Transmission adaptation and grant-free access

Abstract

To provide systems disclosed for transmission adaptation and grant-free access in an unlicensed band.SOLUTION: A wireless transmit / receive unit (WTRU) may receive a set of candidate resources that may be used for transmission. The WTRU may periodically perform CCA on a channel (e.g., before transmitting on the channel). When the channel is determined to be free, the WTRU may determine a resource for transmission from the candidate resources. The resource may be determined on the basis of a time remaining in a time period. For example, when the time remaining in the time period is shorter, the WTRU may determine to transmit on a resource that comprises more frequency resources. The WTRU may determine a Multiple Input Multiple Output (MIMO) scheme on the basis of the number of frequency resources. The WTRU may send a transmission on the determined resource, which may include a demodulation reference signal (DM-RS). The DM-RS may indicate the resource used for transmission to a receiver of the transmission.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority from U.S. Provisional Patent Application No. 62 / 500,533, filed May 3, 2017, which is incorporated herein by reference in its entirety. [Background technology]

[0002] Mobile communications continue to evolve. The fifth generation is sometimes referred to as 5G. The previous (legacy) generation of mobile communications can be, for example, fourth generation (4G) Long Term Evolution (LTE). Mobile wireless communications implement various radio access technologies (RATs), such as new radio (NR). Use cases for NR can include, for example, extreme mobile broadband (eMBB), ultra-reliable low-latency communications (URLLC), and massive machine-type communications (mMTC). Summary of the Invention

[0003] Systems, methods, and means are disclosed for transmission adaptation and grant-free access, for example, in unlicensed bands. Flexible transmission boundaries can be provided for transmission adaptation (e.g., time periods and / or time units). A grant-free access resource pool can be provided. Unlicensed operation can be provided in beam-based systems, for example, using resource pools and / or clear channel assessment (CCA).

[0004] A wireless transmit / receive unit (WTRU) may receive an indication and / or set of candidate resources that may be used for transmission. The WTRU may periodically perform CCA on a channel (e.g., before transmitting on the channel) to determine whether the channel is free for transmission. If the channel is determined to be free, the WTRU may determine a resource for transmission (e.g., in this case, the resource may refer to one or more time and / or frequency resources) from the candidate resources. The resource may be determined based on the time remaining in a time period. For example, if there is less time remaining in a time period, the WTRU may determine to transmit on a resource that includes more frequency resources. The WTRU may determine a multiple-input multiple-output (MIMO) scheme based on the number of frequency resources used for the transmission. The WTRU may send a transmission using the determined resource, and the transmission may include a demodulation reference signal (DM-RS). The DM-RS may indicate to a receiver of the transmission the resource used for the transmission. [Brief explanation of the drawings]

[0005] [Figure 1A] FIG. 1 is a system diagram of an example communication system in which one or more disclosed embodiments may be implemented. [Figure 1B] 1B is a system diagram of an example wireless transmit / receive unit (WTRU) that may be used within the communication system illustrated in FIG. 1A. [Figure 1C] 1B is a system diagram of an example radio access network (RAN) and an example core network (CN) that may be used within the communication system illustrated in FIG. 1A. [Figure 1D] 1B is a system diagram of a further exemplary RAN and a further exemplary CN that may be used within the communication system illustrated in FIG. 1A. [Figure 2]This is an example associated with the resource pool layer. [Figure 3] 1 is an example associated with resource pool tier selection and usage. [Figure 4] 1 is an example associated with resource pool tier selection and usage. [Figure 5] 1 is an example associated with resource pool tier selection and usage. [Figure 6] 1 is an example associated with resource pool tier selection and usage. DETAILED DESCRIPTION OF THE INVENTION

[0006] A detailed description of exemplary embodiments will now be provided with reference to various figures. While this description provides detailed examples of possible implementations, it should be noted that these details are intended to be illustrative and in no way limit the scope of the present application.

[0007] 1A illustrates an exemplary communication system 100 in which one or more disclosed embodiments can be implemented. The communication system 100 may be a multiple-access system that provides content, such as voice, data, video, messaging, broadcast, etc., to multiple wireless users. The communication system 100 enables the multiple wireless users to access such content through the sharing of system resources, including wireless bandwidth. For example, the communication system 100 may employ one or more channel access methods, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single-carrier FDMA (SC-FDMA), zero-tailed unique word DFT-Spread OFDM (ZT UW DTS-s OFDM), unique word OFDM (UW-OFDM), resource block filtered OFDM, filter bank multicarrier (FBMC), etc.

[0008] 1A, communications system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, RANs 104 / 113, CNs 106 / 115, public switched telephone networks (PSTNs) 108, the Internet 110, and other networks 112, although it will be understood that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network elements. Each of WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and / or communicate in a wireless environment. For example, the WTRUs 102a, 102b, 102c, 102d (any of which may be referred to as a “station” and / or “STA”) may be configured to transmit and / or receive wireless signals and may include user equipment (UE), mobile stations, fixed or mobile subscriber units, subscription-based units, pagers, cellular phones, personal digital assistants (PDAs), smartphones, laptops, netbooks, personal computers, wireless sensors, hotspot or Mi-Fi devices, IoT devices, watches or other wearables, head-mounted displays (HMDs), vehicles, drones, medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in the context of industrial and / or automated processing chains), consumer electronics devices, devices operating on commercial and / or industrial wireless networks, etc. Any of the WTRUs 102a, 102b, 102c, and 102d may be interchangeably referred to as a UE.

[0009] The communications system 100 may include a base station 114a and / or a base station 114b. Each of the base stations 114a, 114b may be any type of device configured to wirelessly interface with at least one of the WTRUs 102a, 102b, 102c, 102d to facilitate access to one or more communications networks, e.g., the CN 106 / 115, the Internet 110, and / or other networks 112. For example, the base stations 114a, 114b may be a base transceiver station (BTS), a Node-B, an eNode-B, a home Node-B, a home eNode-B, a gNB, an NR Node-B, 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 understood that the base stations 114a, 114b may include any number of interconnected base stations and / or network elements.

[0010] The base station 114a may be part of the RAN 104 / 113, which may also include other base stations and / or network elements (not shown), e.g., a base station controller (BSC), a radio network controller (RNC), relay nodes, etc. The base station 114a and / or base station 114b may be configured to transmit and / or receive wireless signals on one or more carrier frequencies, which may be referred to as cells (not shown). These frequencies may be licensed spectrum, unlicensed spectrum, or a combination of licensed and unlicensed spectrum. A cell may provide coverage for wireless services to a particular geographic area, which may be relatively fixed or may change over time. A cell may be further divided into cell sectors. For example, the cell associated with the base station 114a may be divided into three sectors. Thus, in one embodiment, the base station 114a may include three transceivers, e.g., one transceiver for each sector of the cell. In an embodiment, the base station 114a may employ MIMO technology and utilize multiple transceivers for each sector of the cell. For example, beamforming may be used to transmit and / or receive signals in desired spatial directions.

[0011] The base stations 114a, 114b may communicate with one or more of the WTRUs 102a, 102b, 102c, 102d over the air interface 116, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet (UV), visible light, etc.). The air interface 116 may be established using any suitable radio access technology (RAT).

[0012] More specifically, as described above, the communication system 100 may be a multiple-access system and may employ one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, etc. For example, the base station 114a and the WTRUs 102a, 102b, 102c in the RAN 104 / 113 may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may establish the air interface 115 / 116 / 117 using wideband CDMA (WCDMA). WCDMA may include communication protocols such as High Speed ​​Packet Access (HSPA) and / or Evolved HSPA+ (HSPA+). HSPA may include High Speed ​​Downlink (DL) Packet Access (HSDPA) and / or High Speed ​​UL Packet Access (HSUPA).

[0013] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which may establish the air interface 116 using Long Term Evolution (LTE) and / or LTE Advanced (LTE-A) and / or LTE Advanced Pro (LTE-A Pro).

[0014] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as New Radio (NR) radio access, which may establish the air interface 116 using NR.

[0015] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement multiple radio access technologies. For example, the base station 114a and the WTRUs 102a, 102b, 102c may implement both LTE radio access and NR radio access, e.g., using a dual connectivity (DC) principle. Thus, the air interface utilized by the WTRUs 102a, 102b, 102c may be characterized by multiple types of radio access technologies and / or transmissions sent to / from multiple types of base stations (e.g., eNBs and gNBs).

[0016] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement a wireless technology such as IEEE 802.11 (e.g., Wireless Fidelity (WiFi)), IEEE 802.16 (e.g., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 1X, CDMA2000EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile Communications (GSM), Enhanced Data Rates for GSM Evolution (EDGE), GSM EDGE (GERAN), etc.

[0017] 1A may be, for example, a wireless router, a Home Node B, 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 business, a home, a vehicle, a campus, an industrial facility, an air corridor (e.g., for use by drones), a roadway, 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 picocell or femtocell. 1A, base station 114b may have a direct connection to the Internet 110. Thus, base station 114b may not be required to access the Internet 110 via CN 106 / 115.

[0018] The RAN 104 / 113 may be in communication with the CN 106 / 115, which may be any type of network configured to provide voice, data, application, and / or VoIP services to one or more of the WTRUs 102a, 102b, 102c, 102d. The data may have various quality of service (QoS) requirements, such as separate throughput, latency, error tolerance, reliability, data throughput, mobility, etc. The CN 106 / 115 may provide call control, billing services, mobile location services, prepaid calling, Internet connectivity, video distribution, etc., and / or perform high-level security functions, such as user authentication. Although not shown in FIG. 1A , it will be understood that the RAN 104 / 113 and / or the CN 106 / 115 may be in direct or indirect communication with other RANs employing the same RAT as the RAN 104 / 113 or a different RAT. For example, in addition to being connected to the RAN 104 / 113, which may utilize NR radio technology, the CN 106 / 115 may also be in communication with another RAN (not shown) employing GSM, UMTS, CDMA2000, WiMAX, E-UTRA, or WiFi radio technology.

[0019] The CN 106 / 115 may also serve as a gateway for the WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the Internet 110, and / or other networks 112. The PSTN 108 may include a circuit-switched telephone network providing Plain Old Telephone Service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices that use common communication protocols, such as TCP, UDP, and / or IP in the TCP / IP Internet protocol suite. The network 112 may include wired and / or wireless communication networks owned and / or operated by other service providers. For example, the network 112 may include another CN connected to one or more RANs, which may employ the same RAT as the RAN 104 / 113 or a different RAT.

[0020] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communications system 100 may include multi-mode capabilities (e.g., the WTRUs 102a, 102b, 102c, 102d may include multiple transceivers for communicating with separate wireless networks over separate wireless links.) For example, the WTRU 102c shown in FIG. 1A may be configured to communicate with a base station 114a that may employ a cellular-based wireless technology and with a base station 114b that may employ an IEEE 802.11 wireless technology.

[0021] 1B is a system diagram illustrating an example WTRU 102. As shown in FIG. 1B, the WTRU 102 may include, among other things, a processor 118, a transceiver 120, a transmit / receive element 122, a speaker / microphone 124, a keypad 126, a display / touchpad 128, non-removable memory 130, removable memory 132, a power source 134, a GPS chipset 136, and / or other peripherals 138. It will be understood that the WTRU 102 may include any sub-combination of the above elements while remaining consistent with an embodiment.

[0022] The processor 118 may be a general-purpose processor, a special-purpose processor, a conventional processor, a digital signal processor (DSP), multiple microprocessors, one or more microprocessors associated with a DSP core, a controller, a microcontroller, an application specific integrated circuit (ASIC), an FPGA circuit, any other type of integrated circuit (IC), a state machine, etc. The processor 118 may perform signal coding, data processing, power control, input / output processing, and / or any other functionality that enables the WTRU 102 to operate in a wireless environment. The processor 118 may be coupled to the transceiver 120, which may be coupled to the transmit / receive element 122. While FIG. 1B depicts the processor 118 and the transceiver 120 as separate components, it will be understood that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip.

[0023] The transmit / receive element 122 may be configured to transmit signals to or receive signals from a base station (e.g., the base station 114a) over the air interface 116. For example, in one embodiment, the transmit / receive element 122 may be an antenna configured to transmit and / or receive RF signals. In an embodiment, the transmit / receive element 122 may be an emitter / detector configured to transmit and / or receive, for example, IR signals, UV signals, or visible light signals. In yet another embodiment, the transmit / receive element 122 may be configured to transmit and / or receive both RF signals and light signals. It will be understood that the transmit / receive element 122 may be configured to transmit and / or receive any combination of wireless signals.

[0024] 1B as a single element, the WTRU 102 may include any number of transmit / receive elements 122. More specifically, the WTRU 102 may employ MIMO technology. Thus, in one embodiment, the WTRU 102 may include two or more transmit / receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals over the air interface 116.

[0025] The transceiver 120 may be configured to modulate signals to be transmitted by the transmit / receive element 122 and to demodulate signals received by the transmit / receive element 122. As mentioned above, the WTRU 102 may have multi-mode capabilities. Thus, the transceiver 120 may include multiple transceivers to enable the WTRU 102 to communicate via multiple RATs, such as NR and IEEE 802.11.

[0026] The processor 118 of the WTRU 102 may be coupled to and may receive user input data from the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128 (e.g., a liquid crystal display (LCD) display unit or an organic light emitting diode (OLED) display unit). The processor 118 may also output user data to the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128. Additionally, the processor 118 may access information and store data in any type of suitable memory, e.g., non-removable memory 130 and / or removable memory 132. The non-removable memory 130 may include RAM, ROM, a hard disk, or any other type of memory storage device. The removable memory 132 may include a SIM card, a memory stick, an SD memory card, etc. In other embodiments, the processor 118 may access information and store data in memory not physically located on the WTRU 102, e.g., on a server or home computer (not shown).

[0027] The processor 118 may receive power from the power source 134 and may be configured to distribute and / or control power to other components in the WTRU 102. The power source 134 may be any suitable device for powering the WTRU 102. For example, the power source 134 may include one or more dry batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel-metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, etc.

