Method and apparatus for flexible non-periodic SRS transmission

Abstract

To provide a method, apparatus, and system for flexible aperiodic reference signal (RS) transmissions.SOLUTION: A method implemented in a wireless transmit / receive unit (WTRU) for wireless communications comprises: receiving configuration information of one or more sounding reference signal (SRS) resource sets, each SRS resource set of the one or more SRS resource sets is associated with a slot offset and a set of slot offset deltas; receiving downlink control information (DCI) indicating an SRS request, the SRS request indicating an SRS resource set of the one or more SRS resource sets; determining an SRS configuration from a set of SRS configurations for SRS transmissions; determining a slot for transmitting an SRS based on the determined SRS configuration; and transmitting, in the determined slot, the SRS using resources of the indicated SRS resource set.SELECTED DRAWING: Figure 9

Description

Technical Field

[0001] Cross - reference to Related Applications This application claims the priority and benefit of U.S. Provisional Patent Application No. 63 / 049,932, filed with the United States Patent and Trademark Office on July 9, 2020; U.S. Provisional Patent Application No. 63 / 091,597, filed with the United States Patent and Trademark Office on October 14, 2020; and U.S. Provisional Patent Application No. 63 / 169,974, filed with the United States Patent and Trademark Office on April 2, 2021, the entire contents of each of which are incorporated herein by reference as if fully set forth below in their entirety and for all applicable purposes.

Summary of the Invention

[0002] Embodiments disclosed herein generally relate to wireless and / or wired communication networks. For example, one or more embodiments disclosed herein relate to methods and apparatuses for flexible aperiodic sounding reference signal (SRS) transmission.

[0003] In one embodiment, a method implemented in a wireless transmit / receive unit (WTRU) for wireless communication includes receiving configuration information of one or more sounding reference signal (SRS) resource sets, wherein each SRS resource set of the one or more SRS resource sets is associated with a set of slot offset and slot offset delta; receiving downlink control information (DCI) indicating an SRS request indicating an SRS resource set among the one or more SRS resource sets; determining an SRS configuration from a set of SRS configurations for SRS transmission; determining a slot for transmitting the SRS based on the determined SRS configuration; and transmitting the SRS using the resources of the indicated SRS resource set in the determined slot.

Brief Description of the Drawings

[0004] A more detailed understanding can be obtained from the following detailed description, which is given as an example in conjunction with the drawings attached to this specification. The figures in such drawings, as well as the detailed description, are illustrative. Therefore, the figures and detailed explanations should not be considered limiting, and other equally effective examples are possible and likely. Also, similar reference numbers in the figures indicate similar elements. [Figure 1A] This is a system diagram showing an exemplary communication system in which one or more disclosed embodiments may be implemented. [Figure 1B] This is a system diagram showing an exemplary wireless transmit / receive unit (WTRU) that may be used in the communication system shown in Figure 1A, according to one embodiment. [Figure 1C] This is a system diagram showing an exemplary radio access network (RAN) and an exemplary core network (CN) that may be used in the communication system shown in Figure 1A according to one embodiment. [Figure 1D] This is a system diagram showing further exemplary RAN and further exemplary CN that may be used in the communication system shown in Figure 1A according to one embodiment. [Figure 2] This is a slot diagram illustrating the operation of aperiodic SRS transmission according to one or more embodiments. [Figure 3] This figure shows an example of an SRS configuration structure according to one or more embodiments. [Figure 4] This slot diagram shows an example of delta offset instruction by a media access control (MAC) control element (CE), i.e., a MAC CE, according to one or more embodiments. [Figure 5] This figure shows examples of SRS configuration time patterns according to one or more embodiments. [Figure 6] This figure shows an example of using instructions for SRS transmission in a first uplink slot for a subsequent channel occupancy time (COT) according to one or more embodiments. [Figure 7]This figure shows an example of SRS transmission in WTRU acquisition COT according to one or more embodiments. [Figure 8] This slot diagram illustrates an example of a two-stage DCI instruction mechanism for SRS transmission, according to one or more embodiments. [Figure 9] This is a slot diagram illustrating an example of a mode determination mechanism for aperiodic SRS transmission according to one or more embodiments. [Figure 10] This slot diagram illustrates an example of a mechanism using slot format instructions for aperiodic SRS transmission, according to one or more embodiments. [Modes for carrying out the invention]

[0005] The following detailed description includes numerous specific details to provide a complete understanding of the embodiments and / or examples disclosed herein. However, it will be understood that such embodiments and examples may be practiced without some or all of the specific details described herein. In other examples, well-known methods, procedures, components and circuits are not described in detail so as not to obscure the following description. Furthermore, embodiments and examples not specifically described herein may be practiced in place of, or in combination with, embodiments and other examples explicitly, implicitly, and / or essentially (collectively "provided") herein, disclosed, or otherwise provided. While various embodiments are described and / or claimed herein, including apparatus, systems, devices, etc. and / or any elements thereof, performing operations, processes, algorithms, functions, etc. and / or any parts thereof, it should be understood that any embodiment described and / or claimed herein assumes that any apparatus, systems, devices, etc. and / or any elements thereof are configured to perform any operation, process, algorithm, function, etc. and / or any part thereof.

[0006] Communication networks and devices The methods, apparatus, and systems provided herein are well suited to communications involving both wired and wireless networks. Wired networks are well known. Outlines of various types of wireless devices and infrastructure are provided with respect to Figures 1A to 1D, and various elements of a network may be utilized, implemented, deployed, and / or adapted and / or configured for them in accordance with the methods, apparatus, and systems provided herein.

[0007] Figure 1A shows an exemplary 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, message transmission, and broadcast to multiple wireless users. The communication system 100 may enable 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-tail unique-word DFT-Spread OFDM (ZT UW DFT-s OFDM), unique-word OFDM (UW-OFDM), resource block filtering OFDM, and filter bank multicarrier (FBMC).

[0008] As shown in Figure 1A, the communication system 100 may include radio transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, RAN 104 / 113, CN 106 / 115, public switched telephone network (PSTN) 108, the Internet 110, and other networks 112, but it will be understood that the disclosed embodiments intend 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 radio environment. For example, WTRU102a, 102b, 102c, and 102d, any of which may be referred to as “station” and / or “STA”, may be configured to transmit and / or receive radio signals and may include user equipment (UE), mobile stations, fixed or mobile subscriber units, subscriber-based units, pagers, cellular phones, personal digital assistants (PDAs), smartphones, laptops, netbooks, personal computers, radio sensors, hotspots or Mi-Fi devices, Internet of Things (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 radio devices operating in an industrial and / or automated processing chain context), consumer electronics devices, and devices operating on commercial and / or industrial radio networks. Any of WTRU102a, 102b, 102c, and 102d may interchangeably be referred to as UE.

[0009] The communication system 100 may also include base stations 114a and / or base stations 114b. Each of the base stations 114a and 114b may be any type of device configured to wirelessly interface with at least one of the WTRUs 102a, 102b, 102c, and 102d to facilitate access to one or more communication networks, such as CN 106 / 115, the Internet 110, and / or other networks 112. For example, base stations 114a and 114b may be a base transceiver station (BTS), node B, eNodeB, home node B, home eNodeB, gNB, New Radio (NR) node B, site controller, access point (AP), wireless router, etc. Although base stations 114a and 114b are shown as single elements, it will be understood that base stations 114a and 114b may include any number of interconnected base stations and / or network elements.

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

[0011] Base stations 114a and 114b may communicate with one or more WTRUs 102a, 102b, 102c, and 102d via an air interface 116, which may be any suitable radio 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, base stations 114a and WTRUs 102a, 102b, and 102c within RAN 104 / 113 may implement radio technologies such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may establish air interfaces 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 Packet Access (HSDPA) and / or High-Speed ​​UL Packet Access (HSUPA).

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

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

[0015] In one embodiment, base station 114a and WTRU 102a, 102b, 102c may implement multiple radio access technologies. For example, base station 114a and WTRU 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 utilized by WTRU 102a, 102b, 102c may be characterized by multiple types of radio access technologies and / or transmissions transmitted to and from multiple types of base stations (e.g., eNB and gNB).

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

[0017] The base station 114b in FIG. 1A can be, for example, a wireless router, a home Node B, a home eNodeB, or an access point, and can utilize any suitable RAT to facilitate wireless connection in a local area, such as an office, a home, a vehicle, a campus, an industrial facility, an aerial corridor (for use by drones, for example), a road, etc. In one embodiment, the base station 114b and the WTRUs 102c, 102d can implement a wireless technology such as IEEE 802.11 to establish a wireless local area network (WLAN). In one embodiment, the base station 114b and the WTRUs 102c, 102d can implement a wireless 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 can utilize a cellular-based RAT (such as WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.) to establish a pico cell or a femto cell. As shown in FIG. 1A, the base station 114b can have a direct connection to the Internet 110. Thus, the base station 114b may not need to access the Internet 110 via the CN 106 / 115.

[0018] RAN104 / 113 can communicate with CN106 / 115, which may be any type of network configured to provide voice, data, applications, and / or Voice over Internet Protocol (VoIP) services to one or more of WTRU102a, 102b, 102c, and 102d. The data may have various quality of service (QoS) requirements, such as different throughput requirements, latency requirements, error tolerance requirements, reliability requirements, data throughput requirements, and mobility requirements. CN106 / 115 may provide call control, billing services, mobile location-based services, prepaid calls, internet connectivity, video distribution, etc., and / or perform high-level security functions such as user authentication. Although not shown in Figure 1A, it will be understood that RAN104 / 113 and / or CN106 / 115 may communicate directly or indirectly with other RANs employing the same or different RATs as RAN104 / 113. For example, in addition to being connected to RAN104 / 113 which may utilize NR radio technology, CN106 / 115 may also communicate with another RAN (not shown) employing GSM, UMTS, CDMA2000, WiMAX, E-UTRA, or WiFi radio technology.

[0019] CN106 / 115 may also function as a gateway for WTRU102a, 102b, 102c, 102d to access the PSTN108, the Internet 110, and / or other networks 112. The PSTN 108 may include a public switched telephone network that provides plain old telephone service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices, where these networks and devices use a common communication protocol such as the transmission control protocol (TCP), the user datagram protocol (UDP), and / or the internet protocol (IP) of 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 that may employ the same or a different RAT as the RAN 104 / 113.

[0020] Some or all of the WTRU102a, 102b, 102c, 102d in the communication system 100 may include multimode capabilities (e.g., the WTRU102a, 102b, 102c, 102d may include multiple transceivers for communicating with different wireless networks via different wireless links). For example, the WTRU102c shown in Figure 1A may be configured to communicate with a base station 114a that may use cellular-based wireless technology and a base station 114b that may use IEEE802 wireless technology.

[0021] Figure 1B is a system diagram showing an exemplary WTRU102. As shown in Figure 1B, the WTRU102 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 supply 134, a global positioning system (GPS) chipset 136, and / or other peripherals 138. It will be understood that the WTRU102 may include any partial combination of the aforementioned elements while maintaining consistency with one embodiment.

[0022] The processor 118 may be a general-purpose processor, a dedicated processor, a conventional processor, a digital signal processor (DSP), multiple microprocessors, one or more microprocessors associated with a DSP core, a controller, a microcontroller, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) circuit, any other type of integrated circuit (IC), a state machine, etc. The processor 118 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 a transceiver 120 which may be coupled to a transmit / receive element 122. Figure 1B shows the processor 118 and transceiver 120 as separate components, but it will be understood that the processor 118 and 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., base station 114a) via the air interface 116. For example, in one embodiment, the transmit / receive element 122 may be an antenna configured to transmit and / or receive RF signals. In one embodiment, the transmit / receive element 122 may be an emitter / detector configured to transmit and / or receive, for example, IR, UV, or visible light signals. In yet another embodiment, the transmit / receive element 122 may be configured to transmit and / or receive both RF signals and optical signals. It will be understood that the transmit / receive element 122 may be configured to transmit and / or receive any combination of radio signals.

[0024] Although the transmit / receive element 122 is shown as a single element in Figure 1B, the WTRU 102 may include any number of transmit / receive elements 122. More specifically, the WTRU 102 may utilize 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 radio signals via the air interface 116.

[0025] The transceiver 120 may be configured to modulate the signal transmitted by the transmit / receive element 122 and demodulate the signal received by the transmit / receive element 122. As described above, the WTRU 102 may have multimode capability. Therefore, the transceiver 120 may include multiple transceivers to enable the WTRU 102 to communicate via multiple RATs, such as NR and IEEE 802.11.

[0026] The processor 118 of the WTRU102 may be coupled to a speaker / microphone 124, a keypad 126, and / or a display / touchpad 128 (e.g., a liquid crystal display (LCD) display unit or an organic light-emitting diode (OLED) display unit) and may receive user input data from them. The processor 118 may also output user data to the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128. Furthermore, the processor 118 may access information from any type of suitable memory, such as non-removable memory 130 and / or removable memory 132, and store data in such memory. The non-removable memory 130 may include random-access memory (RAM), read-only memory (ROM), a hard disk, or any other type of memory storage device. 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 in memory that is not physically located on the WTRU 102, such as on a server or home computer (not shown), and store data in such memory.

