Control information and TCI for reconfigurable smart surfaces

Abstract

Control information and transmit configuration indicators (TCIs) for a reconfigurable smart surface (RIS) are provided. 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 using a second TCI state associated with a first RIS mode. The WTRU may perform a reference signal measurement associated with the RIS. The WTRU may determine an interference level based on the reference signal measurement. The WTRU may determine a second RIS mode based on the interference level. The WTRU may transmit a message to the base station, wherein the message indicates the second RIS mode. The WTRU may receive an indication of a third RIS mode associated with a third TCI state, the third TCI state associated with the base station. The WTRU may receive a second PDSCH transmission using the third TCI state.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] 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 incorporated herein by reference in its entirety. Background Art

[0003] Mobile communications using wireless communications continue to evolve. The fifth generation may be referred to as 5G. Previous (legacy) mobile communications may be, for example, fourth generation (4G) Long Term Evolution (LTE). Summary of the invention

[0004] Systems, methods, and means for control information and transmission configuration indicators (TCIs) for reconfigurable smart surfaces (RIS) are described herein.

[0005] A device (e.g., a wireless transmit / receive unit (WTRU)) may receive a first physical downlink shared channel (PDSCH) transmission using a first transmit 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 measurements. 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.

[0006] Under the condition that the interference level is greater than an interference threshold, the second RIS mode may be determined as an absorption mode. Under the condition that the third RIS mode indicates an 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 following: the reference signal measurement 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 multiple TCI states and corresponding associations with RIS operating 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

[0007] Figure 1A is a system diagram illustrating an example communication system in which one or more disclosed embodiments may be implemented.

[0008] Figure 1B is a diagram showing that according to the embodiment Figure 1A A system diagram of an example wireless transmit / receive unit (WTRU) for use within a communication system is shown.

[0009] Figure 1C is a diagram showing that according to the embodiment Figure 1A System diagram of an example radio access network (RAN) and an example core network (CN) for use within a communication system is shown.

[0010] Figure 1D is a diagram showing that according to the embodiment Figure 1A System diagram of yet another example RAN and yet another example CN for use within the communication system shown.

[0011] Figure 2 An example of a reconfigurable smart surface system is shown.

[0012] Figure 3 An example of a reconfigurable smart surface (RIS) configured as a reflective RIS based on a RIS operation mode for beam reflection only is shown.

[0013] Figure 4 An example of a RIS configured as a reflection and transmission RIS based on a RIS operation mode for simultaneous reflection and transmission is shown.

[0014] Figure 5 An example of a TCI configuration of a RIS configured for simultaneous reflection and transmission is shown.

[0015] Figure 6 An example method for a mixed RIS TCI configuration of RIS types and RIS operating modes is shown.

[0016] Figure 7 An example method for hybrid RIS of multiple RIS with RIS mode switching and TCI reconfiguration is shown.

[0017] Figure 8 An example method for TCI activation and deactivation for RIS is shown.

[0018] Fig. 9 An example method for RIS operation of a RIS-based system or a RIS-assisted system is shown.

[0019] Fig.10 An example method for TCI activation and deactivation for a RIS-assisted system is shown.

[0020] Fig.11 An example method for indicating and updating TCI for a RIS-assisted system is shown.

[0021] Fig.12 An example method for TCI indication and updating for a RIS-assisted system is shown.

[0022] Fig.13 An example method of TCI indication and updating (eg, by simultaneous reflection and transmission) for a RIS-assisted system is shown.

[0023] Fig.14 An example method for PDSCH reception at a WTRU for RIS type and RIS mode based on WTRU feedback is shown.

[0024] Fig.15 An example method of RIS mode switching and TCI indication is shown.

[0025] Fig.16 An example method of RIS on-off information for efficient interference management is shown.

[0026] Fig.17 An example method for RIS on / off indication via a group RNTI is shown.

[0027] Fig.18 An example method of RIS mode switching and TCI indication based on interference level is shown.

[0028] Fig.19 An example method for UL / DL TDD configuration for RIS is shown.

[0029] Fig. 20 An example of timing advance offset alignment for a RIS-assisted system is shown.

[0030] Fig.21 An example method for aligning timing information for transmit and receive boundaries of a RIS is shown. DETAILED DESCRIPTION

[0031] Figure 1A1 is a diagram illustrating an example communication system 100 in which one or more disclosed embodiments may be implemented. The communication system 100 may be a multiple access system that provides content such as voice, data, video, messaging, broadcast, etc. to multiple wireless users. The communication system 100 may enable multiple wireless users to access such content through sharing of system resources (including wireless bandwidth). For example, the communication system 100 may employ one or more channel access methods such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single carrier FDMA (SC-FDMA), zero tail unique word DFT spread OFDM (ZT UW DTS-s OFDM), unique word OFDM (UW-OFDM), resource block filtered OFDM, filter bank multi-carrier (FBMC), etc.

[0032] like Figure 1A As shown, the communication system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, RAN 104 / 113, CN 106 / 115, public switched telephone network (PSTN) 108, Internet 110 and other networks 112, but it should be understood that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and / or network elements. Each of the WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and / or communicate in a wireless environment. By way of example, the WTRUs 102a, 102b, 102c, 102d (any of which may be referred to as a “station” and / or “STA”) may be configured to send and / or receive wireless signals and may include user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a subscription-based unit, a pager, a cellular phone, a personal digital assistant (PDA), a smart phone, a laptop, a netbook, a personal computer, a wireless sensor, a hotspot or Mi-Fi device, an Internet of Things (IoT) device, a watch or other wearable device, a head-mounted display (HMD), a vehicle, a drone, medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in an industrial and / or automated process chain environment), a consumer electronic device, a device operating on a commercial and / or industrial wireless network, etc. Any of the WTRUs 102a, 102b, 102c, and 102d may be interchangeably referred to as a UE.

[0033] The communication system 100 may also include a base station 114a and / or a base station 114b. Each of the base stations 114a, 114b may be any type of device that is configured to wirelessly interface with at least one of the WTRUs 102a, 102b, 102c, 102d to facilitate access to one or more communication networks, such as the CN 106 / 115, the Internet 110, and / or other networks 112. By way of example, the base stations 114a, 114b may be a base transceiver station (BTS), a Node B, an eNode B, a Home Node B, a Home eNode B, a gNB, an NR Node B, a site controller, an access point (AP), a wireless router, and the like. While the base stations 114a, 114b are each depicted as a single element, it will be appreciated that the base stations 114a, 114b may include any number of interconnected base stations and / or network elements.

[0034] The base station 114a may be part of the RAN 104 / 113, which may also include other base stations and / or network elements (not shown), such as a base station controller (BSC), a radio network controller (RNC), a relay node, etc. The base station 114a and / or the base station 114b may be configured to send and / or receive wireless signals on one or more carrier frequencies (which may be referred to as cells (not shown)). These frequencies may be in a licensed spectrum, an unlicensed spectrum, or a combination of licensed and unlicensed spectrums. A cell may provide coverage of wireless services to a specific geographic area, which may be relatively fixed or may change over time. The cell may be further divided into cell sectors. For example, a cell associated with the base station 114a may be divided into three sectors. Therefore, in one embodiment, the base station 114a may include three transceivers, i.e., one transceiver for each sector of the cell. In an embodiment, the base station 114a may employ multiple-input multiple-output (MIMO) technology and may utilize multiple transceivers for each sector of the cell. For example, beamforming may be used to send and / or receive signals in a desired spatial direction.

[0035] The base stations 114a, 114b may communicate with one or more of the WTRUs 102a, 102b, 102c, 102d over an air interface 116, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet (UV), visible light, etc.). The air interface 116 may be established using any suitable radio access technology (RAT).

[0036] More specifically, as noted above, the communication system 100 may be a multiple access system and may employ one or more channel access schemes such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, etc. For example, the base station 114a in the RAN 104 / 113 and the WTRUs 102a, 102b, 102c may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may use Wideband CDMA (WCDMA) to establish the air interface 115 / 116 / 117. WCDMA may include communication protocols such as High Speed ​​Packet Access (HSPA) and / or Evolved HSPA (HSPA+). HSPA may include High Speed ​​Downlink (DL) Packet Access (HSDPA) and / or High Speed ​​UL Packet Access (HSUPA).

[0037] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which may establish the air interface 116 using Long Term Evolution (LTE) and / or Advanced LTE (LTE-A) and / or Advanced LTE Pro (LTE-A Pro).

[0038] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as NR radio access, which may establish the air interface 116 using New Radio (NR).

[0039] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement multiple radio access technologies. For example, the base station 114a and the WTRUs 102a, 102b, 102c may together implement LTE radio access and NR radio access, for example using the dual connectivity (DC) principle. Thus, the air interface used by the WTRUs 102a, 102b, 102c may be characterized by multiple types of radio access technologies and / or transmissions transmitted to / from multiple types of base stations (e.g., eNBs and gNBs).

[0040] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement radio technologies such as IEEE 802.11 (i.e., Wireless Fidelity (WiFi)), IEEE 802.16 (i.e., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile Communications (GSM), Enhanced Data rates for GSM Evolution (EDGE), GSM EDGE (GERAN), etc.

[0041] Figure 1A The base station 114b in the may be, for example, a wireless router, a Home NodeB, a Home eNodeB, or an access point, and may utilize any suitable RAT to facilitate wireless connectivity in local areas such as commercial venues, homes, vehicles, campuses, industrial facilities, sky corridors (e.g., for use by drones), roads, and the like. In one embodiment, the base station 114b and the WTRUs 102c, 102d may implement radio technologies such as IEEE 802.11 to establish a wireless local area network (WLAN). In an embodiment, the base station 114b and the WTRUs 102c, 102d may implement radio technologies such as IEEE 802.15 to establish a wireless personal area network (WPAN). In yet another embodiment, the base station 114b and the WTRUs 102c, 102d may utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR, etc.) to establish a picocell or a femtocell. As Figure 1A As shown, base station 114b may have a direct connection to Internet 110. Therefore, base station 114b may not need to access Internet 110 via CN 106 / 115.

[0042] The RAN 104 / 113 may be in communication with the CN 106 / 115, which may be any type of network configured to provide voice, data, applications, and / or Voice over Internet Protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. The data may have different quality of service (QoS) requirements, such as different throughput requirements, latency requirements, error tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, etc. The CN 106 / 115 may provide call control, billing services, mobile location-based services, prepaid calling, Internet connectivity, video distribution, etc., and / or perform advanced security functions, such as user authentication. Although not described in detail in the text, the CN 106 / 115 may be configured to provide voice, data, applications, and / or Voice over Internet Protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. The data may have different quality of service (QoS) requirements, such as different throughput requirements, latency requirements, error tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, etc. The CN 106 / 115 may provide call control, billing services, mobile location-based services, prepaid calling, Internet connectivity, video distribution, etc., and / or perform advanced security functions, such as user authentication. Figure 1AAlthough not shown in the figure, it will be appreciated that the RAN 104 / 113 and / or the CN 106 / 115 may be in direct or indirect communication with other RANs that employ the same RAT as the RAN 104 / 113 or a different RAT. For example, in addition to being connected to the RAN 104 / 113, which may utilize NR radio technology, the CN 106 / 115 may also be in communication with another RAN (not shown) that employs GSM, UMTS, CDMA 2000, WiMAX, E-UTRA, or WiFi radio technology.

[0043] The CN 106 / 115 may also serve as a gateway for the WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the Internet 110, and / or other networks 112. The PSTN 108 may include a circuit-switched telephone network that provides plain old telephone service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices that use common communication protocols, such as the Transmission Control Protocol (TCP), the User Datagram Protocol (UDP), and / or the Internet Protocol (IP) in the TCP / IP Internet protocol suite. The networks 112 may include wired communication networks and / or wireless communication networks owned and / or operated by other service providers. For example, the networks 112 may include another CN connected to one or more RANs, which may employ the same RAT as the RAN 104 / 113 or a different RAT.

[0044] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communication system 100 may include multi-mode capabilities (e.g., the WTRUs 102a, 102b, 102c, 102d may include multiple transceivers for communicating with different wireless networks via different wireless links). Figure 1A The illustrated WTRU 102c may be configured to communicate with the base station 114a, which may employ a cellular-based radio technology, and with the base station 114b, which may employ an IEEE 802 radio technology.

