Methods and apparatuses for channel state information reporting for hybrid beamforming

Abstract

A method may be implemented by a wireless transmit / receive unit (WTRU), and may include receiving configuration information. The configuration information may indicate one or more of a plurality of channel state information (CSI) reference signal (RS) resources in a CSI-RS resource set. The configuration information may indicate a target performance requirement. One or more CSI-RS resources may be selected from the plurality of CSI-RS resources based on characteristics of the one or more CSI-RS resources and the target performance requirement. A CSI report may be sent. The CSI report may include an indication of the one or more selected CSI-RS resources.

Description

METHODS AND APPARATUSES FOR CHANNEL STATE INFORMATION REPORTING FOR HYBRID BEAMFORMINGCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of United States Provisional Application No. 63 / 570,504, filed on March 27, 2024, the entire contents of which is incorporated herein by reference in its entirety.BACKGROUND

[0002] 5G new radio (NR) supports analog beamforming of channel state information (CSI) reference signal (RS) (CSI-RS) resources. For analog beamforming of CSI-RS resources, a resource set can have up to eight CSI-RS resources with up to eight CSI-RS antenna ports in each CSI-RS resource, with a maximum of 32 CSI-RS antenna ports. 5G NR also supports two CSI-RS resources in a CSI-RS resource set with 16 CSI-RS antenna ports in each CSI-RS resource. Moreover, 5G NR supports determining and reporting a CSI based on a single CSI-RS resource in the CSI-RS resource set.SUMMARY

[0003] A wireless transmit / receive unit (WTRU) may be described herein. The WTRU may include a processor. The processor may be configured to receive configuration information. The configuration information may indicate one or more of a plurality of channel state information (CSI) reference signal (RS) resources in a CSI-RS resource set. The configuration information may indicate a target performance requirement. The processor may be configured to select one or more CSI-RS resources from the plurality of CSI-RS resources based on characteristics of the one or more CSI-RS resources and the target performance requirement. The processor may be configured to send a CSI report. The CSI report may include an indication of the one or more selected CSI-RS resources.

[0004] The target performance requirement may include one or more of a target reference signal received power (RSRP) value, a target rank value, or a target channel quality indicator (CQI) value.

[0005] The characteristics of the one or more CSI-RS resources may include an aggregated RSRP value of the one or more CSI-RS resources. The processor may be configured to select the one or more of CSI-RS resources based on the aggregated RSRP value being greater than or equal to the target RSRP value.

[0006] The characteristics of the one or more CSI-RS resources may include an aggregated CQI value of the one or more CSI-RS resources. The processor may be configured to select the one or more CSI-RS resources based on the aggregated CQI value being greater than or equal to the target CQI value.

[0007] The characteristics of the one or more CSI-RS resources may include an aggregated rank value of the one or more CSI-RS resources. The processor may be configured to select the one or more CSI-RS resources based on the aggregated rank value being greater than or equal to the target rank value.

[0008] The processor may be configured to receive a CSI-RS resource selection criterion. The CSI-RS resource selection criterion may include one or more of a target reference signal received power (RSRP) value, a target rank value, or a target channel quality indicator (CQI) value. The processor may be configured to select the one or more CSI-RS resources from the plurality of CSI-RS resources based on the CSI-RS resource selection criterion.

[0009] The processor may be configured to send the CSI report based on a priority level associated with the CSI report. The processor may be configured to determine the priority level based on one or more of an RSRP value, a rank value, or a CQI value of the CSI report.

[0010] The one or more CSI-RS resources may include a minimum number of CSI-RS resources capable of achieving one or more of a maximum aggregated RSRP value that is greater than or equal to a target reference signal received power (RSRP) value, a maximum aggregated channel quality indicator (CQI) value that is greater than or equal to a target CQI value, or a maximum aggregated rank value that is greater than or equal to a target rank value.

[0011] The indication of the one or more CSI-RS resources may include an indication of one or more of a respective rank value for each of the one or more CSI-RS resources, a respective channel quality indicator (CQI) value for each of the one or more CSI-RS resources, a respective precoding matrix indicator (PM I) for each of the one or more CSI-RS resources, or a respective reference signal received power (RSRP) value for each of the one or more CSI-RS resources.

[0012] The indication of the one or more CSI-RS resources may include an indication of one or more of an aggregated rank value for the one or more CSI-RS resources, an aggregated channel quality indicator (CQI) value for the one or more CSI-RS resources, an aggregated precoding matrix indicator (PMI) for the one or more CSI-RS resources, or an aggregated reference signal received power (RSRP) value for the one or more CSI-RS resources.

[0013] A method may be implemented by a wireless transmit / receive unit (WTRU), and may include receiving configuration information. The configuration information may indicate one or more of a plurality of channel state information (CSI) reference signal (RS) resources in a CSI-RS resource set. The configuration information may indicate a target performance requirement. One or more CSI-RS resources may be selected from the plurality of CSI-RS resources based on characteristics of the one or more CSI- RS resources and the target performance requirement. A CSI report may be sent. The CSI report may include an indication of the one or more selected CSI-RS resources.

[0014] The target performance requirement may include one or more of a target reference signal received power (RSRP) value, a target rank value, or a target channel quality indicator (CQI) value.

[0015] The characteristics of the one or more CSI-RS resources may include an aggregated RSRP value of the one or more CSI-RS resources. The one or more CSI-RS resources may be selected based on the aggregate RSRP value being greater than or equal to the target RSRP value.

[0016] The characteristics of the one or more CSI-RS resources may include an aggregated CQI value of the one or more CSI-RS resources. The selection of the one or more CSI-RS resources may be based on the aggregated CQI value being greater than or equal to the target CQI value.

[0017] The characteristics of the one or more CSI-RS resources may include an aggregated rank value of the one or more CSI-RS resources. The selection of the one or more CSI-RS resources may be based on the aggregated rank value being greater than or equal to the target rank value.

[0018] The method may include receiving a CSI-RS resource selection criterion. The CSI-RS resource selection criterion may include one or more of a target reference signal received power (RSRP) value, a target rank value, or a target channel quality indicator (CQI) value. One or more CSI-RS resources may be selected from the plurality of CSI-RS resources based on the CSI-RS resource selection criterion.

[0019] The method may include sending the CSI report based on a priority level associated with the CSI report. The priority level may be determined based on one or more of an RSRP value, a rank value, or a CQI value of the CSI report

[0020] The one or more CSI-RS resources may include a minimum number of CSI-RS resources capable of achieving one or more of a maximum aggregated reference signal received power (RSRP) value that is greater than or equal to a target RSRP value, a maximum aggregated channel quality indicator (CQI) value that is greater than or equal to a target CQI value, or a maximum aggregated rank value that is greater than or equal to a target rank value.

[0021] The indication of the one or more CSI-RS resources may include an indication of one or more of a respective rank value for each of the one or more CSI-RS resources, a respective channel quality indicator (CQI) value for each of the one or more CSI-RS resources, a respective precoding matrix indicator (PM I) for each of the one or more CSI-RS resources, or a respective reference signal received power (RSRP) value for each of the one or more CSI-RS resources.

[0022] The indication of the one or more CSI-RS resources may include an indication of one or more of an aggregated rank value for the one or more CSI-RS resources, an aggregated channel quality indicator (CQI) value for the one or more CSI-RS resources, an aggregated precoding matrix indicator (PM I) for the one or more CSI-RS resources, or an aggregated reference signal received power (RSRP) value for the one or more CSI-RS resources.

[0023] Examples described herein may relate to communication networks, wireless and / or wired. For example, one or more embodiments disclosed herein may be related to methods and apparatus for channel state information (CSI) reporting for hybrid beamforming and / or CSI reference signal (RS) (CSI-RS) resources selection in wireless communications. In some examples, CSI-RS resource indicator (CRI) may be used for CSI reporting and / or CSI-RS resources selection.BRIEF DESCRIPTION OF THE DRAWINGS

[0024] A more detailed understanding may be had from the detailed description below, given by way of example in conjunction with drawings appended hereto Figures in such drawings, like the detailed description, are examples. As such, the Figures (FIGs.) and the detailed description are not to be considered limiting, and other equally effective examples are possible and likely. Furthermore, like reference numerals ("ref.") in the FIGs. indicate like elements, and wherein:

[0025] FIG. 1A is a system diagram illustrating an example communications system in which one or more disclosed embodiments may be implemented;

[0026] FIG. 1 B 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;

[0027] 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;

[0028] FIG. 1 D 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; and

[0029] FIG. 2 is a diagram illustrating an example procedure for channel state information (CSI) reporting for hybrid beamforming according to an embodiment.DETAILED DESCRIPTION

[0030] In the following detailed description, numerous specific details are set forth to provide a thorough understanding of embodiments and / or examples disclosed herein. However, it will be understood that such embodiments and examples may be practiced without some or all of the specific details set forth herein. In other instances, well-known methods, procedures, components and circuits have not been described in detail, so as not to obscure the following description. Further, embodiments and examples not specifically described herein may be practiced in lieu of, or in combination with, the embodiments and other examples described, disclosed or otherwise provided explicitly, implicitly and / or inherently (collectively "provided") herein. Although various embodiments are described and / or claimed herein in which an apparatus, system, device, etc. and / or any element thereof carries out an operation, process, algorithm, function, etc. and / orany portion thereof, it is to be understood that any embodiments described and / or claimed herein assume that any apparatus, system, device, etc. and / or any element thereof is configured to carry out any operation, process, algorithm, function, etc. and / or any portion thereof.

[0031] The methods, apparatuses and systems provided herein are well-suited for communications involving both wired and wireless networks. An overview of various types of wireless devices and infrastructure is provided with respect to FIGs. 1A-1 D, where various elements of the network may utilize, perform, be arranged in accordance with and / or be adapted and / or configured for the methods, apparatuses and systems provided herein.

[0032] FIG. 1A is a system 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 (ZT) unique-word (UW) discreet Fourier transform (DFT) spread OFDM (ZT UW DTS-s OFDM), unique word OFDM (UW-OFDM), resource block-filtered OFDM, filter bank multicarrier (FBMC), and the like.

[0033] As shown in FIG. 1A, the communications system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, a radio access network (RAN) 104 / 113, a core network (CN) 106 / 115, a public switched telephone network (PSTN) 108, the Internet 110, and other networks 112, 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 (or be) a user equipment (UE), 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-Fl device, an Internet of Things (loT) 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 UE.

[0034] 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, e.g., to facilitate access to one or more communication networks, such as the CN 106 / 115, the Internet 110, and / or the networks 112. By way of example, the base stations 114a, 114b may be any of a base transceiver station (BTS), a Node-B (NB), an eNode-B (eNB), a Home Node-B (HNB), a Home eNode-B (HeNB), a gNode-B (gNB), a NR Node-B (NR NB), a site controller, an access point (AR), 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.

[0035] 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 an 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 or any sector of the cell. For example, beamforming may be used to transmit and / or receive signals in desired spatial directions.

[0036] 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).

[0037] 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 116 using wideband CDMA (WCDMA). WCDMA may include communication protocols such as High-Speed Packet Access (HSPA) and / or Evolved HSPA (HSPA+). HSPA may include High-Speed Downlink Packet Access (HSDPA) and / or High-Speed Uplink Packet Access (HSUPA).

[0038] 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).

[0039] 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).

[0040] 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 ., an eNB and a gNB).

[0041] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement radio technologies such as IEEE 802.11 (i.e., Wireless Fidelity (Wi-Fi), IEEE 802.16 (i.e., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile communications (GSM), Enhanced Data rates for GSM Evolution (EDGE), GSM EDGE (GERAN), and the like.

[0042] 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 an 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 an 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 any of a small cell, 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.

