Data-driven WTRU-specific MIMO precoder codebook design

Abstract

Systems, methods, and means for a data-driven wireless transmit-receive unit (WTRU) specific MIMO precoder codebook are disclosed herein. Quality of service (e.g., BER) may be improved, for example, using a precoder for a data transmission, where the precoder is selected from a codebook constructed from observed data. A wireless transmit / receive unit (WTRU) may construct (e.g., with a base station) a codebook based on observed data (e.g., time-varying channel conditions) including a precoder to use for a data transmission. The WTRU may determine the codebook, for example, using a precoder prediction model (e.g., using machine learning and / or artificial intelligence).

Description

Technical Field

[0001] (Cross - reference to Related Applications) This application claims the benefit of U.S. Provisional Application No. 63 / 253,682, filed on October 8, 2021, the contents of which are hereby incorporated by reference in their entirety.

Background Art

[0002] Mobile communication using wireless communication has been continuously evolving. The fifth generation of mobile communication radio access technology (RAT) can be referred to as the new radio (NR) of 5G. Previous (conventional) generations of mobile communication RAT can be, for example, the fourth - generation (4G) long - term evolution (LTE). A wireless communication device can establish communication with other devices and data networks via an access network such as a radio access network (RAN).

Summary of the Invention

[0003] Systems, methods, and means for a data - driven MIMO precoder codebook specific to a wireless transmit - receive unit (WTRU) are disclosed herein. Quality of service (e.g., BER) may be improved, for example, by using a precoder for data transmission, and the precoder is selected from a codebook constructed from observed data. A wireless transmit / receive unit (WTRU) may construct a codebook (e.g., with a base station) based on observed data (e.g., time - varying channel conditions) including a precoder used for data transmission. The WTRU may determine the codebook, for example, using a precoder prediction model (e.g., using machine learning and / or artificial intelligence).

[0004] The WTRU may construct a codebook (e.g., with a base station) based on observed data using a precoder prediction model. The WTRU may include a processor. The WTRU may determine precoder spatial selection information. The precoder spatial selection information may include WTRU-specific precoder action spatial information. The WTRU may determine precoder spatial selection information from a base station (e.g., the WTRU may establish precoder spatial selection information by transmitting a reference signal to the base station). The WTRU may receive first channel state information from the base station (e.g., in a channel state information reference signal (CSI-RS)). The WTRU may select a first precoder from WTRU-specific precoder action spatial information. The WTRU may determine a first reward value for the first precoder (e.g., using a precoder prediction model). The first reward value may be associated with a first CSI-RS. The WTRU may determine, for example, whether the precoder prediction model has converged (e.g., whether the conditions are met) based on a first reward value. If the precoder prediction model has converged, the WTRU may indicate to the base station that the model has converged, as well as the precoder and reward values ​​associated with the convergence.

[0005] The WTRU may determine, based on the first reward value, that the precoder prediction model has not converged. The WTRU may select a second precoder from the precoder spatial selection information. The WTRU may determine a second reward value for the second precoder. The WTRU may continue to select precoders and determine their associated reward values ​​to determine model convergence, for example, until the model converges or until several iterations have passed.

[0006] The WTRU may receive a second CSI-RS from the base station (for example, after the model has converged). The WTRU may use the second CSI-RS and the precoder prediction model to determine the predicted precoder. The WTRU may generate a codebook using the precoder used to determine model convergence and the predicted precoder.

[0007] The WTRU may include a processor configured to perform several actions. A sound reference signal (SRS) may be transmitted to the network. Precoder spatial selection information may be received from the network. A data transmission and channel status information reference signal (CSI-RS) may be received from the network. A reward value may be calculated and provided to the precoder predictor model along with the CSI-RS as input for acquiring precoders. The acquired precoders may be transmitted to the network. The precoder predictor model may be determined to be converged. A set of precoders may be requested from the network. A set of precoders may be received from the network, and an acceptance notification signal may be transmitted to the network. [Brief explanation of the drawing]

[0008] [Figure 1A] This is a system diagram illustrating an exemplary communication system in which one or more disclosed embodiments may be implemented. [Figure 1B] This is a system diagram illustrating an exemplary wireless transmit / receive unit (WTRU) that may be used in a communication system illustrated in Figure 1A, according to one embodiment. [Figure 1C] This is a system diagram illustrating an exemplary radio access network (RAN) and an exemplary core network (CN) that may be used in a communication system illustrated in Figure 1A according to one embodiment. [Figure 1D]This is a system diagram illustrating a further exemplary RAN and a further exemplary CN that may be used in the communication system illustrated in Figure 1A according to one embodiment. [Figure 2] This shows an example of channel information feedback from the receiver to the transmitter. [Figure 3] This section provides an example of a data-driven WTRU-specific codebook design. [Figure 4] This example shows a data-driven codebook during training for deep reinforcement learning (DRL) from the perspective of WTRU (Write-to-Run Time). [Figure 5] This example shows a data-driven codebook during training for DRL from the perspective of next-generation node B (gNB). [Figure 6] This document illustrates an exemplary signaling procedure during training between a data-driven codebook (gNB) and a WTRU when an AI / ML model (DRL) is employed in a WTRU. [Figure 7] This shows an example of message exchange from the perspective of WTRU during real-time data transmission and feedback. [Figure 8] This shows an example message exchange between a gNB and a WTRU during real-time data transmission. [Figure 9] This document describes an exemplary signaling procedure during training between the gNB and the WTRU of the data-driven codebook when an AI / ML model (DRL) is employed in the gNB. [Figure 10] This document illustrates an exemplary signaling procedure during training between a data-driven codebook (gNB) and a WTRU when an AI / ML model (DRL) is mirrored in both the gNB and WTRU. [Figure 11] This example shows a flow for determining a precoder using a precoder prediction model. [Modes for carrying out the invention]

[0009] Figure 1A illustrates an exemplary communication system 100 in which one or more disclosed embodiments may be implemented. The communication system 100 may be a multiple access system that provides content such as voice, data, video, message transmission, and broadcast to multiple wireless users. The communication system 100 may enable multiple wireless users to access such content through the sharing of system resources, including wireless bandwidth. For example, the communication system 100 may use 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 filtering OFDM, and filter bank multicarrier (FBMC).

[0010] As shown in Figure 1A, the communication system 100 may include radio transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, RAN 104 / 113, CN 106 / 115, public switched telephone network (PSTN) 108, the Internet 110, and other networks 112, but it will be understood that the disclosed embodiments intend any number of WTRUs, base stations, networks, and / or network elements. Each of the WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and / or communicate in a radio environment. For example, WTRU102a, 102b, 102c, 102d, any of which may be referred to as “station” and / or “STA (Station)”, may be configured to transmit and / or receive radio signals and may include user equipment (UE), mobile stations, fixed subscriber units or mobile subscriber units, subscriber-based units, radio paging, mobile phones, personal digital assistants (PDAs), smartphones, laptops, netbooks, personal computers, radio sensors, hotspots or Mi-Fi devices, Internet of Things (IoT) devices, watches or other wearable devices, head-mounted displays (HMDs), vehicles, drones, medical devices and applications (e.g., for remote surgery), industrial devices and applications (e.g., robots and / or other radio devices operating in an industrial and / or automated processing chain context), consumer electronics devices, devices operating on commercial radio networks and / or industrial radio networks, etc. WTRU102a, 102b, 102c, and 102d can all be referred to as UE for compatibility purposes.

[0011] The communication system 100 may also include base stations 114a and / or base stations 114b. Each of the base stations 114a and 114b may be any type of device configured to wirelessly interface with at least one of the WTRUs 102a, 102b, 102c, and 102d to facilitate access to one or more communication networks, such as CN 106 / 115, the Internet 110, and / or other networks 112. For example, base stations 114a and 114b may be a base transceiver station (BTS), node-B, encode-B, home node-B, home e-node-B, gNB, NR node-B, site controller, access point (AP), wireless router, etc. Although base stations 114a and 114b are each illustrated as single elements, it will be understood that base stations 114a and 114b may include any number of interconnected base stations and / or network elements.