[0027] The processor 118 may receive power from the power supply 134 and be configured to distribute and / or control power to other components within the WTRU 102. The power supply 134 may be any suitable device for supplying power to the WTRU 102. For example, the power supply 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.), a solar cell, a fuel cell, 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) about the current location of the WTRU 102. In addition to or instead of the information from the GPS chipset 136, the WTRU 102 may receive location information from base stations (e.g., base stations 114a, 114b) via 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 understood that the WTRU 102 may acquire location information by any preferred location determination method while maintaining consistency with one embodiment.

[0029] The processor 118 may be further coupled to other peripherals 138, which may include one or more software and / or hardware modules that provide additional features, functions, and / or wired or wireless connectivity. For example, 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 modulated (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, and the like. The peripheral device 138 may include one or more sensors, which may be one or more of the following: gyroscope, accelerometer, Hall effect sensor, magnetometer, compass sensor, proximity sensor, temperature sensor, time sensor, geolocation sensor, altimeter, light sensor, touch sensor, magnetometer, barometer, gesture sensor, biometric sensor, and / or humidity sensor.

[0030] WTRU102 may include a full-duplex radio in which the transmission and reception of some or all of the signals (e.g., associated with specific subframes for both UL (e.g., transmission) and downlink (e.g., reception)) may be parallel and / or simultaneous. The full-duplex radio may include an interference management unit 139 for reducing and / or substantially eliminating self-interference via either hardware (e.g., chokes) or signal processing via a processor (e.g., via a separate processor (not shown) or processor 118). In one embodiment, WRTU102 may include a half-duplex radio for the transmission and reception of any of the signals (e.g., associated with specific subframes for either UL (e.g., transmission) or downlink (e.g., reception)).

[0031] Figure 1C is a system diagram showing RAN104 and CN106 according to one embodiment. As described above, RAN104 can communicate with WTRU102a, 102b, and 102c via the air interface 116 using E-UTRA wireless technology. RAN104 can also communicate with CN106.

[0032] RAN104 may include eNode-B160a, 160b, and 160c, but it will be understood that RAN104 may include any number of eNode-B while maintaining consistency with one embodiment. Each of eNode-B160a, 160b, and 160c may include one or more transceivers for communicating with WTRU102a, 102b, and 102c via the air interface 116. In one embodiment, eNode-B160a, 160b, and 160c may implement MIMO technology. Thus, eNode-B160a may, for example, use multiple antennas to transmit radio signals to and / or receive radio signals from WTRU102a.

[0033] Each of the eNode-B160a, 160b, and 160c may be associated with a specific cell (not shown) and may be configured to handle wireless resource management decisions, handover decisions, user scheduling, etc., in UL and / or DL. As shown in Figure 1C, the eNodes B160a, 160b, and 160c may communicate with each other via the X2 interface.

[0034] The CN106 shown in Figure 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 aforementioned elements is shown as part of CN106, 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 MME162 can be connected to each of the eNode-B160a, 160b, and 160c within RAN104 via the S1 interface and can function as a control node. For example, the MME162 may perform roles such as authenticating users of WTRU102a, 102b, and 102c, activating / deactivating bearers, and selecting gateways for specific services during the initial attachment of WTRU102a, 102b, and 102c. The MME162 may provide control plane functionality for switching between RAN104 and other RANs (not shown) employing other radio technologies such as GSM and / or WCDMA.

[0036] The SGW164 can be connected to each of the eNode-B160a, 160b, and 160c within RAN104 via the S1 interface. The SGW164 can generally route and forward user data packets to and from WTRU102a, 102b, and 102c. The SGW164 can perform other functions, such as anchoring the user plane during eNode-B handovers, triggering paging when DL data is available to WTRU102a, 102b, and 102c, and managing and remembering the context of WTRU102a, 102b, and 102c.

[0037] SGW164 may be connected to PGW166, which may provide WTRU102a, 102b, and 102c with access to a packet-switched network such as the Internet 110 to facilitate communication between WTRU102a, 102b, and 102c and IP-enabled devices.

[0038] CN106 can facilitate communication with other networks. For example, CN106 can provide WTRU102a, 102b, and 102c with access to a circuit-switched network such as PSTN108 to facilitate communication between WTRU102a, 102b, and 102c and conventional terrestrial line communication devices. For example, CN106 may include or communicate with an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that acts as an interface between CN106 and PSTN108. Furthermore, CN106 may provide WTRU102a, 102b, and 102c with access to another network 112, which may include other wired and / or wireless networks owned and / or operated by other service providers.

[0039] Although the WTRU is shown as a wireless terminal in Figures 1A to 1D, in certain representative embodiments, such a terminal is intended to be able to use a wired communication interface with a communication network (e.g., temporarily or permanently).

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

[0041] A WLAN in Infrastructure Basic Service Set (BSS) mode may have access points (APs) of the BSS and one or more stations (STAs) associated with the APs. APs may have access to or interfaces with a Distribution System (DS) or another type of wired / wireless network that carries traffic entering and / or leaving the BSS. Traffic originating outside the BSS and destined for an STA may reach and be delivered to the STA via an AP. Traffic originating from an STA to a destination outside the BSS may be sent to an AP and then delivered to its respective destination. Traffic between STAs within the BSS may be transmitted, for example, via an AP; a source STA may send traffic to an 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 transmitted between a source STA and a destination STA (for example, directly between them) via a direct link setup (DLS). In certain representative embodiments, the DLS may use 802.11e DLS or 802.11z tunneled DLS (TDLS). A WLAN using Independent BSS (IBSS) mode may not have APs, and STAs within or using IBSS (e.g., all STAs) may communicate directly with each other. The IBSS mode of communication may be referred to herein as “ad hoc” communication mode.

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

[0043] A high-throughput (HT) STA can form a 40MHz wide channel for communication, for example, by using a 40MHz wide channel through a combination of a primary 20MHz channel and adjacent or non-adjacent 20MHz channels.

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

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

[0046] WLAN systems that can support multiple channels and channel bandwidths, such as 802.11n, 802.11ac, 802.11af, and 802.11ah, include a channel that can be designated as the primary channel. 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 an STA from among all STAs operating in a BSS that support the minimum bandwidth operating mode. In the 802.11ah example, the primary channel may be 1 MHz wide for an STA (e.g., an MTC type device) that supports (e.g., only) the 1 MHz mode, even if other STAs in the AP and 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. For example, if the primary channel is busy due to an STA (which only supports 1MHz operating mode) transmitting to the AP, a large portion of the frequency band may remain idle and could be considered busy, even if it were available.

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

[0048] Figure 1D is a system diagram showing RAN113 and CN115 according to one embodiment. As described above, RAN113 can communicate with WTRU102a, 102b, and 102c via air interface 116 using NR radio technology. RAN113 can also communicate with CN115.

[0049] RAN113 may include gNB180a, 180b, and 180c, but it will be understood that RAN113 may include any number of gNBs while maintaining consistency with one embodiment. Each of gNB180a, 180b, and 180c may include one or more transceivers for communicating with WTRU102a, 102b, and 102c via the air interface 116. In one embodiment, gNB180a, 180b, and 180c may implement MIMO technology. For example, gNB180a and 108b may use beamforming to transmit and / or receive signals to gNB180a, 180b, and 180c. Thus, gNB180a may, for example, use multiple antennas to transmit and / or receive radio signals from WTRU102a. In one embodiment, gNB180a, 180b, and 180c may implement carrier aggregation technology. For example, gNB180a may transmit multiple component carriers to WTRU102a (not shown). A subset of these component carriers may be on the unauthorized spectrum, and the remaining component carriers may be on the authorized spectrum. In one embodiment, gNB180a, 180b, and 180c may implement coordinated multi-point (CoMP) technology. For example, WTRU102a may receive coordinated transmissions from gNB180a and gNB180b (and / or gNB180c).

[0050] WTRU102a, 102b, and 102c may communicate with gNB180a, 180b, and 180c using transmissions associated with scalable numerology. For example, OFDM symbol intervals and / or OFDM subcarrier intervals may vary for different transmissions, different cells, and / or different portions of the radio transmission spectrum. WTRU102a, 102b, and 102c may communicate with gNB180a, 180b, and 180c using subframes or transmission time intervals (TTIs) of varying or scalable lengths (e.g., containing varying numbers of OFDM symbols and / or having varying absolute time durations).

[0051] gNB180a, 180b, and 180c can be configured to communicate with WTRU102a, 102b, and 102c in standalone and / or non-standalone configurations. In a standalone configuration, WTRU102a, 102b, and 102c can communicate with gNB180a, 180b, and 180c without accessing other RANs (e.g., e-nodes B160a, 160b, and 160c). In a standalone configuration, WTRU102a, 102b, and 102c can utilize one or more of gNB180a, 180b, and 180c as mobility anchor points. In a standalone configuration, WTRU102a, 102b, and 102c can communicate with gNB180a, 180b, and 180c using signals in unlicensed bands. In a non-standalone configuration, WTRU102a, 102b, and 102c can communicate with and connect to gNB180a, 180b, and 180c, while also communicating with and connecting to other RANs such as enodes B160a, 160b, and 160c. For example, WTRU102a, 102b, and 102c can implement DC principles for substantially simultaneous communication with one or more gNB180a, 180b, and 180c and one or more enodes B160a, 160b, and 160c. In a non-standalone configuration, enodes B160a, 160b, and 160c can function as mobility anchors for WTRU102a, 102b, and 102c, while gNB180a, 180b, and 180c can provide additional coverage and / or throughput to service WTRU102a, 102b, and 102c.

[0052] Each of the gNB180a, 180b, and 180c may be associated with a specific cell (not shown) and may be configured to handle wireless resource management decisions, handover decisions, user scheduling in UL and / or DL, support for network slicing, dual connectivity, interworking between NR and E-UTRA, routing of user plane data to User Plane Functions (UPFs) 184a and 184b, and routing of control plane information to Access and Mobility Management Functions (AMFs) 182a and 182b. As shown in Figure 1D, the gNB180a, 180b, and 180c may communicate with each other via the Xn interface.

[0053] The CN115 shown in Figure 1D may include at least one AMF182a, 182b, at least one UPF184a, 184b, at least one Session Management Function (SMF)183a, 183b, and optionally a Data Network (DN)185a, 185b. Although each of the aforementioned elements is shown as part of the CN115, it will be understood that any of these elements may be owned and / or operated by entities other than the CN operator.

[0054] AMF182a and 182b can be connected to one or more gNB180a, 180b, and 180c within RAN113 via the N2 interface and can function as control nodes. For example, AMF182a and 182b can perform roles such as user authentication for WTRU102a, 102b, and 102c, support network slicing (e.g., handling different PDU sessions with different requirements), selection of specific SMF183a and 183b, management of registration areas, termination of NAS signaling, and mobility management. Network slicing can be used by AMF182a and 182b to customize CN support for WTRU102a, 102b, and 102c based on the type of service utilizing WTRU102a, 102b, and 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, and / or similar. AMF182 may provide control plane functionality for switching between RAN113 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] SMF183a and 183b can be connected to AMF182a and 182b in CN115 via the N11 interface. SMF183a and 183b can also be connected to UPF184a and 184b in CN115 via the N4 interface. SMF183a and 183b can select and control UPF184a and 184b and configure the routing of traffic through UPF184a and 184b. SMF183a and 183b can perform other functions such as managing and assigning UE IP addresses, managing PDU sessions, controlling policy enforcement and QoS, and providing downlink data notifications. PDU session types can be IP-based, non-IP-based, Ethernet-based, etc.

[0056] UPF184a, 184b may be connected via the N3 interface to one or more gNB180a, 180b, 180c in RAN113, which may provide WTRU102a, 102b, 102c with access to a packet-switched network such as the Internet 110 to facilitate communication between WTRU102a, 102b, 102c and IP-enabled devices. UPF184, 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, and providing mobility anchoring.

[0057] CN115 can facilitate communication with other networks. For example, CN115 may include or communicate with an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that functions as an interface between CN115 and PSTN108. Furthermore, CN115 may provide WTRU102a, 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, WTRU102a, 102b, 102c may be connected to local data networks (DNs) 185a, 185b via UPF184a, 184b through an N3 interface to UPF184a, 184b, and an N6 interface between UPF184a, 184b and DN185a, 185b.

[0058] In view of Figures 1A to 1D and their corresponding descriptions, one or more of the functions described herein may be performed by one or more emulation devices (not shown) with respect to one or more of the WTRU102a to d, base stations 114a to b, eNode-B160a to c, MME162, SGW164, PGW166, gNB180a to c, AMF182a to b, UPF184a to b, SMF183a to b, DN185a to b, and / or any other devices described herein. An emulation device may be one or more devices configured to emulate one or more 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.

[0059] Emulation devices may be designed to implement testing of one or more other devices in a laboratory and / or 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 network to test other devices in a communications 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 network. Emulation devices may be directly coupled to another device for testing purposes and / or may perform testing using terrestrial radio communication.

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

[0061] Sounding Reference Signal (SRS) transmission Sounding reference signals (SRS) are primarily used for uplink channel measurements. SRS transmissions can also be used to assist in downlink channel status information (CSI) estimation for partial or complete mutual channels. Furthermore, SRS can be used for beam management, where SRS transmissions through different SRS resources support beam selection by a network (e.g., gNB). Therefore, enabling dynamic and flexible sounding procedures with appropriate capacity and coverage is essential for MIMO systems (e.g., improving MIMO performance).

