DETERMINE CORRELATION WITH REGIONALIZED CSI RESOURCES

Abstract

The invention relates to a system, method, and instrument for determining co-occurrence with partitioned channel state information resources (CSI). The device can obtain information indicating which CSI reference signal resource (CSI-RS) is associated with the first set of CSI-RS ports and which CSI resource is associated with the second set of CSI-RS ports. The device can obtain CSI-RS in the first CSI-RS resource and which CSI-RS resource set. The device can determine the first measurement based on the CSI-RS obtained in the first CSI-RS resource and the second measurement based on the CSI-RS obtained in the second CSI-RS resource. The device can determine the first pre-code matrix indicator (PMI) based on the first measurement and the second PMI based on the second measurement. The device can send a CSI report to the network entity. The CSI report can indicate the first PMI and the second PMI.

Description

DETERMINATION OF CO-PHASING WITH PARTITIONED CSI RESOURCES CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No.63 / 546,428, filed October 30, 2023 the contents of which is incorporated by reference herein. BACKGROUND

[0002] Mobile communications using wireless communication continue to evolve. A fifth generation may be referred to as 5G. A previous (legacy) generation of mobile communication may be, for example, fourth generation (4G) long term evolution (LTE). SUMMARY

[0003] Systems, methods, devices, and instrumentalities are described herein related to the determination of co-phasing with partitioned channel state information (CSI) resources.

[0004] A device (e.g., a wireless transmit / receive unit (WTRU)) may receive information that indicates a first channel state information reference signal (CSI-RS) resource associated with a first set of CSI-RS ports and a second CSI-RS resource associated with a second set of CSI-RS ports. The device may receive a CSI-RS in the first CSI-RS resource and the second CSI-RS resource. The device may determine a first measurement based on the CSI-RS received in the first CSI-RS resource, and a second measurement based on the CSI-RS received in the second CSI-RS resource. The device may determine a first precoding matrix indicator (PMI) associated with the first CSI-RS resource based on the first measurement and a second PMI associated with the second CSI-RS resource based on the second measurement. The device may send, to a network entity, a channel state information (CSI) report, wherein the CSI report indicates the first PMI and the second PMI.

[0005] The first CSI-RS resource and the second CSI-RS resource may be in a (e.g., same) CSI-RS resource set. The CSI report may indicate a quantized co-phasing measurement between the first PMI and the second PMI.

[0006] The first CSI-RS resource may be in a first CSI-RS resource set. The second CSI-RS resource may be in a second CSI-RS resource set, different from the first CSI-RS resource set. The CSI report may indicate measured co-phasing across the first PMI and the second PMI.

[0007] The device may determine the first measurement based on a first polarization of CSI-RS ports in the first set of CSI-RS ports. The device may determine the second measurement based on a second polarization of CSI-RS ports in the second set of CSI-RS ports. The second polarization may be different from the first polarization.

[0008] The information may indicate a third CSI-RS resource associated with a third set of CSI-RS ports and a fourth CSI-RS resource associated with a fourth set of CSI-RS ports. The device may receive the CSI-RS in the third CSI-RS resource and the fourth CSI-RS resource. The device may determine a third measurement based on the CSI-RS received in the third CSI-RS resource, and a fourth measurement based on the CSI-RS received in the fourth CSI-RS resource. The device may determine a third PMI associated with the third CSI-RS resource based on the third measurement, and a fourth PMI associated with the fourth CSI-RS resource based on the fourth measurement. The CSI report may indicate the third PMI and the fourth PMI.

[0009] The device may determine, based on a time-based recursive pattern, which one or more CSI-RS resources, of the first CSI-RS resource and the second CSI-RS resource, in which to receive the CSI-RS.

[0010] The information may indicate a third CSI-RS resource associated with a third set of CSI-RS ports, the second CSI-RS resource and the third CSI-RS resource are multiplexed in at least one of time or frequency resources. The device may aggregate the second CSI-RS resource and the third CSI-RS resource to generate a combined CSI-RS resource. The device may determine the second measurement based on the CSI-RS received in the combined CSI-RS resource.

[0011] The CSI-RS may be a first CSI-RS. The CSI report may be a first CSI report. Based on the first CSI-RS resource, the second CSI-RS resource, and a pattern for assigning ports to CSI-RS resources, the device may determine a third CSI-RS resource associated with a third set of CSI-RS ports and a fourth CSI-RS resource associated with a fourth set of CSI-RS ports. The device may receive a second CSI-RS in the third CSI-RS resource and the fourth CSI-RS resource. The device may determine a third measurement based on the second CSI-RS received in the third CSI-RS resource, and a fourth measurement based on the second CSI-RS received in the fourth CSI-RS resource. The device may determine a third PMI associated with the third CSI-RS resource based on the third measurement, and a fourth PMI associated with the fourth CSI-RS resource based on the fourth measurement. The device may send, to the network entity, a second CSI report, wherein the second CSI report indicates the third PMI and the fourth PMI.

[0012] The first set of CSI-RS ports may include a first plurality of ports mapped to the first CSI-RS resource. The second set of CSI-RS ports may include a second plurality of ports mapped to the second CSI-RS resource. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Furthermore, like reference numerals in the figures indicate like elements, and wherein:

[0014] FIG.1A is a system diagram illustrating an example communications system in which one or more disclosed embodiments may be implemented.

[0015] FIG.1B is a system diagram illustrating an example wireless transmit / receive unit (WTRU) that may be used within the communications system illustrated in FIG.1A according to an embodiment.

[0016] 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.

[0017] FIG.1D is a system diagram illustrating a further example RAN and a further example CN that may be used within the communications system illustrated in FIG.1A according to an embodiment.

[0018] FIGs.2A and 2B illustrate an example technique for a WTRU to search and report a precoding matrix indicator (PMI) from a restricted codebook subset.

[0019] FIG.3 illustrates an example technique for a WTRU to determine co-phasing with partitioned channel state information (CSI) resources.

[0020] FIG.4 illustrates an example technique for a WTRU to determine PMI and co-phasing information associated with CSI resources.

[0021] FIG.5 illustrates an example of a technique for identifying a subset of CSI ports based on an associated transmission configuration indicator (TCI) state.

[0022] FIG.6 illustrates an example technique for CSI reporting. DETAILED DESCRIPTION

[0023] FIG.1A is a diagram illustrating an example communications system 100 in which one or more disclosed embodiments may be implemented. The communications system 100 may be a multiple access system that provides content, such as voice, data, video, messaging, broadcast, etc., to multiple wireless users. The communications system 100 may enable multiple wireless users to access such content through the sharing of system resources, including wireless bandwidth. For example, the communications systems 100 may employ one or more channel access methods, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonalFDMA (OFDMA), single-carrier FDMA (SC-FDMA), zero-tail unique-word DFT-Spread OFDM (ZT UW DTS-s OFDM), unique word OFDM (UW-OFDM), resource block-filtered OFDM, filter bank multicarrier (FBMC), and the like.

[0024] As shown in FIG.1A, the communications system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, a RAN 104 / 113, a CN 106 / 115, a public switched telephone network (PSTN) 108, the Internet 110, and other networks 112, though it will be appreciated that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network elements. Each of the WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and / or communicate in a wireless environment. By way of example, the WTRUs 102a, 102b, 102c, 102d, any of which may be referred to as a “station” and / or a “STA”, may be configured to transmit and / or receive wireless signals and may include a user equipment (WTRU), a mobile station, a fixed or mobile subscriber unit, a subscription-based unit, a pager, a cellular telephone, a personal digital assistant (PDA), a smartphone, a laptop, a netbook, a personal computer, a wireless sensor, a hotspot or Mi-Fi device, an Internet of Things (IoT) device, a watch or other wearable, a head-mounted display (HMD), a vehicle, a drone, a medical device and applications (e.g., remote surgery), an industrial device and applications (e.g., a robot and / or other wireless devices operating in an industrial and / or an automated processing chain contexts), a consumer electronics device, a device operating on commercial and / or industrial wireless networks, and the like. Any of the WTRUs 102a, 102b, 102c and 102d may be interchangeably referred to as a WTRU.

[0025] The communications systems 100 may also include a base station 114a and / or a base station 114b. Each of the base stations 114a, 114b may be any type of device configured to wirelessly interface with at least one of the WTRUs 102a, 102b, 102c, 102d to facilitate access to one or more communication networks, such as the CN 106 / 115, the Internet 110, and / or the other networks 112. By way of example, the base stations 114a, 114b may be a base transceiver station (BTS), a Node-B, an eNode B, a Home Node B, a Home eNode B, a gNB, a NR NodeB, a site controller, an access point (AP), a wireless router, and the like. While the base stations 114a, 114b are each depicted as a single element, it will be appreciated that the base stations 114a, 114b may include any number of interconnected base stations and / or network elements.

[0026] 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 acombination of licensed and unlicensed spectrum. A cell may provide coverage for a wireless service to a specific geographical area that may be relatively fixed or that may change over time. The cell may further be divided into cell sectors. For example, the cell associated with the base station 114a may be divided into three sectors. Thus, in one embodiment, the base station 114a may include three transceivers, i.e., one for each sector of the cell. In an embodiment, the base station 114a may employ multiple-input multiple output (MIMO) technology and may utilize multiple transceivers for each sector of the cell. For example, beamforming may be used to transmit and / or receive signals in desired spatial directions.

[0027] 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).

[0028] More specifically, as noted above, the communications system 100 may be a multiple access system and may employ one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and the like. For example, the base station 114a in the RAN 104 / 113 and the WTRUs 102a, 102b, 102c may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may establish the air interface 115 / 116 / 117 using wideband CDMA (WCDMA). WCDMA may include communication protocols such as High-Speed Packet Access (HSPA) and / or Evolved HSPA (HSPA+). HSPA may include High-Speed Downlink (DL) Packet Access (HSDPA) and / or High-Speed UL Packet Access (HSUPA).

[0029] 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).

[0030] 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).

[0031] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement multiple radio access technologies. For example, the base station 114a and the WTRUs 102a, 102b, 102c may implement LTE radio access and NR radio access together, for instance using dual connectivity (DC) principles. Thus, the air interface utilized by WTRUs 102a, 102b, 102c may be characterized by multiple types of radio access technologies and / or transmissions sent to / from multiple types of base stations (e.g., a eNB and a gNB).

[0032] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement radio technologies such as IEEE 802.11 (i.e., Wireless Fidelity (WiFi), IEEE 802.16 (i.e., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA20001X, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile communications (GSM), Enhanced Data rates for GSM Evolution (EDGE), GSM EDGE (GERAN), and the like.

[0033] The base station 114b in FIG.1A may be a wireless router, Home Node B, Home eNode B, or access point, for example, and may utilize any suitable RAT for facilitating wireless connectivity in a localized area, such as a place of business, a home, a vehicle, a campus, an industrial facility, an air corridor (e.g., for use by drones), a roadway, and the like. In one embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.11 to establish a wireless local area network (WLAN). In an embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.15 to establish a wireless personal area network (WPAN). In yet another embodiment, the base station 114b and the WTRUs 102c, 102d may utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR etc.) to establish a picocell or femtocell. As shown in FIG.1A, the base station 114b may have a direct connection to the Internet 110. Thus, the base station 114b may not be required to access the Internet 110 via the CN 106 / 115.

[0034] The RAN 104 / 113 may be in communication with the CN 106 / 115, which may be any type of network configured to provide voice, data, applications, and / or voice over internet protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. The data may have varying quality of service (QoS) requirements, such as differing throughput requirements, latency requirements, error tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, and the like. The CN 106 / 115 may provide call control, billing services, mobile location-based services, pre-paid calling, Internet connectivity, video distribution, etc., and / or perform high-level security functions, such as user authentication. Although not shown in FIG.1A, it will be appreciated that the RAN 104 / 113 and / or the CN 106 / 115 may be in direct or indirect communication with other RANs that employ the same RAT as the RAN 104 / 113 or a different RAT. For example, in addition to being connected to the RAN 104 / 113, which may be utilizing a NR radio technology, the CN 106 / 115 may also be in communication with another RAN (not shown) employing a GSM, UMTS, CDMA 2000, WiMAX, E-UTRA, or WiFi radio technology.

[0035] The CN 106 / 115 may also serve as a gateway for the WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the Internet 110, and / or the other networks 112. The PSTN 108 may include circuit- switched telephone networks that provide plain old telephone service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices that use commoncommunication protocols, such as the transmission control protocol (TCP), user datagram protocol (UDP) and / or the internet protocol (IP) in the TCP / IP internet protocol suite. The networks 112 may include wired and / or wireless communications networks owned and / or operated by other service providers. For example, the networks 112 may include another CN connected to one or more RANs, which may employ the same RAT as the RAN 104 / 113 or a different RAT.

[0036] 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.

[0037] FIG.1B is a system diagram illustrating an example WTRU 102. As shown in FIG.1B, the WTRU 102 may include a processor 118, a transceiver 120, a transmit / receive element 122, a speaker / microphone 124, a keypad 126, a display / touchpad 128, non-removable memory 130, removable memory 132, a power source 134, a global positioning system (GPS) chipset 136, and / or other peripherals 138, among others. It will be appreciated that the WTRU 102 may include any sub-combination of the foregoing elements while remaining consistent with an embodiment.

[0038] The processor 118 may be a general purpose processor, a special purpose processor, a conventional processor, a digital signal processor (DSP), a plurality of microprocessors, one or more microprocessors in association with a DSP core, a controller, a microcontroller, Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs) circuits, any other type of integrated circuit (IC), a state machine, and the like. The processor 118 may perform signal coding, data processing, power control, input / output processing, and / or any other functionality that enables the WTRU 102 to operate in a wireless environment. The processor 118 may be coupled to the transceiver 120, which may be coupled to the transmit / receive element 122. While FIG.1B depicts the processor 118 and the transceiver 120 as separate components, it will be appreciated that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip.