[0012] Base station 114a may be part of RAN 104 / 113, which may also include other base stations and / or network elements (not shown), such as a base station controller (BSC), a radio network controller (RNC), and relay nodes. Base station 114a and / or base station 114b may be configured to transmit and / or receive radio signals on one or more carrier frequencies, which may be referred to as cells (not shown). These frequencies may be licensed spectra, unlicensed spectra, or combinations of licensed and unlicensed spectra. Cells may provide coverage of radio services to a particular geographic area that may be relatively fixed or change over time. Cells may be further divided into cell sectors. For example, a cell associated with base station 114a may be divided into three sectors. Thus, in one embodiment, base station 114a may include three transceivers, i.e., one transceiver per sector of the cell. In one embodiment, the base station 114a may employ multiple-input multiple output (MIMO) technology and utilize multiple transceivers per sector of the cell. For example, beamforming may be used to transmit and / or receive signals in a desired spatial direction.

[0013] Base stations 114a and 114b may communicate with one or more WTRUs 102a, 102b, 102c, and 102d via a radio interface 116, which may be any suitable radio communication link (e.g., radio frequency (RF), microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet (UV), visible light, etc.). The radio interface 116 may be established using any suitable radio access technology (RAT).

[0014] More specifically, as described above, the communication system 100 may be a multiple access system, but may use one or more channel access schemes such as CDMA, TDMA, FDMA, OFDMA, and SC-FDMA. For example, base stations 114a and WTRUs 102a, 102b, and 102c within RAN 104 / 113 may implement radio technologies such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may use wideband CDMA (WCDMA) to establish air interfaces 115 / 116 / 117. WCDMA may include communication protocols such as High-Speed ​​Packet Access (HSPA) and / or evolved HSPA (HSPA+). HSPA may include High-Speed ​​Downlink Packet Access (HSDPA) and / or High-Speed ​​UL Packet Access (HSUPA).

[0015] In one embodiment, base stations 114a and WTRUs 102a, 102b, and 102c may implement radio technologies such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which may establish a radio interface 116 using Long-Term Evolution (LTE) and / or LTE-Advanced (LTE-A) and / or LTE-Advanced Pro (LTE-A Pro).

[0016] In one embodiment, the base station 114a and WTRUs 102a, 102b, and 102c may implement radio technology such as NR radio access, which may establish a radio interface 116 using a new radio (NR).

[0017] 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. Accordingly, the radio interfaces utilized by the WTRUs 102a, 102b, 102c may be characterized by multiple types of radio access technologies and / or transmissions that are transmitted between multiple types of base stations (e.g., eNBs and gNBs).

[0018] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement wireless 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, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), IS-95, IS-856, Global System for Mobile communications (GSM), Enhanced Data rates for GSM Evolution (EDGE), GSM EDGE (GERAN), etc.

[0019] The base station 114b in FIG. 1A can be, for example, a wireless router, a home node B, a home e-node B, or an access point, but can utilize any suitable RAT to facilitate wireless connection in a local area such as a workplace, home, vehicle, campus, industrial facility, aerial corridor (for use by drones, for example), a location such as a road, etc. In one embodiment, the base station 114b and the WTRUs 102c, 102d can implement a wireless technology such as IEEE 802.11 to establish a wireless local area network (WLAN). In one embodiment, the base station 114b and the WTRUs 102c, 102d can implement a wireless technology such as IEEE 802.15 to establish a wireless personal area network (WPAN). In yet another embodiment, the base station 114b and the WTRUs 102c, 102d can utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.) to establish a pico cell or a femto cell. As shown in FIG. 1A, the base station 114b can have a direct connection to the Internet 110. Thus, the base station 114b may not need to access the Internet 110 via the CN 106 / 115.

[0020] RAN104 / 113 can communicate with CN106 / 115, which may be any type of network configured to provide voice, data, applications, and / or Voice over Internet Protocol (VoIP) services to one or more of WTRU102a, 102b, 102c, and 102d. The data may have various quality of service (QoS) requirements, such as different throughput requirements, latency requirements, error tolerance requirements, reliability requirements, data throughput requirements, and mobility requirements. CN106 / 115 may provide call control, billing services, mobile location-based services, prepaid calls, internet connectivity, video distribution, etc., and / or implement high-level security functions such as user authentication. Although not shown in Figure 1A, it will be understood that RAN104 / 113 and / or CN106 / 115 may communicate directly or indirectly with other RANs employing the same RAT as RAN104 / 113 or different RATs. For example, in addition to being connected to RAN104 / 113 which may utilize NR radio technology, CN106 / 115 may also communicate with another RAN (not shown) using GSM, UMTS, CDMA2000, WiMAX, E-UTRA, or WiFi radio technology.

[0021] CN106 / 115 may also function as a gateway for WTRU102a, 102b, 102c, 102d to access PSTN108, the Internet 110, and / or other networks 112. PSTN108 may include a circuit-switched telephone network providing plain old telephone service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices, where these networks and devices use common communication protocols such as the transmission control protocol (TCP), the user datagram protocol (UDP), and / or the Internet protocol (IP) of the TCP / IP Internet Protocol suite. Network 112 may include wired and / or wireless communication networks owned and / or operated by other service providers. For example, network 112 may include another CN connected to one or more RANs, which may employ the same RAT as RAN104 / 113, or a different RAT.

[0022] Some or all of the WTRUs 102a, 102b, 102c, and 102d in the communication system 100 may include multimode functionality (for example, WTRUs 102a, 102b, 102c, and 102d may include multiple transceivers for communicating with different radio networks via different radio links). For example, WTRU 102c shown in Figure 1A may be configured to communicate with base station 114a, which may employ cellular-based radio technology, and base station 114b, which may employ IEEE 802 radio technology.

[0023] Figure 1B is a system diagram illustrating an example WTRU102. As shown in Figure 1B, the WTRU102 may include, among other things, a processor 118, a transceiver 120, a transmit / receive element 122, a speaker / microphone 124, a keypad 126, a display / touchpad 128, non-removable memory 130, removable memory 132, a power supply 134, a global positioning system (GPS) chipset 136, and / or other peripherals 138. It will be understood that the WTRU102 may include any partial combination of the aforementioned elements while maintaining consistency with one embodiment.

[0024] The processor 118 may be a general-purpose processor, a dedicated processor, a conventional processor, a digital signal processor (DSP), multiple microprocessors, one or more microprocessors associated with a DSP core, a controller, a microcontroller, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) circuit, any other type of integrated circuit (IC), a state machine, etc. The processor 118 may perform signal coding, data processing, power control, input / output processing, and / or any other functions that enable the WTRU 102 to operate in a wireless environment. The processor 118 may be coupled to a transceiver 120 which may be coupled to a transmit / receive element 122. Figure 1B illustrates the processor 118 and transceiver 120 as separate components, but it will be understood that the processor 118 and transceiver 120 may be integrated together in an electronic package or chip.

[0025] The transmit / receive element 122 may be configured to transmit or receive signals to and from a base station (e.g., base station 114a) via the radio interface 116. For example, in one embodiment, the transmit / receive element 122 may be an antenna configured to transmit and / or receive RF signals. In one embodiment, the transmit / receive element 122 may be an emitter / detector configured to transmit and / or receive, for example, IR signals, UV signals, or visible light signals. In yet another embodiment, the transmit / receive element 122 may be configured to transmit and / or receive both RF signals and optical signals. It will be understood that the transmit / receive element 122 may be configured to transmit and / or receive any combination of radio signals.

[0026] Although the transmit / receive element 122 is illustrated as a single element in Figure 1B, the WTRU 102 may include any number of transmit / receive elements 122. More specifically, the WTRU 102 may employ MIMO technology. Thus, in one embodiment, the WTRU 102 may include two or more transmit / receive elements 122 (e.g., multiple antennas) for sending and receiving radio signals via the air interface 116.

[0027] The transceiver 120 may be configured to modulate the signal transmitted by the transmit / receive element 122 and demodulate the signal received by the transmit / receive element 122. As described above, the WTRU 102 may have multimode capabilities. Therefore, the transceiver 120 may include multiple transceivers to enable the WTRU 102 to communicate via multiple RATs, such as NR and IEEE 802.11.

