Method and apparatus for high Doppler type II CSI measurement and reporting

Abstract

A method performed by a WTRU includes receiving channel state information (CSI) report configuration information indicating a plurality of matrices, a total number of rows and columns for each of the matrices, and an indication to report non-zero coefficients (NZCs); and receiving a CSI reference signal (CSI-RS). The method determines a precoding matrix indicator (PMI) based on channel measurements associated with the CSI-RS, where the PMI comprises, for each matrix: an indication of a total number of NZCs per column for all columns having NZCs in at least one and less than all rows of the matrix; and an indication of a row index for each of the columns having NZC in at least one and less than all rows of the matrix. The method includes reporting the PMI to a network entity.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 335,087 filed on April 26, 2022, U.S. Provisional Patent Application No. 63 / 396,042 filed on August 8, 2022, and U.S. Provisional Patent Application No. 63 / 444,744 filed on February 10, 2023, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present disclosure relates to methods and apparatus for high-Doppler Type II channel state information (CSI) measurement and reporting. BRIEF DESCRIPTION OF THE DRAWINGS

[0004] A more detailed understanding can be obtained from the following detailed description, which is given by way of example in conjunction with its accompanying drawings. As with the detailed description, the figures in such drawings are exemplary. Therefore, the drawings and specific embodiments should not be considered limiting, and other equally effective examples are possible and contemplated. In addition, like reference numerals ("ref.") in the accompanying drawings ("Figures") indicate similar elements, and wherein:

[0005] Figure 1A is a system diagram illustrating an example communication system in which one or more disclosed embodiments may be implemented;

[0006] Figure 1B is an example of an embodiment in which Figure 1A A system diagram of an example wireless transmit / receive unit (WTRU) for use within the illustrated communication system;

[0007] Figure 1C is an example of an embodiment in which Figure 1A a system diagram of an example Radio Access Network (RAN) and an example Core Network (CN) used within the illustrated communication system;

[0008] Figure 1D is an example of an embodiment in which Figure 1A A system diagram of another example RAN and another example CN used within the illustrated communication system;

[0009] Figure 2 is a diagram depicting a high-level demonstration of channel state information (CSI) measurement and reporting in high Doppler;

[0010] Figure 3 depicts a single component pre-decoder used with reference to aspects of the present disclosure;

[0011] Figure 4depicts a plurality of component pre-decoders used with reference to aspects of the present disclosure;

[0012] Figure 5 Depicted are example reporting procedures incorporating methods of reporting non-zero coefficients or zero coefficients in accordance with aspects of the present disclosure;

[0013] Figure 6 Methods of reporting non-zero coefficients in multiple precoders according to aspects of the present disclosure are described;

[0014] Figure 7 Another method of reporting non-zero coefficients in multiple precoders according to aspects of the present disclosure is depicted;

[0015] Figure 8 Depicted Figure 6 An example flow chart of the method described in; and

[0016] Fig. 9 Depicted Figure 7 An example flow chart of the method described in . DETAILED DESCRIPTION

[0017] introduction

[0018] In the following detailed description, many specific details are set forth to provide a thorough understanding of the embodiments and / or examples disclosed herein. However, it should be understood that such embodiments and examples may be practiced without some or all of the specific details set forth herein. In other cases, well-known methods, processes, components, and circuits are not described in detail to avoid blurring the following description. In addition, embodiments and examples not specifically described herein may be practiced in place of embodiments and other examples explicitly, implicitly, and / or inherently described, disclosed, or otherwise provided (collectively referred to as "provided") herein, or practiced in combination with these embodiments and examples.

[0019] Example Communication System

[0020] Figure 1A1 is a diagram illustrating an example communication system 100 in which one or more disclosed embodiments may be implemented. The communication system 100 may be a multiple access system that provides content such as voice, data, video, messaging, broadcast, etc. to multiple wireless users. The communication system 100 may enable multiple wireless users to access such content through sharing of system resources (including wireless bandwidth). For example, the communication system 100 may employ one or more channel access methods such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single carrier FDMA (SC-FDMA), zero tail unique word DFT spread OFDM (ZT UW DTS-s OFDM), unique word OFDM (UW-OFDM), resource block filtered OFDM, filter bank multi-carrier (FBMC), etc.

[0021] like Figure 1A As shown, the communication system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, RAN 104 / 113, CN 106 / 115, public switched telephone network (PSTN) 108, Internet 110 and other networks 112, but it should be understood 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 “STA”) may be configured to send and / or receive wireless signals and may include user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a subscription-based unit, a pager, a cellular phone, a personal digital assistant (PDA), a smart phone, a laptop, a netbook, a personal computer, a wireless sensor, a hotspot or Mi-Fi device, an Internet of Things (IoT) device, a watch or other wearable device, a head-mounted display (HMD), a vehicle, a drone, medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in an industrial and / or automated process chain environment), a consumer electronic device, a device operating on a commercial and / or industrial wireless network, etc. Any of the WTRUs 102a, 102b, 102c, and 102d may be interchangeably referred to as a UE.

[0022] The communication system 100 may also include a base station 114a and / or a base station 114b. Each of the base stations 114a, 114b may be any type of device that is 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 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, an NR Node B, a site controller, an access point (AP), a wireless router, and the like. Although the base stations 114a, 114b are each depicted as a single element, it should be appreciated that the base stations 114a, 114b may include any number of interconnected base stations and / or network elements.

[0023] The base station 114a may be part of the RAN 104 / 113, which may also include other base stations and / or network elements (not shown), such as a base station controller (BSC), a radio network controller (RNC), a relay node, etc. The base station 114a and / or the base station 114b may be configured to send and / or receive wireless signals on one or more carrier frequencies (which may be referred to as cells (not shown)). These frequencies may be in a licensed spectrum, an unlicensed spectrum, or a combination of licensed and unlicensed spectrums. A cell may provide coverage of wireless services to a specific geographic area, which may be relatively fixed or may change over time. The cell may be further divided into cell sectors. For example, a cell associated with the base station 114a may be divided into three sectors. Therefore, in one embodiment, the base station 114a may include three transceivers, i.e., one transceiver 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 send and / or receive signals in a desired spatial direction.

[0024] 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).

[0025] More specifically, as noted above, the communication system 100 may be a multiple access system and may employ one or more channel access schemes such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, etc. For example, the base station 114a in the RAN 104 / 113 and the WTRUs 102a, 102b, 102c may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may use Wideband CDMA (WCDMA) to establish the air interface 116. WCDMA may include communication protocols such as High Speed ​​Packet Access (HSPA) and / or Evolved HSPA (HSPA+). HSPA may include High Speed ​​Downlink Packet Access (HSDPA) and / or High Speed ​​Uplink Packet Access (HSUPA).

[0026] 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) that may establish the air interface 116 using Long Term Evolution (LTE) and / or Advanced LTE (LTE-A) and / or Advanced LTE Pro (LTE-A Pro).

[0027] In one 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).

[0028] In one embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement multiple radio access technologies. For example, the base station 114a and the WTRUs 102a, 102b, 102c may implement LTE radio access and NR radio access together, for example using the dual connectivity (DC) principle. Thus, the air interface utilized by the WTRUs 102a, 102b, 102c may be characterized by multiple types of radio access technologies and / or transmissions transmitted to / from multiple types of base stations (e.g., eNBs and gNBs).

[0029] 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, CDMA2000 1X, CDMA2000EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile Communications (GSM), Enhanced Data rates for GSM Evolution (EDGE), GSM EDGE (GERAN), and the like.

[0030] Figure 1A The base station 114b in may be, for example, a wireless router, a Home NodeB, a Home eNodeB, or an access point, and may facilitate wireless connectivity in a local area, such as a business location, a home, a vehicle, a campus, an industrial facility, an air corridor (e.g., for use by drones), a road, etc., using any suitable RAT. 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 another embodiment, the base station 114b and the WTRUs 102c, 102d may establish a microcell or a femtocell using a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.). Figure 1A As shown, base station 114b may have a direct connection to Internet 110. Therefore, base station 114b may not need to access Internet 110 via CN 106 / 115.

[0031] 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 different quality of service (QoS) requirements, such as different throughput requirements, latency requirements, error tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, etc. The CN 106 / 115 may provide call control, billing services, mobile location-based services, prepaid calling, Internet connectivity, video distribution, etc., and / or perform high-level security functions, such as user authentication. Although not described in detail in the text, the CN 106 / 115 may be 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 different quality of service (QoS) requirements, such as different throughput requirements, latency requirements, error tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, etc. Figure 1AAlthough not shown in the figure, 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 utilize NR radio technology, the CN 106 / 115 may also be in communication with another RAN (not shown) that employs GSM, UMTS, CDMA 2000, WiMAX, E-UTRA, or WiFi radio technology.

[0032] The CN 106 / 115 may also serve as a gateway for the WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the Internet 110, and / or other networks 112. The PSTN 108 may include a circuit-switched telephone network that provides plain old telephone service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices that use common communication protocols, such as the Transmission Control Protocol (TCP), the User Datagram Protocol (UDP), and / or the Internet Protocol (IP) in the TCP / IP Internet protocol suite. The networks 112 may include wired communication networks and / or wireless communication networks owned and / or operated by other service providers. For example, the networks 112 may include another CN connected to one or more RANs, which may employ the same RAT as the RAN 104 / 113 or a different RAT.

[0033] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communication system 100 may include multi-mode capabilities (e.g., the WTRUs 102a, 102b, 102c, 102d may include multiple transceivers for communicating with different wireless networks via different wireless links). Figure 1A The illustrated WTRU 102c may be configured to communicate with the base station 114a, which may employ a cellular-based radio technology, and with the base station 114b, which may employ an IEEE 802 radio technology.

[0034] Figure 1B is a system diagram illustrating an example WTRU 102. Figure 1B As shown, the WTRU 102 may include, among other things, a processor 118, a transceiver 120, a transmit / receive element 122, a speaker / microphone 124, a 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. It will be appreciated that the WTRU 102 may include any sub-combination of the foregoing elements while remaining consistent with an embodiment.

[0035] The processor 118 may be a general purpose processor, a special purpose processor, a conventional processor, a digital signal processor (DSP), a plurality of microprocessors, one or more microprocessors associated with a DSP core, a controller, a microcontroller, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) circuit, any other type of integrated circuit (IC), a state machine, etc. The processor 118 may perform signal decoding, data processing, power control, input / output processing, and / or any other functionality that enables the WTRU 102 to operate in a wireless environment. The processor 118 may be coupled to the transceiver 120, which may be coupled to the transmit / receive element 122. Although Figure 1B The processor 118 and the transceiver 120 are depicted as separate components, but it is understood that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip.

[0036] The send / receive element 122 can be configured to send a signal to a base station (e.g., base station 114a) or receive a signal from the base station by air interface 116. For example, in one embodiment, the send / receive element 122 can be an antenna configured to send and / or receive an RF signal. In one embodiment, the send / receive element 122 can be a transmitter / detector configured to send and / or receive, for example, IR, UV or visible light signals. In another embodiment, the send / receive element 122 can be configured to send and / or receive both RF signals and optical signals. It should be understood that the send / receive element 122 can be configured to send and / or receive any combination of wireless signals.

[0037] Although the transmit / receive element 122 Figure 1B 102 as a single element, but 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.

[0038] The transceiver 120 may be configured to modulate signals to be transmitted by the transmit / receive element 122 and to demodulate signals received by the transmit / receive element 122. As noted above, the WTRU 102 may have multi-mode capabilities. For example, the transceiver 120 may include multiple transceivers to enable the WTRU 102 to communicate via multiple RATs, such as NR and IEEE 802.11.

[0039] The processor 118 of the WTRU 102 may be coupled to a speaker / microphone 124, a keypad 126, and / or a display / touchpad 128 (e.g., a liquid crystal display (LCD) display unit or an organic light emitting diode (OLED) display unit) and may receive user input data therefrom. 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 a non-removable memory 130 and / or a removable memory 132. The non-removable memory 130 may include a random access memory (RAM), a read-only memory (ROM), a hard disk, or any other type of memory storage device. The removable memory 132 may include a subscriber identity module (SIM) card, a memory stick, a secure digital (SD) memory card, and the like. In other embodiments, the processor 118 may access information from and store data in a memory that is not physically located on the WTRU 102, such as on a server or a home computer (not shown).

[0040] The processor 118 may receive power from the power source 134, and may be configured to distribute and / or control power to other components in the WTRU 102. The power source 134 may be any suitable device for powering the WTRU 102. For example, the power source 134 may include one or more dry cell batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel-metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, etc.

[0041] The processor 118 may also be coupled to the GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) regarding the current location of the WTRU 102. In addition to or in lieu of the information from the GPS chipset 136, the WTRU 102 may receive location information from a base station (e.g., base stations 114a, 114b) over the air interface 116 and / or determine its location based on the timing of signals received from two or more nearby base stations. It will be appreciated that the WTRU 102 may acquire location information by any suitable location-determination method while remaining consistent with an embodiment.

[0042] The processor 118 may also be coupled to other peripherals 138, which may include one or more software modules and / or hardware modules that provide additional features, functionality, and / or wired or wireless connectivity. For example, the peripherals 138 may include an accelerometer, an electronic compass, a satellite transceiver, a digital camera (for photos and / or video), a universal serial bus (USB) port, a vibration device, a television transceiver, a hands-free headset, module, a frequency modulation (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, etc. The peripheral device 138 may include one or more sensors, which may be one or more of the following: 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.

[0043] The WTRU 102 may include a full-duplex radio for which transmission and reception of some or all signals (e.g., associated with specific subframes for both uplink (e.g., for transmission) and downlink (e.g., for reception)) may be concurrent and / or simultaneous. The full-duplex radio may include an interference management unit 139 for reducing and / or substantially eliminating self-interference via signal processing performed by hardware (e.g., a choke) or via a processor (e.g., a separate processor (not shown) or via the processor 118). In one embodiment, the WTRU 102 may include a half-duplex radio for which transmission and reception of some or all signals (e.g., associated with specific subframes for both uplink (e.g., for transmission) or downlink (e.g., for reception)) may be concurrent and / or simultaneous.

[0044] Figure 1C 1 is a system diagram illustrating the RAN 104 and the CN 106 in accordance with 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.

[0045] The RAN 104 may include evolved Node-Bs 160a, 160b, 160c, though it will be appreciated that the RAN 104 may include any number of evolved Node-Bs while remaining consistent with an embodiment. The evolved Node-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 evolved Node-Bs 160a, 160b, 160c may implement MIMO technology. Thus, the evolved Node-B 160a, for example, may use multiple antennas to transmit wireless signals to and / or receive wireless signals from the WTRU 102a.

[0046] Each of the evolved Node Bs 160a, 160b, and 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, user scheduling in uplink (UL) and / or downlink (DL), etc. Figure 1C As shown, the eNode-Bs 160a, 160b, 160c may communicate with each other via an X2 interface.

[0047] Figure 1C The illustrated CN 106 may include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (or PGW) 166. While each of the foregoing elements is depicted as being part of the CN 106, it should be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0048] The MME 162 may be connected to each of the evolved Node-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, etc. 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.

[0049] The SGW 164 may be connected to each of the evolved Node-Bs 160a, 160b, 160c in the RAN 104 via an S1 interface. The SGW 164 may generally route and forward user data packets to / from the WTRUs 102a, 102b, 102c. The SGW 164 may perform other functions, such as anchoring the user plane during inter-evolved Node-B handovers, triggering paging when DL data is available for the WTRUs 102a, 102b, 102c, managing and storing the context of the WTRUs 102a, 102b, 102c, and the like.

[0050] 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.

[0051] 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 be in communication with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that acts as an interface between the CN 106 and the PSTN 108. In addition, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired networks and / or wireless networks owned and / or operated by other service providers.

[0052] Although the WTRU Figures 1A to 1D Although described as a wireless terminal, it is contemplated that in certain representative embodiments, such a terminal may (eg, temporarily or permanently) employ a wired communications interface with a communications network.

