Opportunistic acknowledgement transmission

Abstract

A wireless transmit / receive unit (WTRU) may receive a plurality of downlink signals. The WTRU may receive first configuration information indicating a first time and frequency resource for transmitting a hybrid automatic repeat request (HARQ) acknowledgement (ACK). The WTRU may receive second configuration information indicating a second time and frequency resource for transmitting the HARQ-ACK. The second configuration information may indicate one or more sequences to be transmitted using the second time and frequency resources. The WTRU may transmit at least one sequence of the one or more sequences using the second time and frequency resource. The at least one sequence of the one or more sequences may be transmitted using the second time and frequency resource to indicate an ACK associated with the plurality of downlink signals.

Description

[0001] Cross - reference to related applications

[0002] This application claims priority to U.S. Provisional Application No. 63 / 421,698, filed on Nov. 2, 2022, the entire text of which is incorporated herein by reference. Background of the Invention

[0003] The transmission timing of hybrid automatic repeat request (HARQ) acknowledgments (ACKs) / negative ACKs (NACKs) is configurable (e.g., in New Radio Time Division Duplex (NR - TDD)). The HARQ ACK / NACK timing for receiving downlink signals and / or channels can be configured by one or more higher - layer parameters indicating one or more parameters. The one or more parameters indicate indices and can be included in the Physical Uplink Control Channel (PUCCH) configuration. One or more of these parameters can be included. The number of bits and the selection for each parameter are examples. Other numbers of bits or selections can be included.

[0004] The timing indication for transmitting feedback and / or acknowledgments in NR - TDD can result in latency, e.g., because the timing is based on a semi - static configuration of uplink time slots. However, considering dynamic TDD, multiple time units can be dynamically configured as uplinks. In addition, a sub - band non - overlapping full - duplex (SBFD) scheme has been proposed to include uplink sub - bands within downlink time units, thereby increasing uplink transmission opportunities. Summary of the Invention

[0005] A wireless transmit / receive unit (WTRU) can include a transceiver and a processor. The processor can be configured to receive a plurality of downlink signals via the transceiver. The processor can also be configured to receive first configuration information via the transceiver, the first configuration information indicating a first time and frequency resource for transmitting a hybrid automatic repeat request (HARQ) acknowledgment (ACK). The processor can also be configured to receive second configuration information via the transceiver, the second configuration information indicating a second time and frequency resource for transmitting HARQ - ACK. The second configuration information can indicate one or more sequences to be transmitted using the second time and frequency resource. The processor can also be configured to transmit at least one of the one or more sequences via the transceiver using the second time and frequency resource. The at least one of the one or more sequences can be transmitted using the second time and frequency resource to indicate an ACK associated with the plurality of downlink signals.

[0006] The transceiver may be configured to transmit a negative acknowledgment (NACK) associated with the plurality of downlink signals using the first time and frequency resources. The second time and frequency resources may include one or more uplink subbands within a subband non-overlapping full-duplex (SBFD) download time unit. The second time and frequency resources may be indicated via one or more of implicit indication, explicit indication, semi-static indication, and dynamic indication. The second time and frequency resources may be cell-specific. The second time and frequency resources may indicate an earlier time instance compared to the first time and frequency resources. The plurality of downlink signals may be received based on a higher layer configuration that may be associated with the first time and frequency resources or the second time and frequency resources. The at least one sequence among the one or more sequences may be transmitted at a time instance determined based on the second time and frequency resources and each of the plurality of downlink signals. The NACK for one or more of the plurality of downlink signals using the first time and frequency resources may be transmitted at a time instance determined based on the first time and frequency resources and each of the plurality of downlink signals. The second time and frequency resources may be associated with time slots within a subband non-overlapping full-duplex (SBFD) resource block. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1A is a system diagram illustrating an example communication system in which one or more disclosed embodiments may be implemented.

[0008] Figure 1B is a system diagram illustrating an example wireless transmit / receive unit (WTRU) that may be used within the Figure 1A illustrated communication system, according to an embodiment.

[0009] Figure 1C is a system diagram illustrating an example radio access network (RAN) and an example core network (CN) that may be used within the Figure 1A illustrated communication system, according to an embodiment.

[0010] Figure 1D is a system diagram illustrating yet another example RAN and yet another example CN that may be used within the Figure 1A illustrated communication system, according to an embodiment.

[0011] Figure 2 depicts an example hybrid automatic repeat request (HARQ) acknowledgment (ACK) (HARQ-ACK) timing indication.

[0012] Figure 3 is a flow diagram illustrating an example opportunistic transmission of an ACK for one or more downlink receptions.

[0013] Figure 4 depicts an example subband full-duplex (SBFD) configuration without overlap.

[0014] Figure 5 depicts an example opportunistic HARQ-ACK transmission.

[0015] Figure 6 depicts an example opportunistic acknowledgment transmission for high-priority downlink control information (DCI). Detailed Description

[0016] Figure 1A is a diagram showing an example communication system 100 in which one or more of the disclosed embodiments may be implemented. The communication system 100 may be a multi-access system that provides content such as voice, data, video, messaging, broadcasting, etc. to a plurality of wireless users. The communication system 100 may enable a plurality of wireless users to access such content through shared system resources including wireless broadband. 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-tail unique word DFT-spread OFDM (ZT UW DTS-s OFDM), unique word OFDM (UW-OFDM), resource block filtered OFDM, filter bank multicarrier (FBMC), etc.

[0017] As Figure 1AAs shown, the communication system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, a radio access network (RAN) 104 / 113, a core network (CN) 106 / 115, a public switched telephone network (PSTN) 108, the Internet 110, and other networks 112, but it will be appreciated that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network elements. Each of the WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and / or communicate in a wireless environment. By way of example, the WTRUs 102a, 102b, 102c, 102d (any one 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 a user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a subscription-based unit, a pager, a cellular phone, a personal digital assistant (PDA), a smartphone, a laptop computer, a netbook, a personal computer, a wireless sensor, a hotspot or Mi-Fi device, an Internet of Things (IoT) device, a watch or other wearable device, 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., a robot and / or other wireless devices operating in the context of an industrial and / or automation processing chain), a consumer electronic device, a device operating on a commercial and / or industrial wireless network, etc. Any one of the WTRUs 102a, 102b, 102c, 102d may be interchangeably referred to as a WTRU.

[0018] The communication system 100 may also include base stations 114a and / or base stations 114b. Each of the base stations 114a, 114b may be any type of device configured to wirelessly interface with at least one of the WTRUs 102a, 102b, 102c, 102d to facilitate access to one or more communication networks such as the CN 106 / 115, the Internet 110, and / or other networks 112. By way of example, the base stations 114a, 114b may be a base transceiver station (BTS), a NodeB, an eNode B, a home NodeB, a home eNode B, a gNB, an 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.

[0019] Base station 114a may be part of RAN 104 / 113, which may also include other base stations and / or network elements (not shown), such as base station controllers (BSCs), radio network controllers (RNCs), relay nodes, etc. 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 cells (not shown). These frequencies may be in licensed spectrum, unlicensed spectrum, or a combination of licensed and unlicensed spectrum. A cell may provide wireless service coverage to a specific geographical area that may be relatively fixed or may change over time. A cell may also be divided into cell sectors. For example, the cell associated with base station 114a may be divided into three sectors. Thus, in one embodiment, base station 114a may include three transceivers, i.e., one transceiver for each sector of the cell. In an embodiment, base station 114a may employ multiple-input multiple-output (MIMO) technology and may utilize multiple transceivers for each sector of the cell. For example, beamforming may be used to transmit and / or receive signals in a desired spatial direction.

[0020] Base stations 114a, 114b may communicate with one or more of WTRUs 102a, 102b, 102c, 102d via air interface 116, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, centimeter wave, millimeter wave, infrared (IR), ultraviolet (UV), visible light, etc.). Any suitable radio access technology (RAT) may be used to establish air interface 116.

[0021] More specifically, as described above, communication system 100 may be a multiple access system and may employ one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, etc. For example, base station 114a in RAN 104 / 113, as well as WTRUs 102a, 102b, 102c, may implement radio technologies, such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA) that may use Wideband CDMA (WCDMA) to establish air interfaces 115 / 116 / 117. 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).

[0022] In an embodiment, base station 114a and WTRUs 102a, 102b, 102c may implement radio technologies, such as evolved UMTS terrestrial radio access (E-UTRA) that may use Long Term Evolution (LTE) and / or LTE-Advanced (LTE-A) and / or LTE-A Pro (LTE-A Pro) to establish an air interface 116.

[0023] In an embodiment, base station 114a and WTRUs 102a, 102b, 102c may implement radio technologies, such as New Radio (NR) radio access that may use NR to establish an air interface 116.

[0024] In an embodiment, base station 114a and WTRUs 102a, 102b, 102c may implement multiple radio access technologies. For example, base station 114a and WTRUs 102a, 102b, 102c may jointly implement LTE radio access and NR radio access using, for example, the dual connectivity (DC) principle. Thus, the air interfaces used by WTRUs 102a, 102b, 102c may be characterized by multiple types of radio access technologies and / or transmissions to / from multiple types of base stations (e.g., eNBs and gNBs).

[0025] In other embodiments, base station 114a and WTRUs 102a, 102b, 102c may implement radio technologies such as IEEE 802.11 (i.e., Wi-Fi), IEEE 802.16 (i.e., 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 Rate for GSM Evolution (EDGE), GSM EDGE (GERAN), etc.

[0026] Figure 1AThe base station 114b therein may be, for example, a wireless router, a home NodeB, a home eNode-B, or an access point, and may utilize any suitable RAT to facilitate wireless connectivity in a local area such as a commercial premise, a home, a vehicle, a campus, an industrial facility, an aviation corridor (e.g., for drones), a road, etc. 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 pico cell or a femto cell. As Figure 1A shown, the base station 114b may be directly connected to the Internet 110. Thus, the base station 114b may not need to access the Internet 110 via the CN 106 / 115.

[0027] The RAN 104 / 113 may communicate with the CN 106 / 115, which may be any type of network configured to provide voice, data, applications, and / or voice over Internet Protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. The data may have different quality of service (QoS) requirements such as different throughput requirements, latency requirements, fault tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, etc. The CN 106 / 115 may provide call control, billing services, location-based services, prepaid calling, Internet connectivity, video distribution, etc., and / or perform advanced security functions such as user authentication. Although Figure 1A not shown, it will be appreciated that the RAN 104 / 113 and / or the CN 106 / 115 may communicate directly or indirectly with other RANs employing the same RAT or a different RAT as the RAN 104 / 113. For example, in addition to being connected to the RAN 104 / 113 that may be utilizing NR radio technology, the CN 106 / 115 may also communicate with another RAN (not shown) employing GSM, UMTS, CDMA 2000, WiMAX, E-UTRA, or WiFi radio technology.

[0028] CN 106 / 115 can also serve as a gateway for WTRU 102a, 102b, 102c, 102d to access the PSTN 108, the Internet 110, and / or other networks 112. The PSTN 108 can include a circuit-switched telephone network that provides Plain Old Telephone Service (POTS). The Internet 110 can include a global system of interconnected computer networks and devices that use common communication protocols such as Transmission Control Protocol (TCP), User Datagram Protocol (UDP), and / or Internet Protocol (IP) in the TCP / IP Internet protocol suite. The network 112 can include wired and / or wireless communication networks owned and / or operated by other service providers. For example, the network 112 can include another CN connected to one or more RANs, and the other CN can employ the same RAT or a different RAT as the RAN 104 / 113.

[0029] Some or all of the WTRU 102a, 102b, 102c, 102d in the communication system 100 can include multi-mode capabilities (e.g., the WTRU 102a, 102b, 102c, 102d can include multiple transceivers for communicating with different wireless networks over different wireless links). For example, Figure 1A the illustrated WTRU 102c can be configured to communicate with a base station 114a that can employ a cellular-based radio technology and with a base station 114b that can employ IEEE 802 radio technology.