[0039] The transmit / receive element 122 may be configured to transmit signals to, or receive signals from, a base station (e.g., the base station 114a) over the air interface 116. For example, in one embodiment, the transmit / receive element 122 may be an antenna configured to transmit and / or receive RF signals. In an embodiment, the transmit / receive element 122 may be an emitter / detector configured to transmit and / or receive IR, UV, or visible light signals, for example. In yet another embodiment, the transmit / receive element 122 may be configured to transmit and / or receive both RF and light signals. It willbe appreciated that the transmit / receive element 122 may be configured to transmit and / or receive any combination of wireless signals.

[0040] Although the transmit / receive element 122 is depicted in FIG.1B as a single element, the WTRU 102 may include any number of transmit / receive elements 122. More specifically, the WTRU 102 may employ MIMO technology. Thus, in one embodiment, the WTRU 102 may include two or more transmit / receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals over the air interface 116.

[0041] 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.

[0042] The processor 118 of the WTRU 102 may be coupled to, and may receive user input data from, the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128 (e.g., a liquid crystal display (LCD) display unit or organic light-emitting diode (OLED) display unit). The processor 118 may also output user data to the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128. In addition, the processor 118 may access information from, and store data in, any type of suitable memory, such as the non-removable memory 130 and / or the removable memory 132. The non-removable memory 130 may include random-access memory (RAM), read-only memory (ROM), a hard disk, or any other type of memory storage device. The removable memory 132 may include a subscriber identity module (SIM) card, a memory stick, a secure digital (SD) memory card, and the like. In other embodiments, the processor 118 may access information from, and store data in, memory that is not physically located on the WTRU 102, such as on a server or a home computer (not shown).

[0043] 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.

[0044] 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 willbe appreciated that the WTRU 102 may acquire location information by way of any suitable location- determination method while remaining consistent with an embodiment.

[0045] The processor 118 may further be coupled to other peripherals 138, which may include one or more software and / or hardware modules that provide additional features, functionality and / or wired or wireless connectivity. For example, the peripherals 138 may include an accelerometer, an e-compass, a satellite transceiver, a digital camera (for photographs and / or video), a universal serial bus (USB) port, a vibration device, a television transceiver, a hands free headset, a Bluetooth® module, a frequency modulated (FM) radio unit, a digital music player, a media player, a video game player module, an Internet browser, a Virtual Reality and / or Augmented Reality (VR / AR) device, an activity tracker, and the like. The peripherals 138 may include one or more sensors, the sensors may be one or more of a gyroscope, an accelerometer, a hall effect sensor, a magnetometer, an orientation sensor, a proximity sensor, a temperature sensor, a time sensor; a geolocation sensor; an altimeter, a light sensor, a touch sensor, a magnetometer, a barometer, a gesture sensor, a biometric sensor, and / or a humidity sensor.

[0046] The WTRU 102 may include a full duplex radio for which transmission and reception of some or all of the signals (e.g., associated with particular subframes for both the UL (e.g., for transmission) and downlink (e.g., for reception) may be concurrent and / or simultaneous. The full duplex radio may include an interference management unit to reduce and or substantially eliminate self-interference via either hardware (e.g., a choke) or signal processing via a processor (e.g., a separate processor (not shown) or via processor 118). In an embodiment, the WRTU 102 may include a half-duplex radio for which transmission and reception of some or all of the signals (e.g., associated with particular subframes for either the UL (e.g., for transmission) or the downlink (e.g., for reception)).

[0047] FIG.1C is a system diagram illustrating the RAN 104 and the CN 106 according to an embodiment. As noted above, the RAN 104 may employ an E-UTRA radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 104 may also be in communication with the CN 106.

[0048] The RAN 104 may include eNode-Bs 160a, 160b, 160c, though it will be appreciated that the RAN 104 may include any number of eNode-Bs while remaining consistent with an embodiment. The eNode-Bs 160a, 160b, 160c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In one embodiment, the eNode-Bs 160a, 160b, 160c may implement MIMO technology. Thus, the eNode-B 160a, for example, may use multiple antennas to transmit wireless signals to, and / or receive wireless signals from, the WTRU 102a.

[0049] Each of the eNode-Bs 160a, 160b, 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling ofusers in the UL and / or DL, and the like. As shown in FIG.1C, the eNode-Bs 160a, 160b, 160c may communicate with one another over an X2 interface.

[0050] The CN 106 shown in FIG.1C may include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (or PGW) 166. While each of the foregoing elements are depicted as part of the CN 106, it will be appreciated that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0051] The MME 162 may be connected to each of the eNode-Bs 162a, 162b, 162c in the RAN 104 via an S1 interface and may serve as a control node. For example, the MME 162 may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, bearer activation / deactivation, selecting a particular serving gateway during an initial attach of the WTRUs 102a, 102b, 102c, and the like. The MME 162 may provide a control plane function for switching between the RAN 104 and other RANs (not shown) that employ other radio technologies, such as GSM and / or WCDMA.

[0052] 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.

[0053] 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.

[0054] The CN 106 may facilitate communications with other networks. For example, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to circuit-switched networks, such as the PSTN 108, to facilitate communications between the WTRUs 102a, 102b, 102c and traditional land-line communications devices. For example, the CN 106 may include, or may communicate with, an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that serves as an interface between the CN 106 and the PSTN 108. In addition, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to the other networks 112, which may include other wired and / or wireless networks that are owned and / or operated by other service providers.

[0055] Although the WTRU is described in FIGS.1A-1D as a wireless terminal, it is contemplated that in certain representative embodiments that such a terminal may use (e.g., temporarily or permanently) wired communication interfaces with the communication network.

[0056] In representative embodiments, the other network 112 may be a WLAN.

[0057] A WLAN in Infrastructure Basic Service Set (BSS) mode may have an Access Point (AP) for the BSS and one or more stations (STAs) associated with the AP. The AP may have an access or an interface to a Distribution System (DS) or another type of wired / wireless network that carries traffic in to and / or out of the BSS. Traffic to STAs that originates from outside the BSS may arrive through the AP and may be delivered to the STAs. Traffic originating from STAs to destinations outside the BSS may be sent to the AP to be delivered to respective destinations. Traffic between STAs within the BSS may be sent through the AP, for example, where the source STA may send traffic to the AP and the AP may deliver the traffic to the destination STA. The traffic between STAs within a BSS may be considered and / or referred to as peer-to- peer traffic. The peer-to-peer traffic may be sent between (e.g., directly between) the source and destination STAs with a direct link setup (DLS). In certain representative embodiments, the DLS may use an 802.11e DLS or an 802.11z tunneled DLS (TDLS). A WLAN using an Independent BSS (IBSS) mode may not have an AP, and the STAs (e.g., all of the STAs) within or using the IBSS may communicate directly with each other. The IBSS mode of communication may sometimes be referred to herein as an “ad- hoc” mode of communication.

[0058] When using the 802.11ac infrastructure mode of operation or a similar mode of operations, the AP may transmit a beacon on a fixed channel, such as a primary channel. The primary channel may be a fixed width (e.g., 20 MHz wide bandwidth) or a dynamically set width via signaling. The primary channel may be the operating channel of the BSS and may be used by the STAs to establish a connection with the AP. In certain representative embodiments, Carrier Sense Multiple Access with Collision Avoidance (CSMA / CA) may be implemented, for example in in 802.11 systems. For CSMA / CA, the STAs (e.g., every STA), including the AP, may sense the primary channel. If the primary channel is sensed / detected and / or determined to be busy by a particular STA, the particular STA may back off. One STA (e.g., only one station) may transmit at any given time in a given BSS.

[0059] 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.

[0060] Very High Throughput (VHT) STAs may support 20MHz, 40 MHz, 80 MHz, and / or 160 MHz wide channels. The 40 MHz, and / or 80 MHz, channels may be formed by combining contiguous 20 MHz channels. A 160 MHz channel may be formed by combining 8 contiguous 20 MHz channels, or by combining two non-contiguous 80 MHz channels, which may be referred to as an 80+80 configuration. For the 80+80 configuration, the data, after channel encoding, may be passed through a segment parser that may divide the data into two streams. Inverse Fast Fourier Transform (IFFT) processing, and time domain processing, may be done on each stream separately. The streams may be mapped on to the two 80 MHzchannels, and the data may be transmitted by a transmitting STA. At the receiver of the receiving STA, the above described operation for the 80+80 configuration may be reversed, and the combined data may be sent to the Medium Access Control (MAC).

[0061] Sub 1 GHz modes of operation are supported by 802.11af and 802.11ah. The channel operating bandwidths, and carriers, are reduced in 802.11af and 802.11ah relative to those used in 802.11n, and 802.11ac.802.11af supports 5 MHz, 10 MHz and 20 MHz bandwidths in the TV White Space (TVWS) spectrum, and 802.11ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths using non- TVWS spectrum. According to a representative embodiment, 802.11ah may support Meter Type Control / Machine-Type Communications, such as MTC devices in a macro coverage area. MTC devices may have certain capabilities, for example, limited capabilities including support for (e.g., only support for) certain and / or limited bandwidths. The MTC devices may include a battery with a battery life above a threshold (e.g., to maintain a very long battery life).

[0062] WLAN systems, which may support multiple channels, and channel bandwidths, such as 802.11n, 802.11ac, 802.11af, and 802.11ah, include a channel which may be designated as the primary channel. The primary channel may have a bandwidth equal to the largest common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel may be set and / or limited by a STA, from among all STAs in operating in a BSS, which supports the smallest bandwidth operating mode. In the example of 802.11ah, the primary channel may be 1 MHz wide for STAs (e.g., MTC type devices) that support (e.g., only support) a 1 MHz mode, even if the AP, and other STAs in the BSS support 2 MHz, 4 MHz, 8 MHz, 16 MHz, and / or other channel bandwidth operating modes. Carrier sensing and / or Network Allocation Vector (NAV) settings may depend on the status of the primary channel. If the primary channel is busy, for example, due to a STA (which supports only a 1 MHz operating mode), transmitting to the AP, the entire available frequency bands may be considered busy even though a majority of the frequency bands remains idle and may be available.

[0063] In the United States, the available frequency bands, which may be used by 802.11ah, are from 902 MHz to 928 MHz. In Korea, the available frequency bands are from 917.5 MHz to 923.5 MHz. In Japan, the available frequency bands are from 916.5 MHz to 927.5 MHz. The total bandwidth available for 802.11ah is 6 MHz to 26 MHz depending on the country code.

[0064] FIG.1D is a system diagram illustrating the RAN 113 and the CN 115 according to an embodiment. As noted above, the RAN 113 may employ an NR radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 113 may also be in communication with the

[0065] The RAN 113 may include gNBs 180a, 180b, 180c, though it will be appreciated that the RAN 113 may include any number of gNBs while remaining consistent with an embodiment. The gNBs 180a, 180b, 180c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In one embodiment, the gNBs 180a, 180b, 180c may implement MIMO technology. For example, gNBs 180a, 108b may utilize beamforming to transmit signals to and / or receive signals from the gNBs 180a, 180b, 180c. Thus, the gNB 180a, for example, may use multiple antennas to transmit wireless signals to, and / or receive wireless signals from, the WTRU 102a. In an embodiment, the gNBs 180a, 180b, 180c may implement carrier aggregation technology. For example, the gNB 180a may transmit multiple component carriers to the WTRU 102a (not shown). A subset of these component carriers may be on unlicensed spectrum while the remaining component carriers may be on licensed spectrum. In an embodiment, the gNBs 180a, 180b, 180c may implement Coordinated Multi-Point (CoMP) technology. For example, WTRU 102a may receive coordinated transmissions from gNB 180a and gNB 180b (and / or gNB 180c).

[0066] The WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using transmissions associated with a scalable numerology. For example, the OFDM symbol spacing and / or OFDM subcarrier spacing may vary for different transmissions, different cells, and / or different portions of the wireless transmission spectrum. The WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using subframe or transmission time intervals (TTIs) of various or scalable lengths (e.g., containing varying number of OFDM symbols and / or lasting varying lengths of absolute time).

[0067] The gNBs 180a, 180b, 180c may be configured to communicate with the WTRUs 102a, 102b, 102c in a standalone configuration and / or a non-standalone configuration. In the standalone configuration, WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c without also accessing other RANs (e.g., such as eNode-Bs 160a, 160b, 160c). In the standalone configuration, WTRUs 102a, 102b, 102c may utilize one or more of gNBs 180a, 180b, 180c as a mobility anchor point. In the standalone configuration, WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using signals in an unlicensed band. In a non-standalone configuration WTRUs 102a, 102b, 102c may communicate with / connect to gNBs 180a, 180b, 180c while also communicating with / connecting to another RAN such as eNode-Bs 160a, 160b, 160c. For example, WTRUs 102a, 102b, 102c may implement DC principles to communicate with one or more gNBs 180a, 180b, 180c and one or more eNode-Bs 160a, 160b, 160c substantially simultaneously. In the non-standalone configuration, eNode-Bs 160a, 160b, 160c may serve as a mobility anchor for WTRUs 102a, 102b, 102c and gNBs 180a, 180b, 180c may provide additional coverage and / or throughput for servicing WTRUs 102a, 102b, 102c.

[0068] Each of the gNBs 180a, 180b, 180c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the UL and / or DL, support of network slicing, dual connectivity, interworking between NR and E- UTRA, routing of user plane data towards User Plane Function (UPF) 184a, 184b, routing of control plane information towards Access and Mobility Management Function (AMF) 182a, 182b and the like. As shown in FIG.1D, the gNBs 180a, 180b, 180c may communicate with one another over an Xn interface.

[0069] The CN 115 shown in FIG.1D may include at least one AMF 182a, 182b, at least one UPF 184a,184b, at least one Session Management Function (SMF) 183a, 183b, and possibly a Data Network (DN) 185a, 185b. While each of the foregoing elements are depicted as part of the CN 115, it will be appreciated that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0070] The AMF 182a, 182b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via an N2 interface and may serve as a control node. For example, the AMF 182a, 182b may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, support for network slicing (e.g., handling of different PDU sessions with different requirements), selecting a particular SMF 183a, 183b, management of the registration area, termination of NAS signaling, mobility management, and the like. Network slicing may be used by the AMF 182a, 182b in order to customize CN support for WTRUs 102a, 102b, 102c based on the types of services being utilized WTRUs 102a, 102b, 102c. For example, different network slices may be established for different use cases such as services relying on ultra-reliable low latency (URLLC) access, services relying on enhanced massive mobile broadband (eMBB) access, services for machine type communication (MTC) access, and / or the like. The AMF 162 may provide a control plane function for switching between the RAN 113 and other RANs (not shown) that employ other radio technologies, such as LTE, LTE-A, LTE-A Pro, and / or non-3GPP access technologies such as WiFi.