[0043] 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 an NR radio technology, the CN 106 / 115 may also be in communication with another RAN (not shown) employing any of a GSM, UMTS, CDMA 2000, WiMAX, E-UTRA, or Wi-Fi radio technology.

[0044] The CN 106 / 115 may also serve as a gateway for the WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the Internet 110, and / or other networks 112. The PSTN 108 may include 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 / 114 or a different RAT.

[0045] 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.

[0046] FIG. 1 B is a system diagram illustrating an example WTRU 102. As shown in FIG. 1 B, 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 elements / peripherals 138, among others. It will be appreciated that the WTRU 102 may include any subcombination of the foregoing elements while remaining consistent with an embodiment.

[0047] 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 integratedcircuit (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. 1 B 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, e.g., in an electronic package or chip.

[0048] 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 an 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 an 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.

[0049] 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. For example, the WTRU 102 may employ MIMO technology. Thus, in an 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.

[0050] 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.

[0051] 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 118may 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).

[0052] 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.

[0053] 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 locationdetermination method while remaining consistent with an embodiment.

[0054] The processor 118 may further be coupled to other elements / peripherals 138, which may include one or more software and / or hardware modules / units that provide additional features, functionality and / or wired or wireless connectivity. For example, the elements / peripherals 138 may include an accelerometer, an e-compass, a satellite transceiver, a digital camera (e.g., 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 elements / 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.

[0055] 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 uplink (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 WTRU 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 uplink (e.g., for transmission) or the downlink (e.g., for reception)).

[0056] 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, and 102c over the air interface 116. The RAN 104 may also be in communication with the CN 106.

[0057] 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 an 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 receive wireless signals from, the WTRU 102a.

[0058] Each of the eNode-Bs 160a, 160b, and 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the uplink (UL) and / or downlink (DL), and the like. As shown in FIG. 1 C, the eNode-Bs 160a, 160b, 160c may communicate with one another over an X2 interface.

[0059] 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 (PGW) 166. While each of the foregoing elements are depicted as part of the CN 106, it will be appreciated that any one of these elements may be owned and / or operated by an entity other than the CN operator.

[0060] The MME 162 may be connected to each of the eNode-Bs 160a, 160b, and 160c 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.

[0061] 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.

[0062] 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.

[0063] 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, tofacilitate 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.

[0064] Although the WTRU is described in FIGs. 1A-1 D 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.

[0065] In representative embodiments, the other network 112 may be a WLAN.

[0066] 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 into 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.

[0067] When using the 802.11 ac 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.

[0068] 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.

[0069] Very high throughput (VHT) STAs may support 20 MHz, 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 a medium access control (MAC) layer, entity, etc.

[0070] Sub 1 GHz modes of operation are supported by 802.11 af and 802.11 ah. The channel operating bandwidths, and carriers, are reduced in 802.11 af and 802.11 ah relative to those used in 802.11n, and 802.11ac. 802.11 af supports 5 MHz, 10 MHz and 20 MHz bandwidths in the TV white space (TVWS) spectrum, and 802.11 ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths using non-TVWS spectrum. According to a representative embodiment, 802.11 ah may support meter type control / machine- type communications (MTC), 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).

[0071] WLAN systems, which may support multiple channels, and channel bandwidths, such as 802.11 n, 802.11 ac, 802.11 af, and 802.11 ah, 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 802.11 ah, 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 AF, 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.

[0072] In the United States, the available frequency bands, which may be used by 802.11 ah, 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 802.11 ah is 6 MHz to 26 MHz depending on the country code.

[0073] FIG. 1 D 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.

[0074] 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 an embodiment, the gNBs 180a, 180b, 180c may implement MIMO technology. For example, gNBs 180a, 180b may utilize beamforming to transmit signals to and / or receive signals from the WTRUs 102a, 102b, 102c. 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).

[0075] The WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using transmissions associated with a scalable numerology. For example, OFDM symbol spacing and / or OFDM subcarrier spacing may vary for different transmissions, different cells, and / or different portions of the wireless transmission spectrum. The WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using subframe or transmission time intervals (TTIs) of various or scalable lengths (e.g., including a varying number of OFDM symbols and / or lasting varying lengths of absolute time).

[0076] 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 communicatewith / 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.

[0077] 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 functions (UPFs) 184a, 184b, routing of control plane information towards access and mobility management functions (AMFs) 182a, 182b, and the like. As shown in FIG. 1D, the gNBs 180a, 180b, 180c may communicate with one another over an Xn interface.

[0078] The CN 115 shown in FIG. 1 D may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one session management function (SMF) 183a, 183b, and at least one 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.

[0079] 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 protocol data unit (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, e.g., 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 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 Wi-Fi.

[0080] 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 UE IP address, managing PDU sessions, controlling policy enforcement and QoS, providingdownlink data notifications, and the like. A PDU session type may be IP-based, non-IP based, Ethernetbased, and the like.

[0081] 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, e.g., 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.

[0082] 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 an 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.

[0083] In view of FIGs. 1 A-1 D, and the corresponding description of FIGs. 1 A-1 D, one or more, or all, of the functions described herein with regard to any of: WTRUs 102a-d, base stations 114a-b, eNode-Bs 160a-c, MME 162, SGW 164, PGW 166, gNBs 180a-c, AMFs 182a-b, UPFs 184a-b, SMFs 183a-b, DNs 185a-b, and / or any other element(s) / device(s) described herein, may be performed by one or more emulation elements / 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.

[0084] 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.

[0085] 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.

[0086] Hereinafter, the terms "a” and “an” and similar phrases may be interpreted as “one or more” and / or “at least one.” Similarly, any term that ends with the suffix “(s)” may be interpreted as “one or more” and / or “at least one.” The term “may” may be interpreted as “may, for example” and / or “for example.”

[0087] The following terminology may be used and can be assumed throughout this document.

[0088] A codebook may be a set of discrete Fourier transform (DFT)-beams, codewords, basis-beams, two-dimensional (2D) basis beams, and / or 2D vectors for selection of a precoding matrix indicator (PMI). A DFT-beam may be a vector of complex numbers, which may additionally and / or alternatively be termed a basis-beam, codeword, and / or PMI. A PMI may be a set of one or more DFT-beams, basis-beams, and / or codewords.

[0089] DFT-oversampling may be an integer number that may be used to oversample and / or increase the number of DFT-beams, basis-beams, and / or codewords in a codebook. Channel state information (CSI) may include one or more of the following: channel quality index (CQI), rank indicator (Rl), PMI, a Layer 1 (L1) channel measurement (e.g., reference signal received power (RSRP) such as L1-RSRP and / or signal- to-interference-plus-noise ratio (SINR)), CSI-reference signal (CSI-RS) resource indicator (CRI), synchronization signal / physical broadcast channel (SS / PBCH) block resource indicator (SSBRI), and / or layer indicator (LI). CSI may also include any other measurement quantity determined by the wireless transmit / receive unit (WTRU) from the configured CSI-RS and / or SS / PBCH block. A WTRU may report a subset of CSI components, where CSI components may correspond to at least a CRI, an SSBRI, an indication of a panel used for reception at the WTRU (e.g., a panel identity and / or a group identity), and / or measurements such as L1-RSRP and / or L1-SINR taken from SS / PBCH and / or CSI-RS (e.g., CRI-RSRP, CRI-SINR, SSB-lndex-RSRP, and / or SSB-lndex-SINR). Additionally, and / or alternatively, CSI components may include at least an Rl, CQI, PMI, LI, and / or any similar measurement.

[0090] A CSI-RS may be a reference signal used for sounding one or more downlink (DL) channels. A CRI may be an index of a CSI-RS resource in a CSI-RS resource set. CSI-RS ports may be singlepolarized and / or dual-polarized antenna ports used for transmission of CSI-RS for DL channel sounding. A CSI resource may be time and / or frequency resources used for transmission of the CSI-RS from a number of CSI-RS ports. A CSI resource set may be a collection of one or more CSI resources.

[0091] Recent advances in device capabilities and the introduction of new frequency bands may enable embedding a larger number of antenna elements with enhanced processing. However, the Fifth Generation New Radio (5G NR) specification may offer support for a limited number of antenna ports. Extending thenumber of channel state information reference signal (CSI-RS) antenna ports and / or determining and reporting channel state information (CSI) based on more than one CSI-RS resource may provide benefits in coverage, throughput, and / or multi-user multiple-input multiple-output (MIMO) user pairing. Reporting a CSI for each CSI-RS resource, however, may introduce unnecessary complexity and / or feedback overhead. Reporting a CSI for a subset of CSI-RS resources may reduce complexity and / or feedback overhead. The selection of a subset of CSI-RS resources and reporting CSI for a subset of CSI-RS resources may introduce additional challenges. Therefore, new and / or enhanced methods and procedures may be utilized to address selection of a subset of CSI-RS resources from a CSI-RS resource set, a determination of a CSI on the selected subset of CSI-RS resources, and / or managing and / or handling the CSI reporting for multiple CSI-RS resources.

[0092] In examples, one or more procedures may be introduced for selecting a subset of CSI-RS resources from a CSI-RS resource set and determining a CSI on the selected subset of CSI-RS resources. For example, a wireless transmit / receive unit (WTRU) may receive a CSI-RS configuration that includes indications for one or more of the following: two or more CSI-RS resources in a CSI-RS resource set and / or a target performance requirement (e.g., a target reference signal received power (RSRP) value, a target rank value, and / or a target channel quality index (CQI) value).

[0093] In examples, the WTRU may receive a plurality of CSI-RS resources and may determine and / or select a subset (e.g., one or more) of CSI-RS resources from the CSI-RS resource set. One or more of the following may apply when selecting the subset of CSI-RS resources. In an example, the aggregate RSRP value (e.g., summation of the RSRP values) of the CSI-RS resources in the determined subset of CSI-RS resources may be greater than or equal to a target RSRP value. For example, a CSI-RS resource set may include four CSI-RS resources, where a first CSI-RS resource may have an RSRP value of 0 d B, a second CSI-RS resource may have an RSRP value of 1 dB, a third CSI-RS resource may have an RSRP value of 2 dB, and a fourth CSI-RS resource may have an RSRP value of 3 dB. If the target RSRP is 5 dB, then the selected subset of CSI-RS resources may include only the third and fourth CSI-RS resources, which may have an aggregate RSRP value equal to 5 dB.

[0094] In an example, the aggregate CQI value (e.g., summation of the CQI values) of the CSI-RS resources in the determined subset of CSI-RS resources may be greater than or equal to a target CQI value. For example, a first CSI-RS resource may have a CQI value of 0, a second CSI-RS resource may have a CQI value of 1 , a third CSI-RS resource may have a CQI value of 2, and a fourth CSI-RS resource may have a CQI value of 3. If the target CQI value is 6, then the selected subset of CSI-RS resources may include only the second, third, and fourth CSI-RS resources, which may have an aggregate CQI value equal to 6.

[0095] In an example, the aggregate rank value (e.g., summation of the rank values) of the CSI-RS resources in the determined subset of CSI-RS resources may be greater than or equal to a target rank value. For example, a first CSI-RS resource may have a rank value of 2, a second CSI-RS resource may have a rank value of 3, a third CSI-RS resource may have a rank value of 5, and a fourth CSI-RS resource may have a rank value of 6. If the target rank is 10, then the selected subset of CSI-RS resources may include only the third and fourth CSI-RS resources, which may have an aggregated rank value equal to 11.

[0096] In an example, the determined subset may include a minimum number of CSI-RS resources that may achieve the maximum aggregated RSRP value, the maximum aggregated CQI value, and / or the maximum aggregated rank value that may be greater than or equal to a target RSRP value, a target CQI value, and / or a target rank value. For example, a first CSI-RS resource may have a rank value of 2, a second CSI-RS resource may have a rank value of 3, a third CSI-RS resource may have a rank value of 4, and a fourth CSI-RS resource may have a rank value of 5. If the target rank is 7, then the selected subset of CSI-RS resources may include only the third and fourth CSI-RS resources, which may have an aggregated rank value equal to 9.