[0030] Figure 1B is a system diagram showing an exemplary WTRU 102. As Figure 1B shown, the WTRU 102 can include a processor 118, a transceiver 120, transmit / receive elements 122, a speaker / microphone 124, a keypad 126, a display / touchpad 128, a non-removable memory 130, a removable memory 132, a power supply 134, a Global Positioning System (GPS) chipset 136, and / or other peripheral devices 138, etc. It will be appreciated that the WTRU 102 can include any sub-combination of the foregoing elements while remaining consistent with the embodiments.

[0031] The processor 118 can be a general-purpose processor, a dedicated processor, a conventional processor, a digital signal processor (DSP), multiple microprocessors, one or more microprocessors associated with a DSP core, a controller, a microcontroller, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) circuit, any other type of integrated circuit (IC), a state machine, etc. The processor 118 can perform signal encoding, data processing, power control, input / output processing, and / or any other functions that enable the WTRU 102 to operate in a wireless environment. The processor 118 can be coupled to a transceiver 120, which can be coupled to a transmit / receive element 122. Although Figure 1B the processor 118 and the transceiver 120 are depicted as separate components, it will be appreciated that the processor 118 and the transceiver 120 can be integrated together in an electronic package or chip.

[0032] The transmit / receive element 122 can be configured to transmit signals to or receive signals from a base station (e.g., base station 114a) via an air interface 116. For example, in one embodiment, the transmit / receive element 122 can be an antenna configured to transmit and / or receive RF signals. In an embodiment, for example, the transmit / receive element 122 can be a transmitter / detector configured to transmit and / or receive, for example, IR, UV, or visible light signals. In another embodiment, the transmit / receive element 122 can be configured to transmit and / or receive both RF signals and optical signals. It will be appreciated that the transmit / receive element 122 can be configured to transmit and / or receive any combination of wireless signals.

[0033] Although the transmit / receive element 122 is depicted as a single element in Figure 1B the WTRU 102 can include any number of transmit / receive elements 122. More specifically, the WTRU 102 can employ MIMO technology. Thus, in one embodiment, the WTRU 102 can include two or more transmit / receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals via the air interface 116.

[0034] The transceiver 120 can be configured to modulate the signals to be transmitted by the transmit / receive element 122 and demodulate the signals received by the transmit / receive element 122. As described above, the WTRU 102 can have multi-mode capabilities. Thus, the transceiver 120 can include multiple transceivers for enabling the WTRU 102 to communicate via multiple RATs (e.g., such as NR and IEEE 802.11).

[0035] The processor 118 of the WTRU 102 can be coupled to and 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 can also output user data to the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128. Additionally, the processor 118 can access information from and store data in any type of suitable memory such as a non-removable memory 130 and / or a removable memory 132. The non-removable memory 130 can include random access memory (RAM), read only memory (ROM), a hard disk, or any other type of memory storage device. The removable memory 132 can include a subscriber identity module (SIM) card, a memory stick, a secure digital (SD) memory card, etc. In other embodiments, the processor 118 can access information from and store data in a memory that is not actually located on the WTRU 102, such as on a server or a home computer (not shown).

[0036] The processor 118 can receive power from a power source 134 and can be configured to distribute power to and / or control the power to other components in the WTRU 102. The power source 134 can be any suitable device for powering the WTRU 102. For example, the power source 134 can include one or more dry cell batteries (e.g., nickel cadmium (NiCd), nickel zinc (NiZn), nickel metal hydride (NiMH), lithium ion (Li-ion), etc.), a solar cell, a fuel cell, etc.

[0037] The processor 118 can also be coupled to a GPS chipset 136, which can be configured to provide location information (e.g., longitude and latitude) about the current location of the WTRU 102. In addition to or instead of information from the GPS chipset 136, the WTRU 102 can receive location information from a base station (e.g., base stations 114a, 114b) via an air interface 116 and / or determine its location based on the timing of signals received from two or more nearby base stations. It will be appreciated that the WTRU 102 can obtain location information by any suitable location determination method while remaining consistent with the embodiments.

[0038] The processor 118 can also be coupled to other peripheral devices 138, which can include one or more software and / or hardware modules that provide additional features, functions, and / or wired or wireless connections. For example, the peripheral devices 138 can include an accelerometer, an electronic compass, a satellite transceiver, a digital camera (for photos and / or videos), a universal serial bus (USB) port, a vibration device, a television transceiver, a hands-free headset, Modules, FM radio units, digital music players, media players, video game player modules, Internet browsers, virtual reality and / or augmented reality (VR / AR) devices, activity trackers, etc. Peripheral device 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 geographical location sensor, an altimeter, a light sensor, a touch sensor, a magnetometer, a barometer, a gesture sensor, a biometric sensor, and / or a humidity sensor.

[0039] The WTRU 102 may include a full-duplex radio, where some or all of the transmission and reception of signals (e.g., associated with a particular subframe for both UL (e.g., for transmission) and downlink (e.g., for reception)) may be concurrent and / or simultaneous. The full-duplex radio may include an interference management unit 139 to reduce and / or substantially eliminate self-interference via hardware (e.g., chokes) or signal processing via a processor (e.g., a separate processor (not shown) or via processor 118). In an embodiment, the WRTU 102 may include a half-duplex radio, where some or all of the transmission and reception of signals (e.g., associated with a particular subframe for either UL (e.g., for transmission) or downlink (e.g., for reception)).

[0040] Figure 1C is a system diagram showing the RAN 104 and CN 106 according to an embodiment. As described above, the RAN 104 may employ E-UTRA radio technology to communicate with the WTRUs 102a, 102b, 102c via the air interface 116. The RAN 104 may also communicate with the CN 106.

[0041] The RAN 104 may include eNode-Bs 160a, 160b, 160c, but it will be understood that the RAN 104 may include any number of eNode-Bs while remaining consistent with the embodiment. The eNode-Bs 160a, 160b, 160c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c via the air interface 116. In one embodiment, the eNode-Bs 160a, 160b, 160c may implement MIMO technology. Thus, for example, the eNode-B 160a may use multiple antennas to transmit wireless signals to and / or receive wireless signals from the WTRU 102a.

[0042] Each of eNode-Bs 160a, 160b, and 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, user scheduling in UL and / or DL, etc. As Figure 1C shown, eNode-Bs 160a, 160b, and 160c may communicate with each other via the X2 interface.

[0043] Figure 1C The illustrated CN 106 may include a Mobility Management Entity (MME) 162, a Serving Gateway (SGW) 164, and a Packet Data Network (PDN) Gateway (PGW) 166. Although each of the foregoing elements is described as part of 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.

[0044] The MME 162 may be connected to each of eNode-Bs 162a, 162b, and 162c in the RAN 104 via the S1 interface and may act as a control node. For example, the MME 162 may be responsible for authenticating users of WTRUs 102a, 102b, and 102c, bearer activation / deactivation, selecting a particular serving gateway during the initial contact of WTRUs 102a, 102b, and 102c, etc. The MME 162 may provide control plane functions for handover between the RAN 104 and other RANs (not shown) employing other radio technologies such as GSM and / or WCDMA.

[0045] The SGW 164 may be connected to each of eNode Bs 160a, 160b, and 160c in the RAN 104 via the S1 interface. The SGW 164 may generally route and forward user data packets to and from the WTRUs 102a, 102b, and 102c. The SGW 164 may perform other functions such as anchoring the user plane during handover between eNode-Bs, triggering paging when DL data is available for the WTRUs 102a, 102b, and 102c, managing and storing the context of the WTRUs 102a, 102b, and 102c, etc.

[0046] The SGW 164 may be connected to the PGW 166, which may provide the WTRUs 102a, 102b, and 102c with access to a packet switched network such as the Internet 110 to facilitate communication between the WTRUs 102a, 102b, and 102c and IP-enabled devices.

[0047] CN 106 can facilitate communication with other networks. For example, CN 106 can provide the WTRUs 102a, 102b, 102c with access to a circuit-switched network (such as the PSTN 108) to facilitate communication between the WTRUs 102a, 102b, 102c and traditional landline communication devices. For example, CN 106 can include an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that serves as an interface between CN 106 and the PSTN 108 or can communicate therewith. Additionally, CN 106 can provide the WTRUs 102a, 102b, 102c with access to other networks 112, which can include other wired and / or wireless networks owned and / or operated by other service providers.

[0048] Although the WTRU is depicted as a wireless terminal in Figures 1A to 1D it is envisioned that in some representative embodiments, such a terminal can (e.g., temporarily or permanently) use a wired communication interface with the communication network.

[0049] In a representative embodiment, the other network 112 can be a WLAN.

[0050] A WLAN in infrastructure basic service set (BSS) mode can have an access point (AP) for the BSS and one or more stations (STAs) associated with the AP. The AP can have access to or an interface with a distribution system (DS) or another type of wired / wireless network that loads and / or unloads traffic to / from the BSS. Traffic destined for an STA from outside the BSS can reach the STA through the AP and can be delivered to the STA. Traffic originating from an STA destined for a destination outside the BSS can be sent to the AP for delivery to the corresponding destination. Traffic between STAs within the BSS can be sent through the AP, e.g., where the source STA can send traffic to the AP and the AP can deliver the traffic to the destination STA. Traffic between STAs within the BSS can be considered and / or referred to as peer-to-peer traffic. Peer-to-peer traffic can be sent between the source STA and the destination STA using direct link setup (DLS) (e.g., sent directly between them). In some representative embodiments, the DLS can use 802.11e DLS or 802.11z tunnel DLS (TDLS). A WLAN using independent BSS (IBSS) mode may not have an AP, and STAs within the IBSS or using the IBSS (e.g., all STAs) can communicate directly with each other. The IBSS communication mode can sometimes be referred to in this document as an "ad hoc" communication mode.

[0051] When operating in the 802.11ac infrastructure mode or a similar operating mode, the AP can transmit beacons on a fixed channel, such as the primary channel. The primary channel can be of a fixed width (e.g., a bandwidth of 20 MHz wide) or a width dynamically set via signaling. The primary channel can be the operating channel of the BSS and can be used by the STA to establish a connection with the AP. In some representative embodiments, Carrier Sense Multiple Access with Collision Avoidance (CSMA / CA) can be implemented, for example, in an 802.11 system. For CSMA / CA, STAs including the AP (e.g., each STA) can sense the primary channel. If a particular STA senses / detects the primary signal and / or determines the primary signal to be busy, the particular STA can back off. One STA (e.g., only one station) can transmit in a given BSS at any given time.

[0052] High Throughput (HT) STAs can communicate using a 40 MHz wide channel, for example, formed by combining the primary 20 MHz channel with an adjacent or non - adjacent 20 MHz channel.

[0053] Very High Throughput (VHT) STAs can support channels that are 20 MHz, 40 MHz, 80 MHz, and / or 160 MHz wide. 40 MHz and / or 80 MHz channels can be formed by combining consecutive 20 MHz channels. A 160 MHz channel can be formed by combining eight consecutive 20 MHz channels or by combining two non - consecutive 80 MHz channels, which can be referred to as an 80 + 80 configuration. For the 80 + 80 configuration, after channel coding, the data can be passed through a fragment parser, which can divide the data into two streams. Inverse Fast Fourier Transform (IFFT) processing and time - domain processing can be performed on each stream separately. The streams can be mapped to two 80 MHz channels, and the data can be transmitted by the transmitting STA. At the receiver of the receiving STA, the above operations for the 80 + 80 configuration can be reversed, and the combined data can be sent to the Media Access Control (MAC).

[0054] 802.11af and 802.11ah support operation modes below 1 GHz. The channel operation bandwidth and carriers are reduced in 802.11af and 802.11ah as 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, and 802.11ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths using the non-TVWS spectrum. According to a representative embodiment, 802.11ah can support meter type control / machine type communication, such as MTC devices in a macro coverage area. The MTC devices can have certain capabilities, e.g., limited capabilities, including supporting (e.g., only supporting) certain and / or limited bandwidths. The MTC devices can include a battery with a battery life higher than a threshold (e.g., to maintain a very long battery life).