[0028] The processor 118 may also be coupled to a GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) regarding the current location of the WTRU 102. The WTRU 102 may receive location information over the air interface 116 from a base station (e.g., base stations 114a, 114b) in addition to or instead of information from the GPS chipset 136 and / or determine its location based on the timing of signals received from two or more neighboring base stations. It will be appreciated that the WTRU 102 may obtain location information through any suitable location determination method while remaining consistent with an embodiment.

[0029] The processor 118 may further be coupled to other peripherals 138, which may include one or more software and / or hardware modules that provide additional features, functionality, and / or wired or wireless connectivity. For example, the peripherals 138 may include an accelerometer, an e-compass, a satellite transceiver, a digital camera (for photos and / or videos), a USB port, a vibration device, a television transceiver, a hands-free headset, a Bluetooth module, a frequency modulation (FM) radio unit, a digital music player, a media player, a video game player module, an internet browser, a virtual reality and / or augmented reality (VR / AR) device, an activity tracker, etc. The 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 geolocation sensor, an altimeter, a light sensor, a touch sensor, a magnetometer, a barometer, a gesture sensor, a biometric sensor, and / or a humidity sensor.

[0030] The WTRU 102 may include a full-duplex radio in which the transmission and reception of some or all of the signals (e.g., associated with a particular subframe for both the UL (e.g., for transmission) and DL (e.g., for reception)) may be parallel and / or simultaneous. The full-duplex radio may include an interference management unit 139 to reduce and or substantially eliminate self-interference through signal processing in hardware (e.g., a choke) or via a processor (e.g., via a separate processor (not shown) or via processor 118). In an embodiment, the WTRU 102 may include a half-duplex radio for the transmission and reception of some or all of the signals (e.g., associated with a particular subframe for either the uplink (e.g., for transmission) or downlink (e.g., for reception)).

[0031] 1C is a system diagram illustrating the RAN 104 and the 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 over the air interface 116. The RAN 104 may also be in communication with the CN 106.

[0032] The RAN 104 may include eNode-Bs 160a, 160b, and 160c, although it will be understood that the RAN 104 may include any number of eNode-Bs while remaining consistent with an embodiment. The eNode-Bs 160a, 160b, and 160c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, and 102c over the air interface 116. In one embodiment, the eNode-Bs 160a, 160b, and 160c may implement MIMO techniques. Thus, the eNode-B 160a may use multiple antennas, for example, to transmit wireless signals to and / or receive wireless signals from the WTRU 102a.

[0033] Each of the eNode-Bs 160a, 160b, 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the UL and / or DL, etc. As shown in FIG. 1C, the eNode-Bs 160a, 160b, 160c may communicate with each other via an X2 interface.

[0034] 1C may include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (or PGW) 166. Although each of the above elements is depicted as part of the CN 106, it will be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0035] The MME 162 may be connected to each of the eNode-Bs 162a, 162b, 162c in the RAN 104 via an S1 interface and may act as a control node. For example, the MME 162 may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, activating / deactivating bearers, selecting a particular serving gateway during initial connection of the WTRUs 102a, 102b, 102c, etc. The MME 162 may provide a control plane function for switching between the RAN 104 and other RANs (not shown) employing other radio technologies such as GSM and / or WCDMA.

[0036] The SGW 164 may be connected to each of the eNode Bs 160a, 160b, 160c in the RAN 104 via an S1 interface. The SGW 164 may generally route and forward user data packets to / from the WTRUs 102a, 102b, 102c. The SGW 164 may perform other functions, such as fixing the user plane during handover between eNode Bs, triggering paging when DL data is available for the WTRUs 102a, 102b, 102c, managing and storing the context of the WTRUs 102a, 102b, 102c, etc.

[0037] The SGW 164 may be connected to a PGW 166, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communication between the WTRUs 102a, 102b, 102c and IP-enabled devices.

[0038] The CN 106 may facilitate communication with other networks. For example, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to circuit-switched networks, such as the PSTN 108, to facilitate communication between the WTRUs 102a, 102b, 102c and traditional landline communication devices. For example, the CN 106 may include or communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that serves as an interface between the CN 106 and the PSTN 108. Additionally, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers.

[0039] Although the WTRU is depicted in FIGS. 1A-1D as a wireless terminal, in certain representative embodiments it is contemplated that such a terminal may be capable of using a wired communication interface (e.g., temporarily or permanently) with the communication network.

[0040] In an exemplary embodiment, the other network 112 may be a WLAN.

[0041] A WLAN in infrastructure basic service set (BSS) mode may have an access point (AP) for the BSS and one or more stations (STAs) associated with the AP. The AP may have access to or interface with a distribution system (DS) or another type of wired / wireless network that carries traffic to and from the BSS. Traffic to a STA originating from outside the BSS may arrive through the AP and be delivered to the STA. Traffic originating from a STA to a destination outside the BSS may be sent to the AP for delivery to the respective destination. Traffic between STAs within a BSS may be sent through the AP, for example, if the source STA can send traffic to the AP, which can deliver the traffic to the destination STA. Traffic between STAs within a BSS may be considered and / or referred to as peer-to-peer traffic. Peer-to-peer traffic may be sent (e.g., directly) between a source STA and a destination STA using direct link setup (DLS). In certain representative embodiments, the DLS may use 802.11e DLS or 802.11z Tunneled DLS (TDLS). A WLAN using an Independent BSS (IBSS) mode may have no APs, and STAs within or using an IBSS (e.g., all of the STAs) may communicate directly with each other. The IBSS mode of communication may sometimes be referred to herein as an "ad hoc" mode of communication.

[0042] When using the 802.11ac infrastructure mode of operation or a similar mode of operation, an AP may transmit beacons on a fixed channel, such as a primary channel. The primary channel may be of a fixed width (e.g., a 20 MHz wide bandwidth) or dynamically configured via signaling. The primary channel may be the operating channel of the BSS and may be used by STAs to establish a connection with the AP. In certain representative embodiments, for example, in an 802.11 system, Carrier Sense Multiple Access with Collision Avoidance (CSMA / CA) may be implemented. With CSMA / CA, STAs (e.g., all STAs), including the AP, may sense the primary channel. If the primary channel is sensed / detected by a particular STA and / or determined to be busy, the particular STA may back out. One STA (e.g., only one station) may transmit in a given BSS at any given time.

[0043] High-throughput (HT) STAs may, for example, use 40 MHz wide channels for communication via a combination of a primary 20 MHz channel and adjacent or non-adjacent 20 MHz channels to form a 40 MHz wide channel.

[0044] A Very High Throughput (VHT) STA may support channels of 20 MHz, 40 MHz, 80 MHz, and / or 160 MHz width. A 40 MHz channel and / or an 80 MHz channel may be formed by combining adjacent 20 MHz channels. A 160 MHz channel may be formed by combining eight adjacent 20 MHz channels or two non-adjacent 80 MHz channels (which may be referred to as an 80+80 configuration). For the 80+80 configuration, after channel encoding, the data may be passed through a segment parser, which may split the data into two streams. Inverse Fast Fourier Transform (IFFT) processing and time-domain processing may be performed separately on each stream. The streams may be mapped onto two 80 MHz channels, and the data may be transmitted by the transmitting STA. At the receiver of the receiving STA, the operations described above for the 80+80 configuration can be reversed and the combined data can be sent to the Medium Access Control (MAC).

[0045] Sub-1 GHz modes of operation are supported by 802.11af and 802.11ah. Channel operating bandwidths and carriers are reduced in 802.11af and 802.11ah compared to those used in 802.11n and 802.11ac. 802.11af supports 5 MHz, 10 MHz, and 20 MHz bandwidths in the TV White Space (TVWS) spectrum, while 802.11ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths using non-TVWS spectrum. According to representative embodiments, 802.11ah can support meter-type control / machine-type communications, such as MTC devices in macro coverage areas. MTC devices can have limited capabilities, including support for (e.g., only support for) specific and / or limited bandwidths. MTC devices can include batteries with above-threshold battery life (e.g., to maintain very long battery life).

[0046] A WLAN system capable of supporting multiple channels and channel bandwidths, e.g., 802.11n, 802.11ac, 802.11af, and 802.11ah, includes a channel that may be designated as a primary channel. The primary channel may have a bandwidth equal to the largest common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel may be set and / or limited by the STA supporting the smallest bandwidth operating mode among all STAs operating in the BSS. In the example of 802.11ah, for a STA (e.g., an MTC-type device) that supports (e.g., only supports) the 1 MHz mode, the primary channel may 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 operating modes. Carrier sensing and / or network allocation vector (NAV) setting may depend on the status of the primary channel. If the primary channel is busy, for example due to STAs (that only support a 1 MHz mode of operation) transmitting to the AP, then the entire available frequency band may be considered busy, even though most of those frequency bands may remain idle and available.

[0047] In the United States, the available frequency band that can be used by 802.11ah is from 902 MHz to 928 MHz. In South Korea, the available frequency band is from 917.5 MHz to 923.5 MHz. In Japan, the available frequency band is from 916.5 MHz to 927.5 MHz. The total available bandwidth for 802.11ah is from 6 MHz to 26 MHz depending on the country code.

[0048] 1D is a system diagram illustrating the RAN 113 and the CN 115 according to an embodiment. As described above, the RAN 113 may employ NR radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 113 may also be in communication with the CN 115.

[0049] The RAN 113 may include gNBs 180a, 180b, and 180c, although it will be understood that the RAN 113 may include any number of gNBs while remaining consistent with an embodiment. The gNBs 180a, 180b, and 180c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, and 102c over the air interface 116. In one embodiment, the gNBs 180a, 180b, and 180c may implement MIMO techniques. For example, the gNBs 180a and 180b may utilize beamforming to transmit signals to and / or receive signals from the gNBs 180a, 180b, and 180c. Thus, the gNB 180a may use multiple antennas to transmit wireless signals to and / or receive wireless signals from the WTRU 102a, for example. In an embodiment, the gNBs 180a, 180b, and 180c may implement carrier aggregation techniques. For example, the gNB 180a may transmit multiple component carriers to the WTRU 102a (not shown). A subset of these component carriers may be on an unlicensed spectrum, while the remaining component carriers may be on a licensed spectrum. In an embodiment, the gNBs 180a, 180b, and 180c may implement coordinated multipoint (CoMP) techniques. For example, the WTRU 102a may receive coordinated transmissions from the gNBs 180a and 180b (and / or 180c).

[0050] The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using transmissions associated with scalable numerology. For example, the OFDM symbol spacing and / or OFDM subcarrier spacing may be different for different transmissions, different cells, and / or different portions of the wireless transmission spectrum. The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using subframes or transmission time intervals (TTIs) of varying or scalable lengths (e.g., including different numbers of OFDM symbols and / or different lengths of absolute time duration).

[0051] The gNBs 180a, 180b, 180c may be configured to communicate with the WTRUs 102a, 102b, 102c in a standalone configuration and / or a non-standalone configuration. In a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c without accessing other RANs (e.g., eNode-Bs 160a, 160b, 160c, etc.). In a standalone configuration, the WTRUs 102a, 102b, 102c may utilize one or more of the gNBs 180a, 180b, 180c as mobility anchor points. In a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using signals in unlicensed bands. In a non-standalone configuration, the WTRUs 102a, 102b, 102c may communicate / connect to a gNB 180a, 180b, 180c while also communicating / connecting to another RAN, such as an eNode-B 160a, 160b, 160c. For example, the WTRUs 102a, 102b, 102c may implement the DC principle to communicate with one or more gNBs 180a, 180b, 180c and one or more eNode-Bs 160a, 160b, 160c substantially simultaneously. In a non-standalone configuration, the eNode-Bs 160a, 160b, 160c may act as mobility anchors for the WTRUs 102a, 102b, 102c, and the gNBs 180a, 180b, 180c may provide additional coverage and / or throughput for serving the WTRUs 102a, 102b, 102c.

[0052] Each of the gNBs 180a, 180b, 180c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the UL and / or DL, support for network slicing, dual connectivity, interworking between NR and E-UTRA, routing of user plane data to user plane functions (UPFs) 184a, 184b, routing of control plane information to access and mobility management functions (AMFs) 182a, 182b, etc. As shown in FIG. 1D , the gNBs 180a, 180b, 180c may communicate with each other via an Xn interface.

[0053] 1D may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one Session Management Function (SMF) 183a, 183b, and possibly a Data Network (DN) 185a, 185b. While each of the above elements is shown as part of the CN 115, it will be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0054] The AMF 182a, 182b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via an N2 interface and may act as a control node. For example, the AMF 182a, 182b may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, supporting network slicing (e.g., handling separate PDU sessions with separate requirements), selecting a particular SMF 183a, 183b, managing registration areas, terminating NAS signaling, mobility management, etc. Network slicing may be used by the AMF 182a, 182b to customize CN support for the WTRUs 102a, 102b, 102c based on the type of service being utilized by the WTRUs 102a, 102b, 102c. For example, separate network slices may be established for separate use cases, such as services relying on Ultra-Reliable Low-Latency (URLLC) access, services relying on enhanced High-Capacity Mobile Broadband (eMBB) access, services related to Machine-Type Communications (MTC) access, etc. The AMF 162 may provide a control plane function for switching between the RAN 113 and other RANs (not shown) employing other radio technologies such as LTE, LTE-A, LTE-A Pro, and / or non-3GPP access technologies such as WiFi.

[0055] The SMFs 183a and 183b may be connected to the AMFs 182a and 182b in the CN 115 via an N11 interface. The SMFs 183a and 183b may also be connected to the UPFs 184a and 184b in the CN 115 via an N4 interface. The SMFs 183a and 183b may select and control the UPFs 184a and 184b and configure the routing of traffic through the UPFs 184a and 184b. The SMFs 183a and 183b may perform other functions, such as managing and assigning UE IP addresses, managing PDU sessions, controlling policy enforcement and QoS, providing downlink data notification, etc. The PDU session type may be IP-based, non-IP-based, Ethernet-based, etc.