[0053] In a representative embodiment, the other network 112 may be a WLAN.

[0054] A WLAN in infrastructure basic service set (BSS) mode may have an access point (AP) for the BSS and one or more stations (STA) associated with the AP. The AP may have access or an interface to a distribution system (DS) or another type of wired / wireless network that carries the service to and / or carries the service away from the BSS. Services originating from outside the BSS and leading to the STA may be reached by the AP and may be delivered to the STA. Services originating from the STA and leading to a destination outside the BSS may be transmitted to the AP to be delivered to the corresponding destination. Services between STAs within the BSS may be transmitted by the AP, for example, wherein the source STA may transmit services to the AP, and the AP may deliver services to the destination STA. Services between STAs within the BSS may be considered and / or referred to as point-to-point services. Point-to-point services may be transmitted between the source STA and the destination STA (e.g., directly between them) using a direct link setup (DLS). In certain representative embodiments, the DLS may use 802.11e DLS or 802.11z tunnel DLS (TDLS). A WLAN using an independent BSS (IBSS) mode may not have an AP, and STAs within or using the IBSS (eg, all STAs in the STA) may communicate directly with each other. The IBSS communication mode may sometimes be referred to herein as an "ad hoc" communication mode.

[0055] When using the 802.11ac infrastructure operating mode or a similar operating mode, the AP may send beacons on a fixed channel (such as a primary channel). The primary channel may be a fixed width (e.g., a 20MHz wide bandwidth) or a width dynamically set via signaling. The primary channel may be an operating channel of the BSS and may be used by the STA to establish a connection with the AP. In certain representative embodiments, carrier sense multiple access / collision avoidance (CSMA / CA) may be implemented, for example, in an 802.11 system. For CSMA / CA, a STA (e.g., each STA) (including the AP) may listen to the primary channel. In the case where the primary channel is listened / detected and / or determined to be busy by a specific STA, the specific STA may back off. One STA (e.g., only one station) may transmit at any given time in a given BSS.

[0056] A high throughput (HT) STA may communicate using a 40 MHz wide channel, for example, via a combination of a primary 20 MHz channel and adjacent or non-adjacent 20 MHz channels to form a 40 MHz wide channel.

[0057] Very high throughput (VHT) STA can support 20MHz, 40MHz, 80MHz and / or 160MHz wide channels. 40MHz channels and / or 80MHz channels can be formed by combining continuous 20MHz channels. 160MHz channels can be formed by combining 8 continuous 20MHz channels, or by combining two non-continuous 80MHz channels (this can be called 80+80 configuration). For 80+80 configuration, after channel coding, the data can pass through a segment parser that can divide the data into two streams. Each stream can be processed by inverse fast Fourier transform (IFFT) and time domain processing separately. These streams can be mapped to two 80MHz channels, and data can be sent by the transmitting STA. At the receiver of the receiving STA, the above-mentioned operation for the 80+80 configuration can be reversed, and the combined data can be transmitted to the medium access control (MAC).

[0058] 802.11af and 802.11ah support operating modes below 1GHz. 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 5MHz, 10MHz, and 20MHz bandwidths in the TV White Space (TVWS) spectrum, and 802.11ah supports 1MHz, 2MHz, 4MHz, 8MHz, and 16MHz bandwidths using non-TVWS spectrum. According to a representative embodiment, 802.11ah can support instrument type control / machine type communications, such as MTC devices in macro coverage areas. MTC devices may have certain capabilities, such as limited capabilities, including support for (e.g., only support for) certain bandwidths and / or limited bandwidths. MTC devices may include batteries with battery life above a threshold (e.g., to maintain very long battery life).

[0059] WLAN systems that can support multiple channels and channel bandwidths (such as 802.11n, 802.11ac, 802.11af, and 802.11ah) include channels that can be designated as primary channels. The primary channel may have a bandwidth equal to the maximum common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel may be set and / or limited by a STA (which supports the minimum bandwidth operating mode) from all STAs operating in the BSS. In the example of 802.11ah, for STAs (e.g., MTC-type devices) that support (e.g., only support) a 1MHz mode, the primary channel may be 1MHz wide, even if the AP and other STAs in the BSS support 2MHz, 4MHz, 8MHz, 16MHz, and / or other channel bandwidth operating modes. Carrier sensing and / or network allocation vector (NAV) settings may depend on the state of the primary channel. If the primary channel is busy, for example, because a STA (supporting only a 1MHz operating mode) is sending to the AP, the entire available frequency band may be considered busy even if most of the frequency bands remain idle and may be available.

[0060] In the United States, the available frequency band for 802.11ah is 902MHz to 928MHz. In South Korea, the available frequency band is 917.5MHz to 923.5MHz. In Japan, the available frequency band is 916.5MHz to 927.5MHz. The total bandwidth available for 802.11ah is 6MHz to 26MHz, depending on the country code.

[0061] Figure 1D1 is a system diagram illustrating the RAN 113 and the CN 115 according to one embodiment. As noted above, the RAN 113 may employ NR radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 113 may also be in communication with the CN 115.

[0062] 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 being 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, the gNBs 180a, 180b may utilize beamforming to send signals to and / or receive signals from the gNBs 180a, 180b, 180c. Thus, the gNB 180a may, for example, use multiple antennas to send wireless signals to and / or receive wireless signals from the WTRU 102a. In an embodiment, the gNBs 180a, 180b, 180c may implement carrier aggregation technology. For example, gNB 180a may transmit multiple component carriers to 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, gNBs 180a, 180b, 180c may implement coordinated multi-point (CoMP) techniques. For example, WTRU 102a may receive coordinated transmissions from gNB 180a and gNB 180b (and / or gNB 180c).

[0063] The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using transmissions associated with scalable parameter sets. For example, OFDM symbol spacing and / or OFDM subcarrier spacing may vary for different transmissions, different cells, and / or different portions of the wireless transmission spectrum. The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using subframes or Transmission Time Intervals (TTIs) of varying or scalable lengths (e.g., containing different numbers of OFDM symbols and / or varying absolute time lengths over time).

[0064] 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 a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c while not accessing other RANs (e.g., such as the eNodeBs 160a, 160b, 160c). In a standalone configuration, the WTRUs 102a, 102b, 102c may use one or more of the gNBs 180a, 180b, 180c as mobility anchors. In a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using signals in an unlicensed band. In a non-standalone configuration, the WTRUs 102a, 102b, 102c may communicate / connect with the gNB 180a, 180b, 180c while also communicating / connecting with another RAN, such as the evolved Node-B 160a, 160b, 160c. For example, the WTRUs 102a, 102b, 102c may implement the DC principle to communicate with one or more gNBs 180a, 180b, 180c and one or more evolved Node-Bs 160a, 160b, 160c substantially simultaneously. In a non-standalone configuration, the evolved Node-B 160a, 160b, 160c may act as a mobility anchor for the WTRUs 102a, 102b, 102c, and the gNB 180a, 180b, 180c may provide additional coverage and / or throughput for serving the WTRUs 102a, 102b, 102c.

[0065] Each of the gNBs 180a, 180b, 180c may be associated with a specific cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in uplink (UL) and / or downlink (DL), support of network slicing, dual connectivity, interworking between NR and E-UTRA, routing of user plane data towards a user plane function (UPF) 184a, 184b, routing of control plane information towards an access and mobility management function (AMF) 182a, 182b, etc. As shown in FIG. Figure 1D As shown, gNBs 180a, 180b, and 180c may communicate with each other via an Xn interface.

[0066] Figure 1DThe CN 115 shown may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one session management function (SMF) 183a, 183b, and possible data networks (DNs) 185a, 185b. Although each of the foregoing elements is depicted as part of the CN 115, it should be understood that any of these elements may be owned and / or operated by an entity other than a CN operator.

[0067] The AMF 182a, 182b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via the N2 interface and may act as a control node. For example, the AMF 182a, 182b may be responsible for authenticating users of the WTRU 102a, 102b, 102c, support of network slicing (e.g., handling of different PDU sessions with different requirements), selecting a specific SMF 183a, 183b, management of registration areas, termination of NAS signaling, mobility management, etc. The AMF 182a, 182b may use network slicing in order to customize CN support for the WTRU 102a, 102b, 102c based on the type of services utilized by the WTRU 102a, 102b, 102c. For example, different network slices may be established for different use cases, such as services relying on ultra-reliable low latency (URLLC) access, services relying on enhanced massive mobile broadband (eMBB) access, services for machine type communication (MTC) access, etc. The AMF a82a, 182b 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.

[0068] The SMF 183a, 183b may be connected to the AMF 182a, 182b in the CN 115 via the N11 interface. The SMF 183a, 183b may also be connected to the UPF 184a, 184b in the CN 115 via the N4 interface. The SMF 183a, 183b may select and control the UPF 184a, 184b, and configure traffic routing through the UPF 184a, 184b. The SMF 183a, 183b may perform other functions, such as managing and allocating UE IP addresses, managing PDU sessions, controlling policy enforcement and QoS, providing downlink data notification, etc. The PDU session type may be IP-based, non-IP-based, Ethernet-based, etc.

[0069] The UPF 184a, 184b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via the N3 interface, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices. The UPF 184, 184b may perform other functions, such as routing and forwarding packets, enforcing user plane policies, supporting multi-homed PDU sessions, handling user plane QoS, buffering downlink packets, providing mobility anchoring, etc.

[0070] The CN 115 may facilitate communication with other networks. For example, the CN 115 may include an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that acts as an interface between the CN 115 and the PSTN 108 or may communicate with the IP gateway. In addition, the CN 115 may provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired networks and / or wireless networks owned and / or operated by other service providers. In one embodiment, the WTRUs 102a, 102b, 102c may be connected to the DN 185a, 185b via the N3 interface to the UPF 184a, 184b and the N6 interface between the UPF 184a, 184b and the local data network (DN) 185a, 185b.

[0071] Given that Figures 1A to 1D as well as Figures 1A to 1D Corresponding to the description of the present invention, one or more or all of the functions described herein with reference to one or more of the following may be performed by one or more simulation devices (not shown): WTRU102a-102d, base station 114a-114b, evolved Node B 160a-160c, MME 162, SGW 164, PGW 166, gNB 180a-180c, AMF 182a-182b, UPF 184a-184b, SMF 183a-183b, DN 185a-185b and / or any other device described herein. The simulation device may be one or more devices configured to mimic one or more or all of the functions described herein. For example, the simulation device may be used to test other devices and / or simulate network and / or WTRU functions.

[0072] The simulation device can be designed to implement one or more tests of other devices in a laboratory environment and / or in an operator network environment. For example, one or more simulation devices can perform one or more functions or all functions while being fully or partially implemented and / or deployed as part of a wired and / or wireless communication network in order to test other devices within the communication network. One or more simulation devices can perform one or more functions or all functions while being temporarily implemented / deployed as part of a wired and / or wireless communication network. The simulation device can be directly coupled to another device for testing purposes and / or can perform testing using over-the-air wireless communications.

[0073] One or more simulation devices can perform one or more (including all) functions without being implemented / deployed as part of a wired and / or wireless communication network. For example, the simulation device can be used in a test scenario in a test lab and / or a non-deployed (e.g., testing) wired and / or wireless communication network to implement testing of one or more components. One or more simulation devices can be test equipment. Direct RF coupling and / or wireless communication via RF circuits (e.g., which can include one or more antennas) can be used by the simulation device to send and / or receive data.

[0074] The examples provided herein do not limit the applicability of the subject matter to other wireless technologies, eg, using the same or different principles may be applicable.

[0075] As explained herein, a wireless transmit / receive unit (WTRU) may be an example of a user equipment (UE). Hence, the terms UE and WTRU may be used interchangeably herein.

[0076] Measurement and reporting in traditional systems

[0077] Multiple-Input Multiple-Output (MIMO) technology can enhance capacity, throughput, reliability, and coverage. Accurate channel state information (CSI) is necessary to ensure the gain of MIMO. However, accurate CSI acquisition for MIMO is a tedious and resource-intensive task. When the WTRU moves at higher speeds, the process of acquiring CSI becomes more difficult and resource-intensive.

[0078] 3GPP Release 15 (Release 15) supports a two-level codebook structure, denoted as W=W1W2, where W1 captures the long-term wideband statistics of the channel and W2 captures the fast fading properties of the channel. The W2 matrix contains subband amplitude coefficients and phase coefficients for co-phasing different beams. In Release 15, each of the wideband amplitude coefficients in W1 is quantized with 3 bits and each subband amplitude coefficient in W2 is quantized with 1 bit. The phase combination coefficients in W2 are taken from quadrature phase shift keying (QPSK) or 8PSK. In Release 16 / 17, the W2 matrix is ​​transformed using a discrete Fourier transform (DFT) matrix to make it sparse. This transformation greatly reduces the feedback overhead compared to Release 15. The DFT transformation of W2 in Release 16 / 17, which results in reduced feedback, allows the subband amplitude and phase coefficients to be quantized with more bits. Specifically, in Release 16 / 17, the subband amplitude and phase coefficients are quantized with 3 bits and 4 bits, respectively.

[0079] Release 15, Release 16 / 17 codebooks do not take into account Doppler or its effect on performance. MIMO CSI correction in the presence of high Doppler is not supported in Release 16 / 17. Therefore, Release 18 aims to enhance CSI reporting at medium and high WTRU speeds by exploiting time domain correlation, and to utilize Doppler domain information to assist in downlink (DL) precoding in frequency range 1 (FR1). Release 18 aims to improve the Release 17 Type II codebook without making any modifications to its spatial and frequency domain basis. This release also aims to enhance the reporting of time domain channel properties measured via CSI Reference Signal (RS) CSI-RS for tracking.

[0080] Problems Solved by the Embodiments Disclosed herein

[0081] At high WTRU speeds, the wireless channel changes abruptly and existing MIMO CSI-RS transmission and CSI reporting will not be able to achieve reasonable performance. One primitive strategy to enhance performance is to allocate large resources in both downlink and uplink to handle large amounts of feedback. At high WTRU speeds, the long-term channel statistics of the wireless channel change slowly in time compared to the channel gain. A set of other implementations may be developed by exploiting the long-term channel statistics to take into account channel aging. Several implementations in terms of CSI reporting may also be developed. A set of implementations is provided in the following sections.

[0082] Embodiments disclosed herein

[0083] This document discusses procedures for acquiring CSI in the presence of moderate to high Doppler, procedures for reporting different time domain elements of a CSI report, and procedures for prioritizing different time domain elements of a CSI report.

[0084] Procedure for CSI-RS measurements in the presence of Doppler

[0085] In NR Release 17, the Type II CSI framework is based on multiple sub-functionalities covering wideband and narrowband CSI, beam combining, co-phasing, and frequency compression. The Release 17 framework essentially relies on instantaneous CSI and assumes that the wireless channel does not undergo significant changes between CSI measurement instances. This assumption can be true if the CSI measurement instances are high enough to follow the changes in the channel, however CSI measurement and reporting at high rates results in very high and prohibitive signaling overhead.

[0086] Figure 2 A high-level demonstration of CSI measurement in a high Doppler scenario consisting of two main measurement phases, an initial burst and CSI MIMO measurement, is shown. According to the general procedure, the wireless channel is first sampled at a very high rate to capture the Doppler effect on the channel. Then, by using the configured CSI-RS, the WTRU measures the CSI of the MIMO channel. Using the Doppler effect captured from the first measurement, the WTRU can estimate the trend of channel variations within a short time window and correct the estimated CSI obtainable from the second measurement without the need for additional sampling opportunities. In the illustrated example, measurement 202 is performed using a first set of configured RSs having a frequency domain density D1 and a number of ports P1, and measurement 204 is performed using a second set of configured RSs having a frequency domain density D2 and a number of ports P2.

