Control Information and TCI for Reconfigurable Intelligent Surfaces

Abstract

Control information and a transmission configuration indicator (TCI) are provided for a reconfigurable intelligent surface (RIS). A wireless transmit / receive unit (WTRU) may receive a first physical downlink shared channel (PDSCH) transmission using a first TCI state associated with a base station and a second TCI state associated with a first RIS mode. The WTRU may perform reference signal measurements associated with the RIS. The WTRU may determine an interference level based on the reference signal measurement values. The WTRU may determine a second RIS mode based on the interference level. The WTRU may transmit a message to the base station, where the message indicates the second RIS mode. The WTRU may receive an indication of a third RIS mode associated with a third TCI state associated with the base station. The WTRU may receive a second PDSCH transmission using the third TCI state.

Description

Technical Field

[0001] (Cross - Reference to Related Applications) This application claims the benefit of U.S. Provisional Patent Application No. 63 / 336,063, filed on April 28, 2022, the disclosure of which is hereby incorporated by reference in its entirety.

Background Art

[0002] Mobile communications using wireless communication are continuously evolving. The fifth generation may be referred to as 5G. Previous (conventional) generations of mobile communications can be, for example, the fourth generation (4G) long term evolution (LTE).

Summary of the Invention

[0003] A system, method, and means for control information for a reconfigurable intelligent surface (RIS) and for a transmission configuration indicator (TCI) are described herein.

[0004] A device (e.g., a wireless transmit / receive unit (WTRU)) may receive a first physical downlink shared channel (PDSCH) transmission using a first transmission configuration indicator (TCI) state associated with a base station and using a second TCI state associated with a first reconfigurable intelligent surface (RIS) mode. The device may perform reference signal measurements associated with the RIS. The device may determine an interference level based on the reference signal measurement values. The device may determine a second RIS mode based on the interference level. The device may transmit a message to the base station. The message may indicate the second RIS mode. The device may receive an indication of a third RIS mode associated with a third TCI state. The third TCI state may be associated with the base station. The device may receive a second PDSCH transmission using the third TCI state.

[0005] On the condition that the interference level is greater than an interference threshold, the second RIS mode may be determined to be an absorption mode. On the condition that the third RIS mode indicates an absorption mode, the device may deactivate a second TCI state associated with the first RIS mode. The message may indicate at least one of the reference signal measurement values or the interference level. The third RIS mode may be different from the second RIS mode. The device may activate the third TCI state based on the indication of the third RIS mode. The device may receive configuration information. The configuration information may indicate the respective associations between a plurality of TCI states and RIS operation modes. The indication of the third RIS mode may be received in a group common physical downlink control channel (GC-PDCCH) transmission. BRIEF DESCRIPTION OF THE DRAWINGS

[0006]

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DETAILED DESCRIPTION OF THE INVENTION

[0007] Exemplary network for implementing the embodiment FIG. 1A is a diagram illustrating an exemplary communication system 100 in which one or more of the disclosed embodiments may be implemented. The communication system 100 may be a multi-access system that provides content such as voice, data, video, messaging, broadcast, etc. to a plurality of wireless users. The communication system 100 may enable a plurality of wireless users to access such content through sharing of system resources including wireless bandwidth. For example, the communication system 100 may use one or more channel access methods such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single-carrier FDMA (SC-FDMA), zero-tail unique-word DFT-Spread OFDM (ZT UW DTS-s OFDM), unique word OFDM (UW-OFDM), resource block filtered OFDM, filter bank multicarrier (FBMC), etc.

[0008] As shown in Figure 1A, communication system 100 can 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, although it will 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 can be any type of device configured to operate and / or communicate in a wireless environment. By way of example, the WTRUs 102a, 102b, 102c, 102d, any of which may be referred to as a "station" and / or "STA", can be configured to transmit and / or receive wireless signals and can be user equipment (UE), mobile station, fixed subscriber unit or mobile subscriber unit, subscriber-based unit, pager, cellular phone, personal digital assistant (PDA), smartphone, laptop, netbook, personal computer, wireless sensor, hotspot or Mi-Fi device, Internet of Things (IoT) device, watch or other wearable, head-mounted display (HMD), vehicle, drone, medical device and application (e.g., for remote surgery), industrial device and application (e.g., robots and / or other wireless devices operating in an industrial and / or automated processing chain context), home appliance device, device operating in a commercial wireless network and / or industrial wireless network, etc. Any of the WTRUs 102a, 102b, 102c, and 102d can be interchangeably referred to as a UE.

[0009] The communication system 100 may also include base station 114a and / or base station 114b. Each of base stations 114a, 114b may be any type of device configured to wirelessly interface with at least one of WTRUs 102a, 102b, 102c, 102d to facilitate access to one or more communication networks such as CN106 / 115, the Internet 110, and / or other network 112. By way of example, base stations 114a, 114b may be a base transceiver station (BTS), Node B, eNode B, Home Node B, Home eNode B, gNB, NR Node B, a site controller, an access point (AP), a wireless router, etc. Although base stations 114a, 114b are each depicted as a single element, it will be understood that base stations 114a, 114b may include any number of interconnected base stations and / or network elements.

[0010] Base station 114a may be part of RAN 104 / 113 and may also include other base stations and / or network elements (not shown), such as a base station controller (BSC), a radio network controller (RNC), a relay node, etc. Base station 114a and / or base station 114b may be configured to transmit and / or receive radio signals at one or more carrier frequencies, which may be referred to as a cell (not shown). These frequencies may be in the licensed spectrum, the unlicensed spectrum, or a combination of the licensed and unlicensed spectra. The cell may provide coverage of wireless services to a specific geographic area that 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. Thus, in one embodiment, base station 114a may include three transceivers, i.e., one transceiver per sector of the cell. In one embodiment, base station 114a may use multiple-input multiple output (MIMO) technology and may utilize multiple transceivers per sector of the cell. For example, beamforming may be used to transmit and / or receive signals in a desired spatial direction.

[0011] Base stations 114a, 114b may communicate with one or more of WTRUs 102a, 102b, 102c, 102d via 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.). Air interface 116 may be established using any suitable radio access technology (RAT).

[0012] More specifically, as described above, the communication system 100 can be a multiple access system and can use one or more channel access methods such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, etc. For example, the base stations 114a within RAN104 / 113, and WTRUs 102a, 102b, 102c may implement radio technologies such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which can establish air interfaces 115 / 116 / 117 using wideband CDMA (WCDMA). WCDMA may include communication protocols such as High-Speed Packet Access (HSPA) and / or Evolved HSPA (HSPA+). HSPA may include High-Speed Downlink Packet Access (HSDPA) and / or High-Speed UL Packet Access (HSUPA).

[0013] In one embodiment, the base station 114a and WTRUs 102a, 102b, 102c may implement radio technologies such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which can establish the air interface 116 using Long Term Evolution (LTE), and / or LTE-Advanced (LTE-A), and / or LTE-Advanced Pro (LTE-A Pro).

[0014] In one embodiment, the base station 114a, and WTRUs 102a, 102b, 102c may implement radio technologies such as NR radio access, which can establish the air interface 116 using New Radio (NR) technology.

[0015] In one embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement multiple radio access technologies. For example, the base station 114a and the WTRUs 102a, 102b, 102c may implement LTE radio access and NR radio access together, for example, using the dual connectivity (DC) principle. Accordingly, the air interface utilized by the WTRUs 102a, 102b, 102c may be characterized by transmissions sent to / from multiple types of radio access technologies and / or multiple types of base stations (e.g., eNBs and gNBs).

[0016] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement wireless technologies such as IEEE 802.11 (i.e., Wireless Fidelity (WiFi)), IEEE 802.16 (i.e., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), IS-95, IS-856, Global System for Mobile communications (GSM), Enhanced Data rates for GSM Evolution (EDGE), GSM EDGE (GERAN), etc.

[0017] The base station 114b in FIG. 1A may be, for example, a wireless router, a home node B, a home eNode B, or an access point, and may utilize any suitable RAT to facilitate wireless connection in a local area such as an office, a home, a vehicle, a campus, an industrial facility, an aerial corridor (for example, for use by a drone), a road, etc. In one embodiment, the base station 114b and the WTRUs 102c, 102d may implement a wireless technology such as IEEE 802.11 to establish a wireless local area network (WLAN). In one embodiment, the base station 114b and the WTRUs 102c, 102d may implement a wireless technology such as IEEE 802.15 to establish a wireless personal area network (WPAN). In yet another embodiment, the base station 114b and the WTRUs 102c, 102d may utilize a cellular-based RAT (for example, WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.) to establish a pico cell or a femto cell. As shown in FIG. 1A, the base station 114b may have a direct connection to the Internet 110. Thus, the base station 114b may not need to access the Internet 110 via the CN 106 / 115.

[0018] RAN 104 / 113 can communicate with CN 106 / 115, which can be any type of network configured to provide voice, data, applications, and / or voice over internet protocol (VoIP) services to one or more of WTRUs 102a, 102b, 102c, 102d. The data can have various quality of service (QoS) requirements, such as different throughput requirements, latency requirements, error tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, etc. CN 106 / 115 can provide call control, billing services, mobile location-based services, prepaid calls, internet connectivity, video distribution, etc., and / or can implement high-level security functions such as user authentication. Although not shown in Figure 1A, it will be understood that RAN 104 / 113 and / or CN 106 / 115 can communicate directly or indirectly with other RANs that use the same radio access technology (RAT) or a different RAT than RAN 104 / 113. For example, in addition to being connected to a RAN 104 / 113 that can utilize New Radio (NR) radio technology, CN 106 / 115 can also communicate with another RAN (not shown) using GSM, UMTS, CDMA2000, WiMAX, E-UTRA, or WiFi radio technology.

[0019] CN106 / 115 may also function as a gateway for WTRU102a, 102b, 102c, 102d to access the PSTN108, the Internet 110, and / or other networks 112. The PSTN108 may include a circuit-switched telephone network that provides a plain old telephone service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices, and these networks and devices use a common communication protocol such as the transmission control protocol (TCP), the user datagram protocol (UDP), and / or the internet protocol (IP) of the TCP / IP internet protocol suite. The network 112 may include a wired communication network and / or a wireless communication network that is owned and / or operated by another service provider. For example, the network 112 may include another CN connected to one or more RANs that may use the same RAT or a different RAT as the RAN104 / 113.

[0020] Some or all of the WTRU102a, 102b, 102c, 102d in the communication system 100 may include a multimode function (e.g., the WTRU102a, 102b, 102c, 102d may include multiple transceivers for communicating with different wireless networks via different wireless links). For example, the WTRU102c shown in Figure 1A may be configured to communicate with a base station 114a that may use a cellular-based wireless technology and a base station 114b that may use IEEE802 wireless technology.

[0021] Figure 1B is a system diagram illustrating an exemplary WTRU 102. As shown in Figure 1B, 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, a non-removable memory 130, a removable memory 132, a power source 134, a global positioning system (GPS) chipset 136, and / or other peripheral devices 138. It will be understood that the WTRU 102 may include any partial combination of the foregoing elements while remaining consistent with one embodiment.

[0022] The processor 118 may be a general-purpose processor, a dedicated processor, a conventional processor, a digital signal processor (DSP), a plurality of microprocessors, one or more microprocessors associated with a DSP core, a controller, a microcontroller, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) circuit, any other type of integrated circuit (IC), a state machine, etc. The processor 118 may perform signal coding, data processing, power control, input / output processing, and / or any other function 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 depicts the processor 118 and the transceiver 120 as separate components, it will be understood that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip.

[0023] The transmit / receive element 122 may be configured to transmit or receive signals to / from a base station (e.g., base station 114a) via the air interface 116. For example, in one embodiment, the transmit / receive element 122 may be an antenna configured to transmit and / or receive RF signals. In one embodiment, the transmit / receive element 122 may be an emitter / detector configured to transmit and / or receive, for example, IR signals, UV signals, or visible light signals. In yet another embodiment, the transmit / receive element 122 may be configured to transmit and / or receive both RF signals and optical signals. It will be understood that the transmit / receive element 122 may be configured to transmit and / or receive any combination of wireless signals.

[0024] Although the transmit / receive element 122 is depicted in FIG. 1B as a single element, the WTRU 102 may include any number of transmit / receive elements 122. More specifically, the WTRU 102 may utilize 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 via the air interface 116.

[0025] The transceiver 120 may be configured to modulate signals transmitted by the transmit / receive element 122 and demodulate signals received by the transmit / receive element 122. As noted above, the WTRU 102 may have a multimode functionality. Thus, the transceiver 120 may include multiple transceivers to enable the WTRU 102 to communicate via multiple RATs such as, for example, NR and IEEE 802.11.

