Joint precoding, beamforming and modulation based on reconfigurable smart / holographic surfaces

Abstract

A wireless transmit / receive unit (WTRU) may receive a channel state information reference signal (CSI-RS) from a transmitter (e.g., via a reconfigurable smart surface (RIS)). The transmitter may be associated with the RIS. The WTRU may determine channel information (e.g., channel vector information) associated with a first subset of elements of the RIS based on the CSI-RS. The WTRU may determine channel information (e.g., channel vector information) associated with a second subset of elements of the RIS based on the channel information associated with the first subset of elements of the RIS. The WTRU may generate a CSI reporting parameter based on the channel information associated with the second subset of the elements of the RIS. The WTRU may transmit the CSI reporting parameter. The WTRU may generate the CSI reporting parameter using a channel matrix associated with the RIS. The CSI reporting parameter may be a virtual CSI reporting parameter.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of Provisional U.S. Patent Application No. 63 / 402,548 filed on August 31, 2022, Provisional U.S. Patent Application No. 63 / 429,345 filed on December 1, 2022, and Provisional U.S. Patent Application No. 63 / 526,234 filed on July 12, 2023, the disclosures of which are incorporated herein by reference in their entirety. Background Art

[0003] Mobile communications using wireless communications continue to evolve. The fifth generation of mobile communications radio access technology (RAT) may be referred to as 5G New Radio (NR). The previous generation (legacy) mobile communications RAT may be, for example, fourth generation (4G) long term evolution (LTE). Wireless communication devices may establish communications with other devices and data networks, for example, via access networks such as radio access networks (RAN). Summary of the invention

[0004] Disclosed herein are systems, methods, and means associated with generating CSI reporting parameters based on channel information associated with a reconfigurable smart surface (RIS).

[0005] In an example, a wireless transmit / receive unit (WTRU) may receive a channel state information reference signal (CSI-RS) from a transmitter (e.g., via a reconfigurable smart surface (RIS)). The transmitter (e.g., a RIS-based transmitter) may be associated with the RIS. The WTRU may determine channel information (e.g., channel vector information) associated with a first subset of elements of the RIS based on the CSI-RS. The WTRU may determine channel information (e.g., channel vector information) associated with a second subset of elements of the RIS based on the channel information associated with the first subset of elements of the RIS. The WTRU may generate CSI reporting parameters based on the channel information associated with the second subset of elements of the RIS. The WTRU may transmit the CSI reporting parameters.

[0006] The WTRU may generate the CSI reporting parameters using a channel matrix associated with the RIS. In an example, the WTRU may determine the channel matrix associated with the RIS, for example, based on the channel information associated with the first subset of elements of the RIS and / or the channel information associated with the second subset of elements of the RIS. The channel matrix may include the channel information associated with the first subset of elements of the RIS and / or the channel information associated with the second subset of elements of the RIS. The WTRU may generate the CSI reporting parameters using the channel matrix associated with the RIS.

[0007] The CSI reporting parameters may be virtual CSI reporting parameters. In an example, the WTRU may receive configuration information associated with the RIS. The configuration information associated with the RIS may indicate a configuration associated with the first subset of elements of the RIS and / or a configuration associated with the second subset of elements of the RIS. The WTRU may determine a first channel matrix based on the channel information associated with the first subset of elements of the RIS. The WTRU may determine a second channel matrix based on the first channel matrix and the configuration information. The second channel matrix may include the channel information associated with the first subset of elements of the RIS and the channel information associated with the second subset of elements of the RIS. The WTRU may use the second channel matrix to generate the virtual CSI reporting parameters. In some examples, the first channel matrix may include first channel matrix coefficients, which indicate channel information (e.g., channel vector information) associated with elements in the first subset of elements of the RIS. The second channel matrix may include the first channel matrix coefficients and second channel matrix coefficients indicating channel information (eg, channel vector information) associated with elements in the second subset of elements of the RIS.

[0008] In an example, the configuration information associated with the RIS may indicate active elements of the RIS and / or non-active elements of the RIS. The CSI-RS used by the WTRU to determine the channel information associated with the first subset of elements of the RIS may be associated with the active elements of the RIS. For example, the configuration information associated with the RIS may indicate that the first subset of elements includes one or more active elements of the RIS (e.g., including the active element associated with the CSI-RS) and / or the second subset of elements includes one or more non-active elements of the RIS.

[0009] The WTRU may determine another CSI reporting parameter based on a channel measurement. In an example, the WTRU may perform the channel measurement based on one or more CSI-RS. The channel measurement may be limited to the first subset of elements of the RIS (e.g., the channel measurement may be limited to one or more CSI-RS associated with the active element of the RIS). The WTRU may use the channel measurement to determine, for example, CSI reporting parameters other than the virtual CSI reporting parameter and / or determine the channel information associated with the first subset of elements of the RIS. In an example, the WTRU may determine the virtual channel reporting parameter and / or another channel reporting parameter, and transmit at least one of the virtual channel reporting parameter and / or another channel reporting parameter.

[0010] The WTRU may also generate the CSI reporting parameters based on block partitioning information associated with the RIS. In an example, the WTRU may receive the block partitioning information associated with the RIS (e.g., in the configuration information associated with the RIS). The block partitioning information may indicate that the RIS includes a first block of elements and a second block of elements. The first block of elements may include the first subset of elements and the second subset of elements. The first subset of elements may include active elements associated with the first block of elements, and the second subset of elements may include non-active elements associated with the first block of elements. The CSI reporting parameters generated by the WTRU based on the block partitioning information may be associated with the first block of elements.

[0011] The WTRU may transmit and / or receive RIS-based transmissions. In an example, the WTRU may receive a request to communicate using RIS-based transmissions. For example, after the WTRU transmits the CSI reporting parameters to a base station, the WTRU may receive an indication of one or more transmit ports. The WTRU may decode the RIS-based transmission based on the indication of the one or more transmit ports. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1A is a system diagram illustrating an example communication system in which one or more disclosed embodiments may be implemented.

[0013] Figure 1B is an example of a method that can be used according to an embodiment of the present invention. Figure 1A A system diagram of an example wireless transmit / receive unit (WTRU) for use within an illustrated communication system.

[0014] Figure 1C is an example of a method that can be used according to an embodiment of the present invention. Figure 1A System diagram of an example Radio Access Network (RAN) and an example Core Network (CN) for use within an illustrated communication system.

[0015] Figure 1D is an example of a method that can be used according to an embodiment of the present invention. Figure 1A System diagram of another example RAN and another example CN for use within the illustrated communication system.

[0016] Figure 2 An example architecture associated with RIS-based information transfer is shown.

[0017] Figure 3 Examples of hybrid beamforming architectures and ports (eg, antenna ports and / or logical antenna ports) are shown.

[0018] Figure 4 An example of an antenna port configuration of (N1, N2) that may be used in one or more examples as described herein is shown: Figure 4 (a) shows a 16x1 configuration; Figure 4 (b) shows an 8x2 configuration; Figure 4 (c) shows a 4x4 configuration.

[0019] Figure 5 Examples of in-phase and quadrature-phase (IQ) modulators are shown.

[0020] Figure 6 An example of a direct conversion / zero IF architecture is shown.

[0021] Figure 7 An example of a RIS-based transmitter (eg, a RIS-based multi-user transmitter) is shown.

[0022] Figure 8 An example of an RHS-based transmitter (eg, an RHS-based multi-user transmitter) is shown.

[0023] Fig. 9 The reflection coefficient (eg, the reflection coefficient φ n ,in ) and configurable load impedance (e.g., configurable load impedance in )

[0024] Fig.10 An example RIS / RHS-based transmission (eg, an example RIS / RHS-based multi-user transmission) is shown.

[0025] Fig.11 An example RIS / RHS controller is shown (eg, a RIS / RHS controller that uses phase and amplitude information of x to tune RIS / RHS elements).

[0026] Fig.12An example block diagram of CP-OFDM is shown.

[0027] Fig.13 An example of theoretical and simulation comparison of spectral efficiency versus transmit power for MIMO in a LoS channel (eg, conventional MIMO) and a RIS-based single RF downlink information transfer system in a Rayleigh channel is shown.

[0028] Fig.14 An example of theoretical and simulation comparison of symbol error probability versus transmit power Es for MIMO in a LoS channel (eg, conventional MIMO) and a RIS-based single RF downlink information transfer system in a Rayleigh channel is shown.

[0029] Fig.15 The number of RF chains (N) in some MIMO systems (eg, conventional MIMO systems) is shown. RF ) and the number of RIS elements (N) in a RIS-assisted single RF information transfer scheme while achieving the same traversal rate.

[0030] Fig.16 shows (for example, when considering different power allocation techniques) and the rate R sum , minimum rate R min , geometric mean rate R GM Example of simulation comparison with average received SINRρ.

[0031] Fig.17 The sum rate R is shown for different channel correlation values ​​(eg, when the sum rate is calculated using the maximization sum rate technique, the minimum rate is calculated using the maximization minimum rate technique, and the geometric mean rate is calculated using the maximization geometric mean rate technique). sum , minimum rate R min , geometric mean rate R GM Example of simulation comparison with average received SINRρ.

[0032] Fig.18 The sum rate R for different power allocation techniques (eg, in the case of average received SINRρ=-25dB) is shown. sum , minimum rate R min , geometric mean rate R GM Example of simulation comparison with the number N of RIS elements.

[0033] Fig.19 1 shows the symbol error probability P for various power allocation techniques (eg, the three power allocation techniques described in one or more examples herein). e Example of simulation comparison with average received SINRρ.

[0034] Fig. 20 An example of comparison of BER performance with average received SNR p using different modulation schemes (eg, where the number of users K=4 and the number of RIS elements N=256) is shown.

[0035] Fig.21 An example of comparison of BER performance with average received SNR p for different numbers of users K (eg, for a case where the number of RIS elements N=256 and the modulation schemes are 16-PSK and 16-QAM, respectively) is shown.

[0036] Fig. 22 An example of comparison of BER performance and average received SNR p for different numbers N of RIS elements (eg, for the number of users K=4 and the modulation schemes 16-PSK and 16-QAM, respectively) is shown.

[0037] Fig.23 An example of BER performance versus average received SNRρ in a RIS-based transmitter and a MIMO example (eg, conventional massive MIMO) is shown, where the number of users is K=1 and the modulation schemes are 16-PSK and 16-QAM, respectively.

[0038] Fig.24 An example of partitioning the RIS / RHS array into blocks for CSI-RS transmission is shown.

[0039] Fig.25 Examples of determining and reporting a CSI report and / or a V-CSI report are shown.

[0040] Fig.26 An example of port allocation for use in association with RIS-based routing is shown. DETAILED DESCRIPTION

[0041] 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, and filter bank multi-carrier (FBMC), etc.

[0042] 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 UE 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 a user equipment (WTRU), 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.

[0043] 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 base transceiver stations (BTS), Node Bs, Code Bs, Home Node Bs, Home eNode Bs, gNBs, NR Node Bs, site controllers, access points (APs), wireless routers, and the like. While the base stations 114a, 114b are each depicted as a single element, it will be appreciated that the base stations 114a, 114b may include any number of interconnected base stations and / or network elements.

[0044] 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 base station controllers (BSC), radio network controllers (RNC), relay nodes, etc. Base station 114a and / or 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 a licensed spectrum and an unlicensed spectrum. 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, the cell associated with base station 114a may be divided into three sectors. Therefore, in one embodiment, base station 114a may include three transceivers, i.e., one transceiver for each sector of the cell. In an embodiment, 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.

[0045] 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).

[0046] 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, and SC-FDMA, among others. 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 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 (DL) Packet Access (HSDPA) and / or High Speed ​​UL Packet Access (HSUPA).

[0047] 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).

[0048] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as NR radio access, which may establish the air interface 116 using New Radio (NR).

[0049] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement multiple radio access technologies. For example, the base station 114a and the WTRUs 102a, 102b, 102c may together implement LTE radio access and NR radio access, 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).

[0050] 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, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile Communications (GSM), Enhanced Data rates for GSM Evolution (EDGE), and GSM EDGE (GERAN).

[0051] 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 utilize any suitable RAT to facilitate wireless connectivity in local areas such as commercial venues, homes, vehicles, campuses, industrial facilities, sky corridors (e.g., for use by drones), and roads. In one embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology (such as IEEE 802.11) to establish a wireless local area network (WLAN). In an embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology (such as IEEE 802.15) to establish a wireless personal area network (WPAN). In yet another embodiment, the base station 114b and the WTRUs 102c, 102d may utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.) to establish a picocell or a femtocell. As 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.

[0052] 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 and video, 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. 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. 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, CDMA2000, WiMAX, E-UTRA, or WiFi radio technology.

[0053] The CN 106 / 115 may also act 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.

[0054] 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.

[0055] 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.

[0056] 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) and 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.

