0065] In some examples, in the case of LTE systems, discontinuous transmission may occur on carriers with limited maximum transmission duration. In unlicensed spectrum, channel availability may sometimes not be guaranteed. Certain regions, such as Europe and Japan, may prohibit continuous transmission in unlicensed spectrum and / or impose limits on the maximum duration of a transmission burst. Thus, in some cases, discontinuous transmission with limited maximum transmission duration may be a desired functionality for LAA.

[0066] In some examples, in the case of an LTE system, carrier selection may be configured or used. For example, an unlicensed spectrum may include a large amount of available bandwidth, and in this case, carrier selection may be configured or used to allow an LAA node to select one or more carriers with low interference and thereby achieve good coexistence with other unlicensed spectrum deployments.

[0067] WTRU operation in New Radio (NR) In NR, a WTRU may operate using a bandwidth part (BWP) on a carrier. For example, the WTRU may initially access a cell using an initial BWP. In some examples, the WTRU may be configured with a set of BWPs for proceeding with a procedure or operation. In certain representative embodiments, at any given moment, the WTRU may have one (1) active BWP. In examples, each BWP may consist of a set of CORESETs within which the WTRU can blindly decode one or more physical downlink control channel (PDCCH) candidates for scheduling and / or other processes or procedures.

[0068] NR can also support variable transmission time lengths and feedback timing. In some embodiments, with variable transmission time lengths, for example, a physical downlink shared channel (PDSCH) or physical uplink shared channel (PUSCH) transmission can occupy a contiguous subset of symbols in a slot. In some other embodiments, with variable feedback timing, the downlink control information (DCI) for the downlink assignment can include an indication of the timing of feedback for the WTRU. In an example, the indication can indicate or point to a specific physical uplink control channel (PUCCH) resource.

[0069] In some examples, NR can support two types of PUCCH resources: short PUCCH and long PUCCH. The former (short PUCCH) may be transmitted using one or two OFDM symbols, while the latter (long PUCCH) can use, for example, up to 14 OFDM symbols. Each PUCCH type can have multiple formats, which may depend on the type and / or size of the corresponding payload.

[0070] In some embodiments, NR can support a dynamic HARQ-ACK codebook, where the size of the HARQ codebook may depend on the number of scheduled transport blocks (TBs). A base station (e.g., a gNB) can use a counter downlink allocation index (DAI) and / or a total DAI in the DCI to indicate the number of previously scheduled TBs. In some examples, the counter DAI and / or the total DAI can have a size of 2 bits, allowing the WTRU to recover up to four missing or overlooked TBs. For example, in LTE and / or NR, the counter DAI is 2 bits (included in the DCI scheduling the TB) to indicate the position of the A / N bit of the TB within the HARQ-ACK codebook.

[0071] WTRU operation in unlicensed bands NR can support operation in one or more unlicensed bands in 3GPP Release 16, according to the NR Unlicensed Study Item Description. See, for example, References. Error! Reference source not found. In examples, NR-based operation in unlicensed spectrum can include initial access, scheduling / HARQ, and mobility, along with coexistence methods with LTE-LAA and other currently operating RATs. Some scenarios include an NR-based LAA cell connected to an LTE or NR anchor cell, as well as an NR-based cell operating standalone in the unlicensed spectrum.

[0072] In some examples of NR unlicensed bands, all transmissions may be preceded by a channel acquisition method (e.g., LBT). A successful LBT may be required before the WTRU can transmit control information to the gNB. Such restrictions may not apply in LTE unlicensed bands because, in LTE unlicensed spectrum, uplink control transmissions may not be supported in unlicensed bands. In LTE unlicensed, uplink control information (UCI) messages may be sent in licensed bands.

[0073] Referring to FIG. 2, in some examples, the HARQ protocol design in NR and / or LTE may not consider clear channel assessment (CCA). For example, if the gNB does not receive HARQ-ACK feedback within the configured time for feedback, the gNB may assume that the TB (e.g., scheduled in the DCI) was not received by the WTRU or that an ACK-to-DTX / NACK-to-DTX error occurred. In some cases, configuring a K1 value (e.g., a HARQ feedback timing limit) may not be suitable (e.g., for NR unlicensed operation) because it is not guaranteed that the WTRU can access the channel at the configured time. For example, with reference to FIG. 2, assume that a DCI is received in subframe 202 (subframe n) indicating a HARQ feedback timing of K1. It is also assumed that the channel is busy so that the WTRU cannot use the channel to return HARQ by subframe 204 (subframe n+K1). In this case, the gNB may assume that the WTRU did not receive the TB or that an error occurred.

[0074] Furthermore, NR uses dynamic HARQ feedback (e.g., a HARQ-ACK codebook), which allows acknowledgments of multiple TBs to be combined in one UCI transmission. In some examples, the dynamic HARQ feedback may be transmitted at the TB scheduled time and / or based on the configured time at which the HARQ-ACK feedback is sent. For the gNB to properly interpret the HARQ-ACK codebook, both the WTRU and the gNB need to be synchronized on the size (e.g., number of bits) of the HARQ-ACK codebook and the order of each HARQ ACK / NACK bit in the codebook. The NR WTRU uses the DAI to calculate the number of missed DCIs. The DAI is two bits in NR Release 15, allowing detection of up to four missed PDSCHs. If more than four PDSCHs are missed, the WTRU may not be able to report the correct HARQ-ACK codebook size. In NR unlicensed environments, it is expected to have collisions from other cells and other RATs, and therefore more than four missing PDSCHs are possible.

[0075] Representative Procedure for Shared COT for HARQ Feedback Transmission In some examples, the COT may be shared and / or used between the network (e.g., a gNB) and the WTRU. The network (e.g., a gNB) may reserve an uplink control channel or an uplink shared channel carrying the UCI for the WTRU. The WTRU may then be configured to not perform an LBT or to perform a short LBT before sending HARQ-ACK feedback, for example, based on one or more of the following conditions:

[0076] In one embodiment, an RNTI may be used to scramble the PDCCH that schedules the TBs. In an example, the WTRU may be configured with an RNTI specific to the URLLC service. Upon receiving one or more TBs scheduled by the URLLC RNTI, the WTRU may transmit HARQ feedback without performing an LBT or performing a short LBT. In another embodiment, a DCI format may be used to schedule the TBs. For example, the WTRU may be configured with a compact DCI. Upon receiving scheduling using such a DCI, the WTRU may transmit a HARQ ACK / NACK without performing an LBT.

[0077] In various embodiments, the WTRU may be configured to not perform LBT or to perform a short LBT (e.g., before transmitting HARQ feedback) based on one or more of the following conditions or indications: 1) aggregation level of the DCI scheduling the TB, 2) search space on which the DCI scheduling the TB is detected, 3) CORESET on which the DCI scheduling the TB is detected, 4) PUCCH resource indication. For example, the WTRU may be configured with a set of PUCCH resources that can be used without performing LBT. The configuration of such resources may be semi-statically configured or dynamically indicated. 5) HARQ feedback codebook size. For example, the WTRU may be configured not to perform LBT if the size of the HARQ-ACK codebook is below a threshold. 6) HARQ feedback timing. In some examples, an implicit indication from the gNB may be used. In examples, a PDSCH / PUSCH timing indication may be used. For example, if the HARQ feedback timing is K 1_thr If the number of LBTs is less than 1, then LBT is not performed, where K 1_thr is a predefined threshold for K1. In another example, the WTRU may 1_thr), the WTRU may perform an LBT (e.g., a full LBT) prior to a HARQ ACK and / or HARQ NACK transmission. 7) HARQ Process Identifier (ID). In an example, an HARQ process may be considered as a TB (e.g., stored in a buffer at the WTRU) that has not yet been delivered to a higher layer (e.g., a MAC layer). The WTRU may maintain one or more HARQ processes, each of which may be identified by a respective HARQ process ID. HARQ feedback (e.g., HARQ ACK / NACK feedback) for an HARQ process may be used to indicate the current decoding status of the TB associated with the HARQ process (e.g., a TB that has not yet been delivered to a higher layer). For example, the WTRU may be configured with a set of HARQ process IDs that may be transmitted without performing an LBT. 8) Slot Format Indication. In an example, based on semi-static or dynamic configuration using a group-common DCI, the WTRU may not perform an LBT prior to a HARQ feedback transmission. In some cases, the WTRU may not perform LBT in self-accommodated slots; and 9) explicit bit indication in the DCI.

