WO2025096624A1 - Wtru-assisted dynamic codebook restriction - Google Patents

Abstract

Systems, methods, and instrumentalities are disclosed herein for wireless transmit/receive unit (WTRU)- assisted dynamic codebook restriction. At a first time, the WTRU may send a first channel state information (CSI) report with a first beam indicated by a precoding matrix indicator. The first CSI report may be associated with a first search space comprising a grid of beams (GoB). At a second time, the WTRU may determine a second search space based on the first beam and at least one threshold. The second search space may be smaller than the first search space and centered around the first beam. The WTRU may select a second beam from the second search space. The WTRU may send an indication of the second beam to a network entity.

Description

WTRU-ASSISTED DYNAMIC CODEBOOK RESTRICTION CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims the benefit of U.S. Provisional Application No.63/546,425, filed October 30, 2023 the contents of which is incorporated by reference herein. BACKGROUND [0002] Mobile communications using wireless communication continue to evolve. A fifth generation may be referred to as 5G. A previous (legacy) generation of mobile communication may be, for example, fourth generation (4G) long term evolution (LTE). SUMMARY [0003] Systems, methods, devices, and instrumentalities are described herein related to wireless transmit/receive unit (WTRU)-assisted dynamic codebook restriction. [0004] A device (e.g., a WTRU) may at a first time, send a first channel state information (CSI) report with a first beam indicated by a precoding matrix indicator. The first CSI report may be associated with a first search space comprising a grid of beams (GoB). At a second time, the device may determine a second search space based on the first beam and at least one threshold. The second search space may be smaller than the first search space and centered around the first beam. The device may select a second beam from the second search space. The device may send an indication of the second beam to a network entity. [0005] At a third time, the device may determine a third search space based on the second beam and the at least one threshold. The third search space may be smaller than the first search space and centered around the second beam. The device may select a third beam from the third search space. The device may send an indication of the third beam to the network entity. [0006] The at least one threshold includes a first set of search space dimensions. At a third time, the device may determine a third search space based on the first beam and a second set of search space dimensions. The third search space may be smaller than the first search space and centered around the first beam. The device may select a third beam from the third search space. The device may send an indication of the third beam to the network entity. [0007] The at least one threshold may indicate at least one of a first distance and a second distance. The device may determine the second search space based on the first beam and the at least one threshold by including, in the second search space, beams that are vertically located within the first distance from the first beam and horizontally located within the second distance from the first beam. [0008] The device may determine a first cost associated with a third beam in the second search space, and a second cost associated with a fourth beam in the second search space. The device may select the third beam or the fourth beam, as the second beam, based on the first cost and the second cost. [0009] The device may select a third beam from the second search space. The device may send an indication of the third beam to a network entity. At a third time, the device may determine a third search space and a fourth search space. The third search space may be smaller than the first search space and centered around the second beam. The fourth search space may be smaller than the first search space and centered around the third beam. [0010] The at least one threshold may include a set of search space dimensions. The device may determine the set of search space dimensions based on one or more parameters. The device may send an indication of the set of search space dimensions to the network entity. [0011] The first CSI report may include an indication that dynamic codebook restrictions are applicable. BRIEF DESCRIPTION OF THE DRAWINGS [0012] Furthermore, like reference numerals in the figures indicate like elements, and wherein: [0013] FIG.1A is a system diagram illustrating an example communications system in which one or more disclosed embodiments may be implemented. [0014] FIG.1B is a system diagram illustrating an example wireless transmit/receive unit (WTRU) that may be used within the communications system illustrated in FIG.1A according to an embodiment. [0015] FIG.1C is a system diagram illustrating an example radio access network (RAN) and an example core network (CN) that may be used within the communications system illustrated in FIG.1A according to an embodiment. [0016] FIG.1D is a system diagram illustrating a further example RAN and a further example CN that may be used within the communications system illustrated in FIG.1A according to an embodiment. [0017] FIGs.2A and 2B illustrate an example technique for a WTRU to search and report a precoding matrix indicator (PMI) from a restricted codebook subset. DETAILED DESCRIPTION [0018] FIG.1A is a diagram illustrating an example communications system 100 in which one or more disclosed embodiments may be implemented. The communications system 100 may be a multiple access system that provides content, such as voice, data, video, messaging, broadcast, etc., to multiple wireless users. The communications system 100 may enable multiple wireless users to access such content through the sharing of system resources, including wireless bandwidth. For example, the communications systems 100 may employ one or more channel access methods, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single-carrier FDMA (SC-FDMA), zero-tail unique-word DFT-Spread OFDM (ZT UW DTS-s OFDM), unique word OFDM (UW-OFDM), resource block-filtered OFDM, filter bank multicarrier (FBMC), and the like. [0019] As shown in FIG.1A, the communications system 100 may include wireless transmit/receive units (WTRUs) 102a, 102b, 102c, 102d, a RAN 104/113, a CN 106/115, a public switched telephone network (PSTN) 108, the Internet 110, and other networks 112, though it will be appreciated that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and/or network elements. Each of the WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and/or communicate in a wireless environment. By way of example, the WTRUs 102a, 102b, 102c, 102d, any of which may be referred to as a “station” and/or a “STA”, may be configured to transmit and/or receive wireless signals and may include a user equipment (WTRU), a mobile station, a fixed or mobile subscriber unit, a subscription-based unit, a pager, a cellular telephone, a personal digital assistant (PDA), a smartphone, a laptop, a netbook, a personal computer, a wireless sensor, a hotspot or Mi-Fi device, an Internet of Things (IoT) device, a watch or other wearable, a head-mounted display (HMD), a vehicle, a drone, a medical device and applications (e.g., remote surgery), an industrial device and applications (e.g., a robot and/or other wireless devices operating in an industrial and/or an automated processing chain contexts), a consumer electronics device, a device operating on commercial and/or industrial wireless networks, and the like. Any of the WTRUs 102a, 102b, 102c and 102d may be interchangeably referred to as a WTRU. [0020] The communications systems 100 may also include a base station 114a and/or a base station 114b. Each of the base stations 114a, 114b may be any type of device configured to wirelessly interface with at least one of the WTRUs 102a, 102b, 102c, 102d to facilitate access to one or more communication networks, such as the CN 106/115, the Internet 110, and/or the other networks 112. By way of example, the base stations 114a, 114b may be a base transceiver station (BTS), a Node-B, an eNode B, a Home Node B, a Home eNode B, a gNB, a NR NodeB, a site controller, an access point (AP), a wireless router, and the like. While the base stations 114a, 114b are each depicted as a single element, it will be appreciated that the base stations 114a, 114b may include any number of interconnected base stations and/or network elements. [0021] The base station 114a may be part of the RAN 104/113, which may also include other base stations and/or network elements (not shown), such as a base station controller (BSC), a radio network controller (RNC), relay nodes, etc. The base station 114a and/or the base station 114b may be configured to transmit and/or receive wireless signals on one or more carrier frequencies, which may be referred to as a cell (not shown). These frequencies may be in licensed spectrum, unlicensed spectrum, or a combination of licensed and unlicensed spectrum. A cell may provide coverage for a wireless service to a specific geographical area that may be relatively fixed or that may change over time. The cell may further be divided into cell sectors. For example, the cell associated with the base station 114a may be divided into three sectors. Thus, in one embodiment, the base station 114a may include three transceivers, i.e., one for each sector of the cell. In an embodiment, the base station 114a may employ multiple-input multiple output (MIMO) technology and may utilize multiple transceivers for each sector of the cell. For example, beamforming may be used to transmit and/or receive signals in desired spatial directions. [0022] The base stations 114a, 114b may communicate with one or more of the WTRUs 102a, 102b, 102c, 102d over an air interface 116, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet (UV), visible light, etc.). The air interface 116 may be established using any suitable radio access technology (RAT). [0023] More specifically, as noted above, the communications 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, and the like. For example, the base station 114a in the RAN 104/113 and the WTRUs 102a, 102b, 102c may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may establish the air interface 115/116/117 using wideband CDMA (WCDMA). WCDMA may include communication protocols such as High-Speed Packet Access (HSPA) and/or Evolved HSPA (HSPA+). HSPA may include High-Speed Downlink (DL) Packet Access (HSDPA) and/or High-Speed UL Packet Access (HSUPA). [0024] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which may establish the air interface 116 using Long Term Evolution (LTE) and/or LTE-Advanced (LTE-A) and/or LTE-Advanced Pro (LTE-A Pro). [0025] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as NR Radio Access , which may establish the air interface 116 using New Radio (NR). [0026] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement multiple radio access technologies. For example, the base station 114a and the WTRUs 102a, 102b, 102c may implement LTE radio access and NR radio access together, for instance using dual connectivity (DC) principles. Thus, the air interface utilized by WTRUs 102a, 102b, 102c may be characterized by multiple types of radio access technologies and/or transmissions sent to/from multiple types of base stations (e.g., a eNB and a gNB). [0027] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement radio technologies such as IEEE 802.11 (i.e., Wireless Fidelity (WiFi), IEEE 802.16 (i.e., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA20001X, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile communications (GSM), Enhanced Data rates for GSM Evolution (EDGE), GSM EDGE (GERAN), and the like. [0028] The base station 114b in FIG.1A may be a wireless router, Home Node B, Home eNode B, or access point, for example, and may utilize any suitable RAT for facilitating wireless connectivity in a localized area, such as a place of business, a home, a vehicle, a campus, an industrial facility, an air corridor (e.g., for use by drones), a roadway, and the like. In one embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.11 to establish a wireless local area network (WLAN). In an embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.15 to establish a wireless personal area network (WPAN). In yet another embodiment, the base station 114b and the WTRUs 102c, 102d may utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR etc.) to establish a picocell or femtocell. As shown in FIG.1A, the base station 114b may have a direct connection to the Internet 110. Thus, the base station 114b may not be required to access the Internet 110 via the CN 106/115. [0029] The RAN 104/113 may be in communication with the CN 106/115, which may be any type of network configured to provide voice, data, applications, and/or voice over internet protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. The data may have varying quality of service (QoS) requirements, such as differing throughput requirements, latency requirements, error tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, and the like. The CN 106/115 may provide call control, billing services, mobile location-based services, pre-paid calling, Internet connectivity, video distribution, etc., and/or perform high-level security functions, such as user authentication. Although not shown in FIG.1A, it will be appreciated that the RAN 104/113 and/or the CN 106/115 may be in direct or indirect communication with other RANs that employ the same RAT as the RAN 104/113 or a different RAT. For example, in addition to being connected to the RAN 104/113, which may be utilizing a NR radio technology, the CN 106/115 may also be in communication with another RAN (not shown) employing a GSM, UMTS, CDMA 2000, WiMAX, E-UTRA, or WiFi radio technology. [0030] The CN 106/115 may also serve as a gateway for the WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the Internet 110, and/or the other networks 112. The PSTN 108 may include circuit- switched telephone networks that provide plain old telephone service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices that use common communication protocols, such as the transmission control protocol (TCP), user datagram protocol (UDP) and/or the internet protocol (IP) in the TCP/IP internet protocol suite. The networks 112 may include wired and/or wireless communications networks owned and/or operated by other service providers. For example, the networks 112 may include another CN connected to one or more RANs, which may employ the same RAT as the RAN 104/113 or a different RAT. [0031] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communications system 100 may include multi-mode capabilities (e.g., the WTRUs 102a, 102b, 102c, 102d may include multiple transceivers for communicating with different wireless networks over different wireless links). For example, the WTRU 102c shown in FIG.1A may be configured to communicate with the base station 114a, which may employ a cellular-based radio technology, and with the base station 114b, which may employ an IEEE 802 radio technology. [0032] FIG.1B is a system diagram illustrating an example WTRU 102. As shown in FIG.1B, the WTRU 102 may include a processor 