[0056] The UPFs 184a, 184b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via an N3 interface, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communication between the WTRUs 102a, 102b, 102c and IP-enabled devices. The UPFs 184, 184b may perform other functions, such as routing and forwarding packets, enforcing user plane policies, supporting multi-homed PDU sessions, handling user plane QoS, buffering downlink packets, providing mobility anchoring, etc.

[0057] The CN 115 may facilitate communication with other networks. For example, the CN 115 may include or communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that acts as an interface between the CN 115 and the PSTN 108. In addition, the CN 115 may provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers. In one embodiment, the WTRUs 102a, 102b, 102c may be connected to the local data networks (DNs) 185a, 185b through the UPFs 184a, 184b via an N3 interface to the UPFs 184a, 184b and an N6 interface between the UPFs 184a, 184b and the DNs 185a, 185b.

[0058] 1A-1D and the corresponding descriptions thereof, one or more or all of the functions described herein in connection with one or more of the WTRUs 102a-d, base stations 114a-b, eNode-Bs 160a-c, MME 162, SGW 164, PGW 166, gNBs 180a-c, AMFs 182a-b, UPFs 184a-b, SMFs 183a-b, DNs 185a-b, and / or any other devices described herein may be performed by one or more emulation devices (not shown). The emulation devices may be one or more devices configured to emulate one or more or all of the functions described herein. For example, the emulation devices may be used to test other devices and / or to simulate network and / or WTRU functionality.

[0059] The emulation device may be designed to perform one or more tests of other devices in a lab environment and / or in an operator network environment. For example, one or more emulation devices may perform one or more or all functions while fully or partially implemented and / or deployed as part of a wired and / or wireless communication network to test other devices in that network. One or more emulation devices may perform one or more or all functions while temporarily implemented / deployed as part of a wired and / or wireless communication network. The emulation device may be directly coupled to another device for testing purposes and / or may perform testing using over-the-air wireless communication.

[0060] The one or more emulation devices may perform one or more functions, including all functions, while not implemented / deployed as part of a wired and / or wireless communication network. For example, the emulation devices may be utilized in a testing laboratory and / or testing scenario in an undeployed (e.g., testing) wired and / or wireless communication network to perform testing of one or more components. The one or more emulation devices may be test equipment. Direct RF coupling and / or wireless communication via RF circuitry (which may, for example, include one or more antennas) may be used by the emulation devices to transmit and / or receive data.

[0061] Wireless communications can support applications with a variety of requirements. For example, some applications may be low latency, while others may be delay tolerant. Some applications may be high reliability, while others may be less critical. Applications may include, for example, enhanced mobile broadband (eMBB), machine type communications (MTC), massive MTC (mMTC), and ultra-reliable low latency communications (URLLC). Applications may be useful in a wide range of industries, such as the automotive, health, agricultural, utility, and logistics industries.

[0062] Wireless communications may be deployed using licensed and / or unlicensed spectrum. The unlicensed spectrum may be used, for example, for non-cellular services and applications such as Wi-Fi and / or cellular services (e.g., broadband data services). The unlicensed spectrum may be shared by multiple users who may interfere with each other, which may impose constraints on the use of the unlicensed spectrum.

[0063] The operation or use of a cell, transmit reception point (TRP), or carrier in an unlicensed band can be, for example, standalone or assisted by the operation or use of a cell, TRP, or carrier in a licensed band. An assisted deployment scenario can be referred to as licensed assisted access (LAA). A licensed cell, TRP, or carrier can be a primary or anchor cell, TRP, or carrier.

[0064] For example, to minimize interference and provide fairness between spectrum users, coexistence between cellular systems operating with unlicensed technologies (e.g., Wi-Fi) and cellular operators in unlicensed spectrum may be considered. Mechanisms such as Listen Before Talk (LBT) or Clear Channel Assessment (CCA) may be used (e.g., for fair coexistence). In an example, a system node such as an access point (AP), eNodeB (eNB), gNodeB (gNB), TRP, user equipment (WTRU), etc. may listen to a channel (e.g., a frequency band having a particular center frequency and bandwidth) to determine, for example, whether another user is likely using the channel before transmitting on the channel or a portion thereof. Listening and / or determining use by another user may include or be based on, for example, measurements (e.g., energy sensing).

[0065] LBT, CCA, and LBT / CCA may be used interchangeably herein. A channel may be determined to be busy, occupied, or in use, for example, if a measurement (e.g., of energy) may be greater than or equal to a threshold. A channel may be determined to be idle, free, clear, or not in use, for example, if a measurement (e.g., of energy) may be less than or equal to a threshold.

[0066] "Clear," "free," "idle," "unoccupied," and "not busy" can be used interchangeably. "Not clear," "not free," "not idle," "occupied," and "busy" can be used interchangeably. Channel and operating channel can be used interchangeably. A CCA fail can mean, for example, that the channel may be busy (e.g., is busy). A CCA pass can mean, for example, that the channel may be clear.

[0067] A potential transmitter on a channel (e.g., a WTRU with a potential UL transmission and / or an eNB with a potential DL transmission) may evaluate and / or monitor (e.g., receive) the channel prior to transmission (e.g., to measure and / or determine signal presence or interference on the channel) to determine, for example, whether the channel may be in use (e.g., busy and / or occupied) by another, such as another system, user, or signal.

[0068] A potential transmitter may compare a received signal and / or interference from a channel to a criterion (e.g., one or more threshold levels) (e.g., as part of LBT / CCA) to determine (e.g., based on the comparison), for example, whether the channel is likely to be free. A potential transmitter may transmit on a channel, for example, if the potential transmitter determines that the channel is likely to be free. A potential transmitter may not transmit on a channel, postpone a potential transmission, and / or abandon a potential transmission, for example, if the potential transmitter determines that the channel is not likely to be free.

[0069] A frame-based equipment (FBE) may refer to equipment whose transmit / receive timing may be fixed and / or structured. A load-based equipment (LBE) may not perform LBT / CCA according to a particular frame structure, for example, at a fixed or defined time. An LBE may perform LBT / CCA, for example, when the LBE has data to transmit.

[0070] An equipment may refer to a node or device (e.g., a WTRU, eNB, gNB, TRP, STA, or AP) that is capable of transmitting and / or receiving on licensed and / or unlicensed channels.

[0071] An eNB may be used to refer to or represent one or more of a gNB, a TRP, a STA, a cell, and / or an AP, where eNB, gNB, TRP, STA, cell, and AP may be used interchangeably.

[0072] In an example, a device may perform an LBT / CCA check (eg, to detect energy on the channel), for example, before a transmission or burst of transmissions on an operating channel.

[0073] The LBT / CCA time period for channel estimation may be a fixed time and / or may have a minimum time.

[0074] Channel Occupancy Time (COT) may be the total time that a device may have transmission on a given channel, for example, without re-evaluating the availability of that channel.

[0075] Maximum COT (MCOT) may be the total time a device may utilize an operating channel for a given transmission or burst of transmissions.

[0076] The value of MCOT can be configured or permitted (e.g., by regulation). MCOT can be, for example, 4 ms or 10 ms.

[0077] The MCOT for a device may be less than a maximum allowable value, which may be set, for example, by the device manufacturer.

[0078] An idle period may be a time (eg, a contiguous period of time) during which a device may not transmit on a channel.

[0079] The idle period may have a minimum value (eg, for COT, 5% of COT, etc.) that may be used by the device, for example, during the current fixed frame period.

[0080] For example, if a device finds that one or more operating channels are clear (e.g., during or as a result of LBT / CCA), the device may transmit (e.g., immediately) on one or more clear channels.

[0081] For example, if a device finds that an operating channel is occupied (e.g., during or as a result of an LBT / CCA), the device may not transmit on the channel. The device may perform a subsequent LBT / CCA, which may find the channel clear.

[0082] For example, if a device finds that the operating channel is occupied (e.g., during or as a result of LBT / CCA), the device may not transmit on the channel (e.g., during the next fixed frame period).

[0083] An LBT / CCA performed after an LBT / CCA in which the channel is found not to be clear may include, for example, a waiting or backoff time before checking whether the channel is clear.

[0084] An LBT / CCA that may be performed after an LBT / CCA in which the channel may not be found to be clear may, for example, include a longer period to determine whether the channel may be clear and then transmit.

[0085] The WTRU may perform CCA to determine, for example, whether the channel is likely to be free. The WTRU may add an additional backoff or waiting time, such as an additional contention window amount of time, if the WTRU determines that the channel is not free. The WTRU may check again (e.g., upon determining that the channel is free) before the actual transmission, for example, in case the actual transmission cannot start immediately after the channel can be determined to be free.

[0086] In an example, the WTRU may perform CCA (e.g., for at least a check window amount of time before the actual transmission) if, for example, the WTRU may not be within a check window (e.g., 25 μs) before the actual transmission. The WTRU may transmit (e.g., only transmit) if, for example, the channel may be determined to be free (e.g., for at least a portion of the check window amount of time).

[0087] CCA can be, for example, a full CCA or a short CCA. Full CCA can include, for example, adding one or more back-off times if, for example, the channel can be determined to be busy. Short CCA can be, for example, a quick check (e.g., an energy detection check) in a check window before the start of a transmission or an intended or planned transmission.

[0088] The WTRU may perform a full CCA (e.g., to determine if the channel is likely to be free), e.g., when the WTRU is able to perform CCA on the first subframe (SF) or symbol. The WTRU may perform a short CCA (e.g., to recheck that the channel is still free), e.g., before transmission, e.g., when there may be a gap between the end of the full CCA and the beginning of the transmission.

[0089] Access to, use of resources on, or transmission on a channel, in, to, a TRP or another node can be, for example, grant-based, allocation-based, or scheduler-based.

[0090] In an example, the WTRU may transmit (e.g., only transmit) on a set of resources in response to or in accordance with a received grant or allocation of resources. The resources may be, for example, time resources and / or frequency resources.

[0091] The grant or allocation may be provided (e.g., explicitly), for example, in DL control information (DCI), or may be configured (e.g., by higher layer signaling) and may be used by the WTRU, for example, when the WTRU has data to transmit.

[0092] Access to, use of, or transmission on a channel, in, to, a TRP or other node, resource, or resource can be grant-less or grant-free. Grant-less and grant-free can be used interchangeably. Resources can be, for example, time resources and / or frequency resources.

[0093] A WTRU may transmit on a set of resources, e.g., if the WTRU may have a transmission to make. The WTRU may determine or select the resources on which it may transmit, e.g., from one or more configured sets of resources. The set of resources may be configured by the eNB.

[0094] A resource may be shared and / or used by multiple WTRUs. The resource may be referred to as a contention-based resource. For example, if the WTRUs are able to select and / or transmit on the same resource at the same time, the transmissions of the multiple WTRUs may collide.

[0095] Mechanisms for reducing the likelihood of collisions may be included. In an example, resource selection may be determined randomly (e.g., wholly or partially). Resource selection may be a function of WTRU-ID. Different groups of WTRUs may be configured with different sets of resources.

[0096] The mechanism allows a receiver of a grant-free transmission to identify the sender. In an example, the transmission may include an identifier or a partial identifier.

[0097] The WTRU may perform CCA (e.g., in an LTE LAA UL scenario) for transmissions that start on a boundary at the beginning of a time period or on a boundary of a time unit, which may be within a time period.

[0098] Examples of a time period may include, for example, a subframe (SF), a frame, a slot, a minislot, a set of slots or minislots, a TTI, a short TTI, a multi-symbol TTI, a symbol, a set of TTIs, a set of symbols, a synchronization burst, a synchronization block, a set of synchronization bursts or blocks, etc. A time period may include one or more time units. Examples of a time unit may include, for example, a symbol, a slot, a minislot, a TTI, a short TTI, a multi-symbol TTI, a set of symbols, a synchronization burst, a synchronization block, etc. For example, the WTRU may perform CCA on a channel during one or more of the time units included in the time period until it determines that the channel is free (e.g., it may perform CCA periodically).

[0099] In an example, a WTRU may perform CCA, for example, on a transmission starting on a subframe (SF) boundary or on an indicated symbol boundary within an SF. The WTRU may receive a grant, for example, for an SF (e.g., a complete SF or a partial SF) or a set of consecutive subframes. The WTRU may perform CCA, for example, before transmission on an allowed SF. If the WTRU is able to determine, for example, that CCA is unsuccessful (e.g., the channel may not be busy or idle) (e.g., for a set of SFs that may be allowed), the WTRU may perform CCA on the next (or subsequent) allowed SF. If the WTRU is able to determine, for example, that the channel is free for an SF in the allowed SF set, the WTRU may transmit on the SFs in the allowed set and the remaining SFs. For example, if transmissions may be continuous, transmissions may be performed without performing CCA on subsequent SFs. If there may be an interruption in transmission, the WTRU may perform CCA on transmissions on SFs in the set after the interruption.

[0100] A WTRU that performs CCA for transmissions on specific time period boundaries, such as SFs or specific symbol boundaries, may be at a disadvantage in accessing the channel relative to another device (e.g., a WiFi device) that may not be constrained to specific boundaries for CCA or transmissions.

[0101] A WTRU that is able to transmit based on receiving a grant, schedule, or allocation of resources may be at a disadvantage in accessing the channel relative to another device (e.g., a WiFi device) that may not be constrained to waiting for a grant, schedule, or allocation.

[0102] For example, systems, methods, and means are disclosed for transmission adaptation and / or grant-free access in unlicensed bands. Flexible transmission boundaries can be provided for transmission adaptation. Grant-free access resource pools can be provided. Unlicensed operation can be provided in beam-based systems, for example, using resource pools and / or CCA.

[0103] Flexible transmission boundaries may be provided, for example, for transmission adaptation. CCA and transmission may not be limited to a time period (e.g., a subframe) or time unit. For example, if CCA may fail for a time unit (e.g., a symbol) within a time period (e.g., a subframe), the CCA may be repeated (e.g., at the next or other time unit).