[0026] The processor 118 of the WTRU 102 can be coupled to the speaker / microphone 124, keypad 126, and / or display / touchpad 128 (e.g., a liquid crystal display (LCD) display unit or an organic light-emitting diode (OLED) display unit) and can receive data input by a user from these. The processor 118 can also output user data to the speaker / microphone 124, keypad 126, and / or display / touchpad 128. In addition, the processor 118 can access information from and store data in any suitable type of memory, such as the non-removable memory 130 and / or the removable memory 132. The non-removable memory 130 can include random-access memory (RAM), read-only memory (ROM), a hard disk, or any other type of memory storage device. The removable memory 132 can include a subscriber identity module (SIM) card, a memory stick, a secure digital (SD) memory card, etc. In other embodiments, the processor 118 can 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).

[0027] The processor 118 may receive power from the power supply 134 and may be configured to distribute and / or control power to other components in the WTRU 102. The power supply 134 may be any suitable device for powering the WTRU 102. For example, the power supply 134 may include one or more dry batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, and the like.

[0028] 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 instead of, information from the GPS chipset 136, the WTRU 102 may receive location information from a base station (e.g., base stations 114a, 114b) via the air interface 116 and / or may determine its location based on the timing of signals received from two or more neighboring base stations. It will be understood that the WTRU 102 may obtain location information by any suitable location determination method while remaining consistent with one embodiment.

[0029] Processor 118 may be further coupled to other peripheral devices 138, which may include one or more software and / or hardware modules that provide additional features, functions, and / or wired or wireless connections. For example, the peripheral devices 138 may include an accelerometer, an electronic compass, a satellite transceiver, a digital camera (for photos and / or videos), a universal serial bus (USB) port, a vibration device, a television transceiver, a hands-free headset, a Bluetooth® module, a frequency modulated (FM) radio unit, a digital music player, a media player, a video game player module, an Internet browser, a virtual reality and / or augmented reality (VR / AR) device, an activity tracker, and the like. The peripheral devices 138 may include one or more sensors, which may be one or more of a gyroscope, an accelerometer, a Hall effect sensor, a magnetometer, an orientation sensor, a proximity sensor, a temperature sensor, a time sensor, a geolocation sensor, an altimeter, a light sensor, a touch sensor, a magnetometer, a barometer, a gesture sensor, a biometric sensor, and / or a humidity sensor.

[0030] The WTRU 102 may include a full-duplex radio in which some or all of the transmission and reception of signals associated with a particular subframe (e.g., for both UL (e.g., for transmission) and downlink (e.g., for reception)) may be parallel and / or simultaneous. The full-duplex radio may include an interference management unit for reducing and / or substantially eliminating self-interference either via hardware (e.g., choke) or via signal processing through a processor (e.g., a separate processor (not shown) or via processor 118). In one embodiment, the WRTU 102 may include a half-duplex radio for the transmission and reception of any of some or all of the signals (e.g., associated with a particular subframe for either UL (e.g., for transmission) or downlink (e.g., for reception)).

[0031] Figure 1C is a system diagram illustrating RAN 104 and CN 106 according to one embodiment. As described above, RAN 104 may use E-UTRA radio technology to communicate with WTRUs 102a, 102b, 102c via air interface 116. RAN 104 may also communicate with CN 106.

[0032] RAN 104 may include eNodeBs 160a, 160b, 160c, although it will be understood that RAN 104 may include any number of eNodeBs while remaining consistent with one embodiment. Each of eNodeBs 160a, 160b, 160c may include one or more transceivers for communicating with WTRUs 102a, 102b, 102c via air interface 116. In one embodiment, eNodeBs 160a, 160b, 160c may implement MIMO technology. Thus, eNodeB 160a, for example, may transmit wireless signals to and / or receive wireless signals from WTRU 102a using multiple antennas.

[0033] Each of eNodeBs 160a, 160b, 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, user scheduling in UL and / or DL, etc. As shown in Figure 1C, eNodeBs 160a, 160b, 160c may communicate with each other via the X2 interface.

[0034] CN 106 shown in Figure 1C may include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (or PGW) 166. Although each of the foregoing elements is depicted as part of CN 106, it will be understood that any of these elements may be owned and / or operated by an entity other than a CN operator.

[0035] The MME 162 can be connected to each of the eNodeBs 162a, 162b, 162c in the RAN 104 via the S1 interface and can function as a control node. For example, the MME 162 can authenticate users of the WTRUs 102a, 102b, 102c, activate / deactivate bearers, select a specific serving gateway during the initial attach of the WTRUs 102a, 102b, 102c, etc. The MME 162 can provide control plane functions for switching between the RAN 104 and other RANs (not shown) using other radio technologies such as GSM and / or WCDMA.

[0036] The SGW 164 can be connected to each of the eNodeBs 160a, 160b, 160c in the RAN 104 via the S1 interface. The SGW 164 can generally route and transfer user data packets between the WTRUs 102a, 102b, 102c. The SGW 164 can perform other functions such as the function of anchoring the user plane during handover between eNodeBs, the function of triggering paging when DL data is available to the WTRUs 102a, 102b, 102c, and the function of managing and storing the context of the WTRUs 102a, 102b, 102c.

[0037] The SGW 164 can be connected to the PGW 166, and the PGW 166 can provide access to a packet switched network such as the Internet 110 to the WTRUs 102a, 102b, 102c to facilitate communication between the WTRUs 102a, 102b, 102c and IP-enabled devices.

[0038] CN106 can facilitate communication with other networks. For example, CN106 can provide access to a circuit-switched network such as PSTN108 to WTRU102a, 102b, 102c to facilitate communication between the WTRU102a, 102b, 102c and a conventional landline communication device. For example, CN106 can include or communicate with an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that functions as an interface between CN106 and PSTN108. Additionally, CN106 can provide WTRU102a, 102b, 102c with access to other networks 112 that can include other wired and / or wireless networks owned and / or operated by other service providers.

[0039] The WTRU is described as a wireless terminal in FIGS. 1A - 1D, but in certain representative embodiments, it is contemplated that such a terminal can use a wired communication interface (e.g., temporarily or permanently) with a communication network.

[0040] In a representative embodiment, other network 112 can be a WLAN.

[0041] A WLAN in infrastructure basic service set (BSS) mode may have an access point (AP) of the BSS and one or more stations (STAs) associated with the AP. The AP may have access or an interface to another type of wired network / wireless network that carries traffic entering and / or exiting the distribution system (DS) or BSS. Traffic destined for an STA that originates outside the BSS may arrive through the AP and may be sent to the STA. Traffic originating from an STA and destined for a destination outside the BSS may be sent to the AP so as to be sent to their respective destinations. Traffic between STAs within the BSS may be sent, for example, through the AP. The source STA may send the traffic to the AP, and the AP may send the traffic to the destination STA. Traffic between STAs within the BSS may be considered and / or referred to as peer-to-peer traffic. Peer-to-peer traffic may be sent between the source STA and the destination STA (e.g., directly between them) using direct link setup (DLS). In certain representative embodiments, the DLS may use 802.11e DLS or 802.11z tunneled DLS (TDLS). A WLAN using independent BSS (IBSS) mode may not have an AP, and STAs within or using the IBSS (e.g., all of the STAs) may communicate directly with each other. The IBSS mode of communication may be referred to herein as the "ad hoc" communication mode.

[0042] When using the 802.11ac infrastructure operation mode or a similar operation mode, the AP may transmit beacons on a fixed channel such as the primary channel. The primary channel may be of a fixed width (e.g., a 20 MHz wide bandwidth) or a width dynamically set via signaling. The primary channel may be the operating channel of the BSS, but may be used by the STA to establish a connection with the AP. In certain representative embodiments, for example, in an 802.11 system, Carrier Sense Multiple Access with Collision Avoidance (CSMA / CA) may be implemented. In the case of CSMA / CA, STAs including the AP (e.g., all STAs) may sense the primary channel. If the primary channel is sensed / detected and / or determined to be busy by a particular STA, the particular STA may back off. Only one STA (e.g., only one station) may transmit at any given time in a given BSS.

[0043] A High Throughput (HT) STA may use a 40 MHz wide channel for communication, and this 40 MHz wide channel may be formed, for example, via a combination of a primary 20 MHz channel and an adjacent or non - adjacent 20 MHz channel.

[0044] A Very High Throughput (VHT) STA can support channels with widths of 20 MHz, 40 MHz, 80 MHz, and / or 160 MHz. A 40 MHz and / or 80 MHz channel can be formed by combining a plurality of adjacent 20 MHz channels. A 160 MHz channel can be formed by combining eight consecutive 20 MHz channels or by combining two non-adjacent 80 MHz channels, which can be referred to as an 80+80 configuration. In the case of the 80+80 configuration, after channel encoding, the data can pass through a segment parser that can divide the data into two streams. The Inverse Fast Fourier Transform (IFFT) process and the time-domain process can be performed separately for each stream. The streams can be mapped to two 80 MHz channels, and the data can be transmitted by the transmitting STA. At the receiver of the receiving STA, the operations described above for the 80+80 configuration can be reversed, and the combined data can be sent to the Medium Access Control (MAC).

[0045] The sub-1 GHz operating mode is supported by 802.11af and 802.11ah. The channel operating bandwidth and carrier frequency are reduced in 802.11af and 802.11ah compared to those used in 802.11n and 802.11ac. 802.11af supports bandwidths of 5 MHz, 10 MHz, and 20 MHz in the TV White Space (TVWS) spectrum, and 802.11ah supports bandwidths of 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz using non-TVWS spectrum. According to an exemplary embodiment, 802.11ah may support meter type control / machine type communication, such as MTC devices within a macro communication range area. The MTC device may have limited capabilities, including support for certain capabilities, e.g., support for certain and / or limited bandwidths (e.g., supporting only these). The MTC device may include a battery having a battery life above a threshold (e.g., to maintain a very long battery life).

[0046] A WLAN system that can support multiple channels and channel bandwidths such as 802.11n, 802.11ac, 802.11af, and 802.11ah includes 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 can be set and / or limited by an STA from among all STAs operating in a BSS that supports the minimum bandwidth operation mode. In an example of 802.11ah, the primary channel can be 1 MHz wide for an STA (e.g., an MTC type device) that supports the 1 MHz mode (e.g., supports only this) even when the AP and other STAs in the BSS support 2 MHz, 4 MHz, 8 MHz, 16 MHz, and / or other channel bandwidth operation modes. Carrier sensing and / or Network Allocation Vector (NAV) setting can depend on the status of the primary channel. For example, due to an STA transmitting to an AP (supporting only the 1 MHz operation mode), if the primary channel is busy, most of the frequency band remains in an operation pause and, even if it may be available, the entire available frequency band can be considered busy.

[0047] In the United States, the available frequency band that can be used by 802.11ah is 902 MHz to 928 MHz. In South Korea, the available frequency band is 917.5 MHz to 923.5 MHz. In Japan, the available frequency band is 916.5 MHz to 927.5 MHz. The total bandwidth available for 802.11ah is 6 MHz to 26 MHz depending on the country code.

[0048] Figure 1D is a system diagram illustrating RAN113 and CN115 according to one embodiment. As described above, RAN113 can use NR radio technology to communicate with WTRU102a, 102b, 102c via air interface 116. RAN113 can also communicate with CN115.

[0049] RAN 113 may include gNBs 180a, 180b, and 180c, but it should be understood that RAN 113 may include any number of gNBs while remaining consistent with one embodiment. Each of gNBs 180a, 180b, and 180c may include one or more transceivers for communicating with WTRUs 102a, 102b, and 102c via air interface 116. In one embodiment, gNBs 180a, 180b, and 180c may implement MIMO technology. For example, gNBs 180a and 108b may use beamforming to transmit signals to and / or receive signals from gNBs 180a, 180b, and 180c. Thus, gNB 180a may transmit and / or receive radio signals to and from WTRU 102a using, for example, multiple antennas. In one embodiment, gNBs 180a, 180b, and 180c may implement carrier aggregation technology. For example, gNB 180a may transmit multiple component carriers to WTRU 102a (not shown). A subset of such component carriers may be on unlicensed spectrum, while the remaining component carriers may be on licensed spectrum. In one embodiment, gNBs 180a, 180b, and 180c may implement coordinated multi-point (CoMP) technology. For example, WTRU 102a may receive coordinated transmissions from gNB 180a and gNB 180b (and / or gNB 180c).

[0050] The WTRUs 102a, 102b, and 102c may communicate with the gNBs 180a, 180b, and 180c using transmissions associated with scalable numerology. For example, the OFDM symbol interval and / or the OFDM sub-carrier interval may vary for different transmissions, different cells, and / or different portions of the radio transmission spectrum. The WTRUs 102a, 102b, and 102c may communicate with the gNBs 180a, 180b, and 180c using sub-frames or transmission time intervals (TTIs) of various or scalable lengths (e.g., including various numbers of OFDM symbols and / or having absolute times of various lengths).