[0071] The SMF 183a, 183b may be connected to an AMF 182a, 182b in the CN 115 via an N11 interface. The SMF 183a, 183b may also be connected to a UPF 184a, 184b in the CN 115 via an N4 interface. The SMF 183a, 183b may select and control the UPF 184a, 184b and configure the routing of traffic through the UPF 184a, 184b. The SMF 183a, 183b may perform other functions, such as managing and allocating WTRU IP address, managing PDU sessions, controlling policy enforcement and QoS, providing downlink data notifications, and the like. A PDU session type may be IP-based, non-IP based, Ethernet-based, and the like.

[0072] The UPF 184a, 184b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via an N3 interface, which may provide the WTRUs 102a, 102b, 102c with access to packet- switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b,102c and IP-enabled devices. The UPF 184, 184b may perform other functions, such as routing and forwarding packets, enforcing user plane policies, supporting multi-homed PDU sessions, handling user plane QoS, buffering downlink packets, providing mobility anchoring, and the like.

[0073] The CN 115 may facilitate communications with other networks. For example, the CN 115 may include, or may communicate with, an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that serves as an interface between the CN 115 and the PSTN 108. In addition, the CN 115 may provide the WTRUs 102a, 102b, 102c with access to the other networks 112, which may include other wired and / or wireless networks that are owned and / or operated by other service providers. In one embodiment, the WTRUs 102a, 102b, 102c may be connected to a local Data Network (DN) 185a, 185b through the UPF 184a, 184b via the N3 interface to the UPF 184a, 184b and an N6 interface between the UPF 184a, 184b and the DN 185a, 185b.

[0074] In view of Figures 1A-1D, and the corresponding description of Figures 1A-1D, one or more, or all, of the functions described herein with regard to one or more of: WTRU 102a-d, Base Station 114a-b, eNode-B 160a-c, MME 162, SGW 164, PGW 166, gNB 180a-c, AMF 182a-b, UPF 184a-b, SMF 183a-b, DN 185a-b, and / or any other device(s) described herein, may be performed by one or more emulation devices (not shown). The emulation devices may be one or more devices configured to emulate one or more, or all, of the functions described herein. For example, the emulation devices may be used to test other devices and / or to simulate network and / or WTRU functions.

[0075] 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.

[0076] 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.

[0077] In examples (e.g., in multiple input multiple output (MIMO)), the maximum number of CSI-RS ports may increase from 32 to 64 with high probability (e.g., to efficiently measure the channel and provide narrower beam for each user).

[0078] A larger antenna array (e.g., with more transmission (TX)) for higher-order spatial multiplexing may be used (e.g., for multi-user MIMO (MU-MIMO)). A narrower beam (e.g., and consequently higher throughput) may be used for multiple users. Codebook restriction may be used to provide less overhead.

[0079] Multiple (e.g., 64) CSI-RS ports may be used. In some examples, the number of CSI-RS ports may be upper bounded to 32. To provide more TX for higher-order spatial multiplexing (e.g., for MU- MIMO), the upper bound may be increased to 64 ports. Increasing the number of CSI-RS ports may cause CSI feedback overhead and complexity at a WTRU to increase. CSI-RS resources may be designed with limited overhead.

[0080] CSI-RS ports may be upper bounded (e.g., by 64 ports). A WTRU may receive CSI-RS with 64 ports configuration with a grid-of-beams (GoB). The WTRU may receive a PUCCH resource configuration. The WTRU may measure the channel with 64 CSI-RS ports. The WTRU may report a precoding matrix indicator (PMI), rank indicator (RI), and / or channel quality indicator (CQI) to a network entity (e.g., gNB). The WTRU may select the best beam. The WTRU may report the best beam to the gNB. For example, the WTRU may determine a first cost associated with a third beam in the second search space and a second cost associated with a fourth beam in the second search space. The WTRU may select the third beam or the fourth beam (e.g., as the second beam) based on the first cost and the second cost.

[0081] The number of CSI-RS resources may be upper bounded by 32 ports. To serve a greater number of WTRUs with narrower beams, the upper bound may be increased to 64 ports. As the array grows, the spatial properties may no longer be uniform across the array (e.g., from the WTRU’s point of view). The WTRU may see more than two separate analog beams from the gNB. A (e.g., single) analog beam may not be an accurate representation for the whole array.

[0082] Increasing the maximum number of CSI-RS ports to 64 may have one or more effects. Techniques may be designed in such a way to reduce feedback overhead. CSI-RS ports may be partitioned to assist measuring the co-phasing among the ports. The ports (e.g., all the ports) of the array may be efficiently measured (e.g., without new designs or procedures).

[0083] As used herein, the terms ‘a’ and ‘an’ and similar phrases are to be interpreted as ‘one or more’ and ‘at least one’. Similarly, any term which ends with the suffix ‘(s)’ is to be interpreted as ‘one or more’ and ‘at least one’. The term ‘may’ is to be interpreted as ‘may, for example’.

[0084] A sign, symbol, or mark of forward slash ‘ / ’ is to be interpreted as ‘and / or’ unless particularly mentioned otherwise (e.g., ‘A / B’ may imply ‘A and / or B’).

[0085] An example definition of beam is provided herein. A WTRU may transmit or receive a physical channel or reference signal according to at least one spatial domain filter. The term “beam” may be used to refer to a spatial domain filter.

[0086] The WTRU may transmit a physical channel or signal using a spatial domain filter (e.g., the same spatial domain filter as the spatial domain filter used for receiving an RS, such as CSI-RS, or a synchronization signal (SS) block). The WTRU transmission may be referred to as “target.” The received RS or SS block may be referred to as “reference” or “source.” In this case, the WTRU may be said to transmit the target physical channel or signal according to a spatial relation with a reference to such RS or SS block.

[0087] The WTRU may transmit a first physical channel or signal according to a spatial domain filter (e.g., the same spatial domain filter as the spatial domain filter used for transmitting a second physical channel or signal). The first and second transmissions may be referred to as “target” and “reference” (or “source”), respectively. In such case, the WTRU may be said to transmit the first (target) physical channel or signal according to a spatial relation with a reference to the second (reference) physical channel or signal.

[0088] A spatial relation may be implicit, configured by RRC, or signaled by MAC CE or DCI. For example, a WTRU may implicitly transmit PUSCH and DM-RS of PUSCH according to a spatial domain filter (e.g., the same spatial domain filter as an SRS indicated by an SRS resource indicator (SRI) indicated in DCI or configured by RRC). In another example, a spatial relation may be configured by RRC for an SRI or signaled by MAC CE for a PUCCH. The spatial relation may be referred to as a “beam indication.”

[0089] The WTRU may receive a first (target) downlink channel or signal according to the same spatial domain filter or spatial reception parameter as a second (reference) downlink channel or signal. For example, the association may exist between a physical channel such as PDCCH or PDSCH and its respective DM-RS. If the first and second signals are reference signals, the association may exist if the WTRU is configured with a quasi-colocation (QCL) assumption type D between corresponding antenna ports. Such association may be configured as a transmission configuration indicator (TCI) state. A WTRU may receive an indication of an association between a CSI-RS or SS block and a DM-RS by an index to a set of TCI states configured by RRC and / or signaled by MAC CE. The indication may be referred to as a “beam indication.”

[0090] Feature(s) associated with unified TCI are provided herein. A unified TCI (e.g., a common TCI, a common beam, a common RS, etc.) may refer to a beam / RS to be (e.g., simultaneously) used for multiple physical channels / signals. The term “TCI” may refer to a TCI state that includes at least one source RS to provide a reference (e.g., WTRU assumption) for determining QCL and / or spatial filter.

[0091] A WTRU may receive (e.g., from a gNB) an indication of a first unified TCI to be used / applied for a downlink control channel (e.g., PDCCH) and a downlink shared channel (e.g., PDSCH) (e.g., and a downlink RS). The source reference signal(s) in the first unified TCI may provide common QCL information at least for WTRU-dedicated reception on the PDSCH and one or more (e.g., all or subset of) CORESETs in a component carrier (CC). The WTRU may receive (e.g., from a gNB) an indication of a second unified TCI to be used / applied for an uplink control channel (e.g., PUCCH) and an uplink shared channel (e.g., PUSCH) (e.g., and an uplink RS). The source reference signal(s) in the second unified TCI may provide a reference for determining common UL TX spatial filter(s) at least for dynamic-grant / configured-grant based PUSCH and one or more (e.g., all or subset of) dedicated PUCCH resources in a CC.

[0092] The WTRU may be configured with a first mode for unified TCI (e.g., SeparateDLULTCI mode). An indicated unified TCI (e.g., the first unified TCI or the second unified TCI) may be applicable for downlink (e.g., based on the first unified TCI) and / or uplink (e.g., based on the second unified TCI).

[0093] The WTRU may receive (e.g., from a gNB) an indication of a second unified TCI to be used / applied commonly for a PDCCH, a PDSCH, a PUCCH, and a PUSCH (and a DL RS and / or a UL RS).

[0094] The WTRU may be configured with a second mode for unified TCI (e.g., JointTCI mode). An indicated unified TCI (e.g., the third unified TCI) may be applicable for downlink and uplink (e.g., based on the third unified TCI).

[0095] The WTRU may determine a TCI state applicable to a transmission or reception by determining a unified TCI state instance applicable to the transmission or reception. The WTRU may determine a TCI state corresponding to the unified TCI state instance. A transmission may include (e.g., at least) PUCCH, PUSCH, and SRS. A reception may include (e.g., at least) PDCCH, PDSCH, and CSI-RS. A unified TCI state instance may be referred to TCI state group, TCI state process, unified TCI pool, a group of TCI states, a set of time-domain instances / stamps / slots / symbols, and / or a set of frequency-domain instances / RBs / subbands, etc. A unified TCI state instance may be equivalent to, or identified with, a control resource set (CORESET) pool identity (e.g., CORESETPoolIndex, a TRP indicator, and / or the like).

[0096] As used herein, unified TCI may be used interchangeably with one or more of unified TCI-states, unified TCI instance, TCI, and TCI-state (e.g., while remaining consistent within this disclosure).

[0097] Feature(s) associated with a transmission / reception point (TRP) and multi-TRP (MTRP or M- TRP) are provided herein.

[0098] As used herein, a TRP may be interchangeably used with one or more of transmission point (TP), reception point (RP), radio remote head (RRH), distributed antenna (DA), base station (BS), a sector (e.g., of a BS), a cell (e.g., a geographical cell area served by a BS), a CSI-RS resource set (e.g., whileremaining consistent within this disclosure). As used herein, multi-TRP may be interchangeably used with one or more of MTRP, M-TRP, and multiple TRPs (e.g., while remaining consistent within this disclosure).

[0099] Example configuration(s) of TRP(s), SRI(s), and pathloss (PL) reference RS(s) are provided herein.

[0100] A WTRU may be configured with (or may receive configuration of) one or more TRPs (e.g., to which the WTRU may transmit and / or from which the WTRU may receive). The WTRU may be configured with one or more TRPs for one or more cells. A cell may be a serving cell, secondary cell, and / or the like.

[0101] A WTRU may be configured with at least one RS (e.g., for the purpose of channel measurement). This RS may be denoted as a channel measurement resource (CMR). The CMR may include a CSI-RS, SSB, or other downlink RS (e.g., transmitted from the TRP to a WTRU). The CMR may be configured or associated with a TCI state. The WTRU may be configured with a CMR group (e.g., where CMRs transmitted from the same TRP may be configured). Each group may be identified by a CMR group index (e.g., group 1). A WTRU may be configured with a (e.g., one) CMR group per TRP. The WTRU may receive a linkage between a (e.g., one) CMR group index and another CMR group index, or between a (e.g., one) RS index from a (e.g., one) CMR group and another RS index from another group.

[0102] A WTRU may be configured with (or receive configuration of) one or more PL reference groups (e.g., sets) and / or one or more SRS groups, SRS resource indicator (SRI), or SRS resource sets.

[0103] A PL reference group may correspond to, or may be associated with, a TRP. A PL reference group may include, identify, correspond to, or be associated with one or more TCI states, SRIs, reference signal sets (e.g., CSI-RS set, SRI sets), CORESET index, and / or reference signals (e.g., CSI-RS, SSB).

[0104] A WTRU may receive a configuration (e.g., any configuration described herein). The configuration may be sent by (e.g., received from) a gNB or TRP. For example, the WTRU may receive configuration of one or more TRPs, one or more PL reference groups, and / or one or more SRI sets. A WTRU may (e.g., implicitly) determine an association between a RS set / group and a TRP. For example, if the WTRU is configured with two SRS resource sets, the WTRU may determine to transmit to TRP1 with SRS in the first resource set, and to TRP2 with SRS in the second resource set. The configuration may be sent via RRC signaling.

[0105] In the examples and embodiments described herein, TRP, PL reference group, SRI group, and SRI set may be used interchangeably. The terms set and group may be used interchangeably herein.

[0106] Feature(s) associated with CSI components are provided herein.

[0107] A WTRU may report a subset of CSI components. The CSI components may correspond to at least a CSI-RS resource indicator (CRI) (e.g., which indicates one CSI-RS resource out of a CSI-RSresource set), a SSB resource indicator (SSBRI) (e.g., which indicates one SSB out of a set of SSBs), an indication of a panel used for reception at the WTRU (e.g., such as a panel identity or group identity), measurements (e.g., such as L1-RSRP, L1-SINR) taken from SSB or CSI-RS (e.g. cri-RSRP, cri-SINR, ssb-Index-RSRP, ssb-Index-SINR), and / or other channel state information (e.g., such as at least rank indicator (RI), channel quality indicator (CQI), precoding matrix indicator (PMI), layer index (LI), and / or the like).