[0097] In an example, the WTRU may determine Class-A and / or Class-B CSI (e.g., rank, PM I, and / or CQI) based on the CSI-RS resources included in the selected subset of CSI-RS resources. For Class-A CSI, the WTRU may determine a CSI for each of the CSI-RS resources in the determined subset of CSI- RS resources. For example, if the selected subset of CSI-RS resources includes two CSI-RS resources, the WTRU may determine a first CSI for the first CSI-RS resource and a second CSI for the second CSI- RS resource. In an example, the WTRU may determine one rank value, one PM I, and one CQI value for each of the CSI-RS resources in the selected subset of CSI-RS resources.

[0098] For Class-B CSI, the WTRU may determine a single CSI for all the CSI-RS resources in the determined subset of CSI-RS resources. For example, if the selected subset of CSI-RS resources includes two CSI-RS resources, the WTRU may determine a single CSI based on both CSI-RS resources in the selected subset of CSI-RS resources. In an example, the WTRU may determine one rank value, one PMI, and one CQI value based on all CSI-RS resources in the selected subset of CSI-RS resources.

[0099] In an example, the WTRU may send a CSI report that may include information (e.g., an indication) of the CSI-RS resources included in the subset of CSI-RS resources. For Class-A (e.g., one CSI for each selected CSI-RS resource), the information may include and / or indicate one or more of the following: an indication of the rank value for each of the selected CSI-RS resources, an indication of the CQI value for each of the selected CSI-RS resources, an indication of the PMI for each of the selected CSI- RS resources, and / or an indication of the RSRP value for each of the selected CSI-RS resources.

[0100] For Class-B (e.g., one CSI for all selected CSI-RS resources and / or CRIs), the information may include and / or indicate one or more of the following: an indication of a single rank value for all the selectedCSI-RS resources, an indication of a single CQI value for all the selected CSI-RS resources, an indication of a single PM I for all the selected CSI-RS resources, and / or an indication of a single RSRP value for all the selected CSI-RS resources.

[0101] Representative procedures for CSI-RS resource selection may be described herein. For instance, CSI configurations may be described. In examples, a wireless transmit / receive unit (WTRU) may receive a channel state information reference signal (CSI-RS) configuration that may include indications for one or more of the following: two or more CSI-RS resources in a CSI-RS resource set and / or a CSI-RS resource selection criteria based on at least one of the following.

[0102] For Type-A, the WTRU may receive a target reference signal received power (RSRP), a target rank, a target channel quality index (CQI), or a target RSRP, a target rank, and a target CQI. For Type-B, the WTRU may receive an RSRP threshold and an RSRP offset, a rank threshold and a rank offset, and / or a CQI threshold and a CQI offset associated with one or more CSI-RS resource indicators (CRIs). For Type-C, the WTRU may autonomously determine (e.g., select) CSI-RS resources in a CSI-RS resource set based on the available uplink resource for CSI reporting.

[0103] In an example, the WTRU may receive a CSI-RS configuration that may include an indication for a Class-A CSI and / or a Class-B CSI. For example, the WTRU may be configured to determine and report a Class-A and / or a Class-B CSI based on the determined (e.g., selected) CSI-RS resources in the CSI-RS resource set

[0104] In examples, the WTRU may receive a plurality of CSI-RS resources and may perform one or more operations. In one embodiment, the WTRU may determine (e.g., select) a subset of CSI-RS resources based on one or more of the following.

[0105] For Type-A, the WTRU may determine (e.g., select) a subset (e.g., one or more) of CSI-RS resources from the CSI-RS resource set, and one or more of the following may apply when selecting the subset of CSI-RS resources.

[0106] In an example, the aggregate RSRP value (e.g., summation of the RSRP values) of the CSI-RS resources in the determined subset of CSI-RS resources may be greater than or equal to a target RSRP value. For example, a CSI-RS resource set may include four CSI-RS resources, where a first CSI-RS resource may have an RSRP value of 0 dB, a second CSI-RS resource may have an RSRP value of 1 dB, a third CSI-RS resource may have an RSRP value of 2 dB, and a fourth CSI-RS resource may have an RSRP value of 3 dB. If the target RSRP is 5 dB, then the selected subset of CSI-RS resources may include only the third and fourth CSI-RS resources, which may have an aggregate RSRP value equal to 5 dB.

[0107] In another example, the aggregate CQI value (e.g., summation of the CQI values) of the CSI-RS resources in the determined subset of CSI-RS resources may be greater than or equal to a target CQI value. For example, a first CSI-RS resource may have a CQI value of 0, a second CSI-RS resource mayhave a CQI value of 1 , a third CSI-RS resource may have a CQI value of 2, and a fourth CSI-RS resource may have a CQI value of 3. If the target CQI value is 6, then the selected subset of CSI-RS resources may include only the second, third, and fourth CSI-RS resources, which may have an aggregate CQI value equal to 6.

[0108] In an example, the aggregate rank value (e.g., summation of the rank values) of the CSI-RS resources in the determined subset of CSI-RS resources may be greater than or equal to a target rank value. For example, a first CSI-RS resource may have a rank value of 2, a second CSI-RS resource may have a rank value of 3, a third CSI-RS resource may have a rank value of 5, and a fourth CSI-RS resource may have a rank value of 6. If the target rank is 10, then the selected subset of CSI-RS resources may include only the third and fourth CSI-RS resources, which may have an aggregated rank value equal to 11.

[0109] In another example, the determined subset may include a minimum number of CSI-RS resources that may achieve the maximum aggregated RSRP value, the maximum aggregated CQI value, and / or the maximum aggregated rank value that may be greater than or equal to a target RSRP value, a target CQI value, and / or a target rank value.

[0110] For example, a first CSI-RS resource may have a rank value of 2, a second CSI-RS resource may have a rank value of 3, a third CSI-RS resource may have a rank value of 4, and a fourth CSI-RS resource may have a rank value of 5. If the target rank is 7, then the selected subset of CSI-RS resources may include only the third and fourth CSI-RS resources, which may have an aggregated rank value equal to 9.

[0111] For example, a first CSI-RS resource may have a CQI value of 2, a second CSI-RS resource may have a CQI value of 3, a third CSI-RS resource may have a CQI value of 4, and a fourth CSI-RS resource may have a CQI value of 5. If the target CQI value is 2, then the selected subset of CSI-RS resources may include only the fourth CSI-RS resource, which may have a CQI value equal to 5.

[0112] For example, a first CSI-RS resource may have an RSRP value of 2 dB, a second CSI-RS resource may have an RSRP value of 3 dB, a third CSI-RS resource may have an RSRP value of 4 dB, and a fourth CSI-RS resource may have an RSRP value of 5 dB. If the target RSRP is 2 dB, then the selected subset of CSI-RS resources may include only the fourth CSI-RS resource, which may have an RSRP value equal to 5 dB.

[0113] For Type-B, the WTRU may determine (e.g., select) one or more CSI-RS resources based on one or more of an RSRP threshold and / or an RSRP offset, a rank threshold and / or a rank offset, and / or a CQI threshold and / or a CQI offset associated with a CSI-RS resource in the CSI-RS resource set.

[0114] For example, the WTRU may determine RSRP, rank, and / or CQI of a CSI-RS resource and may select the CSI-RS resource if the determined RSRP of the CSI-RS resource, the determined rank of the CSI-RS resource, and / or the determined CQI of the CSI-RS resource is greater than or equal to aconfigured, indicated, and / or fixed RSRP threshold for the CSI-RS resource, a rank threshold for the CSI- RS resource, and / or a CQI threshold for the CSI-RS resource minus a configured, indicated, and / or fixed RSRP offset value for the CSI-RS resource, a rank offset value for the CSI-RS resource, and / or a CQI offset value for the CSI-RS resource.

[0115] For Type-C, the WTRU may determine (e.g., select) one or more CSI-RS resources for CSI determination based on the allocated uplink resources for CSI reporting.

[0116] For example, the WTRU may select one or more CSI-RS resources for CSI determination that results in a maximum aggregated rank (e.g., the rank summed across all the selected CSI-RS resources), a maximum aggregated CQI (e.g., the CQI summed across all the selected CSI-RS resources), and / or a maximum aggregated rank and a maximum aggregated CQI under the constraint that the resulting CSI payload may fit into the allocated uplink resources for CSI reporting.

[0117] A WTRU may determine CSI for the selected subset of CSI-RS resources. In one embodiment, the WTRU may determine a Class-A CSI and / or a Class-B CSI for the determined (e.g., selected) CSI-RS resources.

[0118] For Class-A CSI, the WTRU may determine a respective CSI for each of the determined (e.g., selected) CSI-RS resources. For example, the WTRU may determine a first CSI for a first selected CSI-RS resource and a second CSI for a second selected CSI-RS resource. For example, the WTRU may determine a respective rank value, a respective PM I, and / or a respective CQI value for each of the selected CSI-RS resources.

[0119] For Class-B CSI, the WTRU may determine a single CSI for all the determined (e.g., selected) CSI-RS resources. For example, the WTRU may determine a single CSI for a first and a second selected CSI-RS resource. For example, the WTRU may determine a rank value, a PMI, and / or a CQI value for all selected CSI-RS resources.

[0120] A WTRU may apply one or more CSI inclusion or omission rules. The WTRU may assign a priority value to the determined Class-A CSI and may use the assigned priority value to determine whether to include the Class-A CSI in the CSI report. The priority values may be assigned based on one or more of the following criteria.

[0121] The priority value assigned to a CSI associated with a CSI-RS resource may be based on the RSRP of the CRI. A CSI associated with a CSI-RS resource having the highest RSRP may have the highest priority, while a CSI associated with a CSI-RS resource having the smallest RSRP may have the smallest priority. The priority value assigned to a CSI associated with a CSI-RS resource may also be based on the CQI of the associated CSI-RS resource. A CSI associated with a CSI-RS resource having the highest CQI may have the highest priority, while a CSI associated with a CSI-RS resource having the smallest CQI may have the smallest priority.

[0122] The priority value assigned to a CSI associated with a CSI-RS resource may be based on rank, RSRP and rank, RSRP and CQI, rank and CQI, or RSRP, rank, and CQI of the CSI-RS resource. A CSI associated with a CSI-RS resource having the highest rank may have the highest priority, while a CSI associated with a CSI-RS resource having the smallest rank may have the smallest priority. A CSI associated with a CSI-RS resource having the highest rank and CQI may have the highest priority, while a CSI associated with a CSI-RS resource having the smallest rank and CQI may have the smallest priority.

[0123] For Class-B CSI, the WTRU may assign a priority value to each CSI-RS resource based on RSRP, rank, CQI, RSRP and rank, RSRP and CQI, rank and CQI, or RSRP, rank, and CQI, and may redetermine the Class-B CSI on a subset of the high-priority CSI-RS resources with a resulting Class-B CSI payload size that may fit in the uplink resources. When the uplink resources for Class-B CSI reporting are not sufficient, the WTRU may assign a high priority to the CSI-RS resources with the highest RSRP and a low priority to the CSI-RS resources with the smallest RSRP, and may re-determine the Class-B CSI on a subset of the high-priority CSI-RS resources such that the resulting Class-B CSI payload size may fit in the uplink resources.

[0124] A WTRU may implement one or more CSI reporting priorities. The WTRU may assign a priority value to the Class-A and / or Class-B CSI report to prioritize or de-prioritize it over another CSI report. The priority value assigned to the CSI report may be based on one or more of the following criteria.