[0062] In 5G New Radio (NR) (e.g., NR Release 16), a WTRU (e.g., UE) may consist of one or more SRS resource sets (e.g., SRS-ResourceSet) containing up to K SRS resources, where K is based on the WTRU's (e.g., UE's) capabilities. SRS resource sets may be configured for different applications (e.g., usage), such as beamManagement, codebook, nonCodebook, or antennaSwitching. In some examples, the time-domain behavior of an SRS resource configuration is indicated by the higher-layer parameter resourceType. Time-domain behavior can be configured as periodic, semi-persistent, and / or aperiodic. In NR (e.g., NR Release 16), a WTRU cannot have different time-domain behaviors (e.g., periodic and semi-persistent), and in some cases, a WTRU cannot have different periodicities for SRS resources within the same SRS resource set.

[0063] In some cases, aperiodic SRS has higher transmission priority than periodic SRS and / or semi-persistent SRS when triggered to transmit an SRS on the same symbol as a WTRU. In some cases, aperiodic SRS has priority over physical uplink control channel (PUCCH) when triggered to transmit an aperiodic SRS on the same symbol also used for PUCCH, except when PUCCH is carrying a hybrid automatic retransmission request (HARQ) (e.g., HARQ-ACK or NACK), a link recovery request, and / or a scheduling request (SR).

[0064] In semi-persistent SRS operation, the WTRU can be activated / deactivated by downlink control information (DCI) to start / stop SRS transmission. However, the impact of false detection of the deactivation signal can be significant, as it may cause the WTRU to continue transmitting SRS, which can lead to unnecessary interference and WTRU battery consumption.

[0065] Figure 2 illustrates the exemplary operation of an aperiodic SRS transmission. In an aperiodic SRS configuration, the WTRU (e.g., UE) may receive a set of upper-layer parameters for the SRS-ResourceSet, including, for example, slotOffset, srs-ResourceSetId, AperiodicSRS-ResourceTrigger, and / or AperiodicSRS-ResourceTriggerList. Aperiodic SRS transmissions can be triggered by a WTRU-specific DCI, a group-common DCI, or an uplink DCI. The associated SRS request field (e.g., a 2-bit SRS request field) in DCI formats 0_1, 1_1, 0_2 (if an SRS request field exists), and 1_2 (if an SRS request field exists) may trigger the corresponding SRS transmission.

[0066] 3. Based on the GPP standard (e.g., 3 GPP TS 38.214, Release 16), if the WTRU receives a DCI that triggers an aperiodic SRS in slot n, the WTRU will send an aperiodic SRS in each of the triggered SRS resource sets in the following slots:

[0067]

number

[0068] In some current implementations, when a WTRU receives a DCI that triggers an aperiodic SRS, the slot level offset for sending the aperiodic SRS depends on slotOffset, a higher-layer parameter configured by radio resource control (RRC) signaling. Relying on RRC configuration values ​​for determining the transmit slot for aperiodic SRS imposes certain limitations on the performance of the radio communication system. For example, if the indicated slot offset occurs within a downlink (DL) slot, the intended SRS transmit is ignored, and the scheduler must retry for another opportunity. In another example, in a multi-user MIMO (MU-MIMO) system, several users may be triggered to take part in simultaneous aperiodic SRS transmits to provide the scheduler with accurate channel and interference estimates. However, triggering all WTRUs simultaneously (with several simultaneous DCI transmits) can cause congestion on the downlink control channel or DL ​​transmits.

[0069] By allowing the slot level offset of aperiodic SRS to be configured by Layer 1 (L1), potential collisions between SRS transmissions and other transmissions can be avoided. Thus, aperiodic SRS can be transmitted more flexibly and reliably with less overhead and latency. Therefore, to further increase the flexibility of aperiodic SRS, it is desirable to dynamically control SRS transmissions, for example, extended control of the SRS triggering offset.

[0070] Two-stage offset instruction In various embodiments, a WTRU configured for aperiodic SRS transmission can determine a slot for aperiodic SRS transmission in two steps. In the example, the WTRU may consist of or be shown two or more sets of information for determining the slot index for SRS transmission.

[0071] -RRC configuration delta offset value In various embodiments, the WTRU may receive a first configuration (e.g., SRS configuration) including a slotOffset value (k) via RRC signaling and a second configuration (e.g., slotOffset_delta) via RRC signaling. The second configuration may include one or more delta offset values ​​that can be used to correct a first set of RRC configuration offset values ​​(e.g., slotOffsetk received in the first configuration or determined from the first configuration). To trigger aperiodic SRS transmission, the WTRU may receive a media access control (MAC) control element (CE) having a field (e.g., n bits) for indicating DCI or slotOffset_delta, where each state of the DCI or MAC CE field can be used as an index for a specific configuration delta offset value (Δk) in the configuration slotOffset_delta. The WTRU can determine a slot index for aperiodic SRS transmission by combining the indicated slotOffset and slotOffset_delta values, e.g., k + Δk.

[0072] Figure 3 shows an example of an SRS configuration structure in NR. As shown in Figure 3, an SRS configuration (e.g., an overall RRC SRS configuration) may be divided into three different levels of properties: SRS-Config, SRS-ResourceSet, and SRS-Resource, where high-level properties, behavioral properties, and resource-level properties are defined, respectively.

[0073] In one embodiment, the WTRU may be configured as slotOffset_delta as part of the SRS-Config. Thus, the configured slotOffset_delta may be applied to all SRS resource sets and / or SRS resources.

[0074] In one embodiment, a WTRU may be configured as slotOffset_delta as part of an SRS-ResourceSet. Therefore, the configured slotOffset_delta may only apply to the configured SRS resources in that SRS resource set.

[0075] In another embodiment, the WTRU may be configured as slotOffset_delta as part of the SRS-Resource configuration. Thus, the configuration slotOffset_delta may apply only to a specific configuration SRS resource in the SRS resource set.

[0076] In one embodiment, the delta offset value may be configured at one or more levels of the SRS configuration. In the example, the WTRU may consist of two delta offset values ​​configured in the SRS-ResourceSet and SRS-Resource. Thus, the received DCI or MAC CE field may point to a specific combination of configured offset values ​​in the SRS-ResourceSet and SRS-Resource.

[0077] -MAC CE indicated delta offset value In one embodiment, the WTRU may receive a first configuration (e.g., an SRS configuration via RRC signaling) including a slotOffset value (k), and a second configuration (e.g., slotOffset_delta) indicated by a MAC CE showing one or more delta offset values. In some examples, the offset value indicated by the MAC CE may include or indicate one or more delta offset values.

[0078] As shown in Figure 4, the WTRU may receive a MAC CE (including slotOffset_delta) before or after (or on the same slot as) a DCI that triggers a non-periodic SRS transmission. In one embodiment, one or more delta offset values ​​indicated by slotOffset_delta in the MAC CE may remain valid until updated (e.g., by the network, scheduler, or gNB).

[0079] In one embodiment, the WTRU may consist of a time-validation window, referring to the reception of a physical downlink control channel (PDCCH) (or DCI) that triggers a non-periodic SRS transmission, so that the WTRU can consider slotOffset_delta (indicated by the MAC CE) only if, for example, the MAC CE is received within the time-validation window. In the example, the time-validation window may be defined by two integer values, where, with respect to "slot n" from which the PDCCH that triggers a non-periodic SRS is received, the first integer value may define the start of the window and the second integer value may define the end of the window.

[0080] In one embodiment, the WTRU may receive an explicit instruction (e.g., a DCI flag) or an implicit instruction (e.g., an operating mode to consider), or alternatively, it may ignore the slotOffset_delta indicated by the MAC CE.

[0081] In various embodiments, when a WTRU receives a slotOffset_delta containing two or more delta offset values ​​via MAC CE, the WTRU may receive a DCI having an m-bit field to trigger an aperiodic SRS transmission. Each state in the DCI field may be used as an index for a specific configuration delta offset value (Δk) in slotOffset_delta. The WTRU can determine the slot index for an aperiodic SRS transmission by combining the indicated slotOffset and slotOffset_delta values, for example, k+Δk.

[0082] In various embodiments, when a WTRU receives slotOffset_delta containing a single delta offset value via MAC CE, the WTRU can receive DCI to trigger an aperiodic SRS transmission. The WTRU can determine the slot index for an aperiodic SRS transmission by directly combining the indicated slotOffset and slotOffset_delta values, for example, k+Δk.

[0083] In one embodiment, a WTRU can receive a group common DCI and simultaneously trigger aperiodic SRS transmissions to several users (e.g., multiple WTRUs), and each WTRU in the group can receive its own MAC CE containing a different slotOffset_delta to indicate a corresponding delta offset value for adjusting the individual RRC configuration slotOffset.

[0084] -The delta offset value is implicitly indicated. In one embodiment, the WTRU can receive a first configuration (e.g., an SRS configuration via RRC signaling) including a slotOffset value (k), and implicitly receive or determine a second configuration. The second configuration may include one or more parameters (e.g., slotOffset_delta) indicating a delta offset value for correcting the first configuration offset value (e.g., a value such as slotOffset received from the SRS configuration via RRC signaling). In the example, the WTRU can receive a DCI scrambled with the corresponding radio network temporary identifier (RNTI) via an index to a set of RRC configuration slotOffset_delta values, either directly corresponding to a specific slotOffset_delta value or, as described herein (e.g., in the previous section, "RRC Configuration Delta Offset Values"). In another example, the WTRU may consist of two or more search spaces and / or CORESETs, each of which may correspond directly to a slotOffset_delta or, as described herein (e.g., in the previous section "RRC Configuration Delta Offset Values"), via an index to a set of RRC configuration slotOffset_deltas.

[0085] Single DCI instruction In various embodiments, an SRS resource set may be interchangeably referred to as an SRS resource.

[0086] - Extended SRS configuration In a non-periodic SRS configuration, the WTRU can receive a set of upper-layer parameters for the SRS-ResourceSet, including one of the following: slotOffset, srs-ResourceSetId, AperiodicSRS-ResourceTrigger, and AperiodicSRS-ResourceTriggerList. Non-periodic SRS transmissions can be triggered by a WTRU-specific DCI, a group-common DCI, or an uplink DCI.

[0087] In various embodiments, a WTRU whose usage is set to codebook or noncodebook may consist of two or more SRS resource sets (e.g., multiple SRS resource sets or SRS resources), each SRS resource set may consist of a different slotOffset value. In one embodiment, an SRS resource set indicator (e.g., indicated by DCI or MAC CE) may indicate which SRS resource set should be used for aperiodic SRS transmission.

[0088] In various embodiments, a WTRU whose usage is set to codebook or noncodebook may consist of three or more SRS resources, each SRS resource may consist of a different slotOffset_resource value. Each configuration slotOffset_resource may be used as a replacement for a configuration slotOffset in an SRS-ResourceSet, or as a correction to a configuration slotOffset.

[0089] - Reuse of existing DCI format In various embodiments, the WTRU may determine one or more slot offsets for the SRS resource set based on one or more of the following:

[0090] In one embodiment, the WTRU can determine one or more slot offsets for an SRS resource set based on one or more dedicated DCI formats. a) For example, a WTRU can dynamically determine a slot offset for an SRS resource based on one or more dedicated DCI formats (e.g., one or more of DCI format 0_3, DCI format 1_3, and DCI format 2_7). One or more dedicated DCI formats may include one or more of the following: i) Non-SUL / SUL indicator: (1) In one embodiment, if the WTRU is composed of a cell having a plurality of uplinks (ULs), the WTRU can determine one or more of the plurality of ULs based on an indicator. For example, if the WTRU receives a first instruction based on an indicator, the WTRU can determine a first uplink (e.g., a non-auxiliary uplink). If the WTRU receives a second instruction based on an indicator, the WTRU can determine a second uplink (e.g., an auxiliary uplink). ii) SRS request: (1) In one embodiment, the WTRU may decide to transmit an SRS based on an indicator. For example, if the WTRU receives a first instruction based on an indicator, the WTRU may transmit a first set of SRS resource sets. If the WTRU receives a second instruction based on an indicator, the WTRU may transmit a second set of SRS resource sets. (2) In one embodiment, the WTRU may decide to transmit an SRS based on an indicator. For example, if the WTRU receives a first instruction based on an indicator, the WTRU may not transmit an SRS resource set. If the WTRU receives a second instruction based on an indicator, the WTRU may transmit a first set of SRS resources. If the WTRU receives a third instruction based on an indicator, the WTRU may transmit a second set of SRS resources. iii) Transmit Power Control (TPC) commands: (1) In one embodiment, the WTRU can determine the transmit power of the SRS resource set based on an indicator. For example, if the WTRU receives a first instruction based on an indicator, the WTRU can determine a first transmit power of the SRS resource set. If the WTRU receives a second instruction based on an indicator, the WTRU can determine a second power of the SRS resource set. iv) Slot offset for SRS resource sets (e.g., slot offset for all triggered SRS resource sets): (1) In one embodiment, the WTRU may determine a slot offset for a triggered SRS resource set (e.g., via an SRS request) based on an indicator. For example, if the WTRU receives a first instruction based on an indicator, the WTRU may determine a first slot offset. If the WTRU receives a second instruction based on an indicator, the WTRU may determine a second slot offset. (2) The determination of the slot offset may be based on one or more of the following: (a) Predefined slot offset for the indicated value (b) Pre-configured slot offset for the indicated value (c) Explicit indication of slot offset. v) Slot offset for the SRS resource set (e.g., a specific slot offset for the SRS resource set among the triggered SRS resource sets): (1) In one embodiment, the WTRU may determine one or more slot offsets for a triggered SRS resource set (e.g., via an SRS request) based on a set of indicators. For example, if the WTRU receives a first set of indicators, the WTRU may determine a first set of slot offsets. If the WTRU receives a second set of indicators, the WTRU may determine a second set of slot offsets. (a) The number of slot offsets may be equal to the number of triggered SRS resource sets. (b) If the number of slot offsets is greater than the number of triggered SRS resource sets, the WTRU may apply the slot offsets to all triggered SRS resource sets or to triggered SRS resource sets not associated with any slot offsets, based on one or more of the following: (i) Do not apply slot offset (ii) Apply the default slot offset (iii) Apply the average value of the indicated slot offset. (iv) Apply the first / last slot offset of the indicated slot offset. (c) If the number of slot offsets is less than the number of SRS resource sets that were triggered, the WTRU may indicate a specific value (e.g., 0 or 1) for one or more indicators that are not associated with any of the triggered SRS resource sets. (2) The determination of the slot offset may be based on one or more of the following: (a) Predefined slot offset for the indicated value (b) Pre-configured slot offset for the indicated value (c) Explicit indication of slot offset. (3) The WTRU may apply a determined set of slot offsets based on the determined slot offset (e.g., delta offset). For example, if the WTRU simultaneously receives a first slot offset for a triggered SRS resource set (e.g., a slot offset for all triggered SRS resource sets) and a second slot offset for the first SRS resource set of the triggered SRS resource set, the WTRU may apply the first slot offset for all triggered SRS resource sets and the second slot offset for the first SRS resource set based on the first slot offset.