[0108] Feature(s) associated with property of a grant or assignment are provided herein.

[0109] A property of a grant or assignment may include one or more of the following: a frequency allocation; an aspect of time allocation, such as a duration; a priority; a modulation and coding scheme; a transport block size; a number of spatial layers; a number of transport blocks; a TCI state, CRI or SRI; a number of repetitions; whether the repetition scheme is Type A or Type B; whether the grant is a configured grant type 1, type 2 or a dynamic grant; whether the assignment is a dynamic assignment or a semi-persistent scheduling (configured) assignment; a configured grant index or a semi-persistent assignment index; a periodicity of a configured grant or assignment; a channel access priority class (CAPC); any parameter provided in a DCI, by MAC, or by RRC for the scheduling the grant or assignment; and / or the like.

[0110] An indication by DCI may include one or more of the following: an explicit indication by a DCI field or by RNTI used to mask CRC of the PDCCH; an implicit indication by a property (e.g., such as DCI format, DCI size, CORESET or search space, aggregation level, first resource element of the received DCI, for example, index of first control channel element, and / or the like). The mapping between the property and the value may be signaled by RRC or MAC.

[0111] As used herein, a signal may be interchangeably used with one or more of following: a sounding reference signal (SRS); channel state information (e.g., CSI reference signal (CSI-RS)); a demodulation reference signal (DM-RS); a phase tracking reference signal (PT-RS); a synchronization signal block (SSB); an / or the like.

[0112] As used herein, a channel may be interchangeably used with one or more of following: a physical downlink control channel (PDCCH); a physical downlink shared channel (PDSCH); a physical uplink control channel (PUCCH); a physical uplink shared channel (PUSCH);a physical random-access channel (PRACH); etc.

[0113] As used herein, downlink reception may be used interchangeably with receive (Rx or RX) occasion, PDCCH, PDSCH, SSB reception, etc. As used herein, uplink transmission may be used interchangeably with transmission (Tx or TX) occasion, PUCCH, PUSCH, PRACH, SRS transmission, etc. As used herein, RS may be interchangeably used with one or more of RS resource, RS resource set, RSport and RS port group, etc. As used herein, RS may be interchangeably used with one or more of SSB, CSI-RS, SRS and DM-RS, etc. As used herein, time instance may be interchangeably used with slot, symbol, subframe, etc.

[0114] Feature(s) associated with WTRU-assisted dynamic code book restriction are provided herein.

[0115] Feature(s) described herein may be used to reduce the complexity of PMI search and CSI feedback overhead for large antenna array systems that are configured with a large grid-of-beams (GoB).

[0116] The codebook subsets may be dynamically determined (e.g., based on a previously reported PMI). The WTRU may report a PMI for a first instance (e.g., from which the codebook subset for the consecutive report is determined). The WTRU may search and report PMIs from a restricted codebook subset that dynamically changes as a function of previous PMI. The size of the restriction may be based on a (e.g., preconfigured) threshold (e.g., as illustrated in FIG.2A).

[0117] The WTRU may receive a configuration of CSI reporting. The configuration may include a definition of the GoB and search space (e.g., which may be the GoB or part of the GoB). At a first time, the WTRU may send a first CSI report (e.g., associated with the search space and GoB) with a first beam indicated by a precoding matrix indicator. For example, the WTRU may report a CSI at time ^^0with the i-th beam indicated in the PMI (e.g., indicated by ^^^^( ^^0)). The first search space may be the whole GoB. The WTRU may include an indication in the CSI report at time ^^0that indicates application of the dynamic codebook restriction.

[0118] At a second time, the WTRU may determine a second search space based on the first beam and at least one threshold. For example, at time ^^1, the WTRU may determine a second search space and / or search space size (e.g., which is a part of GoB). For example, the WTRU may determine a second search space and / or search space size as a function of the previous CSI report (e.g., as a function of the beam indicated in the PMI of the previous CSI report) and configured thresholds (e.g., ∆1and ∆2).

[0119] The second search space may be smaller than the first search space and centered around the first beam. The threshold(s) may indicate at least one of a first distance and a second distance. The WTRU may determine the second search space based on the first beam and the at least one threshold by including, in the second search space, beams that are vertically located within the first distance from the first beam and horizontally located within the second distance from the first beam. The threshold(s) may include a set of search space dimensions. The WTRU may determine the set of search space dimensions based on one or more parameters and send an indication of the set of search space dimensions to the network entity. For example, the second search space may be determined to include the beams that are vertically + / - ∆1beams in the codebook from the location of ^^^^( ^^0). The second search space may bedetermined to include the beams that are horizontally + / - ∆2beams in the codebook from the location ^^^^( ^^0). In some examples, ∆1may be equal to ∆2(e.g., ∆= ∆1= ∆2), for example, as shown in FIG.2A.

[0120] The WTRU may select a second beam from the second search space. The WTRU may search the search space for a beam (e.g., a best beam or a beam that satisfies a criteria). The WTRU may determine the beam index relative to the second search space defined by + / - ∆1and + / - ∆2(e.g., where the beam index is indicated by ^^^^(^^1)). The WTRU may report (e.g., to the gNB) the selected beam. For example, the WTRU may send an indication of the second beam to a network entity. The WTRU may indicate the beam index ^^^^(^^1)and / or a previous beam index (e.g., ^^^^( ^^0)), and / or the index of the beam on which the second search space is centred.

[0121] At a third time, the WTRU may determine a third search space based on the second beam and the at least one threshold. The third search space may be smaller than the first search space and centered around the second beam. For example, at time ^^2, the WTRU may repeat the one or more of the actions for a search area centered at ^^^^(^^1). The WTRU may select a third beam from the third search space and send an indication of the third beam to the network entity.

[0122] The WTRU may stay centered on ^^^^( ^^0) for multiple TTIs. ∆1and ∆2may be configured per TRP. For example, the WTRU may determine a third search space based on the second beam and the at least one threshold. The third search space may be smaller than the first search space and centered around the first beam. For example, at time ^^2, the WTRU may repeat the one or more of the actions for a search area centered at ^^^^( ^^0). The WTRU may select a third beam from the third search space and send an indication of the third beam to the network entity.

[0123] The WTRU may reset (e.g., at time ^^0) after a configured ^^^^ ^^ ^^ ^^ ^^TTIs, or by WTRU / gNB indication.

[0124] FIGs.2A and 2B illustrates an example of a WTRU searching and reporting PMIs from a restricted codebook subset.

[0125] In examples (e.g., in new radio (NR)), the gNB may determine a precoder (e.g., the optimal precoder) based on CSI feedback of a codebook index. The WTRU may receive a configuration of a codebook. The codebook may be defined as a set of indices (PMIs). The PMIs may map (e.g., may each map) to a codeword (e.g., spatial filter or beam) from a set of codewords. A codeword (e.g., each codeword) may be applied across antennas at the gNB as a precoder to generate a beam. To derive a PMI (e.g., the optimal PMI), the WTRU may perform a search over indices (e.g., all indices) from the codebook. The WTRU may feedback the index (e.g., the optimal index) based on the WTRU determination. The search space (e.g., the set of indices to search from the codebook) may be preconfigured. The WTRU may receive the codebook search space through RRC.

[0126] The WTRU may dynamically determine the codebook search space from a subset of the RRC configured codebook search space. The WTRU may make a first determination of the PMI based on a first codebook search space. The WTRU may iteratively update the search space for the next reporting period(s). The WTRU may report a PMI within the dynamically changing search space.

[0127] A WTRU may be configured (e.g., by RRC, MAC-CE, or DCI) to determine and report a PMI (e.g., a wideband PMI or a sub-band PMI) by receiving a configuration of a RS (e.g., a CSI-RS resource configuration) with ^^1antenna ports in a first dimension and ^^2antenna ports in a second dimension. The WTRU may estimate the channel based on measurements on the RSs. The channel estimate may be used to determine the PMI. A WTRU may be configured (e.g., by RRC, MAC-CE, or DCI) with a codebook of beams, and with integer values (e.g., oversampling values O1 and O2) to oversample / increase the number of beams (e.g., oversample / increase the number of beams from ^^1^^2This may result in a grid-of-beams (GoB) with a larger number of beams (e.g., ^^1^^1^^2^^2number of beams). The GoB may represent the codebook from which the WTRU searches for a PMI.

[0128] The parameters for the dynamic search space update may be determined by the gNB. A WTRU may perform at least one of the following actions. At time ^^0(e.g., where ^^0maybe an indicative of a time when a WTRU reports a PMI for the first time, for example, a WTRU reporting a PMI for the first time after waking up from an idle mode, or a first PMI in a configured sequence of PMIs in this reporting method), the WTRU may search the entire search space (e.g., the search space with ^^1^^1^^2^^2beams in the GoB) and determine one or more beams (e.g., the ^^^^ℎbeam denoted as^^( ^^0) = 0,⋯ , ^^1^^1^^2^^2− 1). The WTRU may report it in a CSI report.

[0129] The bit-width of the indicator to indicate the determined beam(s) and / or PMI at ^^0, e.g.,may be a function of at least one of the following: the total number of determined beam(s); and / or the number of beams in the search space (e.g., the ^^1^^1^^2^^2number of beams). For example, at ^^0, the WTRU may report ^^ number of determined beams (e.g., ^^( ^^)^^( ^^0)( ^^0), where ^^ = 1,⋯ , ^^) using ^^1^^1^^2^^2number of bits. As another example, at ^^0, the WTRU may report the ^^ number of determined beams using ^^ ^^ ^^2( ^^1^^1^^2^^2^^ ) bits.

[0130] At ^^1, the WTRU may determine a second search space (e.g., that is a subset of the GoB). The second search space may be determined based on at least one of the following: as a function of the previous CSI report (e.g., as a function of the beam indicated in the PMI at time ^^0, e.g., ^^( ^^0)); as a function of preconfigured Δ values at ^^1(e.g., Δ1( ^^1), Δ2( ^^1), Δ3( ^^1), and / or Δ4( ^^1), which are described herein and define an area of the search space); and / or as a function of a beam index with the strongest coefficient level and / or amplitude level, in a PMI based on more than one beams and reported attime ^^0(e.g., ^^ ( ^^) ^^( ^^0), where ^^( ^^0) ∈ 0,⋯ , ^^1^^1^^2^^2− 1 and where ^^ is the index of the beam with the strongest coefficient level).

[0131] For a PMI determination with a (e.g., single) beam, the second search space at ^^1for the second PMI report may be determined based on the index of the beam reported at ^^0(e.g., the ^^(^^0)beam) and thevalues asBased on this, the WTRU may restrict its search space to the beams that are indexed relative to the previous beam report.

[0132] For a PMI determination with more than one beams, the second search space at ^^1may be determined based on the index of the beam with the strongest coefficient level at ^^ (e.g.,and Δ values at ^^1, e.g., Δ1( ^^1), Δ2( ^^1), Δ3( ^^1), ^^ ^^ ^^ Δ4( ^^1) values as follows:

[0133] At ^^1, a WTRU may determine beam(s) and / or a PMI based on the second search space (e.g., a PMI with more than one beams, for example, ^^^^^^( ^^1), where for example the strongest beam is denoted by ^^^^^^(^^^^1)= ^^y( ^^0)+Δ1( ^^1)). The WTRU may determine a PMI with one beam (e.g., a PMI denoted

[0134] A WTRU may report the determined PMI in a CSI report. The bit-width of the indicator to indicate the determined beam(s) and / or PMI may be a function of at least one of the following: the total number of determined beam(s); and / or the number of beams in the second search space (e.g., the(Δ1(^^1)Δ2(^^1)− 1)× (Δ3(^^1)Δ4(^^1)− 1) number of beams in the second search space).

[0135] The WTRU may report ^^ number of determined beams (e.g., ^^( ^^)^^( ^^1), using(Δ1(^^1)Δ2(^^1)− 1)× (Δ3(^^1)Δ4(^^1)− 1) number of bits. The WTRU may report the ^^ number of determined beams using

[0136] At ^^2, the WTRU may update the beam index(es) reported at ^^2(e.g., the beam index(es) ^^(^^2)and / or ^^( ^^2) becomes ^^( ^^2) = ^^( ^^1) + Δ1and / or ^^( ^^2) = ^^( ^^1) + Δ1). The WTRU mayreproduce / regenerate the second search space based on ^^( ^^2) and / or i( ^^2) and / or the Δ values (e.g., Δ1( ^^2), Δ2( ^^2), Δ3( ^^2), and / or Δ4( ^^2)). The WTRU may determine and report a PMI (e.g., ^^^^( ^^2)) based on the second search space at ^^2.

[0137] At ^^^^, the WTRU may perform at least one of the following actions. The WTRU may determine the center beam of the nth search space at ^^^^, based on the beam(s) reported at ^^^^−1, as described herein. For a PMI reporting with more than one beam (e.g., ^^^^^^), the center beam of the nth search space may be the strongest beam reported at ^^^^−1(e.g., the center beam of the nth search space at ^^^^, becomes ^^^^( ^^ ^^)= ^^^^^^(^^^^ ^^−1)). For a PMI reporting with one beam, the center beam of the nth search space may be the beam reported at ^^^^−1(e.g., the center beam of the nth search space at ^^^^becomes ^^^^( ^^ ^^)= ^^^^( ^^ ^^−1)). The WTRU may determine the nth search space based on the center beams (e.g., obtained as described herein) and based on the Δ values at ^^^^(e.g., Δ1( ^^^^), Δ2( ^^^^), Δ3( ^^^^), and / or Δ4( ^^^^)). The WTRU may determine and report a PMI from the nth search space.

[0138] The WTRU may (e.g., dynamically) change the bit-width of the indicator to indicate the PMI may at ^^^^based on one or more of the Δ values.

[0139] Feature(s) associated with determining the nth search space are provided herein.