[0125] The priority value assigned to the CSI report may be based on the number of CSI-RS resources in the CSI resource set. A CSI-RS resource selection-based CSI report determined based on a larger number of total CSI-RS resources may be prioritized over a CSI-RS resource selection-based CSI report determined based on a smaller number of total CSI-RS resources. A CSI-RS resource selection-based CSI report determined based on a larger number of selected CRIs may be prioritized over a CSI-RS resource selection-based CSI report determined based on a smaller number of selected CSI-RS resources.

[0126] The priority value assigned to the CSI report may also be based on the report type. An aperiodic CSI-RS resource selection-based CSI report may be prioritized over a semi-persistent and / or periodic CSI- RS resource sei ection -based CSI report. A semi-persistent CSI-RS resource selection-based CSI report may be prioritized over a periodic CSI-RS resource selection-based CSI report. An aperiodic single CSI-RS resource selection-based CSI report may be prioritized over a periodic CSI-RS resource selection-based CSI report.

[0127] A WTRU may report CSI (e.g., to a base station). A WTRU may send a CSI report including an indication indicating the selected CSI-RS resource(s). The CSI report may include a Class-A CSI and / or a Class-B CSI.

[0128] For Class-A CSI (e.g., a respective CSI for each of the selected CSI-RS resources in the CSI-RS resource set), the Class-A CSI may include one or more of an indication of the rank value for each of theselected CSI-RS resource(s), an indication of the CQI value for each of the selected CSI-RS resource(s), an indication of the precoding matrix indicator (PM I) for each of the selected CSI-RS resource(s), and / or an indication of the RSRP value for each of the selected CSI-RS resource(s).

[0129] For Class-B CSI (e.g., a CSI for all selected CSI-RS resources in the CSI-RS resource set and / or a CSI for all selected CSI-RS resource indicators (CRIs)), the Class-B CSI may include one or more of an indication of a single aggregated rank value for all the selected CSI-RS resource(s), an indication of a single aggregated CQI value for all the selected CSI-RS resource(s), an indication of a single aggregated PMI (e.g., a single PMI for all the ports in the selected CSI-RS resources) for all the selected CSI-RS resource(s), and / or an indication of a single aggregated RSRP value for all the selected CSI-RS resource(s).

[0130] A WTRU may perform any combination of methods and / or procedures for performing CSI reporting and / or CSI-RS resources selection. A WTRU may receive a semi-static or dynamic CSI-RS configuration for reporting CSI. The CSI-RS configuration may be received via radio resource control (RRC) signaling, medium access control - control element (MAC-CE), and / or downlink control information (DCI). The CSI reference resource may include an indication of the number of CSI-RS resources in a CSI-RS resource set and may also include a number of CSI-RS resource sets. The CSI-RS configuration may further include a CSI-RS resource selection method or CSI-RS resource selection criteria, such as Type-A, Type-B, and / or Type-C Differences between Type-A, Type-B, and Type-C CSI-RS resource selection may be discussed herein. The CSI-RS configuration may further include one or more indications for Class-A and / or Class-B CSI. Class-A and / or Class-B CSI may be determined based on the selected CSI-RS resources in the CSI-RS resource set, and differences between Class-A and Class-B CSI may be discussed herein. In some cases, the WTRU may also be dynamically configured for Class-A and / or Class- B CSI via MAC-CE and / or DCI.

[0131] After reception of the CSI-RS configuration, the WTRU may receive CSI-RS resources for determination of Class-A and / or Class-B CSI. The WTRU may first select a subset of the received CSI-RS resources in the CSI-RS resource set and may then determine Class-A and / or Class-B CSI based on the selected subset of CSI-RS resources. The selected subset of CSI-RS resources may include one or more CSI-RS resources from the CSI-RS resource set.

[0132] A WTRU may select CSI-RS resources. The Type-A, Type-B, and Type-C CSI-RS resource selection methods may be explained with examples.

[0133] When Type-A CSI-RS resource selection is configured, the WTRU may receive a target performance metric. The WTRU may receive a target reference signal received power (RSRP), a target rank, a target channel quality indicator (CQI), a target RSRP and a target rank, a target RSRP and a target CQI, a target rank and a target CQI, or a target RSRP, a target rank, and a target CQI. The WTRU mayreceive a target RSRP equal to 5dB. The WTRU may receive a target rank equal to 7. The WTRU may receive a target CQI equal to the CQI index 10 (e.g,, index 10 in Table 5.2.2.1-2 of 3GPP TS 38.214 Release 17 (e.g., v17.8.0)). The WTRU may receive a target RSRP equal to 5dB and a target rank equal to 7.

[0134] The WTRU may receive one or more CSI-RS resources in the configured CSI-RS resource set. The WTRU may determine a performance-defining metric (e.g., RSRP, rank, and / or CQI) for one or more CSI-RS resources in the CSI-RS resource set. The WTRU may determine or select a subset of the CSI-RS resources in the CSI-RS resource set based on a configured, indicated, and / or fixed target performance metric (e.g., target rank) and based on an aggregated performance-defining metric across one or more CSI-RS resources (e.g., aggregated rank across one or more CSI-RS resources) in the CSI-RS resource set.

[0135] A WTRU may be configured for a target reference signal received power (RSRP) equal to 5dB. The CSI-RS resource set may include four CSI-RS resources. The WTRU may measure the RSRP of each CSI-RS resource. For example, the first, second, third, and / or fourth CSI-RS resources in the CSI-RS resource set may have RSRP values equal to OdB, 1 dB, 2dB, and 3dB, respectively. The aggregated RSRP across the first and second CSI-RS resources in the CSI-RS resource set may be 3.5dB. The aggregated RSRP across the second and third CSI-RS resources in the CSI-RS resource set may be 4.5dB The aggregated RSRP across the third and fourth CSI-RS resources in the CSI-RS resource set may be 6.8dB. The aggregated RSRP across the first, second, and third CSI-RS resources in the CSI-RS resource set may be 5.8dB. The aggregated RSRP across the second, third, and fourth CSI-RS resources in the CSI-RS resource set may be 6.8dB. The aggregated RSRP across the first, second, third, and fourth CSI-RS resources in the CSI-RS resource set may be 7 ,6dB.

[0136] All the subsets, including the subset of the third and fourth CSI-RS resources, the subset of the first, second, and third CSI-RS resources, the subset of the second, third, and fourth CSI-RS resources, and the subset of the first, second, third, and fourth CSI-RS resources, may achieve the target RSRP value of 5dB. The WTRU may determine the minimum number of CSI-RS resources in the CSI-RS resource set that results in the maximum aggregated RSRP value greater than or equal to the target RSRP. The determined or selected subset of CSI-RS resources in the CSI-RS resource set in this example may be the subset including the third and fourth CSI-RS resources in the CSI-RS resource set.

[0137] A WTRU may be configured for a target rank value equal to 10. The CSI-RS resource set may include four CSI-RS resources. The WTRU may measure the rank of each CSI-RS resource. For example, the first, second, third, and / or fourth CSI-RS resources in the CSI-RS resource set may have rank values equal to 2, 3, 5, and 6, respectively. The aggregated rank across the first and second CSI-RS resources in the CSI-RS resource set may be 5. The aggregated rank across the second and third CSI-RS resources inthe CSI-RS resource set may be 7. The aggregated rank across the third and fourth CSI-RS resources in the CSI-RS resource set may be 11 . The aggregated rank across the first, second, and third CSI-RS resources in the CSI-RS resource set may be 10. The aggregated rank across the second, third, and fourth CSI-RS resources in the CSI-RS resource set may be 14. The aggregated rank across the first, second, third, and fourth CSI-RS resources in the CSI-RS resource set may be 16.

[0138] All the subsets, including the subset of the third and fourth CSI-RS resources, the subset of the first, second, and third CSI-RS resources, the subset of the second, third, and fourth CSI-RS resources, and the subset of the first, second, third, and fourth CSI-RS resources, may achieve the target rank value (e.g., 10). The WTRU may determine the minimum number of CSI-RS resources in the CSI-RS resource set that results in the maximum aggregated rank value greater than or equal to the target rank value. The determined or selected subset of CSI-RS resources in the CSI-RS resource set in this example may be the subset including the third and fourth CSI-RS resources in the CSI-RS resource set.

[0139] A WTRU may be configured for a target channel quality indicator (CQI) value (e.g., 6). The CSI- RS resource set may include four CSI-RS resources. The WTRU may measure the CQI of each CSI-RS resource. For example, the first, second, third, and fourth CSI-RS resources in the CSI-RS resource set may have CQI values equal to 1, 2, 3, and 4, respectively. The aggregated CQI across the first and second CSI-RS resources in the CSI-RS resource set may be 3. The aggregated CQI across the second and thirdCSI-RS resources in the CSI-RS resource set may be 5. The aggregated CQI across the third and fourthCSI-RS resources in the CSI-RS resource set may be 7. The aggregated CQI across the first, second, and third CSI-RS resources in the CSI-RS resource set may be 6. The aggregated CQI across the second, third, and fourth CSI-RS resources in the CSI-RS resource set may be 9. The aggregated CQI across the first, second, third, and fourth CSI-RS resources in the CSI-RS resource set may be 10.

[0140] All the above-mentioned subsets, except for the subset including the first and second CSI-RS resources and the subset including the second and third CSI-RS resources, may achieve the target CQI value (e.g., 6). The WTRU may determine the minimum number of CSI-RS resources in the CSI-RS resource set that results in the maximum aggregated CQI value greater than or equal to the target CQI value. The determined or selected subset of CSI-RS resources in the CSI-RS resource set in this example may be the subset including the third and fourth CSI-RS resources in the CSI-RS resource set.

[0141] A WTRU may semi-statically or dynamically (e.g., by radio resource control (RRC), medium access control - control element (MAC-CE), and / or downlink control information (DCI)) receive a maximum and / or a minimum number indicating the maximum and / or minimum number of CSI-RS resources in a subset of CSI-RS resources to be determined (e.g., selected) from the CSI-RS resource set based on the configured target performance-defining metric (e.g., target rank and / or target CQI). The WTRU may determine a subset of CSI-RS resources, where the number of CSI-RS resources in the subset does notexceed the configured maximum number of CSI-RS resources in the subset. The WTRU may determine a subset of CSI-RS resources, where the number of CSI-RS resources is equal to or greater than the configured minimum number of CSI-RS resources in the subset.

[0142] A WTRU may adjust the configured, indicated, or fixed maximum and / or minimum number of CSI- RS resources in a subset of CSI-RS resources based on one or more factors. The WTRU may reduce the maximum number of CSI-RS resources when a smaller number of CSI-RS resources may achieve the target performance-defining metric (e.g., target rank). The WTRU may send an indication in a CSI report to indicate the maximum number of CSI-RS resources needed in a subset to achieve the target performancedefining metric (e.g., target rank).

[0143] The WTRU may further reduce the minimum number of CSI-RS resources when the available uplink resources for CSI reporting are not sufficient to report a CSI. The WTRU may send an indication in a CSI report to indicate the minimum number of CSI-RS resources needed in a subset to achieve the target performance-defining metric (e.g., target rank).

[0144] The WTRU may send an indication to reduce the target performance-defining metric (e.g., target rank) if the configured number of CSI-RS resources in the set and / or if the maximum number of allowed CSI-RS resources in a subset of CSI-RS resources is not sufficient to achieve the target rank performance. The WTRU may send an indication in the CSI report to indicate that the target rank cannot be achieved. The WTRU may send an indication in the CSI report to indicate the maximum rank that can be achieved using the configured maximum and the minimum number of allowed CSI-RS resources in the CSI-RS resource set.