[0091] In one embodiment, the WTRU can determine one or more slot offsets for an SRS resource set based on one or more existing DCI formats. a) For example, WTRU can dynamically determine slot offsets for SRS resources based on one or more existing DCI formats (e.g., one or more of DCI format 0_1, DCI format 0_2, DCI format 1_1, DCI format 1_2, and DCI format 2_3). b) WTRU may determine one or more existing DCI formats as slot offset indicated DCIs based on one or more of the following: i) RNTI. (1) In one embodiment, if the DCI is scrambled with a first RNTI (e.g., SRS-RNTI), the WTRU may determine the DCI to be a DCI that includes one or more SRS slot offset instructions. If the DCI is scrambled with a second RNTI (e.g., C-RNTI, CS-RNTI, etc.), the WTRU may determine the DCI to be a DCI that has other purposes (e.g., PDSCH / PUSCH scheduling, configuration grant activation / release, semi-persistent CSI activation / deactivation, TPC commands, etc.). ii) HARQ process number. (1) In one embodiment, if the HARQ process number is set to a first specific bit (e.g., all "0"), the WTRU may determine the DCI to be a DCI that includes one or more SRS slot instructions. If the HARQ process number is not set to a first specific bit, the WTRU may determine the DCI to be a DCI that has other purposes (e.g., PDSCH / PUSCH scheduling, configuration grant activation / release, semi-persistent CSI activation / deactivation, TPC command, etc.). iii) A redundant version. (1) In one embodiment, if the redundant version is set to a first specific bit (e.g., all "0"), the WTRU may determine the DCI as a DCI that includes one or more SRS slot instructions. If the redundant version is not set to a first specific bit, the WTRU may determine the DCI as a DCI that has other purposes (e.g., PDSCH / PUSCH scheduling, configuration grant activation / release, semi-persistent CSI activation / deactivation, TPC commands, etc.). iv) Modulation and coding schemes. (1) In one embodiment, if the modulation and coding scheme is set to a first specific bit (e.g., all "0"), the WTRU may determine the DCI as a DCI that includes one or more SRS slot indications. If the modulation and coding scheme is not set to a first specific bit, the WTRU may determine the DCI as a DCI that has other purposes (e.g., PDSCH / PUSCH scheduling, configuration grant activation / release, semi-persistent CSI activation / deactivation, TPC commands, etc.). v) Frequency domain resource allocation. (1) In one embodiment, if the frequency domain resource allocation is set to a first specific bit (e.g., all "0"), the WTRU may determine the DCI as a DCI that includes one or more SRS slot indications. If the frequency domain resource allocation is not set to a first specific bit, the WTRU may determine the DCI as a DCI that has other purposes (e.g., PDSCH / PUSCH scheduling, configuration grant activation / release, semi-persistent CSI activation / deactivation, TPC commands, etc.). c) If the WTRU determines that the DCI is a DCI that includes one or more slot offset indications, one or more of the following fields may be used for one or more slot offset indications: (1) Frequency domain resource allocation. (2) Time domain resource allocation. (3) Downlink assignment index (e.g., the first and / or second). (4) Precoding information and number of layers. d) One or more slot offset instructions may include one or more of the following: i) Slot offset for the SRS resource set (e.g., slot offset for all triggered SRS resource sets) (1) In one embodiment, the WTRU may determine a slot offset for a triggered SRS resource set (e.g., via an SRS request) based on an indicator. For example, if the WTRU receives a first instruction based on an indicator, the WTRU may determine a first slot offset. If the WTRU receives a second instruction based on an indicator, the WTRU may determine a second slot offset. (2) The determination of the slot offset may be based on one or more of the following: (a) Predefined slot offset for the indicated value (b) Pre-configured slot offset for the indicated value (c) Explicit indication of slot offset. ii) Slot offset for the SRS resource set (for example, a specific slot offset for the SRS resource set among the triggered SRS resource sets) (1) In one embodiment, the WTRU may determine one or more slot offsets for a triggered SRS resource set (e.g., via an SRS request) based on a set of indicators. For example, if the WTRU receives a first set of indicators, the WTRU may determine a first set of slot offsets. If the WTRU receives a second set of indicators, the WTRU may determine a second set of slot offsets. (a) The number of slot offsets may be equal to the number of triggered SRS resource sets. (b) If the number of slot offsets is greater than the number of triggered SRS resource sets, the WTRU may apply the slot offsets to all triggered SRS resource sets or to triggered SRS resource sets not associated with any slot offsets, based on one or more of the following: 1. Do not apply slot offset. 2. Apply the default slot offset. 3. Apply the average value of the indicated slot offset. 4. Apply the first / last slot offset of the indicated slot offset. (c) If the number of slot offsets is less than the number of triggered SRS resource sets, the WTRU may indicate a specific value (e.g., 0 or 1) for indicators not associated with any triggered SRS resource sets. (2) The determination of the slot offset may be based on one or more of the following: (a) Predefined slot offset for the indicated value (b) Pre-configured slot offset for the indicated value (c) Explicit indication of slot offset. (3) The WTRU may apply a determined set of slot offsets based on the determined slot offset (e.g., delta offset). For example, if the WTRU simultaneously receives a first slot offset for a triggered SRS resource set (e.g., a slot offset for all triggered SRS resource sets) and a second slot offset for the first SRS resource set of the triggered SRS resource set, the WTRU may apply the first slot offset for all triggered SRS resource sets and the second slot offset for the first SRS resource set based on the first slot offset.

[0092] Pre-slot instructions In various embodiments, a WTRU can receive instructions to transmit an SRS in a time resource belonging to a set of possible time opportunities for an SRS configured by a higher layer. These solutions may allow the network to trigger SRS transmissions from multiple UEs within the same slot without excessive overhead or time scheduling limitations in the DCI.

[0093] - SRS configuration time pattern A WTRU may consist of at least one set of resources in the time domain for possible transmissions of an SRS. Each such set may be referred to hereafter as an "SRS configuration time pattern". Each SRS configuration time pattern may be associated with an index. For example, an SRS configuration time pattern may consist of a set of time symbols or a set of time slots defined by periods and offsets relating to slots and / or symbols. In another example, an SRS configuration time pattern may be characterized by a bitmap of a certain length and a time reference, such as the start of a symbol, slot, subframe, and / or frame, identified by a symbol number, slot number, subframe number, and frame number, respectively. The pattern may then be defined by a bitmap that starts at the time reference and then repeats. Figure 5 shows an example of a configuration time pattern.

[0094] The parameters defining the SRS configuration time patterns may be configured by the RRC or predefined. In one embodiment, the set of SRS configuration time patterns may be configured separately from the SRS resources. Alternatively, at least one SRS configuration time pattern may be configured as part of the SRS resource configuration. For example, at least one SRS configuration time pattern may be configured as a new “resource type”.

[0095] - Variable SRS properties for each transmission event In various embodiments, the WTRU may consist of an SRS configuration time pattern, and each SRS transmission opportunity in the SRS configuration time pattern may be associated with a respective (or different) SRS configuration, a respective (or different) SRS resource set configuration, and / or a respective (or different) SRS resource configuration.

[0096] In one embodiment, the WTRU may consist of two or more types of SRS configurations. For example, the WTRU may consist of two or more (different) types of SRS configurations, where a first type can be used for normal SRS operation, and a second type can be used when the WTRU is configured with an SRS time pattern.

[0097] In one embodiment, when each SRS transmission opportunity in an SRS configuration time pattern is associated with a different SRS resource set configuration, the resource type may be assumed to be aperiodic. In an example, the WTRU may assume or be configured with different usages (e.g., beamManagement, codebook, nonCodebook, and / or antennaSwitching) for each SRS transmission opportunity. For example, the WTRU may be configured to use a first transmission opportunity for beamManagement and a second transmission opportunity for antennaSwitching. In another example, for each configuration SRS resource set (or each SRS resource set configuration), the WTRU may use each (or different) SRS resource configuration according to the respective configuration SRS resource set for the SRS transmission opportunity in the configuration pattern (e.g., the SRS configuration time pattern).

[0098] In one embodiment, when each SRS transmission opportunity in an SRS configuration time pattern is composed of the same SRS resource set but associated with different SRS resource configurations, the WTRU can use different SRS resource properties for each SRS transmission opportunity.

[0099] In one example, a WTRU may consist of two or more types of SRS resource set configurations. For instance, a WTRU can consist of two or more (different) types of SRS resource set configurations, the first type which can be used for normal SRS operation, and the second type which can be used when the WTRU is configured with an SRS time pattern. In another example, a WTRU (configured with an SRS time pattern) may consist of two or more SRS resource configurations for each SRS resource set.

[0100] In one embodiment, each SRS transmit opportunity may be configured to have a different SRS resource configuration to employ different transmit properties. In one example, the WTRU can use a different number of SRS ports for each transmit opportunity. In another example, to support multiple TRPs or to increase transmit diversity, the WTRU can use different spatialRelationInfo (e.g., spatial filters, beams) for each transmit opportunity. Additionally or alternatively, the WTRU can use different cyclic shifts or sequences for each transmit event to randomize potential interference.

[0101] - Activation of SRS configuration time patterns In various embodiments, the SRS configuration time pattern can be in an activated or deactivated state. The WTRU may determine that the set of resources for possible SRS transmissions consists only of the set of activated SRS configuration time patterns. These solutions may allow the network to more dynamically modify SRS transmission opportunities for each UE and thus more efficiently modify MU-MIMO pairing candidates.

[0102] A WTRU can determine its state by receiving RRC, MAC, or DCI signaling. For example, a WTRU may receive a MAC control element indicating which of at least one SRS configuration time pattern is activated, for example, using a bitmap or at least one index for the SRS configuration time pattern. In one embodiment, a WTRU can determine a unique activated SRS configuration time pattern and any other SRS configuration time pattern is deactivated based on the index received from RRC, MAC, or DCI signaling. When the RRC reconfigures the set of SRS configuration time patterns, a WTRU can determine that the initial state of each pattern is activated or deactivated, either explicitly or implicitly, from the RRC signaling (e.g., all activated, all deactivated, or only the first one activated). When the bandwidth portion changes, a WTRU can implicitly determine that the state of each pattern is either activated or deactivated.

[0103] - Triggered SRS configuration time pattern In various embodiments, a WTRU may receive instructions (e.g., the first instructions) to transmit an SRS at a future time not included in the first instructions. Such instructions may be applicable to a particular set of SRS configuration time patterns, such as an activated set of SRS configuration time patterns, or a set explicitly included in the instructions. In this case, the WTRU may determine that such a set of SRS configuration time patterns may be in a “triggered” state. The WTRU may then transmit an SRS for several occasions for the SRS configuration time pattern, provided that it is in a triggered state. Such transmissions may occur following the receipt of a second instructions or another event (e.g., the start of a COT), as described below. After transmitting an SRS for a configuration time pattern, the WTRU may determine that such a pattern is in an “untriggered” state. The WTRU may also determine that a pattern is in an “untriggered” state when a bandwidth portion is changed or when a timer started when the pattern was set to an “triggered” state expires. When the RRC reconfigures or activates a set of SRS configuration time patterns, the WTRU can determine whether the initial state of each pattern is triggered or not.

[0104] - SRS transmission trigger A WTRU can transmit an SRS on at least one occasion defined by at least one SRS configuration time pattern, based on the following:

[0105] In one embodiment, the WTRU can be transmitted by the union of SRS configuration time patterns, or alternatively, by the union of activated SRS configuration time patterns, for all occasions defined by that union.

[0106] In one embodiment, the WTRU may be transmitted upon receipt of the DCI, following the start of the COT, or after successful access to the channel, in a subset of opportunities for the SRS configuration time pattern.

[0107] The following are shown in the DCI and may be signaled by MAC (e.g., MAC EC) or RRC messages, or may be predefined: 1) a set of SRS configuration time patterns on which SRS is transmitted; 2) the number of occasions on which SRS is transmitted for each pattern or set of patterns; and / or 3) the first occasion on which SRS is transmitted for each pattern or set of patterns. For example, such an occasion may be the Nth occasion following several symbols S following the last symbol of the PDCCH on which the DCI is decoded, where N and S are predefined or may be shown in the DCI.

