Short control signal transmission

Abstract

Systems, methods, and tools associated with short control signal transmissions are described herein. A wireless transmit / receive unit (WTRU) as described herein may receive configuration information from a network device, wherein the configuration information may indicate first short control signal transmission (SCSt) configuration information. The WTRU may determine whether a signal to be transmitted satisfies a condition, wherein the condition may be associated with at least a transmission priority associated with the signal. Based on determining that the signal satisfies the condition, the WTRU may transmit the signal based on the first SCSt configuration information indicated by the configuration information. The WTRU may select the first SCSt configuration information rather than the second SCSt configuration information also received by the WTRU. The WTRU may make a selection based on one or more characteristics of the signal to be transmitted.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of Provisional U.S. Patent No. 63 / 410,905, filed on September 28, 2022, the entire disclosure of which is incorporated herein by reference. Background Art

[0003] In wireless communications, a clear channel access (CCA) may be obtained to occupy a channel (e.g., in an unlicensed band) for transmission. A transmission may be performed without obtaining a CCA if the transmission meets certain requirements. However, the number and / or duration of such transmissions may be limited. Summary of the invention

[0004] Systems, methods, and tools associated with short control signal transmission are described herein. A wireless transmit / receive unit (WTRU) as described herein may receive configuration information from a network device, wherein the configuration information may indicate first short control signal transmission (SCSt) configuration information. The WTRU may determine whether a signal to be transmitted satisfies a condition, wherein the condition may be associated with at least a transmission priority associated with the signal. Based on determining that the signal satisfies the condition, the WTRU may transmit the signal based on the first SCSt configuration information indicated by the configuration information.

[0005] In an example, the conditions described herein may also be associated with a broadcast type associated with a signal, a resource pool congestion state associated with a signal, a channel occupancy time associated with a signal, or a packet delay budget associated with a signal. In an example, the first SCSt configuration information described herein may indicate one or more of a first duty cycle, a first transmission duration, or a first transmission resource that may be used to perform SCSt. In an example, the configuration information may also indicate a second SCSt configuration information, which may indicate one or more of a second duty cycle, a second transmission duration, or a second transmission resource, and the WTRU may select the first SCSt configuration information instead of the second SCSt configuration information for transmission of the signal. The WTRU may select the first SCSt configuration information instead of the second SCSt configuration information based on one or more of a broadcast type associated with a signal, a resource pool congestion state associated with a signal, a channel occupancy time associated with a signal, or a packet delay budget associated with a signal.

[0006] In an example, the WTRU may send a message to another WTRU indicating that a signal has been sent based on the first SCSt configuration information. In an example, if the signal meets the condition, the WTRU may send the signal through the channel without obtaining idle channel access to the channel, and if the signal does not meet the condition, the WTRU may obtain idle channel access to the channel and send the signal through the channel.

[0007] In an example, a signal sent using the first SCSt configuration may be associated with a physical sidelink feedback channel (PSFCH) transmission, a physical sidelink control channel (PSCCH) transmission, a sidelink synchronization signal block (S-SSB) transmission, or a sidelink channel state information (CSI) transmission. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1A is a system diagram illustrating an example communication system in which one or more disclosed embodiments may be implemented.

[0009] Figure 1B is a diagram showing that according to an embodiment, Figure 1A A system diagram of an example wireless transmit / receive unit (WTRU) for use within a communication system is shown in FIG.

[0010] Figure 1C is a diagram showing that according to an embodiment, Figure 1A A system diagram of an example radio access network (RAN) and an example core network (CN) for use within a communication system is shown in FIG.

[0011] Figure 1D is a diagram showing that according to an embodiment, Figure 1A A system diagram of another example RAN and another example CN used within a communication system shown in FIG.

[0012] Figure 2 is a diagram showing an example of grouping side link resources by the time difference between the side link resources and the SCSt resources.

[0013] Figure 3 is a diagram showing an example of a WTRU configured with multiple SCSt configurations.

[0014] Figure 4 is a flow chart illustrating example operations that may be performed by a WTRU for an SCSt. DETAILED DESCRIPTION

[0015] Figure 1A1 is a diagram illustrating an example communication system 100 in which one or more disclosed embodiments may be implemented. The communication system 100 may be a multiple access system that provides content such as voice, data, video, messaging, broadcast, etc. to multiple wireless users. The communication system 100 may enable multiple wireless users to access such content by sharing system resources, including wireless bandwidth. For example, the communication system 100 may use one or more channel access methods, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single carrier FDMA (SC-FDMA), zero tail unique word DFT-spread OFDM (ZT UW DTS-s OFDM), unique word OFDM (UW-OFDM), resource block filtered OFDM, filter bank multi-carrier (FBMC), etc.

[0016] like Figure 1A As shown, the communication system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, RAN 104 / 113, CN 106 / 115, public switched telephone network (PSTN) 108, Internet 110, and other networks 112, but it should be appreciated that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network elements. Each of the WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and / or communicate in a wireless environment. As an example, the WTRUs 102a, 102b, 102c, 102d (any of which may be referred to as a "station" and / or "STA") may be configured to send and / or receive wireless signals and may include a user equipment (WTRU), a mobile station, a fixed or mobile subscriber unit, a subscription-based unit, a pager, a cellular phone, a personal digital assistant (PDA), a smart phone, a laptop, a netbook, a personal computer, a wireless sensor, a hotspot or Mi-Fi device, an Internet of Things (IoT) device, a watch or other wearable device, a head-mounted display (HMD), a vehicle, a drone. Medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in an industrial and / or automated process chain environment), consumer electronic devices, devices operating on a commercial and / or industrial wireless network, etc. Any of the WTRUs 102a, 102b, 102c, and 102d may be interchangeably referred to as a WTRU.

[0017] The communication system 100 may also include a base station 114a and / or a base station 114b. Each of the base stations 114a, 114b may be any type of device configured to facilitate access to one or more communication networks (such as the CN 106 / 115, the Internet 110, and / or other networks 112) by wirelessly interfacing with at least one of the WTRUs 102a, 102b, 102c, 102d. By way of example, the base stations 114a, 114b may be base transceiver stations (BTS), node-Bs, eNodeBs (eNBs), home nodeBs, home eNodeBs, gNodeBs (base stations), NR NodeBs, site controllers, access points (APs), wireless routers, and the like. Although each base station 114a, 114b is depicted as a single element, it should be appreciated that the base stations 114a, 114b may include any number of interconnected base stations and / or network elements.

[0018] The base station 114a may be part of the RAN 104 / 113, which may also include other base stations and / or network elements (not shown), such as a base station controller (BSC), a radio network controller (RNC), a relay node, etc. The base station 114a and / or the base station 114b may be configured to send and / or receive wireless signals on one or more carrier frequencies, which may be referred to as a cell (not shown). These frequencies may be in a licensed spectrum, an unlicensed spectrum, or a combination of a licensed spectrum and an unlicensed spectrum. A cell may provide coverage for wireless services to a specific geographic area, which may be relatively fixed or may change over time. The cell may also be divided into cell sectors. For example, a 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, that is, each transceiver corresponds to a sector of the cell. In an embodiment, the base station 114a may use multiple-input multiple-output (MIMO) technology and may use multiple transceivers for each sector of the cell. For example, beamforming may be used to send and / or receive signals in a desired spatial direction.