[0104] Frequency resource adaptation may be provided.

[0105] The frequency resources may be adapted, for example, based on the time remaining in the time period for transmission. A set of frequency resources may be selected from a configured candidate set. For example, if there is little time (e.g., one or more time units) remaining in the time period, the WTRU may select a resource for transmission that includes more frequency resources.

[0106] The MIMO scheme may be adapted, for example, based on the frequency resource set used. MIMO as described herein may refer to MIMO or massive MIMO.

[0107] The DM-RS may be used to indicate the frequency resource set to be used. The use of slots and minislots may be based on the available time for transmission and adapt the position of the DM-RS, e.g., based on the slot, minislot, and / or start time. The DM-RS may be placed at the end time of the transmission (e.g., in the last one or two symbols). A sequence may identify the resource set to be used. For example, a sequence that may be used to identify the resource set may be signaled to the WTRU (e.g., signaled by the eNB).

[0108] The numerology (subcarrier spacing) can be adapted, for example, based on the time remaining in the time period for transmission.

[0109] In instances where the maximum power is exceeded, e.g., the frequency may be limited or adjusted, there may be a shift to the next or other subsequent time period where the entire amount of time may be available for transmission. For example, the TBS may be adjusted and / or a modulation order may be selected (e.g., from a candidate set) to avoid exceeding the maximum power. The DM-RS may indicate which TBS and / or modulation order to use.

[0110] The beam sweeping operation (e.g., the number of beams to sweep) can be adapted based on, for example, the subcarrier spacing / symbol duration and / or the time remaining within the time period for transmission.

[0111] Data size adaptation may be provided. The amount of data to transmit may be adapted, for example, based on the available time for transmission. In an example, the TBS may be adapted, code block segmentation may be used, and / or the number of code blocks transmitted may be changed, for example, based on the available time for transmission. For example, multiple minislots may be used to allow for the transmission of segmented transport blocks.

[0112] For example, for delayed control channels and / or short PUCCHs, control channel adaptation can be provided. In examples (e.g., for delayed control channels), content can be modified, for example, to include A / Ns for more DL transmissions. In examples (e.g., for short PUCCHs), coverage can be improved by repetition in time or frequency, and / or CQI can be dropped (e.g., if it would not fit). The PUCCH type (e.g., DM-RS-based or sequence-based) can be determined, for example, based on the time available for transmission.

[0113] An adaptation of the transmission times can be provided.

[0114] In an example of a start configuration, a WTRU may be configured with a set of start times or start points. The WTRU may perform CCA with respect to a first start point. The WTRU may try the next or subsequent start point, for example, if the first start point fails CCA.

[0115] In the example of a short transmission time, the time available for transmission can be a function of when the transmission begins, eg, when the end can be fixed or configurable.

[0116] In a fixed or configured transmission time example, the transmission time may be based on when the WTRU starts transmitting. The WTRU may transmit B full TBs, where B may be, for example, the number of full TBs that can fit into the available time in the assigned or allowed time period for when the WTRU starts transmitting. In (e.g., alternative) examples, the first or last TB may be short, for example, based on when the WTRU starts, while the other TBs may be full size.

[0117] An indication of a start time and an end time may be provided. In an example, the WTRU may transmit a reference signal (RS) or a control channel, for example, to indicate the beginning and / or end of a transmission. The RS or control channel may use frequency resources, which may be the same, regardless of the subset of frequency resources that may be used. In an example (e.g., an alternative example), the RS location may depend on the subset of frequency resources that may be used.

[0118] CCA frequency adaptation may be provided. In an example, CCA may be performed for a band (e.g., a maximum band) or a set of frequencies, which may include all candidate sets of frequencies that may be used by the WTRU. CCA may be performed on multiple subbands, for example, to enable selection of a compatible subband set. The WTRU may, for example, puncture out (e.g., not use / measure) one or more subbands when performing CCA (e.g., to enable use of the subbands by other WTRUs).

[0119] The CCA capabilities of the WTRU may be provided. The WTRU may have or report capabilities regarding the time granularity at which the WTRU is able to perform continuous CCA, which may be a function of, for example, the subcarrier spacing used.

[0120] A grant-free access resource pool may be provided.

[0121] A resource pool can be configured, for example, with a schedule or pattern in time and / or frequency, and with a recurrence (e.g., periodicity). The pool can include a candidate set of frequencies. Time resources can be relative to a reference point (e.g., a synchronization burst or block), which can be beam-specific.

[0122] Pool allocation and WTRU identification may be provided. WTRUs and resource pools may be allocated to groups. WTRUs may receive a grant free mask or RNTI, for example, to scramble the CRC of their transmissions.

[0123] A resource pool tier may be provided. A WTRU may be configured with a resource pool tier with different resource availability (e.g., different recurrences). For example, if the WTRU is unable to transmit using resources in a first tier (e.g., due to the channel being busy N times), the WTRU may transmit using resources in a second tier (with more frequent resources). Resource pools may have and / or be used for transmissions of different types or with different priorities (e.g., URLLC vs. eMBB, transmission vs. retransmission).

[0124] A switch to grant-based transmission can be made. The request for the switch can be made, for example, by SR or PRACH on a licensed or unlicensed channel. The request can be made, for example, after a threshold number of times (e.g., for one or more layers) of being unable to obtain a channel.

[0125] Unlicensed operation can be provided in beam-based systems, for example, using resource pools and / or performing CCA.

[0126] A resource pool may be provided in a beam-based system. In an example, the resource pool may be associated with a beam or BPL. The resource pool may be configured, for example, based on a DL signal (e.g., a beam discovery signal or RS) for measuring quality. The resource pool may be within the same time resource as the synchronization burst or synchronization block of the associated beam. For example, if a threshold number (e.g., N) of grant-free access attempts fail (e.g., CCA may fail or ACK may not be received), another pool associated with another beam may be tried.

[0127] CCA may be performed in a beam-based system. In an example, the receive beam for CCA for a resource pool associated with a beam may be, for example, a receive beam that may be used for beam determination, a beam with the highest RSRP, or a receive beam that may be associated with a transmit beam. The WTRU may perform CCA on one or more (e.g., all) receive beams. The WTRU may use the highest detected energy or the average detected energy. The WTRU may perform CCA again (e.g., before transmitting) on ​​a receive beam that may correspond to a transmit beam.

[0128] Flexible transmission boundaries may be provided and / or used.

[0129] The WTRU may perform CCA on a transmission at the beginning of a time unit that may be within a time period (e.g., it may perform CCA periodically). In an example, the WTRU may try again (e.g., if the CCA fails) at a subsequent time, e.g., a subsequent time associated with a time unit that may be within a time period. The WTRU may continue to perform CCA on time units included within a time period until it determines that the channel is free (e.g., when the CCA passes). The WTRU may transmit starting at a subsequent time unit (e.g., if the CCA passes).

[0130] The WTRU transmission may end, for example, before or at the end of the time period. The WTRU transmission may continue into the next time period.

[0131] In an example, the time period may be an SF, and the time unit may be a symbol. The WTRU may determine whether the channel may be free for transmission, e.g., at the beginning of the first symbol in the first SF. The WTRU may determine whether the channel may be free for transmission (e.g., if the channel is not free) at the beginning of the second symbol (e.g., the next symbol) in the first SF. The WTRU may transmit (e.g., if the channel is free), e.g., starting with the second symbol in the first SF. The WTRU may start transmitting a transport block (TB) in the second symbol of the first SF. The last symbol for transmission of the TB may be a symbol in the first SF, such as the last symbol or the penultimate symbol in the first SF. The last symbol for transmission of the TB may be a symbol in a second SF, such as a subsequent SF, next SF, or next adjacent SF, among other examples.

[0132] In an example, the time unit may be an sTTI, which may consist of a set of symbols.

[0133] The WTRU may determine the duration for a transmission based on, for example, a start point or time and / or an end point or time of the transmission. The start point or time may be determined by the WTRU based on, for example, the results of the CCA. The start point or time may be selected by the WTRU from, for example, a set of start points or times that may be configured and / or allowed. The end point or time may be fixed, configured, or known. The end point or time may be selected by the WTRU from, for example, a set of end points or times that may be configured and / or allowed. The WTRU may determine the duration of the transmission from, for example, a set of durations that may be configured and / or allowed.

[0134] The WTRU may determine (e.g., based on the start point or time, end point or time, or duration (e.g., determined duration) of the transmission), for example, (i) an amount of data to transmit, such as a TB size (TBS), (ii) one or more frequency resources to use for the transmission, and / or (iii) a set or pattern of frequency resources, such as REs, RBs, or PBs, to use for the transmission.

[0135] Frequency resource adaptation may be provided. The WTRU and / or eNB or gNB may determine the frequency resources for a transmission based on, for example, a start point or time and / or an end point or time of the transmission.

[0136] In an example, a WTRU may transmit on a larger set of frequency resources, e.g., if there is potentially less time to transmit. The WTRU may determine, e.g., a start time, an end time, and / or a duration for the transmission. The WTRU may determine the number of resources and / or sets of resources based, e.g., on the start time, end time, and / or duration of the transmission.

[0137] The WTRU may use a fixed number of time and / or frequency resources to transmit a transport block. The WTRU may select a numerology based on, for example, the amount of time remaining in a transmission occasion from the moment the WTRU may have acquired the channel. In an example, the WTRU may select a first subcarrier spacing and / or a first symbol duration, for example, if the WTRU is able to acquire the channel at a first time instance, where T1 time may remain for transmitting a TB. The WTRU may select a second subcarrier spacing and / or a second symbol duration when the WTRU may fail to acquire the channel at the first time instance and (e.g., instead) acquire it at a second time instance, where T2 time may remain for transmitting a TB. The WTRU may select a larger subcarrier spacing and / or a smaller symbol duration (e.g., during the remaining T2 time) for its transmission, for example, if T2 may be less than T1. A WTRU can be configured with a set of applicable and / or valid subcarrier spacing and / or symbol duration values ​​that can be used for or within unlicensed channels. The configuration can be provided, for example, via a broadcast transmission (e.g., in a system information transmission) or via a configuration that can be for grant-free transmission. The configuration can be, for example, group-specific or WTRU-specific and can be provided and / or received via group-specific or WTRU-specific signaling.

[0138] The number of symbols used may be the same, for example, regardless of the start time and / or duration. Subcarrier spacing may be determined based on the start time and / or duration. In an example, one (e.g., the same) physical channel structure (e.g., reference signal structure and data RE location) may be used for different start times and / or durations.

[0139] The CP length may be the same for (e.g., all) subcarrier spacing candidates. The (e.g., maximum) CP length can be determined (e.g., alternatively) based on, for example, the subcarrier spacing. The WTRU, eNB, or gNB can drop a transmission if, for example, the CP length due to channel conditions is likely to be longer than the maximum CP length.

[0140] The resources may be time resources and / or frequency resources. The resources may be resource blocks (RBs) or physical resource blocks (PRBs). The resources may be, for example, contiguous in frequency (e.g., contiguous subcarriers). The resources may be distributed in frequency, for example, across a band or subband of frequency.

[0141] A set (e.g., a candidate set) of RBs, PRBs, and / or frequencies (e.g., from which the WTRU can determine a subset for transmission) may be configured. In an example, the WTRU may receive one or more sets (e.g., a candidate set) of resources (e.g., a pattern of resources) from which the WTRU can select a set or subset (e.g., a candidate) for transmission. The WTRU may determine a candidate from the candidate set to use for transmission based, for example, on the time available for transmission.

[0142] The WTRU may map modulated symbols of a transport block (TB) to time / frequency resources (e.g., resource elements (REs)) that may correspond to a determined candidate from a set of candidates. The WTRU may apply repetition of a certain number of modulated symbols (e.g., a small number of symbols), for example, if the number of REs in the selected candidate may be greater than the number of modulated symbols of the TB.

[0143] In an example, unlicensed transmissions in a band (e.g., 5 GHz) may include interlaced transmissions across all transmission sub-bands within that band (e.g., 5 MHz or 20 MHz sub-bands). The candidate set of resources may be an interlacing pattern from which the WTRU can make a selection. An extension in frequency resources (e.g., a set with more frequency resources) may accommodate denser interlacing patterns.

[0144] The use of denser interlaces may result in the WTRU having more (e.g., many more) available REs for transmission than may be necessary for the current TB. The WTRU may transmit additional TBs (e.g., with smaller TBSs) in the remaining available REs.

[0145] A MIMO transmission scheme that can be used for transmission can be determined, for example, based on the (e.g., determined) frequency resource candidates and / or start times and durations. For example, if a first frequency resource candidate can be determined, a first MIMO transmission scheme (e.g., space frequency block coding (SFBC)) can be used. For example, if a second frequency resource candidate can be determined, a second MIMO transmission scheme (e.g., precoder cycling) can be used. The first frequency resource candidate can have a smaller number of frequency resources than the second frequency resource candidate.

[0146] The MIMO transmission scheme may be determined based on, for example, the number of RBs or PRBs in the frequency resource candidate. The first MIMO transmission scheme may be used, for example, if the number of RBs or PRBs in the frequency resource candidate is likely to be greater than a threshold, while the second MIMO transmission scheme may be used, for example, if not.

[0147] The transmission rank (e.g., the number of layers) may be determined based on, for example, the (e.g., determined) frequency resource candidates and / or the start time and duration. For example, if a first frequency resource candidate can be determined, a first transmission rank may be used, while, for example, if a second frequency resource candidate can be determined, a second transmission rank may be used.

[0148] The receiver may determine the frequency resources used in the transmission. The WTRU may transmit a reference signal (RS), such as a demodulation reference signal (DM-RS), in its transmission. The WTRU may transmit the RS in the PRBs of the transmission (e.g., in a subset of the REs of the transmission), which allows the eNB to determine a set of resources (e.g., a candidate set) to use for the transmission. The eNB may use the RS transmission, for example, to determine candidate or set of frequencies used by the WTRU to transmit.