[0145] When two or more subsets of CSI-RS resources may satisfy the configured target performancedefining metric (e.g., target rank), the subset index may be selected based on one or more of the following. The subset may be selected based on the smallest or highest index. The subset may be selected based on the CSI-RS resources achieving the maximum performance-defining metric (e.g., the subset with the highest rank, CQI, and / or RSRP values). The subset may be selected based on the smallest number of CSI-RS resources. The subset may be selected based on a number of CSI-RS resources that can fully fit into the available uplink resources for CSI reporting. The subset may be selected based on including CSI- RS resources with the smallest or largest indices.

[0146] When Type-B CSI-RS resource selection is configured, the WTRU may be semi-statically or dynamically (e.g., by RRC, MAC-CE, and / or DCI) configured for a performance-defining threshold (e.g., rank threshold) for one or more CSI-RS resources in the CSI-RS resource set.

[0147] The WTRU may receive an RSRP threshold, a rank threshold, a CQI threshold, an RSRP threshold and a rank threshold, an RSRP threshold and a CQI threshold, a rank threshold and a CQI threshold, or an RSRP threshold, a rank threshold, and a CQI threshold. The WTRU may receive an RSRPthreshold equal to 5dB. The WTRU may receive a rank threshold equal to 7. The WTRU may receive a CQI threshold equal to the CQI index 10 (e.g., index 10 in Table 5.2.2.1-2 of 3GPP TS 38.214 Release 17 (e.g., V17.8.0)). The WTRU may receive an RSRP threshold equal to 5dB and a target threshold equal to 7.

[0148] The WTRU may receive a performance-defining threshold (e.g., rank threshold) applicable to one or more CSI-RS resources in a CSI-RS resource set. The WTRU may determine whether to include or not to include (e.g., whether to select or not to select) a CSI-RS resource in a subset of CSI-RS resources based on the performance-defining threshold (e.g., rank threshold).

[0149] When the rank of a CSI-RS resource is greater than or equal to the configured, indicated, or fixed rank threshold associated with the CSI-RS resource, the WTRU may include the CSI-RS resource in the subset of CSI-RS resources. When the CQI of a CSI-RS resource is greater than or equal to the configured, indicated, or fixed CQI threshold associated with the CSI-RS resource, the WTRU may include the CSI-RS resource in the subset of CSI-RS resources. When the RSRP of a CSI-RS resource is greater than or equal to the configured, indicated, or fixed RSRP threshold associated with the CSI-RS resource, the WTRU may include the CSI-RS resource in the subset of CSI-RS resources.

[0150] The WTRU may be semi-statically or dynamically (e.g., by RRC, MAC-CE, and / or DCI) configured for a performance-defining (e.g., rank, CQI, and / or RSRP) offset value associated with one or more CSI-RS resources in the CSI-RS resource set. The WTRU may also be semi-statically or dynamically (e.g , by RRC, MAC-CE, and / or DCI) configured for a performance-defining threshold (e.g., rank, CQI, and / or RSRP). The WTRU may determine whether to include or not to include (e.g., whether to select or not to select) CSI-RS resources in a subset of CSI-RS resources based on the performance-defining (e.g., rank) threshold value and based on the performance-defining (e.g., rank) offset value.

[0151] The rank threshold value and rank offset value associated with a CSI-RS resource in the CSI-RS resource set may be 4 and 1 , respectively. The WTRU may include a CSI-RS resource in the subset of CSI-RS resources when its measured, determined, or actual rank value is greater than or equal to the configured rank threshold minus the configured rank offset (e.g., a CSI-RS resource with a measured, determined, or actual rank value greater than or equal to 3 may be included in the subset of CSI-RS resources).

[0152] The CQI threshold value and CQI offset value associated with a CSI-RS resource in the CSI-RS resource set may be 4 and 1 , respectively. The WTRU may include a CSI-RS resource in the subset of CSI-RS resources when its measured, determined, or actual CQI value is greater than or equal to the configured CQI threshold minus the configured CQI offset (e.g., a CSI-RS resource with a measured, determined, or actual CQI value greater than or equal to 3 may be included in the subset of CSI-RS resources).

[0153] The RSRP threshold value and RSRP offset value associated with a CSI-RS resource in the CSI- RS resource set may be 4dB and 2dB, respectively. The WTRU may include a CSI-RS resource in the subset of CSI-RS resources when its measured, determined, or actual RSRP value is greater than or equal to the configured RSRP threshold minus the configured RSRP offset (e.g., a CSI-RS resource with a measured, determined, or actual RSRP value greater than or equal to -0.3dB may be included in the subset of CSI-RS resources).

[0154] The WTRU may be semi-statically or dynamically (e.g., by RRC, MAC-CE, and / or DCI) configured for a maximum and / or a minimum number of CSI-RS resources to be included in the subset of CSI-RS resources. Additionally, and / or alternatively, the WTRU may be semi-statically or dynamically (e.g., by RRC, MAC-CE, and / or DCI) configured for a fixed number of CSI-RS resources in the CSI-RS resource set. The number of CSI-RS resources in the CSI-RS resource set may be four, and the subset of CSI-RS resources may have a maximum of three and a minimum of two CSI-RS resources. The subset of CSI-RS resources may have a fixed number of CSI-RS resources equal to two. The CSI-RS resource selection for determination of the subset of CSI-RS resources may be based on the maximum number of CSI-RS resources that may be included in the subset of CSI-RS resources, the minimum number of CSI-RS resources that may be included in the subset of CSI-RS resources, a fixed number of CSI-RS resources in the subset of CSI-RS resources, the configured, indicated, or fixed performance-defining (e.g., rank, CQI, and / or RSRP) threshold, and / or the configured, indicated, or fixed performance-defining (e.g., rank, CQI, and / or RSRP) offset values.

[0155] The CSI-RS resource set may include four CSI-RS resources. The maximum and minimum number of CSI-RS resources that may be included in the subset of CSI-RS resources may be three and two CSI-RS resources, respectively. The rank threshold and the rank offset values may be four and one, respectively. The rank threshold and the rank offset may be associated with all CSI-RS resources. The WTRU may determine the rank of each CSI-RS resource, which may be equal to 1 , 2, 5, and 7 for the first, second, third, and fourth CSI-RS resources in the CSI-RS resource set, respectively. Based on the rank threshold and the rank offset, the subset of CSI-RS resources may include the third and the fourth CSI-RS resources.

[0156] The CSI-RS resource set may include four CSI-RS resources. The subset of CSI-RS resources may have a fixed number of CSI-RS resources equal to two. The rank threshold and the rank offset values may be four and one, respectively. The rank threshold and the rank offset may be associated with all CSI- RS resources. The WTRU may determine the rank of each CSI-RS resource, which may be equal to 1 , 2, 0, and 3 for the first, second, third, and fourth CSI-RS resources in the CSI-RS resource set, respectively. Based on the rank threshold and the rank offset, the subset of CSI-RS resources may include the second and the fourth CSI-RS resources.

[0157] When the performance-defining offset value is equal to zero or is absent, the subset of CSI-RS resource selection may be based on the performance-defining threshold value.

[0158] The WTRU may be semi-statically or dynamically (e.g., by RRC, MAC-CE, and / or DOI) configured for a minimum performance-defining (e.g., rank, CQI, and / or RSRP) threshold. A CSI-RS resource to be included in the subset of CSI-RS resources may be required to have a minimum rank of four. The minimum performance-defining threshold may be configured for one or more CSI-RS resources in the CSI-RS resource set, and / or one or more CSI-RS resource sets may have the same minimum performance-defining threshold. The WTRU may be semi-statically or dynamically (e.g., by RRC, MAC-CE, and / or DCI) configured for a performance-defining offset value (e.g., rank, CQI, and / or RSRP offset value). The CSI-RS resource selection for determination of the subset of CSI-RS resources may be based on the minimum performance-defining threshold value and the performance-defining offset value.

[0159] The CSI-RS resource set may include four CSI-RS resources. The minimum rank threshold for each CSI-RS resource in the CSI-RS resource set may be four. The rank offset value for the first, second, third, and fourth CSI-RS resources in the CSI-RS resource set may be 1 , 2, 2, and 3, respectively. The WTRU may determine the rank of each CSI-RS resource, which may be equal to 5, 2, 5, and 8 for the first, second, third, and fourth CSI-RS resources in the CSI-RS resource set, respectively. Based on the minimum rank threshold and the rank offset values, the effective ranks of the CSI-RS resources in the CSI- RS resource set may be 4, 0, 3, and 5, respectively. Based on the effective ranks, the subset of CSI-RS resources may include the first and the fourth CSI-RS resources in the CSI-RS resource set.

[0160] When Type-C CSI-RS resources selection is configured, the WTRU may be further semi-statically or dynamically (e.g., by RRC, MAC-CE, and / or DCI) configured for time and / or frequency-domain uplink resources dedicated for CSI reporting. The WTRU may determine a subset of CSI-RS resources for CSI determination based on the allocated uplink time and / or frequency-domain resources for CSI reporting.

[0161] The WTRU may be allocated time and / or frequency-domain uplink resources for CSI reporting. The resources may be sufficient only to report a CSI associated with a single CSI-RS resource in the CSI- RS resource set. Different CSI-RS resources may have different rank values, which may result in different payload sizes. The WTRU may select one or more CSI-RS resources with a payload size that can fit into the allocated uplink resources for CSI reporting.

[0162] The CSI-RS resource set may include four CSI-RS resources, each associated with different payload sizes. The payload sizes associated with the first, second, third, and / or fourth CSI-RS resources may fit into the allocated uplink resources for CSI reporting. The WTRU may select the CSI-RS resource with the maximum rank, the maximum CQI, the maximum RSRP, and / or the maximum payload size for CSI reporting.

[0163] The third CSI-RS resource may have the highest rank, the highest CQI, the highest RSRP, and / or the highest payload size. The WTRU may select the third CSI-RS resource for CSI reporting.

[0164] Each CSI report may include high-priority CSI content (e.g., the CSI contents in group 1 of a CSI report) and low-priority CSI content (e.g., the CSI contents in group 2 of a CSI report). The CSIs associated with two CSI-RS resources may fit into the allocated uplink time and / or frequency-domain uplink resources for CSI reporting (e.g., all CSI contents of the first and second CSI-RS resources may fit into the allocated uplink resources). The high-priority CSI contents associated with all CSI-RS resources in the CSI-RS resource set (e.g., high-priority CSI contents of all CSI-RS resources) may fit into the allocated uplink resources for CSI reporting. The WTRU may select all the high-priority CSI contents associated with all the CSI-RS resources for reporting.

[0165] The WTRU may determine a subset of CSI-RS resources from the CSI-RS resource set using the Type-A, Type-B, or Type-C subset selection methods. Based on the subset of CSI-RS resources, the WTRU may determine a CSI. The WTRU may determine a Class-A CSI report or a Class-B CSI report.

[0166] The WTRU may determine a CSI for each of the CSI-RS resources in the determined (e.g., selected) subset of CSI-RS resources, for instance, for a Class A CSI report. For example, the WTRU may determine a CSI (e.g., a CQI, a PMI, and / or a rank) for each CSI-RS resource in the CSI-RS resource set.

[0167] The CSI-RS resource set may include four CSI-RS resources, and the selected subset of CSI-RS resources may include two CSI-RS resources (e.g., the first CSI-RS resource and the second CSI-RS resource). The WTRU may determine a first CSI (e.g., a first CQI, a first PMI, and / or a first rank) based on the first CSI-RS resource and a second CSI (e.g., a second CQI, a second PMI, and / or a second rank) based on the second CSI-RS resource.