118, a transceiver 120, a transmit/receive element 122, a speaker/microphone 124, a keypad 126, a display/touchpad 128, non-removable memory 130, removable memory 132, a power source 134, a global positioning system (GPS) chipset 136, and/or other peripherals 138, among others. It will be appreciated that the WTRU 102 may include any sub-combination of the foregoing elements while remaining consistent with an embodiment. [0033] The processor 118 may be a general purpose processor, a special purpose processor, a conventional processor, a digital signal processor (DSP), a plurality of microprocessors, one or more microprocessors in association with a DSP core, a controller, a microcontroller, Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs) circuits, any other type of integrated circuit (IC), a state machine, and the like. The processor 118 may perform signal coding, data processing, power control, input/output processing, and/or any other functionality that enables the WTRU 102 to operate in a wireless environment. The processor 118 may be coupled to the transceiver 120, which may be coupled to the transmit/receive element 122. While FIG.1B depicts the processor 118 and the transceiver 120 as separate components, it will be appreciated that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip. [0034] The transmit/receive element 122 may be configured to transmit signals to, or receive signals from, a base station (e.g., the base station 114a) over the air interface 116. For example, in one embodiment, the transmit/receive element 122 may be an antenna configured to transmit and/or receive RF signals. In an embodiment, the transmit/receive element 122 may be an emitter/detector configured to transmit and/or receive IR, UV, or visible light signals, for example. In yet another embodiment, the transmit/receive element 122 may be configured to transmit and/or receive both RF and light signals. It will be appreciated that the transmit/receive element 122 may be configured to transmit and/or receive any combination of wireless signals. [0035] Although the transmit/receive element 122 is depicted in FIG.1B as a single element, the WTRU 102 may include any number of transmit/receive elements 122. More specifically, the WTRU 102 may employ MIMO technology. Thus, in one embodiment, the WTRU 102 may include two or more transmit/receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals over the air interface 116. [0036] The transceiver 120 may be configured to modulate the signals that are to be transmitted by the transmit/receive element 122 and to demodulate the signals that are received by the transmit/receive element 122. As noted above, the WTRU 102 may have multi-mode capabilities. Thus, the transceiver 120 may include multiple transceivers for enabling the WTRU 102 to communicate via multiple RATs, such as NR and IEEE 802.11, for example. [0037] The processor 118 of the WTRU 102 may be coupled to, and may receive user input data from, the speaker/microphone 124, the keypad 126, and/or the display/touchpad 128 (e.g., a liquid crystal display (LCD) display unit or organic light-emitting diode (OLED) display unit). The processor 118 may also output user data to the speaker/microphone 124, the keypad 126, and/or the display/touchpad 128. In addition, the processor 118 may access information from, and store data in, any type of suitable memory, such as the non-removable memory 130 and/or the removable memory 132. 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 from, and store data in, memory that is not physically located on the WTRU 102, such as on a server or a home computer (not shown). [0038] The processor 118 may receive power from the power source 134, and may be configured to distribute and/or control the power to the other components in the WTRU 102. The power source 134 may be any suitable device for powering the WTRU 102. For example, the power source 134 may include one or more dry cell batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, and the like. [0039] The processor 118 may also be coupled to the GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) regarding the current location of the WTRU 102. In addition to, or in lieu of, the information from the GPS chipset 136, the WTRU 102 may receive location information over the air interface 116 from a base station (e.g., base stations 114a, 114b) and/or determine its location based on the timing of the signals being received from two or more nearby base stations. It will be appreciated that the WTRU 102 may acquire location information by way of any suitable location- determination method while remaining consistent with an embodiment. [0040] The processor 118 may further be coupled to other peripherals 138, which may include one or more software and/or hardware modules that provide additional features, functionality and/or wired or wireless connectivity. For example, the peripherals 138 may include an accelerometer, an e-compass, a satellite transceiver, a digital camera (for photographs and/or video), 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 peripherals 138 may include one or more sensors, the sensors may be one or more of a gyroscope, an accelerometer, a hall effect sensor, a magnetometer, an orientation sensor, a proximity sensor, a temperature sensor, a time sensor; a geolocation sensor; an altimeter, a light sensor, a touch sensor, a magnetometer, a barometer, a gesture sensor, a biometric sensor, and/or a humidity sensor. [0041] The WTRU 102 may include a full duplex radio for which transmission and reception of some or all of the signals (e.g., associated with particular subframes for both the UL (e.g., for transmission) and downlink (e.g., for reception) may be concurrent and/or simultaneous. The full duplex radio may include an interference management unit to reduce and or substantially eliminate self-interference via either hardware (e.g., a choke) or signal processing via a processor (e.g., a separate processor (not shown) or via processor 118). In an embodiment, the WRTU 102 may include a half-duplex radio for which transmission and reception of some or all of the signals (e.g., associated with particular subframes for either the UL (e.g., for transmission) or the downlink (e.g., for reception)). [0042] FIG.1C is a system diagram illustrating the RAN 104 and the CN 106 according to an embodiment. As noted above, the RAN 104 may employ an E-UTRA radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 104 may also be in communication with the CN 106. [0043] The RAN 104 may include eNode-Bs 160a, 160b, 160c, though it will be appreciated that the RAN 104 may include any number of eNode-Bs while remaining consistent with an embodiment. The eNode-Bs 160a, 160b, 160c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In one embodiment, the eNode-Bs 160a, 160b, 160c may implement MIMO technology. Thus, the eNode-B 160a, for example, may use multiple antennas to transmit wireless signals to, and/or receive wireless signals from, the WTRU 102a. [0044] Each of the eNode-Bs 160a, 160b, 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the UL and/or DL, and the like. As shown in FIG.1C, the eNode-Bs 160a, 160b, 160c may communicate with one another over an X2 interface. [0045] The CN 106 shown in FIG.1C may include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (or PGW) 166. While each of the foregoing elements are depicted as part of the CN 106, it will be appreciated that any of these elements may be owned and/or operated by an entity other than the CN operator. [0046] The MME 162 may be connected to each of the eNode-Bs 162a, 162b, 162c in the RAN 104 via an S1 interface and may serve as a control node. For example, the MME 162 may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, bearer activation/deactivation, selecting a particular serving gateway during an initial attach of the WTRUs 102a, 102b, 102c, and the like. The MME 162 may provide a control plane function for switching between the RAN 104 and other RANs (not shown) that employ other radio technologies, such as GSM and/or WCDMA. [0047] The SGW 164 may be connected to each of the eNode Bs 160a, 160b, 160c in the RAN 104 via the S1 interface. The SGW 164 may generally route and forward user data packets to/from the WTRUs 102a, 102b, 102c. The SGW 164 may perform other functions, such as anchoring user planes during inter- eNode B handovers, triggering paging when DL data is available for the WTRUs 102a, 102b, 102c, managing and storing contexts of the WTRUs 102a, 102b, 102c, and the like. [0048] The SGW 164 may be connected to the PGW 166, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices. [0049] The CN 106 may facilitate communications with other networks. For example, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to circuit-switched networks, such as the PSTN 108, to facilitate communications between the WTRUs 102a, 102b, 102c and traditional land-line communications devices. For example, the CN 106 may include, or may communicate with, an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that serves as an interface between the CN 106 and the PSTN 108. In addition, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to the other networks 112, which may include other wired and/or wireless networks that are owned and/or operated by other service providers. [0050] Although the WTRU is described in FIGS.1A-1D as a wireless terminal, it is contemplated that in certain representative embodiments that such a terminal may use (e.g., temporarily or permanently) wired communication interfaces with the communication network. [0051] In representative embodiments, the other network 112 may be a WLAN. [0052] A WLAN in Infrastructure Basic Service Set (BSS) mode may have an Access Point (AP) for the BSS and one or more stations (STAs) associated with the AP. The AP may have an access or an interface to a Distribution System (DS) or another type of wired/wireless network that carries traffic in to and/or out of the BSS. Traffic to STAs that originates from outside the BSS may arrive through the AP and may be delivered to the STAs. Traffic originating from STAs to destinations outside the BSS may be sent to the AP to be delivered to respective destinations. Traffic between STAs within the BSS may be sent through the AP, for example, where the source STA may send traffic to the AP and the AP may deliver the traffic to the destination STA. The traffic between STAs within a BSS may be considered and/or referred to as peer-to- peer traffic. The peer-to-peer traffic may be sent between (e.g., directly between) the source and destination STAs with a direct link setup (DLS). In certain representative embodiments, the DLS may use an 802.11e DLS or an 802.11z tunneled DLS (TDLS). A WLAN using an Independent BSS (IBSS) mode may not have an AP, and the STAs (e.g., all of the STAs) within or using the IBSS may communicate directly with each other. The IBSS mode of communication may sometimes be referred to herein as an “ad- hoc” mode of communication. [0053] When using the 802.11ac infrastructure mode of operation or a similar mode of operations, the AP may transmit a beacon on a fixed channel, such as a primary channel. The primary channel may be a fixed width (e.g., 20 MHz wide bandwidth) or a dynamically set width via signaling. The primary channel may be the operating channel of the BSS and may be used by the STAs to establish a connection with the AP. In certain representative embodiments, Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) may be implemented, for example in in 802.11 systems. For CSMA/CA, the STAs (e.g., every STA), including the AP, may sense the primary channel. If the primary channel is sensed/detected and/or determined to be busy by a particular STA, the particular STA may back off. One STA (e.g., only one station) may transmit at any given time in a given BSS. [0054] High Throughput (HT) STAs may use a 40 MHz wide channel for communication, for example, via a combination of the primary 20 MHz channel with an adjacent or nonadjacent 20 MHz channel to form a 40 MHz wide channel. [0055] Very High Throughput (VHT) STAs may support 20MHz, 40 MHz, 80 MHz, and/or 160 MHz wide channels. The 40 MHz, and/or 80 MHz, channels may be formed by combining contiguous 20 MHz channels. A 160 MHz channel may be formed by combining 8 contiguous 20 MHz channels, or by combining two non-contiguous 80 MHz channels, which may be referred to as an 80+80 configuration. For the 80+80 configuration, the data, after channel encoding, may be passed through a segment parser that may divide the data into two streams. Inverse Fast Fourier Transform (IFFT) processing, and time domain processing, may be done on each stream separately. The streams may be mapped on to the two 80 MHz channels, and the data may be transmitted by a transmitting STA. At the receiver of the receiving STA, the above described operation for the 80+80 configuration may be reversed, and the combined data may be sent to the Medium Access Control (MAC). [0056] Sub 1 GHz modes of operation are supported by 802.11af and 802.11ah. The channel operating bandwidths, and carriers, are reduced in 802.11af and 802.11ah relative to those used in 802.11n, and 802.11ac.802.11af supports 5 MHz, 10 MHz and 20 MHz bandwidths in the TV White Space (TVWS) spectrum, and 802.11ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths using non- TVWS spectrum. According to a representative 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, for example, limited capabilities including support for (e.g., only support for) certain and/or limited bandwidths. The MTC devices may include a battery with a battery life above a threshold (e.g., to maintain a very long battery life). [0057] WLAN systems, which may support multiple channels, and channel bandwidths, such as 802.11n, 802.11ac, 802.11af, and 802.11ah, include a channel which may be designated as the primary channel. The primary channel may have a bandwidth equal to the largest common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel may be set and/or limited by a STA, from among all STAs in operating in a BSS, which supports the smallest bandwidth operating mode. In the example of 802.11ah, the primary channel may be 1 MHz wide for STAs (e.g., MTC type devices) that support (e.g., only support) a 1 MHz mode, even if the AP, and other STAs in the BSS support 2 MHz, 4 MHz, 8 MHz, 16 MHz, and/or other channel bandwidth operating modes. Carrier sensing and/or Network Allocation Vector (NAV) settings may depend on the status of the primary channel. If the primary channel is busy, for example, due to a STA (which supports only a 1 MHz operating mode), transmitting to the AP, the entire available frequency bands may be considered busy even though a majority of the frequency bands remains idle and may be available. [0058] In the United States, the available frequency bands, which may be used by 802.11ah, are from 902 MHz to 928 MHz. In Korea, the available frequency bands are from 917.5 MHz to 923.5 MHz. In Japan, the available frequency bands are from 916.5 MHz to 927.5 MHz. The total bandwidth available for 802.11ah is 6 MHz to 26 MHz depending on the country code. [0059] FIG.1D is a system diagram illustrating the RAN 113 and the CN 115 according to an embodiment. As noted above, the RAN 113 may employ an NR radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 