[0078] In some examples, the HARQ-ACK transmissions may be in separate or different COTs. In an aspect, the WTRU may be configured to transmit HARQ-ACK feedback for a transport block (TB) in a next subsequent shared COT between the gNB and the WTRU. The WTRU may be configured to determine that HARQ ACK / NACK feedback may be or will be transmitted in one or more subsequent COTs. Referring to FIG. 3A , for example, based on one or more of the following embodiments or examples, the WTRU may determine that HARQ-ACK feedback for a TB received in a first COT (COT1) is transmitted in one or more subsequent COTs (e.g., COT2 and / or COT3 shown in FIG. 3A ). N ) can be transmitted.

[0079] Still referring to FIG. 3A for the HARQ transmission mechanism 300, the WTRU determines whether the HARQ-ACK feedback for a TB received in the first COT (e.g., COT1 including 10 slots each represented as slot 302) is transmitted in the next or ongoing COT (e.g., COT2 including 10 slots each represented as slot 304, and / or COT3 including 10 slots each represented as slot 306) based on a dedicated bit field in the DCI indicating the COT number, COT index, and / or COT offset in which the HARQ-ACK feedback is transmitted. N ) may be transmitted in one or more of the COT offset indications. For example, the WTRU may receive a COT offset indication in the COT (e.g., COT1) in which the DCI 310 was received. In the example shown in FIG. 3A, the WTRU receives the DCI 310 in COT1 (e.g., to schedule one or more TBs), and the DCI 310 is transmitted in one or more of the COT offset indications (e.g., in slot 306). N In some examples, the WTRU may be configured using higher layer signaling (e.g., RRC signaling) with a set of "COT offsets" (e.g., in a table or list), and the DCI bit field points to some of the configured values ​​(e.g., position in the table or list). In another embodiment, the WTRU may keep track of the COT index automatically, such as by counting the number of occurrences of a particular signal (e.g., a COT preamble) that is found only once per COT. In another example, the COT index may be determined by receiving a signal from the gNB that explicitly indicates the COT index of an ongoing COT. For example, the UE may expect a transmission (e.g., on a group common channel) at some point within the COT that provides the index of the COT.

[0080] In some embodiments, the WTRU may determine that the HARQ-ACK feedback for a TB received in the first COT (COT1) may be transmitted in one or more of the next COTs based on reusing the DCI and / or PDSCH-to-HARQ timing indicators in the DCI. Referring to FIG. 3B, tables 320 and 330 include one or more of different codepoints, PDSCH-to-HARQ timing indicators (values ​​of K1, K2, K3, and K4), and units (e.g., slots, COTs, or COTs and slots). In an example, as shown in table 320 of FIG. 3B, a subset of the PDSCH-to-HARQ timing indicators may be configured in units of slots, and another subset of the PDSCH-to-HARQ timing indicators may be configured in units of "gNB starting COT." In another example, a set of PDSCH-to-HARQ timing (eg, in a PDSCH-to-HARQ timing indicator) may indicate a COT offset and a slot within the COT, as shown in table 330 of FIG. 3B.

[0081] In some embodiments, the WTRU may determine that the HARQ-ACK feedback for the TB received in the first COT (COT1) may be transmitted in one or more of the next COTs based on the reused PDSCH time domain resource allocation and the PDSCH-to-HARQ timing indicator in the DCI. For example, the PDSCH time domain resource allocation in the last slot or slots of the COT (e.g., the last X slots) and the K 1_thrUpon receiving a PDSCH-to-HARQ timing indicating a value greater than X, the WTRU may determine that HARQ feedback (e.g., HARQ ACK / NACK feedback) will be transmitted in the next gNB starting COT. In an example, the WTRU may apply the PDSCH-to-HARQ timing from the starting slot of the next or future COT. For example, the WTRU may receive a PDSCH-to-HARQ timing value of 4 slots. The WTRU may transmit HARQ feedback 4 slots after the start of the next COT. In another example, the WTRU may be configured to transmit HARQ feedback in the next COT in a slot having a slot number equal to the sum of the K0 values ​​in the PDSCH time domain resource allocation and the PDSCH-to-HARQ timing indicator. In some instances, X and K 1_thr The value of may be configured using higher layer signaling (e.g., SIB / RRC-specific signaling) or may be fixed in a standard. In an example, the WTRU may receive a PDSCH-to-HARQ timing value that indicates a COT index (e.g., an index including one or more offsets from the COT used for the PDSCH) and one or more slots within the COT for HARQ feedback transmission.

[0082] In some embodiments, the WTRU may determine, based at least on the search spaces and / or CORESETs used for DCI transmission, that HARQ-ACK feedback for TBs received in the first COT (COT1) may be transmitted in one or more of the next COTs. For example, the WTRU may be configured with a set of search spaces and / or CORESETs at which HARQ feedback associated with TBs scheduled by those search space sets and / or CORESETs may be sent in the next COT. The WTRU may be configured to transmit the HARQ feedback at a slot number indicated by a PDSCH-to-HARQ timing indicator in the next COT or at a slot number equal to the sum of the K0 values ​​in the PDSCH time domain resource allocation and the PDSCH-to-HARQ timing indicator in the next COT.

[0083] In an example, the COT may be configured by the network (e.g., gNB) with a fixed length of time for the WTRU (as shown in FIG. 3A, the COT has a length of time of 10 slots). In another example, the COT length of time may vary from one channel occupancy period to another. In some examples, the WTRU may be configured to determine the length of time of the or each COT based on one or more of the following factors:

[0084] In some embodiments, the WTRU may be configured to determine the duration of one or each COT based on a slot format indication. For example, the WTRU may be configured to receive a slot format indication at the beginning of each COT. Based on the slot format indicated in the slot format indication, the WTRU can determine the number of slots and / or symbols allocated to the DL, flexibly, and UL, and determine the current COT duration. Furthermore, the WTRU may be configured with a mapping rule or index between the slot format and the COT duration.

[0085] In some embodiments, the WTRU may be configured to determine the duration of one or each COT based on a search space periodicity configuration. For example, the WTRU may be configured to determine the COT duration based on a search space periodicity and / or duration configuration. In one implementation, the WTRU may determine the COT duration based on a maximum periodicity and / or duration of a configured search space set.

[0086] In some embodiments, the WTRU may be configured to determine the time length of one or each COT based on one or more preamble transmissions. For example, the WTRU may be configured to monitor a set of preambles having different sequences and / or lengths. Upon detecting a preamble with a unique sequence or length, the WTRU can determine the time length of the gNB-initiated COT. In some instances, the WTRU may be configured with a mapping rule or index between the COT time length and the preamble.

[0087] Representative procedure for combining HARQ-ACK feedback from multiple TBs In some examples of HARQ-ACK codebook determination, the WTRU may be configured to transmit ACK / NACK (A / N) feedback for all received TBs prior to the feedback transmission time in one HARQ-ACK codebook. The WTRU may transmit additional information along with the HARQ-ACK codebook to indicate the HARQ process ID and / or the number of HARQ process IDs carried by the codebook. In some cases, the number of HARQ process IDs may be equal to the number of acknowledged TBs (or the number of received TBs). In some embodiments, the additional information may include any of the following: 1) the reception time of the first acknowledged TB in the codebook, e.g., the slot number and / or subframe number of the first A / N in the codebook, 2) the reception time of the last acknowledged TB in the codebook, 3) the number of acknowledged TBs in the HARQ feedback, and 4) an indication of the HARQ process ID sent in the HARQ-ACK feedback. For example, the WTRU may be configured with a set of HARQ process IDs that may be transmitted within the HARQ-ACK codebook. In an example, 8 of the 16 HARQ process IDs may be transmitted in one codebook, while the remaining 8 HARQ process IDs may be transmitted in a different HARQ codebook. In some cases, the HARQ process IDs identify the HARQ processes. Alternatively, the WTRU may transmit a bitmap indicating a subset of the HARQ process IDs transmitted in the feedback.

[0088] In some embodiments, the WTRU may be configured to exclude A / N feedback for TBs received in a preconfigured time window prior to the HARQ codebook transmission. For example, the WTRU may not be able to process TBs received in the last subframe prior to the HARQ feedback transmission, and therefore does not transmit the A / N for the last TB.

[0089] In some embodiments, the WTRU may be configured with a counter DAI and / or a total DAI to determine the number of scheduled TBs and the sequence of A / N bits in the HARQ-ACK codebook. When the WTRU detects a missing DCI, it may transmit a HARQ-ACK codebook with only the TBs received prior to the false detection time. For example, as shown in FIG. 4, the WTRU receives two DCIs scheduling a first TB in subframe 402 (e.g., subframe n) and a second TB in subframe 404 (e.g., subframe n+3) with counter DAIs c=0 and c=1, respectively. The WTRU receives a DCI in subframe 408 (e.g., subframe n+10) scheduling a TB with counter DAI c=3. The WTRU determines that at least one DCI is missing and reports HARQ-ACK feedback for only the TBs in subframe 402 and the TBs in subframe 404 (TB1 and TB2). In the example, the missed DCI schedules a TB in subframe 406 (eg, subframe n+6).