[0051] gNBs 180a, 180b, and 180c may be configured to communicate with WTRUs 102a, 102b, and 102c in a stand-alone configuration and / or a non-stand-alone configuration. In a stand-alone configuration, WTRUs 102a, 102b, and 102c may communicate with gNBs 180a, 180b, and 180c without accessing other RANs (e.g., eNodeBs 160a, 160b, and 160c, etc.). In a stand-alone configuration, WTRUs 102a, 102b, and 102c may utilize one or more of gNBs 180a, 180b, and 180c as mobility anchor points. In a stand-alone configuration, WTRUs 102a, 102b, and 102c may communicate with gNBs 180a, 180b, and 180c using signals in an unlicensed band. In a non-stand-alone configuration, WTRUs 102a, 102b, and 102c may communicate with and connect to gNBs 180a, 180b, and 180c while also communicating with and connecting to another RAN such as eNodeBs 160a, 160b, and 160c. For example, WTRUs 102a, 102b, and 102c may implement a DC principle for communicating with one or more gNBs 180a, 180b, and 180c and one or more eNodeBs 160a, 160b, and 160c substantially simultaneously. In a non-stand-alone configuration, eNodeBs 160a, 160b, and 160c may function as mobility anchors for WTRUs 102a, 102b, and 102c, and gNBs 180a, 180b, and 180c may provide additional coverage and / or throughput for servicing WTRUs 102a, 102b, and 102c.

[0052] Each of gNBs 180a, 180b, and 180c can be associated with a specific cell (not shown) and can be configured to handle radio resource management decisions, handover decisions, user scheduling in UL and / or DL, support for network slicing, dual connectivity, interworking between NR and E-UTRA, routing of user plane data to user plane functions (UPFs) 184a, 184b, routing of control plane information to access and mobility management functions (AMFs) 182a, 182b, etc. As shown in FIG. 1D, gNBs 180a, 180b, and 180c can communicate with each other via the Xn interface.

[0053] CN 115 shown in FIG. 1D can include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one session management function (SMF) 183a, 183b, and optionally data networks (DNs) 185a, 185b. Although each of the foregoing elements is depicted as part of CN 115, it will be understood that any of these elements can be owned and / or operated by an entity other than the CN operator.

[0054] AMF 182a and 182b can be connected to one or more of gNBs 180a, 180b, and 180c in RAN 113 via the N2 interface and can function as control nodes. For example, AMF 182a and 182b can play roles such as authentication of users of WTRUs 102a, 102b, and 102c, support for network slicing (e.g., handling of different PDU sessions with different requirements), selection of specific SMFs 183a and 183b, management of the registration area, termination of NAS signaling, and mobility management. Network slices can be used by AMF 182a and 182b to customize the CN support for WTRUs 102a, 102b, and 102c based on the type of service being utilized by WTRUs 102a, 102b, and 102c. For example, different network slices can be established for different use cases such as services that rely on ultra-reliable low latency (URLLC) access, services that rely on enhanced massive mobile broadband (eMBB) access, and services for machine type communication (MTC) access. AMF 162 can provide control plane functions for exchange between RAN 113 and other RANs (not shown) that use other radio technologies such as non-3GPP access technologies like LTE, LTE-A, LTE-A Pro, and / or WiFi.

[0055] SMF183a and 183b can be connected to AMF182a and 182b in CN115 via the N11 interface. SMF183a and 183b can also be connected to UPF184a and 184b in CN115 via the N4 interface. SMF183a and 183b can select and control UPF184a and 184b and configure the routing of traffic passing through UPF184a and 184b. SMF183a and 183b can perform other functions such as managing and allocating UE IP addresses, managing PDU sessions, controlling policy enforcement and QoS, and providing downlink data notifications. The PDU session type can be IP-based, non-IP-based, Ethernet-based, etc.

[0056] UPF184a and 184b can be connected to one or more of gNB180a, 180b, and 180c in RAN113 via the N3 interface, thereby providing WTRU102a, 102b, and 102c with access to a packet-switched network such as the Internet 110 to facilitate communication between WTRU102a, 102b, and 102c and IP-corresponding devices. UPF184 and 184b can perform other functions such as routing and forwarding packets, enforcing user plane policies, supporting multi-home PDU sessions, handling user plane QoS, buffering downlink packets, and providing mobility anchoring.

[0057] CN115 may facilitate communication with other networks. For example, CN115 may include or communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that functions as an interface between CN115 and the PSTN 108. In addition, CN115 may provide the WTRU 102a, 102b, 102c with access to other networks 112 that may include other wired and / or wireless networks owned and / or operated by other service providers. In one embodiment, the WTRU 102a, 102b, 102c may be connected to the local data network (DN) 185a, 185b through the UPF 184a, 184b via an N3 interface to the UPF 184a, 184b and an N6 interface between the UPF 184a, 184b and the DN 185a, 185b.

[0058] Looking at FIGS. 1A - 1D and the corresponding descriptions of FIGS. 1A - 1D, one or more of the functions described herein related to one or more of the WTRU 102a - d, base stations 114a and b, eNodeB 160a - c, MME 162, SGW 164, PGW 166, gNB 180a - c, AMF 182a and b, UPF 184a and b, SMF 183a and b, DN 185a and b, and / or any other device described herein may be implemented by one or more emulation devices (not shown). An emulation device may be one or more devices configured to emulate one or more or all of the functions described herein. For example, an emulation device may be used to test other devices and / or simulate network and / or WTRU functionality.

[0059] An emulation device can be designed to implement one or more tests of other devices in a laboratory environment and / or an operator network environment. For example, one or more emulation devices can perform one or more or all functions while being fully or partially implemented and / or deployed as part of a wired and / or wireless communication network to test other devices within the communication network. One or more emulation devices can perform one or more or all functions while being temporarily implemented / deployed as part of a wired and / or wireless communication network. An emulation device can be directly coupled to another device for testing purposes and / or can use terrestrial wireless communication to conduct the test.

[0060] One or more emulation devices can perform one or more functions including all while not being implemented / deployed as part of a wired and / or wireless communication network. For example, an emulation device can be utilized in a test scenario in a test laboratory and / or in a wired and / or wireless communication network that is not deployed (e.g., for testing) to implement tests of one or more components. One or more emulation devices can be test equipment. Direct RF coupling and / or wireless communication via an RF circuit (which can include one or more antennas) can be used by the emulation device to transmit and / or receive data.

[0061] A WTRU can perform reception (e.g., physical downlink control channel (PDCCH) / physical downlink shared channel (PDSCH) reception) and / or transmission (e.g., physical uplink control channel (PUCCH) / physical uplink shared channel (PUSCH) transmission) via a reconfigurable intelligent surface (RIS) for a RIS-assisted system (e.g., based on the RIS type and / or RIS operation mode). The WTRU can be configured using reference signal (RS) resources, for example, according to the RIS type and / or RIS operation mode.

[0062] The WTRU can perform, for example, one or more of the following: receive one or more transmission configuration indicator (TCI) states and / or configuration information having an association with a RIS (e.g., based on the RIS type and / or RIS operation mode); activate a TCI state for beamforming information in a RIS-assisted system; receive a TCI indication regarding beam information for reception or transmission via the RIS; decode a physical downlink control channel (PDCCH) having a RIS radio network temporary identifier (RIS-RNTI) and / or a group common PDCCH (GC-PDCCH) having a RIS-GC-RNTI; indicate a RIS operation mode change or switch; switch the TCI state indicated in the TCI based on a new RIS operation mode TCI that may be indicated, for example, together with a mode indication (e.g., if the RIS mode is not changed, the TCI may not be updated); deactivate one or more TCI states for beamforming information corresponding to an absorption operation (e.g., based on the RIS absorption mode), for example, if the RIS operation mode is the absorption mode; receive a physical downlink shared channel (PDSCH) and / or PDCCH via one or more RIS beams using a new indicated TCI for the downlink (DL) for the new RIS mode; transmit a physical uplink shared channel (PUSCH) and / or physical uplink control channel (PUCCH) via one or more RIS beams using a new indicated TCI for the uplink (UL) for the new RIS mode; and / or receive a PDSCH and / or PDCCH via one or more RIS beams using the DL for an existing TCI, or transmit a PUSCH and / or PUCCH via one or more RIS beams using the UL for an existing TCI for an existing RIS mode, for example, if the RIS mode is not changed.

[0063] The RIS may be turned on or off, or activated or deactivated, for a RIS-assisted system. The WTRU may be configured and / or associated with one or more RISs for a RIS-assisted system.

[0064] The WTRU can measure interference on the primary RS resource for the gNB / transmission and reception point (TRP) in the RIS-assisted system (e.g., perform reference signal measurements associated with the base station and determine the interference level based on the reference signal measurements). The WTRU can measure interference on the secondary RS resource for the associated RIS in the RIS-assisted system (e.g., perform reference signal measurements associated with the RIS and determine the interference level based on the reference signal measurement values). The WTRU can send the interference measurement value (e.g., interference level) to the gNB / TRP. The WTRU can send the recommended RIS operation mode to the gNB / TRP (e.g., can send a message indicating the recommended RIS operation mode to the base station). The WTRU can send the recommended RIS operation mode to the gNB / TRP together with the interference measurement value (e.g., interference level) for the RIS (e.g., the message sent to the base station can indicate the interference level). For example, the recommended RIS operation mode can be based on a first (pre-)configured threshold. For example, the WTRU can determine the interference level based on the reference signal measurement value and determine the recommended RIS operation mode based on the interference level. For example, on the condition that the interference level is greater than a first (pre-)configured threshold (e.g., interference threshold), the recommended RIS operation mode can be the absorption mode. The WTRU can send a recommendation to turn the RIS on or off to the gNB / TRP, and / or can send a recommendation to turn the RIS on or off to the gNB / TRP together with the interference measurement value for the RIS (e.g., the recommendation to turn the RIS on / off can be based on a second (pre-)configured threshold).

[0065] The gNB / TRP can perform, for example, one or more of the following: receive WTRU feedback; determine the RIS to be turned on or off (e.g., based on the WTRU feedback); determine the RIS to be activated or deactivated (e.g., based on the WTRU feedback); determine whether to switch the RIS operation mode and to which mode to switch (e.g., based on the WTRU feedback, where the WTRU feedback may be a recommended RIS operation mode and / or interference measurement, and the WTRU feedback may be carried in PUCCH and / or PUSCH periodically, semi - periodically, and / or aperiodically); and / or indicate the RIS to be turned on / off (e.g., the indication may be carried in GC - PDCCH, MAC CE or RRC signaling, and the container used may depend on the payload size).

[0066] The RIS can perform, for example, one or more of the following: receive configuration information for the RIS - RNTI or RIS - GC - RNTI; receive an instruction from the gNB / TRP to turn the RIS on / off (e.g., via a PDCCH with the RIS - RNTI or a GC - PDCCH with the RIS - GC - RNTI); receive an instruction from the gNB / TRP to activate / deactivate the RIS; receive a GC - PDCCH, for example, when the payload size is small and / or fast on / off is required; receive MAC CE or RRC, for example, when the payload size is large and / or fast on / off is not required; turn the RIS on / off based on the received instruction; and / or activate / deactivate the RIS based on the received instruction.

[0067] The TCI framework may be implemented. Unified TCI may support a (e.g., single) TRP. Non-unified TCI may support the operation of multiple (e.g., up to two) TRP operations (e.g., without supporting coherent joint transmission between TRPs). Non-unified TCI may support the indication of multiple (e.g., up to two) TCI states with a (e.g., one) TCI code point. TCI may support frequency ranges for FR1 and / or FR2.

[0068] Multi-TRP operation can support one or more of the following: dynamic TRP selection, and / or mobility measurements for multi-beam / multi-TRP deployment (e.g., up to 64 synchronization signal blocks (SSBs) per cell), transmission of PDSCH for enhanced mobile broadband (eMBB), multi-TRP diversity for ultra-reliable and low-latency communication (URLLC), multi-TRP operation based on one or more (e.g., two) TRPs, inter-cell multi-TRP operation (e.g., without handover), and / or multi-TRP repetition of PDCCH, PUCCH, and / or PUSCH.

[0069] The channel state information reference signal (CSI-RS) framework may be implemented. CSI interference measurement may be based on zero-power CSI-RS (ZP-CSI-RS) and / or non-zero-power CSI-RS (NZP-CSI-RS) resources. CSI-RS operation may support, for example, a type II codebook for high-resolution CSI feedback, and / or CSI extensions for multi-TRP non-coherent joint transmission (NCJT).