113 may also be in communication with the CN 115. [0060] The RAN 113 may include gNBs 180a, 180b, 180c, though it will be appreciated that the RAN 113 may include any number of gNBs while remaining consistent with an embodiment. The gNBs 180a, 180b, 180c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In one embodiment, the gNBs 180a, 180b, 180c may implement MIMO technology. For example, gNBs 180a, 108b may utilize beamforming to transmit signals to and/or receive signals from the gNBs 180a, 180b, 180c. Thus, the gNB 180a, for example, may use multiple antennas to transmit wireless signals to, and/or receive wireless signals from, the WTRU 102a. In an embodiment, the gNBs 180a, 180b, 180c may implement carrier aggregation technology. For example, the gNB 180a may transmit multiple component carriers to the WTRU 102a (not shown). A subset of these component carriers may be on unlicensed spectrum while the remaining component carriers may be on licensed spectrum. In an embodiment, the gNBs 180a, 180b, 180c may implement Coordinated Multi-Point (CoMP) technology. For example, WTRU 102a may receive coordinated transmissions from gNB 180a and gNB 180b (and/or gNB 180c). [0061] The WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using transmissions associated with a scalable numerology. For example, the OFDM symbol spacing and/or OFDM subcarrier spacing may vary for different transmissions, different cells, and/or different portions of the wireless transmission spectrum. The WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using subframe or transmission time intervals (TTIs) of various or scalable lengths (e.g., containing varying number of OFDM symbols and/or lasting varying lengths of absolute time). [0062] The gNBs 180a, 180b, 180c may be configured to communicate with the WTRUs 102a, 102b, 102c in a standalone configuration and/or a non-standalone configuration. In the standalone configuration, WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c without also accessing other RANs (e.g., such as eNode-Bs 160a, 160b, 160c). In the standalone configuration, WTRUs 102a, 102b, 102c may utilize one or more of gNBs 180a, 180b, 180c as a mobility anchor point. In the standalone configuration, WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using signals in an unlicensed band. In a non-standalone configuration WTRUs 102a, 102b, 102c may communicate with/connect to gNBs 180a, 180b, 180c while also communicating with/connecting to another RAN such as eNode-Bs 160a, 160b, 160c. For example, WTRUs 102a, 102b, 102c may implement DC principles to communicate with one or more gNBs 180a, 180b, 180c and one or more eNode-Bs 160a, 160b, 160c substantially simultaneously. In the non-standalone configuration, eNode-Bs 160a, 160b, 160c may serve as a mobility anchor for WTRUs 102a, 102b, 102c and gNBs 180a, 180b, 180c may provide additional coverage and/or throughput for servicing WTRUs 102a, 102b, 102c. [0063] Each of the gNBs 180a, 180b, 180c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the UL and/or DL, support of network slicing, dual connectivity, interworking between NR and E- UTRA, routing of user plane data towards User Plane Function (UPF) 184a, 184b, routing of control plane information towards Access and Mobility Management Function (AMF) 182a, 182b and the like. As shown in FIG.1D, the gNBs 180a, 180b, 180c may communicate with one another over an Xn interface. [0064] The CN 115 shown in FIG.1D may include at least one AMF 182a, 182b, at least one UPF 184a,184b, at least one Session Management Function (SMF) 183a, 183b, and possibly a Data Network (DN) 185a, 185b. While each of the foregoing elements are depicted as part of the CN 115, it will be appreciated that any of these elements may be owned and/or operated by an entity other than the CN operator. [0065] The AMF 182a, 182b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via an N2 interface and may serve as a control node. For example, the AMF 182a, 182b may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, support for network slicing (e.g., handling of different PDU sessions with different requirements), selecting a particular SMF 183a, 183b, management of the registration area, termination of NAS signaling, mobility management, and the like. Network slicing may be used by the AMF 182a, 182b in order to customize CN support for WTRUs 102a, 102b, 102c based on the types of services being utilized WTRUs 102a, 102b, 102c. For example, different network slices may be established for different use cases such as services relying on ultra-reliable low latency (URLLC) access, services relying on enhanced massive mobile broadband (eMBB) access, services for machine type communication (MTC) access, and/or the like. The AMF 162 may provide a control plane function for switching between the RAN 113 and other RANs (not shown) that employ other radio technologies, such as LTE, LTE-A, LTE-A Pro, and/or non-3GPP access technologies such as WiFi. [0066] The SMF 183a, 183b may be connected to an AMF 182a, 182b in the CN 115 via an N11 interface. The SMF 183a, 183b may also be connected to a UPF 184a, 184b in the CN 115 via an N4 interface. The SMF 183a, 183b may select and control the UPF 184a, 184b and configure the routing of traffic through the UPF 184a, 184b. The SMF 183a, 183b may perform other functions, such as managing and allocating WTRU IP address, managing PDU sessions, controlling policy enforcement and QoS, providing downlink data notifications, and the like. A PDU session type may be IP-based, non-IP based, Ethernet-based, and the like. [0067] The UPF 184a, 184b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via an N3 interface, which may provide the WTRUs 102a, 102b, 102c with access to packet- switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices. The UPF 184, 184b may perform other functions, such as routing and forwarding packets, enforcing user plane policies, supporting multi-homed PDU sessions, handling user plane QoS, buffering downlink packets, providing mobility anchoring, and the like. [0068] The CN 115 may facilitate communications with other networks. For example, the CN 115 may include, or may communicate with, an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that serves as an interface between the CN 115 and the PSTN 108. In addition, the CN 115 may provide the WTRUs 102a, 102b, 102c with access to the other networks 112, which may include other wired and/or wireless networks that are owned and/or operated by other service providers. In one embodiment, the WTRUs 102a, 102b, 102c may be connected to a local Data Network (DN) 185a, 185b through the UPF 184a, 184b via the N3 interface to the UPF 184a, 184b and an N6 interface between the UPF 184a, 184b and the DN 185a, 185b. [0069] In view of Figures 1A-1D, and the corresponding description of Figures 1A-1D, one or more, or all, of the functions described herein with regard to one or more of: WTRU 102a-d, Base Station 114a-b, eNode-B 160a-c, MME 162, SGW 164, PGW 166, gNB 180a-c, AMF 182a-b, UPF 184a-b, SMF 183a-b, DN 185a-b, and/or any other device(s) described herein, may be performed by one or more emulation devices (not shown). The emulation devices may be one or more devices configured to emulate one or more, or all, of the functions described herein. For example, the emulation devices may be used to test other devices and/or to simulate network and/or WTRU functions. [0070] The emulation devices may be designed to implement one or more tests of other devices in a lab environment and/or in an operator network environment. For example, the one or more emulation devices may perform the one or more, or all, functions while being fully or partially implemented and/or deployed as part of a wired and/or wireless communication network in order to test other devices within the communication network. The one or more emulation devices may perform the one or more, or all, functions while being temporarily implemented/deployed as part of a wired and/or wireless communication network. The emulation device may be directly coupled to another device for purposes of testing and/or may performing testing using over-the-air wireless communications. [0071] The one or more emulation devices may perform the one or more, including all, functions while not being implemented/deployed as part of a wired and/or wireless communication network. For example, the emulation devices may be utilized in a testing scenario in a testing laboratory and/or a non-deployed (e.g., testing) wired and/or wireless communication network in order to implement testing of one or more components. The one or more emulation devices may be test equipment. Direct RF coupling and/or wireless communications via RF circuitry (e.g., which may include one or more antennas) may be used by the emulation devices to transmit and/or receive data. [0072] In examples (e.g., in multiple input multiple output (MIMO)), the maximum number of CSI-RS ports may increase from 32 to 64 with high probability (e.g., to efficiently measure the channel and provide narrower beam for each user). [0073] A larger antenna array (e.g., with more transmission (TX)) for higher-order spatial multiplexing may be used (e.g., for multi-user MIMO (MU-MIMO)). A narrower beam (e.g., and consequently higher throughput) may be used for multiple users. Codebook restriction may be used to provide less overhead. [0074] Multiple (e.g., 64) CSI-RS ports may be used. In some examples, the number of CSI-RS ports may be upper bounded to 32. To provide more TX for higher-order spatial multiplexing (e.g., for MU- MIMO), the upper bound may be increased to 64 ports. Increasing the number of CSI-RS ports may cause CSI feedback overhead and complexity at a WTRU to increase. CSI-RS resources may be designed with limited overhead. [0075] CSI-RS ports may be upper bounded (e.g., by 64 ports). A WTRU may receive CSI-RS with 64 ports configuration with a grid-of-beams (GoB). The WTRU may receive a PUCCH resource configuration. The WTRU may measure the channel with 64 CSI-RS ports. The WTRU may report a precoding matrix indicator (PMI), rank indicator (RI), and/or channel quality indicator (CQI) to a network entity (e.g., gNB). The WTRU may select the best beam. The WTRU may report the best beam to the gNB. For example, the WTRU may determine a first cost associated with a third beam in the second search space and a second cost associated with a fourth beam in the second search space. The WTRU may select the third beam or the fourth beam (e.g., as the second beam) based on the first cost and the second cost. [0076] The number of CSI-RS resources may be upper bounded by 32 ports. To serve a greater number of WTRUs with narrower beams, the upper bound may be increased to 64 ports. As the array grows, the spatial properties may no longer be uniform across the array (e.g., from the WTRU’s point of view). The WTRU may see more than two separate analog beams from the gNB. A (e.g., single) analog beam may not be an accurate representation for the whole array. [0077] Increasing the maximum number of CSI-RS ports to 64 may have one or more effects. Techniques may be designed in such a way to reduce feedback overhead. CSI-RS ports may be partitioned to assist measuring the co-phasing among the ports. The ports (e.g., all the ports) of the array may be efficiently measured (e.g., without new designs or procedures). [0078] As used herein, the terms ‘a’ and ‘an’ and similar phrases are to be interpreted as ‘one or more’ and ‘at least one’. Similarly, any term which ends with the suffix ‘(s)’ is to be interpreted as ‘one or more’ and ‘at least one’. The term ‘may’ is to be interpreted as ‘may, for example’. [0079] A sign, symbol, or mark of forward slash ‘/’ is to be interpreted as ‘and/or’ unless particularly mentioned otherwise (e.g., ‘A/B’ may imply ‘A and/or B’). [0080] An example definition of beam is provided herein. A WTRU may transmit or receive a physical channel or reference signal according to at least one spatial domain filter. The term “beam” may be used to refer to a spatial domain filter. [0081] The WTRU may transmit a physical channel or signal using a spatial domain filter (e.g., the same spatial domain filter as the spatial domain filter used for receiving an RS, such as CSI-RS, or a synchronization signal (SS) block). The WTRU transmission may be referred to as “target.” The received RS or SS block may be referred to as “reference” or “source.” In this case, the WTRU may be said to transmit the target physical channel or signal according to a spatial relation with a reference to such RS or SS block. [0082] The WTRU may transmit a first physical channel or signal according to a spatial domain filter (e.g., the same spatial domain filter as the spatial domain filter used for transmitting a second physical channel or signal). The first and second transmissions may be referred to as “target” and “reference” (or “source”), respectively. In such case, the WTRU may be said to transmit the first (target) physical channel or signal according to a spatial relation with a reference to the second (reference) physical channel or signal. [0083] A spatial relation may be implicit, configured by RRC, or signaled by MAC CE or DCI. For example, a WTRU may implicitly transmit PUSCH and DM-RS of PUSCH according to a spatial domain filter (e.g., the same spatial domain filter as an SRS indicated by an SRS resource indicator (SRI) indicated in DCI or configured by RRC). In another example, a spatial relation may be configured by RRC for an SRI or signaled by MAC CE for a PUCCH. The spatial relation may be referred to as a “beam indication.” [0084] The WTRU may receive a first (target) downlink channel or signal according to the same spatial domain filter or spatial reception parameter as a second (reference) downlink channel or signal. For example, the association may exist between a physical channel such as PDCCH or PDSCH and its respective DM-RS. If the first and second signals are reference signals, the association may exist if the WTRU is configured with a quasi-colocation (QCL) assumption type D between corresponding antenna ports. Such association may be configured as a transmission configuration indicator (TCI) state. A WTRU may receive an indication of an association between a CSI-RS or SS block and a DM-RS by an index to a set of TCI states configured by RRC and/or signaled by MAC CE. The indication may be referred to as a “beam indication.” [0085] Feature(s) associated with unified TCI are provided herein. A unified TCI (e.g., a common TCI, a common beam, a common RS, etc.) may refer to a beam/RS to be (e.g., simultaneously) used for multiple physical channels/signals. The term “TCI” may refer to a TCI state that includes at least one source RS to provide a reference (e.g., WTRU assumption) for determining QCL and/or spatial filter. [0086] A WTRU may receive (e.g., from a gNB) an indication of a first unified TCI to be used/applied for a downlink control channel (e.g., PDCCH) and a downlink shared channel (e.g., PDSCH) (e.g., and a downlink RS). The source reference signal(s) in the first unified TCI may provide common QCL information at least for WTRU-dedicated reception on the PDSCH and one or more (e.g., all or subset of) CORESETs in a component carrier (CC). The WTRU may receive (e.g., from a gNB) an indication of a second unified TCI to be used/applied for an