[0090] In the case of HARQ ACK codebook accumulation, in some examples, the WTRU may not obtain a channel for transmitting HARQ-ACK feedback for one or a set of TBs. In this case, the WTRU may transmit HARQ-ACK feedback for that codebook in a future HARQ-ACK feedback resource. Between the time between the failed HARQ-ACK feedback resource and the future resource, the WTRU may be scheduled for a further PDSCH transmission. The WTRU may combine HARQ-ACK bits for the previous, non-feedbacked TBs with HARQ ACK bits for the new TBs in the new codebook. In an example, the two sets of bits may be addressed as two separate codebooks (e.g., coded separately) in the same feedback report. In another example, the two sets of bits may be considered as a single, larger codebook. The WTRU may provide an indication in the feedback report of the total number of codebooks included in the report (or the total number of TB sets included in the report, or the number of combined HARQ-ACK feedback report sets included in the report).

[0091] In some examples, the WTRU may be provided with a periodic HARQ-ACK feedback resource. The WTRU may use the periodic HARQ-ACK feedback resource to transmit a set of feedback bits for a set of TBs for which the WTRU has not yet transmitted feedback. The codebook size may increase with each failed channel access to report feedback. The WTRU may use such a periodic HARQ-ACK resource as a fallback if it fails to transmit a HARQ-ACK in the dynamically indicated HARQ-ACK feedback resource.

[0092] The accumulation may be for feedback of TBs transmitted on different unlicensed channels (where an unlicensed channel is defined as a portion of an unlicensed carrier that may be acquired in the LBT process). For example, a WTRU may receive multiple TBs on a first unlicensed channel and may be expected to feedback HARQ-ACKs on the same channel. However, the WTRU may not be able to acquire a channel for HARQ-ACK feedback. The WTRU may then be scheduled on a second unlicensed channel and may report feedback on that second channel. The feedback report on the second unlicensed channel may include accumulated feedback for both the first and second sets of TBs (received by the WTRU on the first and second unlicensed channels, respectively).

[0093] In some embodiments, the WTRU may be configured with a time period t1 during which A / N feedback for the TB should be sent to the network. Time period t1 may be defined as an offset from the time the TB was received or as an offset from the time the DCI scheduling the TB was received. Such a time period may be configured semi-statically or dynamically.

[0094] Alternatively, the WTRU may select a set of times for possible HARQ-ACK transmissions {k1,1,k1,2,...k1, N For example, the WTRU may receive DCI scheduling a TB in subframe n, and the HARQ-ACK feedback for that TB may be sent in subframes n+k1,1,n+k1,2,...n+k1, N The set of times may be configured semi-statically or dynamically.

[0095] In another embodiment, the WTRU may be configured with timing and a timer for HARQ-ACK transmission. For example, the WTRU may start a timer if it fails to transmit HARQ-ACK feedback at the configured time. When the timer expires, the WTRU attempts to retransmit the HARQ-ACK feedback. The values ​​for the time and timer for transmitting HARQ-ACK feedback may be configured using higher layer signaling or may be indicated dynamically. While the timer is running, the WTRU may receive timing updates from the network. In another embodiment using a timer, the WTRU may attempt to send the HARQ-ACK while the configured timer is running. When the timer expires, the WTRU may monitor the PDCCH for retransmission or a HARQ-ACK trigger signal from the gNB prior to sending the HARQ-ACK. The WTRU may further adjust or add a value to the timer. For example, the WTRU may extend the timer if it determines that the channel was busy or occupied by the serving cell.

[0096] In some examples, triggers for transmitting the HARQ-ACK codebook may be used. The WTRU may be configured to transmit HARQ-ACK feedback in response to (e.g., upon receiving or identifying) one or more of the triggers. The one or more triggers may include a number of received PDSCHs above a threshold. For example, the WTRU may be configured to transmit HARQ-ACK feedback for all received PDSCHs after receiving N PDSCHs. The one or more triggers may be N slots and / or K slots. N Symbols and N' slots and / or K' NThe one or more triggers may include a determination that up to M symbols have been transmitted or received. The one or more triggers may include a number of downlink-to-uplink switching points. For example, the WTRU may be configured to transmit a HARQ-ACK after M=1 switching points, e.g., every time there is a downlink-to-uplink switch. In some cases, the one or more triggers may include a determination that downlink control signaling indicating a set of HARQ processes has been received. The one or more triggers may include a determination that a failure in transmission of a HARQ-ACK codebook on a previous HARQ-ACK resource has occurred. For example, the failure in transmission of a HARQ-ACK codebook may be that the WTRU was unable to acquire a channel on a previous HARQ-ACK resource. In another example, the WTRU may accumulate more than a threshold number of feedback bits in previous HARQ-ACK resources (e.g., due to one or more previously unsuccessful channel accesses for feedback reporting), and since the WTRU cannot transmit the HARQ-ACK codebook in one HARQ-ACK resource, the WTRU segments the feedback report into multiple reports to be each transmitted on a different HARQ-ACK resource.

[0097] In various embodiments, the WTRU may store or maintain feedback values ​​for an HARQ process. For example, the WTRU may further store or maintain feedback values ​​for an HARQ process after receiving a New Data Instance (NDI) for the corresponding HARQ process. The WTRU may provide aggregated feedback for several TBs already transmitted with the same HARQ process ID, possibly upon receiving a trigger to transmit an HARQ-ACK from the network.

[0098] Representative Procedure for Retransmission of HARQ-ACK Information In some embodiments, the WTRU may transmit HARQ-ACK information originally scheduled to be included on a first resource (PUCCH or PUSCH) and in a first time instance on a second resource (PUCCH or PUSCH) and in a second time instance. Such a solution may be useful if the transmission on the first resource and time instance could not occur due to an LBT failure. More broadly, the solution may also be useful whenever the network detects that HARQ-ACK information for a specific instance was not successfully received.

[0099] To support retransmission of HARQ-ACK information, the WTRU may associate a codebook process (or codebook process identity) with a set of HARQ-ACK feedback bits corresponding to a set of downlink transmissions. In an example, a codebook process may be a set of HARQ-ACK feedback for one or more HARQ processes, with each HARQ-ACK feedback associated with at least one bit per TB. The WTRU may retain the set of HARQ-ACK bits of a codebook process in memory until it generates a new set of HARQ-ACK bits for the same codebook process, or possibly for a different set of downlink transmissions. The WTRU may be scheduled to include the HARQ-ACK bits of at least one codebook process in resources. Solutions to facilitate the above steps are described below. The number of codebook processes may be predetermined or configured by higher layers.

[0100] Some examples for determining the codebook process for the HARQ-ACK of a DL transmission are provided herein: When generating a HARQ-ACK for a DL transmission, for example, the WTRU may obtain the corresponding codebook process based on at least one of the following solutions:

[0101] In an example, the codebook process may be explicitly identified in the DCI scheduling the DL transmission using a new or existing field. For example, each codepoint of the PUCCH resource indicator field or of the PDSCH-to-HARQ feedback timing indicator field may be associated with a unique process index in addition to other information as per the existing interpretation of the field.

[0102] In various embodiments, the codebook process may be implicitly identified by any of the following characteristics of the DL transmission: 1) the timing of the DL transmission, e.g., in terms of subframe number, slot number, or symbol index when the transmission starts or stops, 2) the bandwidth part (BWP) index, 3) the carrier or serving cell index, and 4) possibly the timing of the UL transmission (or resource) in which the HARQ-ACK will be included, based on information included in the DCI of the DL transmission. Such timing may be in terms of any of the subframe number, slot number, and / or symbol index.

[0103] In one embodiment, one or more codebook processes may be identified by a transmission profile or set of parameters associated with the DL transmission. Each DL transmission may be associated with or parameterized by a transmission profile. The transmission profile may be determined by or may indicate any of a priority requirement, a latency requirement, a block error rate (BLER) requirement, a transmit power requirement, a redundancy requirement, a repetition requirement, and an LBT category requirement. In an example, a WTRU may maintain multiple different codebook processes, each associated with a respective transmission profile (e.g., associated with a service type such as eMBB or URLLC). In some cases, different variants, each with a different transmission profile (and a different corresponding codebook process), may be used for URLLC. In another embodiment, one or more codebook processes may be identified by a parameter of the DL transmission, such as the priority of the DL transmission. For example, the WTRU may determine the priority based on the parameter of the DL transmission. In another example, the priority may be determined based on a priority indication in the DCI that schedules the DL transmission.