[0019] The base stations 114a, 114b may communicate with one or more of the WTRUs 102a, 102b, 102c, 102d over an air interface 116, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet (UV), visible light, etc.). The air interface 116 may be established using any suitable radio access technology (RAT).

[0020] More specifically, as described above, the communication system 100 may be a multiple access system and may use one or more channel access schemes such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, etc. For example, the base station 114a in the RAN 104 / 113 and the WTRUs 102a, 102b, 102c may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may use Wideband CDMA (WCDMA) to establish the air interface 115 / 116 / 117. WCDMA may include communication protocols such as High Speed ​​Packet Access (HSPA) and / or Evolved HSPA (HSPA+). HSPA may include High Speed ​​Downlink (DL) Packet Access (HSDPA) and / or High Speed ​​UL Packet Access (HSUPA).

[0021] 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).

[0022] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as NR radio access, which may establish the air interface 116 using New Radio (NR).

[0023] 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 LTE radio access and NR radio access together, for example using the dual connectivity (DC) principle. Thus, the air interface used 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 base stations).

[0024] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement radio technologies such as IEEE 802.11 (i.e., Wireless Fidelity (WiFi)), IEEE 802.16 (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), GSM Enhanced Data rates for Evolution (EDGE), GSM EDGE (GERAN), etc.

[0025] Figure 1A The base station 114b in may be a wireless router, a Home NodeB, a Home eNodeB, or an access point, for example, and may utilize any appropriate RAT to facilitate wireless connectivity in a local area, such as a business location, a home, a vehicle, a campus, an industrial facility, an air corridor (e.g., for use by drones), a road, and the like. 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. Figure 1A As shown, the base station 114b may have a direct connection to the Internet 110. Thus, the base station 114b may not be required to access the Internet 110 via the CN 106 / 115.

[0026] 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 Voice over Internet Protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. Data may have varying quality of service (QoS) requirements, such as different throughput requirements, latency requirements, fault tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, etc. The CN 106 / 115 may provide call control, billing services, mobile location-based services, prepaid calling, Internet connectivity, video distribution, etc., and / or perform advanced security functions (such as user authentication). Although in Figure 1AAlthough not shown, it will be appreciated that the RAN 104 / 113 and / or the CN 106 / 115 may be in direct or indirect communication with other RANs that employ the same RAT or a different RAT as the RAN 104 / 113. For example, in addition to being connected to the RAN 104 / 113, which may employ NR radio technology, the CN 106 / 115 may also be in communication with another RAN (not shown) employing GSM, UMTS, CDMA 2000, WiMAX, E-UTRA, or WiFi radio technology.

[0027] 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 that provides 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 the Transmission Control Protocol (TCP), the User Datagram Protocol (UDP), and / or the Internet Protocol (IP) in the TCP / IP Internet protocol suite. The networks 112 may include wired and / or wireless communication networks owned and / or operated by other service providers. For example, the networks 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.

[0028] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communication system 100 may include multi-mode capabilities (e.g., the WTRUs 102a, 102b, 102c, 102d may include multiple transceivers for communicating with different wireless networks over different wireless links). Figure 1A The illustrated WTRU 102c may be configured to communicate with the base station 114a, which may employ a cellular-based radio technology, and with the base station 114b, which may employ an IEEE 802 radio technology.

[0029] Figure 1B is a system diagram illustrating an example WTRU 102. Figure 1B As shown, the WTRU 102 may include, among other things, a processor 118, a transceiver 120, a transmit / receive element 122, a speaker / microphone 124, a keyboard 126, a display / touchpad 128, non-removable memory 130, removable memory 132, a power source 134, a global positioning system (GPS) chipset 136, and / or other peripherals 138. It will be appreciated that the WTRU 102 may include any sub-combination of the foregoing elements while remaining consistent with an embodiment.

[0030] The processor 118 may be a general purpose processor, a special purpose processor, a conventional processor, a digital signal processor (DSP), a plurality of microprocessors, one or more microprocessors associated with a DSP core, a controller, a microcontroller, an application specific integrated circuit (ASIC) field programmable gate array (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. Although Figure 1B The processor 118 and the transceiver 120 are depicted as separate components, but it will be appreciated that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip.

[0031] The transmit / receive element 122 may be configured to send or receive signals to or from a base station (e.g., base station 114a) via an air interface 116. For example, in one embodiment, the transmit / receive element 122 may be an antenna configured to send and / or receive RF signals. In an embodiment, the transmit / receive element 122 may be, for example, a transmitter / detector configured to send and / or receive IR, UV, or visible light signals. In yet another embodiment, the transmit / receive element 122 may be configured to send and / or receive both RF and optical signals. It should be understood that the transmit / receive element 122 may be configured to send and / or receive any combination of wireless signals.

[0032] Although the transmit / receive element 122 is Figure 1B Although depicted as a single element in the figure, 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.

[0033] 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 described 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 (e.g., NR and IEEE 802.11).

[0034] The processor 118 of the WTRU 102 may be coupled to a speaker / microphone 124, a keyboard 126, and / or a display / touchpad 128 (e.g., a liquid crystal display (LCD) display unit or an organic light emitting diode (OLED) display unit), and may receive user input data from these components. The processor 118 may also output user data to the speaker / microphone 124, the keyboard 126, and / or the display / touchpad 128. In addition, the processor 118 may access information from and store data in any type of suitable memory, such as a non-removable memory 130 and / or a removable memory 132. The non-removable memory 130 may include a random access memory (RAM), a read-only memory (ROM), a hard disk, or any other type of memory storage device. The removable memory 132 may include a subscriber identity module (SIM) card, a memory stick, a secure digital (SD) memory card, and the like. In other embodiments, the processor 118 may access information from and store data in memories that are not physically located on the WTRU 102, such as on a server or a home computer (not shown).

[0035] The processor 118 may receive power from the power source 134, and may be configured to distribute and / or control power for use by the other components in the WTRU 102. The power source 134 may be any suitable device for powering the WTRU 102. For example, the power source 134 may include one or more dry cell batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel-metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, etc.

[0036] The processor 118 may also be coupled to the GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) regarding the current location of the WTRU 102. In addition to or in lieu of the information from the GPS chipset 136, the WTRU 102 may receive location information from a base station (e.g., base stations 114a, 114b) over the air interface 116 and / or determine its location based on the timing of signals received from two or more nearby base stations. It will be appreciated that the WTRU 102 may acquire location information via any suitable location-determination method while remaining consistent with an embodiment.