uplink control channel (e.g., PUCCH) and an uplink shared channel (e.g., PUSCH) (e.g., and an uplink RS). The source reference signal(s) in the second unified TCI may provide a reference for determining common UL TX spatial filter(s) at least for dynamic-grant/configured-grant based PUSCH and one or more (e.g., all or subset of) dedicated PUCCH resources in a CC. [0087] The WTRU may be configured with a first mode for unified TCI (e.g., SeparateDLULTCI mode). An indicated unified TCI (e.g., the first unified TCI or the second unified TCI) may be applicable for downlink (e.g., based on the first unified TCI) and/or uplink (e.g., based on the second unified TCI). [0088] The WTRU may receive (e.g., from a gNB) an indication of a second unified TCI to be used/applied commonly for a PDCCH, a PDSCH, a PUCCH, and a PUSCH (and a DL RS and/or a UL RS). [0089] The WTRU may be configured with a second mode for unified TCI (e.g., JointTCI mode). An indicated unified TCI (e.g., the third unified TCI) may be applicable for downlink and uplink (e.g., based on the third unified TCI). [0090] The WTRU may determine a TCI state applicable to a transmission or reception by determining a unified TCI state instance applicable to the transmission or reception. The WTRU may determine a TCI state corresponding to the unified TCI state instance. A transmission may include (e.g., at least) PUCCH, PUSCH, and SRS. A reception may include (e.g., at least) PDCCH, PDSCH, and CSI-RS. A unified TCI state instance may be referred to TCI state group, TCI state process, unified TCI pool, a group of TCI states, a set of time-domain instances/stamps/slots/symbols, and/or a set of frequency-domain instances/RBs/subbands, etc. A unified TCI state instance may be equivalent to, or identified with, a control resource set (CORESET) pool identity (e.g., CORESETPoolIndex, a TRP indicator, and/or the like). [0091] As used herein, unified TCI may be used interchangeably with one or more of unified TCI-states, unified TCI instance, TCI, and TCI-state (e.g., while remaining consistent within this disclosure). [0092] Feature(s) associated with a transmission/reception point (TRP) and multi-TRP (MTRP or M- TRP) are provided herein. [0093] As used herein, a TRP may be interchangeably used with one or more of transmission point (TP), reception point (RP), radio remote head (RRH), distributed antenna (DA), base station (BS), a sector (e.g., of a BS), a cell (e.g., a geographical cell area served by a BS), a CSI-RS resource set (e.g., while remaining consistent within this disclosure). As used herein, multi-TRP may be interchangeably used with one or more of MTRP, M-TRP, and multiple TRPs (e.g., while remaining consistent within this disclosure). [0094] Example configuration(s) of TRP(s), SRI(s), and pathloss (PL) reference RS(s) are provided herein. [0095] A WTRU may be configured with (or may receive configuration of) one or more TRPs (e.g., to which the WTRU may transmit and/or from which the WTRU may receive). The WTRU may be configured with one or more TRPs for one or more cells. A cell may be a serving cell, secondary cell, and/or the like. [0096] A WTRU may be configured with at least one RS (e.g., for the purpose of channel measurement). This RS may be denoted as a channel measurement resource (CMR). The CMR may include a CSI-RS, SSB, or other downlink RS (e.g., transmitted from the TRP to a WTRU). The CMR may be configured or associated with a TCI state. The WTRU may be configured with a CMR group (e.g., where CMRs transmitted from the same TRP may be configured). Each group may be identified by a CMR group index (e.g., group 1). A WTRU may be configured with a (e.g., one) CMR group per TRP. The WTRU may receive a linkage between a (e.g., one) CMR group index and another CMR group index, or between a (e.g., one) RS index from a (e.g., one) CMR group and another RS index from another group. [0097] A WTRU may be configured with (or receive configuration of) one or more PL reference groups (e.g., sets) and/or one or more SRS groups, SRS resource indicator (SRI), or SRS resource sets. [0098] A PL reference group may correspond to, or may be associated with, a TRP. A PL reference group may include, identify, correspond to, or be associated with one or more TCI states, SRIs, reference signal sets (e.g., CSI-RS set, SRI sets), CORESET index, and/or reference signals (e.g., CSI-RS, SSB). [0099] A WTRU may receive a configuration (e.g., any configuration described herein). The configuration may be sent by (e.g., received from) a gNB or TRP. For example, the WTRU may receive configuration of one or more TRPs, one or more PL reference groups, and/or one or more SRI sets. A WTRU may (e.g., implicitly) determine an association between a RS set/group and a TRP. For example, if the WTRU is configured with two SRS resource sets, the WTRU may determine to transmit to TRP1 with SRS in the first resource set, and to TRP2 with SRS in the second resource set. The configuration may be sent via RRC signaling. [0100] In the examples and embodiments described herein, TRP, PL reference group, SRI group, and SRI set may be used interchangeably. The terms set and group may be used interchangeably herein. [0101] Feature(s) associated with CSI components are provided herein. [0102] A WTRU may report a subset of CSI components. The CSI components may correspond to at least a CSI-RS resource indicator (CRI) (e.g., which indicates one CSI-RS resource out of a CSI-RS resource set), a SSB resource indicator (SSBRI) (e.g., which indicates one SSB out of a set of SSBs), an indication of a panel used for reception at the WTRU (e.g., such as a panel identity or group identity), measurements (e.g., such as L1-RSRP, L1-SINR) taken from SSB or CSI-RS (e.g. cri-RSRP, cri-SINR, ssb-Index-RSRP, ssb-Index-SINR), and/or other channel state information (e.g., such as at least rank indicator (RI), channel quality indicator (CQI), precoding matrix indicator (PMI), layer index (LI), and/or the like). [0103] Feature(s) associated with property of a grant or assignment are provided herein. [0104] A property of a grant or assignment may include one or more of the following: a frequency allocation; an aspect of time allocation, such as a duration; a priority; a modulation and coding scheme; a transport block size; a number of spatial layers; a number of transport blocks; a TCI state, CRI or SRI; a number of repetitions; whether the repetition scheme is Type A or Type B; whether the grant is a configured grant type 1, type 2 or a dynamic grant; whether the assignment is a dynamic assignment or a semi-persistent scheduling (configured) assignment; a configured grant index or a semi-persistent assignment index; a periodicity of a configured grant or assignment; a channel access priority class (CAPC); any parameter provided in a DCI, by MAC, or by RRC for the scheduling the grant or assignment; and/or the like. [0105] An indication by DCI may include one or more of the following: an explicit indication by a DCI field or by RNTI used to mask CRC of the PDCCH; an implicit indication by a property (e.g., such as DCI format, DCI size, CORESET or search space, aggregation level, first resource element of the received DCI, for example, index of first control channel element, and/or the like). The mapping between the property and the value may be signaled by RRC or MAC. [0106] As used herein, a signal may be interchangeably used with one or more of following: a sounding reference signal (SRS); channel state information (e.g., CSI reference signal (CSI-RS)); a demodulation reference signal (DM-RS); a phase tracking reference signal (PT-RS); a synchronization signal block (SSB); an/or the like. [0107] As used herein, a channel may be interchangeably used with one or more of following: a physical downlink control channel (PDCCH); a physical downlink shared channel (PDSCH); a physical uplink control channel (PUCCH); a physical uplink shared channel (PUSCH);a physical random-access channel (PRACH); etc. [0108] As used herein, downlink reception may be used interchangeably with receive (Rx or RX) occasion, PDCCH, PDSCH, SSB reception, etc. As used herein, uplink transmission may be used interchangeably with transmission (Tx or TX) occasion, PUCCH, PUSCH, PRACH, SRS transmission, etc. As used herein, RS may be interchangeably used with one or more of RS resource, RS resource set, RS port and RS port group, etc. As used herein, RS may be interchangeably used with one or more of SSB, CSI-RS, SRS and DM-RS, etc. As used herein, time instance may be interchangeably used with slot, symbol, subframe, etc. [0109] Feature(s) associated with WTRU-assisted dynamic code book restriction are provided herein. [0110] Feature(s) described herein may be used to reduce the complexity of PMI search and CSI feedback overhead for large antenna array systems that are configured with a large grid-of-beams (GoB). [0111] The codebook subsets may be dynamically determined (e.g., based on a previously reported PMI). The WTRU may report a PMI for a first instance (e.g., from which the codebook subset for the consecutive report is determined). The WTRU may search and report PMIs from a restricted codebook subset that dynamically changes as a function of previous PMI. The size of the restriction may be based on a (e.g., preconfigured) threshold (e.g., as illustrated in FIG.2A). [0112] The WTRU may receive a configuration of CSI reporting. The configuration may include a definition of the GoB and search space (e.g., which may be the GoB or part of the GoB). At a first time, the WTRU may send a first CSI report (e.g., associated with the search space and GoB) with a first beam indicated by a precoding matrix indicator. For example, the WTRU may report a CSI at time ^^₀ with the i-th beam indicated in the PMI (e.g., indicated by ^^ _^^( ^^₀)). The first search space may be the whole GoB. The WTRU may include an indication in the CSI report at time ^^₀ that indicates application of the dynamic codebook restriction. [0113] At a second time, the WTRU may determine a second search space based on the first beam and at least one threshold. For example, at time ^^₁, the WTRU may determine a second search space and/or search space size (e.g., which is a part of GoB). For example, the WTRU may determine a second search space and/or search space size as a function of the previous CSI report (e.g., as a function of the beam indicated in the PMI of the previous CSI report) and configured thresholds (e.g., ∆₁ and ∆₂). [0114] The second search space may be smaller than the first search space and centered around the first beam. The threshold(s) may indicate at least one of a first distance and a second distance. The WTRU may determine the second search space based on the first beam and the at least one threshold by including, in the second search space, beams that are vertically located within the first distance from the first beam and horizontally located within the second distance from the first beam. The threshold(s) may include a set of search space dimensions. The WTRU may determine the set of search space dimensions based on one or more parameters and send an indication of the set of search space dimensions to the network entity. For example, the second search space may be determined to include the beams that are vertically +/- ∆₁ beams in the codebook from the location of ^^ _^^( ^^₀). The second search space may be determined to include the beams that are horizontally +/- ∆₂ beams in the codebook from the location ^^ _^^( ^^₀). In some examples, ∆₁ may be equal to ∆₂ (e.g., ∆= ∆₁= ∆₂), for example, as shown in FIG.2A. [0115] The WTRU may select a second beam from the second search space. The WTRU may search the search space for a beam (e.g., a best beam or a beam that satisfies a criteria). The WTRU may determine the beam index relative to the second search space defined by +/- ∆₁ and +/- ∆₂ (e.g., where the beam index is indicated by ^^ _^^( ^^₁)). The WTRU may report (e.g., to the gNB) the selected beam. For example, the WTRU may send an indication of the second beam to a network entity. The WTRU may indicate the beam index ^^ _^^( ^^₁) and/or a previous beam index (e.g., ^^ _^^( ^^₀)), and/or the index of the beam on which the second search space is centred. [0116] At a third time, the WTRU may determine a third search space based on the second beam and the at least one threshold. The third search space may be smaller than the first search space and centered around the second beam. For example, at time ^^₂, the WTRU may repeat the one or more of the actions for a search area centered at ^^ _^^( ^^₁). The WTRU may select a third beam from the third search space and send an indication of the third beam to the network entity. [0117] The WTRU may stay centered on ^^ _^^( ^^₀) for multiple TTIs. ∆₁ and ∆₂ may be configured per TRP. For example, the WTRU may determine a third search space based on the second beam and the at least one threshold. The third search space may be smaller than the first search space and centered around the first beam. For example, at time ^^₂, the WTRU may repeat the one or more of the actions for a search area centered at ^^ _^^ ⁽ ^^₀ ⁾. The WTRU may select a third beam from the third search space and send an indication of the third beam to the network entity. [0118] The WTRU may reset (e.g., at time ^^₀) after a configured ^^ _{^^ ^^ ^^ ^^ ^^} TTIs, or by WTRU/gNB indication. [0119] FIGs.2A and 2B illustrates an example of a WTRU searching and reporting PMIs from a restricted codebook subset. [0120] In examples (e.g., in new radio (NR)), the gNB may determine a precoder (e.g., the optimal precoder) based on CSI feedback of a codebook index. The WTRU may receive a configuration of a codebook. The codebook may be defined as a set of indices (PMIs). The PMIs may map (e.g., may each map) to a codeword (e.g., spatial filter or beam) from a set of codewords. A codeword (e.g., each codeword) may be applied across antennas at the gNB as a precoder to generate a beam. To derive a PMI (e.g., the optimal PMI), the WTRU may perform a search over indices (e.g., all indices) from the codebook. The WTRU may feedback the index (e.g., the optimal index) based on the WTRU determination. The search space (e.g., the set of indices to search from the codebook) may be preconfigured. The WTRU may receive the codebook search space through RRC. [0121] The WTRU may dynamically determine the codebook search space from a subset of the RRC configured codebook search space. The WTRU may make a first determination of the PMI based on a first codebook search space. The WTRU may iteratively update the search space for the next reporting period(s). The WTRU may report a PMI within the dynamically changing search space. [0122] A WTRU may be configured (e.g., by RRC, MAC-CE, or DCI) to determine and report a PMI (e.g., a wideband PMI or a sub-band PMI) by receiving a configuration of a RS (e.g., a CSI-RS resource configuration) with ^^₁ antenna ports in a first dimension and ^^₂ antenna ports in a second dimension. The WTRU may estimate the channel based on measurements on the RSs. The channel estimate may be used to determine the PMI. A WTRU may be configured (e.g., by RRC, MAC-CE, or DCI) with a codebook of beams, and with integer values (e.g., oversampling values O1 and O2) to oversample/increase the number of beams (e.g., oversample/increase the number of beams from ^^₁ ^^₂ to