[0104] The codebook process may be implicitly identified based on the UL resource and / or time instance in which the HARQ-ACK will be included. For example, the WTRU may maintain a current codebook process index and rotate the process index (e.g., increment modulo the number of codebook processes) when a new time instance and / or resource is indicated for transmission of the HARQ-ACK. In some cases, the current process index is incremented only if a field in the DCI indicating the new time instance and / or resource is set to a unique value. For example, a new field "HARQ-ACK retransmission" may be included in the DCI, and the WTRU will increment the codebook process only if such field is set to zero.

[0105] In one embodiment, the codebook process index may be determined as a function of the indicated PUCCH resource index. In another embodiment, the codebook process index may be determined as a function of the transmission profile and / or priority associated with each DL transmission. For example, different sets of codebook process indexes may be reserved for transmissions of different priorities. When a WTRU is scheduled for a DL transmission of a specific priority and determines that a new codebook process index is required, the WTRU may use the lowest (or highest) available index value for the transmission with the specific priority. In another example, when the WTRU is asked to build a new codebook process for data with a higher priority, it may shift all of the codebook process index values ​​of existing codebook processes.

[0106] In some examples, the codebook process of the HARQ-ACK transmitted on the resource may be identified or determined. When transmitting HARQ-ACK information on a PUCCH or PUSCH resource, the WTRU may include at least one codebook process of the HARQ-ACK for at least one of the following solutions:

[0107] In an example, the set of codebook processes may be explicitly indicated in the DCI indicating the resource. For example, a field in the DCI indicating the PUCCH resource may indicate the index of the codebook process in which the HARQ-ACK information will be included. Such a field may correspond to an existing field such as a PUCCH resource indicator, or a newly defined field.

[0108] Such an indication may be an absolute index or may be relative to the current process index. For example, a value of zero (0) may correspond to the current process index, a value of one (1) may correspond to the previous process index (C-1) modulo the number of processes, etc. In another example, each codepoint in the field may indicate a subset of codebook processes based on a predefined mapping or based on higher layer signaling. For example, if two codebook processes are configured, the first codepoint may correspond to the current process index, the second codepoint may correspond to both processes, the third codepoint may correspond to the previous process index, and the fourth codepoint may correspond to neither process. In the latter case, no HARQ-ACK information may be included and no PUCCH transmission may be performed.

[0109] In another example, a field in the DCI may indicate the number of processes, N, for which HARQ-ACK information will be included. In this case, the set of processes may correspond to {C-N+1, C-N+2, ..., C} (modulo the number of processes), where C is the current process index.

[0110] In an example, the codebook process may be implicitly indicated in the DCI indicating the resource. For example, if the DCI corresponds to a DL allocation, the codebook process for the corresponding HARQ-ACK (e.g., determined using the solution described in the paragraph above) may be implicitly indicated by the specific resource assigned in the HARQ-ACK feedback. In some cases, the HARQ-ACK bits to be included in the resource may include one or more HARQ-ACK bits for the DL allocation indicated by the DCI. In this case, it may not be necessary to explicitly indicate the codebook process using a separate field in the DCI.

[0111] In cases where a PUCCH resource is indicated by more than one DCI, the codebook process to be included may correspond to the last received DCI.

[0112] In one embodiment, the set of codebook processes may depend on the DCI format. For example, a new DCI format may be defined that accommodates an indication of PUCCH resources without DL allocation. When this DCI format is received, the WTRU may include HARQ-ACK for the set of codebook processes explicitly indicated in such format. In cases where the DCI format indicates that a DL transmission is being received, the WTRU may include HARQ-ACK information for the codebook processes corresponding to the DL transmission.

[0113] In one embodiment, the WTRU may include at least one codebook process index in a PUCCH or PUSCH resource to indicate the set of codebook processes for which the HARQ-ACK is included in the resource. This solution may be used, for example, when there is no DCI to dynamically schedule resources.

[0114] In some embodiments, the WTRU may be configured to adjust codebook process bits based on a single HARQ feedback request received from the network (e.g., gNB). Single HARQ feedback may be defined as the WTRU transmitting all ACK / NACK bits (or a set / group of ACK / NACK bits) upon receiving a request from the network. The WTRU may be configured to simultaneously support the codebook process feature as well as the single HARQ feedback feature. The WTRU then groups multiple HARQ feedbacks over codebook processes in addition to monitoring the single HARQ feedback request. In an example, the WTRU may be configured to erase all codebook processes after transmitting the single HARQ feedback. In another example, the WTRU may be configured to remove ACK / NACK bits of codebook processes corresponding to TBs received X ms (or more) prior to transmitting the single HARQ feedback. In an example, the WTRU may be configured (e.g., based on an indication from the network) to remove, e.g., exclusively remove, from the codebook process, ACK / NACKs for TBs that were part of a one-off HARQ feedback (e.g., a one-off HARQ feedback transmitted after a successful LBT). Alternatively, the WTRU may be configured to retain the ACK / NACK bits in the codebook process regardless of whether a one-off HARQ feedback was transmitted or not.

[0115] Representative procedure for HARQ-ACK resource determination 5 and 6, in some examples, multiple HARQ-ACK feedback resources may be used or configured. To address reduced HARQ A / N transmission opportunities, the WTRU may be provided with multiple PUCCH resources for HARQ-ACK transmission. The WTRU may be configured to select one PUCCH resource from the multiple PUCCH resources based on one or more of the following:

[0116] A first example is the result of an LBT. For example, the WTRU may determine a PUCCH resource based on the success or failure of the LBT. Referring to FIG. 5, in an example, the WTRU may be configured with multiple PUCCH resource sets (e.g., PUCCH resource set 502, PUCCH resource set 504, and PUCCH resource set 506), where each resource set is applicable to the nth channel access attempt. For example, when first attempting to transmit HARQ feedback, the WTRU selects the first PUCCH resource set 502, and based on an acknowledgement resource indicator (ARI) in the DCI 508, the WTRU determines a resource within the resource set 502. In some cases, if the WTRU fails to access the channel in the selected resource, the WTRU may select a resource from the second PUCCH resource set 504 based on the ARI (e.g., in the DCI 510). 6, when selecting from the PUCCH resource set 602, the WTRU may be configured with an offset (e.g., in the DCI 604) to be added to the ARI (e.g., received in the DCI 606 and / or DCI 604). The offset and / or PUCCH resource set configuration in case of an LBT failure may be semi-statically configured or dynamically indicated. For example, after failing to send HARQ feedback (e.g., based on the ARI in the DCI 606), the WTRU may receive an offset indication or a resource set indication in the DCI (e.g., the DCI 604).

[0117] A second example is randomization. For example, the WTRU may be configured to randomly select a resource from a PUCCH resource set. In such a case, the network may not know which WTRU is sending feedback. To solve this problem, the WTRU may be configured to indicate the identity of the WTRU to the network along with the feedback. For example, the WTRU may attach a cyclic redundancy check (CRC) scrambled with the Cell RNTI (C-RNTI) to the HARQ-ACK codebook.

[0118] A third example is a DCI false detection. For example, the WTRU may select UCI resources based on whether DCI is not found. For example, the WTRU may be configured to transmit HARQ-ACK feedback only for TBs prior to the DCI false detection. In such a case, the WTRU may use a different PUCCH resource set and / or different resources within the PUCCH resource set for HARQ-ACK compared to when it correctly detects DCI.

[0119] A fourth example is upon reception of a PUCCH trigger signal, which may be based on receiving a PDCCH, for example, and which may further indicate to the WTRU the availability of certain PUCCH resources, possibly with or without certain LBT requirements.

[0120] In various embodiments, the WTRU may be configured to transmit HARQ feedback on PUSCH resources. For example, the WTRU may include the HARQ-ACK codebook from the failed PUCCH transmission in the next PUSCH opportunity. For example, the HARQ-ACK feedback may be configured to be transmitted in slot n. After performing the LBT, the WTRU fails to access the uplink control channel. The WTRU may send the HARQ-ACK feedback using the next uplink grant. In order for the gNB to correctly decode the PUSCH carrying UCI and data, the WTRU may be configured to use the PUSCH grant for HARQ-ACK transmissions only after the first failed HARQ-ACK transmission and until a configured time. Such time may be configured using an offset from the first HARQ-ACK transmission opportunity. Alternatively, the WTRU may be configured to use only the PUSCH within the configured time for HARQ-ACK transmission. For example, the WTRU may select a set of timings for possible HARQ-ACK transmissions {k1,1,k1,2,...k1, N}, the WTRU is allowed to use only the PUSCH during those same times.