[0149] A minislot may be a time unit that may contain fewer symbols than a slot. In an example, a slot may contain seven symbols, while a minislot may contain two, three, or four symbols.

[0150] The WTRU may transmit an RS at a position within a time unit (e.g., a subframe, a slot, or a minislot), where, for example, the position may be fixed, known, or configured. The WTRU may transmit an RS at a position within a time unit that may be determined by the WTRU. The RS may have or be transmitted at a position that may, for example, be a nominal, default, or regular position. The WTRU may transmit an RS at a position that may not be a nominal, default, or regular position. An RS transmission may be considered a flexible RS transmission, for example, if it may be transmitted at a nominal, default, or regular position, or may not be transmitted, for example, based on one or more criteria. The criteria may be a function of when the WTRU can gain access to the channel, for example.

[0151] A WTRU may, for example, use (e.g., be configured to use) a minislot if it is able to gain access to the channel (e.g., initially). A WTRU may, for example, use a flexible RS (e.g., DM-RS) transmission if it is able to use a minislot for (e.g., initial) transmission.

[0152] An RS (e.g., DM-RS) that may be associated with a minislot may be used by the eNB to determine a candidate set of resources (e.g., frequency resources) from which the WTRU may be transmitted. The RS may be (e.g., may also be) used by the eNB to determine, for example, a start time of transmission.

[0153] A WTRU may use a slot (e.g., a regular slot) or a minislot, for example, based on the time the WTRU is able to gain access to the channel. In an example, a WTRU may determine to use a slot (e.g., a regular slot) for transmission if the WTRU is able to gain access to the channel within a certain number of symbols, e.g., two symbols (e.g., OFDM or DFT-spread-OFDM (DFT-s-OFDM) symbols), from the beginning of a subframe. A subframe may include, for example, two slots. The WTRU may use, for example, at least one (e.g., the first) slot and may transmit, for example, in a symbol of the slot that occurs after the WTRU is able to gain access to the channel. The WTRU may transmit an RS at its nominal, regular, or default location if that location may be (e.g., is) included within a symbol of the transmission (e.g., the fourth symbol of a slot).

[0154] In (e.g., another) example, a WTRU may use a minislot for its first transmission, e.g., if the WTRU can gain access to the channel a certain number of symbols (e.g., four symbols) after the beginning of a subframe, or if the WTRU can gain access to the channel after the nominal, regular, or default position of the RS. The WTRU may transmit the RS in one or more symbols of the minislot according to a minislot configuration, which may, e.g., be received, determined, and / or indicated.

[0155] The eNB may determine a candidate set that may be used based on, for example, the start and / or end points or times of the transmission. The eNB may blindly detect the start and / or end points. The eNB may receive an indication from the WTRU, for example, to aid it in determining the start and / or end points of the transmission.

[0156] The DM-RS may be transmitted at the end time of the transmission (e.g., in one or two last symbols). The frequency resource for the DM-RS transmission may be the same, for example, regardless of the frequency resource candidate that may be determined for the transmission. In an example, a nominal bandwidth for the transmission may be used for the DM-RS transmission. The nominal bandwidth may be, for example, the frequency resource candidate that may be used with respect to a reference start time and / or duration (e.g., a time period).

[0157] One or more sequences may be used for the DM-RS. The number of sequences used may be determined based on, for example, the number of frequency resource candidates. One (e.g., each) sequence may correspond to one frequency resource candidate.

[0158] A sequence corresponding to a frequency resource candidate may be used for a transmission, for example, when the eNB, gNB, or WTRU is able to determine the frequency resource candidate based, for example, on the start and duration of the transmission.

[0159] The receiver may, for example, detect (eg, blindly) the sequence of DM-RS transmitted at the end of the transmission to determine the candidate frequency resources to be used.

[0160] For example, if the determined frequency resource may be wider than the nominal frequency resource, one or more (eg, additional) DM-RSs in frequency may be used.

[0161] For example, if the duration may be longer than a reference duration (eg, a time period), one or more (eg, additional) DM-RSs in time may be used.

[0162] The DM-RS may (e.g., alternatively) be transmitted at the end time of transmission, which may be aligned regardless of the frequency resource candidates. The frequency resources for the DM-RS may differ, for example, based on the frequency resource candidates. In an example, the DM-RS may be transmitted on the frequency resources. The DM-RS sequence and / or sequence length may be determined, for example, based on the determined number of frequency resources. The receiver may, for example, detect the DM-RS sequence (e.g., blindly) to determine the frequency resource candidates used for transmission.

[0163] A maximum power constraint may be provided. The WTRU may exceed the maximum power (e.g., a configured maximum output power), for example, when using additional frequency resources. The WTRU may take one or more actions to avoid violating the power constraint, such as by exceeding the maximum power or maximum EIRP.

[0164] The WTRU may, for example, limit the candidates (e.g., when determining a set of frequency resources to use), e.g., to avoid exceeding a maximum power or EIRP. The WTRU may (e.g., alternatively) adjust the power of one or more channels to be transmitted, e.g., to avoid exceeding a maximum power or EIRP.

[0165] The eNB may use the latest power headroom report, for example, to determine the most likely set to be used in a transmission (eg, for purposes of blind decoding frequency resources).

[0166] The WTRU may determine a set of frequency resources to use for transmission. For example, if the WTRU is likely to use a set of frequency resources (e.g., for a short transmission) that may result in the WTRU exceeding maximum power, the WTRU may behave as if the channel is determined to be busy and check the channel availability at the beginning of a subsequent (e.g., next) time period.

[0167] In an example, the WTRU can perform CCA for a first time unit (e.g., within a time period) whose transmission time can be Tbase. For example, if the WTRU can determine that the channel is free, the WTRU can use a first set of frequency resources for transmission. For example, if the WTRU can determine that the channel is busy, the WTRU can try again in a second time unit (e.g., within the time period) whose transmission time can be Tshort (in this case, Tshort < Tbase). For example, if the WTRU can determine that the channel is free, the WTRU can use a second set of frequency resources for transmission (e.g., the second set of resources can include more resources than the first set of resources).

[0168] For example, if the WTRU determines that transmission on the second set of frequency resources may violate a power constraint (e.g., maximum power or EIRP) (e.g., will violate), the WTRU can skip the transmission for the second time unit (e.g., starting at the second time unit). The WTRU can try again (e.g., perform CCA and transmission if the channel is free) for a subsequent (e.g., next) time unit within the time period, or try again for a subsequent (e.g., next) time period. The WTRU can (e.g., by proceeding to the subsequent time period) result in the WTRU having more time for transmission and using fewer frequency resources that can avoid exceeding the maximum power.

[0169] The WTRU may determine that transmission on the second set of frequency resources may violate the transmit power constraint. The WTRU may (e.g., alternatively) search for and / or determine (e.g., among one or more candidates) a smaller TBS and / or a lower modulation order that may enable the WTRU to meet the transmit power constraint. The WTRU may transmit using the TBS and modulation order. The TBS may be, for example, the original TBS or the determined smaller TBS. The modulation order may be, for example, the original modulation order or a lower modulation order. The one or more candidate TBSs and modulation orders may be predefined or configured. A DM-RS that may be transmitted on the frequency resources may be used, for example, to indicate which TBS and / or modulation order may be used.

[0170] A time unit can be, for example, a scheduled, configured, or assigned time unit. A time period can be, for example, a scheduled, configured, or assigned time period.

[0171] The WTRU may request the channel, e.g., for the duration of Tshort, until (e.g., alternatively) the beginning of a subsequent (e.g., next) time period and / or until it can transmit for a longer period of time and / or use fewer frequency resources. The WTRU may, for example, transmit a reference signal or other signal within the first or second set of frequency resources to request the channel. The WTRU may transmit in the next time period (e.g., at the beginning of the next time period).

[0172] Beam sweeping adaptation may be provided. The WTRU may perform UL Tx beam sweeping operations and / or retransmissions, for example, to enable UL Rx beam sweeping operations (e.g., when transmitting in an unlicensed channel or band). Retransmissions may include, for example, repetitions (e.g., of the same data). Retransmissions may include, for example, multiple transmissions on the same Tx beam or in the same direction. The multiple transmissions may or may not be the same (e.g., the same data). The WTRU and / or gNB may have limitations on the number of beams that may be used simultaneously. The WTRU may repeat a transmission over multiple symbols. In an example, the WTRU may transmit a TB over a symbol and repeat the transmission over multiple symbols (e.g., of a slot). Repetitions may enable or be used for Tx and / or Rx beam sweeping, for example. The number of symbols of a transmission, which may be part of the set of repeated transmissions, may be constant. In an example, the number of symbols may be the same for one or more (eg, all) of the transmissions in the set of repeated transmissions.

[0173] The WTRU may select the subcarrier spacing based on, for example, the amount of time remaining in the transmission opportunity or based on the time the WTRU may have acquired the channel. The WTRU may be configured with a set of subcarrier spacing values ​​that may be applicable for transmission on the channel.

[0174] The overall transmission bandwidth may have limitations (e.g., due to a maximum power constraint). The WTRU may reduce the symbol time (e.g., increase the subcarrier spacing) until it achieves the maximum bandwidth. The WTRU may modify the rate at which it can repeat transmissions. In an example, the WTRU may map a complete TB to a symbol (e.g., for a first subcarrier spacing) and repeat the transmission over adjacent symbols (e.g., while changing its UL transmit beam). The WTRU may map a complete TB to a set of one or more symbols (e.g., two symbols) (e.g., for a second subcarrier spacing) and repeat the set of symbols over adjacent symbol sets. This may reduce the number of beams over which the WTRU can sweep transmissions. The WTRU may, for example, adapt the beamwidth of one (e.g., each) individual beam over which it can transmit data repetitions to enable the WTRU to sweep over an appropriate total beamwidth. The adaptation may be based on the total number of available repetitions in a transmission opportunity.

[0175] Data size adaptation may be provided. In an example, the transport block size (TBS) may be adapted. The TBS may be the same for one or more (e.g., all) candidate sets of resources. One (e.g., each) candidate set of resources may be (e.g., alternatively) associated with a TBS. The WTRU may, for example, transmit on a set of resources (e.g., a set determined from the candidates) using the associated TBS.

[0176] The WTRU and / or eNB may determine the amount of data (e.g., TBS) for transmission based on, for example, a start point or time of the transmission, an end point or time of the transmission, and / or a duration of the transmission. The amount of data (e.g., TBS) may be determined based on, for example, a candidate set of resources (e.g., frequency resources) used for the transmission, for example, using the number of PRBs in the resource set used for the transmission.

[0177] The WTRU may not have enough time to build or rebuild the TB before transmission, for example, if the size may vary depending on when the WTRU is able to start transmitting.

[0178] The WTRU may prepare a set of transport blocks having sizes that may correspond to one or more possible start times, durations, and / or frequency resource sets. The WTRU may use prepared TBs that may align with (e.g., autonomously) determined start times, durations, and / or frequency resource sets.

[0179] For example, if preparing multiple TBs in advance may not be the optimal solution, code block segmentation may be used. The number of code blocks to transmit may be determined based on, for example, the time available for transmission.

[0180] In an example, the WTRU may determine the number of code blocks to transmit based on, for example, a start point or time of the transmission, an end point or time of the transmission, and / or a duration of the transmission. The number of code blocks may be determined and / or selected by the WTRU, for example, from a candidate set or a configured set.

[0181] A receiver (e.g., an eNB) can determine the number of code blocks to be transmitted based on, for example, a start point or time of the transmission, an end point or time of the transmission, and / or a duration of the transmission.

[0182] The WTRU may not be able to transmit all code blocks (CBs) of a TB in a transmission opportunity (e.g., slot). The WTRU may hold (e.g., all) CBs (e.g., transmitted and untransmitted) of a TB (e.g., in cases where retransmission of a CB or CB group (CBG) may be possible) and may wait, for example, for the gNB to provide HARQ feedback (e.g., CBG-level HARQ feedback) or a CBG-level UL grant to transmit the remaining CBs.

[0183] In an (e.g., alternative) example, the WTRU may adapt a TB transmission to fit into multiple (e.g., two) adjacent minislots (e.g., TB segmentation over multiple slots or minislots). The first minislot size may be adapted, for example, to include a first set of CBs that may be transmitted from the time the WTRU can acquire the channel until a transmission boundary. The second minislot size may be adapted to allow transmission of the remaining set of CBs (e.g., over a predetermined bandwidth). The second minislot may be transmitted, for example, immediately after transmission of the first minislot (e.g., if the MCOT may not have been exceeded). The WTRU may transmit a subsequent TB (e.g., upon completion of transmission of the second minislot, such as for the first TB), which may be transmitted over a default, pre-configured, or predetermined slot size (e.g., if the MCOT may not have been exceeded). In one (e.g., alternative) example, the slot size used by the WTRU for the remainder of its channel occupancy may be a function of the slot size that may be used in, for example, the first and / or second minislot transmissions.

[0184] In an (e.g., alternative) example, a WTRU may be configured to use a minislot, e.g., when it accesses a channel (e.g., initially), and may revert to using a slot (e.g., a regular slot) for subsequent back-to-back transmissions. The WTRU may decide to use a minislot or a slot (e.g., if the channel can be assessed as available), e.g., based on the starting point of the transmission. The WTRU may determine the size of the minislot (e.g., 2, 3, 4 symbols), e.g., based on the starting point of the transmission.

[0185] In (e.g., alternative) examples, the WTRU may split the TB to be transmitted into multiple (e.g., two) codewords. The WTRU may decide to transmit multiple codewords, shorter codewords, or longer codewords based, for example, on the starting point of the transmission and / or the duration of the transmission.

[0186] The WTRU may be granted UL resources to transmit another TB in the second slot (e.g., in a grant-based transmission). The WTRU may be prevented from transmitting the second TB (e.g., in this case), e.g., using a minislot, e.g., to complete the transmission of the first TB. The prevention may lead to the second TB transmission including segmentation into multiple (e.g., two) minislots and / or the prevention of a third TB transmission, etc.