[0045] Figure 1B is a system diagram illustrating an example WTRU 102. Figure 1B As shown, the WTRU 102 may include, among other things, a processor 118, a transceiver 120, a transmit / receive element 122, a speaker / microphone 124, a keypad 126, a display / touchpad 128, non-removable memory 130, removable memory 132, a power source 134, a global positioning system (GPS) chipset 136, and / or other peripherals 138. It will be appreciated that the WTRU 102 may include any sub-combination of the foregoing elements while remaining consistent with an embodiment.

[0046] The processor 118 may be a general purpose processor, a special purpose processor, a conventional processor, a digital signal processor (DSP), a plurality of microprocessors, one or more microprocessors associated with a DSP core, a controller, a microcontroller, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) circuit, any other type of integrated circuit (IC), a state machine, etc. The processor 118 may perform signal decoding, data processing, power control, input / output processing, and / or any other functionality that enables the WTRU 102 to operate in a wireless environment. The processor 118 may be coupled to the transceiver 120, which may be coupled to the transmit / receive element 122. Although Figure 1B The processor 118 and the transceiver 120 are depicted as separate components, but it is understood that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip.

[0047] The send / receive element 122 may be configured to send a signal to a base station (e.g., base station 114a) or receive a signal from the base station via an air interface 116. For example, in one embodiment, the send / receive element 122 may be an antenna configured to send and / or receive an RF signal. In an embodiment, the send / receive element 122 may be a transmitter / detector configured to send and / or receive, for example, IR, UV or visible light signals. In another embodiment, the send / receive element 122 may be configured to send and / or receive both RF signals and optical signals. It should be understood that the send / receive element 122 may be configured to send and / or receive any combination of wireless signals.

[0048] Although the transmit / receive element 122 Figure 1B 1 as a single element, the WTRU 102 may include any number of transmit / receive elements 122. More specifically, the WTRU 102 may employ MIMO technology. Thus, in one embodiment, the WTRU 102 may include two or more transmit / receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals over the air interface 116.

[0049] The transceiver 120 may be configured to modulate signals to be transmitted by the transmit / receive element 122 and to demodulate signals received by the transmit / receive element 122. As noted above, the WTRU 102 may have multi-mode capabilities. For example, the transceiver 120 may include multiple transceivers for enabling the WTRU 102 to communicate via multiple RATs, such as NR and IEEE 802.11.

[0050] The processor 118 of the WTRU 102 may be coupled to and may receive user input data from a speaker / microphone 124, a keypad 126, and / or a display / touchpad 128 (e.g., a liquid crystal display (LCD) display unit or an organic light emitting diode (OLED) display unit). The processor 118 may also output user data to the speaker / microphone 124, the keypad 126, and / or the display / touchpad 128. In addition, the processor 118 may access information from and store data in any type of suitable memory, such as a non-removable memory 130 and / or a removable memory 132. The non-removable memory 130 may include a random access memory (RAM), a read-only memory (ROM), a hard disk, or any other type of memory storage device. The removable memory 132 may include a subscriber identity module (SIM) card, a memory stick, a secure digital (SD) memory card, and the like. In other embodiments, the processor 118 may access information from and store data in a memory that is not physically located on the WTRU 102, such as on a server or a home computer (not shown).

[0051] The processor 118 may receive power from the power source 134, and may be configured to distribute and / or control power to other components in the WTRU 102. The power source 134 may be any suitable device for powering the WTRU 102. For example, the power source 134 may include one or more dry cell batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel-metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, etc.

[0052] The processor 118 may also be coupled to the GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) regarding the current location of the WTRU 102. In addition to or in lieu of the information from the GPS chipset 136, the WTRU 102 may receive location information from a base station (e.g., base stations 114a, 114b) over the air interface 116 and / or determine its location based on the timing of signals received from two or more nearby base stations. It will be appreciated that the WTRU 102 may acquire location information by any suitable location-determination method while remaining consistent with an embodiment.

[0053] The processor 118 may also be coupled to other peripherals 138, which may include one or more software modules and / or hardware modules that provide additional features, functionality, and / or wired or wireless connectivity. For example, the peripherals 138 may include an accelerometer, an electronic compass, a satellite transceiver, a digital camera (for photos and / or video), a universal serial bus (USB) port, a vibration device, a television transceiver, a hands-free headset, module, a frequency modulation (FM) radio unit, a digital music player, a media player, a video game player module, an Internet browser, a virtual reality and / or augmented reality (VR / AR) device, an activity tracker, etc. Peripheral device 138 may include one or more sensors, which may be one or more of the following: a gyroscope, an accelerometer, a Hall effect sensor, a magnetometer, an orientation sensor, a proximity sensor, a temperature sensor, a time sensor; a geolocation sensor; an altimeter, a light sensor, a touch sensor, a magnetometer, a barometer, a gesture sensor, a biometric sensor, and / or a humidity sensor.

[0054] The WTRU 102 may include a full-duplex radio for which transmission and reception of some or all signals (e.g., associated with specific subframes for UL (e.g., for transmission) and downlink (e.g., for reception)) may be concurrent and / or simultaneous. The full-duplex radio may include an interference management unit for reducing and / or substantially eliminating self-interference via signal processing performed via hardware (e.g., a choke) or via a processor (e.g., a separate processor (not shown) or via the processor 118). In an embodiment, the WRTU 102 may include a half-duplex radio for which transmission and reception of some or all signals (e.g., associated with specific subframes for UL (e.g., for transmission) or downlink (e.g., for reception)) may be performed.

[0055] Figure 1C 1 is a system diagram showing the RAN 104 and the CN 106 in accordance with an embodiment. As noted above, the RAN 104 may employ an E-UTRA radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 104 may also be in communication with the CN 106.

[0056] The RAN 104 may include evolved Node-Bs 160a, 160b, 160c, though it will be appreciated that the RAN 104 may include any number of evolved Node-Bs while remaining consistent with an embodiment. The evolved Node-Bs 160a, 160b, 160c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In one embodiment, the evolved Node-Bs 160a, 160b, 160c may implement MIMO technology. Thus, the evolved Node-B 160a, for example, may use multiple antennas to transmit wireless signals to and / or receive wireless signals from the WTRU 102a.

[0057] Each of the evolved Node Bs 160a, 160b, 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the UL and / or DL, etc. Figure 1C As shown, the eNode-Bs 160a, 160b, 160c may communicate with one another via an X2 interface.

[0058] Figure 1C The illustrated CN 106 may include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (or PGW) 166. While each of the foregoing elements is depicted as being part of the CN 106, it should be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0059] The MME 162 may be connected to each of the evolved Node-Bs 162a, 162b, 162c in the RAN 104 via an S1 interface and may serve as a control node. For example, the MME 162 may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, bearer activation / deactivation, selecting a particular serving gateway during an initial attach of the WTRUs 102a, 102b, 102c, etc. The MME 162 may provide a control plane function for switching between the RAN 104 and other RANs (not shown) that employ other radio technologies, such as GSM and / or WCDMA.

[0060] The SGW 164 may be connected to each of the evolved Node-Bs 160a, 160b, 160c in the RAN 104 via an S1 interface. The SGW 164 may generally route and forward user data packets to / from the WTRUs 102a, 102b, 102c. The SGW 164 may perform other functions, such as anchoring the user plane during an inter-evolved Node-B handover, triggering paging when DL data is available for the WTRUs 102a, 102b, 102c, managing and storing the context of the WTRUs 102a, 102b, 102c, and the like.

[0061] The SGW 164 may be connected to the PGW 166, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices.

[0062] The CN 106 may facilitate communications with other networks. For example, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to circuit-switched networks, such as the PSTN 108, to facilitate communications between the WTRUs 102a, 102b, 102c and traditional land-line communications devices. For example, the CN 106 may include, or may be in communication with, an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that acts as an interface between the CN 106 and the PSTN 108. In addition, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired networks and / or wireless networks owned and / or operated by other service providers.

[0063] Although the WTRU Figures 1A to 1D Although described as wireless terminals, it is contemplated that in certain representative embodiments, such terminals may (eg, temporarily or permanently) use a wired communication interface with a communication network.

[0064] In a representative embodiment, the other network 112 may be a WLAN.

[0065] A WLAN in infrastructure basic service set (BSS) mode may have an access point (AP) for the BSS and one or more stations (STA) associated with the AP. The AP may have access or an interface to a distribution system (DS) or another type of wired / wireless network that carries traffic to and / or carries traffic away from the BSS. Traffic originating from outside the BSS and leading to the STA may be reached by the AP and may be delivered to the STA. Traffic originating from the STA and leading to a destination outside the BSS may be transmitted to the AP to be delivered to the corresponding destination. Traffic between STAs within the BSS may be transmitted by the AP, for example, wherein the source STA may transmit traffic to the AP, and the AP may deliver traffic to the target STA. Traffic between STAs within the BSS may be considered and / or referred to as point-to-point traffic. Direct link establishment (DLS) may be used to transmit point-to-point traffic between the source STA and the target STA (e.g., directly between them). In certain representative embodiments, the DLS may use 802.11e DLS or 802.11z tunnel DLS (TDLS). A WLAN using an independent BSS (IBSS) mode may not have an AP, and STAs within or using the IBSS (eg, all STAs in the STA) may communicate directly with each other. The IBSS communication mode may sometimes be referred to herein as an "ad hoc" communication mode.

[0066] When using the 802.11ac infrastructure operating mode or a similar operating mode, the AP may send a beacon on a fixed channel (such as a primary channel). The primary channel may be a fixed width (e.g., a 20 MHz wide bandwidth) or a width dynamically set via signaling. The primary channel may be a working channel of the BSS and may be used by the STA to establish a connection with the AP. In certain representative embodiments, carrier sense multiple access / collision avoidance (CSMA / CA) may be implemented, for example, in an 802.11 system. For CSMA / CA, a STA (e.g., each STA) (including the AP) may sense the primary channel. If the primary channel is sensed / detected and / or determined to be busy by a particular STA, the particular STA may back off. One STA (e.g., only one station) may transmit at any given time in a given BSS.

[0067] High throughput (HT) STAs may communicate using a 40 MHz wide channel, for example, via a combination of a primary 20 MHz channel and adjacent or non-adjacent 20 MHz channels to form a 40 MHz wide channel.

[0068] Very high throughput (VHT) STA can support 20MHz, 40MHz, 80MHz and / or 160MHz wide channels. 40MHz channels and / or 80MHz channels can be formed by combining continuous 20MHz channels. 160MHz channels can be formed by combining 8 continuous 20MHz channels, or by combining two non-continuous 80MHz channels (this can be called 80+80 configuration). For 80+80 configuration, after channel coding, the data can pass through a segment parser that can divide the data into two streams. Each stream can be processed by inverse fast Fourier transform (IFFT) and time domain processing separately. These streams can be mapped to two 80MHz channels, and data can be sent by sending STA. At the receiver of the receiving STA, the above-mentioned operation for 80+80 configuration can be reversed, and the combined data can be transmitted to the medium access control (MAC).

[0069] 802.11af and 802.11ah support operating modes below 1GHz. Channel operating bandwidths and carriers are reduced in 802.11af and 802.11ah relative to those used in 802.11n and 802.11ac. 802.11af supports 5MHz, 10MHz, and 20MHz bandwidths in the TV White Space (TVWS) spectrum, and 802.11ah supports 1MHz, 2MHz, 4MHz, 8MHz, and 16MHz bandwidths using non-TVWS spectrum. According to a representative embodiment, 802.11ah may support instrument type control / machine type communications, such as MTC devices in macro coverage areas. MTC devices may have certain capabilities, such as limited capabilities, including support for (e.g., only support for) certain bandwidths and / or limited bandwidths. MTC devices may include batteries with battery life above a threshold (e.g., to maintain very long battery life).