[0087] Figure 2 The high-level procedure shown has some typical features as follows. The rate of the first reference signal can be high enough to correctly capture the effects of high Doppler on channel characteristics and features. The density of the first reference signal can be no less than the density of the CSI-RS used for MIMO measurements to correctly observe the delay spread of the channel. The number of ports of the first reference signal can be equal to or less than the number of ports of the CSI-RS used for MIMO measurements, because the stability of the MIMO channel can be consistent across different layers.

[0088] In one specific implementation, the procedure for MIMO CSI estimation and reporting in the presence of high Doppler may include one or more of the following:

[0089] In a first example implementation, a WTRU may receive a first reference signal configuration and a second reference signal configuration, both of which are downlink reference signals with a periodic transmission interval of T2.

[0090] In one option, at each reception opportunity defined by T2, the WTRU may receive a first reference signal N1 multiplied by the interval transmission time T1≤T2. The first received reference signal may have a frequency domain density D1 (i.e., transmitted at every x subcarrier position). In addition, the WTRU may measure the first received reference signal on P1 ports.

[0091] In another option, at each reception opportunity marked by T2, the WTRU may receive only a single second reference signal. The second received reference signal may have a frequency domain density D2 (i.e., sent at every x subcarrier position). The density of the second reference signal may be less than the density of the first reference signal (i.e., D2≤D1). In addition, the WTRU may measure the first received reference signal on P1 ports. The number of ports P2 of the second received signal may be greater than or equal to the number of ports P1. (i.e., P2≥P1). The WTRU may receive a second RS with a time offset value Z1 through reception of the first configured RS. In one example, the value of Z1 may be based on the reported WTRU capabilities. The WTRU may report CSI using a reporting configuration associated with the second received reference signal.

[0092] In another option, different combinations of triggering (i.e., periodic, aperiodic, and / or semi-persistent) may be considered for the operation of the first reference signal and the second reference signal. For example, both reference signals may be triggered on a periodic, aperiodic, and / or semi-persistent basis. In another exemplary implementation, in order to manage the overhead associated with the transmission of the reference signals, the second reference signal may be configured based on periodic transmission, while the first reference signal may be triggered aperiodically or in a semi-persistent manner based on the WTRU speed.

[0093] In a second example implementation, the WTRU may receive a first reference signal configuration and a second reference signal configuration, wherein the first reference signal configuration and the second reference signal configuration are an uplink reference signal and a downlink reference signal, respectively, having a periodic transmission interval T2.

[0094] At each reception opportunity defined by T2, the WTRU may transmit a first reference signal N1 multiplied by the interval transmission time T1≤T2. The first transmitted reference signal may have a frequency domain density D1 (i.e., transmitted at every x subcarrier position). In addition, the WTRU may transmit the first configured reference signal on P1 ports. After the transmission of the first reference signal (uplink), the WTRU may receive some Doppler related information from the gNB to assist in CSI prediction for the MIMO channel.

[0095] At each reception opportunity marked by T2, the WTRU may receive only a single second reference signal. The second received reference signal may have a frequency domain density D2 (i.e., transmitted at every x subcarrier position). Here, the density of the second reference signal may be less than the density of the first reference signal (i.e., D2≤D1). In addition, the WTRU may measure the first received reference signal on P1 ports. The number of ports P2 of the second received signal may be greater than or equal to the number of ports P1. (i.e., P2≥P1). The WTRU may receive a second RS with a time offset value Z1 through reception of the first configured RS. The value of Z1 may be based on the reported WTRU capabilities. The WTRU may report CSI using a reporting configuration associated with the second received reference signal.

[0096] Different combinations of triggering (i.e., periodic, aperiodic, and / or semi-persistent) may be considered for the operation of the first reference signal and the second reference signal. For example, both reference signals may be triggered on a periodic, aperiodic, and / or semi-persistent basis. In another exemplary implementation, in order to manage the overhead associated with the transmission of the reference signals, the second reference signal may be configured based on periodic transmission, while the first reference signal may be triggered aperiodically or in a semi-persistent manner based on the WTRU speed.

[0097] The configuration of Sounding Reference Signal (SRS) transmission may be associated with CSI-RS measurements and reporting. The WTRU may send SRS to support the gNB in ​​performing channel measurements at a high rate (i.e., capturing Doppler effects). In addition, the WTRU may receive information related to the effects of high Doppler on the wireless channel. The WTRU may perform CSI measurements on a MIMO channel and report using the configured CSI configuration. The SRS configuration may or may not have the same number of CSI ports as the actual MIMO transmission, even if the configured CSI-RS has the same number of CSI ports as the actual MIMO transmission. The WTRU may receive a single trigger to initiate the transmission of the configured SRS and the reception of the CSI-RS.

[0098] In a third example implementation, the first RS and CSI-RS may be configured by a radio resource control (RRC) and / or a MAC control element (CE) for a specific set of transmission opportunities (i.e., multi-transmission operation), wherein each set of transmission opportunities may also include a combination of one or more of the values ​​of the T1 and T2 time intervals, the D1 and D2 reference signal densities in the frequency domain, the number of ports, the trigger type, etc., wherein each configuration may be selected by dynamic signaling (e.g., DCI).

[0099] Tracking Reference Signal (TRS) Correlation for CSI to CSI

[0100] In one specific implementation, the WTRU may receive a DCI indicating / triggering both a first RS (e.g., an aperiodic tracking RS (A-TRS), a burst format of an A-TRS, a multiple-transmit TRS, a second CSI-RS resource, etc.) and a CSI-RS for CSI, wherein the WTRU may determine a parameter value representing a Doppler effect based on measuring the first RS. Triggering both the first RS and the CSI-RS for CSI may be based on a pre-configured / activated code point of a field of the DCI (e.g., a CSI request field, a separate / new field, and / or an existing field), wherein the code point may be configured by RRC and / or activated via MAC-CE. The code point may indicate at least one measurement timing parameter based on a reception time instance / time slot / symbol of the DCI, and the at least one measurement timing parameter may indicate one or more measurement time instances / time slots / symbols of DL signals of the first RS and the CSI-RS for CSI.

[0101] Hereinafter, for the sake of brevity of discussion, the first RS may be an A-TRS (resource); however, the proposed specific implementations and processes may be similarly (or equivalently or extendedly, etc.) applied to other examples of the first RS (e.g., a burst format of an A-TRS, multiple TRSs, a second CSI-RS resource, etc.).

[0102] In one example, the WTRU may receive a DCI indicating a codepoint at a time slot K (within which the last symbol index of the DCI being received may be L), wherein the codepoint may be preconfigured / activated to indicate that X repetition transmissions of the A-TRS resource are to start M symbols after the last symbol (or a certain symbol) of the DCI being received (e.g., based on the last symbol). The codepoint may (further) be preconfigured / activated to indicate that the CSI-RS resource for the CSI is to be transmitted N symbols after the last symbol (or a certain symbol) of the last (Xth) transmission of the A-TRS resource (e.g., based on the last symbol). In response to receiving the DCI, the WTRU may determine a first measurement symbol for a first repetition transmission of the A-TRS resource to be M symbols after symbol index L of time slot K, and starting from the first measurement symbol (e.g., based on the first measurement symbol), the WTRU may receive (e.g., measure) the X repetition transmissions of the A-TRS resource. The WTRU may derive a parameter value representing the Doppler effect based on receiving / measuring X repetitive transmissions of the A-TRS resource.

[0103] The WTRU may determine a second measurement symbol for starting transmission of CSI-RS resources for CSI based on the first measurement symbols X and N (e.g., where the second measurement symbol may be N symbols after the last symbol (or a symbol) of the last (Xth) transmission of the A-TRS resources (e.g., based on the last symbol). The WTRU may receive (e.g., measure) the CSI-RS resources for CSI based on the second measurement symbol (e.g., starting from the second measurement symbol). The WTRU may determine (e.g., derive) CSI (e.g., RI, precoding matrix indicator (PMI), channel quality indicator (CQI), layer indication (LI), etc.) based on the parameter value representing the Doppler effect and based on measuring the CSI-RS resources for CSI. The WTRU may send (e.g., report) the CSI (and / or the parameter value representing the Doppler effect (to the gNB)), e.g., in a CSI reporting instance / slot / symbol). The CSI reporting instance / slot / symbol may be determined based on the DCI (e.g., based on the (CSI request) field of the DCI). This determination may improve downlink performance based on the CSI being reported being derived based on the use of parameter values ​​representing the Doppler effect. This derivation may improve downlink performance based on flexible / configurable parameters of X, M, and / or N, which may allow for reduced latency between the Xth transmission timing of the A-TRS resource and the transmission timing of the CSI-RS resource for the CSI. This flexibility may reduce signaling overhead in notifying the WTRU of the first measurement symbol and the second measurement symbol, which may be determined by the WTRU based on the DCI reception timing X, M, and / or N.

[0104] The WTRU may (be configured to) separately send / report a parameter value representing the Doppler effect based on measuring the first RS.

[0105] In one specific implementation, the first RS (e.g., A-TRS) may be configured as a portion of the CSI-RS for CSI. The portion of the CSI-RS for CSI may include a subset of antenna ports (APs) for the CSI-RS for CSI, and / or RE positions of a subset of APs, etc. The subset of APs (as the portion of the CSI-RS for CSI) may be determined based on the number of configured APs of the CSI-RS resources.

[0106] In one example, when the number of configured APs for CSI-RS resources for CSI is less than or equal to P1 (e.g., P1=4), the WTRU may determine that the number of APs for the first RS (e.g., corresponding to a subset of APs) is 1.

[0107] In one example, when the number of configured APs for CSI-RS resources for CSI is less than or equal to P2 (e.g., P1=8), the WTRU can determine that the number of APs for the first RS (e.g., corresponding to a subset of APs) is 2.

[0108] In one example, when the number of configured APs for CSI-RS resources for CSI is less than or equal to P3 (e.g., P3=16, 32, etc.), the WTRU can determine that the number of APs for the first RS (e.g., corresponding to a subset of APs) is 4.

[0109] In one example, when the number of configured APs for CSI-RS resources for CSI is less than or equal to P4 (e.g., P4=16, 32, etc.), the WTRU can determine that the number of APs for the first RS (e.g., corresponding to a subset of APs) is 8.

[0110] The determined / indicated RE position / distribution of the AP of the first RS (e.g., in the frequency domain) can be based on the RE position / distribution of the same AP of the CSI-RS resource for CSI. In one example, a subset of APs (e.g., the determined APs of the first RS) can be selected / determined to be evenly spaced (e.g., sampled) in the frequency domain, captured from the APs of the CSI-RS for CSI (e.g., which can correspond to the RE position / distribution of the APs of the first RS).

[0111] Determining the number of APs for the first RS based on the number of APs for CSI-RS for CSI can improve reliability, flexibility, and efficiency in determining / indicating the number of APs for the first RS without the need for separate control signal signaling, and an increased number of APs for the first RS as an increased configured number of APs for CSI-RS for CSI can provide reliability / efficiency when measuring those RSs (for example, in terms of power differences in RE locations / distributions in the frequency domain across those RSs).

[0112] In one implementation, the WTRU may (implicitly) determine that the first RS is associated with the CSI-RS for CSI based on a quasi co-location (QCL) property / configuration of the CSI-RS for CSI. In one example, when the first QCL source is the same as (e.g., the same, associated, linked, has an equivalent QCL chain, etc.) the second QCL source of the CSI-RS for CSI, the WTRU may determine that the first RS has (e.g., is configured with) the first QCL source (e.g., periodic TRS, synchronization signal block (SSB) index, etc.).

[0113] In one example, the WTRU may only expect the first QCL source and / or the second QCL source to be a periodic TRS. In one example, the WTRU may be configured with a second periodic TRS as a QCL source for a CSI-RS for CSI. The WTRU may determine that the first RS is an RS (resource) of a QCL source having a second periodic TRS (e.g., based on the second periodic TRS). The WTRU may determine that the second RS (resource) also has the same QCL source of the second periodic TRS. In response to this determination, the WTRU may determine that the first RS is the nearest RS before the CSI-RS for CSI in the time domain, which may improve reliability and efficiency when estimating the Doppler effect based on the first RS to be used for CSI derived based on the CSI-RS for CSI.

[0114] CSI-RS for CSI

[0115] Enhanced CSI-RS repetition in frequency

[0116] The WTRU determines the CSI-RS configuration in the frequency domain based on Doppler.

[0117] The WTRU may be semi-statically configured with more than one frequency domain density configuration for CSI-RS resource settings (e.g., more than one bitmap for resource block (RB) allocation for CSI-RS), and the WTRU may dynamically select the frequency domain configuration based on Doppler. For example, the WTRU may receive a CSI report setting with a Doppler threshold, and the WTRU may determine the RBs to monitor based on the Doppler. For example, when the Doppler is above the threshold, the WTRU may monitor X RBs, and if the Doppler is below the threshold, the WTRU may monitor Y RBs, where Y>X.

[0118] Alternatively, the WTRU may receive a configuration for a CSI-RS burst that may be defined within an initial set of RBs and a number of repetitions in frequency with an offset parameter. The offset may define the interval between repetitions in frequency. When the Doppler is above a threshold, the WTRU may determine to measure the CSI within the CSI-RS burst that is repeated in frequency. For example, if the WTRU measures a Doppler above a threshold, the WTRU may determine that each even RB may be used to measure CSI and that the CSI-RS transmission in each even RB is a repetition of the first RB. If the WTRU measures a Doppler below a threshold, the WTRU may determine that only the first RB may be used to measure CSI. The WTRU may also determine the number of repetitions based on the Doppler value being above a threshold.

[0119] The WTRU may indicate in the CSI report the frequency domain configuration used by the WTRU to determine the CSI. For example, the WTRU may include a flag or bitmap indicating that the associated CSI (e.g., PMI, rank indicator (RI), LI, CQI, and / or CRI) is conditioned on measurements made on X or Y RBs. Alternatively, the WTRU may include Doppler in the CSI report and implicitly signal X or Y to the network based on the indicated Doppler.

[0120] The WTRU may monitor a subset of all the RBs in a BWP, measure the channels on the subset of RBs, and may report CSI for all the RBs of the BWP. For example, a CSI-RS burst may consist of N < N_PRB (physical resource blocks) consecutive RBs (e.g., RBs 0 to N-1) in the frequency domain, where the WTRU may receive the CSI-RS. The burst may also be configured in terms of the number of resource elements (REs). N_PRB may correspond to the total number of RBs configured in the BWP. The WTRU may determine type II CSI basis function indices and coefficients within the subset of N RBs of the BWP, and the WTRU may report the basis functions and coefficients to the network. The WTRU may indicate in its CSI report (e.g., a one-bit flag in the uplink control information (UCI)) whether the reported CSI was measured within the subset of N RBs or within the entire configured CSI-RS bandwidth N_PRB.

[0121] The burst may be configured to transmit CSI-RS only in a subset of all the PRBs. Even for RBs without CSI-RS, the WTRU may report CSI by applying an extension or prediction function to estimate the channel based on the samples received in the burst. The WTRU may use the prediction function to estimate the channel within N_PRB samples using only N samples from the CSI-RS burst. The WTRU may receive a codebook of prediction functions to use, and the WTRU may report the index of the selected prediction function along with the measurements made on the N samples. The CSI-RS resource setting may be switched between burst mode and non-burst mode based on a flag in the setting. The flag may be semi-statically activated based on a MAC-CE. The WTRU may determine whether to use the prediction function based on the measured Doppler being above a threshold.

[0122] For example, the WTRU may measure a channel vector H_N within N samples. The WTRU may generate an estimate of the size N_PRB of the channel using a prediction function F of dimension N_PRB×N as: H_NPRB=F*H_N. The WTRU may determine F based on a pre-configured codebook of the F function. The WTRU may receive the codebook of F as part of the CSI reporting setup. Alternatively, the WTRU may report H_N only with a flag indicating that the network should use the prediction function. The network may apply the prediction function F and may determine the channel of the WTRU within N_PRB. This method may reduce the overhead of the CSI-RS so that only N samples out of the N_PRB samples may contain the CSI-RS.