[0108] In various embodiments, the set of SRS configuration time patterns may be limited to a subset of activated and / or triggered patterns.

[0109] - Instructions to send within Channel Occupancy Time (COT) In various embodiments, a WTRU can receive instructions to transmit an SRS in the current or next COT slot. For example, as shown in Figure 6, a WTRU can receive instructions via DCI or MAC CE to transmit an SRS in the next UL resource of the current COT. In another example, a WTRU can receive instructions to transmit an SRS in a specific (e.g., the first UL resource) UL resource of a subsequent or future COT. In this example, the WTRU does not necessarily need to receive further instructions to transmit an SRS, but can do so when it determines or is instructed that a subsequent or future COT has started.

[0110] A WTRU can receive instructions that it can send an SRS on a specific (e.g., first) UL resource of a COT acquired by a UE. In such cases, the WTRU can send an SRS on the UL resource once it has successfully acquired a channel and the COT acquired by the UE has started. In some cases, as shown in Figure 7, the gNB can recognize the specific timing when the WTRU will attempt to acquire a channel and start a COT (e.g., if the gNB allows a specific resource on which the WTRU can attempt to acquire a channel). In other cases, the WTRU can autonomously decide when to acquire a channel depending on whether it has data to send (e.g., on a configuration grant resource). Thus, the WTRU can indicate to the gNB when the transmission includes an SRS that was previously triggered. For example, the WTRU can receive a command to send an SRS on a specific UL resource of the next UE-acquired COT. The WTRU can only attempt to acquire a COT when it has data to send on a configuration grant. The WTRU can indicate to the gNB whether the WTRU-acquired COT includes an SRS transmission. WTRU can implicitly indicate to the gNB the presence of SRS in at least one of the following transmissions: standalone transmission, configured grant UCI (CG-UCI), or PUCCH transmission, via SRS parameters.

[0111] In one embodiment, upon receiving an instruction from the network (e.g., a gNB) to transmit an SRS, a WTRU can attempt to acquire a channel on the next appropriate CG resource, regardless of whether it has data to transmit. Therefore, if the WTRU successfully acquires a channel, it can transmit only the SRS on the CG resource.

[0112] In one embodiment, a WTRU may consist of SRS transmission opportunities (e.g., SRS configuration time patterns) as defined previously. Such opportunities may occur periodically and may be defined at specific timing instances (and possibly at specific frequency positions). Upon receiving an instruction to transmit an SRS on a future UL resource, the WTRU can transmit an SRS at the next SRS transmission opportunity. The WTRU may determine a suitable SRS transmission opportunity to transmit an SRS as one that satisfies the offset indicated by the gNB. For example, the WTRU may decide to transmit an SRS at a first SRS transmission opportunity that occurs after the time the instruction was received + the indicated offset timing. In another example, a WTRU might decide to transmit an SRS on an SRS transmission opportunity that occurs within a period that begins by the time the instruction is received and ends by the time indicated by the offset.

[0113] - Inter-WTRU coordination for transmitting SRS In various embodiments, a WTRU can obtain a COT (Conditional Occurrence Toll) and determine that the WTRU has resources to transmit an SRS and that it needs to transmit an SRS. For example, before transmitting an SRS, a WTRU may transmit a WTRU-to-WTRU (or UE-to-UE) instruction indicating that the following SRS transmission resources will be used to transmit the SRS. Other UEs may listen for such transmissions from neighboring UEs. Upon receiving an inter-UE instruction, the other UE may transmit an SRS using the same resources. This may enable multi-UE transmission of SRSs to support MU-MIMO in some cases.

[0114] - LBT for triggered SRS transmission In various embodiments, a WTRU may use a channel solely for transmitting SRS. In such cases, the WTRU may not need to perform channel access (e.g., Listen Before Talk (LBT)) before transmitting SRS. In other cases, if a WTRU has data to transmit on a resource adjacent to the SRS resource, the WTRU may perform channel access (e.g., LBT). The choice of LBT type to perform may depend on at least one of the following: the existence of data, the type of data, the timing of the UL transmission relative to the previous DL transmission (e.g., a gap), or instructions received by the WTRU.

[0115] - SRS transmission instruction In various embodiments, the WTRU may receive instructions to transmit an SRS in the current or subsequent COT. Such instructions may be received by the DCI or MAC CE. The instructions may reuse other control channel transmissions. For example, the WTRU may receive instructions to transmit an SRS in the DCI used to indicate that a COT is active. For example, the GC-PDCCH indicating an active COT may also be used to instruct the WTRU to transmit an SRS (possibly with a timing offset). The timing offset may be determined depending on the COT timing.

[0116] - Multiple timing offsets In various embodiments, the SRS transmission instruction may include or map to multiple timing offsets. The WTRU can determine a timing offset depending on at least one of the following: - Whether a channel is available for the intended SRS transmission time (e.g., whether an active COT exists). In this example, the WTRU can transmit the SRS using a first timing offset in which the channel is available for transmission. - Active COT parameters. For example, if a WTRU acquires a first set of unlicensed subbands for COT, the WTRU can use a first timing offset for SRS transmission. If a WTRU acquires a second set of unlicensed subbands for COT, the WTRU can use a second timing offset for SRS transmission. -The type of data that the WTRU needs to send (for example, depending on the contents of its buffer). For example, higher priority data may be associated with a first timing offset, and lower priority data may be associated with a second timing offset. - Whether the WTRU has data to transmit. - SRS transmission priority. For example, different SRS transmissions may be assigned different priorities.

[0117] Two-stage DCI instruction In various embodiments, a WTRU can transmit an SRS based on the reception of an SRS configuration trigger and (e.g., in combination) an SRS transmit trigger. In some examples, a two-stage DCI instruction mechanism may include using SRS configuration triggers and SRS transmit triggers in different downlink control channels (e.g., multiple DCIs or PDCCHs) for dynamic aperiodic SRS control and SRS transmission. In some cases, a two-stage DCI instruction mechanism can reduce PDCCH traffic overload.

[0118] Figure 8 shows an example of a two-stage DCI instruction mechanism. In the example, a WTRU can receive an SRS configuration trigger in a first DCI (e.g., a WTRU-specific DCI). A WTRU can receive an SRS transmission trigger in a second DCI (e.g., a group-common DCI). Each DCI may be received in its corresponding PDCCH. The PDCCH may be received in a UE-specific search space or a common search space (SS). In the example, the SRS configuration trigger may be received in the WTRU-specific SS, and the SRS transmission trigger may be received in the common SS. A WTRU may consist of an RNTI (e.g., a UE-specific RNTI or a group RNTI) that can be used for the SRS transmission trigger (e.g., it may be used specifically for that purpose). A WTRU may consist of an RNTI (e.g., a UE-specific RNTI or a group RNTI) that can be used for the SRS configuration trigger (e.g., it may be used specifically for that purpose). Cyclic redundancy check (CRC) of DCIs may be scrambled with the RNTIs described herein. WTRU can receive DCI using RNTI (for example, successfully decode DCI using RNTI).

[0119] In another example, a WTRU can receive one trigger at MAC-CE and the other trigger at DCI. For example, a WTRU can receive an SRS configuration trigger at MAC-CE. A WTRU can receive an SRS transmit trigger at DCI. In yet another example, a WTRU can receive each of the triggers at the corresponding MAC-CE (e.g., different MAC-CEs).

[0120] A WTRU may consist of one or more sets of resources that may be used for SRS transmission. A set of resources may include one or more resources in frequency and / or time (e.g., patterns of resources in frequency and / or time). A frequency resource may be or include one or more resource elements (REs), resource blocks (RBs), or physical RBs (PRBs). The configuration of the set of resources may identify frequency resources for SRS transmission (e.g., frequency positions) and / or time positions for SRS transmission. A time position may include, for example, the starting symbol, the number of symbols, which symbol in the duration of a slot, the number of slots, the symbol and / or the pattern of slots.

[0121] In various embodiments, resource sets (e.g., SRS resource sets) and sets of resources (e.g., SRS resources) may be used interchangeably as described herein.

[0122] In various embodiments, an SRS configuration trigger may identify one or more configured sets of SRS resources that may be used for SRS transmission. By identifying a set of SRS resources, the trigger may identify resources for SRS transmission at time and / or frequency (e.g., through the configuration of resource sets). The identified resources may reside in one or more slots.

[0123] In the example, a resource set may have an associated slot offset (for example, a resource set may consist of slot offsets). An SRS configuration trigger may indicate whether to use the associated (e.g., configured) slot offset or to ignore the slot offset and wait, for example, for an SRS transmit trigger to be sent. If the SRS configuration trigger indicates that a slot offset should be used, the WTRU can transmit an SRS with the indicated resource in the slot indicated by the slot offset. The slot offset may indicate an offset within a slot from the slot where the PDCCH (or MAC-CE) carrying the SRS configuration trigger is received. If the SRS configuration trigger indicates that no slot offset will be used, the WTRU does not need to transmit an SRS in response to receiving the SRS configuration trigger. The WTRU may transmit an SRS in response to receiving an SRS transmit trigger that may be received after the SRS configuration trigger.

[0124] In another example, a WTRU may not have to transmit an SRS in response to receiving an SRS configuration trigger. The WTRU can understand that the trigger is for configuration, not transmission, regardless of whether, for example, an SRS resource set is configured or associated with a slot offset.

[0125] In the example, an SRS resource set (e.g., an SRS resource set for use with a configuration trigger and a transmit trigger) does not have to be configured with a slot offset, or does not have to have an associated slot offset. A WTRU does not have to transmit an SRS in response to receiving an SRS configuration trigger. A WTRU may transmit an SRS in response to receiving an SRS transmit trigger, which may be received after the SRS configuration trigger.

[0126] An SRS transmit trigger may indicate one or more of the following: slot offset, number of slots, slot pattern, first slot, etc. An SRS transmit trigger may indicate one or more SRS time-related parameters. Time-related parameters may include slots, slot offset, start slot, number of slots, slot pattern, start symbol, number of symbols, symbol pattern, etc.

[0127] In the example, the WTRU can use an SRS configuration trigger to determine one or more (e.g., all) of the frequency-related parameters for an SRS transmit. The WTRU can use an SRS configuration trigger to determine at least some of the time-related parameters for an SRS transmit. The WTRU can use an SRS transmit trigger to determine at least some (e.g., some others) of the time-related SRS parameters.

[0128] The value of a time-related parameter indicated by a transmit trigger may override the value of a time-related parameter indicated by a configuration trigger. For example, a WTRU may receive an instruction for a first value of a time-related parameter via a configuration trigger. The WTRU may receive an instruction for a second value of a time-related parameter via a transmit trigger. The WTRU may use the second value of the time-related parameter, for example, when deciding when to transmit an SRS.

[0129] A WTRU can receive SRS configuration triggers in or with a UL Grant DCI or DL ​​Grant DCI. A WTRU can receive SRS transmit triggers in or with a UL Grant DCI or DL ​​Grant DCI.

[0130] A WTRU may receive an SRS transmit trigger in a DCI that does not include or is not used for UL grants or DL ​​grants. A WTRU may receive an SRS transmit trigger in a DCI that may be used to provide one or more of the following: a slot format indicator (SFI), a channel occupancy time (COT) indicator, and / or an SS switching indicator. The COT indicator may indicate the remaining time in the COT, for example, the COT obtained by a gNB. When a WTRU receives an SRS transmit trigger in a DCI that may be used to indicate an SFI, a COT indicator, and / or an SS switching indicator, one or more of the SFI, a COT indicator, and / or an SS switching indicator may or may not be present in the DCI.

[0131] A WTRU can transmit an SRS based on receiving an SRS transmit trigger or in response to an SRS transmit trigger. When a UE transmits an SRS based on receiving an SRS transmit trigger or in response to an SRS transmit trigger, the WTRU can transmit an SRS on a resource in a slot indicated by a slot offset. The offset may be an offset in a slot from the slot where the PDCCH (or MAC-CE) carrying the SRS transmit trigger is received. In the example, the slot offset used by the WTRU may be indicated by the SRS transmit trigger. The slot offset may be indicated directly by the transmit trigger. For example, the slot offset may be included in the DCI or MAC-CE providing the transmit trigger. The slot offset may be indicated by an index or other indicator provided by the transmit trigger (e.g., by the DCI or MAC-CE). The index or other indicator may indicate a configured value from a configured set of values ​​for the slot offset.

[0132] In the example, the slot offset used by the WTRU may be a configured slot offset. For example, the slot offset may be included in the configuration of the SRS resource set. A configuration trigger may indicate a resource set. A send trigger may indicate the use of a configured slot offset for a resource set (for example, using it for a send trigger).

[0133] In another example, an SRS resource set may have a set of slot offsets configured for the SRS resource set. A transmit trigger may indicate which slot offset to use. If only one slot offset is configured for a resource set, then (for example, when that resource set is indicated) no instruction on which one to use is required, used, and / or provided.

[0134] A WTRU can transmit SRS based on, or using, time resources, time-related parameters, and / or frequency resources indicated by a combination of configuration triggers and transmit triggers. For example, a WTRU can transmit on indicated frequency resources. A WTRU can transmit on symbols and slots based on indicated time-related parameters. A WTRU can transmit, for example, on indicated time-related parameters, on one or more symbols, one or more slots, and / or sets or patterns of symbols and / or slots.