[0028] The processor 118 of the WTRU102 may be coupled to a speaker / microphone 124, a keypad 126, and / or a display / touchpad 128 (e.g., a liquid crystal display (LCD) display unit or an organic light-emitting diode (OLED) display unit) and may receive user input from these. 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 any suitable type of memory, such as non-removable memory 130 and / or removable memory 132, and store data in such memory. The non-removable memory 130 may include random-access memory (RAM), read-only memory (ROM), a hard disk, or any other type of memory storage device. The removable memory 132 may include a subscriber identity module (SIM) card, a memory stick, a secure digital (SD) memory card, and the like. In other embodiments, the processor 118 may access information from memory not physically located on the WTRU 102, such as on a server or home computer (not shown), and store data in that memory.

[0029] The processor 118 may receive power from the power supply 134 and be configured to distribute and / or control power to other components within the WTRU 102. The power supply 134 may be any suitable device for supplying power to the WTRU 102. For example, the power supply 134 may include one or more dry cell batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion), etc.), a solar cell, a fuel cell, etc.

[0030] The processor 118 may also be coupled to a GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) regarding the current location of the WTRU 102. In addition to, or instead of, the WTRU 102 may receive location information from base stations (e.g., base stations 114a, 114b) via the radio interface 116 and / or determine its location based on the timing of signals received from two or more nearby base stations. It will be understood that the WTRU 102 may acquire location information by any preferred location determination method while maintaining consistency with one embodiment.

[0031] The processor 118 may be further coupled to other peripherals 138, which may include one or more software and / or hardware modules that provide additional features, functions, and / or wired or wireless connectivity. For example, peripherals 138 may include an accelerometer, an electronic compass, a satellite transceiver, a digital camera (for photos and / or videos), a universal serial bus (USB) port, a vibration device, a television transceiver, a hands-free headset, a Bluetooth® module, a frequency modulated (FM) radio unit, a digital music player, a media player, a video game player module, an internet browser, a virtual reality and / or augmented reality (VR / AR) device, an activity tracker, and the like. The peripheral device 138 may include one or more sensors, which may be one or more of the following: gyroscope, accelerometer, Hall effect sensor, magnetometer, compass sensor, proximity sensor, temperature sensor, time sensor, geolocation sensor, altimeter, light sensor, touch sensor, magnetometer, barometer, gesture sensor, biometric sensor, and / or humidity sensor.

[0032] WTRU102 may include a full-duplex radio in which the transmission and reception of some or all of the signals (e.g., associated with specific subframes for both UL (e.g., transmission) and downlink (e.g., reception) may be in parallel and / or simultaneous. The full-duplex radio may include an interference management unit for reducing and / or substantially eliminating self-interference through signal processing either through hardware (e.g., chokes) or through a processor (e.g., via a separate processor (not shown) or processor 118). In one embodiment, WRTU102 may include a half-duplex radio for the transmission and reception of any of the signals (e.g., associated with specific subframes for either UL (e.g., transmission) or downlink (e.g., reception)).

[0033] Figure 1C is a system diagram illustrating RAN104 and CN106 according to one embodiment. As described above, RAN104 can communicate with WTRU102a, 102b, and 102c via the air interface 116 using E-UTRA wireless technology. RAN104 can also communicate with CN106.

[0034] RAN104 may include e-nodes-B160a, 160b, and 160c, but it will be understood that RAN104 may include any number of e-nodes-B while maintaining consistency with one embodiment. Each of e-nodes-B160a, 160b, and 160c may include one or more transceivers for communicating with WTRU102a, 102b, and 102c via the radio interface 116. In one embodiment, e-nodes-B160a, 160b, and 160c may implement MIMO technology. Thus, e-node-B160a may, for example, use multiple antennas to transmit radio signals to and / or receive radio signals from WTRU102a.

[0035] Each of the e-nodes-B160a, 160b, and 160c may be associated with a specific cell (not shown) and may be configured to handle wireless resource management decisions, handover decisions, user scheduling, etc., in UL and / or DL. As shown in Figure 1C, the e-nodes-B160a, 160b, and 160c may communicate with each other via the X2 interface.

[0036] The CN106 shown in Figure 1C may include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (or PGW) 166. Although each of the aforementioned elements is illustrated as part of CN106, it will be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0037] The MME162 can be connected to each of the e-nodes—B162a, 162b, and 162c—in RAN104 via the S1 interface and can function as a control node. For example, the MME162 may perform roles such as authenticating users of WTRU102a, 102b, and 102c, activating / deactivating bearers, and selecting a specific serving gateway during the initial attachment of WTRU102a, 102b, and 102c. The MME162 may provide control plane functionality for switching between RAN104 and other RANs (not shown) employing other radio technologies such as GSM and / or WCDMA.

[0038] The SGW164 can be connected to each of the e-nodes B160a, 160b, and 160c in RAN104 via the S1 interface. The SGW164 can generally route and forward user data packets to and from WTRU102a, 102b, and 102c. The SGW164 can perform other functions, such as anchoring the user plane during e-node B handovers, triggering paging when DL data is available to WTRU102a, 102b, and 102c, and managing and remembering the context of WTRU102a, 102b, and 102c.

[0039] SGW164 may be connected to PGW166, which may provide WTRU102a, 102b, and 102c with access to a packet-switched network such as the Internet 110 to facilitate communication between WTRU102a, 102b, and 102c and IP-enabled devices.

[0040] CN106 can facilitate communication with other networks. For example, CN106 can provide WTRU102a, 102b, and 102c with access to a circuit-switched network such as PSTN108 to facilitate communication between WTRU102a, 102b, and 102c and conventional terrestrial line communication devices. For example, CN106 may include, or communicate with, an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that functions as an interface between CN106 and PSTN108. In addition, CN106 may provide WTRU102a, 102b, and 102c with access to another network 112, which may include other wired and / or wireless networks owned and / or operated by other service providers.

[0041] Although the WTRU is shown as a wireless terminal in Figures 1A to 1D, in certain representative embodiments, such a terminal is intended to be able to use a wired communication interface with a communication network (for example, temporarily or permanently).

[0042] In a typical embodiment, the other network 112 may be a WLAN.

[0043] A WLAN in Infrastructure Basic Service Set (BSS) mode may have access points (APs) of the BSS and one or more stations (STAs) associated with the APs. APs may have access to or interfaces with other types of wired / wireless networks that carry traffic entering and / or leaving the Distribution System (DS) or BSS. Traffic originating outside the BSS and destined for the STAs may reach and be delivered to the STAs via the APs. Traffic originating from the STAs for destinations outside the BSS may be sent to the APs and then delivered to their respective destinations. Traffic between STAs within the BSS may be transmitted, for example, through the APs, with the source STA sending traffic to the AP, and the AP delivering the traffic to the destination STA. Traffic between STAs within the BSS may be considered and / or referred to as peer-to-peer traffic. Peer-to-peer traffic may be transmitted between the source STA and the destination STA (for example, directly between them) using a direct link setup (DLS). In certain representative embodiments, the DLS may use 802.11e DLS or 802.11z tunneled DLS (TDLS). A WLAN using Independent BSS (IBSS) mode may not have APs, and STAs within or using IBSS (e.g., all STAs) may communicate directly with one another. The IBSS mode of communication may be referred to herein as “ad hoc” communication mode.

[0044] When using the 802.11ac infrastructure operating mode or a similar operating mode, an AP may transmit beacons on a fixed channel, such as the primary channel. The primary channel may be of a fixed width (e.g., a 20 MHz bandwidth) or a width dynamically set via signaling. The primary channel may be the operating channel of the BSS, but may be used by an STA to establish a connection with the AP. In certain typical embodiments, for example, in an 802.11 system, Carrier Sense Multiple Access with Collision Avoidance (CSMA / CA) may be implemented. In the case of CSMA / CA, an STA, including the AP (e.g., all STAs), may sense the primary channel. If the primary channel is sensed / detected and / or determined to be busy by a particular STA, that STA may be backed off. A single STA (e.g., only one station) may transmit at any given time in a given BSS.

[0045] High-throughput (HT) STAs may use a 40 MHz wide channel for communication, which may be formed, for example, through a combination of a primary 20 MHz channel and adjacent or non-adjacent 20 MHz channels.