[0140] At ^^^^, the WTRU may determine the nth search space based on the Δ value(s) at ^^^^(e.g., Δ1( ^^^^), Δ2( ^^^^), Δ3( ^^^^) and / or Δ4( ^^^^)) and the index of the beam(s) reported in the PMI at ^^^^−1(e.g., ^^( ^^^^−1)). If the defined / configured Δ values are such that the resulting nth search space results in violation of the boundary of the GoB with ^^1^^1^^2^^2beams (e.g.,+ Δ1(^^^^)> ^^1^^1), the WTRU may perform at least one of the following. The WTRU may adjust the Δ value(s) so that the boundary of the GoB is not violated (e.g., a WTRU adjusts Δ1(^^^^)so that ^^(^^^^−1)+ Δ1(^^^^)≤ ^^1^^1). The WTRU may report the adjusted Δ values with a higher priority in a CSI report (e.g., in part 1 of a CSI report). The WTRU may request the gNB for reconfiguration of the Δ values by sending a flag. The WTRU may request a change of the PMI reporting procedure by sending an indication to the gNB. At least one of the following may apply: requests gNB to configure the PMI reporting based on a GoB with ^^1^^1^^2^^2beams for all times; requests gNB to configure the PMI reporting based on a GoB with ^^1^^1^^2^^2beams at ^^^^+1and PMI reporting based on a second search space (e.g., as discussed herein) starting at ^^^^+2.

[0141] Feature(s) associated with reporting more than one beam are provided herein.

[0142] A WTRU may be configured (e.g., by RRC, MAC-CS and / or DCI) to report more than one beam (e.g., report K beams for sub-band beam selection; report ^^ beams for one or more layers; and / or the like.

[0143] Feature(s) associated with sub-band beam selection are provided herein. A WTRU may report more than one beams for sub-band beam selection. The WTRU may report ^^ number of beams and for asub-band (e.g., each sub-band). The WTRU may report one out of the K number of beams. At ^^0, the WTRU may determine (and report) K beams out of the GoB with ^^1^^1^^2^^2beams. At ^^0, the WTRU may determine (and report) one or more beams for one or more sub-bands out of the K determined beams.

[0144] The center beam of the second search space at ^^1may be chosen based on at least one of the following: the beam reported at ^^0for a sub-band with a given index (e.g., a sub-band with the lowest index); the beam reported at ^^0for a sub-band with the highest CQI; and / or the like.

[0145] Feature(s) associated with multiple beams for multiple layers are provided herein. The WTRU may be configured (e.g., by RRC, MAC-CE, and / or DCI) to report more than one beam for more than one layer. At ^^0, the WTRU may determine and report one or more beams for one or more layers. The chosen set of beams may be orthogonal to each other. The chosen beams may be determined based on the GoB with ^^1^^1^^2^^2beams. At ^^1, the WTRU may determine the center beam of the second search space based on at least one of the following: the beam reported at ^^0for a layer with a given index (e.g., a layer with the lowest index); the beam reported at ^^0for a layer with a specific traffic type and / or MCS (e.g., a layer with the URLLC traffic and / or a layer the highest MCS, respectively); and / or the like.

[0146] At ^^^^, a WTRU may determine a first beam within the nth search space and a second beam outside the nth search space. The first beam maybe orthogonal to the second beam. One or more beams may be orthogonal to the first beam reported at ^^^^. A WTRU may use an indicator to indicate one or more of the orthogonal beams at ^^^^.

[0147] At ^^^^, the WTRU may divide the GoB into more than one second search spaces. For example, the WTRU may (e.g., at a third time) determine a third search space and a fourth search space. The third search space may be smaller than the first search space and may be centered around the second beam. The fourth search space may be smaller than the first search space and may be centered around the third beam. The center beams for one or more nth search spaces may be determined based on one or more beams reported at ^^^^−1. The one or more nth search spaces may use the same or different Δ values for one or more of the nth search spaces.

[0148] The WTRU may determine the minimum WTRU processing time based on the second search space (e.g., as a function of ∆1and ∆2values). In this case, as ∆1and ∆2increase, the search space may increase. The minimum WTRU processing time to measure the CSI-RS symbols may increase. The time for reporting the measured CSI-RS subsets to gNB may increase. The WTRU may report a PMI for the first-time instance from which the codebook subset for the consecutive report is determined.

[0149] The Δ values may be used by the WTRU to determine the search space subset as a function of the search space, and a PMI reported in a previous time instance. The Δ values may bedefined / determined / configured for the directions (e.g., each of the four directions) of the GoB (e.g., Δ1, Δ2, Δ3, and / or Δ4). The Δ values may be defined per dimension of the GoB (e.g., Δ1= Δ2and Δ3= Δ4). A (e.g., single) Δ values may be defined / determined / configured (e.g., Δ1= Δ2= Δ3= Δ4). The Δ values may be defined as a fixed value (e.g., the same value is used all the time). The Δ values may be configured by gNB (e.g., by RRC, MAC-CE and / or DCI) for one or more instances of the PMI reporting.

[0150] Example WTRU-determined search space subset parameters are described herein. A WTRU may determine the Δ value(s) at one or more instances of the PMI determination and reporting (e.g., a WTRU determines Δ1( ^^^^), Δ2( ^^^^), Δ3( ^^^^) and / or Δ4( ^^^^) when determining the PMI at ^^^^). The WTRU may be configured to report a CSI in two parts (e.g., part 1 and 2) sent in different time slots. The WTRU may report the determined Δ value(s) that define the PMI search space with a higher priority (e.g., in part 1 of a CSI report). The WTRU may report the PMI as a function of the PMI search space (e.g., in part 2 of a CSI report). The WTRU may dynamically change the bit-width of the indicator for reporting PMI at ^^^^(e.g., based on the determined Δ values).

[0151] Search space subset parameters may be implicitly determined. The Δ value(s) (e.g., ∆1and ∆2) maybe determined by the WTRU based on at least one of the following: WTRU processing capability (e.g., WTRU determines the Δ values as a function of its ability to determine the CSI, for example, as a function of the number of CPUs to determine the CSI); a CSI reference slot; MCS / number of layers; a traffic type; a codebook type; a number of antenna ports; mobility (e.g., doppler); a grant type (e.g., configured or dynamic); a number of TRPs for CJT; a number of maximum ranks per TRP; and / or the like.

[0152] The WTRU may receive an association between a TCI state and codebook subsets. The association may be configured by linking a (e.g., one) TCI state to a subset from the GoB. A subset (e.g., each subset) may correspond to a set of beams. In a first example, a TCI state (e.g., each TCI state) may map to a (e.g., one) subset. In a second example, a TCI state (e.g., each TCI state) may be configured with multiple QCL type D source RS. In this case, a source RS (e.g., each source RS) may be associated with a different subset. The WTRU may determine which subset to use (e.g., as a function of which source RS is activated in the TCI state).

[0153] The WTRU may receive a configuration of multiple codebook subsets. A subset (e.g., each subset) may be associated with a threshold. The threshold may be based on signal quality (e.g., RSRP), or WTRU location (e.g., distance in meter from the gNB). The WTRU may select the codebook search space subset as a function of its signal quality or location measured above the threshold.

[0154] The WTRU may reset (e.g., reset the procedure described herein) if there is a misdetection of CSI.

[0155] If the WTRU reports CSI, and the gNB misses detection of the CSI, the follow up CSI may be interpreted incorrectly (e.g., since the PMI at each time is relative to the search space from a previous report). The search space in the restricted codebook may be centered with the inaccurate beam. To overcome this problem, the WTRU may report an index that maps to the selected codebook subset search space ID to the gNB. The subset ID may be transmitted with a preconfigured periodicity. The WTRU may include the subset ID in ever nth CSI report. The WTRU may define the prioritization rule for dropping beam index instead of code book subset ID. The WTRU may report the sub beam index if (e.g., only if) there has been a change in the subset.

[0156] The gNB may indicate to the WTRU to reset the search space or to use the same search space as used for a previous reporting (e.g., if the gNB detects a number of NACKs in HARQ above a threshold, or detects an error in the CSI report). The WTRU may receive a MAC-CE configured with a mapping of activation commands to codebook search space subsets. WTRU may modify the codebook search space subset parameters as a function of the MAC-CE activation / deactivation commands.

[0157] The WTRU may be configured with a timer. The WTRU may reset the search space when the timer expires. At expiry of the timer, the WTRU may repeat the actions described herein for dynamic codebook restriction (e.g., from the beginning starting from the initially RRC configured search space).

[0158] The WTRU may determine co-phasing with partitioned CSI resources. The WTRU may determine co-phasing information for large antenna array systems configured with high number of CSI ports.

[0159] If CSI-RS resources (e.g., all CSI-RS resources) cannot be mapped within a same slot, the WTRU may partition the CSI-RS resources between subsets. The WTRU may use these partitions to determine the co-phasing information.

[0160] The WTRU may receive information that indicates a first channel state information reference signal (CSI-RS) resource set associated with a first set of CSI-RS ports and a second CSI-RS resource set associated with a second set of CSI-RS ports. The first set of CSI-RS ports may include a first plurality of ports mapped to the first CSI-RS resource set. The second set of CSI-RS ports may include a second plurality of ports mapped to the second CSI-RS resource set. The WTRU may receive a first CSI-RS resource configuration (e.g., with a mapping of M CSI-RS ports to N subsets). The mapping may overlap between adjacent subsets (e.g., some of the ports from subset n and n+1 are the same). The mapping may be based on non-overlapping subsets (e.g., N=2 polarizations). In this case, the WTRU may receive a second CSI-RS resource configuration (e.g., where each port is associated to the first or second subset, for example, polarization, of CSI-RS resources from the first CSI resource configuration).

[0161] The WTRU may receive CSI-RS in CSI-RS resources in the first CSI-RS resource set and / or second CSI-RS resource set (e.g., that are transmitted on up to N subsets of ports in up to N different slots). The sequence of transmitted subsets may be according to a configured time-based pattern (e.g., that identifies which subset(s) of ports is / are used in which symbols and / or slots when CSI-RS is transmitted in the CSI-RS resources in the first and / or second CSI-RS resource set).

[0162] The WTRU may determine (e.g., or take) measurements based on the received CSI-RS. The WTRU may determine a first measurement based on the CSI-RS received in the first CSI-RS resource set, and a second measurement based on the CSI-RS received in the second CSI-RS resource set.

[0163] The WTRU may determine a PMI for the N subsets (e.g., each of the N subsets) based on the measurements. For example, the WTRU may determine a first PMI associated with the first CSI-RS resource set based on the first measurement, and a second PMI associated with the second CSI-RS resource set based on the second measurement.

[0164] If overlapped subset resources (e.g., at least one CSI-RS resource in the first CSI-RS resource set is in the second CSI-RS resource set) are considered or used, the WTRU may measure the co-phasing between ports associated to adjacent subsets. In this case, the CSI report may indicate a quantized co- phasing measurement between the first CSI-RS resource set and the second CSI-RS resource set. If non- overlapped subset resources (e.g., the first CSI-RS resource set and the second CSI-RS resource set are disjoint sets) are considered or used, the WTRU may measure the co-phasing across ports associated to different subsets on the second CSI-RS resource configuration. In this case, the CSI report may indicate measured co-phasing across the first set of CSI-RS ports and the second set of CSI-RS ports.

[0165] The WTRU may send (e.g., to a network entity) a CSI report that indicates the first PMI and the second PMI. For example, the WTRU may report one or more of the following (e.g., in a single CSI report): the N determined precoders; the N-1 quantized co-phasing measurements between adjacent subsets (e.g., if overlapped subset resources are considered or used); and / or the measured co-phasing across ports associated to different subsets of ports indicated by W^^ ^^− ^^ℎ ^^ ^^ ^^ ^^ ^^(e.g., if non-overlapped subset resources are considered or used).

[0166] Resources may be overlapped or non-overlapped. In the case of overlapped resources, a gNB may partition the configured CSI ports (e.g., 64 ports), into multiple subsets where each subset supports a smaller number of CSI ports (e.g., 32 ports), as described with respect to FIG.3. The WTRU may be configured with multiple subsets. One or more CSI ports may be mapped to more than one subset (e.g., there is an overlap between subsets). For example, for the case of CSI with 64 ports, four subsets may be considered: subset 1: ports 1-32; subset 2: ports 17-48; subset 3: ports 33-56; and subset 4: ports 49-64. In this case, 16 ports are common between every two subsets.

[0167] The CSI-RS ports may be divided into N subsets (e.g., where there are common ports between each two adjacent subsets).

[0168] The WTRU may receive the CSI-RS subsets. The WTRU may determine the co-phasing matrix between two adjacent subsets (e.g., each two adjacent subsets). In this case, N-1 co-phasing matrices may be determined.

[0169] The WTRU may report PMI for a subset (e.g., each subset). The WTRU may report the co- phasing matrices to the gNB (e.g., to assist in channel estimation and precoding determination).

[0170] The overlapping ports may vary for a measurement event (e.g., each measurement event) over the 64 ports. For example, the port assignments may rotate based on a pre-configured or pseudo-random pattern. Port rotation may be based on a system operational parameter or information (e.g., slot number, bandwidth part ID, etc.).

[0171] CSI-RS resource partitioning may be based on polarization. The WTRU may determine the first CSI-RS resource set based on a first polarization of CSI-RS ports in the first set of CSI-RS ports. The WTRU may determine the second CSI-RS resource set based on a second polarization (e.g., different from the first polarization) of CSI-RS ports in the second set of CSI-RS ports. One or more CSI-RS resources may be aggregated, combined, and / or used for a measurement of a larger number of antenna ports. For example, the WTRU may aggregate a second CSI-RS resource set and a third CSI-RS resource set to generate a combined CSI-RS resource set. The WTRU may determine the second measurement based on the CSI-RS received in the combined CSI-RS resource set.

[0172] In an example, N1 antenna ports CSI-RS resource and N2 antenna ports CSI-RS resource may be aggregated, combined, and / or used for a measurement of MTantenna ports MIMO channel (e.g., wherein MT= N1+ N2or ^^^^= ^^1× ^^2). In another example, two N1antenna ports CSI-RS resource and one N2antenna ports CSI-RS resource may be aggregated, combined, and / or used for a measurement of MT antenna ports MIMO channel (e.g., ^^^^= 2 ^^1+ ^^2).