[0121] Exemplary Procedure for HARQ Feedback for Uplink Transmission The WTRU may monitor for one or more DL HARQ-ACK feedbacks, and the WTRU may be configured to monitor a physical downlink channel to receive downlink HARQ-ACK feedback for uplink transmissions. The physical downlink channel may be in configured predefined time and frequency resources. Alternatively, the WTRU may be configured to monitor DCI within multiple time and frequency locations to receive downlink HARQ-ACK feedback. For example, the WTRU may be configured to monitor a large number of DCI candidates across multiple CORESETs / search space sets, and based on the gNB channel occupancy duration, the WTRU prioritizes a subset of the CORESETs / search space sets to be monitored. In some examples, the WTRU may prioritize a CORESET / search space based on one or more of the following: In one embodiment, the WTRU may prioritize a CORESET / search space based on the CORESET / search space set ID. For example, the WTRU may be configured to prioritize a search space with index "0" for downlink HARQ feedback monitoring. In another embodiment, the WTRU may prioritize a CORESET / search space based on the CORESET / search space set in which the last DCI was received, for example, the WTRU may prioritize monitoring the CORESET in which the TB in which the DCI was last received was scheduled.

[0122] In one example, a WTRU may be configured with multiple BWPs, where only one BWP of the multiple BWPs is active at any given time. The WTRU may switch its active BWP or monitor all configured BWPs if downlink feedback is not received within a preconfigured time. In another example, a WTRU may be configured with multiple CORESETs and may monitor only a subset of the CORESETs configured for HARQ feedback. However, if downlink feedback is not received on that subset of CORESETs within a preconfigured time, the WTRU monitors all CORESETs.

[0123] The WTRU may be configured to receive the DL HARQ-ACK using the group-common PDCCH. The WTRU may be configured with the group ID to be scrambled with the DCI carrying the group-common PDCCH. Alternatively, the WTRU may determine the group ID based on the HARQ process ID for which it expects to receive an acknowledgment. For example, the WTRU is configured with a maximum HARQ process equal to 16. The WTRU expects acknowledgments for HARQ processes 0, 4, and 10 in a given slot. In some instances, the WTRU then monitors the group-common DCI scrambled with 1000100000100000.

[0124] Representative Procedures for UL HARQ Operation and Scheduling In some examples, multiple PUSCH opportunities may be provided by a single scheduling DCI. The WTRU may receive multiple grants for a single HARQ process ID using a single PDSCH scheduling DCI, possibly with disjoint PUSCH transmission time lengths. Upon receiving such a grant, the WTRU may attempt to transmit a TB on the first granted PUSCH opportunity. If the LBT fails, the WTRU may attempt to transmit a PUSCH on the next granted PUSCH opportunity, and may further repeat such actions until the LBT is successful and a TB is transmitted.

[0125] Upon successfully transmitting a TB in a PUSCH grant within the sequence of PUSCH grants provided for a single HARQ process, the WTRU may ignore the remaining PUSCH opportunities in the sequence of PUSCH grants provided. Alternatively, for example, upon successfully transmitting a TB in a PUSCH grant within the sequence of PUSCH grants provided, the WTRU may attempt to transmit another TB. Such attempts may depend on network configuration or on receiving control signaling from the network. For example, upon successfully transmitting a TB in a PUSCH grant within the sequence of PUSCH grants provided, the WTRU may attempt to transmit another TB in the next granted PUSCH opportunity if it receives a new data indicator (NDI) or if the WTRU receives an ACK for a previous TB transmitted in the same HARQ process.

[0126] In some examples, when a WTRU transmits different TBs on different PUSCH occasions using a single grant, the WTRU may determine the HARQ ID associated with each TB based on one or more of the following embodiments: In some cases, a pool or set of HARQ process IDs (PIDs) may be dynamically indicated, for example, based on one or more embodiments discussed below.

[0127] In some embodiments, the WTRU may determine the HARQ ID associated with each TB based on a selection from a pool or set of HARQ IDs signaled by L1 signaling (e.g., part of the HARQ information in the DCI). For example, the DCI may indicate a pool / set of HARQ PIDs mapped to each TTI in succession, or a PUSCH duration that may be used, and the WTRU may select one or more HARQ PIDs in the order of the TTIs selected for transmission. In another example, the WTRU may select a HARQ PID from the pool randomly or according to a pattern configured by higher layers (e.g., a pre-configured pattern).

[0128] In some embodiments, the WTRU may determine the HARQ ID associated with each TB based on a formula. In some instances, the WTRU may use a formula to determine the HARQ process ID, i.e., PID. For example, the HARQ process ID may be a function of at least one of the selected PUSCH duration, the indicated HARQ process ID pool / set, the current slot or minislot, and / or the subframe / frame timing.

[0129] In some embodiments, the WTRU may determine the HARQ ID associated with each TB based on one or more selected TTIs / PUSCH opportunities. For example, the WTRU may be assigned a single HARQ process ID in the HARQ information, and the WTRU may use an increment of the indicated HARQ process ID based on the time delta between the selected PUSCH opportunity and the first PUSCH opportunity indicated for the grant (or, equivalently, based on the time delta between the selected PUSCH opportunity and the TTI during which the DCI was received). In an example, if DCI is received in slot x and the indicated HARQ process is y, the WTRU may select HARQ process y+3 when PUSCH is transmitted in slot x+3.

[0130] In some embodiments, the WTRU may further select a HARQ process ID for the new TB transmission by avoiding HARQ process IDs already in use for different TBs, e.g., HARQ process IDs used for TBs for which NDI is not toggled or for which no acknowledgement has been indicated. In some cases, for any of the HARQ process ID selection methods mentioned above, the WTRU may skip one or more (or all) HARQ process IDs that are still in use for retransmissions.

[0131] In an example, after a WTRU receives a grant intended for multi-TTI scheduling, the WTRU may attempt an LBT on each possible PUSCH opportunity until a transmission can occur or the channel is acquired.

[0132] In another example, after a WTRU receives a grant intended for multi-TTI scheduling, the WTRU may attempt a single LBT for a set of consecutive PUSCH durations (e.g., a set of uninterrupted PUSCH durations). For example, the WTRU may apply a single LBT for a set of consecutive TTIs without any gaps in between (e.g., no gaps between any two consecutive TTIs of the set of TTIs). If the LBT is successful and the channel is acquired during the first TTI, the WTRU may transmit PUSCH in adjacent TTIs without seeking further LBT. On the other hand, if the LBT determines that the channel is busy prior to the first TTI, the WTRU may perform an LBT prior to the second TTI. In some cases, if the second LBT is successful, all upcoming adjacent TTIs may not require an LBT. On the other hand, if the second LBT determines that the channel is busy, the subsequent TTI may require an LBT in a similar manner prior to transmission in the subsequent TTI.

[0133] In an example, after a WTRU receives a grant intended for multi-TTI scheduling, the WTRU may attempt a single LBT during a set of consecutive TTIs such that the transmission time length of the set is not greater than the transmission time length applicable to the LBT type.

[0134] In some examples, after a WTRU receives a grant intended for multi-TTI scheduling, where the indicated HARQ process is already in use for a previous TB (e.g., a HARQ PID with NDI not toggled), and the grant indicates multi-TTI scheduling, the WTRU may attempt to retransmit the TB associated with the indicated HARQ process ID. Once the WTRU retransmits the TB and the remaining PUSCH opportunities are valid for the scheduled grant, the WTRU may transmit another TB using a different HARQ process ID (e.g., using a HARQ PID selected per any of the methods mentioned above for HARQ PID selection). Alternatively, the WTRU may retransmit the same TB in a different successive TTI that is valid for the grant, but with a different RV and / or using the same HARQ process ID. In some cases, this may further depend on the content of the DCI.