[0037] The processor 118 may also be coupled to other peripherals 138, which may include one or more software and / or hardware modules that provide additional features, functionality, and / or wired or wireless connectivity. For example, the peripherals 138 may include an accelerometer, an electronic compass, a satellite transceiver, a digital camera (for photos and / or videos), a universal serial bus (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 console module, an Internet browser, a virtual reality and / or augmented reality (VR / AR) device, an activity tracker, etc. The peripherals 138 may include one or more sensors, which may be one or more of a gyroscope, an accelerometer, a Hall effect sensor, a magnetometer, an orientation sensor, a proximity sensor, a temperature sensor, a time sensor; a geolocation sensor; an altimeter, a light sensor, a touch sensor, a magnetometer, a barometer, a gesture sensor, a biometric sensor, and / or a humidity sensor.

[0038] The WTRU 102 may include a full-duplex radio for which transmission and reception of some or all of the signals (e.g., associated with specific subframes for both UL (e.g., for transmission) and downlink (e.g., for reception)) may be concurrent and / or simultaneous. The full-duplex radio may include an interference management unit to reduce and / or substantially eliminate self-interference via hardware (e.g., choke) or via signal processing by a processor (e.g., a separate processor (not shown) or via the processor 118). In an embodiment, the WRTU 102 may include a half-duplex radio for which transmission and reception of some or all of the signals (e.g., associated with specific subframes for both UL (e.g., for transmission) or downlink (e.g., for reception)) may be concurrent and / or simultaneous.

[0039] Figure 1C 1 is a system diagram showing the RAN 104 and the CN 106 according to an embodiment. As described above, the RAN 104 may employ an 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.

[0040] The RAN 104 may include eNode-Bs 160a, 160b, 160c, though it will be appreciated that the RAN 104 may include any number of eNode-Bs while remaining consistent with an embodiment. The eNode-Bs 160a, 160b, 160c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In one embodiment, the eNode-Bs 160a, 160b, 160c may implement MIMO technology. Thus, for example, the eNode-B 160a may use multiple antennas to transmit wireless signals to and / or receive wireless signals from the WTRU 102a.

[0041] Each of the eNodeBs 160a, 160b, 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, user scheduling in UL and / or DL, etc. Figure 1C As shown, the eNode-Bs 160a, 160b, 160c may communicate with one another via an X2 interface.

[0042] Figure 1C The illustrated CN 106 may include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (or PGW) 166. While each of the foregoing elements is depicted as part of the CN 106, it should be appreciated that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0043] 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 serve as a control node. For example, the MME 162 may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, bearer activation / deactivation, selecting a particular serving gateway during an initial attach of the WTRUs 102a, 102b, 102c, and the like. The MME 162 may provide a control plane function for switching between the RAN 104 and other RANs (not shown) that employ other radio technologies, such as GSM and / or WCDMA.

[0044] 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 anchoring the user plane during inter-eNode-B handover, triggering paging when DL data is available for the WTRUs 102a, 102b, 102c, managing and storing the context of the WTRUs 102a, 102b, 102c, and the like.

[0045] The SGW 164 may be connected to the PGW 166, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices.

[0046] The CN 106 may facilitate communications with other networks. For example, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to circuit-switched networks, such as the PSTN 108, to facilitate communications between the WTRUs 102a, 102b, 102c and traditional land-line communications 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. In addition, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired and / or wireless networks owned and / or operated by other service providers.

[0047] Although the WTRU Figure 1A-Figure 1D Although described as a wireless terminal, it is contemplated that in certain representative embodiments such a terminal may use a wired communication interface (eg, temporarily or permanently) with a communication network.

[0048] In a representative embodiment, other network 112 may be a WLAN.

[0049] A WLAN in infrastructure basic service set (BSS) mode may have an access point (AP) for the BSS and one or more stations (STAs) associated with the AP. The AP may have access or an interface to a distribution system (DS) or another type of wired / wireless network that carries traffic into and / or out of the BSS. Traffic originating from outside the BSS to a STA may arrive through the AP and may be delivered to the STA. Traffic originating from a STA to a destination outside the BSS may be sent to the AP to be delivered to the corresponding destination. Traffic between STAs within the BSS may be sent through the AP, for example, where the source STA may send traffic to the AP, and the AP may deliver the traffic to the destination STA. Traffic between STAs within the BSS may be considered and / or referred to as peer-to-peer traffic. Peer-to-peer traffic may be sent between a source STA and a destination STA (e.g., directly between the source STA and the destination STA) using a direct link setup (DLS). In certain representative embodiments, the DLS may use 802.11e DLS or 802.11z tunnel DLS (TDLS). A WLAN using an independent BSS (IBSS) mode may not have an AP, and STAs (eg, all STAs) within or using the IBSS may communicate directly with each other. The IBSS mode of communication may sometimes be referred to herein as an "ad-hoc" communication mode.

[0050] When using the 802.11 ac infrastructure mode of operation or a similar mode of operation, the AP may send beacons on a fixed channel, such as a primary channel. The primary channel may be a fixed width (e.g., a 20 MHz wide bandwidth) or a width dynamically set via signaling. The primary channel may be an operating channel of the BSS and may be used by STAs to establish a connection with the AP. In certain representative embodiments, carrier sense multiple access with collision avoidance (CSMA / CA) may be implemented, such as in an 802.11 system. For CSMA / CA, a STA (e.g., each STA), including the AP, may sense the primary channel. If the primary channel is sensed / detected and / or determined to be busy by a particular STA, the particular STA may back off. One STA (e.g., only one station) may transmit at any given time in a given BSS.

[0051] A high throughput (HT) STA may communicate using a 40 MHz wide channel formed by combining a 20 MHz wide primary channel with an adjacent or non-adjacent 20 MHz wide channel.

[0052] Very High Throughput (VHT) STA can support 20 MHz, 40 MHz, 80 MHz and / or 160 MHz wide channels. 40 MHz and / or 80 MHz channels can be formed by combining consecutive 20 MHz channels. A 160 MHz channel can be formed by combining 8 consecutive 20 MHz channels or by combining two non-contiguous 80 MHz channels, which can be referred to as an 80+80 configuration. For the 80+80 configuration, the data after channel coding can pass through a segment parser, which can divide the data into two streams. Inverse Fast Fourier Transform (IFFT) processing and time domain processing can be performed separately on each stream. The stream can be mapped onto two 80 MHz channels, and the data can be sent by the transmitting STA. At the receiver of the receiving STA, the above operations for the 80+80 configuration can be reversed, and the combined data can be sent to the medium access control (MAC).

[0053] Sub-1 GHz operating modes are supported by 802.11af and 802.11ah. The channel operating bandwidth and carriers in 802.11af and 802.11ah are reduced relative to the channel operating bandwidth and carriers used in 802.11n and 802.11ac. 802.11af supports 5 MHz, 10 MHz, and 20 MHz bandwidths in the TV White Space (TVWS) spectrum, and 802.11ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths using non-TVWS spectrum. According to a representative embodiment, 802.11ah may support meter type control / machine type communications, such as MTC devices in macro coverage areas. MTC devices may have certain capabilities, such as limited capabilities including support for (e.g., only support for) certain and / or limited bandwidths. MTC devices may include batteries with battery life above a threshold (e.g., to maintain very long battery life).