[0057] The send / receive element 122 may be configured to send a signal to a base station (e.g., base station 114a) or receive a signal from a base station via an air interface 116. For example, in one embodiment, the send / receive element 122 may be an antenna configured to send and / or receive an RF signal. In an embodiment, the send / receive element 122 may be a transmitter / detector configured to send and / or receive, for example, an IR, UV, or visible light signal. In another embodiment, the send / receive element 122 may be configured to send and / or receive both an RF signal and an optical signal. It should be understood that the send / receive element 122 may be configured to send and / or receive any combination of wireless signals.

[0058] Although the transmit / receive element 122 Figure 1B Although depicted as a single element in the figure, 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.

[0059] 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 for enabling the WTRU 102 to communicate via multiple RATs, such as NR and IEEE 802.11.

[0060] The processor 118 of the WTRU 102 may be coupled to and may receive user input data from 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). 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, and a secure digital (SD) memory card, among others. 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).

[0061] 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.

[0062] 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.

[0063] 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, FM radio unit, digital music player, media player, video game player module, Internet browser, virtual reality and / or augmented reality (VR / AR) device and activity tracker, etc. Peripheral device 138 may include one or more sensors, which may be one or more of the following: gyroscope, accelerometer, Hall effect sensor, magnetometer, orientation sensor, proximity sensor, temperature sensor, time sensor; geolocation sensor; altimeter, light sensor, touch sensor, magnetometer, barometer, gesture sensor, biometric sensor and / or humidity sensor.

[0064] 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 UL (e.g., for transmission) and downlink (e.g., for reception)) may be concurrent and / or simultaneous. The full-duplex radio may include an interference management unit for reducing and / or substantially eliminating self-interference via hardware (e.g., a choke) or via signal processing performed by a processor (e.g., a separate processor (not shown) or via the processor 118). In one embodiment, the WRTU 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 UL (e.g., for transmission) or downlink (e.g., for reception)) may be concurrent and / or simultaneous.

[0065] 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.

[0066] 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.

[0067] Each of the evolved Node Bs 160a, 160b, 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, and scheduling of users in the UL and / or DL, among other things. Figure 1C As shown, the eNode-Bs 160a, 160b, 160c may communicate with one another via an X2 interface.

[0068] 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 are 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 a CN operator.

[0069] The MME 162 may be connected to each of the evolved Node-Bs 160a, 160b, 160c in the RAN 104 via an S1 interface and may serve as a control node. For example, the MME 162 may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, bearer activation / deactivation, and selecting a particular serving gateway during an initial attach of the WTRUs 102a, 102b, 102c. 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.

[0070] 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 an inter-evolved Node-B handover, triggering paging when DL data is available for the WTRUs 102a, 102b, 102c, and managing and storing the context of the WTRUs 102a, 102b, 102c.

[0071] 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.

[0072] 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.

[0073] Although the WTRU Figures 1A to 1D Although described as wireless terminals, it is contemplated that in certain representative embodiments, such terminals may (eg, temporarily or permanently) use a wired communication interface with a communication network.

[0074] In a representative embodiment, the other network 112 may be a WLAN.

[0075] A WLAN in infrastructure basic service set (BSS) mode may have an access point (AP) for a BSS and one or more stations (STAs) 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 traffic to and / or out of the BSS. Traffic originating from outside the BSS and destined for the STA may be reached by the AP and may be delivered to the STA. Traffic originating from the STA and destined for a target outside the BSS may be transmitted to the AP to be delivered to the corresponding target. Traffic between STAs within the BSS may be transmitted by the AP, for example, wherein the source STA may transmit traffic to the AP, and the AP may deliver traffic to the destination STA. Traffic between STAs within the BSS may be considered and / or referred to as point-to-point traffic. Point-to-point traffic 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.

[0076] When using the 802.11ac infrastructure operation mode or a similar operation 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 20 MHz 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 sense the primary channel. If the primary channel is sensed / detected and / or determined to be busy by a particular STA, the particular STA may back off. One STA (e.g., only one station) may transmit at any given time in a given BSS.

[0077] High throughput (HT) STAs may communicate using a 40 MHz wide channel (eg, via a combination of a primary 20 MHz channel and adjacent or non-adjacent 20 MHz channels) to form a 40 MHz wide channel.

[0078] 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 the data can be sent by sending STA. At the receiver of the receiving STA, the above-mentioned operation for 80+80 configuration can be reversed, and the combined data can be transmitted to the medium access control (MAC).

[0079] 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 may 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).

[0080] 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 band may be considered busy even if most of the band remains idle and may be available.

[0081] 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.

[0082] Figure 1D 1 is a system diagram illustrating the RAN 113 and the CN 115 in accordance with an 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.

[0083] The RAN 113 may include gNBs 180a, 180b, 180c, though it will be appreciated that the RAN 113 may include any number of gNBs while remaining consistent with an embodiment. The gNBs 180a, 180b, 180c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In one embodiment, the gNBs 180a, 180b, 180c may implement MIMO technology. For example, 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, the gNB 180a may transmit multiple component carriers to the WTRU 102a (not shown). A subset of these component carriers may be on an unlicensed spectrum, while the remaining component carriers may be on a licensed spectrum. In an embodiment, the gNBs 180a, 180b, 180c may implement coordinated multi-point (CoMP) technology. For example, the WTRU 102a may receive coordinated transmissions from the gNB 180a and the gNB 180b (and / or the gNB 180c).

[0084] 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 transmit time intervals (TTIs) of varying or scalable lengths (e.g., containing varying numbers of OFDM symbols and / or varying absolute time lengths over time).

[0085] 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 anchor points. 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 eNodeB 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 eNodeBs 160a, 160b, 160c substantially simultaneously. In a non-standalone configuration, the eNodeB 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.

[0086] 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 UL and / or 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. Figure 1D As shown, gNBs 180a, 180b, and 180c may communicate with each other via an Xn interface.

[0087] Figure 1DThe illustrated CN 115 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 the CN operator.

[0088] 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 mobile broadband (eMBB) access, and / or services for machine type communication (MTC) access, etc. The AMF 162 may provide a control plane function for switching between the RAN 113 and other RANs (not shown) that employ other radio technologies, such as LTE, LTE-A, LTE-A Pro, and / or non-3GPP access technologies, such as WiFi.

[0089] 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.

[0090] 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, and providing mobility anchoring, etc.

[0091] The CN 115 may facilitate communications with other networks. For example, the CN 115 may include or may communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that acts as an interface between the CN 115 and the PSTN 108. In addition, the CN 115 may provide the WTRUs 102a, 102b, 102c with access to 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 local data networks (DNs) 185a, 185b via the UPF 184a, 184b via the N3 interface to the UPF 184a, 184b and the N6 interface between the UPF 184a, 184b and the DN 185a, 185b.

[0092] 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-d, base station 114a-b, evolved Node B 160a-c, MME 162, SGW 164, PGW 166, gNB 180a-c, AMF182a-b, UPF 184a-b, SMF 183a-b, DN 185a-b and / or any other device described herein. The simulation device may be one or more devices configured to emulate 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.

[0093] The simulation device may 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 may 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 may 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 may be directly coupled to another device for testing purposes and / or may use over-the-air wireless communications to perform testing.

[0094] 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 laboratory 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.

[0095] Disclosed herein are systems, methods, and means associated with joint precoding, beamforming, and modulation based on a reconfigurable smart surface (RIS) / reconfigurable holographic surface (RHS). Joint multi-user precoding and modulation based on RIS / RHS can be provided, which is processed digitally and deployed in a non-digital manner (e.g., using RIS / RHS elements). The transmission scheme can allow IQ-based constellations (e.g., any constellation based on in-phase and quadrature phase (IQ), such as quadrature amplitude modulation (QAM) and / or amplitude and phase shift keying (APSK)) and OFDM transmission without peak-to-average power ratio (PAPR). The power allocation of each user RIS / RHS element can be used with optimization techniques. For example, unlike the classic hybrid beamforming architecture that is limited by the transceiver unit (TXRU), OFDM transmission can be unrestricted by the number of resources. In one or more examples herein, for example, orthogonal frequency division multiplexing (OFDM) modulation with per-subcarrier precoding may be used to achieve bit error rate (BER) performance and average received signal-to-noise ratio (SNR) for quadrature amplitude modulation (QAM) and phase shift keying (PSK) modulation. In an example, a WTRU may receive symbols to send to a device and / or configure an element (e.g., a RIS / RHS element) to send a symbol (e.g., a QAM symbol). A corresponding phase shift and / or a corresponding amplitude may be set for a corresponding element. A total amplitude associated with an element may be related to a scaling factor associated with the element.

[0096] Dynamic resource allocation may be performed for RIS-based transmissions. A wireless transmit / receive unit (WTRU) may receive configuration information that may indicate one or more of the following: a maximum number of supported channel state information reference signal (CSI-RS) and / or demodulation reference signal (DMRS) ports; port resources (e.g., antenna port resources in the time domain and / or frequency domain). For example, the WTRU may estimate a full array of ports (e.g., virtual antenna ports) based on the Tx CSI-RS ports to calculate and / or report virtual CSI (e.g., including one or more of a virtual channel quality indication (V-CQI), a virtual precoding matrix indicator (V-PMI), a virtual rank indicator (V-RI), a virtual layer indicator (V-LI), etc.). The WTRU may be dynamically configured for physical downlink shared channel (PDSCH) transmissions with DMRS ports.

[0097] Disclosed herein are systems, methods, and means associated with generating CSI reporting parameters based on channel information associated with a reconfigurable smart surface (RIS).

[0098] In an example, a wireless transmit / receive unit (WTRU) may receive a channel state information reference signal (CSI-RS) from a transmitter (e.g., via a reconfigurable intelligent surface (RIS)). The transmitter may be associated with the RIS. The WTRU may determine channel information (e.g., channel vector information) associated with a first subset of elements of the RIS based on the CSI-RS. The WTRU may determine channel information (e.g., channel vector information) associated with a second subset of elements of the RIS based on the channel information associated with the first subset of elements of the RIS. The WTRU may generate CSI reporting parameters based on the channel information associated with the second subset of elements of the RIS. The WTRU may transmit the CSI reporting parameters.

[0099] The WTRU may generate the CSI reporting parameters using a channel matrix associated with the RIS. In an example, the WTRU may determine the channel matrix associated with the RIS, for example, based on the channel information associated with the first subset of elements of the RIS and / or the channel information associated with the second subset of elements of the RIS. The channel matrix may include the channel information associated with the first subset of elements of the RIS and / or the channel information associated with the second subset of elements of the RIS. The WTRU may generate the CSI reporting parameters using the channel matrix associated with the RIS.

[0100] The CSI reporting parameters may be virtual CSI reporting parameters. In an example, the WTRU may receive configuration information associated with the RIS. The configuration information associated with the RIS may indicate a configuration associated with the first subset of elements of the RIS and / or a configuration associated with the second subset of elements of the RIS. The WTRU may determine a first channel matrix based on the channel information associated with the first subset of elements of the RIS. The WTRU may determine a second channel matrix based on the first channel matrix and the configuration information. The second channel matrix may include the channel information associated with the first subset of elements of the RIS and the channel information associated with the second subset of elements of the RIS. The WTRU may use the second channel matrix to generate the virtual CSI reporting parameters. In some examples, the first channel matrix may include first channel matrix coefficients, which indicate channel information (e.g., channel vector information) associated with elements in the first subset of elements of the RIS. The second channel matrix may include the first channel matrix coefficients and second channel matrix coefficients indicating channel information (eg, channel vector information) associated with elements in the second subset of elements of the RIS.

[0101] In an example, the configuration information associated with the RIS may indicate active elements of the RIS and / or non-active elements of the RIS. The CSI-RS used by the WTRU to determine the channel information associated with the first subset of elements of the RIS may be associated with the active elements of the RIS. For example, the configuration information associated with the RIS may indicate that the first subset of elements includes one or more active elements of the RIS (e.g., including the active element associated with the CSI-RS) and / or the second subset of elements includes one or more non-active elements of the RIS.

[0102] The WTRU may determine another CSI reporting parameter based on a channel measurement. In an example, the WTRU may perform the channel measurement based on one or more CSI-RS. The channel measurement may be limited to the first subset of elements of the RIS (e.g., the channel measurement may be limited to one or more CSI-RS associated with the active element of the RIS). The WTRU may use the channel measurement to determine, for example, CSI reporting parameters other than the virtual CSI reporting parameter and / or determine the channel information associated with the first subset of elements of the RIS. In an example, the WTRU may determine the virtual channel reporting parameter and / or another channel reporting parameter, and transmit at least one of the virtual channel reporting parameter and / or another channel reporting parameter.

[0103] The WTRU may also generate the CSI reporting parameters based on block partitioning information associated with the RIS. In an example, the WTRU may receive the block partitioning information associated with the RIS (e.g., in the configuration information associated with the RIS). The block partitioning information may indicate that the RIS includes a first block of elements and a second block of elements. The first block of elements may include the first subset of elements and the second subset of elements. The first subset of elements may include active elements associated with the first block of elements, and the second subset of elements may include non-active elements associated with the first block of elements. The CSI reporting parameters generated by the WTRU based on the block partitioning information may be associated with the first block of elements.