[0123] Enhancements to Type II CSI reporting and priority levels for feedback reduction

[0124] Switching between CSI modes

[0125] CSI Mode Definition

[0126] In one specific implementation, one or more CSI modes may be used, where the CSI mode may be associated with one or more of the following seven conditions.

[0127] (1) reporting the bandwidth or type (e.g., subband or wideband) of one or more CSI reporting quantities, including at least one of the following: (a) precoding matrix information associated with a component precoder, wherein the component precoder may be part of a precoding matrix that may include one or more component precoding matrices. For example, a precoding matrix (W) may be defined as W=W1W2, where W1 and W2 may be referred to as a component precoder or a component precoding matrix. Thereafter, a precoding matrix (W) that may include one or more component precoding matrices may be associated with a composite precoding matrix, a composite precoder, a precoder, and / or

[0128] or precoder matrix may be used interchangeably. (b) a channel quality indicator (CQI), wherein the CQI may be estimated, calculated, or determined based on the determined precoding matrix. (c) a rank or number of layers. (d) sub-parameters of a component precoder. For example, a component precoder may include one or more parameters (e.g., power scaling and / or co-phase parameters). In one example, a first CSI mode may be associated with a wideband power scaling (e.g., W2) of a component precoder, and a second CSI mode may be associated with a subband power scaling.

[0129] (2) One or more subband sizes of the CSI reporting volume, where the subband size may determine the number of bits to be reported for the CSI.

[0130] (3) CSI reporting channel / resource. For example, the CSI reporting channel / resource may be at least one of a physical uplink control channel (PUCCH), a physical uplink shared channel (PUSCH), an SRS, and / or a random access channel (RACH) resource (e.g., a physical random access channel (PRACH) preamble and / or a RACH MsgA).

[0131] (4) CSI reporting frequency, where the reporting frequency may include at least one of periodic, aperiodic and / or semi-persistent.

[0132] (5) CSI measurement resources. For example, CSI measurement resources may include SSB, CSI-RS,

[0133] At least one of a TRS, an SRS, a positioning RS (PRS), a demodulation RS (DMRS), and / or a phase tracking reference signal (PTRS). The measurement resources may depend on the CSI pattern, wherein the measurement resources for a specific measurement may be determined based on the CSI pattern. The specific measurement may be at least one of Doppler frequency, mobility, WTRU speed, temporal coherence, Doppler shift, or a QCL parameter.

[0134] (6) Configure the number of transmit receive points (TRPs) used for CSI reporting.

[0135] (7) Number of panels used, assumed, and / or considered for the CSI report.

[0136] CSI mode determination

[0137] In one implementation, one or more CSI patterns may be defined or used, and the WTRU may determine the CSI pattern based on one or more of the following six conditions:

[0138] (1) From the level of measured Doppler frequency. For example, the WTRU may perform a measurement of Doppler frequency, and based on the level of Doppler frequency, the WTRU may determine a CSI pattern, where Doppler frequency may be used interchangeably with WTRU speed, WTRU mobility, channel coherence time, and / or channel time coherence. One or more Doppler frequency thresholds may be used, configured, and / or predetermined; if the measured Doppler frequency is within the threshold, the CSI pattern may be determined.

[0139] (2) The level of frequency selectivity of the channel. For example, the WTRU may perform a measurement of the frequency selectivity of the channel, and the WTRU may determine the CSI pattern based on the measured frequency selectivity. Frequency selectivity may be used interchangeably with delay spread, channel frequency coherence, and / or coherence bandwidth. One or more coherence bandwidth thresholds may be used, configured, and / or predetermined; if the measured coherence bandwidth is within the threshold, the CSI pattern may be determined.

[0140] (3) Uplink resources determined for CSI reporting.

[0141] (4) Measurement resources configured for CSI reporting.

[0142] (5) The number of TRPs associated with the CSI report.

[0143] (6) Number of panels used, assumed, and / or considered for the CSI report.

[0144] In another implementation, the WTRU may be explicitly indicated by the gNB which CSI mode to use. For example, higher layer configurations (e.g., SIB, RRC, and / or MAC-CE) may be used to indicate the CSI mode to be used per carrier, bandwidth part (BWP), CSI reporting configuration, and / or TRP. In another example, a dynamic indication (e.g., DCI) may be used to indicate the CSI mode to be used when a CSI report is triggered and / or for a CSI reporting instance at a future time.

[0145] The WTRU may report CSI based on the determined CSI pattern. The uplink resources and CSI reporting format / content may be determined based on the determined CSI pattern.

[0146] CSI mode indication

[0147] In one implementation, when the CSI pattern is determined implicitly or autonomously, the WTRU may indicate or report the determined CSI pattern. The determined CSI pattern may be referred to as CSI pattern identification (CMI) hereinafter, but may be used interchangeably with Doppler frequency pattern (CFM), WTRU speed-based CSI pattern (USM), etc. The WTRU may report the CMI based on one or more of the following three conditions.

[0148] (1) One or more uplink resources may be configured or used, and each uplink resource may be associated with a CSI pattern. The WTRU may determine the uplink resource based on the determined CMI and report its associated CSI. The one or more uplink resources may be mutually orthogonal in the time domain, frequency domain, code domain, and / or spatial domain.

[0149] (2) CMI may also be reported as part of CSI. For example, when the WTRU reports CSI that may depend on the determined CMI, the WTRU may report CMI together with CSI. CMI may be encoded separately from its associated CSI. Therefore, the receiver may first perform decoding of CMI to determine the information size of CSI and perform decoding of its associated CSI. CMI may be jointly encoded with its associated CSI; the receiver may perform blind decoding on CMI and its associated CSI.

[0150] (3) CMI may be reported before its associated CSI is reported. For example, CMI may be reported periodically, and the CMI reported for CSI at slot #n may be determined based on the latest CMI reported nx slots earlier, where x may be the processing time.

[0151] Method for reporting indices of non-zero subband coefficients

[0152] Figure 3 An example of a single common phase coefficient matrix W_2 or component pre-decoder W_2 is provided in FIG. Figure 3 In W_2, each row indicates a polarization of a beam. The number of rows indicates the number of beams multiplied by the number of polarizations. In one example, the component precoder in W_2 has L=2 beams, and each beam has 2 polarizations. Figure 3 The component precoders in thus have 4 rows. Each column indicates a DFT vector, and the number of columns indicates the number of DFT vectors.

[0153] In the following: the polarization of a beam may be used interchangeably with a row. The DFT vector may be used interchangeably with a column. The number of beams multiplied by the polarization may be used interchangeably with the number of rows. The number of DFT vectors may be used interchangeably with the number of columns.

[0154] Due to the frequency domain compression of the component precoder, not all coefficients of the component precoder are non-zero. Non-zero coefficients (NZC) are represented by 1, and zero coefficients (ZC) are represented by 0. Non-zero coefficients can be used interchangeably with 1. Zero coefficients can be used interchangeably with 0.

[0155] The WTRU needs to report L beams and M v The number of non-zero coefficients can be defined as a function of the number of W_2 matrices and / or the number of rows and / or the number of columns and / or the frequency domain compression scaling factor β. The number of non-zero coefficients in each W_2 matrix can be defined as where β is the frequency domain compression scaling factor, M1 is the number of DFT vectors in a layer, and L is the number of beams with 2 polarizations. The number of NZCs on each layer is defined as where l = 1, ..., v, and where v is the total number of layers, and the number of non-zero coefficients on all layers is defined as Length 2LM v A bitmap may be used to indicate the index of a zero coefficient and a non-zero coefficient. In the bitmap, the use of "1" is used to indicate the index of a non-zero coefficient, and the use of "0" may be used to indicate a zero coefficient.

[0156] For rapidly changing channels, the long term channel statistics such as component precoder W_1 may remain constant for a longer duration. However, for rapidly changing channels, such as wireless channels that the WTRU experiences at high speeds, the common phase coefficients or component precoders W_2 will change at a faster rate. At high WTRU speeds, the WTRU may report one or more component precoders W_2 for a fixed component precoder W_1. In one example, the WTRU may report Q component precoders W_2 for a single component precoder W_1. This may reduce the total number of non-zero coefficients from Increase to For illustration purposes, the Q=3 common phase coefficient matrix with L=2 beams and M=4 DFT is as follows Figure 4 shown.

[0157] Method 1

[0158] The WTRU may report a combination of beam and DFT vector index. As an illustrative example, in the case of L beams and M v K0 NZCs on vectors can be formed different combinations, where (.)! is a factorial operation. The number of bits required to indicate the index of K0 NZCs is When the number of NZC K0 is equal to The maximum number of beam and DFT vector combinations associated with NZC occurs when . This can be mathematically proven to be Therefore, with the length 2LM v This type of report can achieve smaller feedback overhead compared to bitmap.

[0159] The feedback overhead associated with the combined report increases with increasing K0. The feedback overhead is v / 2, and then begins to decrease until K0 reaches K0=2LM v Therefore, when K0=10 or K0=2LM v When K0≤LM v / 2 or K0≥1.5LM vWhen K0 is increased, less feedback overhead can be achieved. However, when K0 is increased, the feedback overhead associated with reporting the coefficient values ​​of NZC (i.e., subband and phase coefficient values) also increases. Therefore, for overall feedback reduction, it is wise to ensure that K0 ≤ LM v / 2, which can be achieved by introducing the frequency domain parameter p v and smaller values ​​of β.

[0160] In one example method, the WTRU may switch the reporting procedure for reporting the position and / or index of non-zero coefficients from a first procedure to a second procedure. The first procedure may involve or result in the generation of a bitmap of length 2LM_v, and the second procedure may involve or result in the generation of a bitmap of length The bitmap is generated, where K o It can be an upper bound on the number of non-zero coefficients in component precoder W_2, or K o It can be the actual number of non-zero coefficients in component precoder W_2.

[0161] The WTRU may perform one or more of the following six options.

[0162] (1) The WTRU may determine the number of non-zero coefficients in one or more component precoders.

[0163] (2) The WTRU may determine a threshold value regarding the number of non-zero coefficients. In one example, the WTRU may determine the threshold value as: (a) the number of non-zero coefficients is less than and / or equal to a first threshold value (e.g., threshold value a), and / or (b) the number of non-zero coefficients is greater than and / or equal to a second threshold value (e.g., threshold value b).

[0164] (3) The WTRU may determine whether the number of zero coefficients is greater than, equal to, or less than the number of non-zero coefficients.

[0165] (4) The WTRU may determine threshold "a" and / or threshold "b" based on its capabilities.

[0166] (5) The WTRU may perform: a reporting procedure, such as the first reporting procedure or the second reporting procedure; and a reporting type, such as reporting a non-zero coefficient (NZC) or a zero coefficient (ZC). The WTRU may perform Figure 5 The exemplary procedure depicted in to determine when to use the first reporting procedure or the second reporting procedure and when to report a NZC or ZC type report. In one example, when reporting the position of the NZC for one or more component precoders, where: (a) the threshold "a" is less than half of the total number of coefficients. (b) the threshold "b" is greater than half of the total number of coefficients.

[0167] (6) Based on threshold "a", threshold "b", the number of NZCs and / or the number of ZCs, the WTRU may perform one or more of the following: (a) The WTRU may report an indication of the reporting procedure (e.g., the first procedure or the second procedure) in the CSI report carrying the component precoder. (B) The WTRU may report an indication of the reporting type (e.g., reporting the location of the NZC or the location of the ZC) in the CSI report carrying the component precoder.

[0168] In an alternative example method, the WTRU may receive a configuration via (eg, SIB, RRC, and / or MAC-CE) or a more dynamic DCI indication to report the location of the NZC or ZC using the first procedure or the second procedure.

[0169] Method 2

[0170] Due to frequency domain compression, the component precoder W_2 is a sparse matrix. Reporting the position of NZC in multiple W_2 matrices requires large feedback overhead.

[0171] In one example method, the WTRU may perform one or more of the following.

[0172] For each component pre-decoder W_2 (e.g., for Figure 3 In one example, the WTRU may first use the first indication (e.g., UCI in Q = 3 for each of the component precoders in the W_2 matrix) to report the number of 1s on each column of the W_2 matrix. (b) The WTRU may report the number of NZCs on each column of the W_2 matrix only if the following conditions are met: v - 1 column (e.g., only for the first M v -1 columns) reports the number of 1s in the columns. If the WTRU reports the total number of 1s in the W_2 matrix (e.g., as in Release 16 reporting of type I IPMI).

[0173] The WTRU may use the second indication to report the row index of 1 for each column of the component precoder W_2. (a) In one example, a single row index may include an indication or identification of the position of the row in the column where the NZC exists. Multiple row indices may indicate the row identification / position of the NZC in multiple columns of each precoder matrix. (a) In one example, the WTRU may use the second indication (e.g., UCI in The bitmap of the digits, where a j(a) The WTRU may report the row index of the 1s in each column of the W_2 matrix if the number of 1s in the column is at least one and the number of 1s in the column is less than the number of rows in the W_2 matrix.

[0174] An overview of using method 2 to report NZC locations (e.g., column and row indices of 1 in the matrix) is given in Figure 6 Described in detail in.

[0175] exist Figure 6 In step 1 of , the WTRU / UE determines whether the total number of 1s in the W_2 matrix has been reported. Or does the gNB know the total number of 1s]. If not, the WTRU proceeds to step 2 for all columns of the W_2 matrix. If known, the WTRU proceeds to step 2 for M columns of the W_2 matrix. v -1 column goes to step 2. For example, the first M v -1 column.

[0176] In either case, at step 2, the WTRU determines the number of 1s in each column (e.g., all columns or the first M_v-1 columns) specified after step 1. For example, the number of 1s in column j is a_i. The WTRU also reports the number of 1s in each column. For example, the WTRU reports a_i=x for column j.

[0177] exist Figure 6 At step 3, the WTRU determines whether the reported number of 1s in the column meets the following criteria: (1) The reported number of 1s in the column is zero. For example, a_i = 0. (2) The reported number of 1s in the column is equal to the number of rows. For example, a_i = 2L.

[0178] If the condition of step 3 is not met, then at step 4a the WTRU reports a row index of 1 in column j. If the condition of step 3 is met, then at step 4b the UE / WTRU does not report a row index of 1 in column j.

[0179] exist Figure 6 At step 5 of , if the WTRU has reported the total number of 1s in the W_2 matrix, the WTRU reports the row index of the 1 in the last column (e.g., the M_vth column) only if (1) the number of 1s in the last column is greater than one or (2) the number of 1s in the last column is less than the number of rows. Figure 6 One benefit of the procedure is that the precoding matrix information is more efficiently communicated to the network entity by reducing the amount of data to be sent.

[0180] Method 3

[0181] In one example method, the WTRU may perform one or more of the following.

[0182] For each component pre-decoder W_2 (e.g., for Figure 4 In one example, the WTRU may first use the first indication (e.g., UCI in Q = 3 component precoders for each component precoder), the WTRU may first use the first indication to report the number of 1s on each row of the W_2 matrix. (b) The WTRU may report the number of 1s in a row for only 2L-1 rows of the W_2 matrix (e.g., only for the first 2L-1 rows) if the following conditions are met: If the WTRU reports the total number of 1s in the W_2 matrix (e.g., as in Release 16 reporting of Type I IPMI).

[0183] The WTRU may use a second indication to report the column index of 1 for each row of component precoder W_2. (a) In one example, the WTRU may use a second indication (e.g., UCI in The bitmap of the digits, where α l (a) The WTRU may report the column index of the 1s in each row of the W_2 matrix only if the number of 1s in the row is at least one and the number of 1s in the row is less than the number of columns in the W_2 matrix.

[0184] An overview of using method 3 to report NZC locations (e.g., column and row indices of 1 in the matrix) is given in Figure 7 Detailed description in Figure 7 In, use Figure 6 A similar procedure as in , but reverse the use of rows and columns for different numbers of elements in the W_2 matrix and repeat step 2 to configure the report.