[0046] Very High Throughput (VHT) STAs can support channels with widths of 20 MHz, 40 MHz, 80 MHz, and / or 160 MHz. 40 MHz and / or 80 MHz channels can be formed by combining multiple consecutive 20 MHz channels. 160 MHz channels can be formed by combining eight consecutive 20 MHz channels, or by combining two non-contiguous 80 MHz channels, which may be referred to as an 80+80 configuration. In the 80+80 configuration, after channel coding, the data can pass through a segment parser that can split the data into two streams. Inverse Fast Fourier Transform (IFFT) processing and time-domain processing can be performed separately for each stream. The streams may be mapped to two 80 MHz channels, and the data can be transmitted by a transmitting STA. In the receiver of a receiving STA, the operation described above for the 80+80 configuration may be reversed, and the combined data may be transmitted to Medium Access Control (MAC).

[0047] Sub-1 GHz operating modes are supported by 802.11af and 802.11ah. Channel operating bandwidth and carrier are reduced in 802.11af and 802.11ah compared to those used in 802.11n and 802.11ac. 802.11af supports bandwidths of 5 MHz, 10 MHz, and 20 MHz in the TV White Space (TVWS) spectrum, while 802.11ah supports bandwidths of 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz using the non-TVWS spectrum. According to a typical embodiment, 802.11ah may support meter-type control / machine-type communications, such as MTC devices within a macro-notification range area. MTC devices may have limited capabilities, including support for specific bandwidths and / or limited bandwidths (e.g., support for these only). MTC devices may include batteries with battery life exceeding a threshold (e.g., to maintain very long battery life).

[0048] A WLAN system capable of supporting multiple channels and channel bandwidths such as 802.11n, 802.11ac, 802.11af, and 802.11ah includes a channel that can be designated as the primary channel. The primary channel may have a bandwidth equal to the maximum common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel may be set and / or limited by an STA from among all STAs operating in a BSS that support the minimum bandwidth operating mode. In the 802.11ah example, the primary channel may be 1 MHz wide for an STA (e.g., an MTC type device) that supports (e.g., only) the 1 MHz mode, even if the AP and other STAs in the BSS support 2 MHz, 4 MHz, 8 MHz, 16 MHz, and / or other channel bandwidth operating modes. Carrier sensing and / or Network Allocation Vector (NAV) settings may depend on the status of the primary channel. For example, if the primary channel is busy due to an STA (which only supports 1MHz operating mode) transmitting to the AP, a large portion of the frequency band may remain idle and could be considered busy, even if it were available.

[0049] In the United States, the available frequency band that can be used by 802.11ah is 902MHz to 928MHz. In South Korea, the available frequency band is 917.5MHz to 923.5MHz. In Japan, the available frequency band is 916.5MHz to 927.5MHz. The total bandwidth available for 802.11ah is 6MHz to 26MHz, depending on the country code.

[0050] Figure 1D is a system diagram illustrating RAN113 and CN115 according to one embodiment. As described above, RAN113 employs NR radio technology and can communicate with WTRU102a, 102b, and 102c via the radio interface 116. RAN113 can also communicate with CN115.

[0051] RAN113 may include gNB180a, 180b, and 180c, but it will be understood that RAN113 may include any number of gNBs while maintaining consistency with one embodiment. Each of gNB180a, 180b, and 180c may include one or more transceivers for communicating with WTRU102a, 102b, and 102c via the radio interface 116. In one embodiment, gNB180a, 180b, and 180c may implement MIMO technology. For example, gNB180a and 108b may use beamforming to transmit signals to and / or receive signals from gNB180a, 180b, and 180c. Thus, gNB180a may, for example, use multiple antennas to transmit and / or receive radio signals to and from WTRU102a. In one embodiment, gNB180a, 180b, and 180c may implement carrier aggregation technology. For example, gNB180a may transmit multiple elemental carriers to WTRU102a (not shown). A subset of these elemental carriers may be on the unlicensed spectrum, while the remaining elemental carriers may be on the licensed spectrum. In one embodiment, gNB180a, 180b, and 180c may implement coordinated multi-point (CoMP) technology. For example, WTRU102a may receive coordinated transmissions from gNB180a and gNB180b (and / or gNB180c).

[0052] WTRU102a, 102b, and 102c may communicate with gNB180a, 180b, and 180c using transmissions associated with scalable neurology. For example, OFDM symbol intervals and / or OFDM subcarrier intervals may vary for different transmissions, different cells, and / or different portions of the radio transmission spectrum. WTRU102a, 102b, and 102c may also communicate with gNB180a, 180b, and 180c using subframes or transmission time intervals (TTIs) of varying or scalable lengths (e.g., containing varying numbers of OFDM symbols and / or having varying absolute time durations).

[0053] gNB180a, 180b, and 180c can be configured to communicate with WTRU102a, 102b, and 102c in standalone and / or non-standalone configurations. In a standalone configuration, WTRU102a, 102b, and 102c can communicate with gNB180a, 180b, and 180c without accessing other RANs (e.g., e-node-B160a, 160b, and 160c). In a standalone configuration, WTRU102a, 102b, and 102c can utilize one or more of gNB180a, 180b, and 180c as mobility anchor points. In a standalone configuration, WTRU102a, 102b, and 102c can communicate with gNB180a, 180b, and 180c using signals in unauthorized bands. In a non-standalone configuration, WTRU102a, 102b, and 102c can communicate with and connect to gNB180a, 180b, and 180c, while also communicating with and connecting to other RANs such as e-nodes-B160a, 160b, and 160c. For example, WTRU102a, 102b, and 102c can implement DC principles for substantially simultaneous communication with one or more gNB180a, 180b, and 180c and one or more e-nodes-B160a, 160b, and 160c. In a non-standalone configuration, e-nodes B160a, 160b, and 160c can function as mobility anchors for WTRU102a, 102b, and 102c, and gNB180a, 180b, and 180c can provide additional coverage and / or throughput to service WTRU102a, 102b, and 102c.

[0054] Each of the gNB180a, 180b, and 180c may be associated with a specific cell (not shown) and may be configured to handle wireless resource management decisions, handover decisions, user scheduling in UL and / or DL, support for network slicing, dual connectivity, interworking between NR and E-UTRA, routing of user plane data to User Plane Functions (UPFs) 184a and 184b, routing of control plane information to Access and Mobility Management Functions (AMFs) 182a and 182b, and so on. As shown in Figure 1D, the gNB180a, 180b, and 180c can communicate with each other via the Xn interface.

[0055] The CN115 shown in Figure 1D may include at least one AMF182a, 182b, at least one UPF184a, 184b, at least one Session Management Function (SMF)183a, 183b, and optionally a Data Network (DN)185a, 185b. Although each of the aforementioned elements is illustrated as part of the CN115, it should be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0056] AMF182a and 182b can be connected to one or more gNB180a, 180b, and 180c in RAN113 via the N2 interface and can function as control nodes. For example, AMF182a and 182b may perform roles such as user authentication for WTRU102a, 102b, and 102c, support for network slicing (e.g., handling different PDU sessions with different requirements), selection of specific SMF183a and 183b, management of registration areas, termination of NAS signaling, and mobility management. Network slicing can be used by AMF182a and 182b to customize CN support for WTRU102a, 102b, and 102c based on the type of service utilizing WTRU102a, 102b, and 102c. For example, different network slices may be established for different use cases, such as services relying on ultra-reliable low latency (URLLC) access, services relying on enhanced mobile broadband (eMBB) access, and services for machine-type communication (MTC) access. AMF162 may provide control plane functions for exchange between RAN113 and other RANs (not shown) using other radio technologies such as LTE, LTE-A, LTE-A Pro, and / or WiFi.

[0057] SMF183a and 183b may be connected to AMF182a and 182b in CN115 via the N11 interface. SMF183a and 183b may also be connected to UPF184a and 184b in CN115 via the N4 interface. SMF183a and 183b may select and control UPF184a and 184b and configure the routing of traffic through UPF184a and 184b. SMF183a and 183b may perform other functions such as managing and assigning UE IP addresses, managing PDU sessions, controlling policy enforcement and QoS, and providing downlink data notifications. PDU session types may be IP-based, non-IP-based, Ethernet-based, etc.