[0104] The WTRU may transmit and / or receive RIS-based transmissions. In an example, the WTRU may receive a request to communicate using RIS-based transmissions. For example, after the WTRU transmits the CSI reporting parameters to a base station, the WTRU may receive an indication of one or more transmit ports. The WTRU may decode the RIS-based transmission based on the indication of the one or more transmit ports.

[0105] Reconfigurable smart surfaces (RIS) can be used in one or more examples as described herein. RIS can be implemented in wireless communication systems. RIS can be capable of adjusting radio environmental conditions by electronically controlling the propagation of impulse signals on the surface, for example, to improve received signal strength and / or spectral efficiency. A surface (e.g., RIS) can include an array of elements (e.g., a large array of low-cost and energy-efficient elements). Elements can include metasurfaces and / or reflective arrays. In an example, the elements can be passive and / or do not require a dedicated energy source.

[0106] For example, RIS may have a range of applications in Internet of Things (IoT) networks, including one or more of the following: beamforming designed for mmWave communication systems to improve communication reliability, building physical layer security networks, providing simultaneous wireless information and energy transfer (SWIPT), or being used for localization, positioning, sensing, and mobile edge computing. RIS may be deployed (e.g., as a transmitter, e.g., associated with a RIS-based transmitter) to modulate signals, which may have applications in wireless communications (e.g., due to low hardware complexity compared to conventional massive MIMO systems). For example, in some massive MIMO systems, a large number of RF chains may be required to modulate signals, and in a RIS-assisted information transfer scheme, information may be modulated on a passive RIS by configuring the reflection coefficient of (e.g., each) element, which may be used as an energy-efficient and / or cost-effective architecture (e.g., hardware architecture).

[0107] RIS-based modulation may be described herein. Employing RIS (eg, as a transmitter, eg, associated with a RIS-based transmitter) may enable information modulation with low hardware complexity for wireless communication scenarios.

[0108] Figure 2 An example architecture associated with RIS-based information transfer is shown. Figure 2 The RIS-based information transfer architecture supporting a single user is shown in FIG. 1 , where a single RF chain can generate a signal with power E s and frequency f c The unmodulated sinusoidal carrier impinges on the N-element passive RIS. The RIS controller can convert the pre-decoded digital baseband signal x = [x1 x2 …x N ] T Converted into analog electrical signals to control the reflection coefficient of RIS elements (e.g., each RIS reflective element), including amplitude and phase shift. RIS-based information transfer systems (e.g., Figure 2 The RIS-based information transfer system shown may be associated with low hardware complexity (e.g., compared to some systems (e.g., conventional massive MIMO systems)). In some examples (e.g., conventional massive MIMO systems), baseband signals from a digital precoder may be converted to RF signals by multiple active RF chains and / or radiated from multiple transmit antennas. In the RIS-based information transfer system, one RF chain may be used to provide power to the RIS, and the pre-decoded digital baseband signal may be passively modulated on the RIS elements (e.g., in the RIS-based information transfer system, only one RF chain may be required to provide power to the RIS, and the pre-decoded digital baseband signal may be passively modulated on each RIS element, which may result in a virtual MIMO wireless communication system with relatively low hardware complexity).

[0109] In a RIS-assisted single-user information transfer system, the RIS may be powered, for example, by a single antenna with an unmodulated carrier signal, and / or information may be conveyed via controlling phase shifts of RIS elements (e.g., each passive RIS element). Given channel state information (CSI) (e.g., received from one or more users via CSI reports), the phases of the RIS elements (e.g., all RIS elements) may be coherently adjusted to maximize a received signal-to-noise ratio (SNR), wherein M levels of phase shifts may be modulated on signals reflected from the RIS elements (e.g., all RIS elements) to create an M-phase shift keying (PSK) signal constellation.

[0110] In some examples (e.g., example systems having a similar setup to a RIS-assisted single-user information transfer system), a blind access point RIS modulation scheme may be used for RIS-assisted single-user information transfer without CSI. Binary phase shifts (e.g., 0 and π) may be configured on RIS elements (e.g., all RIS elements) to create a binary phase shift keying (BPSK) constellation. The blind access point RIS modulation scheme may reduce channel estimation overhead (e.g., compared to a RIS-assisted single-user information system), and in some cases at the expense of performance loss.

[0111] The Alamouti scheme can be implemented using RIS, where a single RF unmodulated signal generator provides power to the RIS, and the RIS is divided into two blocks, where the Alamouti scheme is designed based on configuring the phase shift of the RIS elements. Transmit diversity (e.g., second order transmit diversity) can be achieved through a modulation scheme assisted by the RIS.

[0112] An index modulation scheme based on RIS can be constructed, where RIS is deployed between a single RF chain and a multi-antenna receiver. Two information transfer techniques can be used, for example, RIS-assisted spatial shift keying (SSK) and RIS-assisted spatial modulation (SM). In RIS-assisted SSK, the signal radiated from the RF chain can be unmodulated, and the information can be transmitted (for example, only) on a specific receiver antenna. The phase shift of the RIS elements (for example, each RIS element) can be configured to design beamforming from the RIS to the selected receiver antenna. In RIS-assisted SM, the signal in a single RF chain can be modulated, and the information can be transmitted via both the modulated signal on the RF chain and the selected receiver antenna. At the receiver, a greedy detector and a maximum likelihood (ML) detector can be used to recover the information.

[0113] A RIS-assisted receive quadrature reflection modulation (RIS-RQRM) scheme may be used (e.g., to increase throughput), where the RIS (e.g., the entire RIS) may be divided into two halves that create signals having an in-phase component and a quadrature component, respectively. For example, the information may be conveyed via one half of the RIS (e.g., each half) to form a beam to a specific antenna at a receiver.

[0114] For example, by implementing information modulation based on reflection coefficients of RIS elements configured to be powered by a single carrier generator, RIS-assisted modulation (eg, due to its energy-efficient and cost-effective hardware architecture) may have broad applications.

[0115] In an example, a single-user RIS-assisted PSK modulation architecture may be used, where an 8-PSK signal constellation is achieved by configuring the phase shifts of 8×32 RIS elements, thereby achieving a data rate of 6.144 Mbps at a carrier frequency of 4.25 GHz. Hardware complexity may be low (e.g., extremely low since only a single RF chain is required). There may be some performance differences from some systems (e.g., conventional active transmitters).

[0116] For example, due to the low hardware complexity of RIS, RIS can be applied to wireless communications with large apertures (e.g., UM-MIMO and holographic MIMO). For example, by introducing nonlinear modulation techniques under the constraint of constant envelope to achieve high-order modulation, quadrature amplitude modulation (QAM) can be designed based on independently controlling the amplitude and phase shift of RIS elements (e.g., each RIS element). RIS based on varactor diodes can be used for point-to-point 2×2 MIMO-QAM wireless systems. By realizing real-time RIS-based Alamutti space-time transmission, a wide range of applications of cost-effective hardware architectures and / or RIS-assisted modulation schemes can be demonstrated.

[0117] Figure 3 Examples of hybrid beamforming architectures and ports (eg, antenna ports and / or logical antenna ports) are shown. Figure 4 An example of an antenna port configuration of (N1, N2) that may be used in one or more examples as described herein is shown: Figure 4 (a) shows a 16×1 configuration; Figure 4 (b) shows an 8×2 configuration; Figure 4 (c) shows a 4×4 configuration. Hybrid beamforming architecture (e.g., Figure 3 One or more features of the hybrid beamforming architecture shown in FIG. 1 may be used in one or more examples as described herein. Various numbers of ports (e.g., various numbers of logical antenna ports used in NR) may be used in one or more examples as described herein. The number of ports (e.g., the number of logical antenna ports) P ​​may be {4, 8, 16, 32}, such as Figure 3 is used in the examples shown. Figure 3 In, N T Can be used to represent the number of antenna elements, N RF can be used to represent the number of RF chains, and dN RF (d_N RF ) can be used to indicate the total number of ports (e.g., 32).

[0118] The number of ports (e.g., logical antenna ports) can be mapped to different antenna port configurations (e.g., (N1, N2) in a single panel). An antenna configuration can be mapped to one or more ports (e.g., one or more CSI-RS ports). For example, 32 ports (e.g., assuming dual polarization and the number of dual polarization CSI-RS ports P = (2N1N2)) can be mapped to antenna configurations of (N1, N2) = (16, 1), (8, 2), and (4, 4), as shown in FIG. Figure 4 shown.

[0119] In an example, a DL transmission may be based on a non-codebook based precoding scheme. A precoder may be associated with a precoder matrix indicator (PMI) that is used by the WTRU as part of a CSI estimate based on one or more CSI-RS (e.g., a precoder may be used for a precoder matrix indicator (PMI) of the WTRU to estimate the CSI). Multiple (e.g., two) types of precoders may be supported. Multiple report types may be used (e.g., a report type associated with type I CSI and a report type associated with type IICSI). For example, a first type of precoder may be associated with a first report type associated with type I CSI, and a second type of precoder may be associated with a second report type associated with type IICSI (e.g., two types of precoders are supported, one may be type I CSI and the other may be type IICSI, respectively). For example, type I CSI (e.g., a report type with standard resolution) may be optimized for single user MIMO (SU-MIMO) transmissions with a potentially large number of layers (e.g., up to 8). For example, Type I ICSI (e.g., reporting type with high resolution) may be optimized for multi-user MIMO (MU-MIMO) transmissions (e.g., with up to 2 layers per scheduled WTRU and a total maximum of 12 layers). Type I and Type II (e.g., Type I codebook and Type II codebook, e.g., codebook-based CSI feedback) may construct and / or implement beam-selected CSI feedback from a two-dimensional (2D) DFT-based beam grid (e.g., and PSK-based in-phase combining between two polarizations). Type II (e.g., Type II codebook-based CSI feedback) may report wideband and subband amplitude information for the selected beam.

[0120] Figure 5 Examples of in-phase and quadrature-phase (IQ) modulators are shown. An IQ modulator may provide a technique for modulating data (e.g., symbols) onto an RF carrier. An IQ modulator (e.g., upconversion) may be an architecture for implementing a transmitter in a wireless application.

[0121] For example, mixers (e.g., one for in-phase and another for quadrature-phase) may be used to up-convert the in-phase and quadrature-phase signals to RF frequencies, such as Figure 5 As shown. The oscillator (VCO) signal can be split into two signals, for example, two signals of equal amplitude but with a phase difference (e.g., a phase difference of exactly 90°). The two orthogonal signals (e.g., an I-path signal and a Q-path signal) can drive the inputs of two mixers (e.g., two mixers considered as analog multipliers). The outputs of the two mixers (e.g., analog multipliers) can be added together (e.g., in a combiner block of an IQ modulator) to provide the output of the IQ modulator. The IQ modulator signal can be expressed as s(t)=I(t)cos2πf c tQ(t)sin2πf c t, where I(t) and Q(t) may be the in-phase signal and the quadrature-phase signal, respectively.

[0122] Figure 6 An example of a direct conversion / zero IF architecture is shown. One or more features of direct conversion and zero intermediate frequency (IF) architectures may be used in one or more examples as described herein. Direct conversion may include, for example, directly down-converting an RF signal to a baseband (BB) signal or vice versa without an intermediate frequency stage (e.g., any intermediate frequency stage), and in an example, direct conversion may be referred to as a zero IF architecture. When the oscillator is phase-locked to the carrier of the received signal, the direct conversion receiver may be referred to as a homodyne receiver. The direct conversion architecture may have one or more features. For example, as Figure 6 As shown, a direct conversion receiver may have no intermediate RF (eg, IF), and filtering (eg, all filtering) may be performed at baseband, and in an example, analog filtering used in a zero IF architecture may be alleviated.

[0123] In some examples, a massive MIMO transmitter (e.g., a conventional massive MIMO transmitter) may require a large number of end-to-end RF chains to transmit to multiple users using multiple antenna ports and / or multiple layers, which may result in high hardware complexity and / or high power consumption (e.g., which may be intolerable for a massive MIMO implementation). These transmitters may be employed using three architectures (analog beamforming, digital beamforming, and / or hybrid beamforming). Analog beamforming may be cost-effective and may experience beam deflection and / or may be limited to a single beam in some examples. Digital beamforming may allow control of antenna elements (e.g., full control of each antenna element), and in some examples, may require a single transceiver unit (TXRU) for (e.g., each) antenna element. A hybrid beamforming beamforming architecture that combines both analog beamforming and digital beamforming may be able to generate multiple beams with a reduced TXRU, and in some examples, may inherit the problems of both analog beamforming schemes and digital beamforming schemes.

[0124] Some OFDM-based schemes (e.g., conventional OFDM-based schemes) may experience high peak-to-average power ratios (PAPRs) of transmitted signals, which may introduce performance degradation due to nonlinearities in power amplifiers. Techniques such as clipping may be used in these OFDM-based schemes and / or may cause some problems (e.g., one or more of the following: in-band distortion; out-of-band radiation; and / or destruction of orthogonality among subcarriers).