[0055] A WLAN system that can support multiple channels and channel bandwidths (such as 802.11n, 802.11ac, 802.11af, and 802.11ah) includes a channel that can be designated as a primary channel. The primary channel can have a bandwidth equal to the maximum common operation bandwidth supported by all STAs in a BSS. The bandwidth of the primary channel can be set and / or restricted by the STA that supports the minimum bandwidth operation mode among all STAs operating in the BSS. In an example of 802.11ah, for an STA that supports (e.g., only supports) the 1 MHz mode (e.g., an MTC type device), the primary channel can be 1 MHz wide, even if the AP and other STAs in the BSS support 2 MHz, 4 MHz, 8 MHz, 16 MHz, and / or other channel bandwidth operation modes. Carrier sensing and / or network allocation vector (NAV) setting can depend on the state of the primary channel. If the primary channel is busy, for example, due to an STA (which only supports the 1 MHz operation mode) transmitting to the AP, the entire available frequency band can be considered busy even if most of the band remains idle and may be available.

[0056] In the United States, the available frequency band that can be used by 802.11ah is 902 MHz to 928 MHz. In Korea, the available frequency band is 917.5 MHz to 923.5 MHz. In Japan, the available frequency band is 916.5 MHz to 927.5 MHz. The total bandwidth available for 802.11ah is 6 MHz to 26 MHz, depending on the country code.

[0057] Figure 1DFIG. 0 is a system diagram showing RAN 113 and CN 115 according to an embodiment. As described above, RAN 113 may employ NR radio technology to communicate with WTRUs 102a, 102b, 102c via air interface 116. RAN 113 may also communicate with CN 115.

[0058] RAN 113 may include gNBs 180a, 180b, 180c, but it will be understood that RAN 113 may include any number of gNBs while remaining consistent with the embodiment. gNBs 180a, 180b, 180c may each include one or more transceivers for communicating with WTRUs 102a, 102b, 102c via air interface 116. In one embodiment, gNBs 180a, 180b, 180c may implement MIMO technology. For example, gNBs 180a, 108b may utilize beamforming to transmit signals to and / or receive signals from gNBs 180a, 180b, 180c. Thus, for example, gNB 180a may use multiple antennas to transmit wireless signals to WTRU102a and / or receive wireless signals from that WTRU. In an embodiment, gNBs 180a, 180b, 180c may implement carrier aggregation technology. For example, gNB 180a may transmit multiple component carriers to WTRU 102a (not shown). A subset of these component carriers may be located on unlicensed spectrum while the remaining component carriers may be located on licensed spectrum. In an embodiment, gNBs 180a, 180b, 180c may implement coordinated multi-point (CoMP) technology. For example, WTRU 102a may receive coordinated transmissions from gNB 180a and gNB 180b (and / or gNB 180c).

[0059] WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using transmissions associated with a scalable digital architecture. For example, the OFDM symbol interval and / or the OFDM subcarrier interval may vary for different transmissions, different cells, and / or different portions of the radio transmission spectrum. WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using subframes or transmission time intervals (TTIs) of various lengths or scalable lengths (e.g., containing different numbers of OFDM symbols and / or lasting for different lengths of absolute time).

[0060] gNBs 180a, 180b, 180c can be configured to communicate with WTRUs 102a, 102b, 102c in stand-alone configuration and / or non-stand-alone configuration. In stand-alone configuration, WTRUs 102a, 102b, 102c can communicate with gNBs 180a, 180b, 180c without also accessing another RAN (e.g., such as eNode Bs 160a, 160b, 160c). In stand-alone configuration, WTRUs 102a, 102b, 102c can use one or more of gNBs 180a, 180b, 180c as a mobility anchor. In stand-alone configuration, WTRUs 102a, 102b, 102c can communicate with gNBs 180a, 180b, 180c using signals in an unlicensed band. In non-stand-alone configuration, WTRUs 102a, 102b, 102c can communicate / connect with gNBs 180a, 180b, 180c while also communicating / connecting with another RAN (such as eNode-Bs 160a, 160b, 160c). For example, WTRUs 102a, 102b, 102c can implement the DC principle to communicate with one or more gNBs 180a, 180b, 180c and one or more eNode-Bs 160a, 160b, 160c substantially simultaneously. In non-stand-alone configuration, eNode-Bs 160a, 160b, 160c can act as a mobility anchor for WTRUs 102a, 102b, 102c, and gNBs 180a, 180b, 180c can provide additional coverage and / or throughput to serve WTRUs 102a, 102b, 102c.

[0061] Each of gNBs 180a, 180b, 180c can be associated with a specific cell (not shown) and can be configured to handle radio resource management decisions, handover decisions, user scheduling in UL and / or DL, support for network 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 Figure 1D shown, gNBs 180a, 180b, 180c can communicate with each other via the Xn interface.

[0062] Figure 1DThe illustrated CN 115 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 data networks (DN) 185a, 185b. Although each of the foregoing elements is described as part of 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.

[0063] AMF 182a, 182b may be connected to one or more of gNBs 180a, 180b, 180c in RAN 113 via the N2 interface and may act as a control node. For example, AMF 182a, 182b may be responsible for authenticating users of WTRUs 102a, 102b, 102c, supporting network slicing (e.g., handling different PDU sessions with different requirements), selecting a particular SMF 183a, 183b, managing the registration area, terminating NAS signaling, mobility management, etc. AMF 182a, 182b may use network slicing in order to customize the CN support for WTRUs 102a, 102b, 102c based on the type of service that the WTRUs 102a, 102b, 102c are utilizing. For example, different network slices may be established for different use cases, such as services that rely on ultra-reliable low-latency (URLLC) access, services that rely on enhanced massive mobile broadband (eMBB) access, services for machine type communication (MTC) access, etc. AMF 162 may provide control plane functions for handovers between 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).

[0064] SMF 183a, 183b may be connected to AMF 182a, 182b in CN 115 via the N11 interface. SMF 183a, 183b may also be connected to UPF 184a, 184b in CN 115 via the N4 interface. SMF 183a, 183b may select and control UPF 184a, 184b and configure the routing of traffic through UPF 184a, 184b. SMF 183a, 183b may perform other functions, such as managing and allocating WTRU IP addresses, managing PDU sessions, controlling policy enforcement and QoS, providing downlink data notifications, etc. The PDU session type may be IP-based, non-IP-based, Ethernet-based, etc.

[0065] UPF 184a and 184b can be connected to one or more of gNBs 180a, 180b, and 180c in the RAN 113 via the N3 interface. The gNB can provide access to a packet-switched network (such as the Internet 110) to the WTRUs 102a, 102b, and 102c to facilitate communication between the WTRUs 102a, 102b, and 102c and IP-enabled devices. UPF 184a and 184b can perform other functions, such as routing and forwarding packets, implementing user plane policies, supporting multi-homed PDU sessions, handling user plane QoS, buffering downlink packets, providing mobile anchoring, etc.

[0066] The CN 115 can facilitate communication with other networks. For example, the CN 115 can include an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) as an interface between the CN 115 and the PSTN 108 or can communicate with the IP gateway. Additionally, the CN 115 can provide access to other networks 112 to the WTRUs 102a, 102b, and 102c. The other networks can include other wired and / or wireless networks owned and / or operated by other service providers. In one embodiment, the WTRUs 102a, 102b, and 102c can be connected to the DNs 185a and 185b via the UPFs 184a and 184b through the N3 interface to the UPFs 184a and 184b and the N6 interface between the UPFs 184a and 184b and the local data networks (DNs) 185a and 185b.

[0067] In view of Figures 1A to 1D and Figures 1A to 1D the corresponding descriptions, one or more of the functions described herein with respect to one or more or all of the following can be performed by one or more emulation devices (not shown): WTRUs 102a to 102d, base stations 114a to 114b, eNode-Bs 160a to 160c, MME 162, SGW 164, PGW 166, gNBs 180a to 180c, AMFs 182a to 182ab, UPFs 184a to 184b, SMFs 183a to 183b, DNs 185a to 185b, and / or any other device described herein. The emulation device(s) can be one or more devices configured to emulate one or more or all of the functions described herein. For example, the emulation device(s) can be used to test other devices and / or simulate network and / or WTRU functions.

[0068] The simulation device can be designed to implement one or more tests on other devices in a laboratory environment and / or an operator network environment. For example, one or more simulation devices can perform one or more or all functions when implemented and / or deployed, either fully or partially, as part of a wired and / or wireless communication network, in order to test other devices within the communication network. One or more simulation devices can perform one or more or all functions when temporarily implemented / deployed as part of a wired and / or wireless communication network. The simulation device can be directly connected to another device for testing purposes and / or can use over-the-air wireless communication to perform tests.

[0069] One or more simulation devices can perform one or more (including all) functions when not implemented / deployed as part of a wired and / or wireless communication network. For example, the simulation device can be used in a test laboratory and / or in a test scenario in a non-deployed (e.g., test) wired and / or wireless communication network in order to implement tests on one or more components. One or more simulation devices can be test equipment. The simulation device can transmit and / or receive data using a direct RF connection and / or wireless communication via an RF circuit (e.g., which can include one or more antennas).

[0070] In NR-TDD, the transmission timing of HARQ ACK / NACK is configurable. The HARQ ACK / NACK timing for receiving downlink signals and / or channels can be configured by one or more higher layer parameters indicating parameter K1. Parameter K1 indicates an index in a table specified in the RRC parameters (e.g., via dl-DataToUL-ACK in PUCCH-Config).

[0071] Table 1 depicts an example HARQ-ACK timing indication via parameter dl-DataToUL-ACK in PUCCH-Config below. Table 1 is a non-limiting example of parameters that can be included in the PUCCH configuration. One or more of the parameters can be included. Additionally, the number of bits and choices for each parameter shown in Table 1 are for illustrative purposes only. Other bits or choices can be configured for each parameter that can be included in the PUCCH configuration.

[0072]

[0073] Table 1 Example HARQ-ACK timing indication via parameter dl-DataToUL-ACK in PUCCH-Config

[0074] Figure 2Depicts an example of HARQ-ACK timing indication 200 via parameter dl-DataToUL-ACK in PUCCH-Config. For example, for a slot configuration DDDDU, the HARQ ACK / NACK can be configured such that the ACK / NACK information bits and / or codebook can be multiplexed and transmitted at one or more UL slots by specifying K1.

[0075] Timing indications for transmitting feedback and / or acknowledgments in NR-TDD can result in latency, e.g., because the timing can be based on a semi-static configuration of UL slots. However, considering dynamic TDD, multiple time units can be dynamically configured as UL. Additionally, a sub-band non-overlapping full-duplex (SBFD) scheme can include UL sub-bands within DL time units, thus increasing UL transmission opportunities.

[0076] The latency of PUCCH (e.g., feedback and / or acknowledgment) transmission can be reduced based on opportunistic transmission in UL resources.

[0077] A latency reduction method based on opportunistic acknowledgment transmission can be implemented. An opportunistic acknowledgment transmission based on a sequence can also be implemented, where the sequence selection can be based on the received signal and / or channel. Methods regarding opportunistic HARQ-ACK and group DCI acknowledgments can also be implemented.

[0078] The WTRU can transmit or receive a physical channel or reference signal according to one or more spatial domain filters. The term "beam" can refer to a spatial domain filter.

[0079] The WTRU can use the same spatial domain filter as the one used for receiving an RS (such as CSI-RS) or SS block to transmit a physical channel or signal. The WTRU transmission can be referred to as "target", and the received RS or SS block can be referred to as "reference" or "source". In this case, the WTRU can transmit the target physical channel or signal according to the spatial relationship with such an RS or SS block.

[0080] The WTRU can transmit a first physical channel or signal according to the same spatial domain filter as the one used for transmitting a second physical channel or signal. The first transmission and the second transmission can be referred to as "target" and "reference" (or "source") respectively. The WTRU can transmit the first (target) physical channel or signal according to the spatial relationship with the second (reference) physical channel or signal.