[0070] WLAN systems that can support multiple channels and channel bandwidths (such as 802.11n, 802.11ac, 802.11af, and 802.11ah) include channels that can be designated as primary channels. The primary channel may have a bandwidth equal to the maximum common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel may be set and / or limited by a STA (which supports the minimum bandwidth operation mode) from all STAs operating in the BSS. In the example of 802.11ah, for STAs (e.g., MTC-type devices) that support (e.g., only support) a 1MHz mode, the primary channel may be 1MHz wide, even if the AP and other STAs in the BSS support 2MHz, 4MHz, 8MHz, 16MHz, and / or other channel bandwidth operation modes. Carrier sensing and / or network allocation vector (NAV) settings may depend on the state of the primary channel. If the primary channel is busy, for example, because a STA (supporting only a 1MHz operation mode) is sending to the AP, the entire available frequency band may be considered busy even if most of the frequency bands remain idle and may be available.

[0071] In the United States, the available frequency band for 802.11ah is 902MHz to 928MHz. In South Korea, the available frequency band is 917.5MHz to 923.5MHz. In Japan, the available frequency band is 916.5MHz to 927.5MHz. The total bandwidth available for 802.11ah is 6MHz to 26MHz, depending on the country code.

[0072] Figure 1D 1 is a system diagram showing the RAN 113 and the CN 115 in accordance with an embodiment. As noted above, the RAN 113 may employ NR radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 113 may also be in communication with the CN 115.

[0073] The RAN 113 may include gNBs 180a, 180b, 180c, though it will be appreciated that the RAN 113 may include any number of gNBs while remaining consistent with an embodiment. The gNBs 180a, 180b, 180c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In one embodiment, the gNBs 180a, 180b, 180c may implement MIMO technology. For example, the gNBs 180a, 180b may utilize beamforming to send signals to and / or receive signals from the gNBs 180a, 180b, 180c. Thus, the gNB 180a may, for example, use multiple antennas to send wireless signals to and / or receive wireless signals from the WTRU 102a. In an embodiment, the gNBs 180a, 180b, 180c may implement carrier aggregation technology. For example, gNB 180a may transmit multiple component carriers to WTRU 102a (not shown). A subset of these component carriers may be on unlicensed spectrum, while the remaining component carriers may be on licensed spectrum. In an embodiment, gNBs 180a, 180b, 180c may implement coordinated multi-point (CoMP) technology. For example, WTRU 102a may receive coordinated transmissions from gNB 180a and gNB 180b (and / or gNB 180c).

[0074] The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using transmissions associated with parameter sets that may be scalable. For example, OFDM symbol spacing and / or OFDM subcarrier spacing may vary for different transmissions, different cells, and / or different portions of the wireless transmission spectrum. The WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using subframes or transmit time intervals (TTIs) of varying or scalable lengths (e.g., containing different numbers of OFDM symbols and / or varying absolute time lengths over time).

[0075] The gNBs 180a, 180b, 180c may be configured to communicate with the WTRUs 102a, 102b, 102c in a standalone configuration and / or a non-standalone configuration. In a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c while not accessing other RANs (e.g., such as the eNodeBs 160a, 160b, 160c). In a standalone configuration, the WTRUs 102a, 102b, 102c may use one or more of the gNBs 180a, 180b, 180c as mobility anchors. In a standalone configuration, the WTRUs 102a, 102b, 102c may communicate with the gNBs 180a, 180b, 180c using signals in an unlicensed band. In a non-standalone configuration, the WTRUs 102a, 102b, 102c may communicate / connect with the gNB 180a, 180b, 180c while also communicating / connecting with another RAN, such as the eNode-B 160a, 160b, 160c. For example, the WTRUs 102a, 102b, 102c may implement the DC principle to communicate with one or more gNBs 180a, 180b, 180c and one or more eNode-Bs 160a, 160b, 160c substantially simultaneously. In a non-standalone configuration, the eNode-B 160a, 160b, 160c may act as a mobility anchor for the WTRUs 102a, 102b, 102c, and the gNB 180a, 180b, 180c may provide additional coverage and / or throughput for serving the WTRUs 102a, 102b, 102c.

[0076] Each of the gNBs 180a, 180b, 180c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in UL and / or DL, support of network slicing, dual connectivity, interworking between NR and E-UTRA, routing of user plane data towards a user plane function (UPF) 184a, 184b, routing of control plane information towards an access and mobility management function (AMF) 182a, 182b, etc. Figure 1D As shown, gNBs 180a, 180b, and 180c may communicate with each other via an Xn interface.

[0077] Figure 1DThe illustrated CN 115 may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one session management function (SMF) 183a, 183b, and possible data networks (DNs) 185a, 185b. Although each of the foregoing elements is depicted as part of the CN 115, it should be understood that any of these elements may be owned and / or operated by an entity other than the CN operator.

[0078] The AMF 182a, 182b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via the N2 interface and may act as a control node. For example, the AMF 182a, 182b may be responsible for authenticating users of the WTRU 102a, 102b, 102c, support of network slicing (e.g., handling of different PDU sessions with different requirements), selecting a specific SMF 183a, 183b, management of registration areas, termination of NAS signaling, mobility management, etc. The AMF 182a, 182b may use network slicing to customize CN support for the WTRU 102a, 102b, 102c based on the type of services utilized by the WTRU 102a, 102b, 102c. For example, different network slices may be established for different use cases, such as services relying on ultra-reliable low latency (URLLC) access, services relying on enhanced mobile broadband (eMBB) access, services for machine type communication (MTC) access, etc. The AMF 162 may provide a control plane function for switching between the RAN 113 and other RANs (not shown) that employ other radio technologies, such as LTE, LTE-A, LTE-A Pro, and / or non-3GPP access technologies, such as WiFi.

[0079] The SMF 183a, 183b may be connected to the AMF 182a, 182b in the CN 115 via the N11 interface. The SMF 183a, 183b may also be connected to the UPF 184a, 184b in the CN 115 via the N4 interface. The SMF 183a, 183b may select and control the UPF 184a, 184b, and configure the traffic routing through the UPF 184a, 184b. The SMF 183a, 183b may perform other functions, such as managing and allocating UE IP addresses, managing PDU sessions, controlling policy implementation and QoS, providing downlink data notification, etc. The PDU session type may be IP-based, non-IP-based, Ethernet-based, etc.

[0080] The UPF 184a, 184b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 113 via the N3 interface, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices. The UPF 184, 184b may perform other functions, such as routing and forwarding packets, enforcing user plane policies, supporting multi-homed PDU sessions, handling user plane QoS, buffering downlink packets, providing mobility anchoring, etc.

[0081] The CN 115 may facilitate communications with other networks. For example, the CN 115 may include or may communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) that acts as an interface between the CN 115 and the PSTN 108. In addition, the CN 115 may provide the WTRUs 102a, 102b, 102c with access to other networks 112, which may include other wired networks and / or wireless networks owned and / or operated by other service providers. In one embodiment, the WTRUs 102a, 102b, 102c may be connected to local data networks (DNs) 185a, 185b via the UPF 184a, 184b via the N3 interface to the UPF 184a, 184b and the N6 interface between the UPF 184a, 184b and the DN 185a, 185b.

[0082] Given that Figures 1A to 1D as well as Figures 1A to 1D Corresponding to the description of the present invention, one or more or all of the functions described herein with reference to one or more of the following may be performed by one or more simulation devices (not shown): WTRU102a-d, base station 114a-b, evolved Node B 160a-c, MME 162, SGW 164, PGW 166, gNB 180a-c, AMF182a-b, UPF 184a-b, SMF 183a-b, DN 185a-b and / or any other device described herein. The simulation device may be one or more devices configured to emulate one or more or all of the functions described herein. For example, the simulation device may be used to test other devices and / or simulate network and / or WTRU functions.

[0083] The simulation device may be designed to implement one or more tests of other devices in a laboratory environment and / or in an operator network environment. For example, one or more simulation devices may perform one or more functions or all functions while being fully or partially implemented and / or deployed as part of a wired and / or wireless communication network in order to test other devices within the communication network. One or more simulation devices may perform one or more functions or all functions while being temporarily implemented / deployed as part of a wired and / or wireless communication network. The simulation device may be directly coupled to another device for testing purposes and / or may use over-the-air wireless communications to perform testing.

[0084] One or more simulation devices can perform one or more (including all) functions without being implemented / deployed as part of a wired and / or wireless communication network. For example, the simulation device can be used in a test scenario in a test laboratory and / or a non-deployed (e.g., testing) wired and / or wireless communication network to implement testing of one or more components. One or more simulation devices can be test equipment. Direct RF coupling and / or wireless communication via RF circuits (e.g., which may include one or more antennas) can be used by the simulation device to send and / or receive data.

[0085] The WTRU may 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), for example, via a RIS for a reconfigurable intelligent surface (RIS) assisted system (e.g., based on a RIS type and / or a RIS operation mode). The WTRU may be configured with reference signal (RS) resources, for example, based on a RIS type and / or a RIS operation mode.

[0086] The WTRU may perform, for example, one or more of the following: receive configuration information having one or more transmit configuration indicator (TCI) states and / or associations with a RIS (e.g., based on a RIS type and / or RIS operating mode); activate a TCI state for beamforming information in a RIS assisted system; receive a TCI indication for beam information received or transmitted via the RIS; decode a PDCCH with a RIS radio network temporary identifier (RIS-RNTI) and / or a group common PDCCH (GC-PDCCH) with a RIS-GC-RNTI; indicate a RIS operating mode change or switch; switch a TCI state indicated in the TCI, for example, based on a new RIS operating mode TCI that may be indicated, for example, with the mode indication (e.g., if the RIS mode has not changed, the TCI may not be changed); update); for example, if the RIS operation mode is the absorption mode, deactivate one or more TCI states of beamforming information corresponding to the absorption operation (for example, based on the RIS absorption mode); for the new RIS mode, receive PDCCH and / or PDSCH via one or more RIS beams using the newly indicated TCI for downlink (DL); for the new RIS mode, send PUCCH and / or PUSCH via one or more RIS beams using the newly indicated TCI for uplink (UL); and / or for the existing RIS mode, for example, if the RIS mode is not changed, receive PDCCH and / or PDSCH via one or more RIS beams using the existing TCI for DL, or send PUCCH and / or PUSCH via one or more RIS beams using the existing TCI for UL.

[0087] For a RIS-assisted system, the RIS may be turned on or off or activated or deactivated.A WTRU may be configured with and / or associated with one or more RISs for a RIS-assisted system.

[0088] The WTRU may measure interference on primary RS resources for a gNB / transmit-receive point (TRP) in a RIS assisted system (e.g., may perform reference signal measurements associated with a base station and determine an interference level based on the reference signal measurements). The WTRU may measure interference on secondary RS resources for an associated RIS in a RIS assisted system (e.g., may perform reference signal measurements associated with the RIS and determine an interference level based on the reference signal measurements). The WTRU may send the interference measurement (e.g., the interference level) to the gNB / TRP. The WTRU may send a recommended RIS operation mode to the gNB / TRP (e.g., may transmit a message to the base station, wherein the message indicates the recommended RIS operation mode). The WTRU may send the recommended RIS operation mode to the gNB / TRP along with the interference measurement (e.g., the interference level) for the RIS (e.g., the message sent to the base station may indicate the interference level). For example, the recommended RIS operation mode may be based on a first (pre) configured threshold. For example, the WTRU may determine the interference level based on the reference signal measurement and determine the recommended RIS operation mode based on the interference level. For example, under the condition that the interference level is greater than a first (pre)configured threshold (e.g., interference threshold), the recommended RIS operation mode may be absorption mode. The WTRU may send a recommendation to the gNB / TRP to turn on or off the RIS; and / or send a recommendation to the gNB / TRP to turn on or off the RIS and interference measurements for the RIS (e.g., the recommendation to turn on / off the RIS may be based on a second (pre)configured threshold).

[0089] The gNB / TRP may perform, for example, one or more of the following: receive WTRU feedback; determine whether to turn RIS on or off (e.g., based on WTRU feedback); determine whether to activate or deactivate RIS (e.g., based on WTRU feedback); determine whether to switch the RIS operating mode and which mode to switch to (e.g., based on WTRU feedback, e.g., WTRU feedback may be a recommended RIS operating mode and / or interference measurement; WTRU feedback may be carried periodically, semi-periodically and / or aperiodically in PUCCH and / or PUSCH); and / or indicate that RIS is to be turned on / off (e.g., the indication may be carried in GC-PDCCH, MAC CE, or RRC signaling, where the container to be used may depend on the payload size).