[0070] A reconfigurable intelligent surface (RIS) corresponds to a type of network node that uses a smart radio surface of many small antennas or metamaterial elements that enables control of the propagation environment through adjustable scattering of electromagnetic (EM) waves. The surface can have reflection, refraction, and absorption characteristics that can be reconfigured and adapted to a specific wireless channel environment using a microcontroller (e.g., a field programmable gate array (FPGA)). The configuration of the RIS can be processed or assisted by the network through a (e.g., separate) control signaling link for exchanging (e.g., relevant) side control information.

[0071] The RIS can support the implementation of a smart and reconfigurable wireless environment for a wireless communication system. The RIS may be a plane with several (e.g., a large number of) elements. Each element may induce (e.g., independently) controllable amplitude and / or phase changes to the incident signal. The dense deployment of the RIS in a wireless network can support, for example, the flexible reconfiguration of the wireless channel between a transmitter and a receiver to achieve a desired realization and distribution, which can reduce wireless channel fading and interference and / or improve wireless communication capacity and reliability. The RIS can create virtual line-of-sight (LoS) links (e.g., to bypass obstacles through smart reflection). The RIS can add signal paths in a desired direction, which can improve the channel rank, refine the channel statistics and / or distribution, and / or suppress or nullify interference.

[0072] In contrast to, for example, an active antenna array, a RIS can be integrated into existing wireless systems (e.g., cellular network systems). A RIS can be deployed (e.g., on a large scale) in a wireless network to significantly (e.g., cost-effectively) improve spectral efficiency and energy efficiency. The RIS implementation may change the wireless system / network design, for example, from a multiple-input multiple-output (MIMO) system without RIS to a RIS-assisted MIMO system. A RIS can be deployed more densely in a wireless network at a lower cost than other wireless communication technologies.

[0073] Figure 2 shows an example of a reconfigurable intelligent surface system.

[0074] The RIS-assisted network deployment can be based on use cases and deployment considerations. Exemplary RIS integrated system deployments can include, for example, RIS-based massive MIMO and / or RIS-based coverage extension. In an example of a RIS-based massive MIMO system, the RIS can be deployed (e.g., together) with the gNB / TRP to improve spectral efficiency. In an example of RIS-based coverage extension, the RIS can be deployed away from the gNB / TRP to extend coverage to weak coverage areas and / or coverage holes (e.g., due to obstacles in the line-of-sight link between the gNB / TRP and the WTRU) and / or to extend the coverage area for the gNB / TRP.

[0075] Control information (e.g., including side control information), beamforming related signaling, TCI indication, control information for beamforming and beam management, configuration, quasi-collocation (QCL), etc. may be based on the assumption of a transmitter (Tx) and receiver (Rx) beam pair in which there are no one or more reconfigurable intelligent surface (RIS) nodes. Communication related procedures may be affected in an RIS integrated system. Side control information may enable an (e.g., integrated) RIS to operate efficiently and / or effectively. A mechanism for exchanging control information (e.g., including side control information) may be implemented for an RIS integrated system such as beamforming information, on / off information, UL / DL time domain duplex (TDD) configuration information, TCI configuration, activation, indication, interference management and related signaling, reference signals and related procedures, etc. An RIS may affect control information and signaling implementation and / or TCI operation. UL / DL TDD slots may be configured for an RIS and a WTRU having a link to a gNB via the RIS. A timing advance offset value may be coordinated for a WTRU having a link to a gNB via the RIS, for example, to receive UL signals (e.g., simultaneously) at the gNB and the RIS.

[0076] TCI may be configured and reconfigured for an RIS-based system or an RIS-assisted system. A WTRU may be configured and / or reconfigured in a TCI state, for example, based on the RIS type of the RIS providing service to the WTRU. The RIS providing service to the WTRU can assist the communication link with the WTRU (e.g., an RIS operating in the serving cell of the WTRU). The RIS may be passive, semi-active, hybrid, or active. A passive RIS may refer to an implementation without reflection amplifiers for (e.g., all) unit cells (e.g., or antenna elements). A hybrid or semi-active RIS may correspond to an RIS having one or more unit cells that utilize reflection amplifiers that can provide control in the amplitude response. An active RIS may refer to (e.g., all) unit cells having reflection amplifiers.

[0077] The WTRU may be configured and / or reconfigured in a TCI state based on, for example, the RIS type and / or the RIS operation mode of the RIS providing services to the WTRU. The RIS operation (e.g., regarding the impact on the incident RF signal) may include, for example, one or more of the following (e.g., any combination): reflection, refraction, focusing, collimation, absorption, and / or focusing. The RIS may have different types, different operation modes, different functions, etc. For example, the RIS may be a passive, semi-active, hybrid, or active type of RIS.

[0078] The TCI state may be based on the RIS type and / or the RIS operation mode. The TCI state may be for one RS resource (e.g., corresponding to one beam) or multiple RS resources (e.g., corresponding to multiple beams). The RS resource may be a resource for CSI-RS, TRS, SSB, etc. For example, the RIS may be capable of reflecting multiple beams simultaneously. The RIS may be made from an (e.g., large) array of passive scattering elements that may be called unit cells. Each unit cell may be configured (e.g., by the network) to achieve one or more of desired signal reflection, refraction, focusing, collimation, absorption, etc.

[0079] The TCI state may be configured or reconfigured (or activated or deactivated) for different RIS operation modes (e.g., the configuration information may indicate the respective association between the TCI state and the RIS operation mode). The RIS operation mode may include, for example, a reflecting RIS, a transmitting RIS, a receiving RIS, a RIS that transmits and reflects simultaneously, a RIS that reflects and detects simultaneously, an amplifying RIS, etc. For example, a RIS that transmits and reflects simultaneously (e.g., the operation mode) may enable a reconfigurable radio environment with 360-degree coverage. A RIS that reflects and detects simultaneously may reflect the incident signal simultaneously (e.g., in a programmable manner), and the incident signal may be supplied to the detection unit (e.g., together, simultaneously, in parallel).

[0080] CSI-RS resources can be associated with the RIS. The CSI-RS resources can be configured and / or used to reflect beams at the RIS. The CSI-RS resources associated with the RIS can be used to transmit beams at the RIS (e.g., when the RIS is capable of transmitting beams). The CSI-RS resources associated with the RIS can be used to simultaneously transmit and reflect beams at the RIS (e.g., when the RIS is capable of simultaneously reflecting and transmitting beams). There can be multiple (e.g., two) beams resulting from a single beam (e.g., between the gNB and the RIS). The resulting beams may be referred to as reflected beams and transmitted beams (e.g., between the RIS and the WTRU). A first WTRU can measure the CSI-RS and report a beam (e.g., layer 1 reference signal received power (L1-RSRP) for the CSI-RS resource). A second WTRU can (e.g., further) measure the same CSI-RS and report the same beam. The gNB can configure the WTRU with the same TCI state. The gNB can activate the TCI state (e.g., when necessary). The gNB can indicate the TCI state for the WTRU to receive the PDSCH, e.g., when the gNB transmits data to the WTRU. The gNB can transmit data to another (e.g., second) WTRU (e.g., further). The gNB can indicate the TCI state for the other (e.g., second) WTRU to receive the PDSCH (e.g., further). The gNB can allocate different frequency resources to different WTRUs to receive the PDSCH using the same TCI state for the reflected beam and the transmitted beam.

[0081] (For example, a first) WTRU can measure (for example, a first) CSI-RS and report (for example, a first) beam, while another (for example, a second) WTRU can measure a different (for example, a second) CSI-RS and report another (for example, a second) beam. The gNB can configure (for example, first and second) WTRUs having different TCI states. The gNB can activate different TCI states (for example, when necessary). The gNB can indicate, for example, a (for example, first) TCI state for a (for example, first) WTRU to receive a PDSCH when the gNB transmits data to the (for example, first) WTRU. The gNB can transmit (for example, further) data to another (for example, a second) WTRU. The gNB can indicate another (for example, a second) TCI state for the other (for example, a second) WTRU to receive (for example, further) PDSCH. The gNB can allocate different frequency resources to (for example, first and second) WTRUs to receive PDSCH using different TCI states for reflected and transmitted beams.

[0082] The CSI-RS resources associated with the gNB may not be used for the RIS. The TCI state associated with the RIS (for example, operating in absorption mode) may not be configured for the WTRU (for example, because the beam may not be received by the WTRU). The CSI-RS resources associated with the RIS may be used for the RIS, and the RIS may operate in a simultaneous reflection and sensing mode. The TCI state may be associated with the RIS and / or configured for the WTRU, for example, according to the RIS operating mode.

[0083] FIG. 3 shows an example of a RIS configured as a reflective RIS based on a RIS operating mode for beam reflection only. The WTRU can be configured with a TCI state associated with the gNB. The WTRU can be configured with an additional TCI state associated with the RIS for an operation / operating mode (for example, beam reflection only).

[0084] Figure 4 shows an example of a RIS configured as a reflecting and transmitting RIS based on the RIS operation mode for simultaneous reflection and transmission. The WTRU may be configured in a TCI state associated with the gNB. The WTRU may be configured in a TCI state associated with the RIS for the operation mode having a reflection beam. The WTRU may be (e.g., further) configured in an (e.g., additional) TCI state associated with the RIS for the operation mode of transmitting a beam if, for example, the RIS is capable of transmitting a beam (e.g., configured therefor).

[0085] The CSI-RS resource set may be configured for the RIS. The beam may be repeated, for example, for the CSI-RS resources within the CSI-RS resource set, for the link between the gNB / TRP and the RIS (e.g., the gNB-RIS link). The beam repetition may be indicated to the RIS such that, for example, the RIS recognizes that the same beam is repeated on the CSI-RS resources within the CSI-RS resource set for the link between the gNB / TRP and the RIS. The beam repetition and / or the repetition indication may be used for beam management or beam sweeping for the RIS-assisted system. To manage the beam for the link between the gNB / TRP and the RIS, a repetition indicator for the CSI-RS resources may be sent to the RIS. The beam may or may not be repeated for the link between the RIS and the WTRU (e.g., the RIS-WTRU link). The beam sweeping may be performed (e.g., alternatively) for the link between the RIS and the WTRU. The RIS and the WTRU may be configured, for example, to use the same CSI-RS resource set for the reflection beam and the transmission beam if the reflection beam and the transmission beam are combined. The RIS may reflect the same beam in different directions. The RIS may be able to transmit the same beam in different directions simultaneously. Different beams may be reflected and transmitted via the CSI-RS resources within the same CSI-RS resource set for the RIS-WTRU link.

[0086] Different CSI-RS resource sets for the reflected beam and the transmitted beam can be configured for the RIS and the WTRU, for example, if the reflected beam and the transmitted beam are not combined. The same beam can be repeated via the CSI-RS resources within the CSI-RS resource set for the gNB-RIS link. Different beams can be reflected and transmitted via the CSI-RS resources within different CSI-RS resource sets for the RIS-WTRU link.

[0087] Figure 5 shows an example of a TCI configuration for an RIS configured for simultaneous reflection and transmission. As shown by the example of Figure 5, the WTRU can be configured in a primary TCI state associated with the gNB / TRP. The WTRU can be configured in a (e.g., additional / secondary) TCI state associated with the RIS. For example, the WTRU can be configured in an additional / secondary TCI state associated with the RIS that performs beam reflection (e.g., if the RIS is operating in reflection mode). The WTRU can be configured in an additional / secondary TCI state associated with the RIS that performs beam transmission (e.g., if the RIS is operating in transmission mode).

[0088] The association between the RIS type and the RIS operation mode can be utilized, for example, by the gNB / TRP. Information for the association between the RIS type and the RIS operation mode can be indicated to the WTRU. Some RIS operation modes may be possible (e.g., available) for some RIS types, but may not be possible (e.g., not available) for other RIS types. For example, a RIS operation mode with a reflective RIS can be used as a passive RIS. For example, a RIS operation mode with an amplified RIS (e.g., for the entire RIS) may be used as an active RIS, a semi-active RIS, or a hybrid RIS. Different RIS operation modes can be associated with the same or different RIS types. Different RIS types may be associated with the same or different RIS operation modes. Some RIS operation modes may be associated with some RIS types, and other RIS operation modes may be associated with other RIS types.

[0089] Figure 6 shows an exemplary method for a hybrid RIS TCI configuration for the RIS type and the RIS operation mode. As shown in Figure 6, the WTRU can be configured in a TCI state, for example, based on the number of RISs. For example, the WTRU can be configured in the TCI state of M RISs. The M RISs can have the same or different types. The WTRU can be configured in the TCI state of each (e.g., each) RIS type. For example, the WTRU is L for each type i iIt can be configured in a TCI state. The RIS operating mode can be determined by the gNB, for example, based on the RIS type. The WTRU can receive an indication of the RIS type and / or the RIS mode. The WTRU can be configured or reconfigured for the TCI state, for example, according to the RIS mode. The WTRU can be configured in a TCI state for the RIS reflection mode. The WTRU can be configured in a TCI state for the RIS refraction mode. The WTRU can select a TCI state subset, for example, based on the indicated RIS type / mode. The WTRU can select a TCI state subset based on the indicated RIS mode, for example, if the RIS absorption mode is determined, indicated, or known.