[0173] As used herein, the MT antenna port’s CSI-RS resource that is based on aggregation of one or more smaller antenna ports CSI-RS resources may be referred to as composite CSI-RS resource, aggregated CSI-RS resource, concatenated CSI-RS resource, or combined CSI-RS resource. The one or more CSI-RS resources aggregated, combined, or concatenated for the composite CSI-RS resource may be referred to as component CSI-RS resource.

[0174] The component CSI-RS resources may be multiplexed in time and / or frequency resources. If component CSI-RS resources are multiplexed in frequency resources, the component CSI-RS resources may be located in a different subset of RBs in a slot. If component CSI-RS resources are multiplexed in time resources, the component CSI-RS resources may be located within a certain time window (e.g., TW).The time window may be determined as a function of at least one of WTRU speed, Doppler frequency, channel coherence time, and / or time domain channel properties (TDCP).

[0175] Component CSI-RS resources may have an association with antenna polarization.

[0176] One or more component CSI-RS resources for a composite CSI-RS resource may be associated with a specific polarization of antenna ports. For example, if a gNB uses polarized antennas (e.g., v-pol and h-pol), a first component CSI-RS resources may be associated with a first polarization (e.g., v-pol) and a second component CSI-RS resources may be associated with a second polarization (e.g., h-pol). One or more of following may apply. Associated polarization information may be configured with a component CSI- RS resource. For example, a component CSI-RS resource configuration may include NZP-CSI-RS resource identity, number of antenna ports, and its associated polarization (e.g., v-pol or h-pol). An associated polarization for a component CSI-RS resource may be determined based on NZP-CSI-RS resource identity. If component CSI-RS resources are multiplexed in time domain (e.g., in different time resources including slot, subframe, and / or symbol), additional component CSI-RS resources that represent polarized antenna ports (e.g., two ports CSI-RS in which a first antenna port is associated with v-pol and a second antenna port is associated with h-pol) may be used (e.g., so that a WTRU may estimate co-phasing information across polarized antenna ports).

[0177] One or more (e.g., two) component CSI-RS resources for a composite CSI-RS resource may be used. A first component CSI-RS resource may be associated with antenna ports with the same polarization (e.g., both v-pol and h-pol) and a second component CSI-RS resource may be associated with polarized antenna ports (e.g., two ports CSI-RS resource where a first port associated with v-pol and a second port ^^ associated with h-pol). If MTis N, a first component CSI-RS resource may be 2 ports CSI-RS resource and a second component CSI-RS resource may be 2 ports CSI-RS resource.

[0178] Feature(s) associated with component CSI-RS resource association across different slots (e.g., including sampled CSI-RS transmissions) are provided herein.

[0179] One or more component CSI-RS resources for a composite CSI-RS resource may be associated in a time-domain transmission pattern. A WTRU may be configured with or indicated the time-domain transmission pattern via RRC, MAC-CE, and / or DCI. The one or more component CSI-RS resources may include a first component CSI-RS resource and a second component CSI-RS resource (e.g., and may include a third or more component CSI-RS resources). One or more of following may apply. The time- domain transmission pattern may include one or more parameters based on at least one of periodicity, time-domain offset(s), slot index(es), and / or symbol index(es).

[0180] The WTRU may determine (e.g., based on a time-based recursive pattern) which one or more CSI-RS resource sets (e.g., of the first CSI-RS resource set and the second CSI-RS resource set) in whichto receive the CSI-RS. Based on the periodicity and / or time-domain offset(s), the WTRU may determine on which slot / symbol the first component CSI-RS resource is transmitted and / or on which slot / symbol the second component CSI-RS resource is transmitted. The first component CSI-RS resource and the second component CSI-RS resource may be transmitted in a periodic way. Transmissions of the second component CSI-RS resource may be shifted in time by the time-domain offset compared to transmissions of the first component CSI-RS resource.

[0181] Based on the slot index(es) and / or symbol index(es), the WTRU may determine on which slot / symbol the first component CSI-RS resource is transmitted (e.g., in an irregular pattern in time by the slot / symbol index(es)) and / or on which slot / symbol the second component CSI-RS resource is transmitted (e.g., in an irregular pattern in time by the slot / symbol index(es)).

[0182] A WTRU may perform measurement(s) and reporting. The WTRU may receive configuration information indicating the number of antenna ports of the composite CSI-RS resource (e.g., MT) for measurement. The WTRU may receive configuration information indicating the number of antenna ports of the first component CSI-RS resource (e.g., N1). The WTRU may receive configuration information indicating the number of antenna ports of the second component CSI-RS resource (e.g., N2). MTmay be equal to (or less than) N1+ N2. If MTis less than N1+ N2, the WTRU may receive an additional configuration or indication on Nc (e.g., Nc = N1 + N2 - MT) with which the WTRU is configured to perform an inter-CSI measurement (e.g., deriving co-phasing coefficient(s)) based on both the first and second component CSI-RS resources. The Nc antenna ports may be included in a third component CSI-RS resource (e.g., for the purpose of the inter-CSI measurement) that may be configured to the WTRU.

[0183] The WTRU may receive one or more interference measurement resources (e.g., CSI-IM resource(s)) for interference measurement. Based on the configured MT (e.g., at time T1), the WTRU may determine a first channel measurement over the MT ports (e.g., MT=64). The WTRU may determine (and report) one or more PMIs (e.g., via PMI reporting) based on the first channel measurement. The one or more PMIs may represent a MT-by-r (precoding) matrix. r may be a rank reported by the WTRU via RI reporting. The WTRU may determine (and report) a CQI and / or a L1-SINR based on the first channel measurement and a first interference measurement (e.g., based on the CSI-IM resource(s)).

[0184] A WTRU may sample a CSI-RS transmission. The WTRU may receive an indication or configuration informing the WTRU of performing a second channel measurement over the MT antenna ports, upon (e.g., after) measuring a subset (e.g., the N1or the N2) of the MTantenna ports in a given measurement time (e.g., at time T2).

[0185] At time T2, the WTRU may measure the first component CSI-RS resource (e.g., with N1 ports) based on the time-domain transmission pattern (e.g., where the second component CSI-RS resource is not transmitted in T2 based on the time-domain transmission pattern). In response to such a partial channelmeasurement (e.g., based on the sampled CSI-RS transmission where only N1ports are transmitted via the first component CSI-RS resource), the WTRU may determine a second channel measurement over the MTports (e.g., MT=64). For example, the WTRU may determine the second channel measurement by applying interpolation and / or extrapolation of the (e.g., newly) measured N1ports over the (e.g., previously or most-recently) measured MT ports (e.g., the first channel measurement). The WTRU may determine (and report) one or more PMIs (e.g., via PMI reporting representing a MT-by-r (precoding) matrix) based on the second channel measurement, RI, and / or CQI (and / or L1-SINR) based on a second interference measurement (e.g., based on configured or indicated CSI-IM resource(s)).

[0186] At time T3, the WTRU may measure the second component CSI-RS resource (with N2ports) based on the time-domain transmission pattern (e.g., where the first component CSI-RS resource is not transmitted in T3 based on the time-domain transmission pattern). In response to such a partial channel measurement (e.g., based on the sampled CSI-RS transmission where only N2ports are transmitted via the second component CSI-RS resource), the WTRU may determine a third channel measurement over the MT ports (e.g., MT=64). For example, the WTRU may determine the third channel measurement by applying interpolation and / or extrapolation of the (e.g., newly) measured N2ports over the (e.g., previously or most-recently) measured MTports (e.g., the first channel measurement or the second channel measurement). The WTRU may determine (and report) one or more PMIs (e.g., via PMI reporting representing a MT-by-r (precoding) matrix) based on the third channel measurement, RI, and / or CQI (and / or L1-SINR) based on a third interference measurement (e.g., based on configured or indicated CSI- IM resource(s)).

[0187] The sampled CSI-RS transmission (e.g., such a partial channel measurement) may reduce CSI- RS transmission overhead (e.g., because the gNB may only transmit a subset of CSI-RS ports in a given time, for example, based on the time-domain transmission pattern, which may save the CSI-RS transmission resource overhead). If, in the given time, the WTRU measures (e.g., only measures) a subset of ports (e.g., N1 or N2 ports), the WTRU may measure the whole dimension of a channel (e.g., over the MT ports) based on applying the interpolation and / or extrapolation of the (e.g., newly) measured subset of ports over the (e.g., previously or most-recently) measured MTports. This may improve the CSI reporting performance (e.g., accuracy) by reporting a corresponding channel quality metric (e.g., the CQI and / or L1- SINR) derived based on assuming the whole dimension of a channel (e.g., over the MT ports), for example, not based on assuming a partial dimension of the channel (e.g., over N1or N2ports even though this is actually measured in the given time).

[0188] Component CSI-RS resource(s) may be associated with one or more component precoding matrices.

[0189] A precoder may be constructed with one or more component precoders. For example, a precoder ( ^^) may be constructed with ^^ = ^^1^^^^^^2(e.g., where ^^ may be referred to as precoder, composite precoder, codebook, or composite codebook and ^^^^, ^^ = 1,2, ^^ may be referred to as component precoder or component codebook). A WTRU may report a preferred precoder information (e.g., PMI) together with other CSI information (e.g., CQI, RI, L1-RSRP) based on the measurement of composite CSI- RS resource.

[0190] The WTRU may report a precoder information as a set of component precoder information. For example, the WTRU may report preferred component precoder information ^^^^, ^^ = 1,2, ^^. The gNB may combine the reported information to construct the precoder ^^. The component precoder information may be reported together or reported at different times. If the WTRU reports component precoder information, the priority level of a component precoder (e.g., each component precoder) may be different. Based on the priority level of each component precoder, the WTRU may drop a lower priority component precoder information (e.g., if uplink resource for CSI reporting is limited or uplink resource conflict occurs).

[0191] One or more component CSI-RS resources may be associated with one or more component precoders for CSI reporting. For example, three component CSI-RS resources may be used for MT ports CSI-RS resource. The MTports CSI-RS resource may be used for a CSI reporting with a codebook ^^ = ^^1^^^^^^2. In this case, a first component CSI-RS resource may be used to determine ^^1; a second component CSI-RS resource may be used to determine ^^^^; and a third component CSI-RS resource may be used to determine ^^2, etc. In another example, two component CSI-RS resources may be used for a CSI reporting with a codebook ^^ = ^^1^^^^^^2. In this case, a first component CSI-RS resource may be used to determine ^^1^^^^; and a second component CSI-RS resource may be used to determine ^^2.

[0192] A WTRU may report a subset of component precoders / codebooks based on availability of the measurement resources. For example, if a subset (e.g., only a subset) of component CSI-RS resources is available within a certain time window for a CSI reporting, the WTRU may report one or more component precoders / codebooks associated with component CSI-RS resources available (e.g., within the time window). The rest of component precoder / codebook may be assumed based on the latest reporting. One or more component CSI-RS resources may be associated with a single component precoder / codebooks. One or more component precoders / codebooks may be associated with a (e.g., single) component CSI-RS resources.

[0193] In the case of non-overlapped resources, (e.g., using the same CSI resources mapped to two polarizations), a subset (e.g., each subset) may be associated with a first and a second polarization. For example, in the case of CSI with 64 ports, using the same CSI-RS resources, the first and the second subset of 32 ports may be mapped on a first and a second polarizations.

[0194] A gNB may partition the configured CSI ports (e.g., 64 ports) into to multiple subsets supporting a smaller number of CSI ports (e.g., 32 ports). A subset (e.g., each subset) may be associated to a different polarization (e.g., to a first and a second polarization), as shown in FIG.4.

[0195] Using the same CSI resources, a subset (e.g., each subset) may be associated with a first and a second polarization. For example, in the case of CSI with 64 ports, using the same CSI-RS resources, the first and the second subset of 32 ports may be mapped on a first and a second polarizations. The WTRU may receive the first and second subsets. The WTRU may determine the precoding matrixes for the first and second subsets (e.g., W^^ ^^ ^^−1and W^^ ^^ ^^−2, respectively).

[0196] The two subsets may have the cross polarizations that have not yet been calculated by the WTRU (e.g., due to the separate reception of subsets indicatedTwo-port CSI may be transmitted on a (e.g., single) CSI-RS resource by using a (e.g., one) pair of polarizations. A WTRU may determine and report the co-phasing information for downlink PMI (e.g., PMI type I and / or type II codebooks). The WTRU may receive a two-port CSI on a (e.g., single) CSI-RS resource. The WTRU may determine and report the co-phasing to gNB (e.g., along withand W^^ ^^ ^^−2).

[0197] The precoder matrix (e.g., the overall precoder matrix W^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^) may include two block precoders. The first may be applied on a first polarization. The second may be applied on the second polarization.where W^^ ^^ ^^−1refers to the first set of CSI-resources; W^^ ^^ ^^−2refers to the second set of CSI-resources; W^^ ^^− ^^ℎ ^^ ^^ ^^ ^^ ^^refers to {First set of CSI-resources, Second set of CSI-resources}. The WTRU may determine and report W^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^to the gNB.

[0198] A WTRU may perform partial CSI reporting. The WTRU may receive an implicit CSI port indication for partial reporting.

[0199] The number of CSI ports may be increased (e.g., without direct scaling of the CSI-RS resources and / or procedures). The WTRU may associate a TCI state to a subset of ports (e.g., each subset of ports). A subset of ports may be indicated by indicating its associated TCI state(s) (e.g., in a triggering DCI, as illustrated in FIG.5).

[0200] The WTRU may receive a CSI configuration of a CSI-RS resource with N CSI ports (e.g., where M subsets of the N CSI-RS ports are mapped to a same set of CSI-RS resource elements (REs) in M different transmission slots). The CSI-RS resource configuration may include a linkage of CSI-RS ports to CSI-RS RE’s in a subset (e.g., each subset). The configuration may include the pattern of CSI-RS ports mapping in time and frequency (e.g., per subset). For example, the received configuration may map N=128CSI-RS ports over M=4 transmission slots. In this case, in a transmission slot (e.g., in each transmission slot), 32 ports may be mapped to a same set of CSI-RS RE’s.