[0090] The RIS may perform, for example, one or more of the following: receive configuration information for a RIS-RNTI or a RIS-GC-RNTI; receive an indication to turn on / off RIS from a gNB / TRP (e.g., via a PDCCH with a RIS-RNTI or a GC-PDCCH with a RIS-GC-RNTI); receive an indication to activate / deactivate RIS from a gNB / TRP; receive a GC-PDCCH, e.g., if the payload size is small and / or if fast on / off is required; receive a MAC CE or RRC, e.g., if the payload size is large and / or if fast on / off is not required; turn on / off RIS based on the received indication; and / or activate / deactivate RIS based on the received indication.

[0091] A TCI framework may be implemented. A unified TCI may support (e.g., a single) TRP. A non-uniform TCI may support operations such as multiple (e.g., up to two) TRP operations (e.g., coherent joint transmission among TRPs is not supported). A non-uniform TCI may support indications of multiple (e.g., up to two) TCI states and (e.g., one) TCI code point. TCI may support frequency ranges of FR1 and / or FR2.

[0092] Multi-TRP operation can support one or more of the following: dynamic TRP selection and / or mobility measurements for multi-beam / multi-TRP deployments (e.g., up to 64 synchronization signal blocks (SSBs) per cell), PDSCH transmissions for enhanced mobile broadband (eMBB), multi-TRP diversity for ultra-reliable and low-latency communications (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.

[0093] A channel state information reference signal (CSI-RS) framework may be implemented. CSI interference measurements may be based on zero power CSI-RS (ZP-CSI-RS) and / or non-zero power CSI-RS (NZP-CSI-RS) resources. CSI-RS operations may support type II codebooks for high-resolution CSI feedback and / or CSI enhancement for multi-TRP non-coherent joint transmission (NCJT), etc.

[0094] A reconfigurable smart 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 tunable scattering of electromagnetic (EM) waves. These surfaces can have reflective, refractive and absorptive properties that can be reconfigured and adapted to a specific radio channel environment using a microcontroller (e.g., a field programmable gate array (FPGA)). The configuration of the RIS can be handled or assisted by the network through a (e.g., separate) control signaling link for exchanging (e.g., related) side control information.

[0095] RIS can support the implementation of an intelligent and reconfigurable wireless environment for a wireless communication system. RIS can be a flat surface with a certain (e.g., large) number of elements. (Each) element can (e.g., independently) cause a controllable amplitude and / or phase change to an incident signal. Dense deployment of RIS in a wireless network can support flexible reconfiguration of wireless channels between a transmitter and a receiver, for example to achieve a desired implementation and distribution, which can reduce wireless channel fading and interference and / or improve wireless communication capacity and reliability. RIS can create a virtual line of sight (LoS) link (e.g., to bypass obstacles via intelligent reflection). RIS can add a signal path toward a desired direction, which can improve channel rank, refine channel statistics and / or distribution, and / or suppress or eliminate interference.

[0096] RIS (e.g., as opposed to active antenna arrays) can be integrated into existing wireless systems (e.g., cellular network systems). RIS can be deployed (e.g., on a large scale) in wireless networks, for example to significantly (e.g., and cost-effectively) enhance spectral and energy efficiency. RIS implementations can modify wireless system / network designs, for example, from a multiple-input multiple-output (MIMO) system without RIS to a RIS-assisted MIMO system. RIS can be more densely deployed in wireless networks at a lower cost than other wireless communication technologies.

[0097] Figure 2 An example of a reconfigurable smart surface system is shown.

[0098] RIS-assisted network deployments may be based on use cases and deployment considerations. Example RIS-integrated system deployments may include, for example, RIS-based massive MIMO and / or RIS-based coverage enhancement. In the example of a RIS-based massive MIMO system, the RIS may be deployed gNB / TRP (e.g., next to the gNB / TRP) to improve spectral efficiency. In the example of RIS-based coverage enhancement, the RIS may be deployed away from the gNB / TRP to enhance coverage in weak coverage areas and / or coverage holes (e.g., due to obstruction of the line-of-sight link between the gNB / TRP and the WTRU) and / or to extend the coverage area for the gNB / TRP.

[0099] Control information (e.g., including side control information), beamforming related signaling, TCI indications, control information for beamforming and beam management, configurations, quasi co-location (QCL), etc. may be based on the assumption of transmitter (Tx) and receiver (Rx) beam pairs without the presence of one or more reconfigurable intelligent surface (RIS) nodes. Processes related to communication may be affected in a RIS integrated system. The side control information may enable the (e.g., integrated) RIS to operate efficiently and / or effectively. Mechanisms for exchanging control information (e.g., including side control information), such as beamforming information, on / off information, UL / DL time domain duplex (TDD) configuration information, TCI configuration, activation, indications, interference management and associated signaling, reference signals and related processes, etc., may be implemented for a RIS integrated system, and the RIS may affect control information and signaling implementation and / or TCI operation. UL / DL TDD timeslots may be configured for a RIS and a WTRU having a link to a gNB via the RIS. For example, the timing advance offset value may be aligned for a WTRU having a link to a gNB via a RIS to receive UL signals at the gNB and the RIS (e.g., simultaneously).

[0100] The TCI may be configured and reconfigured for a RIS-based system or a RIS-assisted system. The WTRU may be configured and / or reconfigured with a TCI state, for example based on the type of RIS serving the WTRU. The RIS serving the WTRU may assist a communication link with the WTRU (e.g., a RIS operating in a serving cell of the WTRU). The RIS may be passive, semi-active, hybrid, or active. A passive RIS may refer to an implementation without a reflection amplifier for (e.g., all) unit cells (e.g., or antenna elements). A hybrid or semi-active RIS may correspond to a RIS with one or more unit cells utilizing a reflection amplifier, which may provide control over the amplitude response. An active RIS may refer to (e.g., all) unit cells having a reflection amplifier.

[0101] For example, based on the RIS type and / or RIS operation mode of the RIS serving the WTRU, the WTRU may be configured and / or reconfigured with a TCI state. RIS operation (e.g., in terms of the effect on the impinging RF signal) may include, for example, one or more of the following (e.g., in any combination): reflection, refraction, focusing, collimation, absorption, and / or focus. 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.

[0102] 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). RS resources may be resources for CSI-RS, TRS, SSB, etc. For example, the RIS may be capable of reflecting multiple beams simultaneously. The RIS may be made of a (e.g., large) array of passive scattering elements, which may be referred to as unit cells. (Each) unit cell may be configured (e.g., by a network) to achieve one or more of desired signal reflection, refraction, focusing, collimation, absorption, etc.

[0103] 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 TCI state and the corresponding association with the RIS operation mode). The RIS operation modes may include, for example, a reflective RIS, a transmit RIS, a receive RIS, a simultaneous transmit and reflective RIS, a simultaneous reflective and sensing RIS, an amplified RIS, etc. For example, a simultaneous transmit and reflective RIS (e.g., an operation mode) may enable a reconfigurable wireless environment with 360-degree coverage. A simultaneous reflective and sensing RIS may simultaneously reflect an impinging signal (e.g., in a programmable manner), and the impinging signal may be fed to a sensing unit (e.g., at the same time, simultaneously, concurrently).

[0104] A CSI-RS resource may be associated with a RIS. A CSI-RS resource may be configured and / or used to reflect a beam at the RIS. A CSI-RS resource associated with a RIS may be used to transmit a beam at the RIS (e.g., if the RIS is capable of transmitting a beam). A CSI-RS resource associated with a RIS may be used to simultaneously transmit and reflect a beam at the RIS (e.g., if the RIS is capable of simultaneously reflecting a beam and transmitting a beam). There may be multiple (e.g., two) beams generated from a single beam (e.g., between a gNB and a RIS). The resulting / emerging beams may be referred to as reflected beams and transmitted beams (e.g., between a RIS and a WTRU). A first WTRU may measure the CSI-RS and report the beam (e.g., the first layer reference signal received power (L1-RSRP) for the CSI-RS resource). A second WTRU may (e.g., also) measure the same CSI-RS and report the same beam. The gNB may configure the WTRU to have the same TCI state. The gNB may activate the TCI state (e.g., if / when needed). For example, if / when the gNB sends data to the WTRU, the gNB may indicate the TCI state for the WTRU to receive the PDSCH. The gNB may (e.g., also) send data to another (e.g., second) WTRU. The gNB may indicate the TCI state for another (e.g., second) WTRU to (e.g., also) receive the PDSCH. The gNB may allocate different frequency resources to different WTRUs to receive the PDSCH using the same TCI state for both the reflection beam and the transmit beam.

[0105] A (e.g., first) WTRU may measure a (e.g., first) CSI-RS and report a (e.g., first) beam, while another (e.g., second) WTRU may measure a different (e.g., second) CSI-RS and report another (e.g., second) beam. The gNB may configure the (e.g., first and second) WTRUs to have different TCI states. The gNB may activate different TCI states (e.g., if / when needed). For example, if / when the gNB sends data to the (e.g., first) WTRU, the gNB may indicate the (e.g., first) WTRU to receive the (e.g., first) TCI state of the PDSCH. The gNB may (e.g., also) send data to another (e.g., second) WTRU. The gNB may indicate another (e.g., second) WTRU to receive another (e.g., second) TCI state of the PDSCH. The gNB may allocate different frequency resources to the (e.g., first and second) WTRUs to receive the PDSCH using different TCI states for reflection beams and transmit beams.

[0106] CSI-RS resources associated with the gNB may not be used for the RIS. TCI states associated with a RIS (e.g., operating in absorption mode) may not be configured for the WTRU (e.g., because the beam may not be received by the WTRU). CSI-RS resources associated with the RIS may be used for the RIS, which may operate in simultaneous reflection and sensing modes. For example, depending on the RIS operating mode, a TCI state may be associated with the RIS and / or may be configured for the WTRU.

[0107] Figure 3 An example of a RIS configured as a reflection RIS based on a RIS operation mode for beam reflection only is shown. The WTRU may be configured with a TCI state associated with the gNB. The WTRU may be configured with an additional TCI state associated with the RIS for operation / operation mode (e.g., reflection beam only).

[0108] Figure 4 An example of a RIS configured as a reflect and transmit RIS based on a RIS operation mode for simultaneous reflection and transmission is shown. The WTRU may be configured with a TCI state associated with the gNB. The WTRU may be configured with a TCI state associated with the RIS for an operation mode with reflection beams. For example, if the RIS is capable of (e.g., and is configured for) transmit beams, the WTRU may (e.g., also) be configured with (e.g., additional) TCI states associated with the RIS for an operation mode with transmit beams.

[0109] A CSI-RS resource set may be configured for the RIS. A beam may be repeated for a link between a gNB / TRP and a RIS (e.g., a gNB-RIS link), for example, for a CSI-RS resource within a CSI-RS resource set. For example, beam repetition may be indicated to the RIS so that the RIS knows to repeat the same beam on a CSI-RS resource within a CSI-RS resource set for a link between the gNB / TRP and the RIS. Beam repetition and / or repetition indication may be used for beam management or beam scanning for a RIS assisted system. A repetition indicator for a CSI-RS resource may be transmitted to the RIS to manage beams for a link between the gNB / TRP and the RIS. For a link between a RIS and a WTRU (e.g., a RIS-WTRU link), a beam may or may not be repeated. Beam scanning may be performed (e.g., alternatively) for a link between the RIS and the WTRU. For example, if a reflection beam and a transmit beam are coupled, the RIS and the WTRU may be configured with the same CSI-RS resource set for the reflection beam and the transmit beam. The RIS may reflect the same beam towards different directions. The RIS may transmit the same beam in different directions simultaneously. Different beams may be reflected and transmitted on CSI-RS resources within the same CSI-RS resource set for the RIS-WTRU link.

[0110] For example, if the reflected beam and the transmit beam are not coupled, different CSI-RS resource sets for the reflected beam and the transmit beam may be configured for the RIS and WTRU. The same beam may be repeated on CSI-RS resources within the CSI-RS resource set for the gNB-RIS link. Different beams may be reflected and transmitted on CSI-RS resources within different CSI-RS resource sets for the RIS-WTRU link.