[0187] The WTRU may include a DM-RS and / or another reference signal in one (e.g., each) slot, regardless of slot size, e.g., if one or more TBs may be segmented across multiple minislots. In (e.g., alternative) examples, the WTRU may include one or more (e.g., all) reference signals in one or more slots (e.g., only those slots), e.g., for a transmission with one or more segmented TBs. The inclusion of reference signals may be statically or semi-statically configured (e.g., with a grant-free transmission configuration), determined by the WTRU, and / or indicated to the gNB.

[0188] Control channel adaptation may be provided. The type or size of the UL control channel (e.g., PUCCH) may depend on the amount of time available for transmission, e.g., PUCCH alone or combined with PUSCH transmission. PUCCH may be repeated in time and / or frequency, e.g., to improve PUCCH coverage.

[0189] The resources for the transmission and / or repetition of the PUCCH may be selected and / or determined from a candidate resource set that may be configured. The resource set may be selected and / or determined based on, for example, the time available for transmission.

[0190] The PUCCH type may (e.g., alternatively) depend on, for example, the amount of time available for transmission. In an example, a first PUCCH type (e.g., a DM-RS-based PUCCH) may be used for a first candidate resource set, and a second PUCCH type (e.g., a sequence-based PUCCH) may be used for a second candidate resource set. The first candidate resource set may have a longer duration than the second candidate resource set. One or more of the following may apply: The first PUCCH type (e.g., a DM-RS-based PUCCH) may provide higher multiplexing capacity, while performance may be worse than the second PUCCH type (e.g., a sequence-based). The second PUCCH type may provide better performance, while providing lower multiplexing capacity. The candidate resource sets for the first and second PUCCH types may not overlap in frequency.

[0191] The content of the PUCCH transmission can vary, for example, based on a delayed start of the PUCCH transmission, for example, due to the channel being determined to be busy. In an example, for example, if the transmission can start in a first time unit or time period, a first content can be transmitted. For example, if the transmission can be delayed to a second time unit or time period, for example, due to the channel being determined to be busy for the first time unit or time period, a second content can be used.

[0192] In an example, the second content may include ACK / NACK (A / N) information for more DL transmissions than the first content, e.g., if the window of time covered by the delayed PUCCH can cover the A / Ns for more DL transmissions.

[0193] In an example, the first content may include A / Ns for the first, second, and third DL transmissions. The second content may include A / Ns for the first, second, third, and fourth DL transmissions. For example, if a delay from the first time unit or period to the second time unit or period for the HARQ timing for the DL transmission can warrant adding A / N information for another possible DL transmission, the fourth A / N information may be included.

[0194] In (e.g., another) example, the first content may include an A / N and a CQI. The second content may include, for example, an A / N without a CQI. The CQI may be dropped, for example, based on time available for transmission. The CQI may be dropped, for example, if there may not be room to transmit the CQI in the PUCCH, for example, if the PUCCH may be shortened. The PUCCH may be shortened, for example, based on time available for transmission, which may be a function of when the channel may be determined to be free for transmission.

[0195] Transmission time start points may be configured. A WTRU may be configured with a set of transmission start points, which may correspond to, for example, a time unit or time period. A time unit may be within one or more time periods. In an example, a WTRU may be configured with a set of symbols, which may be within a subframe in which the WTRU may transmit or start transmitting.

[0196] A set of time units (e.g., symbols) within a time period (e.g., a subframe) at which a WTRU can start transmitting may be configured. The configuration may be provided by higher layer (e.g., RRC) signaling. The configuration may be provided in a DCI. The DCI may include an UL grant for transmission. The DCI may be a common DCI, e.g., it may be intended for or used by one or more WTRUs. The DCI may include, e.g., a trigger to enable UL transmission, e.g., after grant parameters may be provided (e.g., individually).

[0197] The WTRU may determine that the channel may not be clear before the first starting point (e.g., for grant-based or grant-less access). The WTRU may try again for one or more (e.g., each) of the next starting points in the set of starting points, for example, until the WTRU can determine that the channel is free for transmission. The WTRU may transmit (e.g., starting at the starting point), for example, if the WTRU can determine that the channel is free for the starting point.

[0198] The transmission time can be shortened. The end of the transmission in a time period can be fixed or configurable. In an example, the transmission can end at the last time unit of the time period or at another configured time unit within the time period.

[0199] The amount of time available for transmission can be, for example, a function of the starting point of the transmission in the time period.

[0200] In an example, a transmission starting at a first time unit within a time period may result in T1 time for transmission, and a transmission starting at a second time unit within the time period may result in T2 time for transmission. For example, if the second time unit may be after the first time unit, T2 may be less than T1. For example, if CCA may fail for the first time unit and pass for the second time unit, such that the WTRU begins transmitting for the second time unit, the WTRU may have even less time to transmit (e.g., T2 time instead of T1 time).

[0201] The transmission time (e.g., maximum transmission time) can be fixed or configurable. The transmission time can be, for example, the length of a time period, TTI, which can be configured or can be the scheduled, allowed, or assigned time or TTI for transmission.

[0202] The transmission time may start in a time unit, and the transmission time may be relative to the starting time unit, e.g., if the WTRU may start transmitting in a time unit that may not be at the beginning of the time period. The transmission may continue in the next time period, e.g., if the transmission time may be longer than the time from the time unit to the end of the time period.

[0203] The WTRU and / or eNB may determine the number of transport blocks that may be transmitted, which may be a function of the start point or time and / or end point or time of the transmission, for example.

[0204] The WTRU may be assigned or granted n, or up to n, time periods, TP1, TP2, ..., TPn. The WTRU may perform CCA. CCA may start before TP1. The WTRU may determine that the channel is free for transmission starting at time unit x, TUx, within time period k, TPk.

[0205] The WTRU may transmit the first transport block (TB) starting at TUx. The WTRU may determine the number of transport blocks, B, that it can transmit. The WTRU may, for example, transmit up to B transport blocks, where B≦N. In an example, B may be the number of transport blocks (e.g., complete transport blocks) that can be transmitted in a time period starting at TUx and ending at the end of TPn. The WTRU may, for example, release the channel after transmitting B transport blocks. The WTRU may, for example, release the channel before transmitting B transport blocks if the WTRU may have completed transmitting data or TB.

[0206] For example, if the transmission of the first TB may not (e.g., does not) start at the beginning of a time period, the first TB may be reduced in size (e.g., so that the transmission of the first TB can fit into the first time period). The remaining TBs that may be transmitted may be full size. The first TB and one or more subsequent TBs may (e.g., alternatively) be full size, with the last TB being reduced in size, e.g., to fit into the last portion of the last time period that may contain the transmission.

[0207] The amount of data that a WTRU may transmit, such as a transport block size (TBS), may be a function of the start and / or end points of the transmission.

[0208] In an example, the WTRU may perform CCA on a transmission at the beginning of a symbol within the SF. The WTRU may try again at a subsequent symbol, which may be within the SF (e.g., if the CCA may fail). The WTRU may transmit starting at a subsequent symbol, for example, if the WTRU may determine that the CCA passes.

[0209] For example, if the WTRU is able to try again in a subsequent time unit (e.g., symbol), a full CCA may be used. The full CCA may not be a new CCA. The full CCA may be a continuation of a full CCA that may have been performed before a previous time unit (e.g., symbol). In an example, the WTRU may perform a (e.g., full) CCA and, following a determination that the channel may be free, may start transmitting in the first symbol within the granted or assigned time resource.

[0210] An indication of the start time and / or end time may be provided, which may be detected, for example, by blind decoding. The eNB may use blind decoding or assistance from the WTRU's transmission, for example, to receive and / or decode the transmission, which may have one or more flexible boundaries or patterns in time and / or frequency.

[0211] In an example, an eNB may determine (e.g., based on blind detection) the beginning and / or end of a transmission it may receive. The blind detection may include, for example, attempting to receive and / or decode one or more candidate transmission sizes. A transmission may be considered successfully received and / or decoded if, for example, the CRC may be determined to be correct. The transmission size may include, for example, a number of time units and / or time periods. The candidates may include, for example, a time component and a frequency component for the transmission, where the number and / or pattern of frequency resources may be adapted, for example, based on the length of the transmission in time.

[0212] The WTRU may provide an indication and / or assistance. In an example, a reference signal may be transmitted and / or used to indicate the beginning and / or end of a transmission.

[0213] In an example, the WTRU may transmit a first reference signal, e.g., to indicate the beginning of a transmission. The WTRU may transmit the reference signal, e.g., in at least one time unit of a transmission. In an example, the reference signal may be transmitted in (e.g., at least) the first time unit of a transmission.

[0214] The WTRU may transmit a second reference signal, for example, to indicate the end of a transmission. The WTRU may transmit the reference signal in one (e.g., at least one) time unit of a transmission. In an example, the reference signal may be transmitted in (e.g., at least) the last time unit of a transmission.

[0215] The WTRU may transmit a first and / or second reference signal for the transmission. The first and second reference signals may be the same or different.

[0216] The beginning, such as a start time (e.g., a start time unit or time period) of a transmission, can be, for example, one of a set of beginnings that can be configured. The start time can be a start time unit within a time period.

[0217] The end, such as an end time (e.g., end time unit or time period) of the transmission, can be one of a set of end times that can be configured. The end time can be an end time unit within the time period.

[0218] For example, if the frequency resources that can be used for transmission can be a determined subset from among a set of frequency resources, the reference signal can be transmitted in a bandwidth or pattern that can exist independently of the subset selected or used.

[0219] The reference signal may (eg, alternatively) be transmitted, eg, repeated, over a bandwidth or pattern of a subset of frequency resources that may be used for transmission.

[0220] In an example, the first subset may include a set or pattern of F1 frequency resources, and the second subset may include a set or pattern of F2 frequency resources. The F1 resources may be a subset of the F2 resources. For example, the WTRU may transmit a reference signal in the F1 resources when transmitting using the F1 resources. For example, the WTRU may transmit a reference signal in the F1 resources when transmitting using the F2 resources. In (e.g., alternative) examples, the WTRU may not transmit a reference signal in resources that may be in F2 but not in F1 when transmitting using the F2 resources. In a (e.g., alternative) example, the WTRU may transmit a reference signal in resources that may be in F2 but not in F1 when transmitting using the F2 resources. The transmission may be a repetition or extension of the transmission in the F1 resources.

[0221] Transmission of reference signals within a set or pattern of resources (eg, F1 or F2) may be within a subset of resources, eg, within a set of REs within a resource or RB.

[0222] A reference signal that may be used to indicate a time reference may be referred to as a time reference signal (TRS).

[0223] The WTRU may include a control channel, for example, at the beginning of a transmission. The control channel may include, for example, an indication of the length or duration of the transmission (e.g., in time).

[0224] The location of the control channel in frequency may be based, for example, on a minimum set of frequency resources that may be used for transmission.

[0225] In an example, for example, where the frequency resources that can be used for transmission can be a determined subset from among a set of frequency resources, the control channel can be transmitted in a bandwidth or pattern that can exist independently of the subset selected or used.

[0226] The control channel may (e.g., may also) indicate a set of frequency resources that may be used (e.g., a candidate set selected from a configured set of candidates).

[0227] The WTRU may take or perform measurements, which may be energy detection measurements, e.g., when performing channel assessment, e.g., to determine whether the channel is likely to be clear. The energy detection or measurements may be performed over a band or set of frequencies, which may include one or more (e.g., all) candidate frequency sets. The WTRU may compare the measurements or detected energy to a threshold, e.g., to determine whether the channel is likely to be free or busy.

[0228] A candidate frequency set may be a subset of another candidate frequency set. A frequency set may, for example, include one or more (e.g., all) other candidate frequency sets. A maximum frequency set may, for example, include one or more (e.g., all) other candidate frequency sets.

[0229] The WTRU may perform channel assessment for a band or set of frequency resources, which may be or may include a maximum frequency set.

[0230] The frequency or band or set of frequency resources over which the WTRU is able to perform CCA may be larger than the frequency or band or set of frequency resources over which the WTRU is able to transmit.

[0231] The WTRU may not know on which frequencies the WTRU can (e.g., will) transmit (e.g., at the time it may perform CCA). In an example, the WTRU may perform CCA for a first time unit, during which there may be T1 time to transmit. The WTRU may transmit on resource set R1 (e.g., during T1 time). For example, if CCA fails in the first time unit (e.g., if the WTRU may determine that the channel is busy), the WTRU may determine whether the channel is free for transmission in the second time unit. For example, for a transmission that may start in the second time unit, there may be T2 time to transmit (e.g., in this case, T2 may be less than T1). The WTRU may transmit on resource set R2 (e.g., during T2 time). R2 may include more frequency resources than R1. R2 may span more frequencies than R1. R1 plus R2 may span more frequencies than R1.

[0232] The WTRU may, for example, perform CCA on a band or set of frequencies that may include frequency resources in at least sets R1 and R2 to ensure that a CCA backoff / wait time can be respected (e.g., is respected).

[0233] In an (e.g., alternative) example, the WTRU may perform multiple energy detection measurements across a band or set of frequencies, which may include one or more candidate frequency sets. The multiple energy detection measurements (e.g., each of them) may be for a subset of the band. In an example, the subsets may overlap and may not be orthogonal. In an (e.g., another) example, one (e.g., each) subset may be disjoint and / or the set of all subsets may include the entire band. The WTRU may, for example, determine a channel assessment value for each transmission bandwidth (e.g., at any time) for transmission based on measurements across the band and the subset of the (e.g., required) transmission bandwidth. In an example, the band may be segmented into n subbands on which the WTRU may obtain n energy detection measurements. The WTRU may perform CCA, for example, by obtaining n energy detection measurements on the n subbands for a first time instance, during which the T1 time for transmission may be. The WTRU may need resource set R1 (e.g., for such transmission). The WTRU may perform a search across one or more (e.g., all) combinations of the n subbands that may comprise the R1 resource, e.g., to determine whether any combination of subbands can satisfy clear channel assessment. The WTRU may limit the search to, e.g., a contiguous set of subbands forming R1. The WTRU may (e.g., alternatively) limit the search to, e.g., a non-contiguous set of subbands forming R1.The WTRU may attempt CCA by (e.g., again) obtaining n energy detection measurements on the n subbands for a second time instance when there may be T2 time to transmit (e.g., if CCA may fail) and the transmission may use resource set R2. The WTRU may, for example, search across one or more (e.g., all) combinations of the n subbands that may include R2 resources to determine whether any combination of subbands can satisfy clear channel assessment.