[0125] Figure 7 An example of a RIS-based transmitter (e.g., a RIS-based multi-user transmitter) is shown. RIS-based modulation may be used in one or more examples as described herein. RIS / RHS transmission may be implemented. As described herein, a transmitter may use RIS or RHS to perform transmission. The RIS may include, for example, a passive surface including a plurality (e.g., a large number) of elements (e.g., electronically programmable passive elements). A RIS controller may be used to control the RIS elements to adjust characteristics of a signal (e.g., a surge signal transmitted from an external source). As described herein, the RIS / RHS transmission may be implemented. As described herein, the RIS / RHS transmission may be implemented. Figure 7 As shown in the example RIS-based transmitter shown in the figure, the transmitter can be equipped with a single RF chain or multiple RF chains and a single antenna element or multiple antenna elements (e.g., Figure 3 N shown Tantenna elements). The RF chain may be used to provide a single-tone and unmodulated signal (e.g., providing a single-tone and unmodulated sine wave signal to a RIS-based transmitter). The transmitter may be equipped with a co-located controller that controls the RIS. In an example, the RIS may be deployed near the transmitter. The antenna may send the single-tone signal to the RIS, where the RIS controller configures the RIS elements to apply one or more of the following to the signal reflected toward multiple users: modulation, beamforming, or precoding (e.g., joint modulation, beamforming, and precoding). In an example, a base station (e.g., a gNB) may include one or more of the following (e.g., all): a baseband unit, a RIS controller, a RIS, or an antenna element associated with the RF chain.

[0126] Figure 8 An example of an RHS-based transmitter (e.g., an RHS-based multi-user transmitter) is shown. The RHS may include a plurality (e.g., a large number) of RHS elements (e.g., electronically programmable active elements). The RHS elements may generate beams and / or be controlled using an RHS controller. Figure 8 As shown in the example RHS-based transmitter shown, the transmitter may be equipped with a single RF chain or multiple RF chains connected to the RHS. The RF chain can be used to generate a single-tone and unmodulated signal (e.g., a sine wave), wherein the single-tone signal can be transmitted via the RHS (e.g., the RHS transmits the single-tone signal). The RHS controller can configure the RHS to apply one or more of the following to the signal reflected toward multiple users: modulation, beamforming, or precoding (e.g., joint modulation, beamforming, and precoding).

[0127] The RIS / RHS elements may be configured as described in one or more examples herein. The RIS / RHS elements may be used to reflect / transmit a signal x, where the reflection coefficient (denoted as φ) of the nth RIS element n ) can be based on the complex value x n For the xth RIS element, the reflection coefficient φ n The nth configurable load impedance is controlled and can be expressed as Equation 1, for example.

[0128]

[0129] In Equation 1, Z0 is the free space impedance, which is usually set to Z0 = 50Ω. n The corresponding amplitude β n and phase shift θ n For example, they can be written as Equation 2 and Equation 3, respectively.

[0130]

[0131] Fig. 9 The reflection coefficient (eg, the reflection coefficient φ n ) and configurable load impedance (e.g., configurable load impedance ), where Equation 4 and Equation 5 can be used to determine φ, respectively. n and

[0132]

[0133] A RIS / RHS-based transmission scheme may be described herein (e.g., a RIS / RHS-based transmission scheme with joint precoding, beamforming, and modulation). Precoding and beamforming may be performed digitally and employed in a non-digital manner (e.g., used in the analog domain, and, for example, a precoding matrix or a beamforming matrix may be used in the analog domain). For example, virtual digital processing may be implemented in this manner. In an example, for virtual digital processing, digital and analog processing (e.g., a mix of digital processing and analog processing) may be used. A plurality of example modulation schemes (e.g., PSK modulation, APSK modulation, and QAM modulation) may be presented or used in one or more examples herein.

[0134] RIS / RHS based joint precoding, beamforming and modulation may be described in one or more examples herein.A system model may be used in one or more examples as described herein. Fig.10 An example RIS / RHS-based transmission (eg, an example RIS / RHS-based multi-user transmission) is shown. Fig.10 As shown, a RIS / RHS wireless transmission system (eg, a basic RIS / RHS wireless transmission system) may be provided. The system may include one or more of the following parts (eg, formed using the one or more parts): a RIS / RHS wireless transmission system having n t A transmitter (Tx) with 1 antenna element (e.g. Figure 7 transmitter shown); RIS / RHS with n elements; K users (e.g., each user has N r antenna elements). In an example, the transmitter may be equipped with a RIS / RHS controller (e.g., a co-located RIS / RHS controller). The RIS / RHS controller may receive information from the baseband unit and configure (e.g., tune) the RIS / RHS elements (e.g., phase shift, amplitude, etc.) based on the input information (e.g., modulation, precoding, and beamforming information). Fig.10 As shown, the transmitter may be equipped with an RF chain 1006 (eg, with N t RF chain associated with a first antenna element of the N antenna elements) and / or RF chain 1008 (eg, associated with N tRF chain 1006 (or RF chain 1008) may be used to provide a single-tone (e.g., single carrier frequency) and unmodulated signal. In an example, RF chain 1006 may be a simplified RF chain that may not require up-conversion components. RF chain 1008 may be associated with the RHS (e.g., it may be used to generate a single-tone and unmodulated signal for the RHS).

[0135] Signal 1020 (eg, a single-tone and unmodulated signal, such as an impulse signal) may be (eg, from N t The RIS controller 1012 may configure the RIS / RHS elements of the RIS 1018 to apply one or more of the following to the signal 1020 (e.g., the input signal to the RIS 1018): modulation, beamforming, or precoding (e.g., joint modulation, beamforming, and precoding). The RIS controller 1012 may transmit the RIS / RHS elements of the RIS 1018 to the user 1016 (e.g., WTRU K) in conjunction with the RIS 1018 input signal. k 1014. A transmitter (e.g., a gNB) may include a baseband unit that generates a baseband signal 1010, which a RIS / RHS controller 1012 may use to configure RIS elements of a RIS 1018 and may include a RIS / RHS controller 1012. In an example, the transmitter may include a RIS 1018. In some examples, the RIS 1018 may be separate from the transmitter (e.g., the RIS 1018 may be deployed near the transmitter or away from the transmitter).

[0136] A transmit signal (e.g., including a transmit signal according to Equation 6) may be used in one or more examples as described herein. For example, to support multi-user transmission, the RIS / RHS may be adjusted in one or more examples as described herein to perform one or more of the following: modulation, beamforming, or precoding (e.g., joint modulation and / or beamforming / precoding). The transmit symbol X may include a precoding matrix P (e.g., a precoding matrix to implement multi-user transmission), a power allocation matrix Λ, and modulated information s. In an example, the transmit symbol may be determined using Equation 6.

[0137] x=ΛPs Equation 6

[0138] The channel model may be used in one or more examples as described herein. Fig.10 As shown, the channel between the transmitter and the kth user can be represented as (or expressed as) H k For example, the sender and K users (e.g., Fig.10The channel matrix between all users in the example shown can be represented by h = [H1, H2, ..., h K ] H ∈c K×N Given (for example, in the case of a single receive antenna at each user, such as N r =1). The channel fading between the RIS / RHS and the user may be represented by a channel model (e.g., a classical exponential correlation channel model may be used to represent the channel fading between the RIS / RHS and the user). For example, it may be assumed that the signal between the RIS and the user experiences Rayleigh fading (e.g., given the user mobility). The channel vector information may be determined based on one or more of the following: path loss from the RIS / RHS to the user, or small-scale fading from the RIS / RHS to the user. The channel vector information (e.g., channel vector ) can be used to determine (or given by), where ν r,k It can be used to represent the path loss from RIS / RHS to the kth user. Path loss ν r,k Available to determine (or be given by), where Can be used to express the path loss at a reference distance of 1 meter, α r can be used to represent the path loss exponent from RIS / RHS to the user, and d r,k can be used to represent the distance between RIS / RHS and the kth user. In the example, (For example, to determine the channel vector information ) can be used to represent the small-scale fading from a RIS (e.g., a RIS-based transmitter) to the kth user, where and R can be used to represent the channel vector The covariance matrix of . In the exponential correlation channel model, R can be determined based on the distance between adjacent RIS elements (e.g., determined by the distance d0 between adjacent RIS elements). In an example, the (n1, n2)th entry in R can be determined by Given, where can be used to represent the distance between the n1th RIS element and the n2th RIS element, and d ref A constant that can be used to represent the control correlation level. The path loss can be expressed as Υ = diag{v r,1 ,υ r,2 ,…,υ r,K}, and the small-scale fading from RIS / RHS to K users (e.g., all K users) can be expressed as W = [w1, w2, …, w K ] HThe channel matrix from RIS / RHS to K users (e.g., the equivalent channel matrix from RIS / RHS to all K users) can be obtained using to determine (or be given by).

[0139] One or more transmission components associated with a RIS-based precoding, beamforming, and modulation scheme may be used in one or more examples as described herein. The scheme may include transmission components (eg, precoding, beamforming, and modulation).

[0140] Digital-based analog precoding may be used in one or more examples as described herein. Multi-user precoding and modulation schemes (e.g., as described herein) may be based on digital processing and / or weights that may be applied in the analog domain (e.g., the weights may be applied in the analog domain using RIS / RHS elements). In an example, a controller (e.g., a RIS / RHS controller) may configure the RIS / RHS elements to apply precoding weights (e.g., the controller may (e.g., with the aid of an impedance unit) tune the RIS / RHS elements for applying the precoding weights after determining the weights of the multi-user precoding matrix P and the constellation symbols).

[0141] For example, the precoding matrix can be formulated as And / or the (N×1)-element pre-decoded symbol x can be expressed as Equation 7. The channel matrix H can be used to represent the full channel matrix obtained after CSI estimation (e.g., the extended channel information presented in one or more examples herein, e.g., ).

[0142] x=Ps Equation 7

[0143] For example, the controller may receive as an input signal (N×1) element pre-decoded symbols x. For example, the (N×1) element pre-decoded symbols x may be fed to the controller, which converts the symbols into an amplitude and phase configuration as shown in Equation 8.

[0144] x=[φ1 φ2…φ N Equation 8

[0145] In Equation 8, the nth coefficient of x can be obtained using to determine (or be given by). The RIS controller can use β n and θ n (For example, the amplitude β determined using Equation 2 and Equation 3, respectively n and phase shift θ n ) to tune the nth RIS / RHS element, such as Fig.11The information symbol s (e.g., the information symbol shown in Equation 7) may be based on PSK, APSK, QAM, and / or another modulation scheme (e.g., any other modulation scheme), wherein the transmitter may process the modulation scheme differently from another modulation scheme (e.g., each type of modulation may be processed differently in a RIS / RHS based transmitter). Fig.11 An example RIS / RHS controller is shown (eg, a RIS / RHS controller that uses phase and amplitude information of x to tune RIS / RHS elements).

[0146] One or more of RIS-based joint precoding, beamforming, and PSK / A-PSK modulation may be used in one or more examples as described herein. In an example, a transmitter (e.g., a RIS / RHS-based transmitter) may be configured to transmit modulated information (e.g., PSK / QAM modulated information for K users), wherein a total number of ports allocated for transmitting modulated information to the users may be determined (e.g., as discussed in one or more examples herein). Information may be modulated in phase and / or amplitude dimensions (e.g., or I / Q) prior to MU precoding.

[0147] For example, after obtaining the symbols of K users (for example, s1, s2, ..., s K After receiving the symbols of the K-th user, the transmitter (e.g., a RIS / RHS-based transmitter) may obtain the precoding weights of the K-th user (e.g., all the K-th user), which may be represented or expressed as P1, ..., P K The transmitter may construct the pre-decoded symbol x, for example, using Equation 9. A baseband processor (eg, a baseband unit for generating the digital baseband signal 1010) may feed a baseband signal (eg, the pre-decoded symbol x determined using or given by Equation 9) to the RIS / RHS controller.

[0148]

[0149] In Equation 9, s k It can be used to represent the M-ary PSK / QAM information symbol of the k-th user, Given (for example, or in the case of PSK modulation ), p k can be used to represent the pre-decoding vector of the kth user (for example, where ), and λ k may be used to represent the power allocated to the kth user of the RIS / RHS. For example, the precoded symbol x may be reflected and / or transmitted from N RIS / RHS elements (eg, all N RIS / RHS elements).

[0150] The power sent from an element (e.g., each element) may be And the reflected / transmitted effective power can be The total power reflected / transmitted from N elements (eg, all N elements) (denoted as E r ) can be determined using (or given by) Equation 10.

[0151]

[0152] In equation 10, It can be used to represent the average power reflectivity / transmittance of RIS / RHS components. n ≤1, so the power reflectivity / transmittance can satisfy 0≤ξ≤1, and / or Equation 11 can be used.

[0153] λ1+λ2+…+λ K =E r =E s ξ Equation 11

[0154] Equation 11 can be normalized as shown in Equation 12.

[0155] λ′1+λ′2+…+λ′ K =1 Equation 12

[0156] The baseband signal x (e.g. Fig.10 The baseband signal 1010 in can be determined (or described) using Equation 13.