[0111] Figure 5 An example of a TCI configuration for a RIS configured for simultaneous reflection and transmission is shown. Figure 5 As shown in the example in , the WTRU may be configured with a primary TCI state associated with the gNB / TRP. The WTRU may be configured with a (e.g., additional / secondary) TCI state associated with the RIS. For example, the WTRU may be configured with an additional / secondary TCI state associated with a RIS that performs beam reflection (e.g., if the RIS operates in reflection mode). The WTRU may be configured with an additional / secondary TCI state associated with a RIS that performs beam transmission (e.g., if the RIS operates in transmission mode).

[0112] The association between RIS type and RIS operation mode may be utilized, for example, by the gNB / TRP. Information used for the association between RIS type and RIS operation mode may 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., unavailable) for other RIS types. For example, a RIS operation mode with a reflective RIS may 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 may 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, while other RIS operation modes may be associated with other RIS types.

[0113] Figure 6 An example method for a mixed RIS TCI configuration of RIS types and RIS operating modes is shown. Figure 6 As shown, the WTRU may be configured with TCI states, for example, based on the number of RISs. For example, the WTRU may be configured with TCI states for M RISs. The M RISs may be of the same or different types. The WTRU may be configured with TCI states for (e.g., each) RIS type. For example, the WTRU may be configured with TCI states L for each type i. i . The RIS operation mode may be determined by the gNB, for example based on the RIS type. The WTRU may receive an indication of the RIS type and / or RIS mode. The WTRU may be configured or reconfigured for a TCI state, for example depending on the RIS mode. The WTRU may be configured with a TCI state for a RIS reflection mode. The WTRU may be configured with a TCI state for a RIS refraction mode. The WTRU may select a subset of TCI states, for example based on the indicated RIS type / mode. For example, if the RIS absorption mode is determined, indicated or known, the WTRU may select a subset of TCI states based on the indicated RIS mode.

[0114] Figure 7 An example method for a hybrid RIS with multiple RISs having RIS mode switching and TCI reconfiguration is shown. Figure 7As shown, the WTRU may be configured with a TCI state associated with one or more (e.g., several) RISs. Different RISs may have different types and / or different operating modes. For example, the WTRU may be configured with different TCI states associated with each RIS of different types and / or modes. For example, the RIS mode may be determined by the gNB based on the WTRU's feedback. The WTRU's feedback may trigger a RIS mode switch. The WTRU's feedback may include, for example, one or more of the following: WTRU measurements (e.g., reference signal measurements and / or interference measurements / levels), WTRU-recommended RIS operating modes, WTRU-measured interference levels, etc. For example, if the WTRU's feedback triggers a RIS mode switch, the RIS may switch to a different RIS mode (e.g., a RIS reflection, refraction, or absorption mode). The mode switch may depend on the determined RIS mode (e.g., based on the WTRU's feedback). The WTRU may receive an indication of the RIS mode to which the RIS has been switched or changed. The WTRU may be reconfigured with a TCI state based on the determined and changed RIS mode.

[0115] The RIS operation mode may be indicated by, for example, a PDCCH, a group common PDCCH (GC-PDCCH), a MAC CE, RRC signaling, etc. (E.g., each) RIS may be configured with an RNTI (e.g., RIS-RNTI). The same or different RNTIs (e.g., or RIS-RNTI) may be configured to different RISs. For example, if PDCCH is used, the PDCCH may be masked with the RIS-RNTI. The RIS may, for example, decode the PDCCH with the RIS's own RNTI (e.g., RIS-RNTI). For example, if the CRC test is passed, the RIS may obtain downlink control information (DCI) in the PDCCH for the RIS operation mode indicator. The RIS operation mode may be updated, changed, or switched (e.g., individually). Table 1 shows an example RIS operation mode indicator. As shown in Table 1, there may be four RIS operation modes (e.g., for reflection, refraction, absorption, and transmission).

[0116] For example, if GC-PDCCH is used, a group common RNTI based on RIS may be used. The group common RNTI may be configured to the RIS. The RIS may decode the GC-PDCCH, for example, using the group common RNTI (e.g., RIS-GC-RNTI) for the RIS. For example, if the CRC test is passed, the RIS may obtain the DCI in the GC-PDCCH for the RIS operation mode indicator. The RISs in the group (e.g., all RISs) may update, change, or switch their operation modes (e.g., simultaneously).

[0117] Table 1 - Examples of RIS operating mode indicators

[0118]

[0119] CSI-RS resources may be configured to the WTRU for a gNB (e.g., only gNB), a RIS (e.g., only RIS), both gNB and RIS, etc. The WTRU may be configured with a set of CSI-RS resources for a beam from a gNB to the WTRU. The WTRU may be configured with an additional set of CSI-RS resources for a beam from the RIS to the WTRU. For example, if the WTRU is configured with a set of CSI-RS resources for a beam from a gNB to the WTRU / when the WTRU is configured with a set of CSI-RS resources for a beam from a gNB to the WTRU, the CSI-RS resources may not be associated with the RIS. For example, if the WTRU is configured with an additional set of CSI-RS resources for a beam from the RIS to the WTRU / when the WTRU is configured with an additional set of CSI-RS resources for a beam from the RIS to the WTRU, the CSI-RS resources may not be associated with the gNB. The CSI-RS resources may be associated with the RIS (e.g., only RIS). An implementation may use a CSI-RS resource or set of resources for only the RIS. An implementation may use a gNB-only CSI-RS resource or set of resources. The WTRU may (e.g., be capable of) operating in an environment with a gNB deployed with a RIS, for example by partitioning the CSI-RS resources into RIS-only and gNB-only CSI-RS resources. The WTRU may, for example, measure the beam quality (e.g., based on L1-RSRP, L1-SINR, etc.) for the gNB / TRP and / or RIS using the gNB / TRP-only CSI-RS resources and / or the RIS-only CSI-RS resources. The WTRU may report a CSI-RS resource indicator (CRI) to the gNB / TRP. The WTRU may be configured with CSI-RS resources for the gNB / TRP and RIS separately and / or jointly for the gNB / TRP and RIS. The TCI state may be associated with the gNB / TRP and / or RIS.

[0120] The WTRU may be configured with a TCI state associated with a gNB (e.g., only gNB) to, for example, receive PDSCH from a gNB. The WTRU may be configured with an additional TCI state associated with a RIS (e.g., only RIS). The TCI state associated with a gNB (e.g., only gNB) may provide beamforming information for the WTRU to receive PDSCH from the gNB. The TCI state associated with a RIS (e.g., only RIS) may provide beamforming information for the WTRU to receive PDSCH from the RIS.

[0121] The WTRU may be configured with a TCI state associated with a gNB (e.g., only a gNB) to, for example, receive a PDCCH. The WTRU may be configured with an additional TCI state associated with a RIS (e.g., only a RIS). The TCI state associated with a gNB (e.g., only a gNB) may provide the WTRU with beamforming information to receive a PDCCH from the gNB. The TCI state associated with a RIS (e.g., only a RIS) may provide the WTRU with beamforming information to receive a PDCCH from the RIS.

[0122] The WTRU may be configured with a TCI state associated with a gNB (e.g., only gNB) to, for example, send a PUSCH. The WTRU may be configured with an additional TCI state associated with a RIS (e.g., only RIS). The TCI state associated with a gNB (e.g., only gNB) may provide the WTRU with beamforming information to send a PUSCH to the gNB. The TCI state associated with a RIS (e.g., only RIS) may provide the WTRU with beamforming information to send a PUSCH to the RIS.

[0123] Similarly, for sending PUCCH, the WTRU may be configured with a TCI state associated with a gNB (e.g., gNB only). The WTRU may be configured with an additional TCI state associated with a RIS (e.g., RIS only). The TCI state associated with a gNB (e.g., gNB only) may provide the WTRU with beamforming information to send PUCCH to the gNB. The TCI state associated with a RIS (e.g., RIS only) may provide the WTRU with beamforming information to send PUCCH to the RIS.

[0124] For RIS-assisted systems, TCI may be activated and deactivated. TCI may be activated or deactivated based on the RIS operating mode and / or RIS type. For RIS-assisted systems with one or more deployed RISs, TCI activation and deactivation may be implemented. The network (NW) may configure and / or reconfigure the RIS. Before activating the TCI state, the RIS may or may not be activated. For example, if the RIS is activated, the WTRU may monitor RS resources (e.g., CSI-RS resources associated with the RIS). The WTRU may measure signals reflected or transmitted from the RIS. For example, if the RIS is not activated, the WTRU may monitor RS resources (e.g., CSI-RS resources associated with the RIS). The WTRU may not measure signals of an inactive RIS, for example, because an inactive RIS may not reflect or transmit signals. The NW may, for example, activate or deactivate a (e.g., configured) RIS based on demand. The WTRU may or may not be configured with a TCI state for (e.g., each) activated RIS. The WTRU may report the most relevant RIS (e.g., the best M RIS) with a beam quality above a (pre)configured threshold. For example, the beam quality may be measured via the corresponding RS (e.g., CSI-RS) resource using one or more metrics (e.g., L1-RSRP, L1-SINR, etc.). The WTRU may report the RIS ID for the most relevant RIS based on the one or more measurements. The WTRU may report the RIS ID via UL signaling or a channel (e.g., PUCCH, PUSCH, MAC CE, etc.). In some examples, the best beam quality may be the strongest beam RIS or the largest number of beams with reasonably good quality, although not necessarily the strongest beam, etc. The NW may associate the WTRU with one or more RISs, for example, based on reports from the WTRU.

[0125] Figure 8 An example method for TCI activation and deactivation for RIS is shown. Figure 8 As shown, the gNB / TRP may activate the RIS. The WTRU may be associated with the RIS. The WTRU may be configured with a TCI state for the associated RIS. The WTRU may report measurements. TCI states may be activated for the WTRU. One or more TCI states may be indicated among the activated TCI states.

[0126] Fig. 9 An example method for RIS operation of a RIS-based system or a RIS-assisted system is shown. Fig. 9As shown, the gNB / TRP may turn on or activate one or more (e.g., a set or a group or all) RIS deployed in the cell. The WTRU may perform measurements and transmit reports to the gNB / TRP. The gNB / TRP may configure the RIS, for example, using a RIS operating mode and / or operating parameters. The WTRU may perform measurements and reports. One or more (e.g., some) RIS may be deactivated, for example, based on measurements and reports from the WTRU. For a deactivated RIS, the TCI state may be deactivated. For example, if the RIS is deactivated, the TCI state may be automatically deactivated. In some examples, the TCI state may be deactivated separately from the RIS deactivation.

[0127] Fig.10 An example method for TCI activation and deactivation for a RIS-assisted system is shown. Fig.10 As shown, the WTRU may communicate with a specific type of RIS (e.g., the WTRU may send to or receive from a specific type of RIS). The gNB may determine the RIS operation mode based on the RIS type. For example, depending on the RIS operation mode, the TCI state may be activated or deactivated for the WTRU. The WTRU may participate in autonomous WTRU activation / deactivation. The WTRU may activate or deactivate the TCI state, for example, based on the indicated RIS operation mode. For example, if the determined RIS operation mode is the RIS reflection mode, the TCI state may be activated for the WTRU. For example, if the determined RIS operation mode is the RIS refraction mode, the TCI state may be activated for the WTRU. For example, if the determined RIS operation mode is the RIS absorption mode, the TCI state may be deactivated for the WTRU.

[0128] The TCI states of the WTRU may be activated for (e.g., each) active RIS associated with the WTRU. In some examples, there may be many TCI states activated. For example, if there is no RIS associated with the WTRU, a specific (e.g., determined, selected, (pre)configured, indicated) number of TCI states (e.g., eight TCI states) may be activated. For example, if (e.g., one) active RIS is associated with the WTRU, a larger number of TCI states (e.g., 16 TCI states) may 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) may be activated. The number of activated TCI states may increase as the number of associated activated RISs increases.

[0129] A larger payload may be used in the MAC CE for control (e.g., if non-uniform TCI is used), such as for a large number of activated TCI states. The MAC CE payload may be used, for example, to activate TCI states for a control channel such as PDCCH or PUCCH. The increased payload size for TCI activation may (e.g., also) result in higher overhead in the DCI for TCI indication.

[0130] In some examples, there may not be any RIS associated with the WTRU (e.g., in 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 (e.g., one) 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 RIS 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 TCI states may increase as the number of associated activated RIS increases.