[0185] exist Figure 7 In step 1 of , the WTRU / UE determines whether the total number of 1's in the W_2 matrix has been reported. If not, the WTRU proceeds to step 2 for all rows of the W_2 matrix. If yes, the WTRU proceeds to step 2 for 2L-1 rows of the W_2 matrix. For example, the first 2L-1 rows.

[0186] In either case, at step 2, the WTRU determines the number of 1s in each row (e.g., all rows or the first 2L-1 rows) specified after step 1. For example, the number of 1s in row I is a_iI. The WTRU also reports the number of 1s in each row. For example, the WTRU reports a_I=x for row I.

[0187] exist Figure 7 At step 3, the WTRU determines whether the reported number of 1s in the row meets the following criteria: (1) The reported number of 1s in the row is zero. For example, a_I=0. (2) The reported number of 1s in the row is equal to the number of columns. For example, a_I=M v .

[0188] If the condition of step 3 is not met, then at step 4a, the WTRU reports the column index of 1 in row 1. If the condition of step 3 is met, then at step 4b, the WTRU does not report the column index of 1 in row 1.

[0189] exist Figure 7 At step 5 of , the WTRU has reported the total number of 1s in the W_2 matrix. The WTRU reports the column index of the 1 in the last row only if (1) the number of 1s in the last row is greater than one or (2) the number of 1s in the last row is less than the number of columns. Figure 7 One benefit of the procedure is that the precoding matrix information is more efficiently communicated to the network entity by reducing the amount of data to be sent.

[0190] Figure 8 800 is an example method of method 2. The method 800 may be performed by a WTRU / UE. At 802, the WTRU receives channel state information (CSI) reporting configuration information. The configuration information indicates (i) a plurality of matrices, (ii) a total number of rows and columns for each of the plurality of matrices, and (iii) an indication of reporting non-zero coefficients (NZC) useful for pre-decoder matrix information.

[0191] At 804, the WTRU receives one or more channel state information reference signals (CSI-RS).

[0192] At 806, the WTRU determines a precoding matrix indicator (PMI) based on channel measurements associated with one or more CSI-RSs. Here, for each matrix in the plurality of matrices, the PMI includes: (a) an indication of the total number of NZCs for each column for all columns having NZCs in at least one and less than all rows of the matrix; and (b) an indication of a row index for each column of each column having NZCs in at least one and less than all rows of the matrix.

[0193] At 808, the WTRU may report the PMI to a network entity such as a gNB, a base station, or another WTRU.

[0194] In the method 800, the WTRU may determine the PMI using indications of the NZC for each column and row. These indications may have binary values ​​of zero or one.

[0195] In method 800, the WTRU may determine the PMI by generating information where any indication in a row corresponds to a polarization of a beam and where any indication in a column corresponds to a DFT vector.

[0196] In method 800, the WTRU may report the PMI to the network entity such that the PMI is reported lacking an NZC value for any column having an all-zero coefficient indicator. Furthermore, such reporting may include reporting the PMI with a row index including an identification or location indication of the row in the column having the NZC value.

[0197] Fig. 9 900 is an example method of method 3. The method 900 may be performed by a WTRU / UE. At 902, the WTRU receives channel state information (CSI) reporting configuration information. The configuration information indicates (i) a plurality of matrices, (ii) a total number of rows and columns for each of the plurality of matrices, and (iii) an indication of reporting non-zero coefficients (NZC) useful for pre-decoder matrix information.

[0198] At 904, the WTRU receives one or more channel state information reference signals (CSI-RS).

[0199] At 906, the WTRU determines a precoding matrix indicator (PMI) based on channel measurements associated with one or more CSI-RSs. Here, the PMI includes, for each matrix in the plurality of matrices: (a) an indication of the total number of NZCs per row for all rows having NZCs in at least one and less than all columns of the matrix; and (b) an indication of a column index for each row of each row having NZCs in at least one and less than all columns of the matrix.

[0200] At 908, the WTRU may report the PMI to a network entity such as a gNB, a base station, or another WTRU.

[0201] In the method 900, the WTRU may determine the PMI using indications of the NZC for each column and each row. These indications may have binary values ​​of zero or one.

[0202] In method 900, the WTRU may determine the PMI by generating information where any indication in a row corresponds to a polarization of a beam and where any indication in a column corresponds to a DFT vector.

[0203] In method 900, the WTRU may report the PMI to the network entity such that the PMI is reported lacking an NZC value for any row having an all-zero coefficient indicator. Furthermore, such reporting may include reporting the PMI with a column index including an identification or position indication of a column in the row having an NZC value.

[0204] Reporting mode determination

[0205] In a first example, one or more reporting modes may be defined or used, and the WTRU may determine the reporting mode based on one or more of the following four options.

[0206] (1) The feedback overhead of method 1 can be determined by the number of beams L and K NZ Indicates the number of NZCs.

[0207] (2) The feedback overhead of method 2 may depend on the number of DFT vectors M v , and each DFT vector is related to j For j=1,…,M v Represents the number of NZCs and the number of beams L.

[0208] (3) The feedback overhead of method 3 depends on the number of DFT vectors M v , and each beam is associated with α l The number of NZCs and the number of beams L are represented for l=1,…,2L.

[0209] (4) Based on the corresponding combined feedback overhead, L and M v , K NZ , α j and α l Use a lookup table for different combinations of .

[0210] In a second example for reporting mode determination, the WTRU may receive a CSI reporting configuration. The configuration may include any of the following four configuration elements.

[0211] (1) The total number of DFT vectors of the W_2 matrix (eg, the number of columns in the W_2 matrix).

[0212] (2) The total number of beams (e.g., the number of rows in the W_2 matrix).

[0213] (3) The total number of component precoders of the PMI (eg, the total number of W_2 matrices in the PMI).

[0214] (4) Indication of a new reporting mode (eg, Method 1, Method 2, Method 3, or traditional method).

[0215] In a third example for reporting mode determination, the WTRU may use L, M v , K NZ , α j and α lDetermine the number of bits required to report the row and column positions of 1 in the W_2 matrix using Method 1 and / or Method 2 and / or Method 3. (a) In one example, the WTRU may create a 1, which may show the report as L, M v , K NZ , α j and α l (b) The WTRU may indicate its preference for Method 1, Method 2, Method 3, or the legacy method in the UCI.

[0216] In a fourth example for reporting mode determination, the WTRU may be explicitly indicated by the gNB what reporting CSI mode to use (e.g., Method 1, Method 2, Method 3, or legacy method). For example, higher layer configurations (e.g., SIB, RRC, and / or MAC-CE) may be used to indicate the reporting mode to be used per carrier, bandwidth part (BWP), CSI reporting configuration, and / or TRP. In another example, a dynamic indication (e.g., DCI) may be used to indicate the reporting mode to be used when a CSI report is triggered or for a CSI reporting instance at a future time.

[0217] Report mode indication

[0218] In one implementation, when the reporting mode is determined implicitly or autonomously, the WTRU may indicate or report the determined reporting mode. The determined CSI mode may be referred to as a reporting mode identifier (RMI) hereinafter. The WTRU may report the RMI based on one or more of the following two options.

[0219] (1) One or more uplink resources may be configured or used, and each uplink resource may be associated with a reporting mode.

[0220] (2) RMI may also be reported as part of CSI. RMI may be encoded separately from its associated CSI. Therefore, the receiver may first perform decoding of the RMI to determine the reporting type of the NZC index (e.g., combined report, beam DFT report, and / or DFT beam report), and perform decoding of its associated CSI. RMI may be jointly encoded with its associated CSI; the receiver may perform blind decoding on the RMI and its associated CSI.

[0221] Grouping and priority levels for CSI reporting

[0222] The payload size of the CSI report is limited. In order to adapt the payload size, the WTRU may prioritize reporting certain elements of the CSI report with higher priority and certain elements of the CSI report with lower priority. In Release 17, the different elements of the CSI report are divided into different groups. Then, for each group, the elements within the group are prioritized for reporting. Considering the reporting procedures disclosed above, the different elements of the CSI report can be divided into the following three groups.

[0223] Group 0: Indication for generating an oversampled DFT beam (i.e., DFT oversampling index i 1,1 = [q1q2] and the index i of the horizontal and vertical antenna elements on the panel 1,2 = [n1n2]) can be grouped into group 0. This group can also contain CMI / CFM / USM. This group can also contain subband amplitude threshold (SAT), which is discussed below. This group can also contain RMI. 1,8,l The index of the strongest amplitude coefficient on layer 1 identified may also be included in group 0. However, when joint reporting of subband amplitude coefficients is triggered as explained above, the indication of the index of the strongest amplitude coefficient (i.e., i 1,8,l ) can be excluded from group 0 and from the CSI report. This group can also contain all wideband amplitude coefficients, which are represented by i 2,3,l Identify for layer l (l=1,…,v), where v is the total number of layers.

[0224] Group 1: This group can contain the indicator i 1,5 and i 1,6 , both are used to identify M v When the WTRU chooses to report only wideband CSI based on CMI / CFM / USM, indicator i 1,5 and i 1,6 can be excluded from this group and can be excluded from CSI reports. This group can contain 2,4,l The subband amplitude coefficients identified by i 2,5,l The phase coefficient of the logo. 2,4,l and i 2,5,l Both, considering the higher feedback overhead associated with reporting of the NZC index, only LM v / 4 or even less number of main subband coefficients and phase coefficients may be marked as high priority and may be included in this group. Priority assignment may be done as in Release 17. In a similar manner, by i 1,7,l The L beams and M v The NZC indices on the DFT vectors are included in Group 1. 1,7,l Only LM related to the high priority subband and phase coefficients v / 4 or even less number of high priority elements may also be included in group 1.

[0225] Group 2: This group can contain i 1,7,l The remaining lowest priority element, i 2,4,l The remaining lowest priority elements of i 2,5,l The remaining lowest priority element of .

[0226] Based on the above grouping, for N CSI reports, the priority reporting levels may be represented as in Table 1. Hereinafter, priority 0 is referred to as the highest priority, priority 1 is referred to as the second highest priority, priority 2 is referred to as the third highest priority, and so on.

[0227]

[0228] Table 1. Priority levels for CSI reporting

[0229] Method for joint reporting of subband amplitude coefficients with reduced feedback overhead

[0230] In Release 17, L beams and M v The DFT vector is i 1,7,l The main subband amplitude coefficient index is represented by a length of 2LM v A bitmap indication of NZC index i is used, where bit 1 is used to indicate the index of the NZC index and bit 0 is used to indicate the index of the ZC index. In addition, in Release 17, 3 bits are used to report each quantized subband amplitude coefficient in the quantized subband amplitude coefficient. NZC index i 1,7,l The index of the corresponding phase coefficient may also be indicated. In Release 17, each quantized phase coefficient is indicated using 4 bits. Overall, this is an expensive reporting process in terms of feedback overhead. In the following, a method for jointly reporting the NZC index (i.e., i 1,7,l ) and a method for quantizing subband amplitude coefficients and subband phase coefficients. Then, following the proposed method, a priority reporting level for CSI reporting is proposed.

[0231] In an example for joint reporting, the WTRU may perform the following procedure.

[0232] The WTRU may report the K NZ The WTRU may use Units report K NZ .

[0233] The WTRU may convert K NZ The NZCs are grouped into d (1≤d≤g) groups, where g is the number of quantization levels (e.g., The ones bit is used to report the quantized subband amplitude coefficient). The grouping can be represented as [k1,k2,.......k d ], where k1 is the first group and k u (u=1,…,d) belongs to one of the g quantization levels as described in Table 2, where 1≤|k u |≤g and For a given g, the total number of possible quantization level combinations is the same as 2 g -1. For illustrative purposes, the grouping process can be explained using the following example. In Release 17, g=8 quantization levels are used so that each subband amplitude coefficient can be reported using 3 bits. To explain the working principle of the proposed method, all possible quantization level combinations for g=4 quantization levels are shown in Table 2.

[0234] Group Index Beam and DFT vector index combination <![CDATA[k1]]> [1],[2],[3],[4] <![CDATA[k2]]> [1,2],[1,3],[1,4],[2,3],[2,4],[3,4] <![CDATA[k3]]> [1,2,3],[1,2,4],[1,3,4],[2,3,4] <![CDATA[k4]]> [1,2,3,4]

[0235] Table 2. Illustrative examples of all possible quantization level combinations of subband amplitudes quantized using g=4 quantization levels

[0236] Following the above exemplary grouping for g=4 quantization levels, the WTRU may report the index of the group and the index of the combination of quantization levels within the group, which may be expressed using the length A bitmap report of the units digit.

[0237] Using two bitmaps of length b1 and b2, the WTRU may report the total number of NZCs and the indices of all NZC quantization levels. However, at this point, the WTRU has not yet reported the number of NZCs belonging to each of the quantization levels. The WTRU may report the number of NZCs belonging to each of the quantization levels using the following procedure. For illustrative purposes, such reporting is presented for g=4 quantization levels.

[0238] Reports the number of non-zero coefficients belonging to each quantization level

[0239] Group K u represents the u-th group, where u=1,…,g. The index of the group and the K NZ The combination of different quantization levels associated with the non-zero subband coefficients may be reported by the WTRU using b2 bits. In the illustrative example considered, k1=[1], which may be reported using b2 bits, indicates that all NZCK NZ The fact that it belongs to the first quantization level. Similarly, k1=[3] indicates that all NZCK NZThe fact that all NZCs belong to the third quantization level. The group index u=1 indicates the fact that all NZCs belong to one quantization level. Similarly, k2=[1,2] indicates the fact that some NZCs belong to the first quantization level and some NZCs belong to the second quantization level, while the group index u=2 indicates the fact that all NZCs belong to only two quantization levels. Similarly, k3=[1,3,4] indicates the fact that some NZCs belong to the first quantization level, some NZCs belong to the third quantization level and some NZCs belong to the fourth quantization level, while the group index u=3 indicates the fact that all NZCs belong to only three quantization levels. Similarly, k4=[1,2,3,4] indicates the fact that some NZCs belong to the first quantization level, some NZCs belong to the second quantization level, some NZCs belong to the third quantization level and some NZCs belong to the fourth quantization level, while the group index u=4 indicates the fact that the NZCs belong to four quantization levels. The WTRU may use b2 bits to report the group index and the number of quantization levels. The WTRU also needs to report the number of NZCs belonging to each quantization level. Such WTRU reporting for the illustrative example of g=4 quantization levels is explained as follows.

[0240] When k1=[1], k1=[2], k1=[3] or k1=[4]. The WTRU does not need to report the number of NZCs. Based on the group index u, the gNB may know all NZCs belonging to the (one) quantization level reported using b2 bits.

[0241] When k2 = [1,2], k2 = [1,3], k2 = [1,4], k2 = [2,3], k2 = [2,4], k2 = [3,4]. The possible number of NZCs that can belong to the highest quantization level is The WTRU may use The ones digit reports the number of NZCs belonging to the highest quantization level. And use b1 bits to report K NZ , the gNB can estimate the number of NZCs at a smaller quantization level.

[0242] When k3 = [1,2,3], k3 = [1,2,4], k3 = [1,3,4], k3 = [2,3,4]. The possible number of NZCs that can belong to the highest quantization level is The number of NZCs belonging to the highest quantization level that can be used by the WTRU The possible number of NZCs that can belong to the second highest quantization level is The number of NZCs belonging to the second highest quantization level may be used by the WTRU Since the WTRU can use b3=b 3,u +b 3,u-1 Individual report and and use b1 bits to report the total number K of NZCs NZ , so the WTRU may not need to report the number of NZCs at the minimum quantization level, because the gNB can estimate the number of NZCs at a smaller quantization level.