[0135] One or more WTRUs can receive individual SRS configuration triggers. SRS transmit triggers that may indicate a slot offset can be received by one or more WTRUs. One or more WTRUs can use the received slot offset to transmit an SRS in the same slot. One or more WTRUs can transmit an SRS according to the resources and transmit parameters indicated by their respective configuration triggers.

[0136] SRS transmit parameters (e.g., including time and / or frequency resources, or otherwise) may be provided by configuration triggers and / or transmit triggers. The WTRU can transmit the SRS according to the received transmit parameters. Transmit parameters indicated by a transmit trigger may override transmit parameters indicated by a configuration trigger.

[0137] An SRS resource set may include (for example, consist of) trigger mode instructions. Trigger mode instructions may indicate when or on what trigger to use one or more parameters, such as time-related parameters for transmitting an SRS. The trigger mode may be indicated by an SRS resource set, which may be indicated by an SRS configuration trigger and / or SRS transmit trigger received by the WTRU.

[0138] For example, a trigger mode instruction may indicate whether a configured slot offset and / or one or more other parameters (e.g., time-related parameters) should be used when a request indicating a configured trigger or resource set is received. The WTRU can use the trigger mode instruction configured for a resource set to determine, for example, when to send an SRS (e.g., for or in response to any SRS trigger or request) according to the SRS resource set.

[0139] For example, in the first trigger mode, the WTRU may transmit an SRS in response to an SRS configuration trigger or SRS request or trigger received in the UL or DL ​​grant. In the second trigger mode, the WTRU does not have to transmit an SRS in response to an SRS configuration trigger or SRS request or trigger received in the UL or DL ​​grant. In the second trigger mode, the WTRU may transmit an SRS in response to an SRS transmit trigger that may occur after the SRS configuration trigger. In the second trigger mode, the WTRU may transmit an SRS in response to an SRS transmit trigger or SRS request or trigger that is not received with the UL or DL ​​grant.

[0140] An SRS transmission may be considered a pending SRS transmission following the reception of an SRS configuration trigger. An SRS configuration trigger or a pending SRS transmission may be canceled or expire after its expiration time.

[0141] For example, if a WTRU can receive an SRS configuration trigger in the first slot and does not receive transmit triggers for any slots exceeding a threshold number, the WTRU can cancel the SRS transmit associated with the SRS configuration trigger. If a WTRU receives an SRS transmit trigger and has no pending SRS transmits (e.g., based on an unexpired SRS configuration trigger), the WTRU can ignore the SRS transmit trigger. The number of slots is just an example. Different time units, such as symbols or milliseconds, may be used for the expiration time and / or threshold.

[0142] In various embodiments, thresholds can be configured. The configuration of thresholds may be included in the configuration of the SRS resource set.

[0143] An SRS transmit trigger may be used when an SRS configuration trigger is received within a configured number of slots or configured time periods prior to the reception of the SRS transmit trigger. If a WTRU can receive an SRS transmit trigger (for example, in a slot) and the WTRU has not received an SRS configuration trigger within some slots or within a time period or window prior to the SRS transmit trigger, the WTRU may ignore the SRS transmit trigger. For example, a WTRU does not have to transmit an SRS based on or in response to a transmit trigger. The number of slots or time periods may be a configured threshold number of slots or a configured threshold time period. The number of slots or time periods may be a configured window of slots or a configured time window.

[0144] In various embodiments, thresholds (e.g., slot or time thresholds), or slot windows, or time (e.g., in milliseconds) may be configured via at least one of an SRS configuration trigger, an SRS transmission trigger, an SRS resource set, and / or a separate configuration. Time and time quantities may be used interchangeably.

[0145] Mode selection for SU / MU-MIMO - Operation Mode In various embodiments, one or more operating modes may be used, defined, or configured for aperiodic SRS triggering based on aperiodic SRS trigger offset determination, where the aperiodic SRS trigger offset may be an offset between a first slot from which a WTRU can receive an SRS trigger instruction and a second slot from which a WTRU can send or transmit a triggered SRS resource and / or resource set. Hereafter, the aperiodic SRS trigger offset may be interchangeably referred to as the SRS offset, slot offset (or slotOffset), and / or trigger offset.

[0146] In operation mode, SRS offsets may be determined, used, or selected in a semi-static manner. For example, an SRS offset may be configured for each SRS resource set or SRS resource, and the associated SRS offset may be used or determined when the SRS resource set or SRS resource is triggered. In various embodiments, a set of SRS offset values ​​may be predefined or configured, and one SRS offset value in the set may be selected, used, or configured for an SRS resource set or SRS resource. In the example, one or more SRS resources may be associated with an SRS resource set. An SRS offset may be configured or determined for the SRS resource set, and one or more SRS resources associated with the SRS resource set may use the SRS offset value configured for the associated SRS resource set.

[0147] In operating mode, SRS offsets may be determined, used, selected, or indicated in a dynamic manner. For example, the SRS offset for a triggered SRS resource (or set of SRS resources) may be determined dynamically based on an instruction. One or more of the following may apply: (1) The SRS offset instruction may be signaled with associated control information (e.g., downlink control information or sidelink control information); and / or (2) The SRS offset instruction may be a delta offset from a configured SRS offset for the SRS resource (or set of SRS resources).

[0148] In operating mode, the SRS offset may be implicitly determined based on one or more system and / or UE-specific parameters, which may include at least one of the following: identification information (e.g., cell ID, UE-ID, BWP-ID), system configuration (e.g., subcarrier spacing, TDD UL / DL configuration, number of carriers, etc.), and scheduling parameters (e.g., MCS, scheduled bandwidth, configured or indicated DM-RS pattern, etc.).

[0149] - Determining the operating mode In one embodiment, the operating mode for an SRS trigger (e.g., SRS trigger mode) may be determined based on the uplink transmit mode used, selected, or determined. In various embodiments, the SRS trigger mode may be used to distinguish between different modes of uplink transmit, for example, single-user (SU) mode and multi-user (MU) mode of uplink transmit. In the example, the operating mode for an SRS trigger may be applied in the scheme described herein, depending on the SU / MU operating mode. For example, the uplink transmit mode (e.g., SU / MU mode of uplink transmit) or the SRS trigger mode may be determined based on one or more of the following: ● The DCI format used for SRS triggering. For example, a first SRS trigger mode may be used when an SRS transmission is triggered by a first DCI format (e.g., DCI format 0_1), and a second SRS trigger mode may be used when an SRS transmission is triggered by a second DCI format (e.g., DCI format 1_1). ● The number of DM-RS CDM groups for which no data is provided. For example, an SRS transmission is triggered in a DCI (e.g., DCI format 0_1) where the number of DMRS CDM groups without data is greater than the threshold. ○Thresholds may vary based on the DMRS type, the number of layers, and / or the number of codewords. ●The configured DMRS type. For example, a first SRS trigger mode may be used when the first DMRS type is configured for UL transmission in BWP (e.g., DMRS type-1), and a second SRS trigger mode may be used when the second DMRS type is configured for UE transmission in BWP (e.g., DMRS type-2). ●Configured DMRS density. For example, the first SRS trigger mode may be used when the DMRS density (e.g., time density) is below a threshold, and the second SRS trigger mode may be used when the DM-RS density is above a threshold. ○The DMRS density in this specification may be the number of DMRS symbols in a slot. ● The maximum number of MIMO layers configured. For example, the first SRS trigger mode may be used when the maximum number of MIMO layers configured for BWP is less than the threshold, and the second SRS trigger mode may be used when the maximum number of MIMO layers configured for BWP is equal to or greater than the threshold.

[0150] In one embodiment, the SRS trigger mode may be determined based on the configuration of the bandwidth portion (BWP). For example, a first SRS trigger mode may be configured, used, or determined for a first BWP, and a second SRS trigger mode may be configured, used, or determined for a second BWP. In some examples, the SRS trigger mode may be determined based on any of the associated BWP-id, the number of configured SRS resources and / or SRS resource sets, the number of SRS antenna ports (e.g., maximum), and the SRS configuration for the BWP.

[0151] In one embodiment, the SRS trigger mode may be determined based on the identification information of the relevant search space and / or coreset. For example, the SRS trigger mode may be determined based on which search space and / or coreset the WTRU received an SRS trigger. If the UE receives an SRS trigger (e.g., first search space identification information or coreset identification information) in a first search space and / or coreset, the WTRU may use or determine the first SRS trigger mode, and if the WTRU receives an SRS trigger (e.g., second search space identification information or coreset identification information) in a second search space and / or coreset, the WTRU may use or determine the second SRS trigger mode. In some cases, the SRS trigger mode may be configured for a search space and / or coreset.

[0152] In one embodiment, the SRS trigger mode may be determined based on the number of bits configured for the SRS request field in the DCI. For example, if the number of bits for the SRS request field in the DCI is 2 bits or less, a first SRS trigger mode may be used or determined; otherwise, a second SRS trigger mode may be used. In some examples, when the SRS request bit field has more than 2 bits, the first 2 bits may be used to indicate the set of triggered SRS resources, and the remaining bits may be used to indicate the SRS trigger offset value.

[0153] Extended nonperiodic SRS transmission In various embodiments, the WTRU may be indicated (or instructed) or configured to operate in one or more modes of aperiodic SRS transmission, e.g., legacy mode (e.g., the first mode in Figure 9) and / or extended mode (e.g., the second mode in Figure 9). In some examples, the WTRU may be semi-statically or dynamically configured to operate in one of the modes of aperiodic SRS transmission. For example, in dynamic operation, the WTRU may be explicitly indicated to operate in extended mode by L1 signaling to the WTRU (e.g., by DCI). Additionally or alternatively, the WTRU may implicitly determine its mode of aperiodic SRS transmission.

[0154] In the example, referring to Figure 9, a mechanism / procedure for mode determination for aperiodic SRS transmission is provided. In this example, the WTRU can determine or select an operating mode (or mechanism / procedure) for aperiodic SRS transmission based on (or using) explicit or implicit information.

[0155] In one embodiment, for an SRS transmission (e.g., aperiodic SRS transmission), the WTRU may receive an SRS configuration of one or more SRS resource sets, each SRS resource set associated with a set of slot offsets and / or slot offset deltas. The WTRU may receive an SRS request / instruction in the DCI, where the SRS request may indicate an SRS resource set from one or more SRS resource sets. The WTRU may determine a mode (or scheme) for an SRS transmission based, for example, on any combination of 1) the search space or CORESET from which the DCI is received, 2) the DCI format, 3) the instructions within the DCI, and / or 4) the RNTI used to scramble the DCI CRC.

[0156] In one example, if the WTRU decides to use a first SRS mode (e.g., legacy mode, or the first mode in Figure 9), the WTRU can determine (or select) one or more slots for SRS transmission based on (or using) the slot offsets associated with each SRS resource set. In another example, if the WTRU decides to use a second SRS mode (e.g., extended mode, or the second mode in Figure 9), the WTRU can determine (or select) at least one slot offset delta from the set of slot offset deltas associated with each SRS resource set. In some cases, the WTRU can determine (or select) at least one slot offset delta based on received instructions (e.g., in the DCI, another DCI, or MAC CE described above) or determined information (e.g., from an RNTI, such as an RNTI used to scramble DCI CRCs). The WTRU can determine a slot for SRS transmission based on (or using) the slot offsets (associated with the SRS resource sets) and the determined slot offset deltas. A WTRU can transmit SRS on one or more resources in the SRS resource set within a determined slot.

[0157] Various embodiments disclose methods, apparatus, and / or systems for flexible nonperiodic RS (e.g., SRS) transmission in wireless communication. In one embodiment, a method for wireless communication (e.g., implemented in WTRU 102) includes receiving configuration information for one or more SRS resource sets, each SRS resource set of one or more SRS resource sets associated with a set of slot offsets and slot offset deltas; receiving a DCI indicating an SRS request indicating an SRS resource set among the one or more SRS resource sets; determining an SRS configuration from a set of SRS configurations for SRS transmission; determining a slot for transmitting an SRS based on the determined SRS configuration; and transmitting an SRS in the determined slot using the resources of the indicated SRS resource set.

[0158] In one embodiment, the SRS configuration is determined from a set of SRS configurations for SRS transmission based on one of the following: 1) the search space or CORESET in which the DCI is received, 2) the DCI format, 3) the instructions in the DCI, and / or 4) the Radio Network Temporary Identifier (RNTI) used to scramble the Cyclic Redundancy Check (CRC) for the DCI. In the example, the slot for transmitting the SRS is determined based on the slot offset associated with the indicated SRS resource set.

[0159] In one embodiment, the method may also include determining a slot offset delta from a set of slot offset deltas associated with a given SRS resource set, and the slot for transmitting an SRS is determined based on 1) a slot offset associated with the given SRS resource set and 2) the determined slot offset delta. In an example, the slot offset delta is determined from a set of slot offset deltas based on any of the following: 1) received configuration information, 2) received DCI, 3) determined SRS configuration, 4) search space or CORESET from which the DCI is received, 5) DCI format, 6) instructions in the DCI, 7) RNTI used to scramble cyclic redundancy check (CRC) for the DCI, or 8) MAC CE. In one embodiment, the slot for transmitting an SRS is determined based on a slot offset associated with an SRS resource set and the determined slot offset delta. In one embodiment, configuration information for one or more SRS resource sets is received via radio resource control (RRC) signaling.