[0131] TCI indication and / or updates may be provided for RIS-based systems and RIS-assisted systems. A WTRU may (e.g., be capable of) receiving PDSCH from a gNB and / or a RIS (e.g., in a RIS-assisted system). For example, if the beam quality (e.g., based on L1-RSRP, L1-SINR) from the gNB is above a (pre-)configured threshold, the TCI state may be indicated to the WTRU to receive PDSCH from the gNB. For example, if the beam quality from the gNB is below a (pre-)configured threshold, or if the beam from the gNB is blocked and the beam quality from the RIS is above a (pre-)configured threshold, the TCI state may (e.g., also) be indicated to the WTRU to receive PDSCH from the RIS. For example, if the beam quality from the gNB and the RIS are above a (pre-)configured threshold, the TCI state may be indicated to the WTRU to receive PDSCH from the gNB and the RIS (e.g., to achieve diversity gain for the PDSCH). For example, the TCI state may be indicated to the WTRU via DCI carried in the PDCCH. Beam quality can be based on L1-RSRP, L1-SINR, etc.

[0132] The WTRU may (e.g., be able to) send a PUSCH to the gNB and / or the RIS. For example, if the beam quality for the gNB is above a (pre-)configured threshold, the TCI state may be indicated to the WTRU to send the PUSCH to the gNB. For example, if the beam quality for the gNB is below a (pre-)configured threshold, or if the beam to the gNB is blocked and the beam quality for the RIS is above a (pre-)configured threshold, the TCI state may (e.g., also) be indicated to the WTRU to send the PUSCH to the RIS. For example, if the beam quality for the gNB and the RIS is above a (pre-)configured threshold, the TCI state may be indicated to the WTRU to send the PUSCH to the gNB and the RIS (e.g., to achieve diversity gain for the PUSCH). For example, the TCI state may be indicated to the WTRU via a DCI carried in the PDCCH.

[0133] 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 a MAC CE). For example, if the beam quality from the gNB is above a (pre-)configured threshold, the TCI state may be indicated to the WTRU to receive the PDCCH from the gNB. For example, if the beam quality from the gNB is below a (pre-)configured threshold, or if the beam from the gNB is blocked and the beam quality from the RIS is above a (pre-)configured threshold, the TCI state may (e.g., also) be indicated to the WTRU to receive the PDCCH from the RIS. For example, if the beam quality from the gNB and the RIS are above a (pre-)configured threshold, the TCI state may be indicated to the WTRU to receive the PDCCH from the gNB and the RIS (e.g., to achieve diversity gain for the PDCCH).

[0134] The WTRU may (e.g., is capable of) sending PUCCH to the gNB and / or RIS. The TCI state may be indicated to the WTRU (e.g., via a MAC CE). For example, if the beam quality for the gNB is above a (pre-)configured threshold, the TCI state may be indicated to the WTRU to send PUCCH to the gNB. For example, if the beam quality for the gNB is below a (pre-)configured threshold, or if the beam to the gNB is blocked and the beam quality for the RIS is above a (pre-)configured threshold, the TCI state may also be indicated to the WTRU to send PUCCH to the RIS. For example, if the beam quality for the gNB and the RIS is above a (pre-)configured threshold, the TCI state may be indicated to the WTRU to send PUCCH to the gNB and the RIS (e.g., to achieve diversity gain for the PUCCH).

[0135] The WTRU may indicate the TCI state to the gNB / TRP (e.g., based on WTRU measurements) among the activated TCI states for the RIS to receive PDSCH from the RIS. The WTRU may indicate the TCI state to the gNB / TRP (e.g., based on WTRU measurements) among the activated TCI states for the RIS to receive PDCCH or other DL signals or channels from the RIS, or to send PUCCH, PUSCH, Sounding Reference Signal (SRS), or other UL signals or channels. The WTRU may indicate the TCI state to the gNB / TRP, for example, using PUCCH, PUSCH, MAC CE, etc.

[0136] Fig.11 An example method for indicating and updating TCI for a RIS-assisted system is shown. Fig.11 As shown, the WTRU may receive an indication of a TCI state associated with a gNB. For example, if the beam quality is above a (pre)configured threshold, the WTRU may receive an indication of a TCI state associated with a gNB. For example, if the beam quality is below a (pre)configured threshold, the WTRU may receive an indication of a TCI state associated with a RIS. For example, if the beam quality is above a (pre)configured threshold, the WTRU may receive an indication of a TCI state associated with a RIS. For example, if the beam quality is below a (pre)configured threshold, the WTRU may receive an indication of a TCI state associated with another RIS. The WTRU may receive a PDSCH in a RIS-assisted system using a reference signal (beam) corresponding to the indicated TCI state.

[0137] Fig.12 An example method for TCI indication and updating for a RIS-assisted system is shown. Fig.12 As shown, the WTRU may receive an indication of a TCI state associated with a gNB / TRP. For example, if the beam quality is above a threshold, the WTRU may receive an indication of a TCI state associated with a gNB / TRP. For example, if the beam quality is below a threshold of the gNB / TRP, the WTRU may receive an indication of a TCI state associated with a RIS. For example, if the beam quality is above a threshold of the RIS, the WTRU may receive an indication of a TCI state associated with the RIS. For example, if the beam quality is below a threshold of the RIS, the WTRU may receive an indication of a TCI state associated with another RIS.

[0138] The WTRU may receive different indications, e.g., depending on control or data. For example, the WTRU may receive an indication of TCI via a DCI for a RIS-assisted system (e.g., for data). The WTRU may receive an indication of TCI via a MAC CE for a RIS-assisted system (e.g., for control). The WTRU may perform transmission or reception for a RIS-assisted system (e.g., depending on downlink or uplink, respectively). The WTRU may perform (e.g., for downlink) PDCCH or PDSCH reception using the beam indicated in the TCI state for the RIS-assisted system. The WTRU may perform (e.g., for uplink) PUCCH or PUSCH transmission using the beam indicated in the TCI state for the RIS-assisted system.

[0139] The TCI state may be based on the reflection and transmit beams, for example, for a RIS that performs simultaneous reflection and transmission. In an example, there may be four beams for reflection and another four beams for transmission. For example, if the reflection beam and the transmit beam are coupled, the TCI state may be defined jointly. Table 2 shows an example of TCI states for joint reflection and transmit beams. For example, if the reflection beam and the transmit beam are not coupled, the TCI state may (e.g., also) be defined for reflection and transmit beams. Table 3 shows an example of TCI states for decoupled reflection beams and transmit beams.

[0140] Table 2 - Example of TCI status for combined reflected and transmitted beams

[0141]

[0142] Table 3 - Example of TCI status for decoupled reflected and transmitted beams

[0143]

[0144] TCI states may be defined (e.g., separately) for a reflected beam and a transmitted beam. Table 4 shows an example of a TCI state for a reflected beam. Table 5 shows an example of a TCI state for a transmitted beam. TCI code points may be defined for (e.g., each) TCI state and / or a joint TCI state. Table 6 shows an example of a TCI code point for a joint TCI state for a reflected beam and a transmitted beam.

[0145] In a RIS-assisted system, beam scanning and beam management may be supported (eg, implemented) for multiple / different RIS operation modes and DL and UL transmission and / or reception using RIS.

[0146] Table 4 - Example of TCI status for reflected beam

[0147]

[0148] Table 5 - Example of TCI status for transmit beam

[0149]

[0150] Table 6 - Examples of TCI code points

[0151]

[0152] Fig.13 An example method of TCI indication and update for a RIS-assisted system is shown (e.g., by simultaneous reflection and transmission). A WTRU may receive an indication of the TCI state of a reflection beam associated with a RIS. For example, if the beam quality (e.g., for a source reference signal) is below a (pre-)configured threshold, the WTRU may receive an indication of the TCI state of another reflection beam associated with the same or a different RIS. For example, if the beam quality is below a (pre-)configured threshold, the WTRU may receive an indication of the TCI state of a transmit beam associated with the same or a different RIS. The WTRU may use the beam corresponding to the indicated TCI state for a reflection beam and / or a transmit beam to receive a PDSCH or PDCCH, transmit a PUSCH or PUCCH, etc. The beam quality may be based on a measurement of a source reference signal.

[0153] A larger payload may be used in a MAC CE for control (e.g., control information or control signaling). For example, if (e.g., only if) a non-uniform TCI is used (e.g., for a large number of configured or activated TCI states), a larger payload may be used in a MAC CE for control signaling. For example, if a uniform TCI is used, a larger payload may be used in a MAC CE for control signaling and / or data. A larger payload may be used in a DCI for data. For example, if (e.g., only if) a non-uniform TCI is used, a larger payload may be used in a DCI for data. For example, if a uniform TCI is used, a larger payload may be used in a DCI for control signaling and / or data. A larger payload may be used for TCI states for control signaling, such as PDCCH reception or PUCCH transmission for a RIS-assisted system. A larger payload may be used for TCI states for data, such as PDSCH reception or PUSCH transmission for a RIS-assisted system.

[0154] Fig.14 An example method for PDSCH reception at a WTRU for RIS type and RIS mode based on WTRU feedback is shown. Fig.14As shown, the WTRU may communicate with a specific (e.g., determined, selected, indicated) type of RIS. The WTRU may recommend a RIS mode (e.g., a RIS operating mode). The gNB may determine the RIS mode based on the WTRU's feedback. The gNB may determine and indicate a RIS mode that is different from the recommended RIS mode. For example, if the recommended RIS mode is a reflection mode, beam reflection may be performed at the RIS. The WTRU may receive the PDSCH using a reflected beam from the RIS. For example, if the recommended RIS mode is a refraction mode, beam refraction may be performed at the RIS. The WTRU may receive the PDSCH using a refracted beam from the RIS. For example, if the recommended RIS mode is an absorption mode, beam absorption may be performed at the RIS. For example, if the recommended RIS mode is an absorption mode, beam absorption may be performed at the RIS. For example, if / when receiving the PDSCH, the WTRU may remove an interfering beam.

[0155] Fig.15 An example method of RIS mode switching and TCI indication is shown. Fig.15As shown, the WTRU may perform PDCCH / PDSCH reception and / or PUCCH / PUSCH transmission via the RIS for a RIS-assisted system based on the RIS type and / or RIS operation mode. The WTRU may be configured with RS resources, for example, according to the RIS type and / or RIS operation mode. The WTRU may perform, for example, one or more of the following: receive configuration information with TCI states and / or associations with the RIS based on the RIS type and / or RIS operation mode; activate TCI states for beamforming information in a RIS assisted system (e.g., based on the RIS operation mode); receive TCI indications for beam information received or transmitted via the RIS; decode a PDCCH with a RIS-RNTI or a GC-PDCCH with a RIS-GC-RNTI; receive an indication of a RIS operation mode change or switch; switch TCI states based on the indicated TCI for the new RIS operation mode (e.g., TCI may be indicated with a mode indication, such as via a PDCCH, GC-PDCCH, and / or if the RIS mode has not changed, TCI may not be indicated or updated); deactivate one or more TCI states of beamforming information corresponding to absorption operation based on the RIS absorption mode (e.g., under the condition that the RIS operation mode is the absorption mode, deactivate TCI states associated with other RIS operation modes); use a newly indicated DL associated with the new RIS mode. The RIS mode may include receiving a PDCCH and / or PDSCH via one or more RIS beams using a newly indicated UL TCI associated with a new RIS mode; sending a PUCCH and / or PUSCH via one or more RIS beams using an existing DL TCI, for example, if the RIS mode has not changed; and / or sending a PUCCH and / or PUSCH via one or more RIS beams using an existing UL TCI for an existing RIS mode, for example, if the RIS mode has not changed.

[0156] RIS on / off information may be provided for efficient interference management of RIS-based systems or RIS-assisted systems. RIS may be turned on or off (e.g., dynamically), for example, by using a group common PDCCH (GC-PDCCH) to control when RIS is on (e.g., operation enabled) and off (e.g., operation disabled). The on / off information may be indicated using the same RNTI and different PDCCH monitoring periodicities or windows for GC-PDCCH. Different RNTIs may be used with the same PDCCH monitoring periodicity and window. RIS may be divided into multiple groups. RIS on / off information may be applied to different RIS groups. A bitmap for on / off information may be used for each RIS group. For example, depending on the group size, different bitmap sizes may be used.