[0243] When k4 = [1, 2, 3, 4]. The possible number of NZCs that can belong to the highest quantization level is The number of NZCs belonging to the highest quantization level can be used by the WTRU bits to report. The possible number of NZCs that can belong to the second highest quantization level is The number of NZCs belonging to the second highest quantization level can be used by the WTRU bits to report. The possible number of NZCs that can belong to the third highest quantization level is The number of NZCs belonging to the third highest quantization level can be used by the WTRU bits to report. Since the WTRU can use b3 = b 3,u + b 3,u-1 + b 3,u-2 bits to report and and use b1 bits to report the total number K of NZCs by the WTRU NZ , so the WTRU may not need to report the number of NZCs at the minimum quantization level, because the gNB can estimate the number of NZCs at a smaller quantization level.

[0244] Using the exemplary procedures explained above, the WTRU can use a total of b = b2 + b3 bits to report the quantized subband amplitude coefficients of all K NZ NZCs. Since the number of NZCs belonging to the higher quantization levels is reported first, followed by the number of NZCs belonging to the second highest quantization level, etc., b3 can be quantized as In Release 17, b4 = 3(2K NZ - 1) bits are used to report the quantized subband amplitude coefficients. By comparing b4 with b1 + b2 + b3, it can be shown that the proposed method achieves a smaller feedback overhead compared to Release 17, especially for a higher number of NZCs.

[0245] To further reduce the feedback overhead, the WTRU can choose to report only the NZCs related to the higher quantization levels. Specifically, a threshold quantization level w such that 1 < w ≤ g. Then, the WTRU can choose to report only the NZCs whose related quantization levels are higher than w. In this case, the required size of b3 becomes where h is the number of NZCs at all quantization levels less than w. This procedure is explained above.

[0246] Following the above procedure, the WTRU reports the number of NZCs belonging to each quantization level. The WTRU also needs to report the index of each NZC on the beam and DFT vector. 1,7,l Indicates the length 2LM v The bitmap for L beams and M is described in detail above. v There are three methods for reporting NZC indices on DFT vectors. These methods can be used to report beam vector indices and DFT vector indices related to NZC.

[0247] Applicability of the proposed method to phase coefficient reporting

[0248] In Release 17, the WTRU reports the quantized sub-band phase coefficients using 4 bits. The proposed method for joint reporting of sub-band amplitude coefficients can be easily applied to report sub-band phase coefficients.

[0249] Applicability of the proposed method to broadband amplitude coefficient reporting

[0250] In Release 17, the WTRU reports the quantized wideband amplitude coefficient using 4 bits. The proposed method for joint reporting of sub-band amplitude coefficients can be easily applied to report wideband amplitude coefficients.

[0251] Priority rules for joint subband amplitude coefficient reporting method

[0252] Different quantized subband amplitude coefficients may be prioritized for reporting. Such prioritization may be performed based on the quantization level of the subband amplitude coefficients. The proposed method for jointly reporting subband amplitude coefficients is used below to develop priority reporting levels. The WTRU may choose to report subband amplitude coefficients with a higher quantization level and may choose not to report subband amplitude coefficients with a smaller quantization level. Such priority rules are explained using an illustrative example of g=4 quantization levels for quantizing subband amplitude coefficients. The same rules may be applied to other quantization levels.

[0253] For k1: (a) When k1 = [1], this means that all subband amplitude coefficients K NZ Using the lowest quantization level quantization, the WTRU may choose not to report all subband amplitude coefficients. (b) When k1 = [2], this means that all subband amplitude coefficients K NZ Using the second lowest quantization level, the WTRU may choose not to report all subband amplitude coefficients. (c) When k1 = [3], this means that all subband amplitude coefficients K NZUsing the second highest quantization level quantization, the WTRU may choose not to report or report all subband amplitude coefficients. (d) When k1=[4], this means that all subband amplitude coefficients K NZ Using the highest quantization level quantization, the WTRU may choose to report all sub-band amplitude coefficients.

[0254] For k2: (a) When k2∈[1,2], the WTRU may choose not to report some or all amplitude coefficients associated with [1], and the WTRU may choose not to report some or all amplitude coefficients associated with [2]. (b) When k2∈[1,3], the WTRU may choose not to report some or all amplitude coefficients associated with [1], and the WTRU may choose not to report some or all amplitude coefficients associated with [3]. (c) When k2∈[1,4], the WTRU may choose not to report some or all amplitude coefficients associated with [1], and the WTRU may choose to report all amplitude coefficients associated with [3]. (d) When k2∈[2,3], the WTRU may choose not to report some or all amplitude coefficients associated with [2], and the WTRU may choose not to report some or all amplitude coefficients associated with [3]. (e) When k2∈[2,4], the WTRU may choose not to report some or all amplitude coefficients associated with [2], and the WTRU may choose not to report some or all amplitude coefficients associated with [4]. (f) When k2∈[3,4], the WTRU may choose not to report some or all amplitude coefficients related to [3], and the WTRU may choose not to report some or all amplitude coefficients related to [4].

[0255] For k3: (a) When k3∈[1,2,3], the WTRU may choose not to report all amplitude coefficients associated with [1], the WTRU may choose not to report all coefficients associated with [2], and the WTRU may choose not to report some or all coefficients associated with [3]. (b) When k3∈[1,2,4], the WTRU may choose not to report all amplitude coefficients associated with [1], the WTRU may choose not to report all coefficients associated with [2], and the WTRU may choose to report all coefficients associated with [4]. (c) When k3∈[1,3,4], the WTRU may choose not to report all amplitude coefficients associated with [1], the WTRU may choose to report some coefficients associated with [3], and the WTRU may choose to report all coefficients associated with [4]. (d) When k3∈[2,3,4], the WTRU may choose not to report all amplitude coefficients associated with [2], the WTRU may choose to report some coefficients associated with [3], and the WTRU may choose to report all coefficients associated with [3].

[0256] For k4, (a) when k4 ∈ [1, 2, 3, 4], the WTRU may choose not to report all amplitude coefficients related to [1], the WTRU may choose not to report all amplitude coefficients related to [2], the WTRU may choose to report some coefficients related to [3], and the WTRU may choose to report all coefficients related to [4].

[0257] In an example embodiment, the WTRU may choose to report only NZCs whose quantization level is higher than w to reduce feedback.

[0258] Subband amplitude threshold determination

[0259] In a first example embodiment, one or more amplitude thresholds based on the quantization level of sub - band amplitude coefficients may be defined or used, and the WTRU may determine the sub - band amplitude threshold based on its associated quantization level and then choose to exclude all NZCs in the CSI report if their associated quantization level is below the threshold. For example, the WTRU may determine two thresholds (e.g., w1 and w2) such that 1 < w1 < w2 ≤ g. The WTRU may choose to exclude all NZCs whose quantization level is less than w1. The WTRU may choose to report only x out of z NZCs whose quantization level is between the thresholds w1 and w2. The thresholds w, w1, and w2 may be based on one or more of the following two characteristics.

[0260] (1) The level of the measured Doppler frequency. One or more Doppler frequency thresholds may be used, configured, or predetermined for w, w1, and w2; the sub - band amplitude threshold (SAT) may be determined if the measured Doppler frequency is within the threshold.

[0261] (2) The level of the frequency selectivity of the channel. For example, the WTRU may perform measurements of channel frequency selectivity, and the WTRU may determine the SAT based on the measured frequency selectivity. Frequency selectivity may be used interchangeably with delay spread, channel frequency coherence, and coherence bandwidth. One or more coherence bandwidth thresholds may be used, configured, or predetermined;

[0262] If the measured coherence bandwidth is within the threshold, the service area identifier (SAI) may be determined.

[0263] In a second example embodiment, the WTRU may be explicitly indicated by the gNB which SAT to use. For example, higher - layer configurations (e.g., SIB, RRC, and / or MAC - CE) may be used to indicate the SAT, bandwidth part (BWP), CSI report configuration, and / or TRP to be used per carrier. In another example, a dynamic indication (e.g., DCI) may be used to indicate the SAI.

[0264] Subband amplitude threshold indication

[0265] In one implementation, the WTRU may indicate or report the determined SAI when determined implicitly or autonomously. The WTRU may report the SAT based on one or more of the following.

[0266] One or more uplink resources may be configured or used, and each uplink resource may be associated with a SAT.

[0267] SAI may be reported as part of CSI. SAT may be encoded separately from its associated CSI. Therefore, the receiver may first perform decoding SAI. SAT may be jointly encoded with its associated CSI; the receiver may perform blind decoding for SAI and its associated CSI.

[0268] Applicability of the proposed method to phase coefficient reporting

[0269] The above priority reporting rules also apply to the reporting of phase coefficients.

[0270] Reports the time series of the pre-decoder

[0271] Reporting time series of pre-decoders in conventional systems

[0272] The pre-decoder structure for Release 16 / 17 is given as Where W1 represents the spatial domain basis, W2 is the common phase coefficient, and W f is the frequency domain compression matrix. In medium to high WTRU speed scenarios, the spatial domain and frequency domain basis (e.g., W1 and W f ) may remain constant over a short time period T. However, within the period T, the common phase coefficient (e.g., W2) may change at a faster rate. Therefore, the pre-decoder in the medium to high WTRU speed scenario can be expressed as Where t = t1, t2, ... In this context, the problem that arises is related to reporting the time series of the pre-decoder (e.g., W(t) or W2(t)) with less feedback overhead. In the following, a specific implementation of reporting the time series W(t) and / or W2(t) of the pre-decoder with less feedback overhead is disclosed.

[0273] First, the elements of Type II CSI reporting may be decomposed based on the Release-16 enhanced Type II (eType-II) codebook and the Release-17 further enhanced port selection Type II (FeType-II) codebook.

[0274] These elements can be set with a brief description as follows.

[0275]

[0276]

[0277] Table 3. Elements of Type II CSI reports with associated complexity in bits

[0278] The CSI elements listed in Table 3 are based on the Release 16e Type-II codebook. Release 17e Type-II has the same elements except i 1,2 In case of high / medium WTRU speed, the WTRU may need to report some of the above elements with less periodicity. Specifically, considering the fast changing channel due to medium / high speed, 1,7,l 、i 1,8,l 、i 2,3,l 、i 2,4,l and i 2,5,l The relevant CSI elements can be expected to change at a faster rate, which accounts for most of the feedback overhead of Type II CSI reporting. In the following, a method is proposed to report the CSI elements listed in Table 2 with less feedback overhead.

[0279] Report pre-decoder difference

[0280] describe

[0281] The W2 report constitutes the main weight of the CSI report. In order to report the content of W2 and / or W with less feedback overhead, the WTRU may choose to report the difference between two W2 and / or W reports. i and the past reporting interval t j The relative difference between the two pre-decoders at ) can be obtained as M_j=W(t i )-W(t j ), where i≠j and where j=1,…,i-1. Similarly, at two different time instances (e.g., t i and t j The difference of the pre-decoder at ) can also be expressed as M_j=W2(t i )-W2(t j ). At the first reporting interval (e.g., t1), the WTRU may choose to report the contents of W2(t1) and / or W(t1) in their original form. However, at the next reporting interval (e.g., t i , where i>1), the WTRU may choose to report W2(t i ) and / or the WTRU may choose to report W2(t i ) and W2(t j). The WTRU may determine the type of W2 and / or W report based on the following.

[0282] Report type determination

[0283] Let M(t i ) and M(t j ) is the non-zero quantized subband amplitude coefficient i 2,4,l , and / or two broadband amplitude coefficients i 2,3,l and / or respectively W2(t i ) and W2(t j ) of the phase coefficient i 2,5,l The vector M(t i ) and M(t j ) can also be expressed as W(t i ) and W(t j The quantized non-zero coefficients of M(t1) are assumed to be reported by the WTRU in reporting interval t_1, and now the WTRU wishes to report M(t i ).

[0284] M(t i ) and M(t j ) uses the same number of bits (e.g., γ) or a different number of bits (e.g., γ i and γ j )) quantized. The WTRU may report M(t i ) or you can choose to j =M(t i )-M(t j ) operation and then report the resulting non-zero coefficients. The WTRU may determine whether to report M(t i ) or report M based on j .

[0285] With reporting interval i (e.g., t i ), the WTRU can find M for all j=1,…,i-1 j =M(t i )-M(t j ). The WTRU may then determine M j The number of non-zero coefficients in (e.g., for all j ). The WTRU can then obtain the satisfied Since j = 1, ..., i-1, the selected index j can be used The units digit is reported. Therefore, if Where K NZ (t i) is W2(t i ), the WTRU may report the index j and M j On the other hand, when The WTRU may choose to report K NZ (t i ) non-zero amplitude / phase coefficients.

[0286] Report type indication

[0287] In each reporting interval, based on the above inequalities, the WTRU may choose to report the difference of the non-zero subband amplitude coefficients and / or phase coefficients, or the WTRU may choose to report the non-zero subband amplitude coefficients and phase coefficients in their original form. Specifically, in each reporting interval, the WTRU may choose to report both the non-zero subband amplitude coefficients and phase coefficients in their original form, or the WTRU may choose to report the difference of the subband amplitude coefficients and the non-zero phase coefficients in their original form (e.g., M j ), or the WTRU may choose to report the phase coefficients in their original form and the differences in the sub-band amplitude coefficients (ie, M j ), or the WTRU may choose to report the difference between the subband amplitude coefficient and the phase coefficient. The WTRU may use two bits in the UCI to indicate the type of report. The WTRU may explicitly indicate to the gNB which reporting type to use. For example, the WTRU may indicate the reporting mode, BWP, CSI reporting configuration and / or TRP to be used for each carrier. In an alternative solution, the WTRU may use one bit in the UCI to report the reporting type for the amplitude coefficient separately based on the determined reporting type. The WTRU may also use one bit in the UCI to report the reporting type for the phase coefficient separately based on the determined reporting type.

[0288] W1 and W f Periodic reporting of W2 and multiple and non-periodic reporting of W2

[0289] Due to the rapidly changing wireless channels at medium / high speeds, some parameters of the channel change much faster than other parameters. For example, channel gain and phase change at a much higher rate than path loss and shadowing. More specifically, the spatial domain (SD) basis W1 and the frequency domain (FD) basis W2 of the channel are f changes at a much smaller rate than the common phase coefficient W2. Therefore, the same rate as used to report W1 and W f It is reasonable to report W2 at a faster rate than the rate at which W2 is reported.

[0290] In one specific implementation, for each layer, W1 and W fPeriodic reports of W1 and aperiodic reports of W2. More specifically, in a particular implementation, a CSI report with a payload size x1 can be defined periodically with a period t1 to report W1, W2, and W f . The CSI report can also be used only to report W1 and W f . In this case, the payload size of the CSI report can be g1, where g1 < x1. The period t1 can be defined as a function of the Doppler and / or Doppler threshold and / or the change in the transmission of the TRS. For each period t1, N CSI reports each have a payload size y n (n = 1, …, N), where y n ≤ g1 < x1 can be defined to report multiple W2 co-phase coefficient matrices. The payload y n of each CSI report can be defined as a function of the Doppler or Doppler threshold and / or its correlation with past CSI reports. Multiple W2 coefficient matrices to be reported for fixed W1 and W f can be performed using N reports, where each report can be triggered aperiodically, and the periodicity between two reports can be defined as a function of the Doppler or Doppler threshold and / or its correlation with past reports. Moreover, the number N of CSI reports and the periodicity between two reports can be defined as a function of the Doppler and / or Doppler threshold or the correlation with past reports.

[0291] In a particular implementation, when reporting N periodic reports for fixed W1 and W f , the WTRU can report one, multiple, or different combinations of CSI elements indicated by i 1,7,l , i 1,8,l , i 2,3,l , i 2,4,l , and i 2,5,l . More specifically, the WTRU can report only p ≤ K h -1 i NZ phase coefficients per layer for 2,5,l the W2 report.

[0292] The WTRU can report only 0 ≤ p h ≤ K NZ -1 i 2,5,l phase coefficients per layer per report for 1 ≤ n ≤ N aperiodic W2 reports. The WTRU can also report along with 0 ≤ r p < N complex scaling vectors and report 0 ≤ p h ≤ K NZ -1 i 2,5,l phase coefficients per layer per report, where 1 ≤ δp ≤K NZ-1 For predicting phase coefficients for future reports.