[0168] Each CSI-RS resource in the CSI-RS resource set may have the same or a different number of CSI-RS antenna ports. All CSI-RS resources may have the same number of CSI-RS antenna ports. The first and second CSI-RS resources may have an equal number of antenna ports (e.g., the number of antenna ports in the first CSI-RS resource may be N_1 , and the number of antenna ports in the second CSI-RS resource may also be N_1). The third and fourth CSI-RS resources may have an equal number of antenna ports (e.g., the number of antenna ports in the third CSI-RS resource may be N_2, and the number of antenna ports in the fourth CSI-RS resource may also be N_2). The number of antenna ports in the first CSI-RS resource may be different from the number of antenna ports in the fourth CSI-RS resource (e.g., N_1 may not be equal to N_2).

[0169] The WTRU may use the same codebook for CSI determination (e.g., for PMI determination) on CSI-RS resources with the same number of CSI-RS antenna ports. The first and second CSI-RS resources may have an equal number of antenna ports (e.g., the number of antenna ports in the first CSI-RS resource may be N_1 , and the number of antenna ports in the second CSI-RS resource may also be N_1 ). The thirdand fourth CSI-RS resources may have an equal number of antenna ports (e.g . , the number of antenna ports in the third CSI-RS resource may be N_2 , and the number of antenna ports in the fourth CSI-RS resource may also be N_2), The number of antenna ports in the first CSI-RS resource may be different from the number of antenna ports in the fourth CSI-RS resource (e.g., N_1 may not be equal to N_2). The WTRU may use a first codebook for a first and second CSI determination based on the first and second CSI-RS resources and a second codebook for a third and fourth CSI determination based on the third and fourth CSI-RS resources.

[0170] The WTRU may determine a single CSI (e.g., a single PM I, a single CQI value, and / or a single rank value) based on all the CSI-RS resources in the CSI-RS resource set and / or based on all the CSI-RS resources in the determined (e.g., selected) subset of CSI-RS resources, for instance, for a Class B CSI report. For example, the CSI-RS resource set may include four CSI-RS resources. Each CSI-RS resource may have thirty-two CSI-RS antenna ports. All the CSI-RS resources may have a total of one hundred and twenty-eight CSI-RS antenna ports (e.g., the first CSI-RS resource may have CSI-RS antenna ports one to thirty-two, the second CSI-RS resource may have CSI-RS antenna ports thirty-three to sixty-four, and so on). The WTRU may determine a single PMI with a PMI dimension equal to one hundred and twenty-eight antenna ports from a single codebook with a codebook dimension proportional to one hundred and twentyeight antenna ports.

[0171] The CSI-RS resource set may include four CSI-RS resources. Each CSI-RS resource may have thirty-two CSI-RS antenna ports. All the CSI-RS resources may have a total of one hundred and twentyeight CSI-RS antenna ports (e.g., the first CSI-RS resource may have CSI-RS antenna ports one to thirty- two, the second CSI-RS resource may have CSI-RS antenna ports thirty-three to sixty-four, and so on). The selected subset of CSI-RS resources may include two CSI-RS resources (e.g., the first CSI-RS resource and the third CSI-RS resource of the CSI-RS resource set). The subset of CSI-RS resources may have sixty-four antenna ports (e.g., the thirty-two CSI-RS antenna ports associated with the first CSI-RS resource of the CSI-RS resource set and the thirty-two CSI-RS antenna ports associated with the third CSI- RS resource of the CSI-RS resource set). The WTRU may determine a single PMI with a PMI dimension equal to sixty-four from a single codebook with a codebook dimension proportional to sixty-four CSI-RS antenna ports.

[0172] The WTRU and / or the network may support CSI omission and CSI inclusion rules to establish a common understanding between the network (e.g., gNB or base station) and the WTRU regarding the reported CSI contents, particularly in cases where the uplink time and / or frequency-domain resources for CSI reporting are insufficient, and the WTRU may need to drop or prioritize certain CSI elements (e.g., CQI, rank, co-phasing coefficients) to comply with the network on the allocated uplink resources for CSI reporting.

[0173] The WTRU may determine a CSI, and the CSI payload size may be larger than the uplink resources allocated by the network for CSI reporting. The WTRU may be required to drop certain CSI elements and prioritize others for reporting. The WTRU and / or the network may facilitate dropping and prioritizing through CSI omission rules. Furthermore, two types of CSI, broadly classified as Type-I and Type-ll CSI may be supported. The existing CSI omission rules may be designed and specified only for Type-ll CSI, as it may result in a larger CSI payload size, thereby necessitating rules to manage the payload size of Type-ll CSI.

[0174] An increase in the number of CSI-RS ports may lead to an increase in the resulting rank of the channel matrix, an increase in the PM I dimension, and an increase in the CSI payload size. Therefore, for a larger number of antenna ports, the need for CSI omission and CSI inclusion may increase, even for Type-I CSI, particularly for Class-A CSI, where one CSI may be determined per CSI-RS resource.

[0175] The WTRU may be configured with CSI reporting prioritization for Class-A CSI.

[0176] For example, Class-A CSI may be reported in a plurality of ways. Each CSI determined for a CSI- RS reference resource may be reported in a separate CSI report and / or all CSI associated with all CSI-RS resources in the resource set and / or all CSI-RS resources in the determined subset of CSI-RS resources may be reported in a single CSI report.

[0177] The CSI-RS resource set may include four CSI-RS resources. The WTRU may determine a CSI for each CSI-RS resource and report all the CSIs in a single CSI report. The CSI-RS resource set may include four CSI-RS resources, and the WTRU may determine a CSI for each CSI-RS resource and report each CSI in four different CSI reports.

[0178] The CSI-RS resource set may include four CSI-RS resources, and the selected subset of CSI-RS resources may include two CSI-RS resources. The WTRU may determine a CSI for each of the two CSI- RS resources in the selected subset of CSI-RS resources and report the two CSIs in a single CSI report. The CSI-RS resource set may include four CSI-RS resources, and the selected subset of CSI-RS resources may include two CSI-RS resources. The WTRU may determine a CSI for each of the two CSI- RS resources in the selected subset of CSI-RS resources and report the two CSIs in two different CSI reports.

[0179] A first CSI, a second CSI, a third CSI, and a fourth CSI may be associated with a first CSI-RS resource, a second CSI-RS resource, a third CSI-RS resource, and a fourth CSI-RS resource, respectively. The first, second, third, and fourth CSIs may be reported in a single CSI report and / or the first, second, third, and fourth CSIs may be reported in four different CSI reports.

[0180] Within a single CSI report and / or across two or more CSI reports associated with the CSI-RS resources in the CSI-RS resource set and / or the selected subset of CSI-RS resources, the CSIs may be prioritized for reporting based on one or more of the following criteria.

[0181] The WTRU may prioritize and / or de-prioritize the CSI associated with a CSI-RS resource based on the strength of the RSRP value of the corresponding CSI-RS resource.

[0182] The CSI-RS resource set may include four CSI-RS resources. The first, second, third, and fourth CSI-RS resources in the CSI-RS resource set may have RSRP values equal to 4dB, 2dB, OdB, and 5dB, respectively. The first, second, third, and fourth CSI-RS resources may be associated with the first, second, third, and fourth CSIs, respectively. The WTRU may assign the highest priority to the fourth CSI, the second highest priority to the first CSI, the third highest priority to the second CSI, and the fourth highest priority to the third CSI.

[0183] When the uplink resources for CSI reporting may be limited and may only fit one CSI, the WTRU may report only the fourth CSI. When the uplink resources for CSI reporting may be limited and may only fit two CSIs, the WTRU may report only the fourth and first CSIs.

[0184] The WTRU may prioritize and / or de-prioritize the CSI associated with a CSI-RS resource based on the rank value of the corresponding CSI-RS resource.

[0185] The CSI-RS resource set may include four CSI-RS resources. The first, second, third, and fourth CSI-RS resources in the CSI-RS resource set may have rank values equal to 4, 2, 0, and 5, respectively. The first, second, third, and fourth CSI-RS resources may be associated with the first, second, third, and fourth CSIs, respectively. The WTRU may assign the highest priority to the fourth CSI, the second highest priority to the first CSI, the third highest priority to the second CSI, and the fourth highest priority to the third CSI.

[0186] When the uplink resources for CSI reporting may be limited and may only fit one CSI, the WTRU may report only the fourth CSI. When the uplink resources for CSI reporting may be limited and may only fit two CSIs, the WTRU may report only the fourth and first CSIs.

[0187] In an example, the WTRU may prioritize and / or de-prioritize the CSI associated with a CSI-RS resource based on the CQI value of the corresponding CSI-RS resource. The CSI-RS resource set may include four CSI-RS resources. The first, second, third, and fourth CSI-RS resources in the CSI-RS resource set may have CQI values (e.g., CQI indices as in Table 5.2.2.1-2 of TS 38.214 v17.8.0) equal to 4, 2, 0, and 5, respectively. The first, second, third, and fourth CSI-RS resources may be associated with the first, second, third, and fourth CSIs, respectively. The WTRU may assign the highest priority to the fourth CSI, the second highest priority to the first CSI, the third highest priority to the second CSI, and the fourth highest priority to the third CSI.

[0188] When the uplink resources for CSI reporting may be limited and may only fit one CSI, the WTRU may report only the fourth CSI. When the uplink resources for CSI reporting may be limited and may only fit two CSIs, the WTRU may report only the fourth and first CSIs. The WTRU may prioritize and / or de- prioritize the CSI associated with a CSI-RS resource based on the CQI value, the rank value, and / or theRSRP value of the CSI-RS resource. The different CSI contents of the prioritized CSI may further be prioritized and / or de-prioritized based on the CSI omission rules (e.g., 5G NR CSI omission rules).

[0189] Based on RSRP, the WTRU may prioritize the CSI of a first CSI-RS resource over the CSI of a second CSI-RS resource. Different CSI contents (e.g., rank, PMI, and / or CQI) of the CSI associated with the first CSI-RS resource may be prioritized over each other, where the priorities to the different contents of the CSI may be assigned based on the CSI omission rules (e.g., those defined in TS 38.214 Release 17). The WTRU may prioritize reporting the rank values of the high-priority CSI-RS resource over the PMI values of the high-priority CSI-RS resource. The WTRU may prioritize reporting the wideband CQI value of the high-priority CSI-RS resource over the sub-band CQI values of the high-priority CSI-RS resource. The WTRU may prioritize reporting the sub-band CQIs of the high-priority CSI-RS resource over the rank of the low-priority CSI-RS resource.

[0190] The CSI-RS resource domain may have the highest priority, the spatial domain may have the second-highest priority, the frequency domain may have the third-highest priority, and the time domain may have the lowest priority. The WTRU may prioritize and / or de-prioritize the CSI associated with a CSI-RS resource based on the index of the CSI-RS resource in the CSI-RS resource set. The CSI of a CSI-RS resource with the smallest index may be prioritized over the CSI of a CSI-RS resource with a larger index. The CSI associated with a first CSI-RS resource in the selected subset of CSI-RS resources may be prioritized over the CSI of a second CSI-RS resource in the selected subset of CSI-RS resources.

[0191] In one embodiment, different CSI contents of a CSI associated with one CSI-RS resource (e.g., rank, PMI, and / or CQI of a first CSI-RS resource) may also be prioritized over different CSI contents of a CSI associated with another CSI-RS resource (e.g., rank, PMI, and / or CQI of a second CSI-RS resource) when all the CSIs are placed in a single CSI report and / or the CSIs are placed in different CSI reports. Within one CSI report and / or across two or more CSI reports associated with the CSI-RS resources in the CSI-RS resource set and / or associated with the CSI-RS resources in the selected subset of CSI-RS resources, the CSIs may be divided into different parts, portions, groups, and / or partitions.