[0157] The RIS (e.g., or RIS controller) may decode the GC-PDCCH and / or read the DCI carried in the GC-PDCCH. The WTRU may obtain a control field (e.g., a bitmap) that may indicate the (e.g., each) RIS state in the group (e.g., whether the RIS is on or off). The gNB may configure a RIS group ID. The gNB may configure a RIS ID for (e.g., each individual) RIS in (e.g., each) RIS group. The RIS group ID may be masked with the GC-PDCCH. The RIS may decode the GC-PDCCH, for example, based on a CRC masked with the RIS group ID. For example, if the RIS obtains a control field of a RIS on / off indicator in the DCI / when the RIS obtains a control field of a RIS on / off indicator in the DCI, the RIS may read the RIS ID and / or the associated on / off indicator. For example, if RIS "on" is indicated in the RIS on / off indicator, the RIS may be turned on. For example, if RIS "off" is indicated in the RIS on / off indicator, the RIS may be turned off. For example, PDCCH monitoring may be supported during the OFF period to decode and read the RIS on / off indicator during the RIS OFF period.

[0158] For example, a MAC CE may be used to accommodate a larger number of RISs. For example, if the payload size is large, the GC-PDCCH may not be efficient. The MAC CE may be used to carry a RIS on / off indicator. For example, if the RIS group size is greater than a (pre)configured threshold, the MAC CE may be triggered to indicate the RIS on / off state. For example, if the RIS group size is not greater than a (pre)configured threshold, the GC-PDCCH may be triggered to indicate the RIS on / off state.

[0159] RRC signaling may be used to slowly change the RIS on / off state. For example, GC-PDCCH may be used based on interference conditions. For example, if interference conditions change rapidly, GC-PDCCH may be used. For example, if interference conditions change slowly, RRC signaling may be used. For example, MAC CE may be used to balance the payload size and speed of RIS control. The RIS / RIS controller may act as (e.g., behave as) a WTRU in the control signaling protocol / process.

[0160] Fig.16 An example method of RIS on / off information for efficient interference management is shown. Fig.16As shown, the RIS may be configured with a GC-PDCCH monitoring period. The RIS may read the RIS ID in the DCI carried in the GC-PDCCH. For example, if the decoded RIS ID matches the RIS's own RIS ID, the RIS may continue to read the RIS on / off indicator in the DCI. If the RIS indicator is "on", the RIS may be turned on. If the RIS indicator is "off", the RIS may be turned off. For example, if the decoded RIS ID does not match the RIS's own RIS ID, the RIS may stop reading the RIS on / off indicator in the DCI. The RIS may ignore the RIS on / off indicator and / or discard the control information (for example, if the decoded RIS ID does not match the RIS's own RIS ID).

[0161] Fig.17 An example method of RIS on / off indication via a group RNTI is shown. Fig.17 As shown, the RIS may be configured with a group RNTI and a GC-PDCCH monitoring period. The RIS may decode the GC-PDCCH masked with the group RNTI during the (e.g., configured) monitoring period. For example, if the group RNTI matches, the RIS may (e.g., successfully) decode the GC-PDCCH. The RIS may read the RIS ID of the group in the DCI carried in the GC-PDCCH. For example, if the decoded RIS ID matches the RIS ID of the RIS itself in the group, the RIS may continue to read the RIS on / off indicator in the DCI. If the RIS indicator is "on", the RIS may be turned on. If the RIS indicator is "off", the RIS may be turned off. For example, if the decoded RIS ID does not match the RIS ID of the RIS itself in the group, the RIS may stop reading the RIS on / off indicator in the DCI. 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 in the group).

[0162] On / off mode signaling may (eg also) be used. The RIS may be switched on during certain symbols or time slots etc., which may be valid for eg a certain period of time or until the next indication and / or reconfiguration.

[0163] The NW may turn on the RIS (e.g., put the RIS in an on mode) based on interference measurements. For example, the NW may turn on the RIS based on interference measurement reports from the WTRU. The WTRU may report interference measurements and an indication of the RIS that contributed to the interference. The WTRU may report one or more interference RISs to the NW. For example, if the interference level is high (e.g., if the interference is above a (pre-)configured threshold), the WTRU may report the RIS as an interference RIS. The WTRU may, for example, recommend whether to turn the RIS on or off based on interference measurements. For example, the RIS may be turned off based on the interference level (e.g., if the interference is above a (pre-)configured threshold). For example, if the interference is below a (pre-)configured threshold, the RIS may be turned on (e.g., kept on).

[0164] For example, the interference measurement (e.g., Fig.18 As described above, the RIS operation mode may be switched or changed based on an interference measurement report from one or more WTRUs (e.g., a report indicating an interference level associated with the RIS and / or an interference level associated with the gNB). The WTRU may perform, for example, one or more of the following: measuring interference on primary RS resources for a gNB / transmit-receive point (TRP) in a RIS-assisted system; measuring interference on secondary RS resources for an associated RIS in a RIS-assisted system. For example, if the interference level generated by the RIS is high (e.g., beam quality is above a threshold), the RIS operation mode may be switched or changed from a reflection mode to an absorption mode. For example, if the interference level generated from the RIS is low (e.g., beam quality is below a threshold), the RIS operation mode may be switched or changed to a reflection mode or a transmission mode. Beam quality may be measured, for example, by L1-RSRP, L1-SINR, etc.

[0165] Fig.18 An example method of RIS mode switching and TCI indication based on interference level is shown. Fig.18As shown, the WTRU may receive configuration information with TCI states and / or associations with RIS based on the RIS type and / or 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, such as a gNB). The WTRU may determine (e.g., based on measurements) whether the interference level is above a (pre) configured threshold (e.g., interference threshold). If the interference level is above the threshold (e.g., greater than the threshold), the WTRU may feedback (e.g., report / recommend) an absorption mode (e.g., RIS absorption mode). If the interference is not above the threshold (e.g., below the threshold or less than the threshold), the WTRU may feedback (e.g., report / recommend) one or more other modes (e.g., different from the absorption mode). The WTRU may decode a PDCCH with a RIS-RNTI or a GC-PDCCH with a RIS-GC-RNTI. The WTRU may receive an indication of a RIS operation mode change or switch. If the WTRU receives an indication of a RIS operation mode switch, the WTRU may switch the TCI state (activate / deactivate one or more TCI states) based on the indicated TCI for the new RIS operation mode (e.g., the TCI may be indicated with a mode indication such as via PDCCH, GC-PDCCH, and / or if the RIS mode has not changed, the TCI may not be indicated or updated). If the indicated TCI state corresponds to the RIS absorption mode, the WTRU may deactivate one or more TCI states for beamforming information. The WTRU may receive PDCCH and / or PDSCH via one or more RIS beams using the newly indicated DLTCI associated with the new RIS mode. The WTRU may send PUCCH and / or PUSCH via one or more RIS beams using the newly indicated UL TCI associated with the new RIS mode. If the RIS mode has 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 send PUCCH and / or PUSCH via one or more RIS beams using the existing UL TCI for the existing RIS mode.

[0166] A device (e.g., a wireless transmit / receive unit (WTRU)) may receive a first physical downlink shared channel (PDSCH) transmission using a first transmit 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 base station and the RIS. The device may determine an interference level based on the reference signal measurements. 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.

[0167] Under the condition that the interference level is greater than an interference threshold, the second RIS mode may be determined as an absorption mode. Under the condition that the third RIS mode indicates an 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 following: the reference signal measurement 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 multiple TCI states and corresponding associations with RIS operating modes. The indication of the third RIS mode may be received in a group common physical downlink control channel (GC-PDCCH) transmission.

[0168] A training phase for the RIS may be introduced. For example, if the RIS is turned off, the WTRU may not (e.g., be able to) measure interference from the RIS because the RIS may not function when the RIS is turned off. A training phase may be introduced for interference measurements. For example, the RIS may be turned on periodically or aperiodically. For example, depending on when the RIS is turned on, the CSI-RS resources may be configured for interference measurements. In the example where the RIS is turned on periodically, the RIS may be turned on within a (pre)configured window or duration for interference measurements and may be turned off (e.g., autonomously) after the measurement period. The RIS on / off state may be based on a timer.

[0169] In an example where the RIS is turned on non-periodically, the RIS may be triggered (e.g., by a DCI or MAC CE) to turn on. A (pre)configured window or duration may be used for interference measurement and / or channel measurement. For example, the window or duration may be indicated in a DCI or MAC CE. The WTRU may, for example, perform interference measurements based on the indicated window or duration. The window or duration may, for example, be indicated in a trigger signal during a trigger phase. For example, if the window or duration is not indicated (e.g., in a trigger signal during a trigger phase), the WTRU may perform interference measurements based on a (pre)configured window or duration. The indicated window or duration (e.g., in a trigger signal during a trigger phase) may override a configured or preconfigured window or duration.

[0170] The RIS controller may be turned off. For example, if some functions are allowed when the RIS is turned off and / or partially turned off, the WTRU may perform interference measurements. For example, the RIS controller may be turned off, but the RIS reflector may not be turned off. A partially turned off RIS may, for example, reflect signals according to default settings, which may not be adjusted or updated if the RIS controller is turned off. RIS operating modes and functions may be turned off. For example, if an "on" indicator is received, the RIS may receive signaling from the gNB and respond by turning on operating modes and functions.

[0171] The RIS may be turned on or off at different levels. The RIS may be partially or completely turned on or off in different states. The RIS may turn some functions on, and / or turn other functions off. The RIS may be turned on in some operating modes and / or may be turned off in other operating modes. The RIS may turn a receive mode on, and / or may turn a transmit mode off, or vice versa. The RIS may be turned on for signal or beam reflection and / or may be turned off for signal or beam refraction, or vice versa. The RIS may be turned on for signal or beam transmission, and / or may be turned off for signal or beam reflection or refraction, or vice versa. Some parts of the RIS may be turned on, while other parts of the RIS may be turned off. How the RIS is turned on or off may be determined based on indications received from the gNB / TRP. How the RIS is turned on or off may be determined based on feedback from the WTRU. The RIS may turn itself on or off autonomously. The RIS may turn itself on or off autonomously based on some conditions, measurements, or criteria.

[0172] Hybrid RIS types may be deployed in (e.g., the same) system. The WTRU may be configured with CSI-RS resources or resource sets for interference management. The WTRU may be configured with a RIS type. The WTRU may be configured with an association between a RIS type and / or an RS resource or resource set. The RS resource or resource set may be a CSI-RS resource or resource set, an SSB resource or resource set, etc. The CSI-RS resource or resource set may be a ZP-CSI-RS resource or resource set, an NZP-CSI-RS resource or resource set, a CSI interference measurement (CSI-IM) resource or resource set, etc. Different RIS operations may cause different degrees of interference. For example, if different RIS operations coexist in the same system / when different RIS operations coexist in the same system, interference may become more dynamic. Interference management (IM), measurement and / or reporting may be implemented.

[0173] The beam direction may be changed in the same operating mode, for example, to steer an interfering beam away from the WTRU. For example, the operating mode may be changed / switched from one operating mode to another operating mode to mitigate interference. For example, the RIS may be switched from a reflection mode to an absorption mode. The WTRU may report interference to the gNB / TRP. The WTRU may recommend a RIS operating mode to the gNB. For example, if / when the WTRU measures CSI-RS (e.g., for IM, etc.), the WTRU may report interference corresponding to the CSI-RS (e.g., using a recommended mode).

[0174] Uplink / downlink (UL / DL) TDD configurations may be provided for RIS-assisted systems. In some examples, RIS may use (e.g., require) specific UL / DL TDD configurations. The configuration may depend on the RIS type (e.g., active, semi-active, or passive).

[0175] (e.g., each) WTRU having a link via RIS to gNB may be configured with (e.g., only) a cell-specific UL / DL TDD configuration (e.g., via tdd-UL-DL-ConfigurationCommon). For example, if (e.g., all) WTRUs connected via RIS have the same timeslot configuration for UL / DL transmission, the same UL / DL TDD configuration may be used for RIS links (e.g., RIS to gNB links) independent of the RIS type.