[0234] A WTRU may be configured to puncture out (e.g., not use or not measure on) one or more subbands, for example, if the WTRU is capable of performing CCA. The subbands may be allocated or used for other WTRUs or other types of WTRUs. In an example, for unlicensed spectrum, N DL N PRBs can be used, determined, or configured. DL A subset of PRBs can be excluded from energy detection. The subbands or PRBs to exclude can be configured.

[0235] The subset of PRBs that can be punctured out of a CCA can be configured (e.g., via higher layer signaling) or determined (e.g., based on time period number, time unit number, cell ID, and / or number PRBs).

[0236] A subset of PRBs that may be punctured out from the CCA may not be used for transmission. In an example, a WTRU may not signal on a subset of PRBs, e.g., if the WTRU may be scheduled for uplink transmission and one or more scheduled PRBs may overlap with a subset of PRBs that may be punctured out from the CCA.

[0237] The energy threshold for determining whether a channel can be occupied can be based, for example, on the number of PRBs that can be punctured out from the CCA. In an example, an offset can be used with respect to the energy threshold. The offset can be determined, for example, based on the number of PRBs that can be punctured out from the CCA.

[0238] The maximum allowed transmit power may be determined, for example, based on the number of PRBs that may be punctured out from the CCA.

[0239] The WTRU may perform CCA on one or more sets of frequencies, where one (e.g., each) set of frequencies may be configured with a numerology, waveform, and / or transmission scheme.

[0240] One (e.g., each) set of frequencies can be configured with an energy threshold for CCA, which can depend on the waveforms that can be used in the set of frequencies.

[0241] The CCA capabilities of a WTRU may provide flexible transmission boundaries. Different WTRUs may have different capabilities for performing CCA. A WTRU may have and / or report capabilities, for example, regarding the time granularity at which the WTRU is able to perform one or more (e.g., consecutive) CCAs.

[0242] A WTRU may have, provide, and / or report (e.g., to an eNB) its capability to perform CCA. The capability may indicate, for example, how often and / or on what time boundaries the WTRU may or may be able to perform CCA, for example, in terms of time units or time periods.

[0243] In an example, the WTRU may perform or be able to perform CCA with respect to (eg, start transmission on) a time unit boundary or a time period boundary.

[0244] The WTRU may or may be able to perform CCA on adjacent or consecutive time unit boundaries. The WTRU may not or may not perform CCA on adjacent or consecutive time unit boundaries.

[0245] A WTRU that may not perform CCA on adjacent or consecutive time unit boundaries may, for example, perform CCA once per time period. In an example, for example, if the WTRU may determine that the channel may not be clear during a time period (e.g., during a time unit of the time period), the WTRU may not try again until another or next time period (e.g., during another or next time unit of the time period).

[0246] A WTRU that is capable of supporting (e.g., only supporting) CCA over a time period may, for example, for grant-based transmission, perform CCA over a time period (e.g., SF) and not perform CCA over a time unit (e.g., slot or symbol), or may be scheduled (e.g., only scheduled) to do so.

[0247] A WTRU that is capable of supporting (e.g., only supporting) CCA over a time period may, for example, for grant-free transmissions, perform (e.g., only perform) CCA over a time period (e.g., over one time unit per time period, such as over one symbol position per time period or SF).

[0248] Performing CCA on time periods instead of time units may delay transmission but may allow the WTRU to sleep longer.

[0249] The time granularity at which a WTRU can perform CCA may depend, for example, on the numerology of the expected transmission. In an example, it may be unnecessarily expensive for a WTRU that may be transmitting with large subcarrier spacing to perform CCA on adjacent or consecutive symbols. A WTRU may be configured with a time granularity that may depend on the subcarrier spacing of the intended transmission or on the default subcarrier spacing for the channel. The configuration may be provided, for example, via a broadcast transmission (e.g., in a system information block) or via group-specific or WTRU-specific configuration.

[0250] A determination may be made whether the channel is likely to be clear for transmission at the time boundary. The WTRU may, for example, perform CCA starting before the time boundary and / or for multiple time units and / or time periods before the time boundary to satisfy CCA requirements.

[0251] The configuration may be provided by a network node or element, such as, for example, an eNB, a gNB, a TRP, and / or a cell, among others. The WTRU may receive the configuration from a network node. The WTRU may receive the configuration, for example, via higher layer (e.g., RRC) signaling or broadcast signaling. The WTRU may receive the configuration via physical layer signaling, such as, for example, in a DCI. The configuration may be specific to a WTRU, a cell, a TRP, a beam, and / or a group of beams, among others.

[0252] A grant-free access resource pool may be provided. The resource pool may be used, for example, for grant-free transmissions. The resource pool may be a set of resources (e.g., time resources and / or frequency resources) that may be used by one or more WTRUs for transmission. The WTRU may, for example, determine or select a subset of resources from the resource pool to use for transmission.

[0253] The one or more resource pools may be configured and / or used by one or more WTRUs for grant-free transmissions. A WTRU may receive a configuration of resource pools that the WTRU may use for grant-free transmissions.

[0254] For example, if the WTRU is capable of using a subset of resources, the WTRU may perform CCA on a subset of resources from a resource pool. For example, if the WTRU is capable of being configured with one or more resource pools, the WTRU may (e.g., alternatively) perform CCA on a per-resource-pool basis.

[0255] The resource pool may be configured, for example, with a time schedule or pattern. The schedule or pattern may be periodic. The schedule or pattern may consist of a set of time units and / or time periods, e.g., consecutive time units, consecutive time periods, and / or a pattern of time units and / or time periods that may be repeated. The set of time units may be within a time period. The time unit, set of time units, or time period may be relative to a reference point, which may be beam-specific. In an example, the reference point may be the beginning or end of a synchronization burst (e.g., an SS burst) or a synchronization block (e.g., an SS block) that may be within a synchronization burst.

[0256] The repetition can be periodic. The repetition can have a duration after which the repetition can end. The repetition can continue, for example, until further configuration can indicate that the repetition can end (e.g., will end) or can no longer be used.

[0257] A resource pool that can be configured with a time schedule or pattern can be referred to as a semi-persistent scheduling (SPS) configuration.

[0258] A resource pool may be configured with one or more sets of resources, which may include time resources and / or frequency resources. The resources may be resource blocks (RBs) or physical resource blocks (PRBs). The resources may be contiguous in frequency (e.g., contiguous subcarriers). The resources may be distributed in frequency, for example, across a band or subband of frequency.

[0259] The use of SPS may mean that some resources may be dedicated for UL and not used for DL. This implication may not apply, for example, in scenarios using CCA. An eNB capable of performing DL transmission may, for example, perform CCA before the beginning of a time unit or time period (e.g., SF) in which there may be configured SPS resources. The eNB may, for example, select or use a channel for DL ​​transmission if the CCA is successful. For example, if the WTRU's CCA occurs long enough after the eNB has been able to start transmitting, the WTRU may consider the channel busy and not transmit in the UL.

[0260] The WTRU may, for example, adjust its UL timing based on the received DL timing. The WTRU may transmit a timing advance (TA) value before the corresponding received time unit or time period (e.g., for transmission of a time unit or time period in the UL).

[0261] The eNB may, for example, consider the cell size and / or TA when determining when to perform CCA and when to start transmission.

[0262] In an example, a 10 km cell size may correspond to a timing advance of approximately 67 μs. A symbol may correspond to, for example, approximately 67 μs. The eNB may perform CCA, for example, to start transmitting at least a symbol before the beginning of the resource pool, for example, to allow WTRUs in the cell (including, for example, WTRUs at the cell edge) to consider the channel busy before the beginning of the resource pool.

[0263] A resource pool may be configured with frequency resources (e.g., a set of RBs or PRBs) in a time unit or time period. For one or more resource pools, one or more frequency resources may be used. The frequency resources for a resource pool may be orthogonal to the frequency resources for another resource pool. The frequency resources for a resource pool may partially or fully overlap with the frequency resources for another resource pool.

[0264] A set of frequency resources may be configured for grant-free access. A frequency resource from the configured set of frequency resources for a resource pool may be determined based on, for example, a resource pool ID, a cell ID, a time unit number, and / or a time period number.

[0265] The frequency resource for the resource pool may be changed from a first time resource to a second time resource (eg, a time unit, a time period, or a slot).

[0266] The WTRU may perform CCA of frequency resources associated with the resource pool, which may be changed based on, for example, a time unit number, a time period number, and / or a slot number.

[0267] Resource pool allocation and WTRU identification may be provided. In an example, one or more resource pools may be configured and / or used.

[0268] A resource pool may be configured for a group of WTRUs. A WTRU may be configured with or allocated a group and / or resource pool. The eNB may perform the grouping. The eNB may inform the WTRU of the groups it may be in. In an example, the WTRU may be configured with the groups it may be in. The configuration may include a group ID. The WTRU may determine the resource pool to use, for example, based on the group or group ID.

[0269] A WTRU may be configured (e.g., allocated means for indicating) its identity in its transmissions. Indications of identity may be used within a group. In an example, a first indication may be used by a WTRU to identify itself in a first group, and a second WTRU may be used to identify itself in a second group. WTRUs may be distinguished by the eNB, for example, based on the resource pool used by the WTRU for transmission.

[0270] The WTRU may use a CRC mask, for example, to identify itself when it transmits. The mask may be configured by the eNB. The WTRU may mask (e.g., scramble) the CRC of its transmission with the mask. The mask may be, for example, an RNTI. The mask may be the WTRU's C-RNTI or a portion or function of the WTRU's C-RNTI. The mask may be received or configured, for example, separately from the WTRU's C-RNTI.

[0271] In an example, a WTRU may receive a first RNTI (e.g., its C-RNTI) for authorized access and a second RNTI for grant-free access. The mask or RNTI for grant-free access may be a different number of bits than the RNTI or CRC mask for authorized transmissions. In an example, the RNTI for authorized transmissions may be used to mask the CRC of a DCI that may be intended for the WTRU, for example, for purposes of providing a grant.

[0272] The WTRU may (e.g., alternatively) use the CRC masks to identify whether the WTRU buffer may be empty or not. In an example, a first CRC mask may be used (e.g., if the transmission may be the last transmission) and a second CRC mask may be used (e.g., if there may be a subsequent transmission).

[0273] The WTRU may, for example, use a WTRU-specific scrambling ID for the DM-RS sequence. In an example, the DM-RS sequence may be scrambled, for example, based on the WTRU-ID. The eNB (or gNB) may, for example, detect the DM-RS sequence (e.g., blindly) to identify the WTRU.

[0274] Resource pool tiers may be provided. There may be a set of resource pools, e.g., SPSs, that are configured. The set of resource pools may have different frequencies of occurrence or recurrence. A first tier of resource pools, e.g., tier 1, may occur less frequently than a second tier of resource pools, e.g., tier 2.

[0275] In an example, a tier 1 resource pool may have a first occurrence or recurrence frequency (e.g., every N1 time periods). A tier 2 resource pool may have a second occurrence or recurrence frequency (e.g., every N2 time periods). In an example, tier 1 resources may occur or recur less frequently than tier 2 resources. In an example, N2 may be less than N1 (e.g., a second tier of resources may recur more frequently than a first tier of resources).

[0276] The selection or use of a first-tier resource pool or a second-tier resource for transmission may be based, for example, on channel availability. In an example, the WTRU may (e.g., first) attempt to use one or more resources in the first-tier resource pool. For example, if the WTRU may determine that the channel may be busy (e.g., more than a threshold number of times while attempting to use the first resource pool), the WTRU may use or attempt to use one or more resources in the second-tier resource pool.

[0277] In an example, a WTRU may start with a first tier resource pool, e.g., tier 1. The WTRU may determine an upcoming tier 1 resource generation or allocation in which the WTRU may transmit. The upcoming resource generation or allocation may include a set of time units and / or time periods (e.g., n time periods). The WTRU may perform CCA, for example, before the first time period. The WTRU may determine whether the channel is likely to be free for transmission in the first time period. The WTRU may, for example, transmit in (e.g., at least) the resources in the first time period if the channel is likely to be free. The WTRU may determine whether the channel is likely to be free during one or more subsequent n-1 time periods in the resource generation or allocation (e.g., if the channel is not likely to be free). The WTRU may, for example, transmit starting from the first time period in which it may determine the channel is free.

[0278] The WTRU may try again at a subsequent (eg, next) occurrence of the resource pool (eg, if the channel is likely to be busy for the entire time period).

[0279] The WTRU may be unable to transmit using a first tier resource pool for a threshold number N of attempts, e.g., based on a determination that the channel may be busy. The WTRU may attempt to transmit using resources in a second tier resource pool, e.g., a more frequent resource pool. N may be the number of occurrences of the first tier resource pool. N may be the number of time units or time periods. The value of N may be configurable.

[0280] One or more resource pools or sets of resource pools may be configured and / or used. A resource pool or set of resource pools may be configured with a priority. Different resource pools or sets of resource pools may have or be configured with different priorities. In an example, a first tier resource pool, e.g., tier 1, may have or be configured with a higher priority than a second tier resource pool, e.g., tier 2. A WTRU may use (e.g., decide to use) a resource pool for a transmission based, for example, on the priority or type of transmission.

[0281] In an example, a first tier resource pool may be used for higher priority data or signal types (e.g., UCI, URLLC), while a second tier resource pool may be used for lower priority data or signal types (e.g., data, eMBB, mMTC).