[0054] WLAN systems that can support multiple channels and channel bandwidths (such as 802.11n, 802.11ac, 802.11af, and 802.11ah) include channels that can be designated as primary channels. The primary channel may have a bandwidth equal to the maximum common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel may be set and / or limited by a STA from all STAs operating in the BSS that support the minimum bandwidth operating mode. In the example of 802.11ah, for STAs (e.g., MTC type devices) that support (e.g., only support) 1MHz 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) settings may depend on the state of the primary channel. If the primary channel is busy, for example, because a STA (which only supports 1 MHz operating mode) sends to the AP, the entire available band may be considered busy even if most of the band remains idle and can be available.

[0055] In the United States, the available frequency band that 802.11ah can use is from 902MHz to 928MHz. 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. Depending on the country code, the total bandwidth available for 802.11ah is 6 MHz to 26 MHz.

[0056] Figure 1D 1 is a system diagram showing 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.

[0057] The RAN 113 may include base stations 180a, 180b, 180c, but it should be appreciated that the RAN 113 may include any number of base stations while remaining consistent with the embodiment. The base stations 180a, 180b, 180c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In one embodiment, the base stations 180a, 180b, 180c may implement MIMO technology. For example, the base stations 180a, 108b may utilize beamforming to send signals to and / or receive signals from the base stations 180a, 180b, 180c. Therefore, the base station 180a may, for example, use multiple antennas to send wireless signals to and / or receive wireless signals from the WTRU 102a. In an embodiment, the base stations 180a, 180b, 180c may implement carrier aggregation technology. For example, the base station 180a may send multiple component carriers (not shown) to the WTRU 102a. 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 base stations 180a, 180b, 180c may implement coordinated multi-point (CoMP) technology. For example, the WTRU 102a may receive coordinated transmissions from the base station 180a and the base station 180b (and / or the base station 180c).

[0058] The WTRUs 102a, 102b, 102c may communicate with the base stations 180a, 180b, 180c using transmissions associated with scalable numerologies. For example, OFDM symbol spacing and / or OFDM subcarrier spacing may vary for different transmissions, different cells, and / or different portions of the wireless transmission spectrum. The WTRUs 102a, 102b, 102c may communicate with the base stations 180a, 180b, 180c using subframes or transmission time intervals (TTIs) of varying or scalable lengths (e.g., containing varying numbers of OFDM symbols and / or varying absolute time lengths over time).

[0059] The base stations 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 base stations 180a, 180b, 180c without accessing other RANs (e.g., such as the eNode-Bs 160a, 160b, 160c). In a standalone configuration, the WTRUs 102a, 102b, 102c may utilize one or more of the base stations 180a, 180b, 180c as mobility anchors. In a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the base stations 180a, 180b, 180c using signals in an unlicensed band. In a non-standalone configuration, the WTRUs 102a, 102b, 102c may communicate / connect with the base stations 180a, 180b, 180c while also communicating / connecting with another RAN, such as the eNode-Bs 160a, 160b, 160c. For example, the WTRUs 102a, 102b, 102c may implement DC principles to communicate with one or more base stations 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 serve as mobility anchors for the WTRUs 102a, 102b, 102c, and the base stations 180a, 180b, 180c may provide additional coverage and / or throughput for serving the WTRUs 102a, 102b, 102c.

[0060] Each of the base stations 180a, 180b, 180c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, user scheduling in UL and / or DL, support network slicing, dual connectivity, interworking between NR and E-UTRA, routing of user plane data to a user plane function (UPF) 184a, 184b, routing of control plane information to an access and mobility management function (AMF) 182a, 182b, and the like. Figure 1D As shown, base stations 180a, 180b, 180c may communicate with each other via an Xn interface.

[0061] Figure 1D The illustrated CN 115 may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one session management function (SMF) 183a, 183b, and may include a data network (DN) 185a, 185b. Although each of the foregoing elements is depicted as part of the CN 115, it should be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0062] The AMF 182a, 182b may be connected to one or more of the base stations 180a, 180b, 180c in the RAN 113 via an N2 interface and may serve as a control node. For example, the AMF 182a, 182b may be responsible for authenticating users of the WTRU 102a, 102b, 102c, supporting network slicing (e.g., handling different PDU sessions with different requirements), selecting a specific SMF 183a, 183b, managing registration areas, termination of NAS signaling, mobility management, etc. The AMF 182a, 182b may use network slicing to customize CN support for the WTRU 102a, 102b, 102c based on the type of service utilized by the WTRU 102a, 102b, 102c. For example, different network slices may be established for different use cases, such as services relying on ultra-reliable low latency (URLLC) access, services relying on enhanced massive mobile broadband (eMBB) access, services for machine type communication (MTC) access, etc. The AMF 162 may provide a control plane function for switching between the RAN 113 and other RANs (not shown) that employ other radio technologies, such as LTE, LTE-A, LTE-APro, and / or non-3GPP access technologies such as WiFi.

[0063] The SMF 183a, 183b may be connected to the AMF 182a, 182b in the CN 115 via the N11 interface. The SMF 183a, 183b may also be connected to the UPF 184a, 184b in the CN 115 via the N4 interface. The SMF 183a, 183b may select and control the UPF 184a, 184b, and configure the routing of traffic through the UPF 184a, 184b. The SMF 183a, 183b may perform other functions such as managing and allocating WTRU IP addresses, managing PDU sessions, controlling policy enforcement and QoS, and providing downlink data notifications, etc. The PDU session type may be IP-based, non-IP-based, Ethernet-based, etc.

[0064] The UPF 184a, 184b may be connected to one or more of the base stations 180a, 180b, 180c in the RAN 113 via an N3 interface, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices. The UPF 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.).

[0065] The CN 115 may facilitate communications with other networks. For example, the CN 115 may include or may communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that serves as an interface between the CN 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 a local data network (DN) 185a, 185b through the UPF 184a, 184b via an N3 interface to the UPF 184a, 184b and an N6 interface between the UPF 184a, 184b and the DN 185a, 185b.

[0066] Given that Figure 1A-Figure 1D and about Figure 1A-Figure 1D Corresponding to the description herein, one or more or all of the functions described herein with respect to one or more of the WTRU 102a-d, base station 114a-b, eNodeB 160a-c, MME 162, SGW 164, PGW 166, base station 180a-c, AMF 182a-b, UPF 184a-b, SMF 183a-b, DN 185a-b, and / or any other device(s) described herein may be performed by one or more emulation devices (not shown). An emulation device may be one or more devices configured to emulate one or more or all of the functions described herein. For example, an emulation device may be used to test other devices and / or simulate network and / or WTRU functions.