[0160] In one embodiment, a method for wireless communication (for example, implemented in WTRU 102) includes receiving a first SRS configuration including first slot information, receiving a second SRS configuration including second slot information, and determining a slot index for SRS transmission based on the first and second slot information. The method may also include transmitting aperiodic SRS using a determined slot index. In the example, the first slot information includes a slot offset value. In the example, the second slot information includes one or more delta offset values, the one or more delta offset values ​​being used to compensate for the slot offset value. In the example, the method may include combining the slot offset value and one or more delta offset values. In the example, the second SRS configuration is received via DCI or MAC CE. In the example, the first SRS configuration and at least one of the second SRS configurations are Radio Resource Control (RRC) configurations.

[0161] In one embodiment, a method for wireless communication (e.g., implemented in WTRU 102) includes receiving a set of parameters for an SRS resource set, determining that an aperiodic SRS transmission is triggered based on a DCI, and transmitting an aperiodic SRS based on the set of parameters. In the example, the aperiodic SRS transmission is triggered by a WTRU-specific DCI, a group-common DCI, or an uplink DCI. In one embodiment, the method may include determining one or more slot offsets for an SRS resource set. In the example, one or more slot offsets are determined based on one or more DCI formats.

[0162] In one embodiment, a method for wireless communication (for example, implemented in WTRU 102) includes receiving an instruction to trigger a periodic RS transmission; determining a slot and a new slot format for a periodic RS transmission, wherein the new slot format indicates a different slot format used for the slot; and transmitting a periodic RS in the slot using the new slot format.

[0163] Slot formatting instructions for non-periodic SRS transmission In NR, for TDD operation, the WTRU may be configured (e.g., by a higher layer) to operate with a specific pattern of uplink (UL), downlink (DL), and / or flexible (F) slots, and / or a specific pattern of UL, DL, and flexible (F) symbols per slot. For example, the RRC parameter tdd-UL-DL-ConfigurationCommon provides a common pattern of slots within a pre-configured period.

[0164] In various embodiments, the WTRU may further provide the parameter tdd-UL-DL-ConfigurationDedicated to override flexible (F) symbols per slot over the number of slots indicated by tdd-UL-DL-ConfigurationCommon. For a set of symbols for slots indicated as flexible by tdd-UL-DL-ConfigurationCommon or tdd-UL-DL-ConfigurationDedicated, the WTRU may receive a DCI format 2_0 having an SFI index field value that may indicate a new slot format [2].

[0165] In various embodiments, the WTRU may be configured to operate in SFI_aperiodic mode. When SFI_aperiodic mode is configured, for example, when the WTRU receives an L1 or L2 command that triggers aperiodic RS signal transmission, the received information element (IE) may also serve as a slot format indicator. In the example, the slot format indicator may be used to indicate / determine a change in format. For example, the WTRU can change the slot format indicated for aperiodic RS transmission to another slot format required for RS transmission, based on the information provided by the slot format indicator.

[0166] In one embodiment, if the slot indicated for UL (or DL) aperiodic RS transmission is already a UL (or DL) slot, the slot format indicated by IE may be F-type only, and the indicated slot format (e.g., F-type) has a configuration of UL, DL, and / or F symbols.

[0167] In one embodiment, if the slot indicated for aperiodic RS transmission is a UL slot, the indicated slot type may also be DL or F, and the newly indicated DL or F slot format may override the previous slot type and replace it with a new configuration of UL, DL, and / or F symbols. In another example, if the slot indicated for aperiodic RS transmission is a DL slot, the indicated slot type may also be UL or F, and the newly indicated UL or F slot format may override the previous slot type and replace it with a new configuration of UL, DL, and / or F symbols.

[0168] In one embodiment, if the slot indicated for aperiodic SRS transmission is an F slot, the indicated slot type may be DL, UL, or F type (e.g., a new F type), and the newly indicated DL, UL, or F slot format may override the previous slot type and replace it with a new configuration of UL, DL, and / or F symbols. For example, a WTRU may determine that the slot indicated for aperiodic SRS transmission is an F slot having a first F slot type, and the WTRU may determine that the indicated slot format is a DL slot type, a UL slot type, or a new F slot type (e.g., a second F slot type different from the first F slot type), and the newly indicated DL, UL, or F slot format / type (e.g., a new configuration of UL, DL, and / or F symbols) may be used for the slot indicated for aperiodic SRS transmission.

[0169] In various embodiments, the WTRU may be configured to operate in SFI_Aperiodic Mode. In the example, when SFI_Aperiodic Mode is configured, when the WTRU receives a DCI that triggers an aperiodic SRS transmission, the received DCI may also serve as a slot format indicator. In the example, the slot format indicator may be used to indicate / determine a change in format. For example, based on the information provided by the slot format indicator, the WTRU may change the format of a slot indicated for an aperiodic SRS transmission to a different slot format suitable for SRS transmission. Thus, the WTRU may not need to receive a separate DCI format (e.g., DCI format 2_0) to adapt a slot indicated for SRS transmission to a slot with a UL transmission opportunity.

[0170] In one embodiment, if the slot indicated for aperiodic SRS transmission is already a UL slot, the slot format indicated by IE may be F-type only, and the indicated slot format (e.g., F-type) has a configuration of UL, DL, and / or F symbols.

[0171] In one embodiment, if the slot indicated for aperiodic RS transmission is a UL slot, the indicated slot type may also be DL or F, and the newly indicated DL or F slot format may override the previous slot type and replace it with a new configuration of UL, DL, and / or F symbols. In another example, if the slot indicated for aperiodic RS transmission is a DL slot, the indicated slot type may also be UL or F, and the newly indicated UL or F slot format may override the previous slot type and replace it with a new configuration of UL, DL, and / or F symbols.

[0172] In one embodiment, if the slot indicated for aperiodic SRS transmission is an F slot, the indicated slot type may be DL, UL, or F type (e.g., a new F type), and the newly indicated DL, UL, or F slot format may override the previous slot type and replace it with a new configuration of UL, DL, and / or F symbols. For example, a WTRU may determine that the slot indicated for aperiodic SRS transmission is an F slot having a first F slot type, and the WTRU may determine that the indicated slot format is a DL slot type, a UL slot type, or a new F slot type (e.g., a second F slot type different from the first F slot type), and the newly indicated DL, UL, or F slot format / type (e.g., a new configuration of UL, DL, and / or F symbols) may be used for the slot indicated for aperiodic SRS transmission.

[0173] In various embodiments, the IE that triggers the aperiodic RS transmission may carry a field indicating a specific slot format (e.g., an SFI index). In one embodiment, to reduce the overhead associated with the IE, instead of the SFI index, the WTRU may receive a new index (e.g., SFI_index_aperiodic) which may have a smaller size than the SFI index. In the example, the new index (e.g., SFI_index_aperiodic) may select only a subset of slot format options from the original SFI table (e.g., shown in reference [2]).

[0174] In another embodiment, the WTRU may be configured with one or more specific slot formats for aperiodic RS transmissions (e.g., by a higher layer), each configured slot format may correspond to a preferred slot format for transmission, e.g., UL, DL, or F. Thus, when the WTRU receives an IE that triggers aperiodic RS transmission, the WTRU can use a specific slot format configured by a higher layer.

[0175] Figure 10 shows an example of configuring a slot format instruction by triggering a DCI for aperiodic SRS transmission. In some cases, even if a slot indicated for an SRS transmission is a flexible (F) slot with some symbols allocated for UL transmissions, the indicated slot may still not have enough symbols to accommodate an SRS transmission. To accommodate an SRS transmission, the WTRU can receive, determine, or configure a slot format instruction by triggering a DCI for aperiodic SRS transmissions. Referring to Figure 10, in an example as shown in Figure 10(a), triggering a DCI can change the slot type (e.g., from an F type with fewer UL symbols) to a full UL slot (e.g., with only UL symbols). In another example, as shown in Figure 10(b), triggering a DCI can change the slot format (e.g., a flexible format with fewer UL symbols) to another flexible format with more UL symbols.

[0176] While the features and elements are described above in specific combinations, those skilled in the art will understand that each feature or element can be used individually or in any combination with other features and elements. Furthermore, the methods described herein can be implemented in computer programs, software, or firmware embedded in computer-readable media for execution by a computer or processor. Examples of non-temporary computer-readable storage media include, but are not limited to, read-only memory (ROM), random access memory (RAM), registers, cache memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magneto-optical media, and optical media such as CD-ROM disks and digital multipurpose disks (DVDs). A processor associated with software can be used to implement a radio frequency transceiver for use in a WTRU102, UE, terminal, base station, RNC, or any host computer.

[0177] Furthermore, the embodiments described above include other devices, including processing platforms, computing systems, controllers, and processors. These devices may include at least one central processing unit ("CPU") and memory. According to the convention of those skilled in the art in the field of computer programming, references to operations and symbolic representations of arithmetic or instructions may be performed by various CPUs and memories. Such operations and arithmetic or instructions may be referred to as "executed," "executed by the computer," or "executed by the CPU."

[0178] Those skilled in the art will understand that operations and symbolically represented arithmetic or instructions involve the manipulation of electrical signals by the CPU. The electrical system represents data bits that can cause a resulting transformation or reduction of electrical signals, and maintains these data bits in memory locations of the memory system, thereby reconfiguring or otherwise modifying the CPU's operations and processing of other signals. The memory locations where the data bits are maintained are physical locations having specific electrical, magnetic, optical, or organic properties that correspond to or represent the data bits. It should be understood that typical embodiments are not limited to the platforms or CPUs described above, and other platforms and CPUs may support the methods provided.

[0179] Data bits may also be maintained on computer-readable media, including magnetic disks, optical disks, and any other volatile (e.g., Random Access Memory ("RAM")) or non-volatile (e.g., Read-Only Memory ("ROM")) mass storage systems readable by the CPU. The computer-readable media may include cooperative or interconnected computer-readable media distributed among multiple interconnected processing systems, which may reside exclusively on a processing system or be local or remote to the processing system. Typical embodiments are not limited to the memory described above, and it is understood that other platforms and memories may support the methods described.

[0180] In exemplary embodiments, any of the operations, processes, etc., described herein may be implemented as computer-readable instructions stored on a computer-readable medium. Computer-readable instructions can be executed by processors in mobile devices, network elements, and / or any other computing devices.

[0181] There is little distinction between hardware and software implementations of a system configuration. The use of hardware or software is generally a design choice representing a cost-effectiveness trade-off (for example, in the sense that, though not always, the choice between hardware and software can be important in certain contexts). There may be various vehicles (e.g., hardware, software, and / or firmware) that may affect the processes and / or systems and / or other technologies described herein, and the preferred vehicle may vary depending on the context in which the processes and / or systems and / or other technologies are deployed. For example, if the implementer determines that speed and accuracy are paramount, the implementer may choose a vehicle that is primarily hardware and / or firmware. If flexibility is paramount, the implementer may choose a vehicle that is primarily software. Alternatively, the implementer may choose any combination of hardware, software, and / or firmware.

[0182] The detailed description above illustrates various embodiments of devices and / or processes through the use of block diagrams, flowcharts, and / or examples. Those skilled in the art will understand that, insofar as such block diagrams, flowcharts, and / or examples include one or more functions and / or operations, each function and / or operation in such block diagrams, flowcharts, or examples may be implemented individually and / or collectively by a wide range of hardware, software, firmware, or substantially any combination thereof. Suitable processors include, by example, general-purpose processors, dedicated processors, conventional processors, digital signal processors (DSPs), multiple microprocessors, one or more microprocessors associated with a DSP core, controllers, microcontrollers, application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), field-programmable gate array (FPGA) circuits, any other type of integrated circuit (IC), and / or state machines.

[0183] While the features and elements are provided above in specific combinations, those skilled in the art will understand that each feature or element can be used individually or in any combination with other features and elements. This disclosure is not limited in terms of the specific embodiments described in this application, which are intended to be illustrative of various aspects. As will be apparent to those skilled in the art, many modifications and variations can be made without departing from the spirit and scope of the invention. Any elements, actions, or instructions used in the description of this application should not be construed as important or essential to the invention unless expressly presented as such. In addition to those enumerated herein, functionally equivalent methods and apparatus within the scope of this disclosure will be apparent to those skilled in the art from the above description. Such modifications and variations are intended to fall within the scope of the appended claims. This disclosure is limited only by the terms of the appended claims, and is limited to the full scope of the equivalents to which such claims are entitled. It should be understood that this disclosure is not limited to any particular method or system.

[0184] It should also be understood that the terms used herein are for the purpose of describing only specific embodiments and are not intended to limit them. Where used herein, and referred to herein, “Station” and its abbreviation “STA,” “User Equipment” and its abbreviation “UE” may mean or include: (i) a radio transmit and / or receive unit (WTRU), such as the infrastructure described herein; (ii) any of several embodiments of a WTRU, such as the infrastructure described herein; (iii) a radio-enabled and / or wired (e.g., tetherable) device configured to have some or all of the structure and functions of an exemplary WTRU (e.g., the infrastructure described herein); (iii) a radio-enabled and / or wired device configured to have less than all of the structure and functions of a described WTRU (e.g., the infrastructure described herein); or (iv) other. Details of exemplary WTRUs that may represent any UE enumerated herein are provided below with respect to Figures 1A to 1D.