[0157]

[0158] In this case, the modulated symbol s k and p k The pre-decoded information in may be integrated into x (eg, baseband signal x determined using Equation 13), where x may be reflected / transmitted by the RIS / RHS by tuning the N RIS / RHS elements as shown in Equation 14.

[0159] x=[φ1 φ2…φ N Equation 14

[0160] The pre-coded symbols may be obtained digitally (e.g., as described in one or more examples herein) and then applied non-digitally to the RIS / RHS elements (e.g., as described in one or more examples herein). Fig.11The modulation and precoding scheme (e.g., any modulation and precoding scheme) may be applied as shown in the figure. For example, a modulation (e.g., any modulation) with an amplitude component (e.g., APSK, QAM, etc.) may not result in PAPR because the amplitude component may be obtained as a mixed result of RIS / RHS element power control (e.g., a modulation with an amplitude component may not result in any PAPR because the amplitude component of the transmitted signal may be transmitted not through a power amplifier but through a beamforming gain).

[0161] Features associated with a single user with QAM modulation may be provided. In an example, a RIS / RHS based transmitter having N elements may be transmitting QAM based symbols to a single receiver (e.g., a single receiver having a single antenna element). For example, the transmit signal may be a single tone signal. The single tone signal (e.g., transmitted from a feed antenna or transmitted from an RHS in the case of a RIS) may be a single tone signal having a center frequency of f c For example, the transmit signal may be determined using (or given by) Equation 15.

[0162] g = cos(2πf c ) Equation 15

[0163] For a given QAM symbol, the RIS / RHS element may be configured by a controller (e.g., a RIS / RHS controller) to transmit the symbol This can be done by setting the phase shift of the elements (e.g., all elements) to θ i And set their amplitudes to β l to achieve this, as shown in Equation 16.

[0164]

[0165] In Equation 16, the aggregate magnitude can be expressed using ∑β n =Aa l , where A is the scaling factor of the N RIS / RHS elements. For example, the reflected / transmitted signal may be determined using (or given by) Equation 17.

[0166]

[0167] The signal received at the user can be determined using (or given by) Equation 18.

[0168] y=hx+n Equation 18

[0169] In Equation 18, x may be determined (or expressed) as shown in Equation 19 and / or Equation 20.

[0170] y=(Aa lcosθ i cos 2πf c t-Aa l sinθ i sin2πf c t)+n Equation 19

[0171] x=Icos 2πf c t-Qsin2πf c t+n Equation 20

[0172] Multi-carrier transmission may be provided. A single user with a QAM modulation transmission scheme described herein may be extended to multi-carrier transmission. In an example, a transmitter (e.g., a transmitter as described in one or more examples herein) may be configured to transmit a single user with a QAM modulation scheme described herein to multiple carriers. fft OFDM modulation is applied on the subcarriers and / or a fixed cyclic prefix (CP) is added to send CP-OFDM symbols. This operation can be performed digitally, for example, before feeding the OFDM pre-coded symbols (e.g., CP-OFDM) to the RIS / RHS controller.

[0173] Fig.12 An example block diagram of CP-OFDM is shown. In the example, at a given transmitted symbol The period T = N fft T s In the case of, for example, the OFDM symbol can be determined (or expressed) as shown in Equation 21.

[0174]

[0175] In Equation 21, given that For the nth fft The pre-decoded symbols sent at subcarriers, Convert to

[0176] For example, the pre-decoded OFDM symbol r(t) can then be fed into the fft (For example, for each n fft ) as control information in the RIS / RHS controller, as shown in Equation 22.

[0177]

[0178] RIS / RHS can then be based on the N coefficients Configuration (for example, N coefficients The OFDM symbol is reflected / transmitted by the configuration of each coefficient in .

[0179] In some OFDM schemes (e.g., conventional OFDM schemes), a transmitted signal may experience PAPR issues as it passes through a nonlinear power amplifier, which may introduce performance degradation. In one or more examples as described herein (e.g., in the case of using a RIS / RHS-based transmitter), the resulting OFDM signal may not have a significant PAPR (e.g., may not experience any PAPR because large peaks may be transmitted using the aggregate RIS / RHS element power). For example, a RIS / RHS-based signal (e.g., a RIS / RHS-based transmission in one or more examples as described herein) may not experience distortion and / or out-of-band radiation (e.g., any distortion and out-of-band radiation).

[0180] Power allocation can be performed in one or more examples herein. A RIS / RHS-based power allocation technique can be provided. The power of the signal reflected / transmitted on the RIS / RHS can be divided among users (e.g., to obtain maximum performance in terms of sum rate, minimum rate, etc.).

[0181] For example, the kth user may receive the following signal, as shown in a series of equations represented by Equation 23.

[0182]

[0183] In Equation 23, (a) and (b) can be obtained respectively, because when k≠l, And when k = l,

[0184] The received signal to interference plus noise ratio (SINR) of the kth user may be determined using (or given by) Equation 24.

[0185]

[0186] The achievable rate for the kth user can be determined (or expressed) using Equation 25.

[0187]

[0188] Power sharing ratio λ′1+λ′2+…+λ′ K and / or the corresponding power reflectivity ξ may be determined, for example using an optimization technique, under one or more of the following: λ′1+λ′2+…+λ′ K =1 and / or constraints.

[0189] In an example, an alternating optimization (AO) technique may be used to calculate (e.g., iteratively calculate) a power sharing ratio and a power reflectivity, for example, while simultaneously relying on one or more of the techniques described herein: a maximized sum rate method, a maximized minimum rate method, and / or a maximized geometric mean rate technique.

[0190] A maximization and rate technique may be described herein. In the maximization and rate technique, a total spectral efficiency of a receiver (e.g., all receivers) may be maximized. In this technique, when the average SNR of a user (e.g., all users) is in a low SNR region, the reflected signal power may be primarily allocated to a receiver with relatively good conditions. When the average SNR of a receiver (e.g., all receivers) is in a high SNR region, power is approximately uniformly (e.g., uniformly) allocated to the user (e.g., all users). Applying the maximization and rate technique may maximize the throughput of the entire system.

[0191] Based on the achievable rate C k The sum rate of the K users can be determined using (or given by) Equation 26.

[0192]

[0193] Then, for example, maximizing R sum The optimization problem of can be formulated as shown in Equation 27.

[0194]

[0195] First, if the power reflectivity ξ is fixed and the second constraint in (P1.a) is ignored, the optimization procedure (P1.a) can be written as Equation 28, for example.

[0196]

[0197] The optimization procedure (P1.b) can then be solved, for example, by classical water injection techniques.

[0198] Secondly, the power sharing ratios λ′1,λ′2,…λ′ can be obtained K , then, for example, a bisection method can be used to find the power reflectivity ξ that satisfies the second constraint in (P1.a).

[0199] The process of the alternating optimization technique for maximizing and rate can be presented in Example 1 (eg, Example Algorithm 1), where ξ min is the lower limit of ξ, and the initial ξ min Can be set to 0, ξ max is the upper limit of ξ, and the initial ξ max Can be set to 1. ε ξcan be the maximum allowable error of ξ, and given ξ,υ r,1 ,υ r,2 ,…,υ r,K In the case of It can be a function of calculating, for example, the power sharing ratio of each user by using classical water filling techniques.

[0200] A maximizing minimum rate technique may be described herein. In the maximizing minimum rate technique, the minimum rate of the receiver may be maximized. Here, power may be allocated to ensure that users (e.g., all users) have the same received SNR. In some examples, although maximizing the sum rate may achieve a high throughput (e.g., the highest possible throughput) for the entire system, this may be unfair to users with poor channel conditions. This may be because, for example, most of the power is allocated to users with good channel conditions. This may leave a rate of, for example, close to zero for users with low SNR. A maximizing minimum rate-based power sharing technique (e.g., by contrast) may maximize the minimum rate of users (e.g., all users). Based on the achievable rate C k The formula for K users (for example, all K users, denoted as R min ) can be determined using (or given by) Equation 29.

[0201]

[0202] For example, maximizing R min The problem can be formulated as Equation 30.

[0203]

[0204] First, the power reflectivity ξ can be fixed and the second constraint in (P2.a) can be ignored. Then, the optimization procedure (P2.a) can be written as Equation 31, for example.

[0205]

[0206] The optimization problem (P2.b) may include or be equivalent to, for example, ensuring that the spectral efficiency of the K users (eg, all K users) is the same. Thus, for example, Equation 32 is obtained.

[0207] υ r,1 λ′1=υ r,2 λ′2=…υ r,K λ′ K Equation 32

[0208] Since λ′1+λ′2+…+λ′ k=1, so the power sharing ratio of (eg, each) user can be determined using (or given by) equation 33.

[0209]

[0210] Then, λ′ k Can be obtained by r,1 ,υ r,2 ,…,υ r,K to determine (eg, completely determine).

[0211] Second, the power sharing ratio λ′1 λ′2 … λ′ K can be fixed (e.g., similar to maximizing the sum rate), and a bisection technique can be used to find the maximum value of the power reflectivity that satisfies the second constraint ξ in (P2.a). The detailed process of the alternating optimization technique for maximizing the minimum rate can be shown in Example 1 (e.g., Example Algorithm 1), where [λ′1λ′2 … λ′ K ]=f(υ r,1 ,υ r,2 ,…,υ r,K ) mim An example function for calculating the power sharing ratio of a user (e.g., given υ r,1 ,υ r,2 ,…,υ r,K In the case of , the power sharing ratio function of each user is calculated by maximizing the minimum rate).

[0212] A maximized geometry rate technique may be provided. The maximized geometry rate technique may be a trade-off between a maximized sum rate technique and a maximized minimum rate technique. In low SNR regions, the maximized geometry rate technique may often become similar to (e.g., equivalent to) the maximized minimum rate technique, and power may be primarily allocated to users with poorer channel conditions (e.g., to ensure fairness to users (e.g., all users)).

[0213] Different from the power allocation techniques in some MIMO (eg, conventional MIMO) systems, the power allocation ratios λ′1,λ′2,…,λ′ K can be designed with the constraint that the amplitude of the baseband signal is not greater than 1, since the passive nature of the RIS element does not add (e.g., any) power / amplitude gain (e.g., in the case of using RHS, a power constraint equal to 1 can be applied to fix the maximum transmit power to P t =1). In an example, the conceptual power reflectivity ξ can be used to satisfy this constraint.

[0214] For example, the maximization geometric mean rate technique may be used because it shows improved rate fairness among users. k The geometric mean of the achievable rates of K users (e.g., all K users) (denoted as R GM ) can be expressed as Equation 34, for example.

[0215]

[0216] For example, maximizing R GM The problem can be formulated as Equation 35.

[0217]

[0218] First, if the power reflectivity ξ can be fixed and the second constraint in (P3.a) can be ignored, the optimization problem (P3.a) can be written as Equation 36, for example.

[0219]

[0220] For example, Equation 36 can be solved by using the classical Lagrange multiplier technique in the calculus of variations.

[0221] Afterwards, an alternating optimization technique (eg, a classical alternating optimization technique) may be used to find the optimal power sharing ratio λ′1λ′2…λ′ K and the corresponding power reflectivity ξ to maximize the geometric mean rate.

[0222] Example 1 may be an example of an alternating optimization technique for a maximize-and-rate / minimum-rate / geometric-mean-rate power allocation scheme.

[0223] Example 1 (eg, Example Algorithm 1)

[0224]

[0225] The port allocation can be adaptive. Adaptive port allocation can be performed in one or more examples herein (eg, using methods and processes associated with adaptive port allocation).

[0226] The WTRU may notify a base station (e.g., a gNB) of virtual channel characteristics (e.g., channel characteristics determined using an extended channel matrix as described in one or more examples herein) associated with a port (e.g., a virtual antenna port). RIS-based transmissions may use or rely on RIS / RHS for transmission, as described in one or more examples herein. The base station may dynamically allocate virtual antenna ports available through RIS. In one or more examples herein, the WTRU may, for example (e.g., based on channel measurements), notify the base station of virtual channel characteristics of an array (e.g., a full array) of virtual antenna ports so that the base station may dynamically allocate virtual antenna ports available through RIS.

[0227] The WTRU may inform the base station of the virtual channel characteristics of the full array of virtual antenna ports (e.g., ports determined using an extended channel matrix as described in one or more examples herein), for example, by transmitting a virtual CSI report. A virtual CSI report (e.g., a CSI report generated using an extended channel matrix as described in one or more examples herein) may be generated and / or transmitted to, for example, a base station.