[0081] Spatial relationships can be implicit, configured by RRC, or signaled by MAC CE or DCI. For example, a WTRU can implicitly transmit PUSCH and the DM-RS of the PUSCH according to the same spatial domain filter as the SRS indicated in the DCI or indicated by the SRI configured by RRC. In another example, the spatial relationship can be signaled by an RRC configuration for a sounding reference signal (SRI) or by a MAC CE for a PUCCH. Such a spatial relationship can be referred to as "beam indication".

[0082] A WTRU can receive a first (target) downlink channel or signal according to the same spatial domain filter or spatial reception parameter as a second (reference) downlink channel or signal. For example, such an association can exist between a physical channel (such as a PDCCH or PDSCH) and its corresponding DM-RS. Such an association can exist at least when the first and second signals are reference signals and the WTRU is configured with a quasi-co-location (QCL) assumption type D between corresponding antenna ports. Such an association can be configured as a transmission configuration indicator (TCI) state. The association between a CSI-RS or SS block and a DM-RS can be indicated to the WTRU by an index of a set of TCI states configured by RRC and / or signaled by a MAC CE. Such an indication can also be referred to as "beam indication".

[0083] A TRP (e.g., a transmit and receive point) can be used interchangeably herein with one or more of a TP (transmit point), an RP (receive point), an RRH (radio remote head), a DA (distributed antenna), a BS (base station), a sector of a BS, and a cell (e.g., a geographical cell area served by a BS).

[0084] Multiple TRPs can be used interchangeably herein with one or more of an MTRP, an M-TRP, and / or multiple TRPs.

[0085] The terms "subband" and / or "sub-frequency band" are used herein to refer to frequency domain resources and can be characterized by one or more of a set of resource blocks (RBs), a set of resource block sets (RB sets) (e.g., when a carrier has an in-cell guard band), a set of interleaved resource blocks, a bandwidth part, a bandwidth section, a carrier, or a carrier part.

[0086] For example, a subband can be characterized by a starting RB and the number of RBs for a set of consecutive RBs within a bandwidth part. A subband can also be defined by the value of a frequency domain resource allocation field and a bandwidth part index.

[0087] The term "XDD" is used herein to refer to sub-band level duplexing (e.g., using UL or DL for each sub-band), and can be characterized by one or more of the following. XDD can be characterized by cross-partition duplexing (e.g., sub-band level FDD within a TDD band). XDD can be characterized by sub-band based full duplexing (e.g., full duplex because both UL and DL are used / mixed on a symbol / slot, but UL or DL is used for each sub-band of that symbol / slot). XDD can be characterized by frequency domain multiplexing (FDM) of DL / UL transmissions within a TDD spectrum. XDD can be characterized by sub-band non-overlapping full duplexing (e.g., non-overlapping sub-band full duplex). XDD can be characterized by full duplex other than same frequency (e.g., spectrum sharing, sub-band level overlap) full duplex. XDD can be characterized by advanced duplex methods (e.g., other than (pure) TDD or FDD).

[0088] The term "dynamic ( / flexible) TDD" is used herein to refer to a TDD system / cell that can dynamically (and / or flexibly) change / adjust / switch the communication direction (e.g., downlink, uplink or sidelink, etc.) at time instances (e.g., time slots, symbols, subframes, etc.). For example, in a system employing dynamic / flexible TDD, based on an indication by a group common (GC)-DCI including a time slot format indicator (SFI) (e.g., format 2_0) and / or based on a tdd-UL-DL-config common / dedicated configuration, a component carrier (CC) or a bandwidth part (BWP) can have one type of "D", "U", and "F" on a symbol / slot. At a given time instance / time slot / symbol, a first gNB (e.g., cell, TRP) employing dynamic / flexible TDD can transmit a downlink signal to a first WTRU communicating / associated with the first gNB based on a first SFI configured and / or indicated by the first gNB and / or a tdd-UL-DL-config configuration, and a second gNB (e.g., cell, TRP) employing dynamic / flexible TDD can receive an uplink signal transmitted from a second WTRU communicating / associated with the second gNB based on a second SFI configured and / or indicated by the second gNB and / or a tdd-UL-DL-config. For example, a first WTRU can determine that the reception of a downlink signal is being interfered with by an uplink signal, where the interference caused by the uplink signal can refer to WTRU-to-WTRU cross-link interference (CLI).

[0089] A WTRU may report a subset of channel state information (CSI) components, where the CSI components may correspond to at least a CSI-RS resource indicator (CRI), an SSB resource indicator (SSBRI), an indication of a panel received at the WTRU (such as a panel identifier or a group identifier), measurements obtained from an SSB or CSI-RS such as L1-SRP, L1-SINR (e.g., cri-RSRP, cri-SINR, ssb-Index-RSRP, ssb-Index-SINR), and other channel state information such as at least a rank indicator (RI), a channel quality indicator (CQI), a precoding matrix indicator (PMI), a layer index (LI), etc.

[0090] Authorized or assigned attributes may include one or more of the following. Authorized or assigned attributes may include a frequency allocation. Authorized or assigned attributes may include aspects of a time allocation such as a duration. Authorized or assigned attributes may include a priority. Authorized or assigned attributes may include a modulation and coding scheme. Authorized or assigned attributes may include a transport block size. Authorized or assigned attributes may include a number of spatial layers. Authorized or assigned attributes may include a number of transport blocks. Authorized or assigned attributes may include a TCI state, a CRI, or an SRI. Authorized or assigned attributes may include a number of repetitions. Authorized or assigned attributes may include whether the repetition scheme is type A or type B. Authorized or assigned attributes may include whether the authorization is a configured grant type 1, type 2, or a dynamic grant. Authorized or assigned attributes may include whether the assignment is a dynamic assignment or a semi-persistent scheduling (e.g., configured) assignment. Authorized or assigned attributes may include a configured grant index or a semi-persistent assignment index. Authorized or assigned attributes may include the periodicity of a configured grant or assignment. Authorized or assigned attributes may include a channel access priority class (CAPC). Authorized or assigned attributes may include any parameter for a scheduling authorization or assignment provided in a DCI, by the MAC, or by the RRC.

[0091] Indications made by a DCI may include one or more of the following. Indications made by a DCI may include an explicit indication by a DCI field or by an RNTI used to mask a CRC of a PDCCH. Indications made by a DCI may include an implicit indication of an attribute such as a DCI format, a DCI size, a Coreset or a search space, an aggregation level, and / or a first resource element of a received DCI (e.g., an index of a first control channel element), where a mapping between the attribute and a value may be signaled by the RRC or the MAC.

[0092] The term "signal" may be used interchangeably herein to refer to one or more of a sounding reference signal (SRS), channel state information (e.g., a CSI reference signal (CSI-RS)), a demodulation reference signal (DM-RS), a phase tracking reference signal (PT-RS), and / or a synchronization signal block (SSB).

[0093] The term "RS" may be used interchangeably herein to refer to one or more of an RS resource, an RS resource set, an RS port, and / or an RS port group. The term "RS" may also be used interchangeably herein to refer to one or more of an SSB, a CSI-RS, an SRS, and / or a DM-RS.

[0094] The terms "opportunistic acknowledgment (ACK) transmission" and "single-shot acknowledgment transmission" may be used interchangeably herein.

[0095] Figure 3 is a flowchart illustrating an example opportunistic transmission 300 of an ACK for one or more downlink receptions.

[0096] At 302, the WTRU may receive one or more (e.g., multiple) downlink signals and / or channels. For example, the multiple signals and / or channels may include PDSCH reception, PDSCH release, TCI state, and / or group DCI signals.

[0097] At 304, the WTRU may receive first configuration information that indicates first time and frequency resources for transmitting a hybrid automatic repeat request (HARQ) acknowledgment (ACK) and / or non-acknowledgment (NACK).

[0098] At 306, the WTRU may receive second configuration information that indicates second time and frequency resources for transmitting a HARQ-ACK.

[0099] At 308, the WTRU may receive one or more sequences to be transmitted in the second time and frequency resources. The second configuration information may indicate one or more sequences to be transmitted using the second time and frequency resources.

[0100] The second time and frequency resources may be earlier than (e.g., earlier in time than) the first time and frequency resources. For example, opportunistic transmissions may be based on transmissions of sequences. Accordingly, the WTRU may be configured with one or more sequences to be transmitted in the second time and frequency resources. The one or more sequences may be WTRU-specific (e.g., in the CFRA mechanism). The WTRU may transmit one or more sequences or repetitions of a sequence within the configured time resource. The second time and frequency resources for opportunistic transmissions may be indicated based on one or more of implicit indication, explicit indication, semi-static indication, or dynamic indication. The WTRU may explicitly indicate the time and frequency resources. For example, the gNB may explicitly indicate the time and frequency resources to the WTRU. The gNB may indicate the time and frequency resources based on an association with an SSB index. The WTRU may receive a semi-static indication via an RRC indication. The WTRU may receive a dynamic indication via DCI and / or MAC-CE (e.g., dynamic TDD configuration, dynamic SBFD configuration, etc.). The second time and frequency resources may be cell-specific and may be used per WTRU and / or per WTRU group.

[0101] At 310, the WTRU may determine whether to acknowledge each of a plurality of downlink signals and / or channels. When the WTRU determines that the WTRU has generated a negative acknowledgment for the received corresponding DL signal and / or channel, at 314, the WTRU may not transmit in the second time and frequency resources for opportunistic acknowledgment transmissions. At 316, the WTRU may use the first time and frequency resources for transmission to indicate a negative acknowledgment for one or more of the plurality of downlink signals and / or channels.

[0102] At 312, if the WTRU determines to acknowledge each of the plurality of downlink signals, the WTRU may use the second time and frequency resources to transmit at least one of the one or more sequences, wherein the second time and frequency resources are used to transmit at least one of the one or more sequences to indicate an acknowledgment associated with the plurality of downlink signals (e.g., an acknowledgment for each of the plurality of downlink signals).

[0103] When the WTRU determines that the WTRU has generated an acknowledgment for the received corresponding DL signal and / or channel, the WTRU may determine the sequence to be transmitted. The WTRU may transmit the determined sequence in the second time and frequency resources for opportunistic acknowledgment transmissions. The WTRU may transmit a positive acknowledgment (if configured to do so) in the first time and frequency resources to increase reliability.

[0104] At 316, if the WTRU determines at 310 to send a negative acknowledgment for one or more of the multiple downlink signals, the WTRU may use a first time and frequency resource to transmit the negative acknowledgment, where the first time and frequency resource is used to transmit the negative acknowledgment to indicate the negative acknowledgment for one or more of the multiple downlink signals.

[0105] The gNB may monitor the reception of the sequence in a second time and frequency resource, such as for opportunistic acknowledgment transmission. The gNB may identify the received sequence. The gNB may determine the WTRU based on the received sequence. The gNB may determine that the corresponding DL transmission is acknowledged by the determined WTRU.

[0106] The WTRU may receive a first configuration via higher layer signaling (e.g., RRC and / or MAC-CE) on a first time and / or frequency resource for transmitting an acknowledgment in response to receiving a downlink signal and / or channel (e.g., parameter K1 for HARQ-ACK transmission). The WTRU may receive a downlink signal and / or channel based on a dynamic scheduling grant received based on DCI that may include an indication (e.g., value of parameter K1) associated with the first time and / or frequency resource, or based on a higher layer configuration (e.g., semi-persistent scheduling, configured grant) associated with the first time or frequency resource.

[0107] The WTRU may receive a second configuration via higher layer signaling (e.g., RRC and / or MAC-CE) on a second time and / or frequency resource, such as for opportunistic transmission of an acknowledgment, in response to receiving a downlink signal and / or channel. Compared to the first time and / or frequency resource, the second time and / or frequency resource may indicate an earlier time instance, which may provide a benefit in terms of reducing the latency for delivering the acknowledgment.