This may result in a grid-of-beams (GoB) with a larger number of beams (e.g., ^^₁ ^^₁ ^^₂ ^^₂ number of beams). The GoB may represent the codebook from which the WTRU searches for a PMI. [0123] The parameters for the dynamic search space update may be determined by the gNB. A WTRU may perform at least one of the following actions. At time ^^₀ (e.g., where ^^₀ maybe an indicative of a time when a WTRU reports a PMI for the first time, for example, a WTRU reporting a PMI for the first time after waking up from an idle mode, or a first PMI in a configured sequence of PMIs in this reporting method), the WTRU may search the entire search space (e.g., the search space with ^^₁ ^^₁ ^^₂ ^^₂ beams in the GoB) and determine one or more beams (e.g., the ^^ _^^ℎ beam denoted as

^^( ^^₀) = 0,⋯ , ^^₁ ^^₁ ^^₂ ^^₂ − 1). The WTRU may report it in a CSI report. [0124] The bit-width of the indicator to indicate the determined beam(s) and/or PMI at ^^₀, e.g., ( ^^₀) may be a function of at least one of the following: the total number of determined beam(s); and/or the number of beams in the search space (e.g., the ^^₁ ^^₁ ^^₂ ^^₂ number of beams). For example, at ^^₀, the WTRU may report ^^ number of determined beams (e.g., ^^ ^{( ^^)} ^_{^( ^^0)} ( ^^₀), where ^^ = 1,⋯ , ^^) using ^^₁ ^^₁ ^^₂ ^^₂ number of bits. As another example, at ^^₀, the WTRU may report the ^^ number of determined beams using ^^ ^^ ^^ ^^₁ ^^₁ ^^₂ ^^_{2 2}( ^^ ) bits. [0125] At ^^₁, the WTRU may determine a second search space (e.g., that is a subset of the GoB). The second search space may be determined based on at least one of the following: as a function of the previous CSI report (e.g., as a function of the beam indicated in the PMI at time ^^₀, e.g., ^^( ^^₀)); as a function of preconfigured Δ values at ^^₁ (e.g., Δ₁( ^^₁), Δ₂( ^^₁), Δ₃( ^^₁), and/or Δ₄( ^^₁), which are described herein and define an area of the search space); and/or as a function of a beam index with the strongest coefficient level and/or amplitude level, in a PMI based on more than one beams and reported at time ^^₀ (e.g.,