[0228] The number of ports may be limited by the number of radio chains available at the transmitter. An antenna port may be associated with a logical antenna (e.g., the antenna port may not refer to a physical port). In an example, the maximum number of ports may be limited by the number of radio chains available at the transmitter (e.g., 16 to 32). Logical antennas (e.g., associated with virtual antenna ports) may be suitable for RIS-based transmission, where the transmission is implemented with the aid of a RIS / RHS controller. In some examples, the number of streams transmitted may not be related to the number of radio chains. For example, the number of ports may be determined based on uncorrelated channels between the transmitter and K users (e.g., the number of ports (e.g., virtual antenna ports) may be equivalent to the maximum number of uncorrelated channels between the transmitter and K users), because the number of streams transmitted may not be related to the number of radio chains. For example, given a number of K users, the total number of antenna ports of a RIS-based transmitter may be equivalent to the total number of uncorrelated channels for the number of K users (e.g., all users). Where L k The total number of uncorrelated channels for each user (e.g., the number of layers; the uncorrelated channels can be associated with or correspond to layers). One or more users (e.g., all users) can be assigned in the same resources (e.g., time resources and frequency resources), where the number of users can change (e.g., K>32), and / or the number of ports (e.g., virtual antenna ports) for each user can change. In this way, one or more examples herein can provide, for example, using dynamic resource allocation based on virtual CSI reporting.

[0229] The number of uncorrelated channels may be determined based on channels associated with the RIS / RHS (e.g., based on channel measurements). For example, to determine the number of uncorrelated channels between the WTRU and a base station (e.g., a gNB), the WTRU may determine the channel between the RIS / RHS and a receive antenna (e.g., a receive antenna of the WTRU). The WTRU may perform channel measurements on CSI-RS resources (e.g., the CSI-RS resources may be mapped to RIS elements). The CSI-RS resources may or may not be directly mapped to physical antennas. In some examples, the channel measured at the WTRU may not represent the actual physical channel.

[0230] The base station may configure some CSI-RS resources (e.g., CSI-RS ports) for the WTRU. The CSI-RS resources may be associated with RIS elements (e.g., CSI-RS ports associated with RIS elements). The WTRU may receive CSI-RS on the CSI-resources via the RIS (e.g., RIS elements associated with the CSI-RS resources). The WTRU may receive CSI-RS from a transmitter (e.g., a transmitter in one or more examples as described herein, e.g., Fig.10 The transmitter (shown in FIG. 1 ) receives the CSI-RS. The transmitter may be associated with a RIS (eg, the transmitter may include a RIS controller that configures the RIS).

[0231] The WTRU may perform measurements based on one or more CSI-RS (e.g., based on a CSI-RS received via a RIS). The WTRU may not receive a corresponding CSI-RS for each element of the RIS. The WTRU may receive a CSI-RS associated with a first element of the RIS (e.g., an active element) or a first subset of elements of the RIS, and may not receive a CSI-RS associated with a second element of the RIS (e.g., a non-active element) or a second subset of elements of the RIS. The WTRU may not perform measurements associated with an element of the RIS (e.g., a non-active element) (or a subset of elements of the RIS) that has not received a CSI-RS associated with an element of the RIS (or a subset of elements of the RIS). For example, the measurements performed by the WTRU may be limited to a first element of the RIS (e.g., a non-active element) or a second subset of elements of the RIS. Fig.24 Active element 2406 shown) or a first subset of elements of the RIS (e.g., Fig.24 The active element shown includes active element 2406), wherein the first element or the first subset has received the CSI-RS.

[0232] For example, the WTRU may determine a virtual channel based on measurements (e.g., the WTRU may use interpolation to estimate the virtual channel). The virtual channel may include channel information (e.g., channel vector information) associated with an element (or a subset of elements) that has not received a CSI-RS associated with the element (or a subset of elements). For example, the WTRU may use interpolation to estimate channel information associated with an element (or a subset of elements of a RIS) that has not received a CSI-RS.

[0233] In some examples, the WTRU may perform additional measurements on the received CSI-RS to determine a virtual channel and / or obtain a virtual CSI report. A virtual channel may include (or in some examples may be defined as) channel information of a CSI report after post-processing (e.g., up-conversion) that reflects the channel characteristics of the entire array of extended portions or virtual antenna ports.

[0234] The WTRU may receive information (e.g., configuration information) associated with the RIS / RHS. For example, the information may indicate a configuration associated with one or more elements of the RIS. For example, the information (e.g., information to be exchanged between a RIS / RHS-assisted transmitter and the WTRU) may include one or more of the following: RIS / RHS size (e.g., number of elements); number of horizontal RIS / RHS elements and / or vertical RIS / RHS elements; RIS / RHS element configuration (e.g., phase, amplitude, polarization, etc.). The information may, for example, indicate a configuration associated with a first subset of elements of the RIS and a configuration associated with a second subset of elements of the RIS.

[0235] The information associated with the RIS / RHS may include block partitioning information associated with the RIS. The block partitioning information associated with the RIS may indicate that the RIS includes one or more blocks of elements. For example, a base station (e.g., a gNB) may partition the RIS / RHS into blocks and / or sub-blocks (e.g., such as Fig.24 as shown), for example to determine a RIS / RHS assisted transmitter. Fig.24 An example of dividing the RIS / RHS array into blocks for CSI-RS transmission is shown. Fig.24As shown, the RIS / RHS array may be divided into 4 blocks (e.g., including block 2402 and block 2404), where each block includes 16 RIS elements. A base station and / or a transmitter (e.g., a RIS / RHS-based transmitter, e.g., a RIS / RHS-assisted transmitter) may configure one or more CSI-RS resources based on blocks (e.g., such that each block or set of blocks in a block may be dedicated to a CSI-RS port). For example, block 2402 may be associated with a first CSI-RS. Block 2404 may be associated with a second CSI-RS. Blocks 2402 and 2404 may be associated with a first CSI-RS or a second CSI-RS. In some examples, elements of a block may be associated with a CSI-RS.

[0236] The base station and / or the transmitter (e.g., a RIS / RHS based transmitter, e.g., a RIS / RHS assisted transmitter) may activate one or more elements per block to transmit the CSI-RS. Fig.24 As shown, gray squares may be used to represent active elements (e.g., activated elements), and white squares may be used to represent inactive elements (e.g., elements that have not been activated, e.g., deactivated elements). Element 2408 of block 2404 may be an inactive element, and element 2406 of block 2404 may be an active element. For example, element 2408 may not be associated with a CSI-RS, and element 2406 may be associated with a CSI-RS. The activation of one or more elements associated with a RIS may be random or follow certain rules / patterns.

[0237] The information associated with the RIS / RHS may indicate activation of the elements associated with the RIS / RHS. For example, the information associated with the RIS may indicate that element 2408 of block 2402 is an inactive element and element 2406 of block 2404 is an active element.

[0238] For example, information associated with the RIS / RHS (e.g., regarding block partitioning and / or element activation) may be signaled to the WTRU. In an example, the information may be listed in a predefined lookup table and / or the table index may be signaled to the WTRU (e.g., via DCI or MAC). In some examples, the information associated with the RIS / RHS may be signaled to the WTRU (e.g., MAC-CE).

[0239] For example, after receiving the CSI-RS at the WTRU, the WTRU may perform channel estimation to obtain CSI reporting parameters (e.g., one or more of the following: channel quality indication (CQI), precoding matrix indicator (PMI), rank indicator (RI), or layer indicator (LI)). For example, the WTRU may perform measurements based on the received CSI-RS. For example, the measurements performed by the WTRU may be limited to the first element of the RIS (e.g., Fig.24 Active element 2406 shown) or a first subset of elements of the RIS (e.g., Fig.24 The WTRU may determine CSI reporting parameters (eg, CSI reporting parameters as opposed to virtual CSI reporting parameters) based on the measurements.

[0240] For example, the WTRU may determine the channel matrix after receiving the CSI-RS at the WTRU. The WTRU may determine the first channel matrix based on measurements performed based on the received CSI-RS. In an example, the WTRU may determine channel information (e.g., channel vector information) for one or more active RIS / RHS elements of the RIS / RHS and / or determine the first channel matrix based on the determined channel information for the one or more active RIS / RHS elements. For example, the WTRU may determine the channel matrix H i , where H i Can be used to represent N a active RIS / RHS components and the WTRU's N r For example, the channel matrix H i To obtain the extended channel matrix Using the channel matrix H i To determine the virtual CSI report.

[0241] The WTRU may determine a second channel matrix (e.g., an extended channel matrix) based on a first channel matrix determined based on channel measurements (e.g., channel measurements performed using a received CSI-RS). For example, the WTRU may use the channel matrix H i For example, by using up-conversion techniques (e.g., interpolation) to construct an extended channel matrix, the constructed extended channel matrix may include channel information (e.g., channel vector information) of one or more non-active RIS / RHS elements. Equation 37 is an example channel matrix H i , which may be used by the WTRU when a single element is activated per block of the RIS / RHS. As shown in Equation 37, the channel matrix H i Can include multiple channel matrix coefficients The channel matrix coefficients (e.g., ) may be associated with an element of the RIS / RHS (eg, an active element) and / or may indicate channel information associated with the element (eg, channel vector information).

[0242]

[0243] The determination of the second channel matrix may also be based on information associated with the RIS / RHS. For example, the configuration information associated with the RIS may indicate a configuration associated with the first subset of elements of the RIS and / or a configuration associated with the second subset of elements of the RIS, such as Fig.24 For example, the WTRU may use knowledge associated with the RIS (e.g., knowledge of the block partitioning and / or the total number of elements per block) to post-process the channel (e.g., using interpolation) to determine the extended channel matrix Extended Channel Matrix Can be used to represent up to N t Send RIS / RHS elements (e.g., N t Can be greater than N a ) and N r elements (e.g., N of a WTRU r In an example, the WTRU may use information received from a base station (e.g., gNB) regarding block partitioning and / or element activation (e.g., information associated with RIS / RHS) to extend the channel matrix H i Map to another matrix Where the positions of the inactive elements may be set to zero, as shown in example Equation 38.

[0244]

[0245] The mapping of zero coefficients and non-zero coefficients (eg, as shown in Equation 38) may be used (eg, for interpolation) to determine the extended channel matrix In addition to the channel matrix coefficients In addition, the extended channel matrix may also include one or more channel matrix coefficients. The channel matrix coefficients in the additional channel matrix coefficients may be associated with elements (e.g., non-active elements) of the RIS / RHS. The extended channel matrix (e.g., the post-processed extended channel matrix) Can be used for multi-user (MU) transmission in one or more examples herein.

[0246] The WTRU may determine CSI reporting parameters based on channel information of one or more non-active RIS / RHS elements and / or channel information of one or more active RIS / RHS elements. For example, using extended channel information (e.g., with an extended channel matrix The WTRU may determine (e.g., calculate) one or more virtual CSI reporting parameters (e.g., one or more of the following: CQI (V-CQI), V-PMI, V-RI, or V-LI), for example, based on the report type (e.g., type I and type II as shown in Table 1). The WTRU may transmit one or more virtual CSI reporting parameters based on the report type (e.g., CSI reporting parameters determined using an extended matrix as described in one or more examples herein). In an example, the WTRU may be based on a block of elements of the RIS / RHS (e.g., Fig.24 2404) to determine CSI reporting parameters, and the CSI reporting parameters may be associated with a block of the element (e.g., the CSI reporting parameters may not be associated with other blocks of the element of the RIS / RHS, such as Fig.24 Block 2402 shown).

[0247] The WTRU may report a CSI report and / or a V-CSI report, for example, Fig.25 shown. Fig.25 An example of determining and reporting a CSI report and / or a V-CSI report is shown. Fig.25 As shown, at 2504, a transmitter (e.g., a RIS-based gNB / TRP) may configure and / or transmit a CSI-RS to a WTRU. The WTRU may perform one or more of the following: determine CSI measurements using the CSI-RS; upconvert; determine a virtual channel; determine a virtual channel report (e.g., a virtual CSI report as described in one or more examples herein). At 2506, the WTRU may transmit a report completion acknowledgment (ACK) to the transmitter (e.g., a virtual CSI report completion ACK). At 2508, the transmitter may transmit a request for a CSI report and / or a V-CSI report to the WTRU. At 2510, the WTRU may transmit a CSI report and / or a V-CSI report to the transmitter.

[0248] Table 1. Examples of CSI report content and V-CSI report content

[0249] CSI Report Content Virtual CSI Report Contents type CRI, RI, PMI, CQI V-CRI, V-RI, V-PMI, V-CQI Type I / II CRI, RI, PMI, CQI, LI V-CRI, V-RI, V-PMI, V-CQI, V-LI Type I / II CRI, RI, LI V-CRI, V-RI, V-LI Type I CRI, RI, CQI, LI V-CRI, V-RI, V-CQI, V-LI Type I

[0250] Port reporting (e.g., port reporting associated with CSI) may be performed dynamically (e.g., as shown in dynamic port reporting in one or more examples herein). In an example, the WTRU may be configured for RIS-based transmission (e.g., by RRC or MAC). The configuration may include one or more of the following: a maximum number of CSI-RS and / or demodulation reference signal (DMRS) ports that can be supported; antenna port resources (e.g., in the time domain and the frequency domain), wherein the maximum number of CSI-RS ports and DMRS ports may be modified. The configuration may include a RIS-based transmission configuration. The RIS-based transmission configuration may include antenna port resources (e.g., time and frequency resources for antenna ports, including one or more of a start symbol, a frequency domain RE position, etc.). The antenna port resources may be based on a predefined table. For example, the antenna port resources may be defined in an RRC message. For example, the antenna port resources may be modified by an RRC message. In an example, the antenna port resources in the time domain and / or the frequency domain may be configured and / or signaled based on a predefined table, configured in an RRC message, and / or modified by an RRC message.