[0192] A single CSI report may include all CSI. The CSI report may have two or more parts, groups, portions, and / or partitions. A first portion may contain indices of the CSI-RS resources in the subset of CSI- RS resources, rank values of the CSI-RS resources in the subset of CSI-RS resources, and wideband CQI values equal in number to the number of CSI-RS resources in the subset of CSI-RS resources and associated with the CSI-RS resources in the subset of CSI-RS resources.

[0193] A second portion may contain a wideband single PMI associated with the CSI-RS resources in the subset of CSI-RS resources and / or a number of wideband PMIs equal in number to the number of CSI- RS resources in the subset of CSI-RS resources and associated with the CSI-RS resources in the subsetof CSI-RS resources (e.g . , two PMIs for two CSI-RS resources in the selected subset of CSI-RS resources).

[0194] A third portion may contain subband PMIs associated with the CSI-RS resources in the subset of CSI-RS resources and / or a number of subband PMIs equal in number to the number of CSI-RS resources in the subset of CSI-RS resources and associated with the CSI-RS resources in the subset of CSI-RS resources (e.g., two subband PMIs associated with the CSI-RS resources in the selected subset of CSI-RS resources).

[0195] A fourth portion may contain subband CQIs associated with the CSI-RS resources in the subset of CSI-RS resources and / or a number of subband CQIs equal in number to the number of CSI-RS resources in the subset of CSI-RS resources and associated with the CSI-RS resources in the subset of CSI-RS resources (e.g., two subband CQIs associated with the CSI-RS resources in the selected subset of CSI-RS resources).

[0196] In an example, the WTRU may prioritize the first portion over the second, third, and fourth portions. The WTRU may prioritize the second portion over the third and fourth portions. The WTRU may prioritize the third portion over the fourth portion.

[0197] In one embodiment, the WTRU may prioritize the first part over the second part. The first part may include all rank values, indices of the CSI-RS resources in the selected subset of CSI-RS resources, wideband CQI values, and wideband PMIs. The second part may include the sub-band CQI values and the sub-band PMIs.

[0198] In another embodiment, the CSIs associated with the CSI-RS resources may be prioritized based on a configured, indicated, and / or fixed rule. The CSI associated with the odd-numbered CSI-RS resources in the CSI-RS resource set may be prioritized over the CSI associated with the even-numbered CSI-RS resources in the CSI-RS resource set. The CSI associated with the odd-numbered CSI-RS resources in the selected subset of CSI-RS resources may be prioritized over the CSI associated with the even-numbered CSI-RS resources in the selected subset of CSI-RS resources.

[0199] At a first CSI reporting instant in a series of CSI reporting instances, at odd-numbered CSI reporting instances, the CSI associated with the odd-numbered CSI-RS resources in the CSI-RS resource set may be prioritized over the CSI associated with the even-numbered CSI-RS resources in the CSI-RS resource set. At even-numbered CSI reporting instances, the CSI associated with the even-numbered CSI- RS resources in the CSI-RS resource set may be prioritized over the CSI associated with the odd- numbered CSI-RS resources in the CSI-RS resource set.

[0200] The WTRU may implement CSI reporting priority. The network (e.g., a gNB or base station) may allocate uplink resources for CSI reporting. The network, such as a gNB, may also configure CSI reporting. The network may configure more than one CSI report, and the allocated time and frequency resources forthe CSI reporting may collide and / or overlap in one or more time and / or frequency domain resources. For example, the network may configure two CSI reports in different bandwidth parts, and the uplink resources for reporting of the two CSI reports may collide and / or overlap in one or more time and / or frequency domain resources (e.g. , in one or more OFDM sub-carriers).

[0201] In the event of such an overlap and / or collision of the time and / or frequency domain resources, the WTRU may follow some CSI reporting priority rules to select and report one of the CSI reports and drop the remaining reports. The CSI reporting rules may be designed for CSIs that are determined on a single CSI-RS resource in the CSI-RS resource set and / or when the CSI-RS resource set has only one CSI-RS resource. For CSI determined on more than one CSI-RS resource in the CSI-RS resource set (e.g , Class- A CSI and / or Class-B CSI), as is the subject matter of this discussion, the CSI reporting priority rules may fall short and may require enhancements.

[0202] For a CSI report determined based on multiple CSI-RS resources in a CSI-RS resource set (e.g., Class-A CSI and / or Class-B CSI), the priority value to a CSI report may be assigned based on one or more of the following. The priority value to a CSI report may be assigned based on the number of CSI-RS resources in the CSI-RS resource set. For example, a first CSI report may be determined based on a first CSI-RS resource set that has four CSI-RS resources. A second CSI report may be determined based on a second CSI-RS resource set that has eight CSI-RS resources. The WTRU may assign a higher priority value to the first CSI report and a lower priority value to the second CSI report.

[0203] The priority value to a CSI report may be assigned based on the number of CSI-RS antenna ports in the CSI-RS resource set. For example, a first CSI report may be determined based on a first CSI-RS resource set that has sixty-four CSI-RS antenna ports across the CSI-RS resource set. A second CSI report may be determined based on a second CSI-RS resource set that has one hundred and twenty-eight CSI-RS antenna ports across the CSI-RS resource set. The WTRU may assign a higher priority value to the second CSI report and a lower priority value to the first CSI report.

[0204] The priority value to a CSI report may be assigned based on the number of CSI-RS resources in the selected subset of CSI-RS resources. For example, a first CSI report may be determined based on a first subset of CSI-RS resources that has two CSI-RS resources. A second CSI report may be determined based on a second subset of CSI-RS resources that has three CSI-RS resources. The WTRU may assign a higher priority value to the second CSI report and a lower priority value to the first CSI report.

[0205] The priority value to a CSI report may be assigned based on the number of CSI-RS resources in the CSI-RS resource set and based on the number of CSI-RS resources in the selected subset of CSI-RS resources. The priority value to a CSI report may also be assigned based on the CSI report type (e.g., aperiodic, periodic, and / or semi-persistent CSI report).

[0206] For example, an aperiodic CSI report determined based on a first CSI-RS resource set with a single CSI-RS resource may be prioritized over a periodic and semi-persistent CSI report determined based on a second CSI-RS resource set with more than one CSI-RS resource.

[0207] A semi-persistent CSI report determined based on a first CSI-RS resource set with a single CSI- RS resource may be prioritized over a periodic CSI report determined based on a second CSI-RS resource set with more than one CSI-RS resource. An aperiodic CSI report determined based on a first CSI-RS resource set with more than one CSI-RS resource may be prioritized over a periodic and semi-persistent CSI report determined based on a second CSI-RS resource set with more than one CSI-RS resource. A semi-persistent CSI report determined based on a first CSI-RS resource set with more than one CSI-RS resource may be prioritized over a periodic CSI report determined based on a second CSI-RS resource set with more than one CSI-RS resource.

[0208] The priority value to a CSI report may be assigned based on the codebook type (e.g., the so- called Type-1 codebook and / or the so-called Type-ll codebook used for CSI determination) used for determination of the CSI report. For example, a first CSI determined using a first codebook (e.g., Type-ll codebook) may be prioritized over a second CSI determined using a second codebook (e.g., Type-1 codebook). The priority value to a CSI report may be assigned based on the codebook parameters used for determination of the CSI.

[0209] A first CSI determined using a larger DFT-oversampling value may be prioritized over a second CSI determined using a smaller DFT-oversampling value. A first CSI determined for a larger number of DFT-beams may be prioritized over a second CSI determined for a smaller number of DFT-beams. A first CSI that includes sub-band level CSI information may be prioritized over a second CSI without any subband level CSI information. A first CSI determined using a first codebook mode (e.g., the so-called Type-1 codebook mode-2) may be prioritized over a second CSI determined using a second codebook mode (e.g., the so-called Type-1 codebook mode-2).

[0210] The priority value to a CSI report may be assigned based on the number of antenna panels (e.g., at the network side, at the WTRU side, and / or both at the network and at the WTRU side) used for determination of the CSI report. For example, a first CSI report determined for a larger number of antenna panels may be prioritized over a second CSI report determined for a smaller number of antenna panels. The priority value to a CSI report may be assigned based on the performance-defining metrics (e.g., RSRP, CQI, and / or rank).

[0211] A first CSI report with an RSRP value (e.g., an aggregated RSRP value and / or the RSRP of a single CSI-RS resource) equal to 1 dB may be prioritized over a second CSI report with an RSRP value (e.g., an aggregated RSRP value and / or just the RSRP of a single CSI-RS resource) equal to OdB. A first CSI report with a CQI value (e.g., an aggregated CQI value and / or the CQI of a single CSI-RS resource)equal to 1 may be prioritized over a second CSI report with a CQI value (e.g., an aggregated CQI value and / or the CQI of a single CSI-RS resource) equal to OdB. A first CSI report with a rank value (e.g., an aggregated rank value and / or the rank of a single CSI-RS resource) equal to 4 may be prioritized over a second CSI report with a rank value (e.g., an aggregated rank value and / or the rank of a single CSI-RS resource) equal to 3.

[0212] The priority value to a CSI report may be assigned based on the payload size of the CSI report. For example, a first CSI report with a payload size equal to 100 bits, where 90 bits are related to the actual CSI and the remaining 10 bits are zero-padded bits, may be prioritized over a second CSI report with a payload size equal to 100 bits, where 80 bits are related to the actual CSI report and the remaining 20 bits are zero-padded bits.

[0213] The priority value to a CSI report may be assigned based on the number of subbands. For example, a first CSI report determined for a larger number of subbands may be prioritized over a second CSI report determined for a smaller number of subbands. The priority value to a CSI report may be assigned based on the latency class associated with the CSI report. For example, a first CSI report with a higher latency restriction may be prioritized over a second CSI report with a looser latency restriction.

[0214] For Class-A CSI, a priority value may be assigned to each CSI associated with a CSI-RS resource. For example, a CSI-RS resource set may have four CSI-RS resources. The WTRU may determine four CSIs, where each CSI may be associated with a single CSI-RS resource in the CSI-RS resource set. For example, the CSI-RS resource set may have four CSI-RS resources. The WTRU may determine a subset of CSI-RS resources, where the subset may include two CSI-RS resources. The WTRU may determine two CSIs, where each CSI may be associated with a single CSI-RS resource in the subset of CSI-RS resources.

[0215] For Class-A CSI, the priority values to each CSI may be assigned based on the number of antenna ports in the CSI-RS resource. For example, a first CSI-RS resource in the CSI-RS resource set may have a larger number of antenna ports compared to a second CSI-RS resource in the CSI-RS resource set. As compared to the priority value assigned to the second CSI associated with the second CSI-RS resource in the CSI-RS resource set, the WTRU may assign a higher priority to the CSI associated with the first CSI-RS resource in the CSI-RS resource set.

[0216] For Class-A CSI, the priority values to each CSI may be assigned based on the performancedefining metrics (e.g., CQI, rank, and / or RSRP) of the associated CSI-RS resource in the CSI-RS resource set. A first CSI associated with a first CSI-RS resource in the CSI-RS resource set may have a higher CQI value compared to a second CSI associated with a second CSI-RS resource in the CSI-RS resource set. As compared to the priority value assigned to the second CSI associated with the second CSI-RS resource in the CSI-RS resource set, the WTRU may assign a higher priority to the CSI associated with the first CSI-RS resource in the CSI-RS resource set. A first CSI associated with a first CSI-RS resource in the CSI-RS resource set may have a higher rank value compared to a second CSI associated with a second CSI-RS resource in the CSI-RS resource set. As compared to the priority value assigned to the second CSI associated with the second CSI-RS resource in the CSI-RS resource set, the WTRU may assign a higher priority to the CSI associated with the first CSI-RS resource in the CSI-RS resource set. A first CSI associated with a first CSI-RS resource in the CSI-RS resource set may have a higher RSRP value compared to a second CSI associated with a second CSI-RS resource in the CSI-RS resource set. As compared to the priority value assigned to the second CSI associated with the second CSI-RS resource in the CSI-RS resource set, the WTRU may assign a higher priority to the CSI associated with the first CSI- RS resource in the CSI-RS resource set.