[0067] The simulation device can be designed to implement one or more tests of other devices in a laboratory environment and / or an operator network environment. For example, one or more simulation devices can perform one or more or all functions while being fully or partially implemented and / or deployed as part of a wired and / or wireless communication network in order to test other devices within the communication network. One or more simulation devices can perform one or more or all functions while being temporarily implemented / deployed as part of a wired and / or wireless communication network. The simulation device can be directly coupled to another device for the purpose of testing, and / or can use over-the-air wireless communication to perform testing.

[0068] One or more emulated devices can perform one or more, including all, functions while not being implemented / deployed as part of a wired and / or wireless communication network. For example, the emulated device can be used in a test lab and / or in a test scenario in a non-deployed (e.g., testing) wired and / or wireless communication network to implement testing of one or more components. One or more emulated devices can be test devices. The emulated device can send and / or receive data using direct RF coupling and / or wireless communication via RF circuitry (e.g., which can include one or more antennas).

[0069] In wireless communications (such as communications in an unlicensed spectrum), a clear channel access (CCA) may be performed to occupy a channel for transmission. If the transmission meets one or more conditions, the transmission may be performed as a short control signaling transmission (SCSt) without the need to obtain a CCA. The number of short control signaling transmissions (e.g., in the 5 GHz band) performed by a communication device (such as a WTRU) within an observation period (e.g., 50 ms) may be limited (e.g., not exceeding 50). The total duration of short control signal transmissions within the observation period may also be limited (e.g., not exceeding 2500 μs). Transmissions that may be performed as SCSt may include control signal transmissions (such as sidelink control signal transmissions, synchronization signal transmissions, etc.). In an example, SCSt may be performed without sensing or determining whether a channel is available. In an example, SCST may be performed after sensing the channel for a duration (e.g., a fixed duration).

[0070] Short control signaling may be supported in a wireless communication system such as a new radio (NR) system operating in an unlicensed spectrum. A discovery burst transmission (e.g., a synchronization signal block (SSB)) may satisfy a condition associated with an SCSt. Type 2A listen-before-talk (LBT) may be employed, for example, for a discovery reference signal (DRS) transmission in a shared spectrum, where one or more type 2A channel access procedures may be applicable (e.g., only applicable) to subsequent transmissions performed by a network device (e.g., a base station such as an eNB or gNB). These transmissions may include discovery bursts (e.g., excluding PDSCH transmissions, where the transmission duration is equal to or less than 1 ms). These transmissions may also include discovery bursts or discovery bursts multiplexed with non-unicast information, where the transmission duration is equal to or less than 1 ms and / or the discovery burst duty cycle is equal to or less than 1 / 2. The transmission may also include a transmission by a base station (e.g., an eNB and / or a gNB) that may follow a transmission by a WTRU in shared channel occupancy (e.g., after a gap of 25 μs). Wireless communications may be performed using unlicensed spectrum (e.g., above 52 GHz). The network equipment (e.g., a base station such as a gNB) and the WTRU may send discovery bursts and / or physical random access channel (PRACH) messages, respectively, during the random access procedure.

[0071] As described herein, SCSt may be sent without performing LBT or CCA. However, in some cases, it may not be possible to send a signal (e.g., a control signal) as SCSt. For example, a transmitter may be configured to comply with regulations and not send control signals that exceed limits as SCSts. Since the number of control signal transmissions may be greater than the number of transmissions allowed in a time period or duty cycle, the transmitter may not send additional control signals as SCST. In an example, a WTRU or network device may be configured to (e.g., dynamically) switch between using SCSt (e.g., without applying LBT prior to transmission) and using conventional LBT when performing control signal transmissions. A WTRU participating in sidelink communications (e.g., using unlicensed spectrum or frequency bands) may be configured to send SCSt in a manner that complies with regulatory requirements (e.g., without overuse).

[0072] SCSt may be used to perform physical sidelink feedback channel (PSFCH) transmission, physical sidelink control channel (PSCCH) transmission, sidelink synchronization signal block SSB (S-SSB) transmission, sidelink channel state information (CSI) related transmission, or other types of sidelink transmission (e.g., in unlicensed spectrum). The WTRU may be configured to perform any transmission that may qualify as a SCSt (e.g., satisfying conditions associated with the SCSt). For example, the WTRU may receive configuration information about conditions for determining whether a signal (e.g., a PSFCH and / or PSSCH transmission) is eligible as a SCSt (e.g., whether a PSFCH and / or PSSCH transmission can be sent as a SCSt). The WTRU may receive configuration information about conditions (e.g., including one or more rules) as part of RRC configuration information or as part of dynamic configuration information (e.g., via MAC CE or DCI). The WTRU may also be pre-configured with rules for determining whether a signal satisfies the conditions for SCSt transmission (e.g., based on standard specifications, the rules may be fixed for the WTRU).

[0073] The WTRU may be configured with a time period and / or a maximum number of transmissions that the WTRU may perform within the time period (e.g., the WTRU may be configured not to exceed the maximum number of transmissions within the time period). The WTRU may start sending SCSt within the configured time period and may start a timer (e.g., simultaneously with or immediately after the SCSt transmission). The duration of the timer may correspond to the configured time period. Before the timer expires, if the maximum number of transmissions has been reached, the WTRU may not be allowed to send SCSt. If the configured maximum number of transmissions is greater than 1 within the configured time period, the WTRU may (e.g., jointly) use a counter and a timer. The WTRU may send more than one transmission and may increase the counter after (e.g., each) transmission. When the counter value reaches the maximum number of transmissions within the configured time period, the WTRU may suppress sending SCSt until the timer expires.

[0074] The WTRU may receive SCSt configuration information that may indicate one or more of the following. The SCSt configuration information may indicate a period or time period during which the number of SCSt transmissions may be kept below a threshold. The SCSt configuration information may indicate a duty cycle associated with the maximum number of transmissions allowed within the configured period or time period. For example, a duty cycle of 3 may indicate that the WTRU may not send more than three SCSts within the configured period or period. The SCSt configuration information may indicate the maximum transmission duration of the transmission allowed in the duty cycle. For example, the WTRU may be configured with a maximum transmission duration of 1 ms for one or more transmissions within the duty cycle (e.g., for each allowed transmission). The SCSt configuration information may indicate a resource configuration associated with the SCSt transmission. For example, the WTRU may be configured with a resource pool and / or resource set that may be used for SCSt transmission, and the WTRU may use resources in the resource pool / resource set for SCSt transmission (e.g., when the WTRU is allowed to perform SCSt transmission). The resource configuration may indicate multiple transmission opportunities for short control signaling within the duty cycle, and the WTRU may use one of the opportunities within the duty cycle (e.g., at most one). In an example, the SCSt configuration information may not include a resource configuration, and it may be selected by the WTRU for the resources that may correspond to the SCSt transmission of the SCSt configuration information. The SCSt configuration information may indicate a channel access type and / or an LBT type. For example, the SCSt configuration information may include an indication of the type of LBT that the WTRU may perform before sending the SCSt. For example, the first SCSt configuration may indicate that LBT is not required before sending the SCSt corresponding to the first SCSt configuration, and the second SCSt configuration may indicate that LBT type 2A may be performed before sending the SCSt corresponding to the second SCSt configuration. The first SCSt configuration and the second SCSt configuration (e.g., having different LBT requirements) may include different SCSt resource configurations.