[0251] In an example, information associated with RIS / RHS may include configuration information for RIS-based transmission. Configuration information for RIS-based transmission may include information about block partitioning and / or element activation. Configuration information for RIS-based transmission may indicate one or more of the following: the number of supported ports (e.g., the maximum number of supported CSI-RS antenna ports and / or DM-RS antenna ports). In some examples, the number of supported ports may be modified. Configuration information for RIS-based transmission may indicate antenna port resources in the time domain and / or frequency domain (e.g., starting symbol, frequency domain RE position, etc.). Configuration information for RIS-based transmission may be transmitted and / or received via a radio resource control (RRC) message and / or modified via a MAC.

[0252] For example, adaptive port allocation may be performed at a RIS-based transmitter (e.g., a RIS-based transmitter as described in one or more examples herein, e.g., a RIS-assisted transmitter). For example, a base station (e.g., a gNB) may use one or more reports (e.g., CSI reports and / or V-CSI reports) to dynamically allocate ports (e.g., transmit ports) to users (e.g., each user) after receiving CSI reports and / or V-CSI reports associated with K users. In an example, one or more of the following may be performed, for example, by a base station. The base station may include a gNB or a transmit / receive point (TRP), e.g., a RIS-based gNB or TRP. The base station may request the user to communicate using RIS-based transmission. The base station may receive CSI reports and / or virtual CSI reports from K users. The base station may group one or more of the K users into a transmit group (e.g., a specific MU transmit group G). The base station may determine the number of ports (e.g., the total number of ports) based on the CSI report and / or V-CSI report of each user. For example, for some CSI and / or V-CSI reports from a user, the V-RI may be greater than the RI (e.g., a conventional RI, e.g., V-RI>RI), which may allow more ports to be allocated to the user. The base station may perform dynamic port allocation for each user in a (e.g., each) group. For example, the base station may signal port resource information to the users in the group. In an example, the WTRU may receive a request to communicate using RIS-based transmissions. For example, after the WTRU transmits CSI reporting parameters to the base station, the WTRU may receive an indication of one or more ports (e.g., a transmit port). The CSI reporting parameters may be included in the CSI report and / or the V-CSI report. The WTRU may decode the RIS-based transmission based on the indication of the one or more ports.

[0253] Fig.26An example of a port allocation for associated with RIS-based transmission is shown. At 2604, a base station (e.g., a gNB) may determine and / or indicate that the base station is capable of RIS-based transmission. At 2606, a WTRU may be configured for RIS-based transmission. For example, the WTRU may receive configuration information for RIS-based transmission. The configuration information may indicate a CSI-RS associated with an antenna port associated with the RIS. At 2608, the WTRU may perform channel measurements (e.g., including channel measurements using CSI-RS) using one or more CSI-RS. At 2610, the WTRU may determine a virtual channel, for example, using up-conversion (e.g., interpolation). For example, the WTRU may determine a virtual channel characteristic associated with a full array of virtual antenna ports based on one or more channel measurements in the channel measurement. The WTRU may determine (e.g., calculate) a virtual CSI report (e.g., a virtual CSI report indicating a virtual channel characteristic). At 2612, the WTRU may transmit a CSI report and / or a virtual CSI report. For example, the WTRU may transmit a first CSI report and / or a second CSI report (e.g., a legacy CSI report) including virtual channel characteristics (e.g., number of radio communication layers for the WTRU, PMI, LI, etc.). At 2614, the base station may assign one or more WTRUs to different groups (e.g., different transmit groups) and / or determine a number of ports (e.g., a total number of virtual ports). At 2616, the base station may perform joint precoding and / or modulation (e.g., as described in one or more examples herein). For example, the base station may determine joint precoding and / or modulation for the WTRUs (e.g., each WTRU in a group of WTRUs and / or each WTRU in each group of WTRUs). A controller associated with the RIS (e.g., a RIS (or RHS) controller) may receive precoded modulated symbols, for example, from a baseband unit. The controller associated with the RIS may apply the precoded modulated symbols to the RIS elements (e.g., each RIS element).

[0254] In an example, the base station may perform port allocation (e.g., dynamic port allocation) for each WTRU in the group. The WTRU may, for example, receive an indication of one or more ports (e.g., virtual antenna ports) and / or receive a request to communicate using RIS-based transmissions from the base station. The WTRU may decode the RIS-based transmissions based on the request and / or the indication of the one or more ports.

[0255] Simulation results are provided. The simulation results highlight the capabilities of the MU transmission scheme described in this paper.

[0256] Fig.13An example of theoretical and simulation comparison of spectral efficiency versus transmit power for MIMO in a LoS channel (eg, conventional MIMO) and a RIS-based single RF downlink information transfer system in a Rayleigh channel is shown. Fig.14 An example of theoretical and simulation comparison of symbol error probability versus transmit power Es for a MIMO in a LoS channel (e.g., conventional MIMO) and a RIS-based single RF downlink information transfer system in a Rayleigh channel is shown. Fig.13 and Fig.14 As shown, a comparison between the spectral efficiency and symbol error probability of a RIS / RHS based transmitter and some MIMO schemes (e.g., conventional MIMO schemes) can be provided. Here, the RIS / RHS based transmission can be associated with a single RF chain for providing a RIS (e.g., or RHS) single frequency tone signal. Fig.13 and Fig.14 It is observed in Figure 1 that the performance of the RIS / RHS based transmitter scheme improves based on increasing the number of RIS elements. It can be seen that when the number of RIS elements is doubled, the transmitter obtains about 3dB of channel gain. This may be similar to some MIMO systems (e.g., conventional MIMO systems), where doubling the number of RF chains results in a 3dB channel gain. When N=2048 RIS elements are deployed, the RIS / RHS based transmitter can successfully outperform N in the LoS channel. RF = Some MIMO systems (eg, conventional MIMO systems) are associated with 64 RF chains. In an example, a single RF chain (eg, only a single RF chain) may be required in a RIS / RHS based transmitter.

[0257] Fig.15 The number of RF chains (N) in some MIMO systems (eg, conventional MIMO systems) is shown. RF ) and the number of RIS elements (N) in a RIS-assisted single RF information transfer scheme when achieving the same traversal rate. Fig.15 As shown, the number of RF chains (N) in some MIMO systems (eg, conventional MIMO systems) is RF ) and the number of RIS elements (N) in a RIS / RHS based transmitter when the same traversal rate can be achieved. Fig.15 As can be seen from the figure, for a given number of users, a single RF chain may require more RIS / RHS elements than a system with a large number of RF chains (e.g., a conventional MIMO system). For example, a RIS / RHS-based transmitter with N=4000 RIS elements may outperform a transmitter with N=4000 RIS elements when supporting K=32 users. RF = A MIMO system with 40 RF chains (eg, a conventional MIMO system).

[0258] Fig.16 shows (for example, when considering different power allocation techniques) and the rate R sum , minimum rate R min , geometric mean rate R GM Example of simulation comparison with the average received SINRρ. Fig.16 As shown, represented by R sum The sum rate, denoted as R min The minimum rate, denoted as R GM The simulation results of the geometric mean rate can be compared with the average received SINRρ when considering three power allocation techniques. Among the three power allocation techniques, the maximum sum rate technique can achieve the highest sum rate, while the maximum minimum rate technique can achieve the highest minimum rate, and the maximum geometric mean rate technique can achieve the highest geometric mean rate, which is in line with the original intention of (e.g., each) power allocation technique. In the maximum sum rate technique, at the low reception SINR area, more power can be allocated to users with good channel conditions, while at the high reception SINR area, power can be (e.g.) approximately uniformly allocated to users (e.g., all users). In the maximum minimum rate technique, more power can be allocated to users with poor conditions. The maximum geometric mean rate technique can be a trade-off between the maximum sum rate technique and the maximum minimum rate technique. This can indicate that at the low SINR area, the maximum geometric mean rate technique may often become similar to (e.g., equivalent to) the maximum minimum rate technique that allocates more power to users with poor conditions, while at the high SINR area, the maximum geometric mean rate technique tends to be the maximum sum rate technique that allocates power uniformly to users (e.g., all users).

[0259] Fig.17 The sum rate R is shown for different channel correlation values ​​(eg, when the sum rate is calculated using the maximization sum rate technique, the minimum rate is calculated using the maximization minimum rate technique, and the geometric mean rate is calculated using the maximization geometric mean rate technique). sum , minimum rate R min , geometric mean rate R GM Example of simulation comparison with the average received SINRρ. Fig.17 As shown, for different channel correlation values, the sum rate R sum , minimum rate R min and the geometric mean rate R GMCompared with the average received SINRρ, the sum rate is calculated using the maximization sum rate technique, the minimum rate is calculated using the maximization minimum rate technique, and the geometric mean rate is calculated using the maximization geometric mean rate technique. This shows that when the distance between adjacent RIS elements is d0 = 2λ, the channel fading between RIS elements is approximately uncorrelated. Fig.17 As shown, when the distance between adjacent RIS elements is reduced, the system performance decreases.

[0260] Fig.18 The sum rate R for different power allocation techniques (eg, in the case of average received SINRρ=-25dB) is shown. sum , minimum rate R min , geometric mean rate R GM Example of simulation comparison with the number N of RIS elements. Fig.18 As shown in FIG. 1 , for different power allocation techniques, the sum rate, minimum rate and geometric mean rate can be compared with the number N of RIS elements, where the average received SINRρ = -25 dB. Fig.18 As shown, in terms of sum rate and geometric mean rate, the maximizing geometric mean rate technique may tend to become similar to (e.g., equivalent to) the maximizing minimum rate technique when the number N of RIS elements is small, and may tend to the maximizing sum rate technique when the number N of RIS elements is large. min In terms of performance, the maximizing minimum rate technique achieves the best performance, while the maximizing sum rate technique produces the worst performance.

[0261] Fig.19 1 shows the symbol error probability P for various power allocation techniques (eg, the three power allocation techniques described in one or more examples herein). e Example of simulation comparison with the average received SINRρ. Fig.19 As shown, for these three power allocation techniques, the symbol error probability P eCompared with the average received SINRρ, it is shown that in the low SINR area (e.g., ρ<-10dB), the SEP performance (e.g., symbol error probability performance) of the maximization and rate method is slightly better than the other two methods. Because in this low SINR area, some or all users may have poor SEP performance, where in the maximization and rate technology, more power is allocated to users with relatively good conditions to ensure that these users can recover information in relatively good conditions. However, in the high SINR area (e.g., ρ>0dB), the SEP performance of the maximization minimum rate technology may be the best, while the SEP performance of the maximization and rate technology may be the worst. It can be illustrated that in the high SINR area, users (e.g., all users) have good conditions overall, and the SEP performance may be mainly determined by users with relatively poor conditions. The maximization minimum rate technology can allocate more power to users with poor conditions, while the maximization and rate technology can allocate power approximately uniformly to one or more (e.g., all) users.

[0262] Multi-user transmission utilizing OFDM may be disclosed herein.RIS / RHS assisted transmission utilizing OFDM may be disclosed herein.

[0263] As an example, for a system with L subcarriers and a cyclic prefix of length L cp OFDM symbol, the modulated information s in the lth subcarrier l and the pre-decoding matrix P in the lth carrier l Can be expressed as and P l ∈C N ×K N may represent the number of RIS elements, and K may represent the number of users. The signal transmitted at the RIS element in the frequency domain (expressed as ) can be determined, for example, using Equation 39.

[0264]

[0265] where Λ l =diag{λ l,1 ,λ l,2 ,…,λ l,K} is the power allocation matrix. k represents the power ratio allocated to the kth user and satisfies the condition, such as λ1+λ2+…+λ K = 1, and Es represents the transmitted power in the case of active RIS or RHS, or the impulse signal power in the case of passive RIS. The signal transmitted at the RIS element in the time domain (expressed as ) can be determined, for example, using equation 40.

[0266]

[0267] where F′ L represents the L×L inverse DFT matrix. The cyclic prefix length can be added to the above formula to determine the signal sent at the RIS element in the time domain. For example, by adding L cp Adding a cyclic prefix to each symbol yields Equation 41.

[0268]

[0269] The signal received at the kth user (eg, in the time domain) in the lth subcarrier (denoted as y l,k ) can be determined, for example, using equation 42.

[0270]

[0271] in is additive noise, where is the noise power, and the time domain channel from RIS to the kth user is expressed as And its time domain delay taps are expressed as And τ k represents the delay tap. The frequency of the channel from the RIS to the kth user in the lth subcarrier (expressed as ) can be determined, for example, using Equation 43.

[0272]

[0273] where F L represents the L×L discrete Fourier transform (DFT), and the full matrix is ​​expressed as and is a zero matrix. In the time domain, the symbol and noise received at the lth subcarrier can be expressed as y l =[y l,1 ,y l,2 ,…,y l,k ] T and v l =[v l,1 ,v l,2 ,…,v l,K ] T .