[0201] The WTRU may receive TCI association information that maps the ports (e.g., each of the N ports) to a TCI state (e.g., one of L configured TCI states (QCL)).

[0202] The WTRU may receive configuration information that indicates a mapping between TCI states and sets of CSI-RS ports. The WTRU may determine the set of CSI-RS ports based on the indication of the TCI state and the mapping. For example, the received configuration may associate the ports (e.g., each of N=128 ports) to one of L=8 TCI states. For example, ports 1-12 and ports 13-32 from the first subset (e.g., slot) may be associated to TCI1 and TCI2, respectively, and, ports 65-96 from the third subset (e.g., slot) may be associated to TCI6.

[0203] The WTRU may receive (e.g., from a network entity) a DCI to trigger an aperiodic CSI report. The DCI may include an indication for selecting the CSI-RS resource, one or more of L TCI states for CSI reporting, a physical uplink shared channel (PUSCH) resource, and / or an indication to perform aperiodic CSI reporting.

[0204] The WTRU may determine a set of CSI-RS ports based on the indication of the TCI state. The WTRU may determine a transmission slot associated with the set of CSI-RS ports. Based on the determined ports associated to the indicated TCI states, the WTRU may determine CSI-RS REs for CSI measurement in a transmission slot (e.g., each transmission slot). For example, the received indication may point to the ports associated to TCI1, TCI2, and TCI6 that are mapped to CSI-RS REs of the CSI-RS resource in the first and third subsets (e.g., slots). The WTRU may send a CSI report to the network entity using the set of CSI-RS resource elements. For example, the WTRU may measure and report CSI for (e.g., only for) the indicated CSI-RS REs.

[0205] The WTRU may determine that a capacity of the set of CSI-RS resource elements is insufficient to send the CSI report. If the capacity of the indicated PUSCH resources is not large enough to report all the CSI, the WTRU may select a subset of CSI for reporting (e.g., according to one or more of the following rules). The WTRU may determine a respective measured channel quality metric for each CSI in the plurality of CSI. For example, the WTRU may select the CSI associated to an indicated TCI for reporting, if its measured channel quality metric meets (e.g., is above / greater than) a configured threshold (e.g., rank>4, CQI>12, etc.). The WTRU may select the CSI associated to an indicated TCI for reporting, if its measured channel quality metric have exhibited the largest variation over a configured time window. The WTRU may select the CSI associated to an indicated TCI for reporting, if its last report is the oldest report among other indicated TCI states for reporting. For example, the WTRU may determine a respectivereporting age for each CSI in the plurality of CSI and select, as the subset of CSI, a CSI associated with an oldest reporting age.

[0206] The WTRU may report CSI of the indicated TCI states using the indicated PUSCH resources. If the WTRU selects CSI to report, the WTRU may include the indices of the TCI states for which the associated CSI is reported.

[0207] The WTRU may receive a CSI configuration to support N CSI ports (e.g., where the N CSI ports are spread over more than one transmission slot). The WTRU may receive a CSI configuration of a CSI-RS resource with N CSI ports (e.g., where M subsets of the N CSI-RS ports may be mapped to a same or different sets of CSI-RS REs in M different slots). For example, as shown in FIG.5, the WTRU may be configured with 128 CSI-RS ports where in each slot, 32 CSI ports are mapped to a set of CSI REs.

[0208] FIG.5 illustrates indicating a subset of ports based on its associated TCI states in the triggering DCI.

[0209] The CSI-RS resource configuration may include a linkage of CSI-RS ports to CSI-RS REs in each subset. The configuration may include the pattern of CSI-RS ports mapping in time and frequency (e.g., per subset). For example, based on the first CSI-RS resource set, the second CSI-RS resource set, and a pattern for assigning ports to CSI-RS resource sets, the WTRU may determine a third CSI-RS resource set associated with a third set of CSI-RS ports and a fourth CSI-RS resource set associated with a fourth set of CSI-RS ports. The WTRU may determine measurements and PMIs associated with the third and fourth CSI-RS resource sets. The WTRU may report the measurements and / or the PMIs.

[0210] The WTRU may receive TCI association information that maps the N ports (e.g., each of the N ports) to a TCI state (e.g., one of L configured TCI states (QCL)). For example, if the WTRU is configured with N=128 CSI ports, the received configuration may associate each of N=128 configured ports to a TCI state (e.g., one of L=8 TCI states). For example, ports 1-12 and ports 13-32 from the first subset (slot) may be associated with TCI1 and TCI2, respectively, and, ports 65-96 from the third subset (slot) may be associated with TCI6.

[0211] The WTRU may receive a dynamic indication (e.g., a DCI, to trigger an aperiodic CSI report). The indication may include an information element to indicate selecting the CSI-RS resource and one or more of L TCI states for CSI reporting. The dynamic indication may indicate a PUSCH resource for transmission of the CSI report.

[0212] The WTRU may determine CSI-RS REs for CSI measurement in a slot (e.g., each slot) based on the determined ports associated to the indicated TCI states. For example, the received indication may point to the ports associated to TCI1, TCI2 and TCI6 that are mapped to CSI-RS REs of the CSI-RS resource inthe first and third subsets (slots). The WTRU may measure and report CSI for (e.g., only for) the indicated CSI-RS REs.

[0213] The WTRU may report (e.g., be required to report) CSI content that is larger than the allocated PUSCH resource. The WTRU may reduce the CSI payload size. For example, if the capacity of indicated PUSCH resources is not large enough to report all configured CSI quantity for all CSI ports, the WTRU may select the CSI for reporting according to one or more of the following rules.

[0214] The WTRU may be configured with one or more thresholds. The WTRU may select the CSI associated to an indicated TCI for reporting, if its measured channel quality metric meets a configured threshold. For example, the WTRU may report (e.g., only report) the CSI of the subset that the rank or CQI associated to the resources to that subset (e.g., rank>4, CQI>12, etc.).

[0215] The WTRU may be configured with a counter or a time window. The WTRU may select the CSI associated to an indicated TCI for reporting, if its measured channel quantity has exhibited the largest variation over the configured time window. For example, the WTRU may report the CSI of the subset that its associated CSI ports are most “stale.”

[0216] The WTRU may select the CSI associated to an indicated TCI for reporting, if its last report is the oldest report among other indicated TCI states for reporting. The WTRU may report CSI of the indicated TCI states using the indicated PUSCH resources. If the WTRU performs CSI selection, the WTRU may include the indices of the TCI states which their CSI are reported.

[0217] The WTRU may receive an explicit CSI port indication for partial reporting.

[0218] The WTRU may receive a CSI configuration to support N CSI ports (e.g., where the N CSI ports are spread over more than one transmission slot). The WTRU may receive a CSI configuration of a CSI-RS resource with N CSI ports (e.g., where M subsets of the N CSI-RS ports may be mapped to a same or different sets of CSI-RS RE’s in M different slots).

[0219] The WTRU may receive a dynamic indication (e.g., a DCI) to explicitly indicate the subset with associated CSI ports that are to be measured and reported. The DCI may be used to indicate which CSI- RS port subset is to be utilized at any given time by the WTRU. The DCI may indicate the uplink resources to be used for the CSI report.

[0220] Additional bits in the DCI may be used to indicate the CSI-RS port subset. An extended DCI format may be introduced to accommodate this (e.g., with 128 CSI-RS ports divided into 8 subsets, three additional bits may be used).

[0221] The gNB may dynamically configure the CSI-RS port subset (e.g., based on channel conditions, interference, network load, etc.). The corresponding index of the CSI-RS port subset may be sent throughthe DCI trigger to the WTRU. The WTRU may provide the gNB with feedback regarding the CSI-RS port subsets (e.g., indicating a preferred user-specific CSI-RS port subset or combination of subsets, ranking and signaling the performance of the different CSI-RS port subsets, etc.). The feedback may be based on historical and / or current data measurements.

[0222] By utilizing the CSI-RS port subset in the DCI, the system may reduce the associated overhead with transmitting CSI-RS from all ports in any given time.

[0223] The WTRU may be configured by the network to decode an extended DCI format for CSI-RS port subset indication. The configuration may include parameters related to legacy CSI-RS resource configuration and CSI reporting. The configuration with extended DCI format may include one or more bit fields (e.g., new bit fields) to indicate which CSI-RS port subset to be used.

[0224] The network may divide the total number of CSI-RS ports X into Y subsets (e.g., X = 64, Y = 2) to indicate which set of 32 CSI-RS ports subset is to be used. The CSI-RS port subset may be represented as a binary pattern or index within the extended DCI format.

[0225] The WTRU may receive configuration from the gNB for one or more CSI-RS resource sets (e.g., each comprising multiple CSI-RS resources). The CSI-RS resource sets may be associated with specific transmission parameters (e.g., periodicity, subcarrier, spacing, and bandwidth parts). The CSI-RS resource sets may be associated with specific CSI-RS port subset (e.g., to enable the WTRU to correlate the DCI indication with appropriate CSI-RS resource set for CSI measurement).

[0226] The configuration may include parameters related to CSI reporting (e.g., including reporting periodicity, report format, quantization levels, and triggering conditions). The configuration may indicate the uplink resources to be used for CSI report transmission (e.g., PUCCH or PUSCH).

[0227] The WTRU may (e.g., continuously) monitor the PDCCH for decoding the extended DCI format addressed to its specific RNTI.

[0228] The WTRU may decode the relevant extended DCI format. The WTRU may base reception capabilities on the CSI-RS resources corresponding to the indicated CSI-RS port subset. The subset may be an index or a binary pattern within the respective DCI.

[0229] The WTRU may receive CSI-RS resources. The WTRU may measure relevant performance metrics (e.g., RSRP, SINR, interference, anomalies, etc.) on the indicated CSI-RS port subset.

[0230] The WTRU may use the measurements to generate a CSI report. The report may include CSI quantities (e.g., CQI, RI, and / or PMI). CSI-RS port subset feedback may be provided by the WTRU as part of the CSI report (e.g., to provide metrics related to the performance, interference, anomalies, etc.).

[0231] The WTRU may provide (e.g., within the CSI report) CSI-RS port subset performance metrics (e.g., RSRP, SINR, and / or interference). The WTRU may provide (e.g., within the CSI report) CSI-RS port subset utilization efficiency (e.g., redundancy indication if certain CSI-RS ports within the subset are redundant or overlapping channel information). The WTRU may provide (e.g., within the CSI report) a number (e.g., an optimal number) of CSI-RS port subset or ranking of CSI-port subsets that provides adequate channel estimation with minimum overhead. The WTRU may provide (e.g., within the CSI report) a preferred alternative CSI-RS port subset partitioning to achieve better channel estimation performance.

[0232] The WTRU may provide (e.g., within the CSI report) adjustments in power levels of specific CSI- RS port subset (e.g., to improve channel estimation performance). The WTRU may provide (e.g., within the CSI report) additional information regarding CSI-RS port subset (e.g., anomaly patterns, interference source identification, channel hardening value, etc.).

[0233] The WTRU may transmit the CSI report to the network over the scheduled uplink channel (e.g., PUCCH or PUSCH). The transmission mode (e.g., periodic or aperiodic) may be determined based on the configuration including potential triggering conditions (e.g., SINR value falling below a set threshold).

[0234] The network may receive the CSI report. The network may process the feedback (e.g., to optimize subsequent transmissions to the WTRU). Adjustments may include MCS adaptation based on CQI, spatial-multiplexing / beamforming based on the RI and PMI, and / or modifications to the CSI-RS port subset for future transmissions (e.g., based on the CSI-RS port subset feedback within the CSI report).

[0235] The WTRU may continue to monitor the PDCCH for updated DCIs. The WTRU may adapt its CSI measurements and reporting. For example, the WTRU may receive (e.g., from the network entity) a second DCI that indicates a second TCI state. The WTRU may determine, based on the indication of the second TCI state, a second set of CSI-RS ports. The WTRU may determine a second transmission slot associated with the second set of CSI-RS ports and a second set of CSI-RS resource elements associated with the second transmission slot. The WTRU may send the CSI report using the second set of CSI-RS resource elements.

[0236] FIG.6 illustrates an example technique for reporting CSI. As shown, the WTRU may be configured by a gNB for extended DCI format for CSI-RS port subset indication. The WTRU may monitor PDCCH. The WTRU may decode the extended DCI format to extract the indicated CSI-RS port subset. The WTRU may receive the indicated CSI-RS ports. The WTRU may perform measurements (e.g., RSRP, SINR, and / or interference).

[0237] The WTRU may generate a CSI report including CSI-RS port subset feedback. The WTRU may transmit the CSI report to the gNB (e.g., over PUCCH and / or PUSCH). The gNB may process the feedbackto optimize future transmissions. For example, the gNB may modify the CSI-RS port subsets partitioning. The WTRU may (e.g., continuously / persistently) monitor PDCCH for updated DCI and measurements.

[0238] If the WTRU receives a CSI configuration to support N CSI ports (e.g., where the N CSI ports are spread over more than one transmission slot), the WTRU may be configured with a multi-PUSCH transmission for CSI reporting.

[0239] The WTRU may receive a CSI configuration of a CSI-RS resource with N CSI ports (e.g., where M subsets of the N CSI-RS ports may be mapped to a same or different sets of CSI-RS REs in M different slots). The WTRU may be configured with M1 multi-PUSCH transmission (e.g., where M1<=M). M1 may represent the number of subsets to be reported.

[0240] PUSCHconfig may include multiple multi-PUSCH TDRA tables (e.g., pusch- TimeDomainAllocationListForMultiPUSCH). For example, in each multi-PUSCH TDRA table, a row (e.g., one row) may be configured with one or multiple SLIVs (e.g., one per PUSCH) (e.g., where the SLIV determines the number of symbols per PUSCH). A multi-PUSCH TDRA tables (e.g., each configured multi- PUSCH TDRA table) may correspond to one of M1 cases.