[0176] (e.g., each) WTRU having a link via a RIS to a gNB may be configured with a cell-specific UL / DL TDD configuration (e.g., via tdd-UL-DL-ConfigurationCommon) and / or a WTRU-specific UL / DL TDD configuration (e.g., via tdd-UL-DL-ConfigurationDedicated). The WTRU-specific UL / DL TDD configuration may be used to modify the flexible (e.g., not dedicated to UL or DL) timeslots and symbols signaled by tdd-UL-DL-ConfigurationCommon. For example, if a WTRU connected via a RIS has a different timeslot configuration for UL / DL transmission, a WTRU-specific UL / DL TDD configuration may be used for the RIS (e.g., RIS to gNB link) to accommodate the WTRU-specific UL / DL TDD configuration.

[0177] The gNB may be configured with an UL / DL TDD configuration for RIS where the same UL / DL allocation for flexible slots / symbols may be used for (e.g., all) WTRUs having links to the gNB via RIS (e.g., Symbol=allDownlink or Symbol=allUplink or the same nrofDownlinkSymbols and nrofUplinkSymbols may be in the slot with Symbol=Explicit in tdd-UL-DL-ConfigurationDedicated).

[0178] The gNB may configure the UL / DL TDD configuration for the RIS, for example, using several UL / DL patterns (e.g., in addition to the mandatory mode Mode 1 and / or the optional mode Mode 2, if desired). The patterns may have the same (e.g., or similar) parameters, such as one or more of the following: transmission periodicity, the total number of time slots, the number of downlink and uplink time slots, and / or the number of downlink and uplink symbols. The parameters of (e.g., each) pattern may have the same or different values ​​as the parameters of another pattern. The number of patterns used for the RIS to accommodate a WTRU-specific UL / DL TDD configuration may be determined, for example, based on the number of WTRUs having links to the gNB via the RIS and / or based on the transmission periodicity of (e.g., each) pattern. In some examples, the sum of the periodicities of each pattern (P1+P2+…+PN) may be divided by time (e.g., 20 ms) (e.g., with the first symbol in a numbered radio frame, such as an even-numbered radio frame). These patterns may be cascaded and / or may be repeated (e.g., with the sum of the periodicities of each pattern). For example, the RIS type may be active or semi-active to reflect or absorb signals for the assigned transmit direction. For example, if time slots are allocated separately for UL / DL, transmit signals to / from the WTRU may be absorbed by the RIS.

[0179] 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 that have links with the gNB via the RIS. The gNB may determine an option (e.g., the best option) that applies to some (e.g., most) WTRUs. The gNB may configure the UL / DL TDD configuration for the RIS. The gNB may not configure flexible slots for the WTRUs if the configured UL / DL TDD slots do not meet their requirements. Flexible slots may not be used for UL / DL transmissions for these WTRUs.

[0180] The RIS may not expect tdd-UL-DL-ConfigurationDedicated to indicate a symbol as uplink or downlink if tdd-UL-DL-ConfigurationCommon indicates the symbol as downlink or uplink, respectively.

[0181] Fig.19An example method of UL / DL TDD configuration for RIS is shown. The UL / DL TDD configuration for RIS may be assigned, for example, based on similarity of WTRU-specific UL / DL TDD configurations for WTRUs having links with gNBs via RIS and / or RIS types. For example, if the RIS type is passive, then for UL / DL transmissions, the RIS may not absorb signals from / to the WTRU / gNB. The gNB may determine a TDD configuration option (e.g., an optimal TDD configuration option) for some (e.g., most) WTRUs connected via RIS.

[0182] Timing information may be provided to align transmit and receive boundaries of a RIS-based system or a RIS-assisted system.For example, timing information for aligning transmit may be used, depending on the RIS deployment.

[0183] For example, if the RIS is near (e.g., next to) the gNB, then timing information may not be required. For example, the RIS may be co-located with the gNB to enable massive MIMO transmission based on the RIS.

[0184] The RIS may be remote (e.g., located remote) from the gNB, for example, to improve communication performance for a group of WTRUs and / or to enhance the coverage area of ​​the gNB. For example, if the RIS is located remote from the gNB, the gNB to RIS link may have some latency. For example, a WTRU having a link with a gNB via the RIS (e.g., within a gNB coverage area with or without the RIS) may be affected due to latency on the gNB to RIS link and / or the WTRU to RIS link.

[0185] A gNB to RIS link may be considered (e.g., only a single gNB to RIS link). Timing advance adjustments for WTRUs having a link with the gNB via the RIS may be determined accordingly. The gNB may (e.g., first) estimate the transmit timing alignment of a WTRU having a link with the gNB via the RIS. For example, a WTRU may be in a gNB coverage area without a RIS (e.g., the RIS may be used to enhance communications). The RIS may be used to enhance the coverage area of ​​the gNB. The timing information may be developed, for example, by considering one or more of the following: the duplex mode of the cell, the frequency range, the propagation delay of the gNB to RIS link, and / or any processing delays on the RIS. For example, the gNB may obtain the RIS processing delay as part of a feedback or capability message from the RIS. The gNB may estimate the timing information. The gNB may use the propagation delay information from the WTRU in the gNB coverage area (e.g., without the RIS) to estimate the propagation and processing delays of the RIS by comparing the gNB to WTRU link (e.g., for the WTRU propagation delay) and the gNB to RIS / RIS to WTRU link.

[0186] The gNB may estimate the propagation delay (e.g., for the entire path, such as gNB to RIS, RIS to WTRU) (e.g., during the initial access phase). For example, if the gNB knows the propagation delay from the gNB to the RIS in advance, the propagation delay from the RIS to the WTRU may be estimated. The gNB may align the timing advance offset, for example, based on the gNB estimate of the alignment of the transmit timing of the WTRUs having a link with the gNB via the RIS. There may be a single link between the gNB and the RIS. The gNB may configure the timing advance offset value, for example, based on the highest delay (e.g., propagation and processing) estimate of the WTRU having a link with the gNB.

[0187] Fig. 20 An example of timing advance offset alignment for a RIS-assisted system is shown. Fig. 20 As shown, two WTRUs may be in different locations, each with a link to the gNB via the RIS. The RIS may be located away from the gNB. For example, the gNB may transmit a timing advance offset so that the uplink transmission from the WTRU arrives at the RIS and the gNB simultaneously.

[0188] Fig.21 An example method of using timing information to align the transmit and receive boundaries of a RIS is shown. Fig.21As shown, the gNB may (e.g., first) estimate the propagation delay of the WTRU, the propagation delay of the RIS, and the processing delay at the RIS. The gNB may determine whether the WTRU has a link to the gNB via the RIS. The gNB may (e.g., if the WTRU has a link to the gNB via the RIS) align the timing advance offset value, for example based on (e.g., considering) the highest total delay (e.g., including propagation and processing), such that the RIS and the gNB can receive UL symbol timing simultaneously.

[0189] Although the above features and elements are described in particular combinations, each feature or element may be used alone without the other features and elements of the preferred embodiments, or in various combinations with or without the other features and elements.

[0190] Although the specific implementation described herein may consider 3GPP specific protocols, it should be understood that the specific implementation described herein is not limited to this scenario and may be applicable to other wireless systems. For example, although the solution described herein considers LTE, LTE-A, New Radio (NR) or 5G specific protocols, it should be understood that the solution described herein is not limited to this scenario and is also applicable to other wireless systems. For example, although the system has been described with reference to 3GPP, 5G and / or NR network layers, the envisioned implementation extends to specific implementations beyond the use of specific network layer technologies. Similarly, potential implementations extend to all types of service layer architectures, systems and implementations. The techniques described herein can be applied independently and / or used in combination with other resource configuration techniques.

[0191] 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 (sent via wired and / or wireless connections) and / or computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, read-only memory (ROM), random access memory (RAM), registers, cache memory, semiconductor memory devices, magnetic media (such as, but not limited to, built-in hard disks and removable disks), magneto-optical media, and / or optical media (such as compact disk (CD)-ROM disks and / or digital versatile disks (DVDs)). A processor associated with the software may be used to implement a radio frequency transceiver for a WTRU, a terminal, a base station, an RNC, and / or any host computer.

[0192] It should be understood that the entity that performs the processes described herein can be a logical entity that can be implemented in the form of software (e.g., computer executable instructions) that is stored in the memory of a mobile device, network node, or computer system and executed on its processor. That is, the process can 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 a computer system) that performs the process in question when executed by the processor of the node. It should also be understood that any sending and receiving processes shown in the figure can be performed by the communication circuit of the node under the control of the processor of the node and the computer executable instructions (e.g., software) executed by it.

[0193] The various techniques described herein can be implemented in combination with hardware or software, or in a combination of the two where appropriate. Therefore, the specific implementation and device of the subject matter described herein or some aspects or parts thereof may take the form of program code (e.g., instructions), which is embodied in a tangible medium, which includes any other machine-readable storage medium, wherein when the program code is loaded into a machine (such as a computer) and executed by the machine, the machine becomes a device for practicing the subject matter described herein. In the case where the program code is stored on a medium, it is possible that the program code under consideration is stored on one or more media that jointly perform the action under consideration, that is, the one or more media together contain the code for performing the action, but in the case where there is more than one single medium, it is not required that any particular part of the code 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 (including volatile and non-volatile memory and / or storage elements) readable by the processor, at least one input device, and at least one output device. One or more programs may implement or utilize the process described in conjunction with the subject matter described herein, for example, by using an API, a reusable control, etc. Such programs are preferably implemented in a high-level procedural or object-oriented programming language to communicate with a computer system. However, if desired, the program can be implemented in assembly or machine language. In any case, the language can be a compiled or interpreted language and combined with a hardware implementation.

[0194] Although example embodiments may involve utilizing aspects of the subject matter described herein in the context of one or more stand-alone computing systems, the subject matter described herein is not so limited, but may be implemented in conjunction with any computing environment, such as a network or distributed computing environment. Still further, aspects of the subject matter described herein may be implemented in or across multiple processing chips or devices, and storage may similarly be affected across multiple devices. Such devices may include personal computers, network servers, handheld devices, supercomputers, or computers integrated into other systems, such as automobiles and airplanes.

[0195] In describing the preferred embodiments of the subject matter of the present disclosure as shown in the accompanying drawings, specific terminology is employed for the sake of clarity. However, the claimed subject matter is not intended to be limited to the specific terminology so selected, and it is to be understood that each specific element includes all technical equivalents that operate in a similar manner to achieve a similar purpose.

Claims

1. A wireless transmit / receive unit (WTRU), the wireless transmit / receive unit (WTRU) comprising: A processor, the processor being configured to: receiving a first physical downlink shared channel (PDSCH) transmission using a first transmit configuration indicator (TCI) state associated with a base station and using a second TCI state associated with a first reconfigurable intelligent surface (RIS) mode; performing reference signal measurements associated with the RIS; determining an interference level based on the reference signal measurement; determining a second RIS mode based on the interference level; transmitting a message to the base station, wherein the message indicates the second RIS mode; receiving an indication of a third RIS mode associated with a third TCI state, wherein the third TCI state is associated with the base station; and A second PDSCH transmission is received using the third TCI state.

2. The WTRU of claim 1 , wherein the second RIS mode is determined to be an absorption mode under the condition that the interference level is greater than an interference threshold.

3. The WTRU of claim 1 , wherein the second TCI state associated with the first RIS mode is disabled under the condition that the third RIS mode indicates an absorption mode.

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

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

6. The WTRU of claim 1 , wherein the processor is further configured to receive configuration information, and wherein the configuration information indicates a plurality of TCI states and corresponding associations with RIS operating modes.

7. The WTRU of 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 of claim 1 , wherein the processor being configured to perform the reference signal measurements associated with the RIS comprises: The processor is 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 transmit configuration indicator (TCI) state associated with a base station and using a second TCI state associated with a first reconfigurable intelligent surface (RIS) mode; performing reference signal measurements associated with the RIS; determining an interference level based on the reference signal measurement; determining a second RIS mode based on the interference level; transmitting a message to the base station, wherein the message indicates the second RIS mode; receiving an indication of a third RIS mode associated with a third TCI state, wherein the third TCI state is associated with the base station; and A second PDSCH transmission is received using the third TCI state.

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

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

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

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

14. The method of claim 9, wherein the method further comprises receiving configuration information, and wherein the configuration information indicates a plurality of TCI states and corresponding associations with RIS operating modes.

15. The method of claim 9, wherein performing the reference signal measurements associated with the RIS comprises measuring a reference signal received from the RIS.

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