[0108] The WTRU may receive multiple downlink signals and / or channels based on a higher layer configuration (e.g., semi-persistent scheduling, configured grant) that may be configured with / associated with a first time and / or frequency resource and / or a second time and / or frequency resource for opportunistic transmission. Based on receiving the higher layer configuration, the WTRU may determine one or more DL actual reception timing instances for receiving the multiple downlink signals and / or channels, where the one or more DL instances are based on periodicity and / or a time offset from a reference time (e.g., frame number / boundary, subframe number / boundary, slot number / boundary, symbol number / boundary, and / or a reference time instance related to a predefined / pre-configured time unit), or based on a time domain pattern (e.g., a regular or irregular pattern in the time domain, a search space configuration for DL monitoring, such as CORESET-based PDCCH monitoring, RS monitoring / measurement, etc.) with respect to the predefined / pre-configured time unit.

[0109] For example, a first time and / or frequency resource may be associated with one or more DL instances, where the WTRU may determine to transmit an acknowledgement at a time instance (e.g., a moment, a timestamp, a time period, a time unit such as a subframe, a slot, a symbol, a set of symbols, a set of slots, etc.) determined based on each of the first time and / or frequency resource and the one or more DL instances. The WTRU may determine that the time instance is one (T1) of the one or more DL instances (T1, T2, T3, ……) plus a K1 value (determined based on the first time and / or frequency resource), and may transmit the acknowledgement at the time instance determined to be T1 + K1.

[0110] A second time and / or frequency resource for opportunistic transmission may be associated with one or more DL instances, where the WTRU may determine an opportunistic transmission of an acknowledgement at a second time instance determined based on each of the second time and / or resource and the one or more DL instances. The WTRU may determine that the time instance is one (T1) of the one or more DL instances (T1, T2, T3, ……) plus a value O1 determined based on the second time and / or frequency resource, and may transmit an opportunistic acknowledgement at the time instance determined to be T1 + O1. In an example, the value of O1 may be less than K1 (e.g., O1 < K1), which may provide a benefit in terms of reducing the latency for transmitting the acknowledgement.

[0111] The value of O1 may be used for more than one DL instance to which the WTRU may be configured and / or instructed to apply (e.g., all of the one or more DL instances for multiple downlink signals and / or channels). The value of O1 may vary according to each of the one or more DL instances to which the WTRU may be configured and / or instructed to apply (e.g., determined independently). For example, the WTRU may transmit an opportunistic acknowledgement at a first time instance determined to be T1 + O1 in response to receiving multiple downlink signals and / or channels at T1, and the WTRU may transmit an opportunistic acknowledgement at a second time instance determined to be T2 + O2 in response to receiving a downlink signal and / or channel at T2, where the WTRU may determine O2 (based on the second time and / or frequency resource) independently of O1.

[0112] For example, the WTRU may determine O1 (e.g., the value of O1) based on a first information content (e.g., a first part / set / combination of resources) of a second time and / or frequency resource (such as based on / dependent on one or more DL reception related parameters associated with T1). The WTRU may determine O2 (e.g., the value of O2) based on a second information content (e.g., a second part / set / combination of resources) of a second time and / or frequency resource (such as based on / dependent on one or more DL reception related parameters associated with T2).

[0113] The WTRU may receive a plurality of downlink signals and / or channels based on receiving DCI (e.g., for dynamic scheduling grant, for indicating a control command via a DCI field, etc.), where the DCI may include a first indication (e.g., first configuration information) associated with a first time and / or frequency resource (the value of parameter K1) and / or a second indication (e.g., second configuration information) associated with a second time and / or frequency resource for opportunistic transmission. Based on receiving the DCI, the WTRU may determine one or more DL actual reception timing instances for receiving the plurality of downlink signals and / or channels, where the one or more DL instances are a single instance of a DL reception indicated / scheduled by the DCI or multiple instances based on repeated DL transmissions (e.g., PDSCH repetition including multiple PDSCH opportunities, multiple RS transmissions, multiple DL transmissions via DCI of a type that is a semi-persistent scheduling (SPS) activation command, etc.).

[0114] For example, the first time and / or frequency resource may be associated with one or more DL instances, where the WTRU may determine to transmit an acknowledgement at a time instance determined based on each of the first time and / or frequency resource and the one or more DL instances. The WTRU may determine that the time instance is one (T1) of the one or more DL instances (T1, T2, T3, ……) plus the value of K1 (determined based on the first time and / or frequency resource), and may transmit an acknowledgement at the time instance determined to be T1 + K1.

[0115] The second time and / or frequency resource for opportunistic transmission may be associated with one or more DL instances, where the WTRU may determine to transmit an opportunistic acknowledgement at a second time instance determined based on each of the second time and / or resource and the one or more DL instances. The WTRU may determine that the time instance is one (T1) of the one or more DL instances (T1, T2, T3, ……) plus the value of O1 determined based on the second time and / or frequency resource, and may transmit an opportunistic acknowledgement at the time instance determined to be T1 + O1. For example, the value of O1 may be less than K1 (e.g., O1 < K1), which may provide a benefit in terms of reducing the latency for transmitting an acknowledgement.

[0116] The WTRU may receive a second indication via the same DCI that indicates the first indication. The WTRU may receive the second indication via the same DCI field of the DCI that indicates the first indication, where the second indication may be implicitly associated with one or more code points and / or other parameters of the same DCI field (e.g., one or more SSB indexes, one or more DL RSs, etc. related to the first indication). The WTRU may receive the second indication via a second DCI field of the DCI that is separate from the first DCI field of the DCI that indicates the first indication. The value of O1 may be used (e.g., in the case of repeated DL transmissions) for more than one DL instance for which the WTRU may be configured and / or indicated to apply (e.g., for all of one or more DL instances for a downlink signal and / or channel). For example, in the case of repeated DL transmissions, the value of O1 may vary (e.g., be determined independently) according to each of one or more DL instances for which the WTRU may be configured and / or indicated to apply. For example, the WTRU may transmit an opportunistic acknowledgment at a first time instance determined to be T1 + O1 in response to receiving a downlink signal and / or channel at T1, and the WTRU may transmit an opportunistic acknowledgment at a second time instance determined to be T2 + O2 in response to receiving a downlink signal and / or channel at T2, where the WTRU may determine the value of O2 independently of the value of O1 (based on the second time and / or frequency resources).

[0117] For example, the WTRU may determine the value of O1 based on a first information content (e.g., a first part / set / combination of resources) of the second time and / or frequency resources (e.g., based on / dependent on one or more DL reception related parameters associated with T1). The WTRU may determine O2 based on a second information content (e.g., a second part / set / combination of resources) of the second time and / or frequency resources (e.g., based on / dependent on one or more DL reception related parameters associated with T2).

[0118] The second time and / or frequency resources for opportunistic transmission may be indicated and / or configured based on an implicit indication and / or an explicit indication. For an explicit indication, the gNB may explicitly indicate the second time and / or frequency resources (e.g., via RRC and / or MAC-CE). For an implicit indication, the gNB may indicate the second time and / or frequency resources based on an association with one or more SSB indexes and / or one or more DLRSs.

[0119] The second time and / or frequency resources for opportunistic transmission may be indicated and / or configured based on a semi-static and / or dynamic indication. The semi-static indication may include an RRC indication and / or a MAC-CE indication and / or activation. The dynamic indication may include DCI and / or MAC-CE (e.g., based on a dynamic TDD configuration, a dynamic SBFD configuration, etc.).

[0120] The second time and / or frequency resources for opportunistic transmission can be indicated and / or configured based on second time and / or frequency resources specific to cell configuration (e.g., via system information messages, MIB, and / or SIB, etc.) and / or specific to WTRU group configuration and / or indication (e.g., via multicast signaling associated with the WTRU group ID, etc.). The second time and / or frequency resources can be used per WTRU and / or per WTRU group.

[0121] Figure 4 An example SBFD configuration 400 is depicted. The second time and / or frequency resources for opportunistic transmission can be indicated and / or configured based on SBFD-related configurations (e.g., UL subband-related configurations / indications in SBFD symbols / slots, XDD symbol / slot configurations, enhanced SFI configurations, enhanced tdd-UL / DL-configuration, and / or advanced duplex-related parameters based on the hybrid DL / UL directions used in symbol / slot configurations at least on the gNB / cell side / angle). For example, compared to a conventional TDD configuration (e.g., DDDFU, which can mean: the 1st slot is DL, the 2nd slot is DL, the 3rd slot is DL, the 4th slot is Flexible, and the 5th slot is UL), the WTRU can receive an SBFD (e.g., XDD) configuration within a given time unit (e.g., slot, symbol) that can convert one or more of the slots into a slot including hybrid UL / DL subbands.

[0122] The WTRU can determine to use one or more slots for SBFD operation. In response to determining to use one or more slots for SBFD operation, the WTRU can convert each of the one or more slots into a slot with hybrid UL / DL subbands. As Figure 4As shown, the WTRU may determine that the second time slot 402 (e.g., time slot n+1), the third time slot (e.g., time slot n+2) 404, and / or the fourth time slot (time slot n+3) 406 may be used for SBFD operations, which includes one or more UL subbands (e.g., a set of RBs). The first time slot 401 of the example SBFD configuration 400 may be a downlink time slot. The second time slot 402 of the example SBFD configuration 400 may be an SBFD time slot with hybrid UL / DL subbands. The third time slot 404 of the example SBFD configuration 400 may be an SBFD time slot with hybrid UL / DL subbands. The fourth time slot 406 of the example SBFD configuration 400 may be an SBFD time slot with hybrid UL / DL subbands. The fifth time slot 408 of the example SBFD configuration 400 may be an uplink time slot. In response to determining that one or more time slots (e.g., time slots 402, 404, 406) are used for SBFD operations, the WTRU may determine that the second time and / or frequency resources for opportunistic transmission may be applicable to the second time slot 402, the third time slot 404, and / or the fourth time slot 406 (e.g., associated with the second time slot 402, the third time slot 404, and / or the fourth time slot 406), where SBFD (e.g., XDD or enhanced duplex over TDD / FDD) operations are applicable, used, and / or may be performed.

[0123] For example, the WTRU may determine that the first time instance as T1+O1 may point to the second time slot 402 which is the earliest possible time slot (or based on preconfigured rules) within the frame (e.g., including 5 time slots as an example) applicable to SBFD. For example, the WTRU may determine that the first time instance as T1+O1 may point to the third time slot 404 which is the second earliest possible time slot (or based on preconfigured rules) within the frame (e.g., including 5 time slots as an example) applicable to SBFD for the WTRU, which may provide benefits in terms of resource utilization efficiency since the gNB may allocate different time / frequency resources for different WTRU assignments.

[0124] The WTRU may determine that the downlink signal and / or channel has not been successfully received, measured, and / or decoded (at least partially) at the WTRU. In response to this determination, the WTRU may generate a negative acknowledgment (e.g., NACK) when receiving the corresponding downlink signal and / or channel, and may determine to report the NACK (e.g., to the gNB). In addition, in response to this determination, the WTRU may not transmit the second UL signal (e.g., for ACK) at the second time instance (e.g., at T1+O1) that may be determined based on the second time and / or frequency resources for opportunistic acknowledgment transmission.

[0125] The WTRU may transmit a first UL signal (e.g., for NACK) at a first time instance determined based on a first time and / or frequency resource (e.g., at T1+K1 which may be later than T1+O1), e.g., in response to determining to transmit a NACK. This may provide a benefit in terms of reliability because the gNB may not receive a second UL signal (e.g., as a predefined, preconfigured, and / or indicated sequence and / or signal for the purpose of conveying an ACK from the WTRU), thereby implicitly meaning NACK, but ultimately later (e.g., after the time of "K1-O1"), the gNB may receive the first UL signal explicitly transmitted from the WTRU at T1+K1, thus ensuring NACK.