[0075] The SCSt configuration information received by the WTRU may indicate a priority associated with the SCSt configuration. The WTRU may use the priority to select the SCSt configuration for SCSt transmission. The SCSt configuration information may indicate the type of broadcast (e.g., broadcast, multicast, etc.) of the SCSt to be sent based on the SCSt configuration information. The SCSt configuration information may indicate the multiplexing configuration of the SCSt to be sent based on the SCSt configuration information. For example, the SCSt configuration information may indicate whether the SCSt transmission can be multiplexed with other transmissions. The multiplexing configuration may indicate which type can be multiplexed with the SCSt. For example, the SCSt configuration information may indicate that the SCSt can be multiplexed with unicast transmissions. In another example, the SCSt configuration information may indicate that the SCSt can be multiplexed with broadcast transmissions (e.g., only). The SCSt configuration information may indicate a cyclic prefix extension (CPE) configuration, which may indicate the length of the CPE (e.g., in the case where the WTRU can use the CPE before sending the SCSt). Multiple CPE lengths may be configured for the WTRU for (e.g., each) subcarrier spacing.

[0076] The WTRU may be configured with multiple SCSt configurations and may select one of the configurations to send a signal (e.g., a control signal). For example, the WTRU may receive configuration information that may indicate first SCSt configuration information (e.g., one or more of a first duty cycle, a first transmission duration, or a first transmission resource associated with the SCSt). The configuration information may also indicate second SCSt configuration information (e.g., one or more of a second duty cycle, a second transmission duration, or a second transmission resource associated with the SCSt). If the WTRU determines to send a signal (e.g., a control signal) as an SCSt, the WTRU may determine which SCSt configuration information is used for the SCSt. For example, the WTRU may select the first SCSt configuration information instead of the second SCSt configuration for the SCSt. The WTRU may make a selection based on various characteristics of the signal to be sent, such as, for example, the broadcast type of the signal, the congestion status of the resource pool associated with the signal, the channel occupancy time associated with the signal, and / or the packet delay budget associated with the signal.

[0077] After the WTRU selects an SCSt configuration, the WTRU may be configured not to use another (e.g., any other) SCSt configuration for a certain duration. For example, once the WTRU decides to use the first SCSt configuration, the WTRU may start a timer and wait until the timer expires before transmitting using another (e.g., any other) SCSt configuration (e.g., including the first SCSt configuration).

[0078] The WTRU may receive an SCSt configuration that may not include resource configuration information. The WTRU may use timers and / or counters to comply with the SCSt configuration. For example, if the WTRU performs transmissions based on a certain SCSt configuration, the WTRU may use timers and / or counters to ensure that the WTRU does not send more than the allowed number of transmissions within the duty cycle associated with the SCSt configuration.

[0079] The WTRU may receive a WTRU-specific SCSt configuration and / or a group-specific SCSt configuration. If the WTRU receives a group-specific SCSt configuration, the WTRU may be configured to share SCSt usage with a group of WTRUs, for example, to avoid exceeding a limit associated with the SCSt configuration (e.g., a maximum number of transmissions per time period or duty cycle).

[0080] The WTRU may select an SCSt configuration for a control signal transmission. For example, the WTRU may determine whether a control signal transmission qualifies as an SCSt transmission (e.g., satisfies conditions associated with SCSt transmission), and may select an SCSt configuration for sending the control signal. The control signal may be sent multiplexed with a non-control signal (e.g., a data signal) or may be sent without multiplexing with a non-control signal. For example, the WTRU may send a PSCCH (e.g., a sidelink control transmission) multiplexed with a PSSCH (e.g., a sidelink data transmission), or the WTRU may send an SL-SSB multiplexed with a PSSCH transmission. The WTRU may determine whether a control signal transmission qualifies as an SCSt based on one or more of the following conditions. If the transmission duration is less than a configured threshold, the WTRU may determine that the control signal transmission qualifies as an SCSt. For example, if the duration of the PSFCH transmission is less than a specific number of symbols (e.g., two), the PSFCH transmission may qualify as an SCSt transmission. The WTRU may determine that a control signal transmission qualifies as an SCSt based on the type of transmission associated with the control signal. For example, a PSSCH used for scheduling broadcast transmissions may qualify as an SCSt. The WTRU may determine that a control signal transmission qualifies as a SCSt based on a priority (e.g., on a per-packet priority basis) associated with the control signal transmission. For example, a control signal carrying high priority information (e.g., scheduling information) may qualify as a SCSt. The WTRU may determine that a control signal transmission qualifies as a SCSt based on the information carried by the control signal transmission. For example, a control signal carrying a preemption indication may qualify as a SCSt. The WTRU may determine that a control signal transmission qualifies as a SCSt based on a packet delay budget (PDB) associated with the control signal transmission.

[0081] The WTRU may determine (e.g., as a first step) whether a control signal qualifies as a SCSt and may select (e.g., as a second step) an SCSt configuration to apply to the control signal transmission. The selection may be conditional on one or more of the following. For example, a transmitter (Tx) WTRU may determine whether a control signal transmission qualifies as a SCSt transmission (e.g., based on the above conditions) and may indicate to a receiver (Rx) WTRU whether the control signal transmission qualifies as a SCSt transmission. The Tx WTRU may indicate to the Rx WTRU the SCSt configuration(s) from which the Rx WTRU may select and / or the SCSt transmission opportunities (e.g., SCSt resources) that the Rx WTRU may use. The Tx WTRU may use a bit field in the sidelink control information (SCI) to provide the Rx WTRU with the SCSt configuration(s) and / or the SCSt transmission resources(s).

[0082] The WTRU may select an SCSt configuration for control signal transmission based on one or more of the following (e.g., if the WTRU determines that the control signal transmission qualifies as an SCSt). The WTRU may select an SCSt configuration for control signal transmission based on a broadcast type associated with the control signal transmission. For example, if the WTRU is to send a control signal associated with a broadcast transmission, the WTRU may select an SCSt configuration associated with a broadcast transmission. The WTRU may select an SCSt configuration for control signal transmission based on a priority associated with the control signal transmission. For example, if the WTRU is to send a high priority control signal (e.g., carrying scheduling information), the WTRU may select an SCSt configuration associated with a high priority transmission. The WTRU may select an SCSt configuration for control signal transmission based on a resource pool congestion state / condition (e.g., which may be determined based on a channel busy ratio (CBR) measurement). For example, the WTRU may select an SCSt configuration for control signal transmission having a resource configuration associated with a less congested resource pool. For example, the WTRU may measure the CBR of one or more resource pools (e.g., of each resource pool) and may select a resource pool with a small CBR. The WTRU may select an SCSt configuration for control signal transmission based on the ongoing channel occupancy time (COT) and / or the initiation of the COT. If the WTRU has already initiated a COT or may initiate a COT in the next X ms (e.g., the value of X may depend on the PDB of (one or more) data transmissions associated with the control signal), the WTRU may determine not to use the SCSt configuration for control signal transmission. The WTRU may select an SCSt configuration for control signal transmission based on the availability of SCSt resources and / or PDBs (e.g., in terms of time). For example, the WTRU may select an SCSt configuration with SCSt resource availability that satisfies the PDB for (one or more) related transmissions. The WTRU may select an SCSt configuration for control signal transmission based on whether another transmission is to be multiplexed with the control signal transmission. For example, if the WTRU is to multiplex a unicast transmission with a control signal, the WTRU may select an SCSt configuration under which multiplexing with unicast may be allowed. If multiple SCSt configurations (e.g., multiple qualified configurations) may be used for control signal transmission, the WTRU may randomly select an SCSt configuration from the qualified configurations.