[0135] In various embodiments, the WTRU may determine one or more timer values ​​based on the timing of receipt of a HARQ feedback trigger. In an example, the WTRU may receive control information (e.g., DCI) for one or more downlink transmissions. The control information may indicate to the WTRU that the WTRU may be triggered to report HARQ feedback at a later time. In such a case, the WTRU may suspend some or all activity-based timers (e.g., until receipt of a trigger for HARQ feedback). In some examples, the activity-based timers may include at least one of a timer for determining when to proceed to discontinuous reception (DRX), a timer for determining when to switch BWPs (e.g., switching to a default BWP), and a timer for determining when to deactivate an SCell. In an example, the WTRU may suspend one or more activity-based timers until receipt of a HARQ feedback trigger signal. In another example, the WTRU may suspend one or more activity-based timers until the timing of the arrival of a triggered HARQ feedback transmission. In another example, the WTRU may pause one or more activity-based timers (e.g., paused from the moment it receives a DCI scheduling a DL transmission) until successful completion of such scheduled transmission. For example, if the WTRU has received a DCI for a PDSCH and the WTRU expects a second DCI for HARQ feedback, the WTRU may pause one or more timers at least until successful transmission of the HARQ feedback. In some cases, the WTRU may be configured with more than one resource for transmitting HARQ feedback and may transmit exclusively on the earliest resource for which the LBT is successful.

[0136] In various embodiments, the WTRU may have multiple timer values ​​or sets of timer values ​​to be used for HARQ feedback. In some examples, the WTRU may determine or select a timer value (or set of timer values) based on whether HARQ feedback is indicated in a PDSCH scheduling DCI or whether HARQ feedback is triggered in a later DCI. For example, if the HARQ feedback transmission resource is indicated in the PDSCH scheduling DCI, the WTRU may use a first value (or a first set of values), and if the HARQ feedback transmission resource is expected in a future DCI, the WTRU may use a second value (or a second set of values). In such examples, the timer may be triggered upon reception of the scheduling DCI, e.g., regardless of the timing of the HARQ feedback resource.

[0137] Upon expiration of one or more activity-based timers, the WTRU may take action prior to the time scheduled for HARQ feedback transmission. For example, an inactivity timer (e.g., a BWP inactivity timer) may expire between the time period between the reception of a PUSCH and the reception of a HARQ feedback trigger. In such a case, the WTRU may switch the BWP to a default BWP. The WTRU may maintain the HARQ feedback bits or values ​​and, e.g., may expect to receive a HARQ feedback transmission trigger in a new BWP due to a PDSCH transmission in the previously used BWP. When the first timer expires and the WTRU takes action, the WTRU may reset or maintain other activity-based timers. For example, the WTRU may switch to the default BWP due to the expiration of a deactivation timer.

[0138] In one embodiment, the WTRU may maintain one or more other timers (e.g., a DRX timer and / or an SCell deactivation timer). The timers used for other WTRU behavior may be modified or configured to ignore the fact that a HARQ transmission feedback trigger has not been received by the WTRU. In another embodiment, the timers maintained for other WTRU behavior may be maintained from behavior determined in a previous WTRU state (e.g., a previous BWP) and may therefore depend on knowledge or lack of knowledge of HARQ feedback transmission resources.

[0139] In various embodiments, the WTRU may be triggered to report feedback on one or more BWP and / or LBT subbands. For example, the scheduling DCI and / or HARQ feedback triggering DCI may indicate a set of resources on multiple BWP and / or LBT subbands. This may improve channel access probability. Upon successful transmission on at least one resource, the WTRU may be configured to ignore all other HARQ feedback transmission resources indicated for those HARQ processes and scheduled prior to the transmission of the HARQ feedback. For example, the WTRU may be rescheduled to transmit HARQ feedback for HARQ processes for which it previously transmitted HARQ feedback. If a second request occurs after the original transmission of the HARQ feedback, the WTRU may not ignore it.

[0140] In various embodiments, the WTRU may retain all information regarding the HARQ feedback at least until successful transmission of the HARQ feedback. For example, the WTRU may be granted resources for HARQ feedback, but the WTRU may not successfully acquire a channel for transmission on such resources. In such a case, the WTRU may retain the HARQ feedback information, assuming that it may be triggered in the future on a new HARQ feedback transmission resource for such HARQ process.

[0141] References Each of the following references is incorporated herein by reference: (1) Non-Patent Document 1, (2) Non-Patent Document 2, (3) Non-Patent Document 3, (4) Non-Patent Document 4.

[0142] Conclusion While features and elements are described above in particular combinations, those skilled in the art will recognize that each feature or element may be used alone or in any combination with the other features and elements. The methods described herein may be implemented in a computer program, software, or firmware embodied in a computer-readable medium for execution by a computer or processor. Examples of non-transitory computer-readable storage media include, but are not limited to, ROM, RAM, registers, cache memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magneto-optical media, and optical media such as CD-ROM disks and digital versatile disks (DVDs). A processor in association with software may be used to implement a radio frequency transceiver for use in the WTRU 102, UE, terminal, base station, RNC, or any host computer.

[0143] Moreover, in the embodiments described above, processing platforms, computing systems, controllers, and other devices containing processors are described. These devices may contain at least one central processing unit ("CPU") and memory. In accordance with the practices of those skilled in the art of computer programming, references to acts and symbolic representations of operations or instructions may be performed by various CPUs and memories. Such acts and operations or instructions may be referred to as being "executed," "computer-executed," or "CPU-executed."

[0144] Those skilled in the art will recognize that the acts and symbolically represented operations or instructions include the manipulation of electrical signals by a CPU. The electrical system represents the data bits, which can result in the resulting transformation or reduction of the electrical signals and the maintenance of the data bits in memory locations in a memory system, thereby reconfiguring or otherwise altering the operation of the CPU and other processing of the signals. The memory locations in which the data bits are maintained are physical locations that have particular electrical, magnetic, optical, or organic properties that correspond to or represent the data bits. It should be understood that exemplary embodiments are not limited to the platforms or CPUs described above, and that other platforms and CPUs can support the provided methods.

[0145] The data bits may also be maintained on computer-readable media, including magnetic disks, optical disks, and any other volatile (e.g., RAM) or non-volatile (e.g., ROM) mass storage systems readable by a CPU. The computer-readable media may include computer-readable media that reside exclusively on a processing system, or that are distributed among, cooperating with, or interconnected to multiple interconnected processing systems, which may be local or remote to the processing system. It will be understood that exemplary embodiments are not limited to the memories described above, and that other platforms and memories may support the described methods.

[0146] In illustrative embodiments, any of the operations, processes, etc. described herein may be implemented as computer-readable instructions stored on a computer-readable medium. The computer-readable instructions may be executed by a processor of a mobile unit, a network element, and / or any other computing device.

[0147] Little distinction remains between hardware and software implementations of aspects of a system. The use of hardware or software is generally (e.g., in that, although not always, in certain contexts, the preference between hardware and software may be significant) a design preference expressing a cost versus efficiency tradeoff. There may be a variety of vehicles (e.g., hardware, software, and / or firmware) in which the processes and / or systems and / or other technologies described herein may be affected, and the preferred vehicle may vary depending on the context in which the processes and / or systems and / or other technologies are deployed. For example, if an implementer determines that speed and accuracy are most important, the implementer may opt for a primarily hardware and / or firmware vehicle. If flexibility is most important, the implementer may opt for a primarily software implementation. Alternatively, the implementer may opt for some combination of hardware, software, and / or firmware.

[0148] The foregoing detailed description has set forth various embodiments of devices and / or processes through the use of block diagrams, flow charts, and / or examples. To the extent that such block diagrams, flow charts, and / or examples contain one or more functions and / or operations, it will be understood by those skilled in the art that each function and / or operation within such block diagrams, flow charts, or examples can be individually and / or jointly implemented by a wide range of hardware, software, firmware, or virtually any combination thereof. Suitable processors include, for example, general-purpose processors, special-purpose processors, conventional processors, digital signal processors (DSPs), multiple microprocessors, one or more microprocessors associated with a DSP core, controllers, microcontrollers, application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), field-programmable gate array (FPGA) circuits, any other type of integrated circuit (IC), and / or state machines.

[0149] While features and elements are provided above in particular combinations, those skilled in the art will recognize that each feature or element can be used alone or in any combination with the other features and elements. The present disclosure should not be limited with respect to the specific embodiments described in this application, which are intended as illustrations of various aspects. Many modifications and variations may be made without departing from its spirit and scope, as will be apparent to those skilled in the art. No element, act, or instruction used in the description of this application should be taken as critical or essential to the invention unless expressly defined as such. Functionally equivalent methods or apparatuses within the scope of the present disclosure, in addition to those enumerated herein, will be apparent to those skilled in the art from the foregoing description. Such modifications and variations are intended to fall within the scope of the appended claims. The present disclosure is to be limited only by the terms of the appended claims, along with the full range of equivalents to which such claims are entitled. It is to be understood that the present disclosure is not limited to particular methods or systems.