[0274] The signal of the kth user received in the lth subcarrier (e.g., in the frequency domain) It can be determined, for example, using one or more equations in a series of equations as shown in Equation 44.

[0275]

[0276] in represents the frequency domain additive noise at the kth user in the lth subcarrier, which follows In the frequency domain, the channel model in (eg, each) subcarrier may be determined using, for example, Equation 45.

[0277]

[0278] Precoding using OFDM may be disclosed herein. In one or more examples herein, precoding may be applied to a subcarrier (each subcarrier) prior to transmission. As an example precoding, a zero-forcing precoding method may be employed, while other precoding schemes may also be applicable. The ZF precoding matrix in the l-th subcarrier may be determined, for example, using Equation 46.

[0279]

[0280] where p l,k for The kth column of , and a constant parameter ξ may be used, for example, to ensure that the passive beamforming satisfies the condition, for example, 0≤β l,n ≤1. The reflection coefficient Φ in the lth subcarrier l It can be determined, for example, using Equation 47.

[0281]

[0282] where s l,k is the M-ary PSK information symbol or M-ary QAM information symbol of the k-th user in the l-th subcarrier (for example, s l,k ∈S M-PSK or l,k ∈S M-QAM ). For example, given that the magnitude of each RIS passive component is no greater than 1 (e.g., 0 ≤ β l,n ≤1), equation 48 is applicable:

[0283]

[0284] in‖·‖ ∞ is the infinite norm of the corresponding vector. In some cases (e.g., as shown in the above equation), for example, when the number of users K and the modulation order M increase, for some or all possible information symbol vectors s l For example, the reflection coefficient Φ is calculated l The amplitude of the transmitted signal in may have high computational complexity. l,k ∈S M-PSK When the PSK modulation signal s l,khas a constant envelope, so for example, based on the Cauchy-Schwarz inequality, the following constraints can be used (e.g., taken to be true), as shown in Equation 49.

[0285]

[0286] Wherein this equation is established when the modulation order M→∞. When the modulation order M→∞ (eg, this equation is established), the constraint condition can be simplified to, for example, Equation 50.

[0287]

[0288] For example, for modulation such as QAM (e.g., s l,k ∈S M-QAM ), the M-QAM modulation symbols may be normalized, for example, by the maximum amplitude in the M-QAM constellation (e.g., given that the amplitude of each RIS passive element is not greater than 1). For active RIS or RHS elements, limiting the power of each element to 1 may be skipped. The constraints (e.g., ≤ 1) in the above equations may be further simplified to, for example, Equation 51.

[0289]

[0290] For M-PSK modulation, ξ may satisfy Equation 52, for example.

[0291]

[0292] For M-QAM modulation, ξ may, for example, satisfy Equation 53.

[0293]

[0294] OFDM transmission may be combined with one or more examples herein. Simulation results using OFDM transmission may be disclosed herein (e.g., OFDM with L=64 subcarriers and a cyclic prefix length of L_cp=16, such as Figure 20 to Figure 23 ). Figure 20 to Figure 23 In the example shown, the channel from the RIS to the kth user is connected to the delay taps τ1=τ2=…=τ K =8, and the number of subcarriers is N fft = L = 64, the number of symbols in each cyclic prefix is ​​L cp =16, and for l=1,2,…,L, the power distribution is

[0295] Fig. 20An example of comparison of BER performance with average received SNR p using different modulation schemes (eg, where the number of users K=4 and the number of RIS elements N=256) is shown. Fig. 20 The example in shows that the QAM scheme outperforms the PSK scheme at the same modulation order. Fig. 20 The example in shows that as the modulation order increases, the BER performance becomes worse due to the increase in information bits transmitted.

[0296] Fig.21 An example of comparison of BER performance with average received SNR p for different numbers of users K (eg, for a case where the number of RIS elements N=256 and the modulation schemes are 16-PSK and 16-QAM, respectively) is shown. Fig.21 The example in shows that, for example, when the number of users increases, a higher received SNR may be required to ensure the same BER performance requirement. The power impacting the RIS can be split to support multiple users.

[0297] Fig. 22 An example of comparison of BER performance and average received SNR p for different numbers N of RIS elements (eg, for the number of users K=4 and the modulation schemes 16-PSK and 16-QAM, respectively) is shown. Fig. 22 The example in shows that doubling the number of RIS elements can achieve an SNR gain of approximately 6 dB. -5 For example, when the number of RIS elements is N=256, the 16-PSK scheme and the 16-QAM scheme may require a received SNR of -1dB and 1dB, respectively. For example, when the number of RIS elements is increased to N=512, the 16-PSK scheme and the 16-QAM scheme may require a received SNR of -7dB and -5dB, respectively, to meet the same BER performance requirement.

[0298] Fig.23 An example of BER performance versus average received SNRρ in a RIS-based transmitter and a MIMO example (eg, conventional massive MIMO) is shown, where the number of users is K=1 and the modulation schemes are 16-PSK and 16-QAM, respectively. Fig.23 The example in shows that a RIS-based transmitter with N = 128 passive reflective elements outperforms a transmitter with N RF = 32 RF chains. A RIS-based transmitter with N = 256 passive reflective elements outperforms a transmitter with N RF= Some MIMO (eg, conventional all-digital massive MIMO) with 64 RF chains. A single RF chain (eg, only a single RF chain) may be equipped in the example RIS-based transmitter herein, which is efficient, eg, from a hardware complexity perspective.

[0299] Although the features and elements described above are described in particular combinations, each feature or element may be used alone without the other features and elements of the preferred embodiments, or in various combinations with or without the other features and elements.

[0300] Although the implementation described herein may consider 3GPP specific protocols, it should be understood that the implementation described herein is not limited to such scenarios and is applicable to other wireless systems. For example, although the solution described herein considers LTE, LTE-A, New Radio (NR) or 5G specific protocols, it should be understood that the solution described herein is not limited to such scenarios and is also applicable to other wireless systems.

[0301] The processes described above may be implemented in a computer program, software, and / or firmware incorporated in a computer-readable medium for execution by a computer and / or processor. Examples of computer-readable media include, but are not limited to, electronic signals (sent 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, magnetic media (such as, but not limited to, built-in hard disks and removable disks), magneto-optical media, and / or optical media (such as compact disk (CD)-ROM disks and / or digital versatile disks (DVDs)). A processor associated with the software may be used to implement a radio frequency transceiver for a WTRU, a terminal, a base station, an RNC, and / or any host computer.

Claims

1. A wireless transmit / receive unit (WTRU), the wireless transmit / receive unit (WTRU) comprising: A processor, the processor being configured to: receiving a channel state information reference signal (CSI-RS) from a transmitter associated with a reconfigurable smart surface (RIS); determining channel vector information associated with a first subset of elements of the RIS based on the CSI-RS; determining channel vector information associated with a second subset of elements of the RIS based on the channel vector information associated with the first subset of elements of the RIS; generating CSI reporting parameters based on the channel vector information associated with the second subset of elements of the RIS; as well as The CSI reporting parameters are transmitted.

2. The WTRU of claim 1 , wherein the processor is further configured to: Determining a channel matrix associated with the RIS, wherein the channel matrix includes the channel vector information associated with the first subset of elements of the RIS and the channel vector information associated with the second subset of elements of the RIS, and wherein the CSI report parameters are generated using the channel matrix associated with the RIS.

3. The WTRU of claim 1 , wherein the CSI reporting parameters are virtual CSI reporting parameters, and the processor is further configured to: receiving configuration information associated with the RIS, wherein the configuration information indicates a configuration associated with the first subset of elements of the RIS and a configuration associated with the second subset of elements of the RIS; determining a first channel matrix based on the channel vector information associated with the first subset of elements of the RIS; as well as A second channel matrix is ​​determined based on the first channel matrix and the configuration information, wherein the second channel matrix includes the channel vector information associated with the first subset of elements of the RIS and the channel vector information associated with the second subset of elements of the RIS, and wherein the second channel matrix is ​​used to generate the virtual CSI report parameters.

4. The WTRU according to claim 3, wherein the first channel matrix includes first channel matrix coefficients, the first channel matrix coefficients indicating channel vector information associated with elements in the first subset of elements of the RIS, and wherein the second channel matrix includes the first channel matrix coefficients and second channel matrix coefficients, the second channel matrix coefficients indicating channel vector information associated with elements in the second subset of elements of the RIS.

5. The WTRU of claim 1 , wherein the processor is further configured to: receiving configuration information associated with the RIS, wherein the configuration information indicates active elements of the RIS and non-active elements of the RIS, wherein the first subset of elements includes the active elements of the RIS and the second subset of elements includes the non-active elements of the RIS, wherein the CSI-RS is associated with the active elements of the RIS; and Channel measurements limited to the first subset of elements including the active elements of the RIS are performed based on one or more CSI-RSs including the CSI-RS, wherein the channel vector information associated with the first subset of elements of the RIS is determined based on the channel measurements.

6. The WTRU of claim 5, wherein the CSI reporting parameter is a first CSI reporting parameter, and the processor is further configured to: determining second CSI reporting parameters using the channel measurements restricted to the first subset of elements; and At least one of the first CSI reporting parameter or the second CSI reporting parameter is transmitted.

7. The WTRU of claim 1 , wherein the processor is further configured to: receiving block partition information associated with the RIS, wherein the block partition information indicates that the RIS includes a first block of elements and a second block of elements, wherein the first block of elements includes the first subset of elements and the second subset of elements, wherein the first subset of elements includes active elements associated with the first block of elements and the second subset of elements includes non-active elements associated with the first block of elements, and wherein the CSI reporting parameters are further generated based on the block partition information and are associated with the first block of elements.

8. The WTRU of claim 1 , wherein the processor is further configured to: receiving a request to communicate using RIS-based routing; receiving an indication of a plurality of transmit ports; and The RIS-based transmission is decoded based on the indication of the plurality of transmission ports.

9. A method performed by a wireless transmit / receive unit (WTRU), the method comprising: receiving a channel state information reference signal (CSI-RS) from a transmitter associated with a reconfigurable smart surface (RIS); determining channel vector information associated with a first subset of elements of the RIS based on the CSI-RS; determining channel vector information associated with a second subset of elements of the RIS based on the channel vector information associated with the first subset of elements of the RIS; generating CSI reporting parameters based on the channel vector information associated with the second subset of elements of the RIS; as well as The CSI reporting parameters are transmitted.

10. The method according to claim 9, further comprising: Determining a channel matrix associated with the RIS, wherein the channel matrix includes the channel vector information associated with the first subset of elements of the RIS and the channel vector information associated with the second subset of elements of the RIS, and wherein the CSI report parameters are generated using the channel matrix associated with the RIS.

11. The method according to claim 9, wherein the CSI reporting parameter is a virtual CSI reporting parameter, and the method further comprises: receiving configuration information associated with the RIS, wherein the configuration information indicates a configuration associated with the first subset of elements of the RIS and a configuration associated with the second subset of elements of the RIS; determining a first channel matrix based on the channel vector information associated with the first subset of elements of the RIS; as well as A second channel matrix is ​​determined based on the first channel matrix and the configuration information, wherein the second channel matrix includes the channel vector information associated with the first subset of elements of the RIS and the channel vector information associated with the second subset of elements of the RIS, and wherein the second channel matrix is ​​used to generate the virtual CSI report parameters.

12. A method according to claim 11, wherein the first channel matrix includes first channel matrix coefficients, and the first channel matrix coefficients indicate channel vector information associated with elements in the first subset of elements of the RIS, and wherein the second channel matrix includes the first channel matrix coefficients and second channel matrix coefficients, and the second channel matrix coefficients indicate channel vector information associated with elements in the second subset of elements of the RIS.

13. The method according to claim 9, further comprising: receiving configuration information associated with the RIS, wherein the configuration information indicates active elements of the RIS and non-active elements of the RIS, wherein the first subset of elements includes the active elements of the RIS and the second subset of elements includes the non-active elements of the RIS, wherein the CSI-RS is associated with the active elements of the RIS; as well as Channel measurements limited to the first subset of elements including the active elements of the RIS are performed based on one or more CSI-RSs including the CSI-RS, wherein the channel vector information associated with the first subset of elements of the RIS is determined based on the channel measurements.

14. The method according to claim 13, wherein the CSI reporting parameter is a first CSI reporting parameter, and the method further comprises: determining second CSI reporting parameters using the channel measurements restricted to the first subset of elements; as well as At least one of the first CSI reporting parameter or the second CSI reporting parameter is transmitted.

15. The method according to claim 9, further comprising: receiving block partition information associated with the RIS, wherein the block partition information indicates that the RIS includes a first block of elements and a second block of elements, wherein the first block of elements includes the first subset of elements and the second subset of elements, wherein the first subset of elements includes active elements associated with the first block of elements and the second subset of elements includes non-active elements associated with the first block of elements, and wherein the CSI reporting parameters are further generated based on the block partition information and are associated with the first block of elements.

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