[0083] An SCSt transmission may be performed before an SCSt resource configuration is received. For example, the WTRU may be configured to perform a transmission before the next transmission opportunity performed by the SCSt configuration if waiting until the next opportunity may not satisfy the PDB for the associated sidelink data transmission. For example, the WTRU may determine that a PSFCH transmission qualifies as an SCSt and may select an SCSt transmission configuration for the PSFCH transmission. The first available SCSt resource within the selected SCSt transmission configuration may cause the WTRU to exceed the PDB associated with the data transmission related to the PSFCH transmission. In such a case, the WTRU may send before the next opportunity, for example, using an LBT configuration associated with the selected SCSt transmission configuration. The WTRU may start a timer when sending before the first available transmission opportunity and may not send (e.g., any) SCSt until the timer expires.

[0084] SCSt configuration selection and side link resource selection can be performed jointly. For example, the WTRU can be configured to jointly select the SCSt configuration and side link resources for data transmission during the side link resource sensing and / or side link resource selection process. For example, after sensing the channel during the sensing window, the WTRU can group the side link resources based on the time difference between the side link data resources and the SCSt resources within the SCSt configuration. If the time difference between the resource and the next SCSt transmission opportunity is less than the first threshold, the WTRU can group the sensed side link resources into a first group. If the corresponding time position of the resource is after the time position of the first SCSt resource and the time difference between the time position of the resource and the second SCSt resource is less than the second threshold, the WTRU can group the sensed side link resources into a second group. If the corresponding SCSt resource is to be used (for example, if a PSFCH is to be sent), the WTRU can select a group that satisfies the PDB. For example, for a short PDB, the WTRU can select one or more side link resources from the first group, and for a longer PDB, the WTRU can select one or more side link resources from the second group.

[0085] Figure 2 An example of grouping the sensed side link resources by the time difference between the sensed side link resources and the SCSt resources is shown.

[0086] The timing relationship between PSSCH transmission and PSFCH transmission may depend on the periodicity of the SCSt configuration. The WTRU may be configured to determine the PSFCH transmission time relative to the PSSCH transmission time based on the available SCSt resource configuration. For example, the WTRU may select a PSFCH transmission time that is the same as the SCSt transmission time within the selected SCSt configuration.

[0087] Multiple WTRUs may transmit using the same SCSt configuration. The WTRU may experience consecutive LBT failures when attempting to access a channel for performing control signal transmission. In some examples, the WTRU may be configured to increase the priority of control signal transmission (e.g., increase the priority of PSFCH transmission) after an LBT failure (e.g., each failure). If the priority of the control signal is increased, the WTRU may use the SCSt configuration or opportunity to send PSFCH. For example, the WTRU may have a PSFCH transmission with priority p3 (e.g., among multiple priorities p1, p2, p3, and p4, where p1 may be the highest priority and p4 may be the lowest priority). The WTRU may attempt to send PSFCH in the first opportunity and may fail due to LBT. The WTRU may increase the priority of PSFCH to p2 and attempt to send PSFCH in the second opportunity. The WTRU may fail again due to another LBT failure and may increase the PSFCH priority to p1. After the priority of PSFCH reaches p1, the WTRU may use the SCSt configuration or opportunity to send PSFCH.

[0088] The SCSt resources may overlap with a channel occupation time (COT) (e.g., an initiated COT). The WTRU may determine that a COT may be initiated by another WTRU, where the time domain resources of the COT may overlap with the SCSt resources (e.g., the WTRU may determine that the COT is initiated based on an SCI sent indicating that the COT is initiated by the other WTRU or based on an indication received from a network device (such as a gNB)). In this case, the WTRU may be configured to use LBT Type 2A or Type 2B (e.g., sensing the channel for a certain duration before transmitting on the SCSt resources), even if the SCSt configuration does not include LBT before transmitting on the SCSt resources. For example, the WTRU may be configured with and / or may select an SCSt configuration that may include configured SCSt resources without LBT. If the WTRU determines that a channel occupation time is initiated (e.g., by decoding an SCI from another WTRU or by receiving an indication from a network device such as a gNB), the WTRU may use LBT Type 2A before transmitting on the SCSt resources. The WTRU may be configured to use LBT Type 2A as part of the SCSt configuration before transmitting the SCSt. The WTRU may be configured to use LBT Type 2A in case of congestion (eg, which may be determined based on measurements of the resource pool).

[0089] The WTRU may be configured to employ or apply a cyclic prefix extension (CPE) before transmitting on the SCSt resources. The length of the CPE may depend on the priority associated with the control signal transmission using the SCSt resources. The length of the CPE may be part of the SCSt configuration and / or may depend on the subcarrier spacing used for sidelink transmissions. The WTRU may be configured to select a CPE from a pool or a set of CPE values. The WTRU may be configured to randomly select a CPE from a pool.

[0090] The WTRU may be configured to indicate the use of the SCSt or the SCSt configuration for the SCSt to one or more other WTRUs. For example, the WTRU may be configured to send side link control information (SCI) indicating whether the WTRU has sent the SCSt corresponding to the SCSt configuration. The WTRU may indicate the number of usage opportunities associated with the SCSt configuration in the SCI. The WTRU may send the indication to the group of WTRUs, for example, using a multicast ID associated with the SCSt configuration (for example, if the WTRU is configured with a group-specific SCSt configuration). The WTRU may indicate in the SSL-SSB whether the sent SCSt corresponds to the SCSt configuration. For example, the WTRU may send the indication in a physical side link broadcast channel that may be multiplexed with the SL-SSB.

[0091] The WTRU may be configured with one or more SCSt configurations, where (e.g., each) SCSt configuration may include a duty cycle and / or transmission time period, a maximum transmission duration, a set of allowed transmission durations, a resource configuration (e.g., including a resource pool configuration), and / or an LBT type. The WTRU may determine whether to use one of the SCSt configurations for control signal transmission (e.g., PSFCH and / or PSCCH transmission) based on the transmission type of the control signal, the broadcast type of the control signal, the priority of the control signal, the resource pool congestion status associated with the control signal, the ongoing COT associated with the control signal, the availability of an option for falling back to a conventional channel access mechanism for the control signal, etc. The WTRU may indicate to other WTRUs (e.g., a WTRU configured to communicate using SL unlicensed spectrum) whether an SCSt transmission opportunity is used.