[0217] For Class-A CSI, the priority values to each CSI may be assigned based on the codebook types used to determine the CSI, based on the payload size of the CSI, based on the codebook parameters used for determination of the CSI, and based on the latency class of the CSI, as covered earlier with examples.

[0218] After determining CSI reports, the WTRU may send the CSI report in uplink resources allocated by the network, where the priority of CSI reporting may be as discussed earlier. For example, a high-priority CSI report may be reported, and a low-priority CSI report may be dropped and / or left for later transmission.

[0219] For Class-A CSI, one or more indications may be used. An indication may indicate a rank value for each of the CSI-RS resources in the selected subset of CSI-RS resources. An indication may indicate a CQI value (e.g., for a wideband CQI and for subband CQI(s)) associated with each of the CSI-RS resources in the selected subset of CSI-RS resources. An indication may indicate a PMI for each of the CSI-RS resources in the selected subset of CSI-RS resources. An indication may indicate an RSRP value for each of the CSI-RS resources in the selected subset of CSI-RS resources.

[0220] For Class-B CSI, one or more indications may be used. An indication may indicate a single aggregated rank value for all the selected CSI-RS resources. An indication may indicate a single aggregated CQI (e.g., wideband CQI(s) and / or subband CQI(s)) value for all the selected CSI-RS resources. An indication may indicate a single aggregated PMI (e.g., a single PMI for all the ports in the selected CSI-RS resources) for all the selected CSI-RS resources An indication may indicate a single aggregated RSRP value for all the selected CSI-RS resources.

[0221] Referring now to FIG. 2, an example procedure 200 that may be performed by a WTRU for channel state information (CSI) reporting for hybrid beamforming performed by a WTRU is illustratively depicted.

[0222] At 202, a WTRU may receive configuration information indicating one or more of a plurality of channel state information reference signal (CSI-RS) resources in a CSI-RS resource set or a target performance requirement. The configuration information may be provided via radio resource control (RRC)signaling, a medium access control-control element (MAC-CE), or downlink control information (DCI) and may include an indication of a CSI-RS resource selection criterion based on one or more of a target reference signal received power (RSRP) value, a target rank value, or a target channel quality indicator (CQI) value.

[0223] At 204, the WTRU may select one or more CSI-RS resources from the plurality of CSI-RS resources based on characteristics of the one or more CSI-RS resources and the target performance requirement. The selection may be performed based on one or more aggregated values corresponding to the CSI-RS resources in the CSI-RS resource set.

[0224] At 206, the WTRU may generate and transmit a CSI report, wherein the CSI report may comprise an indication of the one or more selected CSI-RS resources. The indication may include one or more of a rank value, CQI value, precoding matrix indicator (PM I), or RSRP value corresponding to the selected CSI- RS resources.

[0225] At 208, the selection of the one or more CSI-RS resources may be further refined based on one or more values. At 208a, the selection may be based on an aggregated RSRP value of the one or more CSI-RS resources meeting or exceeding a target RSRP value. For example, if a CSI-RS resource set includes multiple CSI-RS resources with individual RSRP values, the WTRU may sum these values and select a subset of CSI-RS resources where the aggregated RSRP value meets or exceeds the target RSRP value At 208b, the selection may be based on an aggregated CQI value of the one or more CSI-RS resources meeting or exceeding a target CQI value. The WTRU may determine a CQI index for each CSI- RS resource and may select a subset that achieves the required aggregated CQI value. At 208c, the selection may be based on an aggregated rank value of the one or more CSI-RS resources meeting or exceeding a target rank value. The WTRU may select CSI-RS resources that, when combined, meet the rank requirement for optimal transmission.

[0226] At 210, the WTRU may select one or more CSI-RS resources based on a received configuration or indication. The configuration or indication may specify a subset of CSI-RS resources to be prioritized for selection or a measurement-based selection criterion such as an RSRP threshold, a CQI threshold, or a rank threshold. The selection criterion may be applied based on one or more predefined rules to ensure efficient CSI-RS resource selection.

[0227] At 212, the WTRU may determine a respective CSI for each of the one or more selected CSI-RS resources. The CSI determination may be based on Class-A or Class-B CSI reporting. For Class-A CSI, the WTRU may determine a separate CSI for each selected CSI-RS resource, including individual rank, CQI, and PM I values. For Class-B CSI, the WTRU may determine a single aggregated CSI for all selected CSI- RS resources, where the CSI report may include a single aggregated rank, CQI, PMI, and / or RSRP value.

[0228] At 214, the WTRU may report the CSI associated with the one or more selected CSI-RS resources based on a priority level. The priority level may be assigned based on one or more of an RSRP value, a rank value, or a CQI value of the CSI. The WTRU may prioritize reporting CSI for CSI-RS resources with the highest RSRP, CQI, or rank values, ensuring that the most relevant CSI is reported while minimizing feedback overhead. Additionally, in some instances, the WTRU may determine the priority level based on the number of CSI-RS resources in the CSI-RS resource set, the number of CSI-RS antenna ports, or the number of CSI-RS resources in a selected subset.

Claims

CLAIMS1 . A wireless transmit / receive unit (WTRU) comprising: a processor configured to: receive configuration information, wherein the configuration information indicates one or more of a plurality of channel state information (CSI) reference signal (RS) resources in a CSI-RS resource set, and wherein the configuration information indicates a target performance requirement; select one or more CSI-RS resources from the plurality of CSI-RS resources based on characteristics of the one or more CSI-RS resources and the target performance requirement; and send a CSI report, wherein the CSI report comprises an indication of the one or more selected CSI- RS resources.

2. The WTRU of claim 1 , wherein the target performance requirement comprises one or more of a target reference signal received power (RSRP) value, a target rank value, or a target channel quality indicator (CQI) value.

3. The WTRU of claim 2, wherein the characteristics of the one or more CSI-RS resources comprise an aggregated RSRP value of the one or more CSI-RS resources, and wherein the processor is configured to select the one or more of CSI-RS resources based on the aggregated RSRP value being greater than or equal to the target RSRP value.

4. The WTRU of claim 2, wherein the characteristics of the one or more CSI-RS resources comprise an aggregated CQI value of the one or more CSI-RS resources, wherein the processor is configured to select the one or more CSI-RS resources based on the aggregated CQI value being greater than or equal to the target CQI value.

5. The WTRU of claim 2, wherein the characteristics of the one or more CSI-RS resources comprise an aggregated rank value of the one or more CSI-RS resources, wherein the processor is configured to select the one or more CSI-RS resources based on the aggregated rank value being greater than or equal to the target rank value.

6. The WTRU of claim 1 , wherein the processor is configured to:receive a CSI-RS resource selection criterion, wherein the CSI-RS resource selection criterion comprises one or more of a target reference signal received power (RSRP) value, a target rank value, or a target channel quality indicator (CQI) value; and select the one or more CSI-RS resources from the plurality of CSI-RS resources based on the CSI- RS resource selection criterion.

7. The WTRU of claim 6, wherein the processor is configured to: send the CSI report based on a priority level associated with the CSI report, wherein the processor is configured to determine the priority level based on one or more of an RSRP value, a rank value, or a CQI value of the CSI report.

8. The WTRU of claim 1 , wherein the one or more CSI-RS resources comprise a minimum number of CSI-RS resources capable of achieving one or more of: a maximum aggregated RSRP value that is greater than or equal to a target reference signal received power (RSRP) value; a maximum aggregated channel quality indicator (CQI) value that is greater than or equal to a target CQI value; or a maximum aggregated rank value that is greater than or equal to a target rank value.

9. The WTRU of claim 1 , wherein the indication of the one or more CSI-RS resources comprises an indication of one or more of: a respective rank value for each of the one or more CSI-RS resources; a respective channel quality indicator (CQI) value for each of the one or more CSI-RS resources; a respective precoding matrix indicator (PM I) for each of the one or more CSI-RS resources; or a respective reference signal received power (RSRP) value for each of the one or more CSI-RS resources.

10. The WTRU of claim 1, wherein the indication of the one or more CSI-RS resources comprises an indication of one or more of: an aggregated rank value for the one or more CSI-RS resources; an aggregated channel quality indicator (CQI) value for the one or more CSI-RS resources; an aggregated precoding matrix indicator (PMI) for the one or more CSI-RS resources; or an aggregated reference signal received power (RSRP) value for the one or more CSI-RS resources.

11. A method implemented by a wireless transmit / receive unit (WTRU), the method comprising: receiving configuration information, wherein the configuration information indicates one or more of a plurality of channel state information (CSI) reference signal (RS) resources in a CSI-RS resource set, and wherein the configuration information indicates a target performance requirement; selecting one or more CSI-RS resources from the plurality of CSI-RS resources based on characteristics of the one or more CSI-RS resources and the target performance requirement; and sending a CSI report, wherein the CSI report comprises an indication of the one or more selected CSI-RS resources.

12. The method of claim 11 , wherein the target performance requirement comprises one or more of a target reference signal received power (RSRP) value, a target rank value, or a target channel quality indicator (CQI) value.

13. The method of claim 12, wherein the characteristics of the one or more CSI-RS resources comprise an aggregated RSRP value of the one or more CSI-RS resources, and wherein the one or more CSI-RS resources are selected based on the aggregate RSRP value being greater than or equal to the target RSRP value14. The method of claim 12, wherein the characteristics of the one or more CSI-RS resources comprise an aggregated CQI value of the one or more CSI-RS resources, wherein the selection of the one or more CSI-RS resources is based on the aggregated CQI value being greater than or equal to the target CQI value.

15. The method of claim 12, wherein the characteristics of the one or more CSI-RS resources comprise an aggregated rank value of the one or more CSI-RS resources, wherein the selection of the one or more CSI-RS resources is based on the aggregated rank value being greater than or equal to the target rank value.

16. The method of claim 11 , further comprising: receiving a CSI-RS resource selection criterion, wherein the CSI-RS resource selection criterion comprises one or more of a target reference signal received power (RSRP) value, a target rank value, or a target channel quality indicator (CQI) value; andselecting the one or more CSI-RS resources from the plurality of CSI-RS resources based on the CSI-RS resource selection criterion.

17. The method of claim 16, further comprising: sending the CSI report based on a priority level associated with the CSI report, wherein the priority level is determined based on one or more of an RSRP value, a rank value, or a CQI value of the CSI report.

18. The method of claim 11 , wherein the one or more CSI-RS resources comprise a minimum number of CSI-RS resources capable of achieving one or more of: a maximum aggregated reference signal received power (RSRP) value that is greater than or equal to a target RSRP value, a maximum aggregated channel quality indicator (CQI) value that is greater than or equal to a target CQI value, or a maximum aggregated rank value that is greater than or equal to a target rank value.

19. The method of claim 1 1 , wherein the indication of the one or more CSI-RS resources comprises an indication of one or more of: a respective rank value for each of the one or more CSI-RS resources; a respective channel quality indicator (CQI) value for each of the one or more CSI-RS resources; a respective precoding matrix indicator (PM I) for each of the one or more CSI-RS resources; or a respective reference signal received power (RSRP) value for each of the one or more CSI-RS resources.

20. The method of claim 11 , wherein the indication of the one or more CSI-RS resources comprises an indication of one or more of: an aggregated rank value for the one or more CSI-RS resources; an aggregated channel quality indicator (CQI) value for the one or more CSI-RS resources; an aggregated precoding matrix indicator (PMI) for the one or more CSI-RS resources; or an aggregated reference signal received power (RSRP) value for the one or more CSI-RS resources.

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