[0090] Figure 7 shows an exemplary method of a hybrid RIS for multi-RIS with RIS mode switching and TCI reconfiguration. As shown in Figure 7, the WTRU can be configured in a TCI state associated with one or more (e.g., several) RISs. Different RISs can have different types and / or different operating modes. For example, the WTRU can be configured in different TCI states associated with each RIS of different types and / or modes. The RIS mode can be determined by the gNB, for example, based on the feedback of the WTRU. The feedback of the WTRU can trigger an RIS mode switch. The feedback of the WTRU can include, for example, one or more of WTRU measurements (e.g., reference signal measurements and / or interference measurements / levels), WTRU recommended RIS operating mode, WTRU measured interference level, etc. The RIS can switch to a different RIS mode (e.g., RIS reflection, refraction, or absorption mode), for example, if the feedback of the WTRU triggers an RIS mode switch. The mode switch can depend on the RIS mode determined (e.g., based on the feedback of the WTRU). The WTRU can receive an indication of the switched or changed RIS mode. The WTRU can be reconfigured in a TCI state based on the determined and changed RIS mode.

[0091] The RIS operation mode may be indicated, for example, by PDCCH, group common PDCCH (GC-PDCCH), MAC CE, RRC signaling, etc. (For example, each) RIS may be configured with an RNTI (for example, RIS-RNTI). The same or different RNTIs (for example, further RIS-RNTI) may be configured for different RISs. The PDCCH may be masked with an RIS-RNTI, for example, when the PDCCH is used. The RIS can decode the PDCCH using, for example, its own RNTI of the RIS (for example, RIS-RNTI). The RIS may obtain downlink control information (DCI) in the PDCCH for the RIS operation mode indicator, for example, when passing the CRC test. The RIS operation mode may be updated, changed, or switched (for example, individually). Table 1 shows exemplary RIS operation mode indicators. As shown in Table 1, four RIS operation modes (for example, reflection, refraction, absorption, and transmission) may exist.

[0092] For example, when GC-PDCCH is used, a RIS-based group common RNTI may be used. The group common RNTI may be configured for the RIS. The RIS can decode the GC-PDCCH using, for example, the group common RNTI for the RIS (for example, RIS-GC-RNTI). The RIS can obtain the DCI within the GC-PDCCH for the RIS operation mode indicator, for example, when passing the CRC test. The RISs within a group (for example, all RISs) can update, change, or switch their operation modes (for example, simultaneously).

[0093]

Table 1

[0094] CSI-RS resources can be configured for a WTRU for, e.g., a gNB (e.g., a gNB only), a RIS (e.g., a RIS only), both a gNB and a RIS, etc. The WTRU can be configured using a CSI-RS resource set for a beam from the gNB to the WTRU. The WTRU can be configured with an additional CSI-RS resource set for a beam from the RIS to the WTRU. The CSI-RS resources may not be associated with the RIS, e.g., when the WTRU is configured with a CSI-RS resource set for a beam from the gNB to the WTRU. The CSI-RS resources may not be associated with the gNB, e.g., when the WTRU is configured with an additional CSI-RS resource set for a beam from the RIS to the WTRU. The CSI-RS resources can be associated with a RIS (e.g., a RIS only). One implementation may use a RIS-only CSI-RS resource or resource set. One implementation may use a gNB-only CSI-RS resource or resource set. The WTRU may operate (e.g., be operable) in an environment of a gNB with RIS deployment, e.g., by splitting CSI-RS resources into a RIS-only CSI-RS resource and a gNB-only CSI-RS resource. The WTRU can measure beam quality for the gNB / TRP and / or the RIS, e.g., based on L1-RSRP, L1-SINR, etc., using a gNB / TRP-only CSI-RS resource and / or a RIS-only CSI-RS resource. The WTRU can report a CSI-RS resource indicator (CRI) to the gNB / TRP. The WTRU can be configured with CSI-RS resources separately for the gNB / TRP and the RIS, and / or together for the gNB / TRP and the RIS. The TCI state can be associated with the gNB / TRP and / or the RIS.

[0095] The WTRU can be configured in a TCI state associated with a gNB (e.g., the gNB only) to receive, for example, the PDSCH from the gNB. The WTRU can be configured in an additional TCI state associated with a RIS (e.g., the RIS only). The TCI state associated with the gNB (e.g., the gNB only) can provide beamforming information for the WTRU to receive the PDSCH from the gNB. The TCI state associated with the RIS (e.g., the RIS only) can provide beamforming information for the WTRU to receive the PDSCH from the RIS.

[0096] The WTRU can be configured in a TCI state associated with a gNB (e.g., the gNB only) to receive, for example, the PDCCH from the gNB. The WTRU can be configured in an additional TCI state associated with a RIS (e.g., the RIS only). The TCI state associated with the gNB (e.g., the gNB only) can provide beamforming information for the WTRU to receive the PDCCH from the gNB. The TCI state associated with the RIS (e.g., the RIS only) can provide beamforming information for the WTRU to receive the PDCCH from the RIS.

[0097] The WTRU can be configured in a TCI state associated with a gNB (e.g., the gNB only) to transmit, for example, the PUSCH to the gNB. The WTRU can be configured in an additional TCI state associated with a RIS (e.g., the RIS only). The TCI state associated with the gNB (e.g., the gNB only) can provide beamforming information for the WTRU to transmit the PUSCH to the gNB. The TCI state associated with the RIS (e.g., the RIS only) can provide beamforming information for the WTRU to transmit the PUSCH to the RIS.

[0098] Similarly, to transmit PUCCH, the WTRU can be configured with a TCI state associated with the gNB (e.g., the gNB only). The WTRU can be configured with an additional TCI state associated with the RIS (e.g., the RIS only). The TCI state associated with the gNB (e.g., the gNB only) can provide beamforming information for the WTRU to transmit PUCCH to the gNB. The TCI state associated with the RIS (e.g., the RIS only) can provide beamforming information for the WTRU to transmit PUCCH to the RIS.

[0099] The TCI can be activated and deactivated for the RIS support system. The TCI can be activated or deactivated based on the RIS operating mode and / or the RIS type. The TCI activation and deactivation can be implemented for a RIS support system having one or more deployed RISs. The network (NW) can configure and / or reconfigure the RIS. The RIS may or may not be activated before activating the TCI state. The WTRU can monitor RS resources (e.g., CSI-RS resources associated with the RIS), for example, when the RIS is activated. The WTRU can measure signals reflected or transmitted from the RIS. The WTRU can monitor RS resources (e.g., CSI-RS resources associated with the RIS), for example, when the RIS is not activated. The WTRU may not measure signals for an inactive RIS, for example, because an inactive RIS may not reflect or transmit signals. The NW can activate or deactivate (e.g., configure) the RIS, for example, based on need. The WTRU may or may not be configured with TCI states for each activated RIS. The WTRU can report the most relevant RIS (e.g., the best M RISs) having a beam quality that exceeds a (preconfigured) threshold. The beam quality can be measured via the corresponding RS (e.g., CSI-RS) resources using, for example, one or more metrics (e.g., L1-RSRP, L1-SINR, etc.). The WTRU can report the RIS ID of the most relevant RIS based on one or more measurements. The WTRU can report the RIS ID via UL signaling or a channel (e.g., PUCCH, PUSCH, MAC CE, etc.). In some examples, the best beam quality can be the strongest beam RIS or the largest number of beams having a moderately good quality that is not necessarily the strongest beam. The NW can associate the WTRU with one or more RISs, for example, based on a report from the WTRU.

[0100] Figure 8 shows an exemplary method for TCI activation and deactivation for a RIS. As shown in Figure 8, the gNB / TRP can activate the RIS. A WTRU can be associated with the RIS. The WTRU can be configured in a TCI state for the associated RIS. The WTRU can report measurement values. The TCI state can be activated for the WTRU. One or more TCI states can be indicated among the activated TCI states.

[0101] Figure 9 shows an exemplary method for RIS operation for a RIS-based or RIS-assisted system. As shown in Figure 9, the gNB / TRP can turn on or activate one or more (e.g., a set or group or all) RISs deployed within the cell. The WTRU can perform measurements and send reports to the gNB / TRP. The gNB / TRP can configure the RIS, for example, using the RIS operation mode and / or operation parameters. The WTRU can perform measurements and reports. One or more (e.g., some) RISs can be deactivated, for example, based on measurements and reports from the WTRU. The TCI state can be deactivated for the deactivated RIS. For example, the TCI state can be automatically deactivated when the RIS is deactivated. In some examples, the TCI state can be deactivated separately from the RIS deactivation.

[0102] Figure 10 shows an exemplary method for TCI activation and deactivation for a RIS support system. As shown in Figure 10, a WTRU can communicate with a particular type of RIS (e.g., the WTRU can transmit to or receive from a particular type of RIS). The gNB can determine the RIS operating mode based on the RIS type. The TCI state can be activated or deactivated for the WTRU, e.g., according to the RIS operating mode. The WTRU can be involved in autonomous WTRU activation / deactivation. The WTRU can, for example, activate or deactivate the TCI state based on the indicated RIS operating mode. The TCI state can be activated for the WTRU, e.g., if the determined RIS operating mode is the RIS reflection mode. The TCI state can be activated for the WTRU, e.g., if the determined RIS operating mode is the RIS refraction mode. The TCI state can be deactivated for the WTRU, e.g., if the determined RIS operating mode is the RIS absorption mode.

[0103] The TCI state for the WTRU can be activated for each (e.g., associated) active RIS associated with the WTRU. In some examples, there can be multiple activated TCI states. For example, if there is no RIS associated with the WTRU, a certain (e.g., determined, selected, (pre-)configured, indicated) number of TCI states (e.g., 8 TCI states) can be activated. For example, if one (e.g., an) active RIS is associated with the WTRU, a larger number of TCI states (e.g., 16 TCI states) can be activated. For example, if multiple (e.g., two) active RISs are associated with the WTRU, a larger number of TCI states (e.g., 24 TCI states) can be activated. The number of activated RIS states can increase as the number of associated activated TCIs increases.

[0104] A large payload may be used in the MAC CE for control (e.g., if non-uniform TCI is used) for a number of activated TCI states. The MAC CE payload may be used, for example, to activate a TCI state for a control channel such as a PDCCH or PUCCH. An increase in the payload size for TCI activation may result in higher overhead in the DCI for TCI indication (e.g., also).

[0105] In some examples, there may be no RIS associated with the WTRU (e.g., within a cell). In some examples, a larger number of TCI states may be configured (e.g., up to 64 configured TCI states). For example, if one (e.g., an) active RIS is associated with the WTRU, a larger number of TCI states may be configured (e.g., up to 128 configured TCI states). For example, if multiple (e.g., two) active RISs are associated with the WTRU, a larger number of TCI states may be configured (e.g., up to 192 configured TCI states). The number of configured RIS states may increase as the number of associated activated TCIs increases.

[0106] TCI indications and / or updates may be provided for RIS-based systems and RIS assistance systems. The WTRU may receive PDSCH from the gNB and / or the RIS (e.g., in an RIS assistance system). The TCI state may be indicated to the WTRU to receive PDSCH from the gNB, for example, when the beam quality from the gNB (e.g., based on L1-RSRP, L1-SINR) exceeds a preconfigured threshold. The TCI state may be further indicated to the WTRU to receive PDSCH from the RIS, for example, when the beam quality from the gNB is below a preconfigured threshold, or when the beam from the gNB is blocked and the beam quality from the RIS exceeds a preconfigured threshold. The TCI state may be indicated to the WTRU to receive PDSCH from the gNB and the RIS, for example, when the beam quality from the gNB and the RIS exceeds a preconfigured threshold (e.g., to achieve a diversity gain for PDSCH). The TCI state may be indicated to the WTRU via DCI carried in the PDCCH. The beam quality can be based on L1-RSRP, L1-SINR, etc.

[0107] The WTRU may transmit PUSCH to the gNB and / or the RIS. The TCI state may be indicated to the WTRU to transmit PUSCH to the gNB, for example, when the beam quality for the gNB exceeds a preconfigured threshold. The TCI state may be further indicated to the WTRU to transmit PUSCH to the RIS, for example, when the beam quality for the gNB is below a preconfigured threshold, or when the beam to the gNB is blocked and the beam quality for the RIS exceeds a preconfigured threshold. The TCI state may be indicated to the WTRU to transmit PUSCH to the gNB and the RIS, for example, when the beam quality for the gNB and the RIS exceeds a preconfigured threshold (e.g., to achieve a diversity gain for PUSCH). The TCI state may be indicated to the WTRU via DCI carried in the PDCCH.