− 1 and where ^^ is the index of the beam with the strongest coefficient level). [0126] For a PMI determination with a (e.g., single) beam, the second search space at ^^₁ for the second PMI report may be determined based on the index of the beam reported at ^^₀ (e.g., the ^^( ^^₀) beam) and the

values as follows:

Based on this, the WTRU may restrict its search space to the beams that are indexed relative to the previous beam report. [0127] For a PMI determination with more than one beams, the second search space at ^^₁ may be determined based on the index of the beam with the strongest coefficient level at ^^₀ (e.g., ^^ _^ ^{^} ^_{( ^^0)} ) and the Δ values at ^^₁, e.g., Δ₁( ^^₁), Δ₂( ^^₁), Δ₃( ^^₁), ^^ ^^ ^^ Δ₄( ^^₁) values as follows:

[0128] At ^^₁, a WTRU may determine beam(s) and/or a PMI based on the second search space (e.g., a PMI with more than one beams, for example, ^^ _^ ^{^^} ^_{( ^^1)} , where for example the strongest beam is denoted by ^^ _^ ^{^} ^^{^} ( ^{^^} ^_^1) = ^^_{y( ^^0)+Δ1( ^^1)}). The WTRU may determine a PMI with one beam (e.g., a PMI denoted

[0129] A WTRU may report the determined PMI in a CSI report. The bit-width of the indicator to indicate the determined beam(s) and/or PMI may be a function of at least one of the following: the total number of determined beam(s); and/or the number of beams in the second search space (e.g., the (Δ₁( ^^₁)Δ₂( ^^₁) − 1) × (Δ₃( ^^₁)Δ₄( ^^₁) − 1) number of beams in the second search space). [0130] The WTRU may report ^^ number of determined beams (e.g., ^^ ^{( ^^)} ^_{^( ^^1)} , using (Δ₁( ^^₁)Δ₂( ^^₁) − 1) × (Δ₃( ^^₁)Δ₄( ^^₁) − 1) number of bits. The WTRU may report the ^^ number of determined beams using