[0058] UPF184a and 184b can connect to one or more gNB180a, 180b, and 180c within RAN113 via the N3 interface, thereby providing WTRU102a, 102b, and 102c with access to a packet-switched network such as the Internet 110 to facilitate communication between WTRU102a, 102b, and 102c and IP-enabled devices. UPF184 and 184b can perform other functions such as routing and forwarding packets, enforcing user plane policies, supporting multi-homed PDU sessions, handling user plane QoS, buffering downlink packets, and providing mobility anchoring.

[0059] CN115 can facilitate communication with other networks. For example, CN115 may include, or communicate with, an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that functions as an interface between CN115 and PSTN108. In addition, CN115 may provide WTRU102a, 102b, 102c with access to another network 112, which may include other wired and / or wireless networks owned and / or operated by other service providers. In one embodiment, WTRU102a, 102b, 102c may be connected to the local data network (DN) 185a, 185b via UPF184a, 184b through an N3 interface to UPF184a, 184b, and an N6 interface between UPF184a, 184b and DN185a, 185b.

[0060] As can be seen from Figures 1A to 1D and their corresponding descriptions, one or more of the functions described herein relating to one or more of the WTRU102a to d, base stations 114a to b, e-node-B160a to c, MME162, SGW164, PGW166, gNB180a to c, AMF182a to b, UPF184a to b, SMF183a to b, DN185a to b, and / or any other devices described herein may be implemented by one or more emulation devices (not shown). An emulation device may be one or more devices configured to emulate one or more of the functions described herein. For example, an emulation device may be used to test other devices and / or simulate network and / or WTRU functions.

[0061] Emulation devices may be designed to implement testing of one or more other devices in a laboratory and / or carrier network environment. For example, one or more emulation devices may perform one or more or all of the functions while fully or partially implemented and / or deployed as part of a wired and / or wireless network to test other devices in a communications network. One or more emulation devices may perform one or more or all of the functions while temporarily implemented / deployed as part of a wired and / or wireless network. Emulation devices may be directly coupled to another device for testing purposes and / or may perform testing using terrestrial wireless communication.

[0062] One or more emulation devices may perform one or more functions, including all of the above, while not implemented / deployed as part of a wired and / or wireless communication network. For example, an emulation device may be used in a test laboratory test scenario, and / or in a wired and / or wireless communication network that is not deployed (e.g., for testing purposes), to implement testing of one or more components. One or more emulation devices may be test equipment. Direct RF coupling and / or wireless communication via RF circuitry (e.g., which may include one or more antennas) may be used by the emulation device to transmit and / or receive data.

[0063] Systems, methods, and means for MIMO precoder codebooks specific to data-driven wireless transmit-receive units (WTRUs) are disclosed herein. Quality of service (e.g., BER) may be improved, for example, by using a precoder for data transmission, which is selected from a codebook constructed from observed data. A wireless transmit / receive unit (WTRU) may construct a codebook (e.g., with a base station) based on observed data (e.g., time-varying channel conditions) including a precoder to be used for data transmission. The WTRU may determine the codebook, for example, by using a precoder prediction model (e.g., by using machine learning and / or artificial intelligence).

[0064] The WTRU may construct a codebook (e.g., with a base station) based on observed data using a precoder prediction model. The WTRU may include a processor. The WTRU may determine precoder spatial selection information. The precoder spatial selection information may include WTRU-specific precoder action spatial information. The WTRU may determine precoder spatial selection information from a base station (e.g., the WTRU may establish precoder spatial selection information by transmitting a reference signal to the base station). The WTRU may receive first channel state information from the base station (e.g., in a channel state information reference signal (CSI-RS)). The WTRU may select a first precoder from WTRU-specific precoder action spatial information. The WTRU may determine a first reward value for the first precoder (e.g., using a precoder prediction model). The first reward value may be associated with a first CSI-RS. The WTRU may determine, for example, based on the first reward value, whether the precoder prediction model has converged (e.g., a condition is met). If the precoder prediction model converges, the WTRU may indicate to the base station that the model has converged, as well as the precoder and reward values ​​associated with the convergence.

[0065] The WTRU may determine, based on the first reward value, that the precoder prediction model has not converged. The WTRU may select a second precoder from the precoder spatial selection information. The WTRU may determine a second reward value for the second precoder. The WTRU may continue to select precoders and determine their associated reward values ​​to determine model convergence, for example, until the model converges or until several iterations have passed.

[0066] The WTRU may receive a second CSI-RS from the base station (for example, after the model has converged). The WTRU may use the second CSI-RS and the precoder prediction model to determine the predicted precoder. The WTRU may generate a codebook using the precoder used to determine model convergence and the predicted precoder.

[0067] The WTRU may include a processor configured to perform several actions. A sound reference signal (SRS) may be transmitted to the network. Precoder spatial selection information may be received from the network. A data transmission and channel status information reference signal (CSI-RS) may be received from the network. A reward value may be calculated and provided to the precoder predictor model along with the CSI-RS as input for acquiring precoders. The acquired precoders may be transmitted to the network. The precoder predictor model may be determined to be converged. A set of precoders may be requested from the network. A set of precoders may be received from the network, and an acceptance notification signal may be transmitted to the network.

[0068] References to gNBs in this specification may refer to exemplary base stations, and gNBs may be replaced with any other suitable base stations.

[0069] Employing channel adaptive signaling in wireless communication systems can result in improvements (e.g., significant improvements) in performance metrics. These adaptive techniques may utilize channel knowledge at the transmitter. Channel knowledge may not be directly utilized in frequency division duplex systems. Adaptation (e.g., near-optimal adaptation) may be enabled by the receiver transmitting feedback (e.g., bits related to channel conditions such as channel quality and rank). Feedback of channel information by the receiver to the transmitter (e.g., as described herein) may be referred to as a limited or finite-rate feedback system. With feedback (e.g., carefully designed feedback), a suboptimal transmitter channel knowledge system can achieve near-optimal performance.

[0070] A receiver employing feedback may use a low-rate data stream (e.g., on the reverse side of the link) to transmit channel information to the transmitter (e.g., on the forward side of the link). For example, downlink carrier frequency channel information may be transmitted by the receiver on the uplink carrier frequency. Downlink carrier frequency information may include channel state information (CSI), channel quality indicator (CQI), channel rank indicator (RI), precoder matrix indicator (PMI), interference level, etc. The type of feedback transmitted by the receiver may be network-dependent (e.g., network requirements). This information may convey some concept of forward link conditions (e.g., channel state, received power, interference level, etc.). The transmitter may use the information to adapt forward link transmission. The value of the feedback may vary with the system scenario.

[0071] Figure 2 shows an example of channel information feedback from a receiver (e.g., a WTRU) to a transmitter (e.g., a base station such as a gNB). The WTRU may feed back the index of the precoder matrix from a codebook of size 2B, where B may be the number of bits used to transmit the index.

[0072] The receiver, WTRU, may acquire downlink channel knowledge, for example, using a reference symbol transmitted by the gNB. The WTRU may estimate the channel and select a precoder from a given codebook that may be available to the gNB and WTRU. The codebook may include a set of precoders that may be tuned / designed (for example, according to a specific assumed channel distribution). The type of precoder may correspond to channel eigenvalues, phase quantization values, and / or quantized channel matrices. This type of selection of precoders from a given codebook is shown in Figure 2. In this way, the receiver can control how the signal may be adapted to the channel.

[0073] The number of feedback bits (e.g., the number of feedback bits used to transmit channel information) may depend on the codebook size. For a codebook of size 2^B, B bits of the selected precoder may be transmitted via the feedback channel. The rate and / or signal-to-noise ratio (SNR) may be known as side information to facilitate communication and may be fed back.

[0074] Channel state information (e.g., obtained through feedback) may be outdated or subject to feedback errors (e.g., hardware failures). Due to these errors, the transmitter may adapt the transmit power and / or data rate according to such incomplete channel state and idle time (CSIT) information. Error statistics of the CSIT information may be considered in the adaptation, for example, to effectively utilize the incomplete channel information in the transmitter. For example, since error statistics may depend on the channel environment and / or Doppler spectrum, it may be difficult (e.g., very difficult) for the transmitter to obtain and / or track error statistics. In such cases, ACK / NAK signaling from higher-layer ARQs may be useful (e.g., very useful) to provide closed-loop adaptation (e.g., true closed-loop adaptation).