[0293] The WTRU can report only 0 ≤ A per layer per report for W2 reports, where h ≤K NZ −1 i 2,4,l sub - band amplitude coefficients. The WTRU can also report, for W2 reports, together with 0 ≤ r h ≤ N complex vectors (where 1 ≤ δ a ≤K NZ-1 ) 0 ≤ A per layer per report h ≤K NZ −1 i 2,4,l sub - band amplitude coefficients for predicting phase coefficients for future reports.

[0294] The WTRU can report only the per - layer bitmap i for reports in the total report 1,7,l . When the WTRU selects to report only 0 ≤ A per layer for W2 reports, where h ≤K NZ −1 i 2,4,l sub - band amplitude coefficients, the WTRU can also report only for the h ≤K NZ −1 i 2,4,l associated reports for reporting i 1,7,l .

[0295] The WTRU can report only the per - layer per - report w ≤2 i h broadband amplitude coefficients for 2,3,l W2 reports. The WTRU can also report, for W2 reports, together with 0 ≤ r w ≤ N complex vectors (where 1 ≤ δ w ≤2) 0 ≤ A h ≤K NZ −1 i 2,4,l sub - band amplitude coefficients for predicting broadband amplitude coefficients for future reports.

[0296] The WTRU can report for Each W2 report reports only the strongest coefficients per layer 0≤s≤1. The WTRU may report the strongest coefficients by reporting their quantized values ​​and / or beam indices and / or DFT vector indices. As part of the Time Differential Carrier Phase (TDCP) report, the WTRU may provide the strongest coefficients for Each report has an indication of the common beam and the DFT vector index.

[0297] The WTRU may include information about the p-type measured by the TRS and / or CSI-RS as part of the TDCP report. h and / or and / or δ p and / or A h and / or and / or h and / or δ a and / or p and / or and / or and / or h and / or and / or δ w and / ors and / or instructions.

[0298] Strongest Beam Report

[0299] Reporting the strongest beam in a conventional system

[0300] Release 15, Type II / Type II port selection codebook: In Release 15, the wideband amplitude coefficient, subband amplitude coefficient, and associated phase coefficient on the strongest beam are given by and Indicates that, i 1,3,l ∈{0,1,…,2L}. In version 15, each broadband amplitude coefficient Using three bits for quantization, each subband amplitude coefficient One bit is used for quantization, and each phase coefficient c l,i You can use log2N PSK The digits are quantized, where N PSK ∈{4,8}. Report the amplitude and phase coefficients of each beam when N PSK = 4 requires six bits per layer and when N PSK = 8, seven bits are required per layer. In addition, in Release 15, L∈{2,3,4} beams per layer are supported. In Release 15, for each layer, the WTRU uses The ones digit reports the index i of the strongest beam 1,3,l Then, the gNB assumes and For L = 2, when NPSK = 4, resulting in a four-bit feedback overhead reduction per layer and when N PSK = 8, resulting in a five-bit feedback overhead reduction per layer. For L = 3 and L = 4, this is when N PSK = 4, resulting in a three-bit feedback overhead reduction per layer and when N PSK =8 results in a reduction of four bits of feedback overhead per layer.

[0301] Release 16 Enhanced Type II / Enhanced Type II Port Selection Codebook: In Release 16, the strongest wideband amplitude coefficient is given by The strongest subband amplitude coefficient is in and are the beam and DFT vector indices associated with the strongest wideband and subband amplitude coefficients, respectively, and where M v is the total number of DFT vectors used for frequency domain compression. The phase coefficients associated with the strongest wideband and subband amplitude coefficients are given by In version 16, each broadband amplitude coefficient Using four bits for quantization, each subband amplitude coefficient Three bits are used for quantization, and each phase coefficient c l,i,f Four bits are used for quantization. Therefore, eleven bits are required per beam to report the amplitude and phase coefficient values, and L∈{2,4,6} beams per layer are supported. In Release 16, the WTRU does not report the quantized amplitude and phase coefficient values ​​for the strongest beam. Instead, the WTRU may first remap the codebook index in such a way that after remapping, the index of the strongest amplitude coefficient is For example, instead of reporting quantized coefficient values ​​(i.e., and ), WTRU can use The ones digit reports only the strongest beam index (i.e. ). Then, the gNB can assume and This procedure results in a feedback overhead reduction of nine bits per layer when L=2, eight bits per layer when L=4, and seven bits per layer when L=6. The reduction in feedback overhead is achieved by the WTRU remapping the codebook index to ensure that f l * = 0. Specifically, for multiple reports of W_2 for fixed W_1 and W_f, this procedure may impose a huge burden of remapping complexity on the WTRU.

[0302] Release 17 further enhances the Type II port selection codebook: In Release 17, similar to Release 16, Each wideband amplitude coefficient represented by is quantized using four bits, given by Each subband amplitude coefficient represented is quantized using three bits, and each phase coefficient c l,i,f Four bits are used for quantization. The number of antenna ports selected is K1 = αP CSI-RS , where P CSI-RS is the given number of antenna ports, L = K1 / 2 is the number of beams, M and α are frequency domain compression parameters, and the index of the strongest beam on a layer is i * ∈0,1,…,K1-1. In version 17, the strongest coefficient and related The quantized value of is not reported. Instead, after the WTRU remaps the codebook index, The ones digit reports only the index The index of the strongest amplitude coefficient is When observing Table 3, it can be concluded that the strongest beam index reporting results in a feedback overhead reduction of up to 9 bits.

[0303] Issues with Strongest Beam Index reporting

[0304] In Release 16 / 17, in order to report the strongest beam, the gNB needs to know the beam index and the DFT vector index f l * The WTRU only reports To avoid reporting l * , the WTRU remaps the codebook index in such a way that f l * = 0. This remapping results in reduced feedback overhead, but at the expense of WTRU complexity. Release 18 MIMO work aims to enhance CSI for high / medium WTRU speeds, where multiple W2 are used for fixed W1 and W f In this case, the WTRU will need to report for fixed W1 and W f The codebook index is remapped multiple times, which places a huge computational burden on the WTRU.

[0305] Strongest Coefficient Report

[0306] In a solution that enables the WTRU to avoid the computational complexity of remapping the codebook index when reporting the strongest coefficient on each layer l, the WTRU may perform one or more of the following five actions.

[0307] (1) The WTRU may not remap the codebook index and / or DFT vector index to ensure that f l * =0; (2) WTRU may not report the strongest beam index and / or the associated DFT vector index (f l * ); (3) The WTRU may not report the amplitude coefficient (4) The WTRU may not report the phase combining coefficients and / or (5) the WTRU may report the subband amplitude coefficients The quantified value of .

[0308] By observing the reported quantized subband amplitude coefficients on layer l (e.g., ), the beam index with the strongest coefficient can be obtained according to (1) and the DFT vector index f with the strongest coefficient l * :

[0309]

[0310] Since the reported subband amplitude coefficients is quantized, so there may be multiple combinations of i,f that satisfy (1). In this case, and and / or and max(f l * ), and / or second and second and / or third and the third max(f l * ) and so on can be classified into beams and DFT vector indices with the strongest amplitude coefficients.

[0311] In an alternative solution that enables the WTRU to avoid the computational complexity of remapping the codebook index when reporting the strongest coefficient on each layer l, the WTRU may perform one or more of the following six actions. (1) The WTRU may not remap the codebook index and / or DFT vector index to ensure that f l * =0; (2) WTRU may not report the strongest beam index and / or the associated DFT vector index (3) The WTRU may not report the phase combining coefficients (4) The WTRU may not report the subband amplitude coefficients quantized value; (5) WTRU can report the wideband amplitude coefficient and / or (6) the WTRU may report The index of the DFT vector concerned.

[0312] By observing the reported quantized broadband amplitude coefficients on layer l (e.g., ), the beam index with the strongest coefficient can be obtained according to the following formula:

[0313]

[0314] In an alternative implementation that enables the WTRU to avoid the computational complexity of remapping the codebook index when reporting the strongest coefficient on each layer l, the WTRU may perform one or more of the following six actions. (1) The WTRU may not remap the codebook index and / or DFT vector index to ensure that f l * =0; (2) WTRU may report the strongest beam index (3) The WTRU may report the associated DFT vector index f l * ; (4) WTRU may not report the amplitude coefficient (5) The WTRU may not report the phase combining coefficients and / or (6) the WTRU may not report the subband amplitude coefficients The quantified value of .

[0315] Index received at gNB and f l * When the broadband amplitude coefficient can be set to a maximum value. Similarly, the subband amplitude coefficient can be set to a maximum value. Finally, the phase combination coefficient Can be set to zero.

[0316] In one embodiment, a method implemented in a WTRU includes sampling a wireless channel at a rate for capturing a Doppler effect on the wireless channel. The WTRU measures CSI of the wireless channel based on at least one configured channel state information reference signal (CSI-RS).

[0317] The WTRU estimates the trend of the channel variation based on the captured Doppler effect. The CSI of the wireless channel is corrected by the WTRU based on the estimated trend of the channel variation. The WTRU then sends a CSI measurement report based on the corrected CSI of the wireless channel.

[0318] In one embodiment, a method performed by a WTRU to reduce the overhead of reporting precoding matrices includes receiving a configuration for CSI reporting to a BS. The configuration includes a plurality of matrices to be reported to the BS, each matrix including an indication of non-zero coefficients (NZC) occurring in an arrangement of columns and rows.

[0319] The WTRU receives one or more CSI-RS used to measure the channel used for CSI reporting and determines an indication of the NZC for each matrix based on the channel measurement.

[0320] The WTRU reports an indication of the NZCs for each matrix to the BS using an indicator for each of the NZCs that appear in the columns and rows of each matrix, wherein the report for each column in the matrix includes: (a) an indication of the total number of NZCs in the corresponding column of the matrix, and (b) an indication of the rows in which the NZCs appear in the corresponding column. In this method, all columns in the matrix that have at least one NZC and that have a number of NZCs that is less than the number of rows are reported, and all NZC occurrences are reported to the BS for each matrix in the plurality of matrices.

[0321] In one embodiment, a method performed by a WTRU to reduce the overhead of reporting precoding matrices includes receiving a configuration for CSI reporting to a BS. The configuration includes a plurality of matrices to be reported to the BS, each matrix including an indication of non-zero coefficients (NZC) occurring in an arrangement of rows and columns.

[0322] The WTRU receives one or more CSI-RS used to measure the channel used for CSI reporting and determines an indication of the NZC for each matrix based on the channel measurement.

[0323] The WTRU reports an indication of the NZCs for each matrix to the BS using an indicator for each of the NZCs that appear in the rows and columns of each matrix, wherein the report for each row in the matrix includes: (a) an indication of the total number of NZCs in the corresponding row of the matrix, and (b) an indication of the columns in which the NZCs appear in the corresponding row. In this method, all rows in the matrix that have at least one NZC and that have a number of NZCs that is less than the number of columns are reported, and all NZC occurrences are reported to the BS for each of the plurality of matrices.

[0324] in conclusion

[0325] Although features and elements are provided above in specific combinations, it will be understood by those of ordinary skill in the art that each feature or element may be used alone or in any combination with other features and elements. The present disclosure is not limited to the specific embodiments described in this patent application, which are intended to be illustrative of various aspects. Many modifications and variations can be made without departing from the essence and scope of the present invention, as they will be apparent to those skilled in the art. Unless explicitly provided as such, any element, action or description used in the present application specification should not be understood as being essential or necessary to the present invention. According to the foregoing description, in addition to those listed herein, functionally equivalent methods and devices within the scope of the present disclosure will be apparent to those skilled in the art. Such modifications and variations are intended to fall within the scope of the appended claims. The present disclosure is limited only to the terms of the appended claims and the full range of equivalent forms of such entitled claims. It should be understood that the present disclosure is not limited to a specific method or system.

[0326] For simplicity, the foregoing embodiments are discussed with reference to the terminology and structure of infrared capable devices (i.e., infrared transmitters and receivers). However, the embodiments discussed are not limited to these systems, but can be applied to other systems using other forms of electromagnetic waves or non-electromagnetic waves (such as sound waves).

[0327] It should also be understood that the terms used herein are for the purpose of describing specific embodiments only and are not intended to be limiting. As used herein, the term "video" or the term "image" may mean any of a snapshot, a single image, and / or a plurality of images displayed on a temporal basis. For example, when referred to herein, the term "user equipment" and its abbreviation "UE", the term "remote" and / or the term "head-mounted display" or its abbreviation "HMD" may mean or include (i) a wireless transmit and / or receive unit (WTRU); (ii) any of a plurality of embodiments of the WTRU; (iii) a wireless and / or wired (e.g., tetherable) device configured with (in particular) some or all of the structure and functionality of the WTRU; (iii) a wireless and / or wired device configured with less than all of the structure and functionality of the WTRU; or (iv), etc. This document is relative to Figures 1A to 1D Details of an example WTRU are provided that may represent any WTRU described herein. As another example, various disclosed embodiments herein above and below are described as utilizing a head mounted display. Those skilled in the art will recognize that devices other than head mounted displays may be utilized and that some or all of the embodiments of the present disclosure and various disclosed embodiments may be modified accordingly without undue experimentation. Examples of such other devices may include drones or other devices configured to stream information to provide an adapted reality experience.

[0328] In addition, the methods provided herein may be implemented in a computer program, software, or firmware incorporated into a computer-readable medium for execution by a computer or processor. Examples of computer-readable media include electronic signals (sent via a wired or wireless connection) and computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, read-only memory (ROM), random access memory (RAM), registers, cache memory, semiconductor memory devices, magnetic media (such as built-in hard disks and removable disks), magneto-optical media, and optical media (such as CD-ROM disks and digital versatile disks (DVDs)). A processor associated with the software may be used to implement a radio frequency transceiver for a WTRU, UE, terminal, base station, RNC, MME, EPC, AMF, or any host computer.

[0329] Variations of the methods, devices, and systems provided above are possible without departing from the scope of the present invention. In view of the various embodiments that may be applied, it should be understood that the illustrated embodiments are merely examples and should not be considered to limit the scope of the following claims. For example, the embodiments provided herein include handheld devices that may include or be used with any suitable voltage source (such as a battery, etc.) that provides any suitable voltage.

[0330] In addition, in the embodiment provided above, processing platform, computing system, controller and other equipment including processor are pointed out.These equipment may include at least one central processing unit ("CPU") and memory.According to the practice of the technician in the field of computer programming, the reference to the symbolic representation of action and operation or instruction can be performed by various CPUs and memories.Such action and operation or instruction can be referred to as "executed", "computer executed" or "CPU executed".

[0331] Those of ordinary skill in the art will appreciate that the actions and symbolic representations of operations or instructions include manipulation of electrical signals by the CPU. The electrical system represents data bits that may result in the ultimate transformation of electrical signals or reduction of electrical signals and the retention of data bits at memory locations in the memory system, thereby reconfiguring or otherwise changing the operation of the CPU and performing other processing of signals. The memory location that holds the data bits is a physical location that has specific electrical, magnetic, optical, or organic properties that correspond to or represent the data bits. It should be understood that the embodiments are not limited to the above-mentioned platforms or CPUs, and other platforms and CPUs may also support the provided methods.

[0332] The data bits may also be maintained on a computer-readable medium, including magnetic disks, optical disks, and any other volatile (e.g., random access memory ("RAM")) or non-volatile (e.g., read-only memory ("ROM")) mass storage system readable by a CPU. The computer-readable medium may include cooperating or interconnected computer-readable media that reside solely on a processing system or distributed across multiple interconnected processing systems that may be local or remote relative to the processing system. It should be understood that the embodiments are not limited to the above-mentioned memories, and other platforms and memories may also support the provided methods.

[0333] In an exemplary embodiment, any of the operations, processes, etc. described herein may be implemented as computer-readable instructions stored on a computer-readable medium. The computer-readable instructions may be executed by a processor of a mobile unit, a network element, and / or any other computing device.