[0131] At ^^₂, the WTRU may update the beam index(es) reported at ^^₂ (e.g., the beam index(es) ^^( ^^₂) and/or ^^⁽ ^^₂ ⁾ becomes ^^⁽ ^^₂ ⁾ = ^^⁽ ^^₁ ⁾ + Δ₁ and/or ^^⁽ ^^₂ ⁾ = ^^⁽ ^^₁ ⁾ + Δ₁). The WTRU may reproduce/regenerate the second search space based on ^^⁽ ^^₂ ⁾ and/or i⁽ ^^₂ ⁾ and/or the Δ values (e.g., Δ₁ ⁽ ^^₂ ⁾, Δ₂ ⁽ ^^₂ ⁾, Δ₃ ⁽ ^^₂ ⁾, and/or Δ₄ ⁽ ^^₂ ⁾). The WTRU may determine and report a PMI (e.g., ^^ _{^^( ^^2)}) based on the second search space at ^^₂. [0132] At ^^ _^^, the WTRU may perform at least one of the following actions. The WTRU may determine the center beam of the nth search space at ^^ _^^, based on the beam(s) reported at ^^ _^^−1, as described herein. For a PMI reporting with more than one beam (e.g., ^^ _^ ^{^^} _^ ), the center beam of the nth search space may be the strongest beam reported at ^^ _^^−1 (e.g., the center beam of the nth search space at ^^ _^^, becomes ^^ _{^^( ^^ ^^)} = ^^ _^ ^{^} ^^{^} ( ^{^^} ^_{^ ^^−1)} ). For a PMI reporting with one beam, the center beam of the nth search space may be the beam reported at ^^ _^^−1 (e.g., the center beam of the nth search space at ^^ _^^ becomes ^^ _{^^( ^^ ^^)} = ^^ _{^^( ^^ ^^−1)}). The WTRU may determine the nth search space based on the center beams (e.g., obtained as described herein) and based on the Δ values at ^^ _^^ (e.g., Δ₁( ^^ _^^), Δ₂( ^^ _^^), Δ₃( ^^ _^^), and/or Δ₄( ^^ _^^)). The WTRU may determine and report a PMI from the nth search space. [0133] The WTRU may (e.g., dynamically) change the bit-width of the indicator to indicate the PMI may at ^^ _^^ based on one or more of the Δ values. [0134] Feature(s) associated with determining the nth search space are provided herein. [0135] At ^^ _^^, the WTRU may determine the nth search space based on the Δ value(s) at ^^ _^^ (e.g., Δ₁ ⁽ ^^ _^^ ⁾, Δ₂ ⁽ ^^ _^^ ⁾, Δ₃ ⁽ ^^ _^^ ⁾ and/or Δ₄ ⁽ ^^ _^^ ⁾) and the index of the beam(s) reported in the PMI at ^^ _^^−1 (e.g., ^^⁽ ^^ _^^−1 ⁾). If the defined/configured Δ values are such that the resulting nth search space results in violation of the boundary of the GoB with ^^₁ ^^₁ ^^₂ ^^₂ beams (e.g., ^^⁽ ^^ _^^−1 ⁾ + Δ₁ ⁽ ^^ _^^ ⁾ > ^^₁ ^^₁), the WTRU may perform at least one of the following. The WTRU may adjust the Δ value(s) so that the boundary of the GoB is not violated (e.g., a WTRU adjusts Δ₁( ^^ _^^) so that ^^( ^^ _^^−1) + Δ₁( ^^ _^^) ≤ ^^₁ ^^₁). The WTRU may report the adjusted Δ values with a higher priority in a CSI report (e.g., in part 1 of a CSI report). The WTRU may request the gNB for reconfiguration of the Δ values by sending a flag. The WTRU may request a change of the PMI reporting procedure by sending an indication to the gNB. At least one of the following may apply: requests gNB to configure the PMI reporting based on a GoB with ^^₁ ^^₁ ^^₂ ^^₂ beams for all times; requests gNB to configure the PMI reporting based on a GoB with ^^₁ ^^₁ ^^₂ ^^₂ beams at ^^ _^^+1 and PMI reporting based on a second search space (e.g., as discussed herein) starting at ^^ _^^+2. [0136] Feature(s) associated with reporting more than one beam are provided herein. [0137] A WTRU may be configured (e.g., by RRC, MAC-CS and/or DCI) to report more than one beam (e.g., report K beams for sub-band beam selection; report ^^ beams for one or more layers; and/or the like. [0138] Feature(s) associated with sub-band beam selection are provided herein. A WTRU may report more than one beams for sub-band beam selection. The WTRU may report ^^ number of beams and for a sub-band (e.g., each sub-band). The WTRU may report one out of the K number of beams. At ^^₀, the WTRU may determine (and report) K beams out of the GoB with ^^₁ ^^₁ ^^₂ ^^₂ beams. At ^^₀, the WTRU may determine (and report) one or more beams for one or more sub-bands out of the K determined beams. [0139] The center beam of the second search space at ^^₁ may be chosen based on at least one of the following: the beam reported at ^^₀ for a sub-band with a given index (e.g., a sub-band with the lowest index); the beam reported at ^^₀ for a sub-band with the highest CQI; and/or the like. [0140] Feature(s) associated with multiple beams for multiple layers are provided herein. The WTRU may be configured (e.g., by RRC, MAC-CE, and/or DCI) to report more than one beam for more than one layer. At ^^₀, the WTRU may determine and report one or more beams for one or more layers. The chosen set of beams may be orthogonal to each other. The chosen beams may be determined based on the GoB with ^^₁ ^^₁ ^^₂ ^^₂ beams. At ^^₁, the WTRU may determine the center beam of the second search space based on at least one of the following: the beam reported at ^^₀ for a layer with a given index (e.g., a layer with the lowest index); the beam reported at ^^₀ for a layer with a specific traffic type and/or MCS (e.g., a layer with the URLLC traffic and/or a layer the highest MCS, respectively); and/or the like. [0141] At ^^ _^^, a WTRU may determine a first beam within the nth search space and a second beam outside the nth search space. The first beam maybe orthogonal to the second beam. One or more beams may be orthogonal to the first beam reported at ^^ _^^. A WTRU may use an indicator to indicate one or more of the orthogonal beams at ^^ _^^. [0142] At ^^ _^^, the WTRU may divide the GoB into more than one second search spaces. For example, the WTRU may (e.g., at a third time) determine a third search space and a fourth search space. The third search space may be smaller than the first search space and may be centered around the second beam. The fourth search space may be smaller than the first search space and may be centered around the third beam. The center beams for one or more nth search spaces may be determined based on one or more beams reported at ^^ _^^−1. The one or more nth search spaces may use the same or different Δ values for one or more of the nth search spaces. [0143] The WTRU may determine the minimum WTRU processing time based on the second search space (e.g., as a function of ∆₁ and ∆₂ values). In this case, as ∆₁ and ∆₂increase, the search space may increase. The minimum WTRU processing time to measure the CSI-RS symbols may increase. The time for reporting the measured CSI-RS subsets to gNB may increase. The WTRU may report a PMI for the first-time instance from which the codebook subset for the consecutive report is determined. [0144] The Δ values may be used by the WTRU to determine the search space subset as a function of the search space, and a PMI reported in a previous time instance. The Δ values may be defined/determined/configured for the directions (e.g., each of the four directions) of the GoB (e.g., Δ₁, Δ₂, Δ₃, and/or Δ₄). The Δ values may be defined per dimension of the GoB (e.g., Δ₁ = Δ₂ and Δ₃ = Δ₄). A (e.g., single) Δ values may be defined/determined/configured (e.g., Δ₁ = Δ₂ = Δ₃ = Δ₄). The Δ values may be defined as a fixed value (e.g., the same value is used all the time). The Δ values may be configured by gNB (e.g., by RRC, MAC-CE and/or DCI) for one or more instances of the PMI reporting. [0145] Example WTRU-determined search space subset parameters are described herein. A WTRU may determine the Δ value(s) at one or more instances of the PMI determination and reporting (e.g., a WTRU determines Δ₁ ⁽ ^^ _^^ ⁾, Δ₂ ⁽ ^^ _^^ ⁾, Δ₃ ⁽ ^^ _^^ ⁾ and/or Δ₄ ⁽ ^^ _^^ ⁾ when determining the PMI at ^^ _^^). The WTRU may be configured to report a CSI in two parts (e.g., part 1 and 2) sent in different time slots. The WTRU may report the determined Δ value(s) that define the PMI search space with a higher priority (e.g., in part 1 of a CSI report). The WTRU may report the PMI as a function of the PMI search space (e.g., in part 2 of a CSI report). The WTRU may dynamically change the bit-width of the indicator for reporting PMI at ^^ _^^ (e.g., based on the determined Δ values). [0146] Search space subset parameters may be implicitly determined. The Δ value(s) (e.g., ∆₁ and ∆₂) maybe determined by the WTRU based on at least one of the following: WTRU processing capability (e.g., WTRU determines the Δ values as a function of its ability to determine the CSI, for example, as a function of the number of CPUs to determine the CSI); a CSI reference slot; MCS/number of layers; a traffic type; a codebook type; a number of antenna ports; mobility (e.g., doppler); a grant type (e.g., configured or dynamic); a number of TRPs for CJT; a number of maximum ranks per TRP; and/or the like. [0147] The WTRU may receive an association between a TCI state and codebook subsets. The association may be configured by linking a (e.g., one) TCI state to a subset from the GoB. A subset (e.g., each subset) may correspond to a set of beams. In a first example, a TCI state (e.g., each TCI state) may map to a (e.g., one) subset. In a second example, a TCI state (e.g., each TCI state) may be configured with multiple QCL type D source RS. In this case, a source RS (e.g., each source RS) may be associated with a different subset. The WTRU may determine which subset to use (e.g., as a function of which source RS is activated in the TCI state). [0148] The WTRU may receive a configuration of multiple codebook subsets. A subset (e.g., each subset) may be associated with a threshold. The threshold may be based on signal quality (e.g., RSRP), or WTRU location (e.g., distance in meter from the gNB). The WTRU may select the codebook search space subset as a function of its signal quality or location measured above the threshold. [0149] The WTRU may reset (e.g., reset the procedure described herein) if there is a misdetection of CSI. [0150] If the WTRU reports CSI, and the gNB misses detection of the CSI, the follow up CSI may be interpreted incorrectly (e.g., since the PMI at each time is relative to the search space from a previous report). The search space in the restricted codebook may be centered with the inaccurate beam. To overcome this problem, the WTRU may report an index that maps to the selected codebook subset search space ID to the gNB. The subset ID may be transmitted with a preconfigured periodicity. The WTRU may include the subset ID in ever nth CSI report. The WTRU may define the prioritization rule for dropping beam index instead of code book subset ID. The WTRU may report the sub beam index if (e.g., only if) there has been a change in the subset. [0151] The gNB may indicate to the WTRU to reset the search space or to use the same search space as used for a previous reporting (e.g., if the gNB detects a number of NACKs in HARQ above a threshold, or detects an error in the CSI report). The WTRU may receive a MAC-CE configured with a mapping of activation commands to codebook search space subsets. WTRU may modify the codebook search space subset parameters as a function of the MAC-CE activation/deactivation commands. [0152] The WTRU may be configured with a timer. The WTRU may reset the search space when the timer expires. At expiry of the timer, the WTRU may repeat the actions described herein for dynamic codebook restriction (e.g., from the beginning starting from the initially RRC configured search space). [0153] Although features and elements described above are described in particular combinations, each feature or element may be used alone without the other features and elements of the preferred embodiments, or in various combinations with or without other features and elements. [0154] Although the implementations described herein may consider 3GPP specific protocols, it is understood that the implementations described herein are not restricted to this scenario and may be applicable to other wireless systems. For example, although the solutions described herein consider LTE, LTE-A, New Radio (NR) or 5G specific protocols, it is understood that the solutions described herein are not restricted to this scenario and are applicable to other wireless systems as well. For example, while the system has been described with reference to a 3GPP, 5G, and/or NR network layer, the envisioned embodiments extend beyond implementations using a particular network layer technology. Likewise, the potential implementations extend to all types of service layer architectures, systems, and embodiments. The techniques described herein may be applied independently and/or used in combination with other resource configuration techniques. [0155] The processes described herein may be implemented in a computer program, software, and/or firmware incorporated in a computer-readable medium for execution by a computer and/or processor. Examples of computer-readable media include, but are not limited to, electronic signals (transmitted over wired and/or wireless connections) and/or computer-readable storage media. Examples of computer- readable storage media include, but are not limited to, a read only memory (ROM), a random access memory (RAM), a register, cache memory, semiconductor memory devices, magnetic media such as, but not limited to, internal hard disks and removable disks, magneto-optical media, and/or optical media such as compact disc (CD)-ROM disks, and/or digital versatile disks (DVDs). A processor in association with software may be used to implement a radio frequency transceiver for use in a WTRU, terminal, base station, RNC, and/or any host computer. [0156] It is understood that the entities performing the processes described herein may be logical entities that may be implemented in the form of software (e.g., computer-executable instructions) stored in a memory of, and executing on a processor of, a mobile device, network node or computer system. That is, the processes may be implemented in the form of software (e.g., computer-executable instructions) stored in a memory of a mobile device and/or network node, such as the node or computer system, which computer executable instructions, when executed by a processor of the node, perform the processes discussed. It is also understood that any transmitting and receiving processes illustrated in figures may be performed by communication circuitry of the node under control of the processor of the node and the computer-executable instructions (e.g., software) that it executes. [0157] The various techniques described herein may be implemented in connection with hardware or software or, where appropriate, with a combination of both. Thus, the implementations and apparatus of the subject matter described herein, or certain aspects or portions thereof, may take the form of program code (e.g., instructions) embodied in tangible media including any other machine-readable storage medium wherein, when the program code is loaded into and executed by a machine, such as a computer, the machine becomes an apparatus for practicing the subject matter described herein. In the case where program code is stored on media, it may be the case that the program code in question is stored on one or more media that collectively perform the actions in question, which is to say that the one or more media taken together contain code to perform the actions, but that – in the case where there is more than one single medium – there is no requirement that any particular part of the code be stored on any particular medium. In the case of program code execution on programmable devices, the computing device generally includes a processor, a storage medium readable by the processor (including volatile and non-volatile memory and/or storage elements), at least one input device, and at least one output device. One or more programs that may implement or utilize the processes described in connection with the subject matter described herein, e.g., through the use of an API, reusable controls, or the like. Such programs are preferably implemented in a high level procedural or object oriented programming language to communicate with a computer system. However, the program(s) can be implemented in assembly or machine language, if desired. In any case, the language may be a compiled or interpreted language, and combined with hardware implementations. [0158] Although example embodiments may refer to utilizing aspects of the subject matter described herein in the context of one or more stand-alone computing systems, the subject matter described herein is not so limited, but rather may be implemented in connection with any computing environment, such as a network or distributed computing environment. Still further, aspects of the subject matter described herein may be implemented in or across a plurality of processing chips or devices, and storage may similarly be affected across a plurality of devices. Such devices might include personal computers, network servers, handheld devices, supercomputers, or computers integrated into other systems such as automobiles and airplanes. [0159] In describing preferred embodiments of the subject matter of the present disclosure, as illustrated in the Figures, specific terminology is employed for the sake of clarity. The claimed subject matter, however, is not intended to be limited to the specific terminology so selected, and it is to be understood that each specific element includes all technical equivalents that operate in a similar manner to accomplish a similar purpose.