[0126] The WTRU may determine that a downlink signal and / or channel has been successfully received, measured, and / or decoded at the WTRU (e.g., based on predefined / preconfigured conditions / rules, for all downlink signals and / or channels or for some of them). In response to this determination, the WTRU may generate an affirmative acknowledgment (e.g., ACK) when receiving the corresponding downlink signal and / or channel, and may determine to report the ACK (e.g., to the gNB). The WTRU may transmit a second UL signal (e.g., for ACK) at a second time instance that may be determined based on a second time and / or frequency resource for opportunistic acknowledgment transmission (e.g., at T1+O1), e.g., in response to determining to transmit an ACK.

[0127] The WTRU may not transmit a third UL signal (e.g., for ACK) at a first time instance at which the WTRU may be configured and / or indicated to transmit (e.g., apply and / or do so) (e.g., at T1+K1 which may be later than T1+O1), and the first time instance may be determined based on a first time and / or frequency resource. This may provide a benefit in terms of latency reduction and resource overhead savings because (e.g., instead of transmitting the third UL signal at T1+K1), the WTRU may transmit a second signal at T1+O1 (e.g., which may be earlier than T1+K1) to reduce the latency of conveying the ACK, and the resources pre-assigned for transmitting the third UL signal may be reused for other purposes (e.g., based on successful reception of the second UL signal at the gNB).

[0128] The WTRU may transmit a third UL signal (e.g., for ACK) at a first time instance at which the WTRU may be configured and / or instructed to transmit (e.g., at T1+K1 which may be later than T1+O1) in response to, for example, determining a transmission ACK, and the first time instance may be determined based on a first time and / or frequency resource. This may provide benefits in terms of reduced latency and increased reliability because although the gNB may receive a second UL signal (e.g., as a predefined / pre-configured and / or instructed sequence and / or signal for the purpose of relaying ACK from the WTRU) to reduce latency, the gNB may also receive, at T1+K1, a third UL signal explicitly transmitted from the WTRU at a later time (e.g., after the "K1-O1" time) to ensure ACK for increased reliability.

[0129] A receiver (e.g., the gNB or a second WTRU) that receives an opportunistic ACK (e.g., a second UL signal) may monitor the reception of a predefined / pre-configured and / or instructed sequence (e.g., the second UL signal) associated with a second time and / or frequency resource for opportunistic acknowledgment transmission. The receiver may identify / determine the received sequence at a reception time instance associated with the second time and / or frequency resource during the reception process. For example, the receiver may identify / determine which one or more WTRUs transmit one or more sequences associated with the second time and / or frequency resource based on one or more parameters for generating each of the one or more sequences at the reception time instance. The one or more parameters may include one or more parameters based on a RACH-related transmission signal (e.g., associated with contention-free random access (CFRA)), one or more parameters for generating a ZC sequence (e.g., root index, cyclic shift, etc.), and / or one or more parameters for generating other types of predefined and / or pre-configured sequences.

[0130] The receiver may identify / determine that the corresponding downlink signal and / or channel is acknowledged by the determined one or more WTRUs. The receiver may send another explicit / implicit DL signal (e.g., even) before the time instance "T1+K1" to acknowledge the reception of the opportunistic ACK (e.g., based on transmitting a new data indication (NDI), a new packet, and / or a new / subsequent DL signal).

[0131] Sequence selection may be based on received DL signals and / or channels (e.g., one or more DL transmissions). The WTRU may be configured with one or more time and frequency resources for opportunistic acknowledgment transmissions. The WTRU may be configured with a first sequence (S1) for opportunistic acknowledgment transmissions (e.g., UE-specific root index (r1), cyclic shift (c1), etc.). The WTRU may determine a set of sequences with a specific acknowledgment pattern for the sequence to be used (e.g., S = {S1, S2, S3, ……, SN}), where N is the maximum number of sequences per set.

[0132] The WTRU may determine the set of sequences based on the configured first sequence (S1). The sequences in the set may include cyclic shifts determined based on the first cyclic shift (c1) and / or the first offset value (d) (e.g., for the second sequence (S2), c2 = c1 + d, for the third sequence (S3), c3 = c1 + 2*d, and so on). The WTRU may determine to select a sequence from the set of sequences based on the PDCCH monitoring occasion and transmit.

[0133] If the total DAI (mtotal-DAI) is provided, the WTRU may select the sequence corresponding to the total DAI detected up to the last PDCCH monitoring occasion. The WTRU may increment a counter for each detected PDCCH monitoring occasion. The WTRU may select the sequence corresponding to the total counter value. If no PDCCH monitoring occasion is detected, the WTRU may select the first sequence S1. If the first value of the detected PDCCH monitoring occasion (e.g., one) and / or if the total DAI is equal to the first value (e.g., one), the WTRU may select the second sequence S2.

[0134] The gNB may monitor the reception of sequences in the time and frequency resources for opportunistic acknowledgment transmissions. The gNB may identify one or more received sequences. The gNB may determine the acknowledgment pattern. The gNB may determine whether one or more (e.g., all) PDCCH transmissions have been received, determined, and / or acknowledged.

[0135] For example, the WTRU may report and / or indicate feedback and / or acknowledgment of the reception of one or more configured and / or indicated DL signals and / or channels based on transmitting one or more sequences in the time and frequency resources configured and / or indicated for opportunistic acknowledgment transmissions.

[0136] The WTRU may receive configuration and / or indication of parameters to generate one or more sequences. For example, the sequence may be based on the Zadoff-Chu (ZC) sequence, where the WTRU may receive the root index and cyclic shift. The sequence parameters may be WTRU-specific (e.g., to enable contention-free detection of the sequence at the gNB).

[0137] For example, the WTRU may be configured, instructed, and / or determined that the transmission of one or more configured sequences should be repeated one or more times in the configured, indicated, and / or determined time resources. For example, if the time resource is greater than a first value (e.g., one symbol), the WTRU may determine the repeated sequence transmission based on the number of configured symbols.

[0138] For example, the WTRU may receive an indication of a sequence based on an explicit indication and / or an implicit indication. For example, the WTRU may be configured with one or more sequences, where (e.g., via the gNB) the sequence parameters (e.g., root index and / or cyclic prefix) are explicitly indicated. For example, the WTRU may be configured with one or more sequences, where (e.g., via the gNB) an indication (e.g., only an indication) of the sequence parameters (e.g., root index and / or cyclic prefix) is given for one of the sequences (e.g., the reference sequence) in the sequence. Thus, the WTRU may determine the sequence parameters of other sequences based on the configured reference sequence and one or more (pre)defined and / or (pre)configured rules. For example, the cyclic prefix of other sequences may be determined based on adding a (pre)configured offset value to the cyclic shift configured for the reference sequence. Additionally or alternatively, the WTRU may be configured to determine the reference sequence based on one or more other parameters. For example, the reference sequence may be indicated based on the sequence for contention-free radio access (CFRA).

[0139] The WTRU may receive the configuration of the sequence to be used based on a semi-static configuration. For example, the sequence may be indicated as part of the channel access parameters, SPS PDSCH configuration, TDD configuration, etc. Alternatively, the WTRU may receive a dynamic indication of the sequence based on a dynamic indication. For example, a dynamic grant DCI, SFI, or dynamic sub-band full-duplex (SBFD) indication may be used for the indication of the sequence.

[0140] The sequence selection may be based on the received DL signal and / or channel. When the WTRU is configured with SPS PDSCH or DG-PDSCH, the HARQ-ACK process index may be indicated. Thus, when the WTRU transmits a positive acknowledgement, the positive acknowledgement may mean that one or more (e.g., all) possible HARQ-ACK processes are acknowledged. However, in the case of PDCCH reception (e.g., for TCI state update, SPS PDSCH release, group common DCI, etc.), the WTRU may not be able to know in advance all possible occasions. Thus, the WTRU may not be able to know whether one or more PDCCHs are discarded and / or not received.

[0141] For example, a WTRU may determine and / or be configured or instructed to generate a HARQ-ACK codebook, where the codebook indication is based on one or more sequences. For example, instead of separately generating a set of first and second values (e.g., 0 or 1) for indicating NACK or ACK, the WTRU may be configured with one or more sequence indices that can be used as an index for a set of ACK / NACK patterns and / or scenarios in the corresponding codebook.

[0142] For example, a WTRU may be instructed or configured to receive one or more PDSCH downlink transmissions. The WTRU may use the total DAI field in the UL grant DCI to determine the total number of TBs or CBGs to be received. Additionally or alternatively, the WTRU may determine the total number of TBs or CBGs to be received based on the received configuration and / or grant DCI indication.

[0143] For example, if the WTRU determines that one or more (e.g., all) PDSCH codewords (e.g., the expected PDSCH codewords) are correctly received, the WTRU may generate and / or determine a first sequence (e.g., S1) from the codebook. The WTRU may transmit the first sequence at the configured time and frequency for opportunistic acknowledgment transmission.

[0144] For example, the WTRU may determine the total number of control signals and / or channels in the downlink reception (e.g., PDCCH) based on the number of detected occasions. Thus, the WTRU may determine the sequence to be used associated with the total number of received control signals and / or channels based on the corresponding index in the respective codebook. Additionally or alternatively, if the WTRU has detected a specific pattern of control signals and / or channels, the WTRU may select a sequence index from the codebook corresponding to the detected pattern and / or scenario. The number of codebook entries may be restricted (e.g., at most N+1 sequences, which means a maximum of N patterns for receiving control signals and / or channels).

[0145] For example, if the WTRU has detected (e.g., only detected) a single DCI, the WTRU may determine to select a second sequence (e.g., S2) from the codebook associated with the detected pattern and / or scenario. The WTRU may then transmit the selected sequence at the configured time and frequency resources for opportunistic acknowledgment transmission. If the WTRU has detected two DCIs, the WTRU may determine to select a third sequence (e.g., S3) and transmit the third sequence at the configured time and frequency resources for opportunistic acknowledgment transmission.

[0146] The gNB may monitor the time and frequency resources configured for opportunistic acknowledgment to receive one or more sequences. After successfully detecting a sequence, the gNB may determine the corresponding WTRU and the index of the codebook entry based on the detected sequence.

[0147] Figure 5 depicts an example opportunistic HARQ-ACK transmission 500. The WTRU may receive one or more (e.g., multiple) downlink signals and / or channels (e.g., PDSCH reception, PDSCH release, TCI state, group WTRU identity) 502. The group WTRU identities 504A, 504B may include a G-RNTI for group DCI. The WTRU may receive (e.g., via K1) one or more slot timing values for transmitting HARQ-ACK information bits 506. The WTRU may receive one or more time and frequency resources for opportunistic HARQ-ACK transmissions 508A, 508B (e.g., semi-static or dynamic, implicit or explicit). For example, the one or more time and frequency resources for opportunistic HARQ-ACK transmissions 508A, 508B may be received via group DCI. The WTRU may receive multiple downlink transmissions 502. The WTRU may receive one or more sequences via opportunistic HARQ-ACK transmissions 508A, 508B to indicate group ACK / NACK (e.g., S1 for group ACK, S2 for group NACK, etc.). For example, the WTRU may receive one or more sequences via SIB, RRC, MAC-CE, and / or DCI. The configuration of the one or more sequences may be cell-common or WTRU-specific. Additionally or alternatively, the WRU may receive one or more sequences as part of the configuration of a second resource. The WTRU may determine HARQ-ACK message bits 510, a total of O ACK HARQ-ACK information bits (e.g., for all serving cells, HARQ processes, TBs, CBGs, group DCIs, etc.).

[0148] The WTRU may set where & represents the binary AND operator 512. The WTRU may determine which sequence to transmit to indicate ACK or NACK. When Total-Ack is a positive ACK (e.g., value of 1), the WTRU may use the determined sequence to transmit a single Ack and may transmit in the configured and / or determined opportunistic resources. The WTRU may determine which of the HARQ-ACK information bits 510A, 510B is associated with a positive acknowledgement or a negative acknowledgement. When the WTRU determines that each of the HARQ-ACK information bits 510A, 510B is associated with a positive acknowledgement, the WTRU may determine that Total-Ack is a positive ACK. When one or more of the HARQ-ACK information bits 510A, 510B is associated with a negative acknowledgement, the WTRU may determine that Total-ACK is negative.