[0108] The WTRU may (e.g., be able to) receive PDCCH from the gNB and / or the RIS. The TCI state may be indicated to the WTRU (e.g., via MAC CE). The TCI state may be indicated to the WTRU to receive PDCCH from the gNB, for example, when the beam quality from the gNB exceeds a (pre-)configured threshold. The TCI state may be further indicated to the WTRU to receive PDCCH from the RIS, for example, when the beam quality from the gNB is below a (pre-)configured threshold, or when the beam from the gNB is blocked and the beam quality from the RIS exceeds a (pre-)configured threshold. The TCI state may be indicated to the WTRU to receive PDCCH from the gNB and the RIS, for example, to achieve a diversity gain for the PDCCH, when the beam qualities from the gNB and the RIS exceed a (pre-)configured threshold.

[0109] The WTRU may (e.g., be able to) transmit PUCCH to the gNB and / or the RIS. The TCI state may be indicated to the WTRU (e.g., via MAC CE). The TCI state may be indicated to the WTRU to transmit PUCCH to the gNB, for example, when the beam quality for the gNB exceeds a (pre-)configured threshold. The TCI state may be further indicated to the WTRU to transmit PUCCH to the RIS, for example, when the beam quality for the gNB is below a (pre-)configured threshold, or when the beam to the gNB is blocked and the beam quality for the RIS exceeds a (pre-)configured threshold. The TCI state may be indicated to the WTRU to transmit PUCCH to the gNB and the RIS, for example, to achieve a diversity gain for the PUCCH, when the beam qualities for the gNB and the RIS exceed a (pre-)configured threshold.

[0110] The WTRU can indicate to the gNB / TRP a TCI state among the activated TCI states for the RIS (e.g., based on WTRU measurements) in order to receive the PDSCH from the RIS. The WTRU can indicate to the gNB / TRP a TCI state among the activated TCI states for the RIS (e.g., based on WTRU measurements) in order to receive the PDCCH or other DL signals or channels from the RIS, or to transmit the PUCCH, PUSCH, sounding reference signal (SRS), or other UL signals or channels. The WTRU can indicate the TCI state to the gNB / TRP, for example, using the PUCCH, PUSCH, MAC CE, etc.

[0111] Figure 11 shows an exemplary method for indicating and updating TCI for a RIS-assisted system. As shown in Figure 11, the WTRU can receive an indication of a TCI state associated with the gNB. The WTRU can receive an indication of a TCI state associated with the gNB, for example, when the beam quality exceeds a (preconfigured) threshold. The WTRU can receive an indication of a TCI state associated with the RIS, for example, when the beam quality is below a (preconfigured) threshold. The WTRU can receive an indication of a TCI state associated with the RIS, for example, when the beam quality exceeds a (preconfigured) threshold. The WTRU can receive an indication of a TCI state associated with another RIS, for example, when the beam quality is below a (preconfigured) threshold. The WTRU can use the reference signal (beam) corresponding to the indicated TCI state to receive the PDSCH in the RIS-assisted system.

[0112] Figure 12 shows an exemplary method for TCI indication and update for a RIS support system. As shown in Figure 12, a WTRU can receive an indication of a TCI state associated with a gNB / TRP. The WTRU can receive an indication of a TCI state associated with a gNB / TRP, for example, when the beam quality exceeds a threshold. The WTRU can receive an indication of a TCI state associated with a RIS, for example, when the beam quality is below a threshold for the gNB / TRP. The WTRU can receive an indication of a TCI state associated with a RIS, for example, when the beam quality exceeds a threshold of the RIS. The WTRU can receive an indication of a TCI state associated with another RIS, for example, when the beam quality is below a threshold of the RIS.

[0113] The WTRU can receive different indications, for example, according to control or data. For example, the WTRU can receive an indication of TCI (for example, for data) via DCI for a RIS support system. The WTRU can receive an indication of TCI (for example, for control) via MAC CE for a RIS support system. The WTRU can perform transmission or reception (for example, according to downlink or uplink respectively) for a RIS support system. The WTRU can perform PDCCH or PDSCH reception (for example, for downlink) using the beam indicated in the TCI state for a RIS support system. The WTRU can perform PUCCH or PUSCH transmission (for example, for uplink) using the beam indicated in the TCI state for a RIS support system.

[0114] The TCI state can be based on, for example, the reflection beam and the transmission beam for an RIS that performs simultaneous reflection and transmission. In one example, there can be four beams for reflection and another four beams for transmission. The TCI state can be defined together, for example, when the reflection beam and the transmission beam are combined. Table 2 shows an example of the TCI state for the combined reflection beam and transmission beam. The TCI state can be defined for, for example, the reflection beam and the transmission beam when the reflection beam and the transmission beam are not combined (e.g., additionally). Table 3 shows an example of the TCI state for the separated reflection beam and transmission beam.

[0115]

Table 2

[0116]

Table 3

[0117] The TCI state can be defined for the reflection beam and the transmission beam (e.g., separately). Table 4 shows an example of the TCI state for the reflection beam. Table 5 shows an example of the TCI state for the transmission beam. The TCI code point can be defined for (e.g., each) TCI state and / or joint TCI state. Table 6 shows an example of the TCI code point for the joint TCI state of the reflection beam and the transmission beam.

[0118] Beam sweeping and beam management can be supported (e.g., implemented) for multiple / different RIS operating modes and for DL and UL transmission and / or reception using the RIS in an RIS-assisted system.

[0119]

Table 4

[0120]

Table 5

[0121]

Table 6

[0122] Figure 13 shows an exemplary method for TCI indication and update for a RIS-assisted system (e.g., involving simultaneous reflection and transmission). The WTRU can receive an indication of the TCI state of a reflection beam associated with the RIS. The WTRU can receive an indication of the TCI state of another reflection beam associated with the same or a different RIS, for example, when the beam quality (e.g., with respect to a source reference signal) falls below a (pre-)configured threshold. The WTRU can receive an indication of the TCI state of a transmission beam associated with the same or a different RIS, for example, when the beam quality falls below a (pre-)configured threshold. The WTRU can use the beam corresponding to the indicated TCI state for the reflection beam and / or the transmission beam, for example, for receiving the PDSCH or PDCCH, for transmitting the PUSCH or PUCCH, etc. The beam quality can be based on the measurement of a source reference signal.

[0123] A large payload can be used in MAC CE for control (e.g., control information or control signaling). For example, when non-uniform TCI is used (e.g., only in that case, for a large number of configured or activated TCI states), a large payload can be used in MAC CE for control signaling. A large payload can be used in MAC CE for control signaling and / or data, for example, when uniform TCI is used. A large payload can be used in DCI for data. For example, a large payload can be used in DCI for data when non-uniform TCI is used (e.g., only in that case). A large payload can be used in DCI for control signaling and / or data, for example, when uniform TCI is used. A large payload can be used for the TCI state for control signaling such as PDCCH reception or PUCCH transmission for a RIS-assisted system. A large payload can be used for the TCI state for data such as PDSCH reception or PUSCH transmission for a RIS-assisted system.

[0124] FIG. 14 shows an exemplary method for PDSCH reception in a WTRU for RIS type and RIS mode based on the feedback of the WTRU. As shown in FIG. 14, the WTRU can communicate with a certain (e.g., determined, selected, indicated) type of RIS. The WTRU can recommend an RIS mode (e.g., of operation). The gNB can determine the RIS mode based on the feedback of the WTRU. The gNB can determine and indicate an RIS mode different from the recommended RIS mode. For example, if the recommended RIS mode is the reflection mode, beam reflection may be performed at the RIS. The WTRU can receive the PDSCH using the reflected beam from the RIS. Beam refraction may be performed at the RIS, for example, if the recommended RIS mode is the refraction mode. The WTRU can receive the PDSCH using the refracted beam from the RIS. Beam absorption may be performed at the RIS, for example, if the recommended RIS mode is the absorption mode. The WTRU can remove the interference beam, for example, when / receiving the PDSCH.

[0125] FIG. 15 shows an exemplary method for RIS mode switching and TCI indication. As shown in FIG. 15, a WTRU may perform PDCCH / PDSCH reception and / or PUCCH / PUSCH transmission via an RIS for an RIS-assisted system based on the RIS type and / or the RIS operation mode. The WTRU may be configured using RS resources, for example, according to the RIS type and / or the RIS operation mode.The WTRU can perform, for example, one or more of the following: receive configuration information having an association with a TCI state and / or, for example, a RIS type and / or a RIS operation mode; activate a TCI state for beamforming information in a RIS-assisted system (e.g., based on the RIS operation mode); receive a TCI indication regarding beam information for reception or transmission via the RIS; decode a PDCCH having a RIS-RNTI or a GC-PDCCH having a RIS-GC-RNTI; receive an indication to change or switch the RIS operation mode; switch the TCI state based on a newly indicated TCI for a new RIS operation mode (e.g., the TCI may be indicated by a mode indication via a PDCCH, a GC-PDCCH, etc., and / or if the RIS mode is not changed, the TCI may not be indicated or updated); deactivate one or more TCI states for beamforming information corresponding to an absorption operation based on a RIS absorption mode (e.g., deactivate TCI states associated with other RIS operation modes on the condition that the RIS operation mode is the absorption mode); receive a PDCCH and / or a PDSCH via one or more RIS beams using a newly indicated DL TCI associated with a new RIS mode; transmit a PUCCH and / or a PUSCH via one or more RIS beams using a newly indicated UL TCI associated with a new RIS mode; receive a PDCCH and / or a PDSCH via one or more RIS beams using an existing DL TCI, for example, if the RIS mode is not changed; and / or transmit a PUCCH and / or a PUSCH via one or more RIS beams using an existing UL TCI for an existing RIS mode, for example, if the RIS mode is not changed.

[0126] RIS on / off information can be provided for efficient interference management for RIS-based systems or RIS-assisted systems. The RIS can be turned on (e.g., activated for operation) or off (e.g., deactivated for operation), for example, by using group common PDCCH (GC-PDCCH) to control when the RIS is on and off. The on / off information can be indicated using the same RNTI and different PDCCH monitoring periods or windows for the GC-PDCCH. Different RNTIs can be used with the same PDCCH monitoring period and window. The RIS can be divided into multiple groups. The RIS on / off information may be applied to different RIS groups. A bitmap for the on / off information can be used for each RIS group. For example, different bitmap sizes can be used depending on the group size.

[0127] A RIS (e.g., or a RIS controller) can decode the GC-PDCCH and / or read the DCI carried in the GC-PDCCH. The WTRU can obtain a control field (e.g., a bitmap), which can indicate the (e.g., each) RIS state (e.g., whether the RIS is on or off) within the group. The gNB can configure a RIS group ID. The gNB can configure a RIS ID for each (e.g., individual) RIS in each (e.g., respective) RIS group. The RIS group ID may be masked by the GC-PDCCH. The RIS can decode the GC-PDCCH based on, for example, a CRC masked by the RIS group ID. The RIS may read the RIS ID and / or the associated on / off indicator, for example, when the RIS obtains the control field of the RIS on / off indicator within the DCI. For example, if the RIS on / off indicator indicates RIS "on", the RIS can be turned on. For example, if the RIS on / off indicator indicates RIS "off", the RIS can be turned off. PDCCH monitoring may be supported during the off period, for example, to decode and read the RIS on / off indicator during the RIS off period.

[0128] The MAC CE can be used, for example, to support a larger number of RISs. The GC-PDCCH may not be efficient, for example, when the payload size is large. The MAC CE can be used to carry the RIS on / off indicator. The MAC CE may be triggered to indicate the RIS on / off state, for example, when the RIS group size is larger than a (pre-)configured threshold. The GC-PDCCH can be triggered to indicate the RIS on / off state, for example, when the RIS group size is not larger than a (pre-)configured threshold.

[0129] RRC signaling may be used for slow changes of the RIS on / off state. GC-PDCCH can be used, for example, based on interference conditions. For example, when the interference conditions change rapidly, GC-PDCCH can be used. For example, when the interference conditions change slowly, RRC signaling can be used. MAC CE can be used, for example, to balance the payload size and the speed of RIS control. The RIS / RIS controller can act (e.g., behave) as a WTRU in the control signaling protocol / procedure.