[0241] The WTRU may receive a dynamic indication (e.g., a DCI) to report CSI of M1 subsets of M subsets and report the corresponding CSI of each subset over M1 sequential configured PUSCH resources. The indication may include a field to indicate M1 subsets of M subsets. The dynamic indication (e.g., a DCI) may carry an indication to select one of the TDRA tables according to the indicated M1 value.

[0242] If PUSCHconfig include one (e.g., only one) multi-PUSCH TDRA table (e.g., pusch- TimeDomainAllocationListForMultiPUSCH) with M1>M, the first M PUSCH occasion may be used for CSI report, and the remaining may be used for UL-SCH.

[0243] Systems, methods, devices, and instrumentalities are described herein related to the determination of co-phasing with partitioned channel state information (CSI) resources.

[0244] A device (e.g., a wireless transmit / receive unit (WTRU)) may receive information that indicates a first set of channel state information reference signal (CSI-RS) resources associated with a first set of CSI- RS ports and a second set of CSI resources associated with a second set of CSI-RS ports. The device may receive a CSI-RS in at least one of the first set of CSI-RS resources or the second set of CSI-RS resources. The device may determine a measurement based on the CSI-RS. The device may determine, based on the measurement, a first precoding matrix indicator (PMI) for the first set of CSI-RS resources and a second PMI for the second set of CSI-RS resources. The device may send, to a network entity, a channel state information (CSI) report, wherein the CSI report indicates the first PMI and the second PMI.

[0245] One or more of the CSI-RS resources in the first set of CSI-RS resources may be in the second set of CSI-RS resources. The CSI report may further indicate a quantized co-phasing measurement associated with the first set of CSI-RS resources and the second set of CSI-RS resources.

[0246] None of the CSI-RS resources in the first set of CSI-RS resources may be in the second set of CSI-RS resources. The CSI report may further indicate measured co-phasing across the first set of CSI-RS ports and the second set of CSI-RS ports.

[0247] Although features and elements described above are described in particular combinations, each feature or element may be used alone without the other features and elements of the preferred embodiments, or in various combinations with or without other features and elements.

[0248] Although the implementations described herein may consider 3GPP specific protocols, it is understood that the implementations described herein are not restricted to this scenario and may be applicable to other wireless systems. For example, although the solutions described herein consider LTE, LTE-A, New Radio (NR) or 5G specific protocols, it is understood that the solutions described herein are not restricted to this scenario and are applicable to other wireless systems as well. For example, while the system has been described with reference to a 3GPP, 5G, and / or NR network layer, the envisioned embodiments extend beyond implementations using a particular network layer technology. Likewise, the potential implementations extend to all types of service layer architectures, systems, and embodiments. The techniques described herein may be applied independently and / or used in combination with other resource configuration techniques.

[0249] The processes described herein may be implemented in a computer program, software, and / or firmware incorporated in a computer-readable medium for execution by a computer and / or processor. Examples of computer-readable media include, but are not limited to, electronic signals (transmitted over wired and / or wireless connections) and / or computer-readable storage media. Examples of computer- readable storage media include, but are not limited to, a read only memory (ROM), a random access memory (RAM), a register, cache memory, semiconductor memory devices, magnetic media such as, but not limited to, internal hard disks and removable disks, magneto-optical media, and / or optical media such as compact disc (CD)-ROM disks, and / or digital versatile disks (DVDs). A processor in association with software may be used to implement a radio frequency transceiver for use in a WTRU, terminal, base station, RNC, and / or any host computer.

[0250] It is understood that the entities performing the processes described herein may be logical entities that may be implemented in the form of software (e.g., computer-executable instructions) stored in a memory of, and executing on a processor of, a mobile device, network node or computer system. That is, the processes may be implemented in the form of software (e.g., computer-executable instructions) storedin a memory of a mobile device and / or network node, such as the node or computer system, which computer executable instructions, when executed by a processor of the node, perform the processes discussed. It is also understood that any transmitting and receiving processes illustrated in figures may be performed by communication circuitry of the node under control of the processor of the node and the computer-executable instructions (e.g., software) that it executes.

[0251] The various techniques described herein may be implemented in connection with hardware or software or, where appropriate, with a combination of both. Thus, the implementations and apparatus of the subject matter described herein, or certain aspects or portions thereof, may take the form of program code (e.g., instructions) embodied in tangible media including any other machine-readable storage medium wherein, when the program code is loaded into and executed by a machine, such as a computer, the machine becomes an apparatus for practicing the subject matter described herein. In the case where program code is stored on media, it may be the case that the program code in question is stored on one or more media that collectively perform the actions in question, which is to say that the one or more media taken together contain code to perform the actions, but that – in the case where there is more than one single medium – there is no requirement that any particular part of the code be stored on any particular medium. In the case of program code execution on programmable devices, the computing device generally includes a processor, a storage medium readable by the processor (including volatile and non-volatile memory and / or storage elements), at least one input device, and at least one output device. One or more programs that may implement or utilize the processes described in connection with the subject matter described herein, e.g., through the use of an API, reusable controls, or the like. Such programs are preferably implemented in a high level procedural or object oriented programming language to communicate with a computer system. However, the program(s) can be implemented in assembly or machine language, if desired. In any case, the language may be a compiled or interpreted language, and combined with hardware implementations.

[0252] Although example embodiments may refer to utilizing aspects of the subject matter described herein in the context of one or more stand-alone computing systems, the subject matter described herein is not so limited, but rather may be implemented in connection with any computing environment, such as a network or distributed computing environment. Still further, aspects of the subject matter described herein may be implemented in or across a plurality of processing chips or devices, and storage may similarly be affected across a plurality of devices. Such devices might include personal computers, network servers, handheld devices, supercomputers, or computers integrated into other systems such as automobiles and airplanes.

[0253] In describing preferred embodiments of the subject matter of the present disclosure, as illustrated in the Figures, specific terminology is employed for the sake of clarity. The claimed subject matter, however, is not intended to be limited to the specific terminology so selected, and it is to be understood that each specific element includes all technical equivalents that operate in a similar manner to accomplish a similar purpose.

Claims

CLAIMS What is Claimed:

1. A wireless transmit / receive unit (WTRU) comprising: a processor configured to: receive information that indicates a first channel state information reference signal (CSI- RS) resource associated with a first set of CSI-RS ports and a second CSI-RS resource associated with a second set of CSI-RS ports; receive a CSI-RS in the first CSI-RS resource and the second CSI-RS resource; determine a first measurement based on the CSI-RS received in the first CSI-RS resource, and a second measurement based on the CSI-RS received in the second CSI-RS resource; determine a first precoding matrix indicator (PMI) associated with the first CSI-RS resource based on the first measurement and a second PMI associated with the second CSI-RS resource based on the second measurement; and send, to a network entity, a channel state information (CSI) report, wherein the CSI report indicates the first PMI and the second PMI.

2. The WTRU of claim 1, wherein the first CSI-RS resource and the second CSI-RS resource are in a CSI- RS resource set.

3. The WTRU of claim 2, wherein the CSI report further indicates a quantized co-phasing measurement between the first PMI and the second PMI.

4. The WTRU of claim 1, wherein the first CSI-RS resource is in a first CSI-RS resource set, the second CSI-RS resource is in a second CSI-RS resource set, different from the first CSI-RS resource set, and the CSI report further indicates measured co-phasing across the first PMI and the second PMI.

5. The WTRU of claim 1, wherein the processor is further configured to: determine the first measurement based on a first polarization of CSI-RS ports in the first set of CSI- RS ports; and determine the second measurement based on a second polarization of CSI-RS ports in the second set of CSI-RS ports, wherein the second polarization is different from the first polarization.

6. The WTRU of claim 1, wherein the information further indicates a third CSI-RS resource associated with a third set of CSI-RS ports and a fourth CSI-RS resource associated with a fourth set of CSI-RS ports, and the processor is further configured to: receive the CSI-RS in the third CSI-RS resource and the fourth CSI-RS resource; determine a third measurement based on the CSI-RS received in the third CSI-RS resource, and a fourth measurement based on the CSI-RS received in the fourth CSI-RS resource; and determine a third PMI associated with the third CSI-RS resource based on the third measurement, and a fourth PMI associated with the fourth CSI-RS resource based on the fourth measurement, wherein the CSI report further indicates the third PMI and the fourth PMI.

7. The WTRU of claim 1, wherein the processor is further configured to determine, based on a time-based recursive pattern, which one or more CSI-RS resources, of the first CSI-RS resource and the second CSI- RS resource, in which to receive the CSI-RS.

8. The WTRU of claim 1, wherein the information further indicates a third CSI-RS resource associated with a third set of CSI-RS ports, the second CSI-RS resource and the third CSI-RS resource are multiplexed in at least one of time or frequency resources, and the processor being configured to determine the second measurement based on the CSI-RS received in the second CSI-RS resource comprises the processor being configured to: aggregate the second CSI-RS resource and the third CSI-RS resource to generate a combined CSI-RS resource; and determine the second measurement based on the CSI-RS received in the combined CSI-RS resource.

9. The WTRU of claim 1, wherein the CSI-RS is a first CSI-RS, the CSI report is a first CSI report, and the processor is further configured to: based on the first CSI-RS resource, the second CSI-RS resource, and a pattern for assigning ports to CSI-RS resources, determine a third CSI-RS resource associated with a third set of CSI-RS ports and a fourth CSI-RS resource associated with a fourth set of CSI-RS ports; receive a second CSI-RS in the third CSI-RS resource and the fourth CSI-RS resource; determine a third measurement based on the second CSI-RS received in the third CSI-RS resource, and a fourth measurement based on the second CSI-RS received in the fourth CSI-RS resource; determine a third PMI associated with the third CSI-RS resource based on the third measurement, and a fourth PMI associated with the fourth CSI-RS resource based on the fourth measurement; andsend, to the network entity, a second CSI report, wherein the second CSI report indicates the third PMI and the fourth PMI.

10. The WTRU of claim 1, wherein the first set of CSI-RS ports comprises a first plurality of ports mapped to the first CSI-RS resource, and the second set of CSI-RS ports comprises a second plurality of ports mapped to the second CSI-RS resource.

11. A method, performed by a wireless transmit / receive unit (WTRU), the method comprising: receiving information that indicates a first channel state information reference signal (CSI-RS) resource associated with a first set of CSI-RS ports and a second CSI-RS resource associated with a second set of CSI-RS ports; receiving a CSI-RS in the first CSI-RS resource and the second CSI-RS resource; determining a first measurement based on the CSI-RS received in the first CSI-RS resource, and a second measurement based on the CSI-RS received in the second CSI-RS resource; determining a first precoding matrix indicator (PMI) associated with the first CSI-RS resource based on the first measurement and a second PMI associated with the second CSI-RS resource based on the second measurement; and sending, to a network entity, a channel state information (CSI) report, wherein the CSI report indicates the first PMI and the second PMI.

12. The method of claim 11, wherein the first CSI-RS resource and the second CSI-RS resource are in a CSI-RS resource set.

13. The method of claim 12, wherein the CSI report further indicates a quantized co-phasing measurement between the first PMI and the second PMI.

14. The method of claim 11, wherein the first CSI-RS resource is in a first CSI-RS resource set, the second CSI-RS resource is in a second CSI-RS resource set, different from the first CSI-RS resource set, and the CSI report further indicates measured co-phasing across the first PMI and the second PMI.

15. The method of claim 11, wherein the method further comprises: determining the first measurement based on a first polarization of CSI-RS ports in the first set of CSI-RS ports; anddetermining the second measurement based on a second polarization of CSI-RS ports in the second set of CSI-RS ports, wherein the second polarization is different from the first polarization.

16. The method of claim 11, wherein the information further indicates a third CSI-RS resource associated with a third set of CSI-RS ports and a fourth CSI-RS resource associated with a fourth set of CSI-RS ports, and the method further comprises: receiving the CSI-RS in the third CSI-RS resource and the fourth CSI-RS resource; determining a third measurement based on the CSI-RS received in the third CSI-RS resource, and a fourth measurement based on the CSI-RS received in the fourth CSI-RS resource; and determining a third PMI associated with the third CSI-RS resource based on the third measurement, and a fourth PMI associated with the fourth CSI-RS resource based on the fourth measurement, wherein the CSI report further indicates the third PMI and the fourth PMI.

17. The method of claim 11, wherein the method further comprises determine, based on a time-based recursive pattern, which one or more CSI-RS resources, of the first CSI-RS resource and the second CSI- RS resource, in which to receive the CSI-RS.

18. The method of claim 11, wherein the information further indicates a third CSI-RS resource associated with a third set of CSI-RS ports, the second CSI-RS resource and the third CSI-RS resource are multiplexed in at least one of time or frequency resources, and determining the second measurement based on the CSI-RS received in the second CSI-RS resource comprises: aggregating the second CSI-RS resource and the third CSI-RS resource to generate a combined CSI-RS resource; and determining the second measurement based on the CSI-RS received in the combined CSI-RS resource.

19. The method of claim 11, wherein the CSI-RS is a first CSI-RS, the CSI report is a first CSI report, and the method further comprises: based on the first CSI-RS resource, the second CSI-RS resource, and a pattern for assigning ports to CSI-RS resources, determining a third CSI-RS resource associated with a third set of CSI-RS ports and a fourth CSI-RS resource associated with a fourth set of CSI-RS ports; receiving a second CSI-RS in the third CSI-RS resource and the fourth CSI-RS resource; determining a third measurement based on the second CSI-RS received in the third CSI-RS resource, and a fourth measurement based on the second CSI-RS received in the fourth CSI-RS resource;determining a third PMI associated with the third CSI-RS resource based on the third measurement, and a fourth PMI associated with the fourth CSI-RS resource based on the fourth measurement; and sending, to the network entity, a second CSI report, wherein the second CSI report indicates the third PMI and the fourth PMI.

20. The method of claim 11, wherein the first set of CSI-RS ports comprises a first plurality of ports mapped to the first CSI-RS resource, and the second set of CSI-RS ports comprises a second plurality of ports mapped to the second CSI-RS resource.

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