[0150] It should also be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, i.e., when referred to herein, the terms “station” and its abbreviation “STA,” “user equipment” and its abbreviation “UE” can mean (i) a wireless transmit and / or receive unit (WTRU), as described below; (ii) any of several embodiments of a WTRU, as described below; (iii) a wireless-capable and / or wired-capable (e.g., tetherable) device configured with, among other things, some or all of the structure and functionality of a WTRU, as described below; (iv) a wireless-capable and / or wired-capable device configured with less than all of the structure and functionality of a WTRU, as described below; or (v) others. Details of an exemplary WTRU that may represent (or be interchangeable with) any UE described herein are provided below with respect to FIGS. 1A-1D .

[0151] In certain representative embodiments, portions of the subject matter described herein may be implemented via application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), digital signal processors (DSPs), and / or other integrated forms. However, those skilled in the art will recognize that some aspects of the embodiments disclosed herein may equivalently be implemented in whole or in part in an integrated circuit as one or more computer programs running on one or more computers (e.g., as one or more programs running on one or more computer systems), as one or more programs running on one or more processors (e.g., as one or more programs running on one or more microprocessors), as firmware, or virtually any combination thereof, and that designing circuitry and / or writing code for software and / or firmware is well within the skill of those skilled in the art in light of this disclosure. Those skilled in the art will recognize that the subject matter mechanisms described herein can be delivered as program products in various forms, and that the illustrative embodiments of the subject matter described herein apply regardless of the particular type of signal-bearing medium used to actually accomplish the delivery. Examples of signal-bearing media include, but are not limited to, recordable-type media such as floppy disks, hard disk drives, CDs, DVDs, digital tape, computer memory, etc., as well as transmission-type media such as digital and / or analog communications media (e.g., fiber optic cables, wave guides, wired communications links, wireless communications links, etc.).

[0152] The subject matter described herein sometimes illustrates different components housed within or connected to different other components. It should be understood that such depicted architectures are merely examples, and that in fact many other architectures may be implemented that achieve the same functionality. In a conceptual sense, any arrangement of components to achieve the same functionality is effectively “related” such that the desired functionality may be achieved. Thus, any two components herein that combine to achieve particular functionality, regardless of the architecture or intermediate components, may be viewed as being “associated” with each other such that the desired functionality is achieved. Similarly, any two components so associated may also be considered to be “operably connected” or “operably coupled” to each other to achieve the desired functionality, and any two components capable of being so associated may also be considered to be “operably couplable” to each other to achieve the desired functionality. Specific examples of operably coupleable include, but are not limited to, physically mateable and / or physically interacting components, and / or wirelessly interactable and / or wirelessly interacting components, and / or logically interacting and / or logically interacting components.

[0153] With respect to the use of virtually any plural and / or singular term herein, those of skill in the art can substitute plural for singular and / or singular for plural as appropriate to the context and / or application. Various singular / plural permutations may be expressly specified herein for clarity.

[0154] It will be understood by those skilled in the art that the terms used herein in general, and in the appended claims in particular (e.g., the body of the appended claims), are broadly intended as “open” terms (e.g., the term “including” should be interpreted as “including, but not limited to,” the term “having” should be interpreted as “having at least,” the term “include” should be interpreted as “including, but not limited to,” etc.). Where a specific number of introduced claim recitations is intended, such intention will be expressly set forth in the claim; in the absence of such a recitation, it will be further understood by those skilled in the art that no such intention exists. For example, where only one item is intended, the term “single” or similar language may be used. As an aid to understanding, the following appended claims and / or description herein may accommodate the use of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be taken to imply that introducing a claim recitation with the indefinite article "a" or "an" limits any particular claim containing such an introduced claim recitation to embodiments containing only one such recitation, even when that same claim includes the introductory phrase "one or more" or "at least one" and an indefinite article such as "a" or "an" (e.g., "a" and / or "an" should be interpreted to mean "at least one" or "one or more"). The same applies to the use of definite articles used to introduce claim recitations. Moreover, those skilled in the art will recognize that even when a specific number of introduced claim recitations is explicitly recited, such recitation should be interpreted to mean at least the recited number (e.g., the literal recitation "two recitations" means at least two recitations, or more than two recitations, in the absence of other modifiers).

[0155] Furthermore, where traditional phraseology similar to "at least one of A, B, and C, etc." is used, such syntax is generally intended in the sense that one of ordinary skill in the art would understand the traditional phraseology (e.g., "a system having at least one of A, B, and C" would include, but is not limited to, systems having A alone, B alone, C alone, A and B together, A and C together, B and C together, and / or A, B, and C together, etc.). Where traditional phraseology similar to "at least one of A, B, or C, etc." is used, such syntax is generally intended in the sense that one of ordinary skill in the art would understand the traditional phraseology (e.g., "a system having at least one of A, B, or C" would include, but is not limited to, systems having A alone, B alone, C alone, A and B together, A and C together, B and C together, and / or A, B, and C together, etc.). It will be further understood by those skilled in the art that virtually any disjunctive word and / or phrase presenting two or more alternative terms, whether in the specification, claims, or drawings, should be understood to contemplate the possibility of including one of the terms, either of the terms, or both terms. For example, the phrase "A or B" will be understood to include the possibilities of "A" or "B" or "A and B." Furthermore, the term "any," as used herein following a list of multiple items and / or multiple categories of items, is intended to include "any," "any combination," "any more," and / or "any combination of multiple" of the items and / or categories of items, individually or in combination with other items and / or in combination with other categories of items. Moreover, as used herein, the term "set" or "group" is intended to include any number of items, including zero. Additionally, as used herein, the term "number" is intended to include any number, including zero.

[0156] In addition, when features or aspects of the present disclosure are described in terms of a Markush group, those skilled in the art will recognize that the present disclosure is also thereby described in terms of any individual member or subgroup of members of the Markush group.

[0157] As will be understood by those skilled in the art, for any and all purposes, including in terms of providing a written specification, all ranges disclosed herein also encompass any and all possible subranges and combinations of those subranges. Any listed range can be readily recognized as fully descriptive and facilitates breaking down the same range into at least equal halves, thirds, quarters, fifths, tenths, etc. As a non-limiting example, each range discussed herein may be readily broken down into a lower third, middle third, and upper third, etc. As will also be understood by those skilled in the art, all language such as "up to," "at least," "greater than," "less than," etc., refers to a range that is inclusive of the recited numbers and can be subsequently broken down into subranges as discussed above. Finally, as will be understood by those skilled in the art, a range includes each individual member. Thus, for example, a group having 1 to 3 cells refers to a group having 1, 2, or 3 cells. Similarly, a group having 1 to 5 cells refers to a group having 1, 2, 3, 4, or 5 cells, etc.

[0158] Moreover, the claims should not be read as limited to the order or elements provided unless stated to that effect. In addition, the use of the term "means for" in any claim is intended to invoke 35 U.S.C. § 112, paragraph 6, or means-plus-function claim format, and no claim would be so intended without the term "means for."

[0159] A processor in association with software may be used to implement a radio frequency transceiver for use in a wireless transmit / receive unit (WTRU), user equipment (UE), terminal, base station, mobility management entity (MME) or evolved packet core (EPC), or any host computer. The WTRU may be used in conjunction with modules implemented in hardware and / or software, including software-defined radios (SDRs) and other components such as cameras, video camera modules, videophones, speakerphones, vibration devices, speakers, microphones, television transceivers, hands-free headsets, keyboards, Bluetooth modules, frequency modulation (FM) radio units, near field communication (NFC) modules, liquid crystal display (LCD) display units, organic light-emitting diode (OLED) display units, digital music players, media players, video game player modules, internet browsers, and / or any wireless local area network (WLAN) or ultra-wideband (UWB) modules.

[0160] Although the present invention has been described in terms of a communications system, it is contemplated that the system may be implemented in software on a microprocessor / general purpose computer (not shown). In certain embodiments, one or more of the functions of the various components may be implemented in software controlling a general purpose computer.

[0161] While the invention has been illustrated and described herein with reference to specific embodiments, the invention is not intended to be limited to the details shown. Rather, various modifications may be made in the details within the realm and range of equivalents of the claims without departing from the invention.

[0162] Throughout this disclosure, those skilled in the art will understand that certain exemplary embodiments may be used in alternative embodiments or in combination with other exemplary embodiments.

[0163] Although features and elements are described above in particular combinations, those skilled in the art will recognize that each feature or element may be used alone or in any combination with the other features and elements. The methods described herein may be implemented in a computer program, software, or firmware embodied in a computer-readable medium for execution by a computer or processor. Examples of non-transitory computer-readable storage media include, but are not limited to, ROM, RAM, registers, cache memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magneto-optical media, and optical media such as CD-ROM disks and digital versatile disks (DVDs). A processor in association with software may be used to implement a radio frequency transceiver for use in a WTRU, UE, terminal, base station, RNC, or any host computer.