[0130] Figure 16 shows an exemplary method of RIS on / off information for efficient interference management. As shown in Figure 16, the RIS may be configured using the GC-PDCCH monitoring period. The RIS can read the RIS ID in the DCI carried within the GC-PDCCH. The RIS can continue to read the RIS on / off indicator in the DCI, for example, when the decoded RIS ID matches the RIS ID of the RIS itself. When the RIS indicator is "on", the RIS can be turned on. When the RIS indicator is "off", the RIS can be turned off. The RIS may stop reading the RIS on / off indicator in the DCI, for example, when the decoded RIS ID does not match the RIS ID of the RIS itself. The RIS may ignore the RIS on / off indicator and / or discard the control information (e.g., when the decoded RIS ID does not match the RIS ID of the RIS itself).

[0131] Figure 17 shows an exemplary method of RIS on / off indication via group RNTI. As shown in Figure 17, the RIS can be configured using the group RNTI and the GC-PDCCH monitoring period. The RIS can decode the GC-PDCCH masked with the group RNTI during the (configured) monitoring period. The RIS can, for example, decode the GC-PDCCH (successfully) if the group RNTI matches. The RIS can read the RIS ID of the group within the DCI carried in the GC-PDCCH. The RIS can, for example, continue to read the RIS on / off indicator in the DCI if the decoded RIS ID matches the RIS ID of the RIS itself within the group. If the RIS indicator is "on", the RIS can be turned on. If the RIS indicator is "off", the RIS can be turned off. The RIS may, for example, stop reading the RIS on / off indicator in the DCI if the decoded RIS ID does not match the RIS ID of the RIS itself within the group. The RIS may ignore the RIS on / off indicator and / or discard the control information (e.g., if the decoded RIS ID does not match the RIS ID of the RIS itself).

[0132] On / off pattern signaling may (e.g., further) be used. The RIS may be on during certain symbols or slots, etc., which may be valid, for example, for a certain period or until the next indication and / or reconfiguration.

[0133] The NW can turn on the RIS (e.g., set the RIS to the on mode) based on the interference measurement value. For example, the NW can turn on the RIS based on an interference measurement report from the WTRU. The WTRU can report the interference measurement value and an indication of the RIS contributing to the interference. The WTRU can report one or more interfering RISs to the NW. The WTRU can report an RIS as an interfering RIS, for example, when the interference level is high (e.g., when the interference exceeds a (pre-)configured threshold). The WTRU can recommend, for example, whether to turn the RIS on or off based on the interference measurement value. The RIS can be turned off, for example, based on the interference level (e.g., when the interference exceeds a (pre-)configured threshold). For example, when the interference is below a (pre-)configured threshold, the RIS can be turned on (e.g., remain on).

[0134] The RIS operation mode can be switched or changed, for example, based on the interference measurement value (e.g., as described with respect to FIG. 18). For example, the RIS operation mode can be switched or changed based on an interference measurement report from one or more WTRUs (e.g., a report indicating the interference level associated with the RIS and / or the interference level associated with the gNB). The WTRU can, for example, perform one or more of the following: measure the interference to the primary RS resource for the gNB / transmission and reception point (TRP) in the RIS-assisted system; measure the interference on the secondary RS resource for the associated RIS in the RIS-assisted system. For example, when the interference level resulting from the RIS is high (e.g., the beam quality exceeds a threshold), the RIS operation mode can be switched or changed from the reflection mode to the absorption mode. For example, when the interference level resulting from the RIS is low (e.g., the beam quality is below a threshold), the RIS operation mode can be switched or changed to the reflection mode or the transmission mode. The beam quality can be measured, for example, by L1-RSRP, L1-SINR, etc.

[0135] Figure 18 shows an exemplary method for RIS mode switching and TCI indication based on interference level. As shown in Figure 18, the WTRU may receive configuration information having an association with the RIS based on, for example, the TCI state and / or the RIS type and / or the RIS operation mode. The WTRU may perform measurements (e.g., reference signal measurements and / or interference measurements) and report / recommend the RIS operation mode (e.g., to a network node, e.g., a gNB). The WTRU can determine (e.g., based on measurements) whether the interference level exceeds a (pre-)configured threshold (e.g., an interference threshold). If the interference level exceeds the threshold (e.g., is greater than the threshold), the WTRU can feedback (e.g., report / recommend) an absorption mode (e.g., the RIS absorption mode). If the interference does not exceed the threshold (e.g., is below the threshold or less than the threshold), the WTRU can feedback (e.g., report / recommend) one or more other modes (e.g., other than the absorption mode). The WTRU may decode a PDCCH having an RIS-RNTI or a GC-PDCCH having an RIS-GC-RNTI. The WTRU may receive an instruction to change or switch the RIS operation mode. If the WTRU receives an instruction to switch the RIS operation mode, the WTRU may switch the TCI state (activate / deactivate one or more TCI states) based on the TCI indicated for the new RIS operation mode (e.g., the TCI may be indicated by a mode instruction via a PDCCH, a GC-PDCCH, etc., and / or if the RIS mode is not changed, the TCI may not be indicated or may not be updated). If the indicated TCI state corresponds to the RIS absorption mode, the WTRU can deactivate one or more TCI states for beamforming information. The WTRU can receive the PDCCH and / or the PDSCH via one or more RIS beams using the newly indicated DL TCI associated with the new RIS mode. The WTRU can transmit the PUCCH and / or the PUSCH via one or more RIS beams using the newly indicated UL TCI associated with the new RIS mode.If the RIS mode is not changed (e.g., the RIS mode indicator does not indicate a switch), the WTRU may receive PDCCH and / or PDSCH via one or more RIS beams using the existing DL TCI and / or transmit PUCCH and / or PUSCH via one or more RIS beams using the existing UL TCI for the existing RIS mode.

[0136] A device (e.g., a wireless transmit / receive unit (WTRU)) may receive a first physical downlink shared channel (PDSCH) transmission using a first transmission configuration indicator (TCI) state associated with a base station and a second TCI state associated with a first reconfigurable intelligent surface (RIS) mode. The device may perform reference signal measurements associated with the base station and the RIS. The device may determine an interference level based on the reference signal measurement values. The device may determine a second RIS mode based on the interference level. The device may send a message to the base station. The message may indicate the second RIS mode. The device may receive an indication of a third RIS mode associated with a third TCI state. The third TCI state may be associated with the base station. The device may receive a second PDSCH transmission using the third TCI state.

[0137] Under the condition that the interference level is greater than the interference threshold, the second RIS mode may be determined to be the absorption mode. Under the condition that the third RIS mode exhibits the absorption mode, the device may deactivate the second TCI state associated with the first RIS mode. The message may indicate at least one of the reference signal measurement value or the interference level. The third RIS mode may be different from the second RIS mode. The device may activate the third TCI state based on the indication of the third RIS mode. The device may receive configuration information. The configuration information may indicate the respective associations between a plurality of TCI states and the RIS operation modes. The indication of the third RIS mode may be received in group common physical downlink control channel (GC-PDCCH) transmission.

[0138] A training phase for the RIS may be introduced. The WTRU may not measure (e.g., may not be able to measure) the interference from the RIS when the RIS is turned off, for example, because the RIS may not function when it is turned off. The training phase may be introduced for interference measurement. The RIS may be turned on, for example, periodically or aperiodically. The CSI-RS resources may be configured for interference measurement, for example, according to when the RIS is turned on. In an example of a RIS that is turned on periodically, the RIS may be on for a (pre-)configured window or duration for interference measurement and may be turned off (e.g., autonomously) after the measurement period. The RIS on / off state can be timer-based.

[0139] In an example of a RIS that is turned on aperiodically, the RIS can be triggered (e.g., by DCI or MAC CE) to be turned on. A (pre-)configured window or duration can be used for interference measurement and / or channel measurement. The window or duration can be indicated, for example, in DCI or MAC CE. The WTRU can perform interference measurement, for example, based on the indicated window or duration. The window or duration can be indicated in the trigger signal during the trigger phase, for example. The WTRU can perform interference measurement based on the (pre-)configured window or duration if the window or duration is not indicated (e.g., in the trigger signal during the trigger phase), for example. The window or duration indicated (e.g., in the trigger signal during the trigger phase) can override the configured or pre-configured window or duration.

[0140] The RIS controller may be turned off. The WTRU can perform interference measurement if, for example, some functions are permitted when the RIS is turned off and / or partially turned off. For example, the RIS controller may be turned off and the RIS reflector may not be turned off. The RIS that is partially off may reflect signals according to a default setting that cannot be adjusted or updated when the RIS controller is turned off, for example. The RIS operation mode and functions can be turned off. The RIS can receive signaling from the gNB and respond, for example, by turning on the operation mode and functions if an "on" indicator is received.

[0141] The RIS may be turned on or off at different levels. The RIS may be partially or fully turned on or off in different states. The RIS may turn on some functions and / or turn off other functions. The RIS may be turned on in some operating modes and / or turned off in other operating modes. The RIS can turn on the receiving mode and / or turn off the transmitting mode, and vice versa. The RIS may be turned on for signal or beam reflection and / or turned off for signal or beam refraction, or vice versa. The RIS may be turned on for signal or beam transmission and / or turned off for signal or beam reflection or refraction, or vice versa. A part of the RIS may be turned on and another part of the RIS may be turned off. How the RIS is turned on or off can be determined based on an instruction received from the gNB / TRP. How the RIS is turned on or off can be determined based on the feedback of the WTRU. The RIS can autonomously turn itself on or off. The RIS can autonomously turn itself on or off based on some condition, measurement, or criterion.

[0142] The mixed RIS types may be deployed in the same (e.g., the same) system. The WTRU may be configured using CSI-RS resources or resource sets for interference management. The WTRU may be composed of multiple RIS types. The WTRU may be configured by an association between RIS types and / or RS resources or resource sets. The RS resources or resource sets may be, for example, CSI-RS resources or resource sets, SSB resources or resource sets, etc. The CSI-RS resources or resource sets may be, for example, ZP-CSI-RS resources or resource sets, NZP-CSI-RS resources or resource sets, CSI interference measurement (CSI-IM) resources or resource sets, etc. Different RIS operations may cause different degrees of interference. The interference may become more dynamic, for example, when different RIS operations coexist within the same system. Interference management (IM), measurement, and / or reporting may be implemented.

[0143] The beam direction may be changed in the same operation mode, for example, to steer the interference beam away from the WTRU. The operation mode may be changed / switched from one operation mode to another, for example, to mitigate interference. For example, the RIS may be switched from a reflection mode to an absorption mode. The WTRU may be able to report interference to the gNB / TRP. The WTRU may be able to recommend the RIS operation mode to the gNB. The WTRU may be able to report the interference corresponding to the CSI-RS (e.g., having a recommended mode), for example, when the WTRU measures the CSI-RS (e.g., for IM, etc.).

[0144] An uplink / downlink (UL / DL) TDD configuration may be provided for the RIS-assisted system. In some examples, the RIS may use (e.g., may require) its own UL / DL TDD configuration. The configuration may depend on the RIS type (e.g., active, semi-active, or passive).

[0145] Each (e.g., every) WTRU having a link to a gNB via an RIS may be configured in a cell-specific UL / DL TDD configuration (e.g., only) (e.g., via tdd-UL-DL-ConfigurationCommon). The same UL / DL TDD configuration may be used for an RIS link independent of the RIS type (e.g., the link from the RIS to the gNB), e.g., if all (e.g., every) WTRUs connected via the RIS have the same slot configuration for UL / DL transmission.

[0146] Each (e.g., every) WTRU having a link to a gNB via an RIS may be configured in a cell-specific UL / DL TDD configuration (e.g., via tdd-UL-DL-ConfigurationCommon) and / or may be configured using a WTRU-specific UL / DL TDD configuration (e.g., via tdd-UL-DL-ConfigurationDedicated). Using the WTRU-specific UL / DL TDD configuration, flexible (e.g., not dedicated as UL or DL) slots and symbols signaled by tdd-UL-DL-ConfigurationCommon can be modified. The WTRU-specific UL / DL TDD configuration may be used for an RIS (e.g., the link from the RIS to the gNB) to accommodate the WTRU-specific UL / DL TDD configuration, e.g., if WTRUs connected via the RIS have different slot configurations for UL / DL transmission.

[0147] The gNB may configure a UL / DL TDD configuration for the RIS, where the same UL / DL allocation for flexible slots / symbols may be used for all (e.g., every) WTRUs having a link to the gNB via the RIS (e.g., if symbol = explicit in tdd-UL-DL-ConfigurationDedicated, symbol = allDownlink or symbol = allUplink or the same nrofDownlinkSymbols and nrofUplinkSymbols may be in the slot).