[0075] Using feedback can generate overhead on one side of the link while benefiting from the achievable data rate on the other side. Feedback can sometimes be significant. For example, the overhead associated with feedback (e.g., for multi-user scenarios) could be several hundred bits. This can (e.g., significantly) reduce the system's throughput.

[0076] Precoding / codebook design for MIMO systems may face time-varying channel conditions.

[0077] The selection of PMI using channel estimates in a WTRU may be inaccurate for one or more of the following reasons: Hardware imperfections resulting from nonlinear components may distort channel estimates. Delays in the feedback from the WTRU to the base station (e.g., gNB) due to channel aging may age the PMI in the gNB. Codebooks determined based on fixed probability distributions to represent radio channels (e.g., urban, rural) may result in high quantization errors. The large overhead in codebooks for multiple user, multiple input, multiple output (MU-MIMO) (e.g., Type II CSI codebooks) may make higher rank (e.g., rank greater than 3) transmissions impractical. For example, the feedback for rank-2 may be around 500 bits.

[0078] Methods for designing codebooks specific to data-driven WTRUs may improve quality of service (e.g., bit error ratio (BER)). Precoders for data transmission at base stations (e.g., gNBs) may be selected from codebooks constructed from observed data, for example. Base stations and WTRUs can identify (e.g., allow, enable) codewords (e.g., precoders) that are (e.g., near-optimal) adapted to time-varying channel conditions.

[0079] A codebook design specific to data-driven WTRUs may be implemented.

[0080] A data-driven WTRU-specific codebook design for a single-user MIMO system may be implemented, for example, by using channel estimates in the WTRU. In such a design, the feature mapping between channel estimates and precoder selection may be designed using data-driven methods such as machine learning or deep reinforcement learning. This method (e.g., method) may determine a precoder that adapts to the CSI observed at the base station (e.g., gNB) during data transmission, for example in real time (e.g., this method may be used by the WTRU to make the determination). The WTRU may receive precoder matrix indices as feedback from the WTRU-specific codebook. The WTRU-specific codebook may be designed, for example, based on channel estimates observed over a period of time. The WTRU-specific codebook may be obtained by training over real-time data. A precoder related to the time-varying channel observed in the WTRU may be designed (e.g., designed first). The precoder may be quantized (e.g., subsequently) to derive the WTRU-specific codebook. The codebook may be WTRU-specific, for example, because the codebook is designed based on the channel estimates observed in that particular WTRU. The gNB may, for example, use the PMI fed back by the WTRU to select a precoder for data transmission from the same codebook. The gNB and / or the WTRU may update the WTRU-specific codebook using observations (e.g., data based on new observations), for example, depending on the BER. This method may provide better performance with respect to the BER. Such better performance may be due to the codebook being designed from observed data samples rather than from simplified assumptions of a manageable probability distribution.

[0081] Figure 3 shows an exemplary data-driven WTRU-specific codebook design, in which one or more of the indicated actions may be performed. In 301, the gNB can construct the WTRU with parameters (e.g., training iteration / convergence time) and may send CSI-RS for channel estimation (H) in the WTRU.

[0082] In 302, the WTRU may select a downlink (DL) precoder (e.g., for gNB) for the next transmission opportunity (TxOP). The WTRU may select a DL precoder from a WTRU-specific data-driven codebook, for example, using the estimated channel H. A data-driven codebook design (e.g., a training aspect) is described herein. The codebook may be constructed from a set of precoder matrices, which may be designed by a data-driven method (e.g., machine learning (ML) based on channel state observations in the WTRU).

[0083] In an exemplary scenario (e.g., Scenario 1), the training phase may begin, for example, before codebook construction (e.g., in the initial phase). The WTRU may observe a channel estimate H (e.g., which may represent a state). The WTRU may select a precoder P (e.g., which may represent an action from a continuous action space, e.g., select a precoder from a set of possible precoders) (e.g., based on observing the channel estimate H). The WTRU may feed the precoder back to the gNB. The WTRU may use the precoder in the next transmission opportunity (TxOP). The desired metric (e.g., rate / BER) may be optimized.

[0084] In the example, training may be employed (e.g., offline) using data that may be obtained by simulation (e.g., based on knowledge of channel statistics). Model parameters (e.g., for a deep reinforcement learning (DRL) model) for obtaining a precoder may be trained using this data, for example.

[0085] In the example, the initial parameters of the model may be adopted, for example, using offline training based on simulated data. The initial parameters may be updated, for example, using online training based on real-time data. This method may ensure faster convergence and / or better performance of the model.

[0086] In the example, the precoder prediction model may be constructed using DRL. The training samples (in a precoder prediction model constructed using DRL, for example) may include channel estimates H (which may represent states), precoders P (which may represent actions), and / or rewards (e.g., rate / BER).

[0087] WTRU allows us to conclude that a model (e.g., a DRL model) is trained if, for example, model parameters (e.g., DRL parameters) such as reward (e.g., BER) converge.

[0088] A continuous action space may be used to select an initial random precoder. The continuous action space may be divided into a set of smaller continuous action spaces, for example, to reduce the convergence time and / or iterations of the training model (e.g., a DRL model). These action spaces may be shared with the gNB and WTRU, for example, offline (e.g., pre-configured and / or stored on the gNB and WTRU). The gNB may, for example, send instructions to the WTRU (e.g., in the DCI) indicating the index of the precoder action space (e.g., configuring the WTRU with the DCI) during model training. The WTRU may, for example, select a precoder (e.g., a random precoder) from the precoder action space first (e.g., for data transmission, depending on the CSI estimate in the WTRU) during model training. This initial selection of a random precoder for training the model (DRL) may be WTRU-specific, because, for example, the CSI for each WTRU may be different and / or may be different precoder action spaces. In the example, the gNB may send instructions to the WTRU (e.g., in the DCI) indicating an index of the precoder action space (e.g., constructing the WTRU using the DCI) based on one or more of the following: The gNB may obtain the CSI based on the SRS received from the WTRU on the uplink. The gNB may identify the precoder action space for that particular WTRU based on the CSI.

[0089] In the example, the initial precoder may be selected from a predefined codebook (which could be an existing network-based (e.g., NR-based) codebook) to reduce convergence time, for example.

[0090] WTRU may, for example, use the trained precoder model (DRL) parameters to obtain a set of precoders Sp={P1,P2,...,PN} across a variety of channel realizations {H1,H1,...,HN} (for example, in the next phase) (if a precoder predictor model (e.g., a DRL model) is trained). The set of precoders may be fed back to gNB after channel realization (e.g., after each channel realization). In the example, a (e.g., existing) CSI-RS signal may be used to feed the precoders and / or used in the training phase (e.g., which may implicitly reduce overhead).

[0091] WTRU may employ a quantization scheme to obtain the codebook (for example, in the final phase) if a set of precoders is obtained.

[0092] In an exemplary scenario (e.g., Scenario 2), during training, the gNB may indicate in the DCI (e.g., constructed using the DCI) the number of bits (e.g., B bits) to be used in the precoder feedback by the WTRU in the UL. The WTRU may feed back the precoder quantized to B bits to the gNB. The gNB may transmit data and / or CSI-RS using the quantized precoder transmitted by the WTRU, for example. The WTRU may calculate a reward using the quantized precoder based on the signal received from the gNB, for example.

[0093] In an exemplary scenario (e.g., Scenario 3), training using a DRL (e.g., an AI / ML engine) may be employed in the gNB. Precoder selection during DRL training may be employed by the gNB. The gNB may, for example, transmit data and / or CSI-RS using the selected precoder. The WTRU may, for example, calculate a reward (e.g., BER) in response to receiving the data and CSI-RS. The WTRU may, for example, feed back the reward and / or compressed CSI to the gNB using uplink control information (UCI) or a push transmission. This process may continue, for example, until the reward (e.g., BER) converges, or over a number of iterations (e.g., a pre-configured number). If DRL is employed by the gNB and the precoder is selected by the gNB during DRL training, the following scenarios may occur: In Case 1, for example, the gNB transmits a precoded DMRS, so the WTRU may be transparent to the precoder selected by the gNB. In this case, the WTRU may use DMRS to calculate the reward (e.g., BER) and feed back the reward and compressed effective CSI to the gNB. The effective CSI could be, for example, Heff = HP, where H is the channel, P is the precoder, and Heff is the product of H and P. In case 2, for example, the gNB sends CSI-RS to estimate the precoder selected by the gNB in ​​addition to DMRS, so the WTRU may be aware of the precoder selected by the gNB. In this case, the WTRU may feed back the reward and compressed CSI to the gNB.