[0149] When Total-ACK is negative (e.g., one or more NACKs), the WTRU may set where | represents the binary OR operator (e.g., if the data was not received correctly, OP-NACK state = 1). When Total-NACK is positive (e.g., equal to 1), the WTRU may determine the sequence to transmit for a single NACK (e.g., or use a configured sequence), and transmit that sequence in the configured and / or determined opportunistic resources. For example, the WTRU may use the first time and frequency resource 508A to indicate a positive Total-Ack using at least one of one or more sequences. For example, the WTRU may use the time and frequency resource 508A to indicate the ACK for each of the plurality of downlink signals 502. The WTRU may use the second time and frequency resource 508B to indicate a positive Total-NACK. For example, the WTRU may use the time and frequency resource 508B to indicate the NACK for at least one of the plurality of downlink signals 502.

[0150] Otherwise (e.g., Total-ACK equals 0 and Total-NACK equals 0, indicating that some of the data was received correctly and some was not), the WTRU may not transmit in the configured and / or determined opportunistic resources. Thus, the WTRU may wait until the HARQ-ACK transmission occasion (e.g., determined by K1) to transmit the corresponding HARQ-ACK codebook.

[0151] The gNB may monitor the reception of the sequence in the time and frequency resources used for opportunistic HARQ-ACK transmission. If the gNB identifies the transmitted sequence, the gNB may determine the WTRU based on the received sequence, and the gNB determines that the determined WTRU acknowledges the corresponding DL transmission. Additionally or alternatively, the gNB may identify one or more WTRUs that have not received the group DCI (e.g., the sequence configured for the WTRU was not detected). The gNB may retransmit the group DCI and / or decide to send the information and / or command in another way (e.g., send a dedicated DCI to each involved WTRU, send the information via another means such as a MAC CE or an RRC reconfiguration message, etc.).

[0152] A WTRU may receive one or more downlink signals and / or channels. The WTRU may receive one or more configured to generate one or more HARQ-ACK information bits and / or HARQ-ACK codebooks based on, for example, one or more downlink signals and / or channels. For example, the WTRU may report HARQ-ACK information for one or more PDSCH receptions, PDCCH (e.g., DCI) receptions, TCI state updates, PDSCH without a corresponding PDCCH received, PDCCH indicating SPS PDSCH release, etc. The WTRU may report the HARQ-ACK information bits in a HARQ-ACK codebook (e.g., type 1, type 2, type 3, etc.) transmitted by the WTRU in a time slot indicated by a timing indicator (e.g., PDSCH to HARQ feedback timing indicator field in the corresponding DCI format). For example, the WTRU may be configured to transmit a first sequence in a set of sequences based on the HARQ-ACK feedback to be reported for the downlink signal and / or channel. For example, the WTRU may be configured to transmit a second sequence in a set of sequences based on the HARQ-ACK feedback to be reported for the downlink signal and / or channel. The WTRU may be configured to transmit at least one indication of ACK and at least one indication of NACK based on the HARQ-ACK feedback to be reported for the downlink signal and / or channel, using a first time and frequency resource based on at least one of the time slot timing values, to indicate the HARQ-ACK for the downlink signal. The WTRU may determine whether the resource for HARQ-ACK reporting is mapped to the PUCCH or the PUSCH.

[0153] The WTRU may determine HARQ-ACK information bits, for a total of O ACK HARQ-ACK information bits. For example, the WTRU may be configured to determine the HARQ-ACK information bits for each of a plurality of downlink signals. The WTRU may be configured with one or more HARQ-ACK codebook indices for multiplexing the corresponding HARQ-ACK information bits (e.g., according to the SPS PDSCH configuration).

[0154] The WTRU may receive, determine, and / or be configured with opportunistic acknowledgment (OP-ACK) transmission. If the WTRU is configured with OP-ACK, the WTRU may receive an indication to report OP-ACK (e.g., via RRC, MAC-CE, DCI).

[0155] The WTRU may receive in the OP-ACK (e.g., a set of information bits OP ACK) includes an indication of one or more ACK / NACKs (e.g., information bits), e.g., to generate and report an OP-ACK for one or more of the following. The parameters and configurations are non-limiting examples of parameters that can be used to generate OP-ACK information bits. One or more of these parameters can be included, and other parameters can be included. One or more HARQ processes and one or more component carriers (CCs) configured in a corresponding PUCCH group. One or more SPS PDSCH receptions configured for one or more serving cells, in one or more active BWPs, on one or more DL time slots for SPS PDSCH reception (e.g., configured to be multiplexed in a corresponding PUCCH). One or more CBG-level ACK / NACKs for each CC configured with CBG-level transmission. One or more configured (e.g., SPS) PDSCH receptions, SPS PDSCH releases, or TCI state updates. One or more group DCI formats (e.g., having a CRC scrambled by a G-RNTI or G-CS-RNTI and / or high-priority group DCI). Detection of one or more DCI formats (e.g., providing a TCI state update) when PDSCH reception is not scheduled.

[0156] Additionally or alternatively, the WTRU can receive an indication not to include CBG-level ACK / NACKs in the OP-ACK. Thus, even if CBG-level transmission is configured for a CC, the WTRU can report TB-level ACK / NACKs in the OP-ACK. The WTRU can receive an indication of the number of serving cells and / or the number of HARQ processes for each indicated serving cell in order to report the OP-ACK.

[0157] For example, a WTRU may receive one or more sequences for OP-ACK reporting. The sequences may be based on Zadoff-Chu sequences, where one or more parameters (e.g., root index and / or cyclic shift) may be configured, indicated, and / or determined. Additionally or alternatively, in addition to (e.g., predefined) rules for generating and / or determining other sequences (e.g., based on a reference sequence), the WTRU may also be configured with parameters for generating a sequence (e.g., a reference sequence). The WTRU may determine to select, use, and transmit one or more of the configured sequences based on the configuration use cases of OP-ACK. The sequences may be configured based on one or more of the following. The sequences may be configured based on the OP-ACK configuration. For example, the WTRU may receive parameters for generating and / or determining one or more sequences based on one or more parameters in the OP-ACK configuration and / or indication. The sequences may be configured based on the channel access configuration. For example, the WTRU may receive parameters for generating and / or determining one or more sequences based on one or more parameters received as part of a channel access procedure (e.g., initial access or non-initial access). The sequences may be configured based on DCI indication. For example, the WTRU may receive parameters for generating and / or determining one or more sequences based on one or more parameters received in DCI format.

[0158] For example, the WTRU may receive a configuration and / or indication to use or not use one or more of the sequences that have been configured for other WTRU behavior procedures (e.g., contention-free RACH (CFRA)). The indication may be a flag indication, where one value (e.g., 0) indicates not to use the indicated sequence and another value (e.g., 1) indicates to use the indicated sequence.

[0159] For example, the WTRU may be indicated and / or configured with one or more time and frequency resources for transmitting the determined sequence for OP-ACK indication and / or reporting. The time resources may include one or more symbols. Thus, the WTRU may be configured to repeat sequence transmission over the time domain. The indication and / or configuration of the time and frequency resources for opportunistic acknowledgment transmission may be cell-specific or WTRU-specific received (e.g., via SIB, RRC, MAC-CE, DCI). The WTRU may receive a configuration indicating the sequence index and / or parameters and the indication of the time and frequency resources (e.g., via PDCCH). For example, the time and frequency resources may be configured based on an association with one or more parameters (e.g., based on the SS / PBCH index). The DCI format may trigger an indication for opportunistic acknowledgment transmission, where the time and frequency resources are indicated. The group DCI may indicate the time and frequency resources for opportunistic acknowledgment transmission as part of the indication. The SFI for dynamic TDD indication may indicate the time and frequency resources for opportunistic acknowledgment transmission as part of the indication. The configuration and / or indication for sub-band non-overlapping full duplex (SBFD) may indicate the time and frequency resources for opportunistic acknowledgment transmission.

[0160] The indication and / or configuration of the OP-ACK time and frequency resources are non-limiting examples that may be used for reporting and / or indicating OP-ACK. One or more of these configurations and / or indications may be included. Other configurations and / or indications may be included.

[0161] The WTRU may also receive the HARQ ACK / NACK timing for the received signal and / or channel, and the HARQ ACK / NACK timing may be configured and / or indicated by one or more higher layer parameters (e.g., indicating parameter K1). For example, parameter K1 indicates an index in a table specified in the RRC parameters for fallback HARQ-ACK transmission (e.g., via dl-DataToUL-ACK in PUCCH-Config). Thus, the WTRU transmitting in the OP-ACK time and frequency resources may also transmit one or more indication, configuration, and / or determined HARQ-ACK information bits and / or codebooks (e.g., for reliability issues) in the time and frequency resources indicated by K1.

[0162] For example, according to the received OP-ACK configuration, the WTRU may determine the number of HARQ-ACK information bits for OP-ACK transmission in the time and frequency resources configured and / or indicated for opportunistic acknowledgment transmission, for a total of O OP，ACK number of HARQ-ACK information bits. The total number of HARQ-ACK bits O OP，ACKIt may be indicated and / or configured for a WTRU, or may be determined by the WTRU based on the received OP-ACK configuration.

[0163] The WTRU may determine HARQ-ACK information bits for the serving cell, CC, HARQ process, TB, CBG, etc. for all indications and / or configurations.

[0164] The WTRU may generate a set of all HARQ-ACK information bits determined for OP-ACK reporting based on the received OP-ACK configuration (e.g., ).

[0165] The WTRU may determine the opportunistic ACK (OP-ACK) state based on the determined HARQ-ACK information bits. For example, the WTRU may determine the OP-ACK state based on the generated and / or determined set of OP-ACK information bits (e.g., OP ACK ). Thus, the OP-ACK state may be determined via a binary AND operation of all OP-ACK information bits determined in the OP-ACK set. One or more of the following OP-ACK states may apply. State #0 may indicate all ACKs. In State #0 (e.g., all ACKs), the WTRU may determine that the indications and information bits in the OP-ACK set indicate that all configurations, indications, and / or determined acknowledgments are affirmative. Thus, no negative acknowledgments (e.g., no NACKs) are detected in the OP-ACK set. In State #1 (e.g., all NACKs), the WTRU may determine that the indications and information bits in the OP-ACK set indicate that all configurations, indications, and / or determined acknowledgments are negative. Thus, no affirmative acknowledgments (e.g., no ACKs) are detected in the OP-ACK set. In State #2 (e.g., all PDSCH ACKs), the WTRU may determine that the indications and information bits in the OP-ACK set indicate that all configured and / or indicated PDSCH receptions have been received and the corresponding HARQ-ACK information bits are all affirmative (e.g., value 0). Thus, no negative acknowledgments (e.g., value 0) for the configured or indicated PDSCH reception are detected in the OP-ACK set. In State #3 (e.g., group DCI ACK), the WTRU may determine that the indications and information bits in the OP-ACK set indicate that one or more group DCI signals have been received and may determine and / or confirm the corresponding reception. Thus, no negative acknowledgments for the received configured or indicated group DCI are detected in the OP-ACK set. In State #4 (e.g., non-consistent state), the WTRU may determine that the indications and information bits in the OP-ACK set indicate that some of the configured, indicated, and / or determined acknowledgments are affirmative and some are negative. Thus, there is no consistent acknowledgment state in the OP-ACK set.