[0148] The gNB can configure the UL / DL TDD configuration for the RIS using several UL / DL patterns (e.g., in addition to Pattern 1 of the mandatory pattern and / or Pattern 2 of the optional pattern if necessary). The patterns can have the same (e.g., or similar) parameters, such as one or more of the following: transmission period, total number of slots, number of downlink and uplink slots, and / or number of downlink and uplink symbols. The parameters of each pattern can have the same value or different values from the parameters of another pattern. The number of patterns used for the RIS to accommodate the WTRU-specific UL / DL TDD configuration can be determined based on, for example, the number of WTRUs having a link to the gNB via the RIS and / or based on the transmission periodicity of each pattern. In some examples, the sum of the periodicities of each pattern (P1 + P2 +... + PN) can be divided by time (e.g., 20 ms) (e.g., to have the first symbol in a numbered radio frame, e.g., an even-numbered radio frame). The patterns can be concatenated and / or repeated (e.g., with the total periodicity of each pattern). The RIS type can be active or semi-active, for example, to reflect or absorb signals for the assigned transmission direction. The transmission signal to / from the WTRU can be absorbed by the RIS, for example, if the slots are each assigned to UL / DL.

[0149] The RIS type may be passive. The gNB may have different WTRU-specific UL / DL TDD configurations. The gNB may not be able to find the same UL / DL allocation of flexible slots / symbols for (e.g., all) WTRUs having a link with the gNB via the RIS. The gNB may determine an option (e.g., the best option) applied to a part (e.g., most) of the WTRUs. The gNB may configure a UL / DL TDD configuration for the RIS. If the configured UL / DL TDD slots do not meet their requirements, the gNB may not have to configure flexible slots for the WTRUs. The flexible slots may not be used for UL / DL transmission to these WTRUs.

[0150] The RIS may not be expected to have the tdd-UL-DL-ConfigurationDedicated indicate a symbol as uplink or downlink when the tdd-UL-DL-ConfigurationCommon indicates the symbol as downlink or uplink respectively.

[0151] Figure 19 shows an exemplary method for UL / DL TDD configuration for the RIS. The UL / DL TDD configuration for the RIS may be assigned, for example, based on the similarity of the WTRU-specific UL / DL TDD configurations for the WTRUs having a link with the gNB via the RIS and / or the RIS type. The RIS may not have to absorb signals coming from / going to the WTRU / gNB for UL / DL transmission, for example, when the RIS type is passive. The gNB may determine a TDD configuration option (e.g., the best TDD configuration option) for some (e.g., most) of the WTRUs connected via the RIS.

[0152] Timing information may be provided to align the transmission and reception boundaries for RIS-based systems or RIS-assisted systems. For example, depending on the RIS deployment, timing information for aligning the transmission may be used.

[0153] Timing information may not be required, for example, when the RIS is near the gNB (e.g., collocated with the gNB). For example, the RIS may be collocated with the gNB to enable RIS-based massive MIMO transmission.

[0154] The RIS may be away from the gNB (e.g., remotely located), for example, to improve the communication performance for a set of WTRUs and / or to extend the coverage area of the gNB. The link from the gNB to the RIS may have some latency, for example, when the RIS is located away from the gNB. A WTRU having a link with the gNB via the RIS (within the gNB coverage area with or without the RIS) may be affected, for example, due to latency on the link from the gNB to the RIS and / or from the WTRU to the RIS.

[0155] A link from the gNB to the RIS (e.g., only a single link from the gNB to the RIS) may be considered. Accordingly, timing advance adjustment for a WTRU having a link to the gNB via the RIS can be determined. The gNB can estimate (e.g., initially) the transmission timing alignment for a WTRU having a link to the gNB via the RIS. For example, the WTRU may be within the gNB coverage without the RIS (e.g., the RIS may be used to improve communication). The RIS can be used to extend the coverage area of the gNB. The timing information can be created by considering, for example, one or more of the cell's duplex mode, frequency range, propagation delay of the link from the gNB to the RIS, and / or any processing delay on the RIS. For example, the gNB can obtain the RIS processing delay as part of the feedback or capability message from the RIS. The gNB can estimate the timing information. The gNB can use the propagation delay information from a WTRU within the gNB coverage area (e.g., without the RIS) by comparing the link from the gNB to the WTRU (e.g., for the WTRU propagation delay) with the link from the gNB to the RIS / RIS to the WTRU to estimate the propagation and processing delays of the RIS.

[0156] The gNB can estimate the propagation delay (e.g., the entire path from the gNB to the RIS, from the RIS to the WTRU, etc.) (e.g., during the initial access phase). The propagation delay from the RIS to the WTRU can be estimated, for example, if the gNB knows in advance the propagation delay of the gNB to the RIS. The gNB can align the timing advance offset based on, for example, the gNB's estimated value of the transmission timing alignment for a WTRU having a link to the gNB via the RIS. There may be a single link between the gNB and the RIS. The gNB can configure the timing advance offset value based on, for example, the maximum delay (e.g., propagation and processing) estimation for a WTRU having a link to the gNB.

[0157] Figure 20 shows an example of timing advance offset alignment for a RIS-assisted system. As shown in Figure 20, two WTRUs may be in different positions and each has a link to the gNB via the RIS. The RIS may be located away from the gNB. The gNB can transmit a timing advance offset, for example, such that an uplink transmission from the WTRU arrives at the RIS and the gNB simultaneously.

[0158] Figure 21 shows an exemplary method of using timing information to align the transmission and reception boundaries for the RIS. As shown in Figure 21, the gNB can estimate (e.g., initially) the propagation delay of the WTRU, the propagation delay of the RIS, and the processing delay at the RIS. The gNB can determine whether the WTRU has a link to the gNB via the RIS. The gNB can align the timing advance offset value based on, for example, the highest total delay (e.g., including propagation and processing) such that the RIS and the gNB can receive the UL symbol timing simultaneously (e.g., if the WTRU has a link to the gNB via the RIS).

[0159] The features and elements described above are described in specific combinations, but each feature or element can be used alone without the other features and elements of the preferred embodiments, or can be used in various combinations with or without other features and elements.

[0160] The implementations described herein may consider 3GPP-specific protocols, but it should be understood that the implementations described herein are not limited to this scenario and may be applicable to other wireless systems. For example, the solutions described herein may consider LTE, LTE-A, New Radio (NR), or 5G-specific protocols, but it should be understood that the solutions described herein are not limited to this scenario and may also be applicable to other wireless systems. For example, the system has been described with reference to 3GPP, 5G, and / or NR network layers, but the envisioned embodiments extend beyond implementations that use specific network layer technologies. Similarly, potential implementations extend to all types of service layer architectures, systems, and embodiments. The techniques described herein can be applied independently and / or used in combination with other resource configuration techniques.

[0161] The processes described herein may be implemented in a computer program, software, and / or firmware incorporated in a computer-readable medium for execution by a computer and / or processor. Examples of computer-readable media include, but are not limited to, electronic signals (transmitted via wired and / or wireless connections) and computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, magnetic media such as read-only memory (ROM), random access memory (RAM), registers, cache memory, semiconductor memory devices, internal hard disks, and removable disks, magneto-optical media, and / or optical media such as Compact Disc (CD)-ROM disks and / or Digital Versatile Disk (DVD), among others. A processor associated with software may be used to implement a radio frequency transceiver for use in a WTRU, terminal, base station, RNC, and / or any host computer.

[0162] It is understood that the entity implementing the process described herein can be a logical entity stored in the memory of a mobile device, network node, or computer system and implemented in the form of software (e.g., computer-executable instructions) executed on its processor. That is, the process may be implemented in the form of software (e.g., computer-executable instructions) stored in the memory of a mobile device and / or a network node such as a node or computer system, and when executed by the processor of the node, the computer-executable instructions execute the discussed process. Also, it is understood that any transmission and reception processes illustrated in the figures can be implemented by the communication circuit of the node under the control of the processor of the node and the computer-executable instructions (e.g., software) it executes.

[0163] The various techniques described herein may be implemented in relation to hardware or software, or a combination of both as required. Accordingly, implementations of the subject matter described herein, the apparatus, or specific aspects or portions thereof may take the form of program code (e.g., instructions) embodied in a tangible medium including any other machine-readable storage medium, the program code being loaded and executed on a machine such as a computer, the machine becoming an apparatus for implementing the subject matter described herein. When the program code is stored in a medium, the program code may be stored in one or more media acting in concert, i.e., one or more media together contain the code for performing the actions, provided that in the case of there being more than one single medium, no particular portion of the code need be stored on any particular medium. In the case of program code execution on a programmable device, the computing device generally includes a processor, a storage medium readable by the processor (including volatile memory and non-volatile memory and / or storage elements), at least one input device, and at least one output device. One or more programs may implement or utilize the processes described herein in relation to the subject matter described herein, for example, through the use of an API, reusable controls, etc. Such programs are preferably implemented in a high-level procedural or object-oriented programming language for communicating with a computer system. However, the programs may be implemented in assembly language or machine language as required. In any case, the language may be a compiled or interpreted language and may also be combined with a hardware implementation.

[0164] Exemplary embodiments may refer to utilizing aspects of the subject matter described herein in the environment of one or more stand-alone computing systems, but the subject matter described herein is not so limited and may rather be implemented in connection with any computing environment such as a network or distributed computing environment. Still further, aspects of the subject matter described herein may be implemented within or across multiple processing chips or devices, and storage may be similarly affected across multiple devices. Such devices may include, by way of example, personal computers, network servers, handheld devices, supercomputers, or computers integrated into other systems such as automobiles and airplanes.

[0165] In describing preferred embodiments of the subject matter of this disclosure, specific terms are used for clarity as illustrated in the figures. However, the claimed subject matter is not intended to be limited to the specific terms so chosen, and it is to be understood that each specific element includes all technical equivalents that operate in a similar manner to achieve a similar purpose.

Claims

1. A wireless transmit / receive unit (WTRU) comprising a processor, the processor being configured to: Receive a first physical downlink shared channel (PDSCH) transmission using a first transmission configuration indicator (TCI) state associated with a base station and a second TCI state associated with a first reconfigurable intelligent surface (RIS) mode; Perform a reference signal measurement associated with the RIS; Determine an interference level based on the reference signal measurement; Determine a second RIS mode based on the interference level; Transmit a message to the base station, the message indicating the second RIS mode; Receive an indication of a third RIS mode associated with a third TCI state, the third TCI state being associated with the base station; Receive a second PDSCH transmission using the third TCI state. A wireless transmit / receive unit (WTRU) configured as described above.

2. The WTRU according to claim 1, wherein the second RIS mode is determined to be an absorption mode if the interference level is greater than an interference threshold.

3. The WTRU according to claim 1, wherein the second TCI state associated with the first RIS mode is deactivated if the third RIS mode indicates an absorption mode.

4. The WTRU according to claim 1, wherein the message further indicates at least one of the reference signal measurement or the interference level.

5. The WTRU according to claim 1, wherein the third RIS mode is different from the second RIS mode, and the processor is further configured to activate the third TCI state based on the indication of the third RIS mode.

6. The WTRU according to claim 1, wherein the processor is further configured to receive configuration information indicating an association between a plurality of TCI states and RIS operation modes.

7. The WTRU according to claim 1, wherein the indication of the third RIS mode is received in a group common physical downlink control channel (GC-PDCCH) transmission.

8. The WTRU according to claim 1, wherein the processor is configured to perform the reference signal measurement associated with the RIS includes the processor being configured to measure a reference signal received from the RIS.

9. A method comprising: receiving a first physical downlink shared channel (PDSCH) transmission using a first transmission configuration indicator (TCI) state associated with a base station and a second TCI state associated with a first reconfigurable intelligent surface (RIS) mode; performing a reference signal measurement associated with the RIS; determining an interference level based on the reference signal measurement value; determining a second RIS mode based on the interference level; transmitting a message to the base station, the message indicating the second RIS mode; receiving an indication of a third RIS mode associated with a third TCI state, the third TCI state being associated with the base station; receiving a second PDSCH transmission using the third TCI state; A method comprising the steps of:

10. The method according to claim 9, wherein the second RIS mode is determined to be an absorption mode on the condition that the interference level is greater than an interference threshold.

11. The method according to claim 9, wherein the second TCI state associated with the first RIS mode is deactivated on the condition that the third RIS mode indicates an absorption mode.

12. The method according to claim 9, wherein the message further indicates at least one of the reference signal measurement value or the interference level.

13. The method according to claim 9, wherein the third RIS mode is different from the second RIS mode, the indication of the third RIS mode is received in a group common physical downlink control channel (GC-PDCCH) transmission, and the method further includes activating the third TCI state based on the indication of the third RIS mode.

14. The method according to claim 9, further comprising receiving configuration information, the configuration information indicating an association between each of a plurality of TCI states and an RIS operation mode.

15. Performing the reference signal measurement associated with the RIS includes measuring a reference signal received from the RIS, the method according to claim 9.

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