[0094] In an exemplary scenario (e.g., Scenario 4), the DRL training employed by the gNB may be mirrored in the WTRU. In this case, both the gNB and the WTRU employ the DRL. The initial random seed and / or model parameters for the DRL for precoder selection may be indicated (e.g., configured) by the gNB. For example, configuration information (e.g., indicating the initial random seed and / or model parameters) may be sent to the WTRU using DCI. The gNB may send data and CSI-RS to the WTRU. The WTRU can calculate the reward and may feed back the reward and compressed CSI to the gNB. In this case, the WTRU can identify (e.g., accurately identify) the precoder selected in the gNB without precoder estimates, for example, because the DRL parameters and initial random seed are shared between the gNB and the WTRU.

[0095] In 303, the gNB and WTRU may obtain a codebook by quantizing a set of precoders (for example, in Scenario 1 or Scenario 2 as described herein).

[0096] In an example (e.g., Scenario 3 as described herein), the gNB may obtain the codebook by quantizing a set of precoders (e.g., in Case 1 as described herein). The gNB may feed the entire codebook back to the WTRU (e.g., using DCI) or upload it to a network (e.g., a cloud network) where the WTRU may download the codebook. In Case 2 (e.g., as described herein), the gNB and WTRU may obtain the codebook by quantizing a set of precoders, for example, since the WTRU is also aware of the precoders.

[0097] In an example (for instance, Scenario 4 described herein), the gNB and WTRU may obtain a codebook by quantizing a set of precoders.

[0098] In 304 (for example, inference may be performed), if, for example, the codebook is determined in the gNB and WTRU, one or more of the following steps may be performed (for example, during real-time data transmission, for example, if training is complete): The gNB may configure a CSI-RS and, for example, if the gNB wishes to perform a CSI measurement (for example, indicates) (for example, then), it may send a CSI-RS to the WTRU. The WTRU may estimate the channel and feed back the PMI from the codebook (for example, in the first TxOP). The WTRU may feed back the differential PMI (for example, differential PMI only) if, for example, the reporting configuration has been set to PMI by the gNB (for example, in a subsequent TxOP). The differential PMI may be the difference between the previous PMI and the currently selected PMI.

[0099] In 305, the gNB may transmit data using the PMI proposed by the WTRU (e.g., the PMI provided feedback by the WTRU).

[0100] In 306, the WTRU may request precoder codebook retraining from the gNB (for example, to update the WTRU-gNB codebook entry) if the BER fails to meet a threshold over a certain number of iterations. In the example, the gNB may request retraining if MU-MIMO is considered (for example, in the update or at a later stage).

[0101] In 307, the gNB may check and determine that the network transmission parameters or the number of WTRUs in the network requesting retraining meet a pre-configured value for retraining (e.g., if required). This pre-configured value may be the BER, the total network rate, or the number of WTRUs requesting retraining.

[0102] In 308, the gNB may send an indication to the WTRU, for example, whether the gNB is configuring the WTRU for retraining in the next TxOP, or whether the gNB is continuing to transmit data.

[0103] In 309, the WTRU may update its precoder predictive model parameters (e.g., ML parameters) to obtain the precoder, for example, if the intention to retrain is received from the gNB. For example, the WTRU may update its precoder predictive model parameters using the training samples. The WTRU may send a differential precoder (e.g., differential precoder only) to the gNB to reduce overhead, for example, if the precoder is obtained in the WTRU. For example, if the previously selected PMI was 6 and the currently selected PMI is 5, the difference between the two PMIs (e.g., 6-5=1 or 5-6=-1) may be sent. The gNB and WTRU may update the codebook entries.

[0104] If an intention to continue data transmission is received, the WTRU can revert to conventional (e.g., classical) PMI for data transmission. For example, conventional PMI could be existing codebook-based PMI feedback (such as in 5G NR).

[0105] WTRU can revert to existing codebook-based PMI feedback (e.g., as in 5G NR) if online training / retraining to update (one or more) model parameters does not converge (e.g., after a pre-configured number of iterations or within a pre-configured duration).

[0106] Figure 4 shows an example of a data-driven codebook during training of a DRL from the perspective of WTRU, where one or more illustrated actions may be performed. The convergence criterion for the DRL (AI / ML model) may be that the reward (e.g., BER) reaches its maximum value with respect to the DRL and does not change with more iterations.

[0107] Figure 5 shows an example of a data-driven codebook during DRL training from a gNB perspective, where one or more illustrated actions may be performed.

[0108] Figure 6 shows an exemplary signaling procedure during training between a gNB and a WTRU in an exemplary data-driven codebook when an AI / ML model (DRL) is employed in the WTRU. One or more illustrated actions may be performed. As shown in Figure 6, the WTRU may transmit an SRS to the base station (e.g., to establish WTRU-specific precoder action space information with the base station). As shown in Figure 6, the WTRU may receive precoder space selection information (e.g., determine the precoder space selection information). The precoder space selection information may include indices of contiguous space regions. The precoder space selection information may include WTRU-specific precoder action space information. As shown in Figure 6, the WTRU may receive CSI-RS and data (e.g., the first CSI-RS) from the base station (e.g., the gNB). As shown in Figure 6, the WTRU may feed back precoders to the base station (for example, by selecting a first precoder from WTRU-specific precoder action spatial information and determining the reward value for the first precoder using a precoder prediction model). As shown in Figure 6, the WTRU may check the convergence of the precoder predictor model (e.g., a DRL model) (e.g., based on the reward value). As shown in Figure 6, the WTRU may determine that the precoder predictor model has converged (e.g., based on the reward value, e.g., a condition is met). As shown in Figure 6, the WTRU may indicate the convergence of the precoder predictor model to the base station (e.g., using the reward value and the precoder associated with the reward value).

[0109] Figure 7 shows an example of message exchange from the perspective of WTRU during real-time data transmission and feedback, and one or more illustrated actions may be performed.

[0110] Figure 8 shows an exemplary message exchange between a gNB and a WTRU during real-time data transmission, and one or more illustrated actions may be performed. The differential PMI may be the difference between the PMI in the previous TxOP and the PMI in the current TxOP. For example, if the previously selected PMI was 6 and the currently selected PMI is 5, then the difference between the two PMIs (e.g., 6-5=1 or 5-6=-1) may be transmitted.

[0111] Figure 9 shows an exemplary signaling procedure during training between the gNB and the WTRU of the data-driven codebook when an AI / ML model (DRL) is employed in the gNB. One or more of the illustrated actions may be performed.

[0112] Figure 10 shows an exemplary signaling procedure during training between a data-driven codebook gNB and WTRU when an AI / ML model (DRL) is mirrored in the gNB and WTRU. One or more illustrated actions may be performed.

[0113] Figure 11 shows an exemplary flow for determining a precoder using the precoder prediction model described herein, and one or more of the illustrated features may be performed. As shown in Figure 11, precoder spatial selection information may be determined at 1101. The precoder spatial selection information may include WTRU-specific precoder action spatial information. A first CSI-RS may be received (e.g., from a base station) as shown at 1102 in Figure 11. A first precoder may be selected as shown at 1103 in Figure 11. The first precoder may be selected from WTRU-specific precoder action spatial information. A first reward value may be determined for the first precoder as shown at 1104 in Figure 11. The first reward value may be determined, for example, using the precoder prediction model. It may be determined whether a condition is met. For example, the condition may be whether the precoder prediction model has converged. Whether the condition is met may be determined, for example, based on a first reward value (for example, whether the precoder prediction model has converged may be determined based on a first reward value). (For example, if the condition is met based on a first reward value) an instruction may be sent to the base station. The instruction may indicate a first precoder and a first reward value (for example, if the condition is met based on a first reward value). The instruction may indicate that the condition is met.