[0334] There is little difference between hardware implementation and software implementation of various aspects of the system. The use of hardware or software is usually (but not always, because in some contexts, the choice between hardware and software may become important) a design choice that represents a trade-off between cost and efficiency. There may be various media (e.g., hardware, software, and / or firmware) that can implement the processes and / or systems and / or other technologies described herein, and the preferred media may vary with the context of the deployment process and / or system and / or other technologies. For example, if the implementer determines that speed and accuracy are most important, the implementer may choose a media that is primarily hardware and / or firmware. If flexibility is most important, the implementer may choose a specific implementation that is primarily software. Alternatively, the implementer may choose some combination of hardware, software, and / or firmware.

[0335] The above detailed description has listed various embodiments of the device and / or process by using block diagrams, flow charts and / or examples. In the case where such block diagrams, flow charts and / or examples include one or more functions and / or operations, it should be understood by those skilled in the art that each function and / or operation within such block diagrams, flow charts or examples can be implemented individually and / or collectively by a wide range of hardware, software, firmware or almost any combination thereof. In one embodiment, several parts of the subject matter described herein can be implemented via application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), digital signal processors (DSPs) and / or other integrated formats. However, those skilled in the art will recognize that some aspects of the embodiments disclosed herein can be equivalently implemented in integrated circuits as a whole or in part as one or more computer programs running on one or more computers (e.g., one or more programs running on one or more computer systems), one or more programs running on one or more processors (e.g., one or more programs running on one or more microprocessors), firmware or almost any combination thereof, and according to the present disclosure, designing circuits and / or writing software and / or firmware codes will be completely within the technical scope of those skilled in the art. Furthermore, those skilled in the art will appreciate that the mechanisms of the subject matter described herein can be distributed as a program product in a variety of forms, and that the illustrative embodiments of the subject matter described herein apply regardless of the specific type of signal-bearing medium used to actually perform the distribution. Examples of signal-bearing media include, but are not limited to, the following: recordable type media (such as floppy disks, hard drives, CDs, DVDs, digital tapes, computer memory, etc.); and transmission type media (such as digital and / or analog communication media (e.g., fiber optic cables, waveguides, wired communication links, wireless communication links, etc.)).

[0336] Those skilled in the art will recognize that it is common in the art to describe devices and / or processes in the manner set forth herein, and thereafter use engineering practices to integrate such described devices and / or processes into a data processing system. That is, at least a portion of the devices and / or processes described herein can be integrated into a data processing system via a reasonable amount of experimentation. Those skilled in the art will recognize that a typical data processing system generally may include one or more of the following: a system unit housing; a video display device; a memory, such as a volatile memory and a non-volatile memory; a processor, such as a microprocessor and a digital signal processor; a computing entity, such as an operating system, a driver, a graphical user interface, and an application; one or more interactive devices, such as a touch pad or a screen; and / or a control system, including a feedback loop and a control motor (e.g., a feedback for sensing position and / or velocity, a control motor for moving and / or adjusting components and / or quantities). A typical data processing system can be implemented using any suitable commercially available components, such as those typically found in data computing / communication and / or network computing / communication systems.

[0337] The subject matter described herein sometimes illustrates different components included in or connected to different other components. It should be understood that such depicted architectures are merely examples, and in fact many other architectures that achieve the same function can be implemented. In a conceptual sense, any arrangement of components that achieve the same function is effectively "associated" so that the desired function can be achieved. Therefore, any two components that are combined to achieve a specific functionality in this article can be considered to be "associated" with each other so that the desired functionality is achieved, regardless of the architecture or intermediate components. Similarly, any two components so associated can also be considered to be "operably connected" or "operably coupled" to each other to achieve the desired function, and any two components that can be so associated can also be considered to be "operably coupled" to each other to achieve the desired function. Specific examples of operable coupling include, but are not limited to, components that can physically cooperate and / or physically interact and / or components that can wirelessly interact and / or wirelessly interact and / or components that can logically interact and / or components that can logically interact.

[0338] With respect to substantially any plural and / or singular terms used herein, those skilled in the art may translate from the plural to the singular and / or from the singular to the plural as appropriate, as appropriate to the context and / or application. For clarity, various singular / plural arrangements may be explicitly listed herein.

[0339] Those skilled in the art will understand that, in general, the terms used herein and in particular in the appended claims (e.g., the bodies of the appended claims) are generally intended to be “open-ended” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “comprising” should be interpreted as “including but not limited to, etc.”) and / or “permissive” terms (e.g., the term “is” can be interpreted as “can” and / or “may,” the term “refers to” can be interpreted as “can refer to” and / or “may refer to,” the term “receive” can be interpreted as “can receive” and / or “may receive,” the term “supports” can be interpreted as “can support” and / or “may support,” the term “interface” can be interpreted as “can interface with” and / or “may interface with”). , the term "send" may be interpreted as "can dock" and / or "may dock", "can send" and / or "may send", the term "transmit" may be interpreted as "can transmit" and / or "may transmit", the term "do not refer" (etc.) may be interpreted as "may not refer" and / or "may not refer", the term "do not receive" (etc.) may be interpreted as "may not receive" and / or "may not receive", the term "do not support" (etc.) may be interpreted as "may not support" and / or "may not support", the term "do not dock" (etc.) may be interpreted as "may not dock" and / or "may not dock", the term "do not send" (etc.) may be interpreted as "may not send" and / or "may not send", the term "do not transmit" (etc.) may be interpreted as "may not transmit" and / or "may not transmit", etc.). It should also be understood by those skilled in the art that if a specific number of introduced claim narrative objects is intended, such intent will be explicitly stated in the claim, and in the absence of such narrative objects, there is no such intent. For example, where only one item is intended, the term "single" or similar language may be used. To aid understanding, the following appended claims and / or the description herein may include the use of the introductory phrases "at least one" and "one or more" to introduce claim recitations. However, the use of such phrases should not be construed as implying that any particular claim including such introduced claim recitations is limited to embodiments including only one such recitation by the indefinite article "a" or "an" to introduce the claim recitation, even when the same claim includes the introductory phrases "one or more" or "at least one" and an indefinite article such as "a" or "an" (e.g., "a" and / or "an" should be interpreted as meaning "at least one" or "one or more"). The same applies to the use of definite articles used to introduce claim recitations.Furthermore, even if a specific number of an introduced claim recitation is explicitly recited, one skilled in the art will recognize that such recitation should be interpreted to mean at least the recited number (e.g., a bare recitation of "two recitations" without other modifiers means at least two recitations or two or more recitations). Additionally, in those instances where a convention similar to "at least one of A, B, and C, etc." is used, generally speaking, the meaning of such construction is that one skilled in the art would understand the convention (e.g., "a system having at least one of A, B, and C" would include, but is not limited to, a system having A alone, B alone, C alone, A and B together, A and C together, B and C together, and / or A, B, and C together, etc.). In those instances where a convention similar to "at least one of A, B, or C, etc." is used, generally speaking, the meaning of such construction is that one skilled in the art will understand the convention (e.g., "a system having at least one of A, B, or C" will include, but is not limited to, systems having A alone, B alone, C alone, A and B at the same time, A and C at the same time, B and C at the same time, and / or A, B, and C at the same time, etc.). One skilled in the art will also understand that, in fact, any separate word and / or phrase presenting two or more alternative terms, whether in the specification, claims, or drawings, should be understood to contemplate the possibility of including one of the terms, any of the terms, or both of the terms. For example, the phrase "A or B" will be understood to include the possibility of "A" or "B" or "A and B". In addition, as used herein, the term "any of..." followed by a listing of multiple items and / or multiple categories of items is intended to include "any of," "any combination," "any multiples," and / or "any combination of multiples" of the items and / or categories of items, either alone or in combination with other items and / or other categories of items. Furthermore, as used herein, the term "set" is intended to include any number of items, including zero. Additionally, as used herein, the term "number" is intended to include any number, including zero. And, as used herein, the term "plurality" is intended to be synonymous with "multiple."

[0340] In addition, where features or aspects of the disclosure are described in terms of Markush groups, those skilled in the art will recognize that the disclosure is also described in terms of any individual member or subgroup of members of the Markush group.

[0341] As will be understood by those skilled in the art, for any and all purposes (such as in terms of providing a written description), all ranges disclosed herein also encompass any and all possible sub-ranges and combinations of their sub-ranges. Any listed range can be easily identified as fully describing and enabling the same range to be divided into at least equal halves, one-third, one-quarter, one-fifth, one-tenth, etc. As a non-limiting example, each range discussed herein can be easily divided into a lower third, a middle third, and an upper third, etc. As will be understood by those skilled in the art, all languages ​​such as "up to", "at least", "greater than", "less than", etc. include the cited numbers and refer to the ranges that can be subsequently divided into sub-ranges as described above. Finally, as will be understood by those skilled in the art, the range includes each individual number. Therefore, for example, a group with 1 to 3 units refers to a group with 1, 2 or 3 units. Similarly, a group with 1 to 5 units refers to a group with 1, 2, 3, 4 or 5 units, etc.

[0342] Furthermore, the claims should not be read as limited to the order or elements presented unless otherwise stated. Furthermore, the use of the term "means for..." in any claim is intended to invoke 35 USC § 112, or means-plus-function claim format, and any claim without the term "means for..." is not intended to be so.

[0343] Suitable processors include, by way of example, 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, an application specific integrated circuit (ASIC), an application specific standard product (ASSP), a field programmable gate array (FPGA) circuit, any other type of integrated circuit (IC), and / or state machine.

[0344] The WTRU may be used in conjunction with a module, which may be implemented in hardware and / or software including: software defined radio (SDR) and other components such as a camera, a video camera module, a videophone, a speakerphone, a vibration device, a speaker, a microphone, a television transceiver, a hands-free headset, a keyboard, module, a frequency modulation (FM) radio unit, a near field communication (NFC) module, a liquid crystal display (LCD) display unit, an organic light emitting diode (OLED) display unit, a digital music player, a media player, a video game player module, an internet browser, and / or any wireless local area network (WLAN) or ultra-wideband (UWB) module.

[0345] Although various embodiments have been described in terms of a communication system, it is contemplated that the system may be implemented in software on a microprocessor / general purpose computer (not shown). In certain embodiments, one or more of the functions of the various components may be implemented in software controlling a general purpose computer.

[0346] Furthermore, while the invention has been illustrated and described herein with reference to specific embodiments, the invention is not intended to be limited to the details shown. Rather, various modifications may be made to the details within the scope and range of equivalents of the claims without departing from the invention.

Claims

1. A wireless transmit / receive unit (WTRU) comprising circuitry, the WTRU comprising a receiver, a transmitter, a processor, and a memory, wherein: The receiver is configured to: receiving channel state information (CSI) reporting configuration information indicating (i) a plurality of matrices, (ii) a total number of rows and columns for each of the plurality of matrices, and (iii) an indication to report non-zero coefficients (NZC); receiving one or more channel state information reference signals (CSI-RS); The processor is configured to: Determining a precoding matrix indicator (PMI) based on a channel measurement associated with the one or more CSI-RSs, wherein for each matrix in the plurality of matrices, the PMI comprises: (a) an indication of the total number of NZCs per column for all columns having NZCs in at least one and less than all rows of said matrix, and (b) an indication of a row index for each of said columns having NZC in at least one and less than all rows of said matrix; and The transmitter is configured as: The PMI stated in the report.

2. The WTRU of claim 1 , wherein the processor determines the PMI by determining an indication of the NZC for each column and each row, wherein the determined indication is either zero or one.

3. The WTRU of claim 1 , wherein the received CSI report configuration information includes information that any of the indications in a row corresponds to a polarization of a beam and any of the indications in a column corresponds to a DFT vector.

4. The WTRU of claim 1 , wherein the reported PMI lacks an NZC value for any column having an all-zero coefficient indicator.

5. The WTRU of claim 1 , wherein the indication of a row index for each column comprises an identification or position indication of a row having an NZC value in the column.

6. A method performed by a wireless transmit / receive unit (WTRU), the method comprising: receiving channel state information (CSI) reporting configuration information indicating (i) a plurality of matrices, (ii) a total number of rows and columns for each of the plurality of matrices, and (iii) an indication to report non-zero coefficients (NZC); receiving one or more channel state information reference signals (CSI-RS); Determining a precoding matrix indicator (PMI) based on a channel measurement associated with the one or more CSI-RSs, wherein for each matrix in the plurality of matrices, the PMI comprises: (a) an indication of the total number of NZCs per column for all columns having NZCs in at least one and less than all rows of said matrix, and (b) an indication of a row index for each of the columns having the NZC in at least one and less than all rows of the matrix; as well as The PMI is reported to a network entity. 7 . The method of claim 6 , wherein determining the PMI comprises determining the PMI using an indication of the NZC for each column and each row, wherein the indication has a binary value of zero or one.

8. The method of claim 6, wherein determining the PMI comprises generating information that any indication in a row corresponds to a polarization of a beam and any indication in a column corresponds to a DFT vector.

9. The method of claim 6, wherein reporting the PMI to a network entity comprises reporting the PMI lacking an NZC value for any column having an all-zero coefficient indicator.

10. The method of claim 6, wherein reporting the PMI to a network entity comprises reporting the PMI with a row index, the row index comprising an identification or location indication of a row in a column having an NZC value.

11. A wireless transmit / receive unit (WTRU) comprising circuitry, the WTRU comprising a receiver, a transmitter, a processor, and a memory, wherein: The receiver is configured to: receiving channel state information (CSI) reporting configuration information indicating (i) a plurality of matrices, (ii) a total number of rows and columns for each of the plurality of matrices, and (iii) an indication to report non-zero coefficients (NZC); receiving one or more channel state information reference signals (CSI-RS); The processor is configured to: Determining a precoding matrix indicator (PMI) based on a channel measurement associated with the one or more CSI-RSs, wherein for each matrix in the plurality of matrices, the PMI comprises: (a) an indication of the total number of NZCs per row for all rows having NZCs in at least one and less than all rows of said matrix, and (b) an indication of a column index for each of said rows having said NZC in at least one and less than all columns of said matrix; and The transmitter is configured as: The PMI stated in the report.

12. The WTRU of claim 11, wherein the processor determines the PMI by determining an indication of the NZC for each column and each row, wherein the determined indication is either zero or one.

13. The WTRU of claim 11, wherein the received CSI report configuration information includes information that any of the indications in the columns corresponds to a polarization of a beam and any of the indications in the rows corresponds to a DFT vector.

14. The WTRU of claim 11, wherein the reported PMI lacks an NZC value for any row having an all-zero coefficient indicator.

15. The WTRU of claim 11, wherein the indication of a column index for each row comprises an identification or location indication of a column having an NZC value in the row.

16. A method performed by a wireless transmit / receive unit (WTRU), the method comprising: receiving channel state information (CSI) reporting configuration information indicating (i) a plurality of matrices, (ii) a total number of rows and columns for each of the plurality of matrices, and (iii) an indication to report non-zero coefficients (NZC); receiving one or more channel state information reference signals (CSI-RS); Determining a precoding matrix indicator (PMI) based on a channel measurement associated with the one or more CSI-RSs, wherein for each matrix in the plurality of matrices, the PMI comprises: (a) an indication of the total number of NZCs per row for all rows having NZCs in at least one and less than all columns of said matrix, and (b) an indication of a column index for each of the rows having the NZC in at least one and less than all columns of the matrix; as well as The PMI is reported to a network entity.

17. The method of claim 16, wherein determining the PMI comprises determining the PMI using an indication of the NZC for each column and each row, wherein the indication has a binary value of zero or one.

18. The method of claim 16, wherein determining the PMI comprises generating information that any indication in a column corresponds to a polarization of a beam and any indication in a row corresponds to a DFT vector.

19. The method of claim 16, wherein reporting the PMI to a network entity comprises reporting the PMI lacking an NZC value for any row having an all-zero coefficient indicator.

20. A computer readable storage medium having instructions thereon which, when executed, perform the method of any one of claims 6 to 10 or the method of any one of claims 16 to 19.

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