[0166] The WTRU may determine a first or second sequence to be transmitted based on an opportunistic ACK state (e.g., the value of the opportunistic ACK state). For example, the WTRU may be configured or may determine to use one or more OP-ACK sequences based on the OP-ACK configuration and the determined OP-ACK state. For example, if the WTRU has determined that the OP-ACK state is state #0, the WTRU may determine to transmit a first sequence (e.g., S1) in the OP-ACK time and frequency resources. Additionally or alternatively, if the WTRU has determined that the OP-ACK state is state #1, state #2, or state #3, the WTRU may determine to transmit a second sequence, a third sequence, or a fourth sequence (e.g., S2, S3, S4) in the OP-ACK time and frequency resources. For example, if the WTRU has determined that the OP-ACK state is state #4, the WTRU may determine not to transmit any sequence in the OP-ACK time and frequency resources.

[0167] Return Figure 5 , which shows an example opportunistic HARQ-ACK transmission 500. One or more WTRUs may receive one or more downlink signals and / or channels 502 (e.g., PDSCH reception, PDSCH release, TCI state). One or more WTRUs may receive (e.g., via K1) one or more slot timing values 506 for transmitting HARQ-ACK information bits. One or more WTRUs may receive one or more time and frequency resources for opportunistic HARQ-ACK transmission (e.g., semi-static or dynamic, implicit or explicit). One or more WTRUs may receive a WTRU-specific sequence at the opportunistic HARQ-ACK transmission resource to indicate (e.g., single-shot) ACK / NACK. For example, WTRU1 may be configured with sequence S1,1 for single-shot ACK transmission and sequence S1,2 for single-shot NACK transmission. For example, WTRU2 may be configured with sequence S2,1 for single-shot ACK transmission and sequence S2,2 for single-shot NACK transmission.

[0168] The WTRU determines relative to the DL signal and / or channel received by the WTRU HARQ-ACK information bits, for a total of O ACK HARQ-ACK information bits. Each WTRU determines its corresponding OP-ACK state (e.g., where & represents the binary AND operator). For example, when the OP-ACK state of the first WTRU is equal to a first value (e.g., 1), the first WTRU determines the sequence to be transmitted (or uses the configured sequence) for single-shot ACK and transmits that sequence in the configured and / or determined opportunistic resources.

[0169] For example, in the case where the OP-ACK state of the first WTRU is equal to a second value (e.g., 0) (e.g., one or more NACKs), the first WTRU determines the OP-NAK state (e.g., = where | represents the binary OR operator), (e.g., if the data is not received correctly, then the OP-NAK state = 1). In the case where the OP-NACK state is equal to 1, the WTRU determines the sequence to be transmitted for a single NACK (or uses a configured sequence) and transmits the sequence in the configured and / or determined opportunistic resources.

[0170] Otherwise (the OP-ACK state is equal to 0 and the OP-NACK state is equal to 0, indicating that some of the data is received correctly and some is not), the WTRU does not transmit in the configured and / or determined opportunistic resources. Therefore, the WTRU waits until the HARQ-ACK transmission occasion (e.g., determined by K1) to transmit the corresponding HARQ-ACK codebook.

[0171] The gNB monitors the reception of the sequence in the time and frequency resources for opportunistic HARQ-ACK transmission. If the gNB identifies the transmitted sequence, the gNB determines the WTRU based on the received sequence. If the gNB detects the sequence corresponding to the OP-ACK state, the gNB determines that the corresponding DL transmission is acknowledged by the determined WTRU. Alternatively, if the gNB detects the sequence corresponding to the OP-NACK state, the gNB determines that none of the corresponding DL transmissions are acknowledged by the determined WTRU. For example, if the network has sufficient resources, the network can retransmit (e.g., blind retransmission) some or all of the blocks before K1 arrives and / or before the gNB knows which are NACKed and which are ACKed.

[0172] The opportunistic group DCI can indicate an acknowledgment transmission. For example, it may be necessary to send group commands to a large number of WTRUs to reduce signaling and latency. As an example, the group command can be a group DCI command that causes the WTRU to trigger certain actions such as handover. For example, in the context of network energy saving, the network can decide to turn off a certain cell or sector of a base station and may wish to notify the WTRUs served by that cell to perform a handover (e.g., handover to a pre-configured candidate cell, similar to conditional handover, but in this case, the handover is triggered when the WTRU receives the group DCI). For example, the network can wait for a specific duration after sending the group DCI (e.g., give the WTRU enough time to perform the HO) before turning off the involved cell / sector.

[0173] Another example is a mobile node that serves as a relay for a WTRU within a vehicle, such as a mobile integrated access backhaul (IAB) installed on a moving vehicle. When the vehicle moves, the IAB node may need to migrate to another serving base station, thereby triggering a handover of all the WTRUs it serves simultaneously. Instead of performing HO signaling to each WTRU individually and having each WTRU perform HO sequentially, which is inefficient from a signaling perspective and may also cause problems (e.g., HO command delays for some WTRUs may result in HO failures), a group DCI that triggers HO for all WTRUs can be used.

[0174] The group DCI message may be relatively more important than other DCI messages because the group DCI message targets multiple WTRUs, and if the group DCI message is used to indicate something like a group HO command, WTRUs that may not have received the group DCI message correctly may ultimately experience radio link failure (e.g., for the case of the above network energy saving scenario). Therefore, a mechanism is needed to enable the network to receive an acknowledgement from the WTRU for receiving such DCI.

[0175] Figure 6 An example opportunistic acknowledgement transmission 600 for high-priority DCI is depicted. A set of WTRUs is configured with a group WTRU identity (e.g., a G-RNTI for group DCI) 602. Each WTRU within the set of WTRUs (e.g., the group) may be configured with a set of sequences (e.g., WTRU1 is configured with a first sequence S1, WTRU2 is configured with a second sequence S2, …, the Nth WTRU is configured with the Nth sequence SN) for opportunistic acknowledgement transmission 604 related to a group DCI (e.g., each sequence having a WTRU-specific root index (r1), cyclic shift (c1), etc.) for a received group DCI command. The WTRU may receive one or more time and frequency resources for opportunistic acknowledgement transmission (e.g., semi-static, dynamic, implicit, or explicit) 606. The WTRU may detect the group DCI in the PDCCH (e.g., DCI scrambled by the associated group WTRU identity). The WTRU may transmit a configured sequence for acknowledging (ACK) 604 the group DCI in the configured and / or determined opportunistic resources 606.

[0176] After transmitting the group DCI, the gNB may monitor the reception of one or more sequences in the time and frequency resources used for opportunistic acknowledgment (e.g., HARQ-ACK) transmission regarding the group DCI. The gNB may identify the WTRUs that have not received the group DCI (e.g., the sequences configured for the WTRU are not detected). The gNB may retransmit the group DCI or decide to transmit the information / command in another way (e.g., transmit dedicated DCI to each involved WTRU, transmit information via another means such as MAC CE or RRC reconfiguration message, etc.).

[0177] It should be understood that although Figure 6 the example shown illustrates the group DCI, this example can be used for any DCI (e.g., high-priority DCI sent to only one WTRU).

[0178] It should be understood that the group ACK for group HARQ-ACK transmission described herein can be combined with the group DCI HARQ mechanism described herein. For example, the WTRU may be configured with multiple sequences: Sa, indicating that all content (e.g., all transport blocks and the group DCI) has been correctly received; Sb, indicating that one or more (e.g., all) transport blocks have been correctly received but the group DCI has not been received (e.g., all transport blocks and the group DCI); Sc, indicating that each transport block has been incorrectly received and the group DCI has not been received either; Sd, indicating that each transport block has been incorrectly received but the group DCI has been received; and / or Sf, indicating that some transport blocks have been incorrectly received but the group DCI has been received.

[0179] The WTRU may indicate the reception of the group DCI and the reception of other transport blocks simultaneously. Moreover, just because some transport blocks before the reception of the group DCI have not been correctly received, the WTRU will not be restricted from using the opportunistic resources to indicate the reception of the group DCI without having to wait for K1 time slots after the reception of the group DCI (e.g., as in normal HARQ-ACK). Additionally, if the group DCI indicates HO, the WTRU may immediately perform HO without waiting for K1 time slots to send the ACK (e.g., immediately stop monitoring the control channel of the source cell and start synchronizing with the target cell).

Claims

1. A wireless transmit / receive unit (WTRU), comprising: a transceiver; and a processor configured to: receive a plurality of downlink signals via the transceiver; receive, via the transceiver, first configuration information indicating first time and frequency resources for transmitting hybrid automatic repeat request (HARQ) acknowledgments (ACKs); receive, via the transceiver, second configuration information indicating second time and frequency resources for transmitting HARQ-ACKs, wherein the second configuration information indicates one or more sequences to be transmitted using the second time and frequency resources; and transmit, via the transceiver, at least one of the one or more sequences using the second time and frequency resources, wherein transmitting the at least one of the one or more sequences using the second time and frequency resources indicates an ACK associated with the plurality of downlink signals.

2. The WTRU according to claim 1, wherein the processor is further configured to transmit, via the transceiver, a negative ACK (NACK) associated with the plurality of downlink signals using the first time and frequency resources.

3. The WTRU according to claim 2, wherein the NACK associated with the plurality of downlink signals is transmitted at a time instance determined based on the first time and frequency resources.

4. The WTRU according to any one of claims 1 to 3, wherein the second time and frequency resources include an uplink subband within a subband non-overlapping full duplex (SBFD) download time unit.

5. The WTRU according to any one of claims 1 to 4, wherein the second time and frequency resources are indicated by one or more of implicit indication, explicit indication, semi-static indication, and dynamic indication.

6. The WTRU according to any one of claims 1 to 5, wherein the second time and frequency resources are cell-specific.

7. The WTRU according to any one of claims 1 to 6, wherein the second time and frequency resources indicate an earlier time instance compared to the first time and frequency resources.

8. The WTRU according to any one of claims 1 to 7, wherein the plurality of downlink signals are received based on a higher layer configuration associated with the first time and frequency resources or the second time and frequency resources.

9. The WTRU according to any one of claims 1 to 8, wherein the at least one of the one or more sequences is transmitted at a time instance determined based on the second time and frequency resources.

10. The WTRU according to any one of claims 1 to 9, wherein the second time and frequency resources are associated with a time slot within a subband non-overlapping full duplex (SBFD) resource block.

11. A method performed by a wireless transmit / receive unit (WTRU), the method comprising: receiving a plurality of downlink signals; receiving, via a transceiver, first configuration information indicating first time and frequency resources for transmitting hybrid automatic repeat request (HARQ) acknowledgments (ACKs); Receiving second configuration information via the transceiver indicating a second time and frequency resource for transmitting HARQ-ACK, wherein the second configuration information indicates one or more sequences to be transmitted using the second time and frequency resource; and Using the second time and frequency resource to send at least one of the one or more sequences, wherein using the second time and frequency resource to transmit the at least one of the one or more sequences to indicate an ACK associated with the plurality of downlink signals.

12. The method according to claim 11, further comprising using the first time and frequency resource to send a negative ACK (NACK) associated with the plurality of downlink signals.

13. The method according to claim 12, wherein the NACK associated with the plurality of downlink signals is transmitted at a time instance determined based on the first time and frequency resource.

14. The method according to any one of claims 11 to 13, wherein the second time and frequency resource comprises an uplink subband within a subband non-overlapping full-duplex download time unit.

15. The method according to any one of claims 11 to 14, wherein the second time and frequency resource is indicated by one or more of implicit indication, explicit indication, semi-static indication, and dynamic indication.

16. The method according to any one of claims 11 to 15, wherein the second time and frequency resource is cell-specific.

17. The method according to any one of claims 11 to 16, wherein the second time and frequency resource indicates an earlier time instance compared to the first time and frequency resource.

18. The method according to any one of claims 11 to 17, wherein the plurality of downlink signals are received based on a higher layer configuration that can be associated with the first time and frequency resource or the second time and frequency resource.

19. The method according to any one of claims 11 to 18, wherein the at least one of the one or more sequences is transmitted at a time instance determined based on the second time and frequency resource.

20. The method according to any one of claims 11 to 19, wherein the second time and frequency resource is associated with a time slot within a subband non-overlapping full-duplex (SBFD) resource block.

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