[0114] Although the features and elements described above are described in specific combinations, each feature or element may be used alone without other features and elements of the preferred embodiment, or in various combinations with or without other features and elements.

[0115] While the implementations described herein may take into account 3GPP-specific protocols, it will be understood that the implementations described herein are not limited to this scenario and may be applicable to other wireless systems. For example, while the solutions described herein take into account LTE, LTE-A, New Radio (NR), or 5G-specific protocols, it will be understood that the solutions described herein are not limited to this scenario and may be further applicable to other wireless systems. For example, while systems have been described with reference to 3GPP, 5G, and / or NR network layers, the envisioned embodiments extend beyond implementations using specific network layer technologies. Similarly, potential implementations encompass all types of service layer architectures, systems, and embodiments. The technologies described herein can be applied independently and / or used in combination with other resource configuration technologies.

[0116] The processes described herein may be implemented in computer programs, software, and / or firmware embedded in computer-readable media for execution by a computer and / or processor. Examples of computer-readable media include, but are not limited to, electronic signals (transmitted via wired and / or wireless connections) and / or 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, internal hard disks, and removable disks, as well as magnetic media, magneto-optical media, and / or optical media such as compact disc (CD)-ROM discs and / or digital versatile disks (DVDs). A processor associated with the software may be used to implement radio frequency transceivers for use in WTRUs, terminals, base stations, RNCs, and / or any host computer.

[0117] It is understood that entities performing the processes described herein may be logical entities that can be implemented in the form of software (e.g., computer executable instructions) stored in the memory of a mobile device, a network node, or a computer system and executed on its processor. That is, the process may be implemented in the form of software (e.g., computer executable instructions) stored in the memory of a mobile device and / or a network node such as a node or computer system, and when these computer executable instructions are executed by the node's processor, they perform the process discussed. It is also understood that any transmit and receive processes shown in the drawings may be performed by the node's communication circuitry under the control of the node's processor and the computer executable instructions (e.g., software) it executes.

[0118] The various technologies described herein may be implemented in relation to hardware, software, or a combination of both as appropriate. Therefore, implementations and apparatus of the subject matter described herein, or particular aspects or parts thereof, may take the form of program code (e.g., instructions) embodied in tangible media, including any other machine-readable storage medium, such that when the program code is loaded and executed on a machine, such as a computer, that machine becomes an apparatus for carrying out the subject matter described herein. Where the program code is stored on a medium, it may be stored on one or more media that collectively carry out the actions, i.e., one or more media together contain the code for carrying out the actions, provided that if two or more single media exist, it is not necessary to store specific parts of the code on specific media. In the case of program code execution on a programmable device, the computing device generally includes a processor, a processor-readable storage medium (including volatile and non-volatile memory and / or memory elements), at least one input device, and at least one output device. One or more programs may implement or utilize processes described in relation to the subject matter described herein, for example, through the use of APIs, reusable controls, etc. Such programs are preferably implemented in a high-level procedural or object-oriented programming language for communication with a computer system. However, the program may be implemented in assembly language or machine code as needed. In either case, the language may be a compiled language or an interpreted language, and may be combined with a hardware implementation.

[0119] While exemplary embodiments may refer to utilizing aspects of the subject matter described herein in the environment of one or more standalone computing systems, the subject matter described herein is not limited thereto and may rather be implemented in connection with any computing environment, such as a network or distributed computing environment. Furthermore, aspects of the subject matter described herein may be implemented in or across multiple processing chips or devices, and storage may similarly be affected across multiple devices. Such devices may include personal computers, network servers, handheld devices, supercomputers, or computers integrated into other systems such as automobiles and airplanes.

[0120] In describing preferred embodiments of the subject matter of this disclosure, certain terms are used for clarity, as illustrated in the figures. However, it should be understood that the claimed subject matter is not intended to be limited to the specific terms thus selected, and each particular element includes all technical equivalents that operate in a similar manner to achieve a similar purpose.

Claims

1. A wireless transmitter / receiver unit (WTRU), A processor is provided, and the processor is Determine the precoder space selection information, which includes WTRU-specific precoder action space information. The base station receives the first channel status information reference signal (CSI-RS), A first precoder is selected from the WTRU-specific precoder action spatial information. Using a precoder prediction model, determine a first reward value for the first precoder, which is associated with the first CSI-RS. Based on the first reward value, determine whether the condition is met. A wireless transmit / receive unit (WTRU) is configured to transmit an instruction to the base station based on the determination of whether the conditions are met based on the first reward value, wherein the instruction indicates precoder information and reward value information.

2. The WTRU according to claim 1, wherein the determination of whether the condition is met based on the first reward value includes a determination of whether the precoder prediction model has converged based on the first reward value, and the determination that the condition is met based on the first reward value is further based on the determination that the precoder prediction model has converged based on the first reward value.

3. The WTRU according to claim 1, wherein the precoder prediction model is a machine learning model.

4. The aforementioned processor, The WTRU according to claim 1, further configured to transmit a sounding reference signal (SRS) to the base station, wherein the SRS is associated with establishing WTRU-specific precoder action spatial information with the base station.

5. The WTRU according to claim 1, wherein the first reward value is associated with at least one of a data rate or a bit error rate.

6. The aforementioned processor, Based on the first reward value, it is determined that the above condition is not met. Based on the determination that the conditions are not met based on the first reward value, a second precoder is selected from the WTRU-specific precoder action space information. Using the precoder prediction model, a second reward value for the second precoder, which is associated with the first CSI-RS, is determined. The WTRU according to claim 1, further configured to determine whether the condition is met based on the second reward value, wherein based on the determination that the condition is met based on the second reward value, the precoder information indicates the second precoder, the reward value information indicates the second reward value, and the instruction indicates that the condition is met.

7. The WTRU according to claim 1, wherein, based on the determination that the condition is met based on the first reward value, the precoder information indicates the first precoder, the reward value information indicates the first reward value, and the instruction further indicates that the condition is met.

8. The aforementioned processor, The second CSI-RS is received from the aforementioned base station. Using the second CSI-RS and the precoder prediction model described above, the predicted precoder is determined. The WTRU according to claim 1, further configured to generate a codebook based on the first precoder and the predicted precoder.

9. It is a method, Determining precoder space selection information that includes WTRU-specific precoder action space information, Receiving a first channel status information reference signal (CSI-RS) from the base station, Selecting a first precoder from the WTRU-specific precoder action spatial information, Using a precoder prediction model, determine a first reward value for the first precoder, which is associated with the first CSI-RS. To determine whether the condition is met based on the first reward value, A method comprising: transmitting an instruction to the base station based on a determination that the conditions are met based on the first reward value, wherein the instruction indicates precoder information and reward value information.

10. The method according to claim 9, wherein the determination of whether the condition is met based on the first reward value includes a determination of whether the precoder prediction model has converged based on the first reward value, and the determination that the condition is met based on the first reward value is further based on the determination that the precoder prediction model has converged based on the first reward value.

11. The method according to claim 9, wherein the precoder prediction model is a machine learning model.

12. The method described above is The method according to claim 9, further comprising transmitting a sounding reference signal (SRS) to the base station, wherein the SRS is associated with establishing precoder action spatial information specific to the base station and the WTRU.

13. The method according to claim 9, wherein the first reward value is associated with at least one of a data rate or a bit error rate.

14. The method described above is To determine that the above condition is not met based on the first reward value, Based on the determination that the conditions are not met based on the first reward value, a second precoder is selected from the WTRU-specific precoder action space information, Using the precoder prediction model, determine a second reward value for the second precoder, which is associated with the first CSI-RS. The method according to claim 9, further comprising determining that the condition is met based on the second reward value, wherein, based on the determination that the condition is met based on the second reward value, the precoder information indicates the second precoder, the reward value information indicates the second reward value, and the instruction indicates that the condition is met.

15. The method according to claim 9, wherein, based on a determination that the condition is met based on the first reward value, the precoder information indicates the first precoder, the reward value information indicates the first reward value, and the instruction further indicates that the condition is met.

16. The method described above is Receiving a second CSI-RS from the aforementioned base station, The predicted precoder is determined using the second CSI-RS and the precoder prediction model described above. The method according to claim 9, further comprising generating a codebook based on the first precoder and the predicted precoder.

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