Claims

CLAIMS What is Claimed: 1. A wireless transmit/receive unit (WTRU) comprising: a processor configured to: at a first time, send a first channel state information (CSI) report with a first beam indicated by a precoding matrix indicator, wherein the first CSI report is associated with a first search space comprising a grid of beams (GoB); at a second time, determine a second search space based on the first beam and at least one threshold, wherein the second search space is smaller than the first search space and centered around the first beam; select a second beam from the second search space; and send an indication of the second beam to a network entity.

2. The WTRU of claim 1, wherein the processor is further configured to: at a third time, determine a third search space based on the second beam and the at least one threshold, wherein the third search space is smaller than the first search space and centered around the second beam; select a third beam from the third search space; and send an indication of the third beam to the network entity.

3. The WTRU of claim 1, wherein the at least one threshold comprises a first set of search space dimensions, and the processor is further configured to: at a third time, determine a third search space based on the first beam and a second set of search space dimensions, wherein the third search space is smaller than the first search space and centered around the first beam; select a third beam from the third search space; and send an indication of the third beam to the network entity.

4. The WTRU of claim 1, wherein the at least one threshold indicates at least one of a first distance and a second distance, and the processor being configured to determine the second search space based on the first beam and the at least one threshold comprises the processor being configured to include, in the second search space, beams that are vertically located within the first distance from the first beam and horizontally located within the second distance from the first beam.

5. The WTRU of claim 1, wherein the processor being configured to select the second beam from the second search space comprises the processor being configured to: determine a first cost associated with a third beam in the second search space, and a second cost associated with a fourth beam in the second search space; and select the third beam or the fourth beam, as the second beam, based on the first cost and the second cost.

6. The WTRU of claim 1, wherein the processor is further configured to: select a third beam from the second search space; send an indication of the third beam to a network entity; at a third time, determine a third search space and a fourth search space, wherein the third search space is smaller than the first search space and centered around the second beam, and the fourth search space is smaller than the first search space and centered around the third beam.

7. The WTRU of claim 1, wherein the at least one threshold comprises a set of search space dimensions, and the processor is further configured to: determine the set of search space dimensions based on one or more parameters; and send an indication of the set of search space dimensions to the network entity.

8. The WTRU of claim 1, wherein the first CSI report comprises an indication that dynamic codebook restrictions are applicable.

9. A method, performed by a wireless transmit/receive unit (WTRU), the method comprising: at a first time, sending a first channel state information (CSI) report with a first beam indicated by a precoding matrix indicator, wherein the first CSI report is associated with a first search space comprising a grid of beams (GoB); at a second time, determining a second search space based on the first beam and at least one threshold, wherein the second search space is smaller than the first search space and centered around the first beam; selecting a second beam from the second search space; and sending an indication of the second beam to a network entity.

10. The method of claim 9, wherein the method further comprises: at a third time, determining a third search space based on the second beam and the at least one threshold, wherein the third search space is smaller than the first search space and centered around the second beam; selecting a third beam from the third search space; and sending an indication of the third beam to the network entity.

11. The method of claim 9, wherein the at least one threshold comprises a first set of search space dimensions, and the method further comprises: at a third time, determining a third search space based on the first beam and a second set of search space dimensions, wherein the third search space is smaller than the first search space and centered around the first beam; selecting a third beam from the third search space; and sending an indication of the third beam to the network entity.

12. The method of claim 9, wherein the at least one threshold indicates at least one of a first distance and a second distance, and determining the second search space based on the first beam and the at least one threshold comprises including, in the second search space, beams that are vertically located within the first distance from the first beam and horizontally located within the second distance from the first beam.

13. The method of claim 9, wherein selecting the second beam from the second search space comprises: determining a first cost associated with a third beam in the second search space, and a second cost associated with a fourth beam in the second search space; and selecting the third beam or the fourth beam, as the second beam, based on the first cost and the second cost.

14. The method of claim 9, wherein the method further comprises: selecting a third beam from the second search space; sending an indication of the third beam to a network entity; at a third time, determining a third search space and a fourth search space, wherein the third search space is smaller than the first search space and centered around the second beam, and the fourth search space is smaller than the first search space and centered around the third beam.

15. The method of claim 9, wherein the at least one threshold comprises a set of search space dimensions, and the method further comprises: determining the set of search space dimensions based on one or more parameters; and sending an indication of the set of search space dimensions to the network entity.

16. The method of claim 9, wherein the first CSI report comprises an indication that dynamic codebook restrictions are applicable.