[0164] Moreover, in the above-described embodiments, processing platforms, computing systems, controllers, and other devices containing processors are described. These devices may contain at least one central processing unit ("CPU") and memory. In accordance with the practices of those skilled in the art of computer programming, references to acts and symbolic representations of operations or instructions may be performed by various CPUs and memories. Such acts and operations or instructions may be referred to as being "executed," "computer-executed," or "CPU-executed."

[0165] Those skilled in the art will recognize that acts and symbolically represented operations or instructions involve the manipulation of electrical signals by a CPU. The electrical system represents the data bits, resulting in the resulting transformation or reduction of the electrical signals and the maintenance of the data bits in memory locations in a memory system, thereby reconfiguring or otherwise altering the operation of the CPU and other processing of the signals. The memory locations in which the data bits are maintained are physical locations having particular electrical, magnetic, optical, or organic properties that correspond to or represent the data bits.

[0166] The data bits may also be maintained on computer-readable media, including magnetic disks, optical disks, and any other volatile (e.g., RAM) or non-volatile (e.g., ROM) mass storage systems readable by a CPU. The computer-readable media may include computer-readable media that reside exclusively on a processing system, or that are distributed among, cooperating with, or interconnected to multiple interconnected processing systems, which may be local or remote to the processing system. It will be understood that exemplary embodiments are not limited to the memories described above, and that other platforms and memories may support the described methods.

[0167] Suitable processors include, for example, a general purpose processor, a special purpose processor, a conventional processor, a digital signal processor (DSP), multiple microprocessors, one or more microprocessors in association with a DSP core, a controller, a microcontroller, an application specific integrated circuit (ASIC), an application specific standard product (ASSP), a field programmable gate array (FPGA) circuit, any other type of integrated circuit (IC), and / or a state machine.

[0168] Although the present invention has been described in terms of a communications system, it is contemplated that the system may be implemented in software on a microprocessor / general purpose computer (not shown). In certain embodiments, one or more of the functions of the various components may be implemented in software controlling a general purpose computer.

[0169] Additionally, while the invention is illustrated and described herein with reference to specific embodiments, the invention is not intended to be limited to the details shown. Rather, various modifications may be made in the details within the realm and range of equivalents of the claims without departing from the invention.

Claims

1. 1. A wireless transmit / receive unit (WTRU) comprising a processor, the processor comprising: determining, based on a field included in first downlink control information (DCI), that hybrid automatic repeat request (HARQ) feedbacks for downlink (DL) transmissions are grouped with a first set of HARQ feedbacks corresponding to a set of first DL transmissions, the field indicating via an index value that the DL transmissions are grouped with the first set of HARQ feedbacks corresponding to the set of first DL transmissions; receiving, in a second DCI, a second indication to transmit a set of HARQ feedback bits using one or more uplink (UL) control resources, the second indication including at least the index value and a HARQ retransmission indicator; transmitting the set of HARQ feedback bits using the one or more UL control resources, wherein the processor is configured to include the HARQ feedback for the DL transmission in the set of HARQ feedback bits based on the HARQ feedback for the DL transmission being grouped with a first set of HARQ feedback, an index value included in the second DCI, and the HARQ retransmission indicator included in the second DCI; A WTRU configured to perform

2. The WTRU of claim 1 , wherein the first DCI and the second DCI are the same DCI.

3. 2. The WTRU of claim 1, wherein the processor is further configured to exclude HARQ feedback for a second DL transmission from the set of HARQ feedback bits based on the HARQ feedback for the second DL transmission being grouped with a second set of HARQ feedback corresponding to the set of second DL transmissions, the second set of HARQ feedback being associated with a second index value that is different from the index value associated with the first set of HARQ feedback.

4. The processor: receiving, via higher layer signaling, a configuration for grouping HARQ feedback; determining, based on the configuration for grouping HARQ feedbacks and the field included in the first DCI, that HARQ feedbacks for the DL transmissions are grouped with the first set of HARQ feedbacks corresponding to the first set of DL transmissions; The WTRU of claim 1 further configured to perform:

5. The processor:

2. The WTRU of claim 1, further configured to include HARQ feedback for a second DL transmission in a set of HARQ feedback bits based on the HARQ feedback for the second DL transmission being grouped with a second set of HARQ feedback corresponding to the set of second DL transmissions, the second set of HARQ feedback being associated with a second index value that is different from the index value associated with the first set of HARQ feedback.

6. 10. The WTRU of claim 1, wherein the one or more UL control resources are included in a physical uplink control channel (PUCCH).

7. 1. A method for a wireless transmit / receive unit (WTRU), comprising: determining, based on a field included in first downlink control information (DCI), that hybrid automatic repeat request (HARQ) feedbacks for downlink (DL) transmissions are grouped with a first set of HARQ feedbacks corresponding to a set of first DL transmissions, the field indicating via an index value that the DL transmissions are grouped with the first set of HARQ feedbacks corresponding to the set of first DL transmissions; receiving, in a second DCI, a second indication to transmit a set of HARQ feedback bits using one or more uplink (UL) control resources, the second indication including at least the index value and a HARQ retransmission indicator; transmitting the set of HARQ feedback bits using the one or more UL control resources, wherein the HARQ feedback for the DL transmission is included in the set of HARQ feedback bits based on the HARQ feedback for the DL transmission being grouped with a first set of HARQ feedback, an index value included in the second DCI, and the HARQ retransmission indicator included in the second DCI; A method comprising:

8. The method of claim 7 , wherein the first DCI and the second DCI are the same DCI.

9. 8. The method of claim 7, further comprising: excluding HARQ feedback for a second DL transmission from the set of HARQ feedback bits based on the HARQ feedback for the second DL transmission being grouped with a second set of HARQ feedback corresponding to the set of second DL transmissions, the second set of HARQ feedback being associated with a second index value that is different from the index value associated with the first set of HARQ feedback.

10. receiving, via higher layer signaling, a configuration for grouping HARQ feedback; determining, based on the configuration for grouping HARQ feedbacks and the field included in the first DCI, that HARQ feedbacks for the DL transmissions are grouped with the first set of HARQ feedbacks corresponding to the first set of DL transmissions; 8. The method of claim 7, further comprising:

11. 8. The method of claim 7, further comprising: including HARQ feedback for a second DL transmission in a set of HARQ feedback bits based on the HARQ feedback for the second DL transmission being grouped with a second set of HARQ feedback corresponding to the set of second DL transmissions, the second set of HARQ feedback being associated with a second index value, the second index value being different from the index value associated with the first set of HARQ feedback.

12. 8. The method of claim 7, wherein the one or more UL control resources are included in a Physical Uplink Control Channel (PUCCH).

13. 1. A network node comprising a processor, the processor comprising: transmitting, to a wireless transmit / receive unit (WTRU), first downlink control information (DCI), the first DCI including a field indicating via an index value that hybrid automatic repeat request (HARQ) feedback for a downlink (DL) transmission is grouped with a first set of HARQ feedback corresponding to the first set of DL transmissions; transmitting a second DCI to the WTRU, the second DCI including a second indication that the WTRU will transmit a set of HARQ feedback bits using one or more uplink (UL) control resources, the second indication including at least the index value and a HARQ retransmission indicator; receiving the set of HARQ feedback bits using the one or more UL control resources, the set of HARQ feedback bits including HARQ feedback for the DL transmission; and 2. A network node configured to run:

14. The network node of claim 13 , wherein the first DCI and the second DCI are the same DCI.

15. The network node of claim 13 , wherein the set of HARQ feedbacks includes only HARQ feedbacks for a first set of HARQ feedbacks corresponding to a first set of DL transmissions.

16. The processor:

14. The network node of claim 13, further configured to: transmit via higher layer signaling a configuration for grouping HARQ feedback, wherein the configuration for grouping HARQ feedback and the field included in the first DCI indicate that HARQ feedback for the DL transmissions is to be grouped with the first set of HARQ feedback corresponding to the first set of DL transmissions.

17. 14. The network node of claim 13, wherein the set of HARQ feedback bits includes HARQ feedback for a second DL transmission, the HARQ feedback for the second DL transmission being grouped with a second set of HARQ feedback corresponding to the second set of DL transmissions, the second set of HARQ feedback being associated with a second index value, the second index value being different from the index value associated with the first set of HARQ feedback.

18. The network node of claim 13 , wherein the one or more UL control resources are included in a Physical Uplink Control Channel (PUCCH).

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