[0092] The WTRU may determine whether a control signal transmission (e.g., a PSFCH or PSSCH transmission) may qualify as a SCSt and / or which SCSt configuration may be used for the SCSt based on one or more of the transmission type associated with the control signal transmission (e.g., whether the PSSCH transmission is used to schedule a high priority transmission or to indicate a preemption indication), the priority of the control signal transmission, the broadcast type associated with the control signal transmission, the congestion status of the resource pool associated with the control signal transmission (e.g., based on CBR measurement), the ongoing COT, the initiation of a new COT, the availability of SCSt resources and / or PDB (e.g., in terms of time), etc.

[0093] Figure 3 An example is shown where the WTRU may be configured with multiple (eg, two) SCSt configurations and may start COT after the transmission time of the control signal.

[0094] Figure 4 Example operations that may be performed by a WTRU to apply (eg, use) an SCSt configuration are shown. Figure 4 As shown, if the control signal does not qualify as an SCSt (or if the WTRU does not find an SCSt configuration that can be used for the intended control signal transmission), the WTRU may fall back to using the normal channel access mechanism. In this case, the WTRU may fall back to obtaining idle channel access to a channel and sending the control signal over that channel. Figure 4 As shown, the WTRU may indicate to other WTRUs (e.g., via SCI) whether the SCSt configuration and / or SCSt resources (e.g., indicated by the SCSt configuration or determined autonomously by the WTRU) are used for control signal transmission. For example, if the WTRU sends the SCSt based on certain SCSt configuration information received from a network device, the WTRU may send a message to another WTRU, wherein the message may include an indication that the SCSt has been sent based on the SCSt configuration information.

[0095] Although the above features and elements are described in specific combinations, each feature or element may be used alone without the other features and elements of the preferred embodiment, or in various combinations with or without the other features and elements. Although the embodiments described herein may consider 3GPP specific protocols, it should be understood that the implementation described herein is not limited to this scenario and may be applicable to other wireless systems. For example, although the solutions described herein consider LTE, LTE-A, New Radio (NR) or 5G specific protocols, it should be understood that the solutions described herein are not limited to this scenario and are also applicable to other wireless systems.

[0096] The above process may be implemented in a computer program, software, and / or firmware incorporated into 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, read-only memory (ROM), random access memory (RAM), registers, buffer memory, semiconductor storage devices, magnetic media (such as, but not limited to, internal hard disks and removable disks), magneto-optical media, and / or optical media (such as compact disks (CD)-ROM disks and / or digital versatile disks (DVDs)). A processor associated with the software may be used to implement a radio frequency transceiver used in a WTRU, terminal, base station, RNC, and / or any host computer.

Claims

1. A wireless transmit / receive unit WTRU, comprising: A processor, the processor being configured to: Receive configuration information from a network device, wherein the configuration information indicates that the first short control signal transmits SCSt configuration information; determining whether a signal to be transmitted satisfies a condition, wherein the condition is associated with at least a transmission priority associated with the signal; and Based on determining that the signal satisfies the condition, the signal is sent based on the first SCSt configuration information indicated by the configuration information.

2. The WTRU of claim 1 , wherein: The condition is further associated with a broadcast type associated with the signal, a resource pool congestion status associated with the signal, a channel occupancy time associated with the signal, or a packet delay budget associated with the signal.

3. The WTRU of claim 1 or 2, wherein: The first SCSt configuration information indicates one or more of a first duty cycle, a first transmission duration, or a first transmission resource.

4. The WTRU of any one of claims 1 to 3, wherein: The configuration information also indicates second SCSt configuration information, wherein the second SCSt configuration information indicates one or more of a second duty cycle, a second transmission duration, or a second transmission resource, and wherein the processor is configured to send the signal based on the first SCSt configuration information, including the processor being configured to select the first SCSt configuration information rather than the second SCSt configuration information for transmission of the signal.

5. The WTRU of claim 4, wherein: The processor is configured to select the first SCSt configuration information instead of the second SCSt configuration information based on one or more of a broadcast type associated with the signal, a resource pool congestion status associated with the signal, a channel occupancy time associated with the signal, or a packet delay budget associated with the signal.

6. The WTRU of any one of claims 1 to 5, wherein: The processor is also configured to send a message to another WTRU, indicating that the signal has been sent based on the first SCSt configuration information.

7. The WTRU of any one of claims 1 to 6, wherein: The processor is configured to transmit the signal over a channel without obtaining clear channel access to the channel prior to the transmission.

8. The WTRU of any one of claims 1 to 7, wherein: Based on determining that the signal to be transmitted does not satisfy the condition, the processor is configured to obtain idle channel access to a channel and transmit the signal through the channel.

9. The WTRU of any one of claims 1 to 8, wherein: The signal is associated with a physical sidelink feedback channel PSFCH transmission, a physical sidelink control channel PSCCH transmission, a sidelink synchronization signal block S-SSB transmission or a sidelink channel state information CSI transmission.

10. A method implemented by a wireless transmit / receive unit WTRU, the method comprising: Receive configuration information from a network device, wherein the configuration information indicates that the first short control signal transmits SCSt configuration information; determining whether a signal to be transmitted satisfies a condition, wherein the condition is associated with at least a transmission priority associated with the signal; and Based on determining that the signal satisfies the condition, the signal is sent based on the first SCSt configuration information indicated by the configuration information.

11. The method according to claim 10, wherein: The condition is further associated with a broadcast type associated with the signal, a resource pool congestion status associated with the signal, a channel occupancy time associated with the signal, or a packet delay budget associated with the signal.

12. The method according to claim 10 or 11, wherein: The first SCSt configuration information indicates one or more of a first duty cycle, a first transmission duration, or a first transmission resource, wherein the configuration information also indicates second SCSt configuration information, the second SCSt configuration information indicates one or more of a second duty cycle, a second transmission duration, or a second transmission resource, and wherein sending the signal based on the first SCSt configuration information includes selecting the first SCSt configuration information rather than the second SCSt configuration information for transmission of the signal.

13. The method according to claim 12, wherein: The first SCSt configuration information is selected instead of the second SCSt configuration information based on one or more of a broadcast type associated with the signal, a resource pool congestion status associated with the signal, a channel occupancy time associated with the signal, or a packet delay budget associated with the signal.

14. The method according to any one of claims 10 to 13 further includes sending a message to another WTRU, wherein the message indicates that the signal has been sent based on the first SCSt configuration information.

15. The method according to any one of claims 10 to 14, wherein: The signal is associated with a physical sidelink feedback channel PSFCH transmission, a physical sidelink control channel PSCCH transmission, a sidelink synchronization signal block S-SSB transmission or a sidelink channel state information CSI transmission.

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