[0185] In certain representative embodiments, some parts of the subject matter described herein may be implemented via application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), digital signal processors (DSPs), and / or other integrated formats. However, it will be recognized by those skilled in the art that some aspects of the embodiments disclosed herein can be equivalently implemented in an integrated circuit as one or more computer programs running on one or more computers (e.g., as one or more programs running on one or more computer systems), as one or more programs running on one or more processors (e.g., as one or more programs running on one or more microprocessors), as firmware, or substantially any combination thereof, and that designing circuits and / or writing software and / or firmware code is within the scope of the art of those skilled in the art in light of this disclosure. Furthermore, it will be understood by those skilled in the art that mechanisms of the subject matter described herein may be distributed as various forms of program products, and that exemplary embodiments of the subject matter described herein are applicable regardless of the particular type of signal-carrying medium used to actually carry out the distribution. Examples of signal-carrying media include, but are not limited to, recordable media such as floppy disks, hard disk drives, CDs, DVDs, digital tapes, and computer memory, as well as transmission media such as digital and / or analog communication media (e.g., optical fiber cables, waveguides, wired communication links, wireless communication links, etc.).

[0186] The subject matter described herein may, in some cases, depict different components that are contained within or connected to other different components. Such illustrated architectures are merely examples, and it should be understood that in practice, many other architectures can be implemented to achieve the same function. Conceptually, any arrangement of components to achieve the same function is effectively “associated” in such a way that the desired function can be achieved. Therefore, any two components combined herein to achieve a particular function, regardless of architecture or intermediate components, can be seen as “associated” with each other in such a way that the desired function can be achieved. Similarly, any two components thus associated can be considered “operably connected” or “operably coupled” with each other to achieve the desired function, and any two components that can be associated in such a way can be considered “operably coupled” with each other to achieve the desired function. Specific examples of operably coupled components include, but are not limited to, physically matable and / or physically interacting components, and / or wirelessly interactable and / or wirelessly interacting components, and / or logically interacting and / or logically interactable components.

[0187] With regard to the use of substantially any plural and / or singular terms herein, those skilled in the art can convert from plural to singular and / or singular to plural as appropriate to the context and / or use. For clarity purposes, various singular / plural rearrangements may be explicitly described herein.

[0188] In general, it will be understood by those skilled in the art that the terms used herein, and in particular in the appended claims (e.g., in the body of the appended claims), are generally intended to be “open” terms (for example, the term “contains” should be interpreted as “contains but not limited to,” the term “has” should be interpreted as “has at least,” and the term “contains” should be interpreted as “contains but not limited to.”). Furthermore, it will be understood by those skilled in the art that if a particular number of claims introduced are intended to be described, such intent is explicitly stated in the claim, and if such statement is not present, such intent does not exist. For example, if only one item is intended, the term “single” or similar wording may be used. To aid understanding, the following appended claims and / or descriptions herein may include the use of the introductory phrases “at least one” and “one or more” to introduce the description of a claim. However, the use of such phrases should not be interpreted as meaning that the introduction of a claim description by the indefinite article "a" or "an" limits any particular claim containing such introduced description to embodiments containing only one such description, even if the same claim contains the introductory phrase "one or more" or "at least one" and an indefinite article such as "a" or "an" (for example, "a" and / or "an" should be interpreted as meaning "at least one" or "one or more"). The same applies to the use of the definite article used to introduce a claim description. Furthermore, even if a particular number of descriptions in an introduced claim are explicitly stated, it will be recognized by those skilled in the art that such a statement should be interpreted as meaning at least the number stated (for example, the simple statement "two descriptions" without other modifiers means at least two descriptions or two or more descriptions).

[0189] Furthermore, when similar notation to "at least one of A, B, and C" is used, such structure is generally intended to mean what a person skilled in the art would understand (for example, "a system having at least one of A, B, and C" includes, but is not limited to, systems having A only, B only, C only, A and B together, A and C together, B and C together, and / or A, B, and C together). Where a notation similar to “at least one of A, B, or C” is used, such a structure is generally intended to mean what a person skilled in the art would understand (for example, “a system having at least one of A, B, or C” includes, but is not limited to, systems having A only, B only, C only, A and B together, A and C together, B and C together, and / or A, B, and C together). It will further be understood by a person skilled in the art that any substantially any disjunct word and / or phrase presenting two or more alternative terms in any description, claim, or drawing should be understood as intending to include the possibility of including one of the terms, either of the terms, or both of the terms. For example, the phrase “A or B” should be understood to include the possibility of “A” or “B” or “A and B”. Furthermore, as used herein, the term “any of” followed by a list of items and / or a list of categories of items is intended to include, any of, any combination of, any multiple of, and / or any multiple combination of items and / or categories of items, individually or in combination with other items and / or categories of items. Furthermore, as used herein, the terms “set / group” or “cluster” are intended to include any number of items, including zero. Furthermore, as used herein, the term “number” is intended to include any number, including zero.

[0190] In addition, if any feature or aspect of the present disclosure is described from the perspective of the Markush group, a person skilled in the art will recognize that the present disclosure is also described from the perspective of any individual member or subgroup of a member of the Markush group.

[0191] For all purposes, including providing written explanations, as will be understood by those skilled in the art, all scopes disclosed herein also encompass all possible subscopes and combinations thereof. Any enumerated scope can be readily recognized as making it readily possible and readily explain that the same scope can be broken down into at least equal 1 / 2, 1 / 3, 1 / 4, 1 / 5, 1 / 10, etc. As a non-limiting example, each scope described herein can readily be broken down into the lower third, the middle third, the upper third, etc. Also, as will be understood by those skilled in the art, all words such as “up to,” “at least,” “greater than,” and “less than” include the number mentioned and mean a scope that can be further broken down into subscopes as described above. Finally, as will be understood by those skilled in the art, a scope includes individual elements. Thus, for example, a group having 1 to 3 cells refers to a group having 1, 2, or 3 cells. Similarly, a group having 1 to 5 cells refers to a group having 1, 2, 3, 4, or 5 cells, and so on.

[0192] Furthermore, unless otherwise specifically stated, the claims should not be read as being limited to the order or elements provided. Moreover, in any claim, the use of the term “means for” is intended to appeal to Section 112, paragraph 6 of the U.S. Patent Act, or the means-plus-function claim format, and no claim without the term “means for” is intended to appeal in that way.

[0193] A radio frequency transceiver can be implemented using a software-associated processor for use in a radio transceiver unit (WTRU), user equipment (UE), terminal, base station, mobility management entity (MME), or evolved packet core (EPC), or any host computer. The WTRU may be used in conjunction with hardware and / or software-implemented modules such as software-defined radio (SDR), and may also be implemented in other components such as cameras, video camera modules, video phones, speakerphones, vibration devices, speakers, microphones, television transceivers, hands-free headsets, keyboards, Bluetooth® modules, frequency modulation (FM) radio units, near-field communication (NFC) modules, LCD display units, organic light-emitting diode (OLED) display units, digital music players, media players, video game player modules, internet browsers, and / or wireless local area network (WLAN) or ultra-wideband (UWB) modules.

[0194] Although the present invention has been described in relation to a communication system, it is intended that the system may be implemented in software on a microprocessor / general-purpose computer (not shown). In certain embodiments, one or more functions of various components may be implemented in software that controls a general-purpose computer.

[0195] In addition, although the present invention is illustrated and described herein with reference to specific embodiments, it is not intended to be limited to the details shown. Rather, various modifications can be made in detail within the scope of the claims and their equivalents without departing from the present invention.

[0196] Through this disclosure, those skilled in the art will understand that certain representative embodiments may be used as alternatives or in combination with other representative embodiments.

[0197] While the features and elements are described above in specific combinations, those skilled in the art will understand that each feature or element can be used individually or in any combination with other features and elements. Furthermore, the methods described herein can be implemented in computer programs, software, or firmware embedded in computer-readable media for execution by a computer or processor. Examples of non-temporary computer-readable storage media include, but are not limited to, read-only memory (ROM), random access memory (RAM), registers, cache memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magneto-optical media, and optical media such as CD-ROM disks and digital multi-purpose disks (DVDs). A processor associated with the software can be used to implement a radio frequency transceiver for use in a WRTU, UE, terminal, base station, RNC, or any host computer.

[0198] Furthermore, the embodiments described above include other devices, including processing platforms, computing systems, controllers, and processors. These devices may include at least one central processing unit ("CPU") and memory. According to the convention of those skilled in the art in the field of computer programming, references to operations and symbolic representations of arithmetic or instructions may be performed by various CPUs and memories. Such operations and arithmetic or instructions may be referred to as "executed," "executed by the computer," or "executed by the CPU."

[0199] Those skilled in the art will understand that operations and symbolically represented arithmetic or instructions involve the manipulation of electrical signals by the CPU. The electrical system represents data bits that can cause a resulting transformation or reduction of electrical signals, and maintains these data bits in memory locations of the memory system, thereby reconfiguring or otherwise altering the CPU's operations and processing of other signals. The memory locations where the data bits are maintained are physical locations having specific electrical, magnetic, optical, or organic properties that correspond to or represent the data bits.

[0200] Data bits may also be maintained on computer-readable media, including magnetic disks, optical disks, and any other volatile (e.g., Random Access Memory ("RAM")) or non-volatile (e.g., Read-Only Memory ("ROM")) mass storage systems readable by the CPU. The computer-readable media may include cooperative or interconnected computer-readable media distributed among multiple interconnected processing systems, which may reside exclusively on a processing system or be local or remote to the processing system. Typical embodiments are not limited to the memory described above, and it is understood that other platforms and memories may support the methods described.

[0201] Suitable processors include, for example, general-purpose processors, dedicated processors, conventional processors, digital signal processors (DSPs), multiple microprocessors, one or more microprocessors associated with a DSP core, controllers, microcontrollers, application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), field-programmable gate array (FPGA) circuits, any other type of integrated circuit (IC), and / or state machines.

[0202] Although the present invention has been described in relation to a communication system, it is intended that the system may be implemented in software on a microprocessor / general-purpose computer (not shown). In certain embodiments, one or more functions of various components may be implemented in software that controls a general-purpose computer.

[0203] In addition, although the present invention is illustrated and described herein with reference to specific embodiments, it is not intended to be limited to the details shown. Rather, various modifications can be made in detail within the scope of the claims and their equivalents without departing from the present invention.

Claims

1. A method for wireless communication performed by a wireless transceiver unit (WTRU), Receiving configuration information for one or more reference signal (RS) resource sets, wherein the configuration information indicates a set of slot offset deltas associated with at least one of the RS resource sets of the one or more RS resource sets, Receiving downlink control information (DCI) indicating an RS request, wherein the RS request indicates at least one of the one or more RS resource sets, and the DCI includes a field for indicating a slot offset delta. Based on the field for indicating the aforementioned slot offset delta, the slot offset delta is determined from the set of slot offset deltas, Determining a slot for transmitting RS based at least on the determined slot offset delta, Transmitting the RS in the determined slot, A method that includes this.

2. The method of claim 1, wherein the RS configuration is determined from a set of RS configurations based on any of the following: 1) the search space or CORESET from which the DCI is received, 2) the DCI format, 3) the indications in the DCI, or 4) the Radio Network Temporary Identifier (RNTI) used to scramble a Cyclic Redundancy Check (CRC) for the DCI.

3. The method of claim 1, wherein the one or more RS resource sets include one or more sounding reference signal (SRS) resource sets.

4. The method of claim 1, wherein the slot for transmitting the RS is determined further based on a slot offset associated with the at least one RS resource set.

5. The method according to claim 1, wherein the configuration information of one or more RS resource sets is received via radio resource control (RRC) signaling.

6. The method of claim 1, further comprising determining an RS configuration from a set of RS configurations for RS transmission.

7. The method of claim 1, wherein each of the one or more RS resource sets is associated with a set of slot offsets and a set of slot offset deltas.

8. A wireless transceiver unit (WTRU) equipped with a processor, The aforementioned processor, Receiving configuration information for one or more reference signal (RS) resource sets, wherein the configuration information indicates a set of slot offset deltas associated with at least one of the RS resource sets of the one or more RS resource sets, Receiving downlink control information (DCI) indicating an RS request, wherein the RS request indicates at least one of the one or more RS resource sets, and the DCI includes a field for indicating a slot offset delta. Based on the field for indicating the aforementioned slot offset delta, the slot offset delta is determined from the set of slot offset deltas, Determining a slot for transmitting RS based at least on the determined slot offset delta, Transmitting the RS in the determined slot, A WTRU configured to execute [this].

9. The WTRU of claim 8, wherein the processor is configured to determine an RS configuration from a set of RS configurations based on any of the following: 1) a search space or CORESET from which the DCI is received, 2) the DCI format, 3) an indication in the DCI, or 4) a radio network temporary identifier (RNTI) used to scramble a cyclic redundancy check (CRC) for the DCI.

10. The WTRU of claim 8, wherein the one or more RS resource sets include one or more sounding reference signal (SRS) resource sets.

11. The WTRU of claim 8, wherein the processor is configured to determine a slot for transmitting the RS based on a slot offset associated with the at least one RS resource set.

12. The WTRU according to claim 8, wherein the processor is configured to receive the configuration information of one or more RS resource sets via radio resource control (RRC) signaling.

13. The WTRU of claim 8, wherein the processor is configured to determine an RS configuration from a set of RS configurations for RS transmission.

14. The WTRU of claim 8, wherein each of the one or more RS resource sets is associated with a set of slot offsets and a set of slot offset deltas.

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