[0282] In an example, a first layer resource pool may be used for retransmissions of a data channel, while a second layer resource pool may be used for the initial transmission, e.g., or vice versa.

[0283] For example, if a WTRU can be configured, determined, or indicated to transmit signals in a first tier resource pool and a second tier resource pool, the WTRU can transmit signals in multiple resource pools (e.g., if the uplink transmit power is not limited). The WTRU can drop or scale down signals for a second tier (e.g., lower priority) resource pool, for example, if the uplink transmit power can be (e.g., is) limited.

[0284] A first tier resource pool may be configured with a lower energy sensing threshold than a second tier resource pool, or vice versa. In an example, for example, an offset may be provided for the energy sensing threshold for the second tier resource pool relative to the energy sensing threshold for the first tier resource pool.

[0285] FIG. 2 is an example of a resource pool layer. The resource pool of layer 1 may, for example, include a set of n1 opportunities (e.g., every N1 time periods). The resource pool of layer 2 may, for example, include a set of n2 opportunities (e.g., every N2 time periods). The value of N2 may be smaller than the value of N1. The values ​​of N1 and N2 may or may not be the same. The opportunities may be transmission opportunities. The opportunities may, for example, include a set of time resources and / or frequency resources (e.g., RBs or PRBs). The transmission opportunities may include a set of transmission opportunities. The transmission opportunities of the resource pool may occur periodically or cyclically. In an example, the transmission opportunities of the resource pool of layer 1 may occur every N1 time periods. The transmission opportunities of the resource pool of layer 2 may occur every N2 time periods.

[0286] The opportunities within a transmission opportunity or within a set of opportunities may or may not be adjacent or consecutive in time. An opportunity may correspond to one or more time units and / or time periods. The opportunities within a transmission opportunity or within a set of opportunities may or may not correspond to the same duration or amount of time. The WTRU may perform CCA at the beginning of the opportunity, at one or more subsequent times during the opportunity, at the beginning of the opportunity, and / or at one or more subsequent times during the opportunity. An occasion may include, for example, an opportunity and / or an opportunity. An opportunity and an opportunity may be the same.

[0287] 3 is an example of resource pool tier selection and use. In this example, the WTRU may attempt (e.g., decide to) use a second resource pool tier if it can determine, for example, that it may not be able to find the channel clear for a certain number of opportunities in a first resource pool tier.

[0288] 4 is an example of resource pool tier selection and use. For example, if the WTRU may determine that it may not have found the channel clear for a certain number of opportunities in a first resource pool tier, the WTRU may attempt (e.g., decide to) use a second resource pool tier.

[0289] A switch to grant-based access may be provided. For example, if the WTRU may not be able to transmit on grant-free resources (e.g., Tier 1 and / or Tier 2) (e.g., due to a determination that the channel may be busy), the WTRU may request grant-based resources and / or licensed resources. For example, the WTRU may make a request if it is unable to transmit using grant-free resources for a threshold number of attempts. The number of attempts may include, for example, a number of Tier 1 attempts and / or a number of Tier 2 attempts.

[0290] The WTRU may request grant-based resources and / or licensed resources, for example, by transmitting (i) a scheduling request (SR) on a licensed channel (e.g., on a PCell), (ii) an SR on an unlicensed channel, and / or (iii) a PRACH on a licensed or unlicensed channel.

[0291] The SR may be transmitted on allocated resources (eg, resources allocated to the PUCCH channel).

[0292] Resource pooling may occur infrequently, for example, for some types of communications (e.g., MTC). In examples, resource pooling may occur several times per day. In examples, resource pooling may occur during a pattern of time periods that may occur one or more times per day.

[0293] For example, if the WTRU may not be able to use the grant-free resource after a certain number of attempts, the WTRU may use the PRACH resource, which may occur more (e.g., more) frequently.

[0294] 5 is an example of resource pool tier selection and use. For example, if the WTRU may determine that it may not be able to find the channel clear for a certain number of opportunities in a first resource pool tier, the WTRU may attempt (e.g., decide to) use a second resource pool tier. For example, if it may determine that it may not be able to find the channel clear for a certain number of opportunities in the second resource pool tier, the WTRU may request (e.g., decide to) resources that are permitted or licensed.

[0295] 6 is an example of resource pool tier selection and use. For example, if the WTRU may determine that it may not have found the channel clear for a certain number of opportunities in the first resource pool tier, the WTRU may attempt (e.g., decide to) use the second resource pool tier. For example, if it may determine that it may not have found the channel clear for a certain number of opportunities in the second resource pool tier, the WTRU may request (e.g., decide to) resources that are permitted or licensed.

[0296] Unlicensed operation may be provided in a beam-based system. Resource pools may be provided in a beam-based system. In an example, one or more resource pools may be used to support multiple beams. One (e.g., each) resource pool may be associated with a beam or beam pair link (BPL).

[0297] One (e.g., each) resource pool may be configured with an associated downlink signal that may be used, for example, to measure the quality of the beam. The measurement may be, for example, an RSRP measurement. Downlink signals that may be used for beam quality measurement may include, for example, a beam discovery signal, a beam reference signal, a CSI-RS, an SS burst (e.g., an SS in an SS burst), and / or an SS block (e.g., an SS in an SS block).

[0298] The resource pool for a beam or BPL may be configured in a periodic manner. In an example, the resource pool for a beam or BPL may be present, available, used, configured, or determined, for example, every T1 cycle or periodically with a time period of T1.

[0299] A WTRU may be configured with one or more beams or BPLs for grant-free access, and one or more resource pools for the one or more beams or BPLs may be arranged, for example, in orthogonal time resources.

[0300] One or more SS blocks may be used in an SS burst. (E.g., each) SS block may be associated with one beam. (E.g., each) resource pool that may be associated with one beam may be located in (e.g., the same) time resource with the SS block associated with that beam.

[0301] The WTRU may determine a resource pool that may be associated with the beam or beam pair link determined by the WTRU. In an example, the WTRU may measure the beam quality of the SS blocks in the SS burst. The WTRU may determine the best or preferred beam (e.g., SS block), for example, based on the beam quality measurement. Signaling (e.g., broadcast signaling) may provide the associated resource pool for one (e.g., each) beam. The WTRU may use the resource pool associated with the determined beam or BPL for grant-free access.

[0302] The WTRU may indicate or otherwise inform the gNB of the determined beam (e.g., SS block) for grant-free access. The gNB may check or configure a resource pool for use by the WTRU.

[0303] The gNB may provide, for example, a WTRU with a WTRU-ID (e.g., a C-RNTI) for use for grant-free access in a beam-specific resource pool.

[0304] The WTRU may attempt grant-free access in the resource pool. For example, if the WTRU may be unable to access a channel for a resource pool (e.g., for a predefined or configured number of times (e.g., N times)) or unable to successfully transmit using the resource pool, the WTRU may switch to another resource pool that may be associated with a different beam. The inability to successfully transmit may include, for example, being unable to receive an acknowledgement (e.g., HARQ-ACK), e.g., from the gNB, in response to a transmission.

[0305] CCA may be performed in a beam-based system. In an example, a WTRU may perform CCA with respect to one or more resource pools, which may be associated with one or more beams or BPLs (e.g., determined beams or BPLs). The WTRU may determine an Rx beam to use for purposes of performing CCA (e.g., if the WTRU is capable of performing CCA), e.g., based on an Rx beam that the WTRU may have used for beam determination.

[0306] The WTRU may perform CCA on the resource pool based on, for example, the Rx beams that may have been used when the WTRU determined the beam or BPL.

[0307] The WTRU may perform CCA with respect to the resource pool based on, for example, one (e.g., best) Rx beam that can provide the highest RSRP. The best Rx beam may correspond to a Tx beam that the WTRU can use to transmit using the resource pool.

[0308] The WTRU may perform CCA for one or more (e.g., all) Rx beams. The energy level that the WTRU may use to determine channel occupancy may be based, for example, on the highest energy measured or detected for one (e.g., any) Rx beam.

[0309] The WTRU may perform CCA on one or more (e.g., all) Rx beams. The energy level that the WTRU may use to determine channel occupancy may be based, for example, on an average of the energy levels of one or more (e.g., all) Rx beams. Rx beam sweeping may be performed within a CCA duration (e.g., 4 μs, 9 μs, or 25 μs). Rx beam sweeping may be performed over multiple CCA durations.

[0310] The WTRU may determine that the channel is clear, e.g., after beam sweeping. The WTRU may perform CCA (e.g., a short CCA, such as of 25 μs duration), e.g., using an Rx beam that may correspond to a Tx beam from which the WTRU may (e.g., will) transmit immediately before transmission, to ensure that the channel is likely (e.g., is) clear in that direction before transmission. The WTRU may transmit, e.g., if the WTRU may determine that the channel is clear. The WTRU may not transmit, e.g., if the WTRU may determine that the channel is not clear.

[0311] Systems, methods, and means have been disclosed for transmission adaptation and grant-free access in unlicensed bands. Flexible transmission boundaries can be provided for transmission adaptation. Grant-free access resource pools can be provided. Unlicensed operation can be provided in beam-based systems, for example, using resource pools and / or CCA.

[0312] Features, elements, and actions (e.g., processes and means) are described as non-limiting examples. While examples may be directed to LTE, LTE-A, New Radio (NR), or 5G protocols, the subject matter herein is applicable to other wireless communications, systems, services, and protocols. Each feature, element, action, or other aspect of the subject matter described, whether presented in the figures or in the description, can be implemented alone or with other subject matter, known or unknown, in any combination, including in any order, regardless of the examples presented herein.

[0313] The WTRU may refer to a physical device identity or a subscription-related identity, e.g., a user's identity such as MSISDN, SIP URI, etc. The WTRU may refer to an application-based identity, e.g., a username that may be used per application.

[0314] The processes described above may be implemented in a computer program, software, and / or firmware embodied in a computer-readable medium for execution by a computer and / or processor. Examples of computer-readable media include, but are not limited to, electronic signals (transmitted via wired and / or wireless connections) and / or computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, ROM, RAM, registers, cache memory, semiconductor memory devices, magnetic media such as, but not limited to, internal hard disks and removable disks, magneto-optical media, and / or optical media such as CD-ROM disks and / or DVDs. A processor associated with the software may be used to implement a radio frequency transceiver for use in a WTRU, a terminal, a base station, an RNC, and / or any host computer.

Claims

1. 1. A wireless transmit / receive unit (WTRU) comprising a processor and a memory, The processor and the memory receiving downlink control information (DCI), the DCI including an allocation for downlink transmission; generating first feedback associated with the downlink transmission; determining that a channel access attempt for a first transmission opportunity for transmitting the first feedback has failed; determining a second transmission opportunity for transmitting the first feedback; determining that second feedback associated with a second downlink transmission will be transmitted along with the first feedback at the second transmit opportunity; determining that a channel access attempt for the second transmission opportunity is successful; and transmitting an uplink transmission including the first feedback and the second feedback during the second transmission opportunity based on the channel access attempt being successful for the second transmission opportunity; a WTRU configured to:

2. The WTRU of claim 1 , wherein the first feedback comprises a hybrid automatic repeat request (HARQ) acknowledgement / negative acknowledgement (ACK / NACK).

3. 3. The WTRU of claim 2, wherein the first feedback further includes a channel quality indicator (CQI), and the processor and the memory are further configured to drop the CQI from the first feedback based on a determination that a channel access attempt for the first transmission opportunity failed.

4. 3. The WTRU of claim 2, wherein the first feedback further includes a CQI, and the processor and the memory are further configured to drop the CQI from the first feedback based on an amount of time available for transmission in the second transmission opportunity.

5. 3. The WTRU of claim 2, wherein the first feedback further includes a CQI, and the processor and the memory are further configured to drop the CQI from the first feedback based on when the channel access attempt for the second transmission opportunity is determined to be successful.

6. The WTRU of claim 1 , wherein the processor and the memory are further configured to receive the indication of the first transmission opportunity and the indication of the second transmission opportunity via a DCI.

7. 2. The WTRU of claim 1, wherein the uplink transmission is a physical uplink control channel (PUCCH) transmission.

8. The WTRU of claim 1 , wherein the uplink transmission is transmitted using resources associated with a candidate resource set.

9. 1. A method performed by a wireless transmit / receive unit (WTRU), the method comprising: receiving downlink control information (DCI), the DCI including an allocation for downlink transmission; generating first feedback associated with the downlink transmission; determining that a channel access attempt for a first transmission opportunity for transmitting the first feedback has failed; determining a second transmission opportunity for transmitting the first feedback; determining that second feedback associated with a second downlink transmission will be transmitted along with the first feedback at the second transmit opportunity; determining that a channel access attempt for the second transmission opportunity is successful; and transmitting an uplink transmission including the first feedback and the second feedback during the second transmission opportunity based on the channel access attempt being successful for the second transmission opportunity; A method comprising:

10. 10. The method of claim 9, wherein the first feedback comprises a hybrid automatic repeat request (HARQ) acknowledgement / negative acknowledgement (ACK / NACK).

11. 11. The method of claim 10, wherein the first feedback further includes a channel quality indicator (CQI), the method further including dropping the CQI from the first feedback based on a determination that a channel access attempt for the first transmission opportunity failed.

12. 11. The method of claim 10, wherein the first feedback further includes a CQI, the method further including dropping the CQI from the first feedback based on an amount of time available for transmission in the second transmission opportunity.

13. 11. The method of claim 10, wherein the first feedback further includes a CQI, and the method further includes dropping the CQI from the first feedback based on when the channel access attempt for the second transmission opportunity is determined to be successful.

14. 10. The method of claim 9, further comprising receiving the indication of the first transmission opportunity and the indication of the second transmission opportunity via a DCI.

15. 10. The method of claim 9, wherein the uplink transmission is a physical uplink control channel (PUCCH) transmission.

16. The method of claim 9 , wherein the uplink transmission is transmitted using resources associated with a candidate resource set.

Images