EP4690541A1

EP4690541A1 - Feedback signaling enhancements for reconfigurable intelligent surfaces

Info

Publication number: EP4690541A1
Application number: EP24703072.9A
Authority: EP
Inventors: Ali Ramadan ALI; Khaled Nafez Rauf ARDAH; Soumya Somasekharan NAMBIAR
Original assignee: Lenovo Singapore Pte Ltd
Current assignee: Lenovo Singapore Pte Ltd
Priority date: 2023-03-24
Filing date: 2024-01-26
Publication date: 2026-02-11
Also published as: GB2642591A; CN120883537A; WO2024127380A1

Abstract

Various aspects of the present disclosure relate to an apparatus for feedback signaling enhancements for reconfigurable intelligent surfaces. The apparatus (e.g., a network entity, a UE) transmits to a reconfigurable intelligent surface (RIS), a first signaling indicating a configuration for feedback associated with side control information (SCI) transmitted to the RIS over a control link (C-link). The apparatus receives, from the RIS, a second signaling indicating feedback information by modulation of the second signaling according to the configuration indicated by the first signaling.

Description

FEEDBACK SIGNALING ENHANCEMENTS FOR RECONFIGURABLE INTELLIGENT SURFACES

RELATED APPLICATION

[0001] This application claims priority to U.S. Provisional Application Serial No. 63/492,102 filed March 24, 2023 entitled “FEEDBACK SIGNALING ENHANCEMENTS FOR RECONFIGURABLE INTELLIGENT SURFACES,” the disclosure of which is incorporated by reference herein in its entirety.

TECHNICAL FIELD

[0002] The present disclosure relates to wireless communications, and more specifically to reconfigurable intelligent surfaces.

BACKGROUND

[0003] A wireless communications system may include one or multiple network communication devices, such as base stations, which may be otherwise known as an eNodeB (eNB), a nextgeneration NodeB (gNB), or other suitable terminology. Each network communication device, such as a base station, may support wireless communications for one or multiple user communication devices, which may be otherwise known as user equipment (UE), or other suitable terminology. The wireless communications system may support wireless communications with one or multiple user communication devices by utilizing resources of the wireless communications system, such as time resources (e.g., symbols, slots, subframes, frames, or the like) or frequency resources (e.g., subcarriers, carriers). Additionally, the wireless communications system may support wireless communications across various radio access technologies including third generation (3G) radio access technology, fourth generation (4G) radio access technology, fifth generation (5G) radio access technology, among other suitable radio access technologies beyond 5G (e.g., sixth generation (6G)).

[0004] In a wireless communication system, reconfigurable intelligent surface (RIS) technology can help improve beamforming and coverage of the system so as to serve UEs that may be affected by blockages or scatterers in the environment. To facilitate this, the RIS can be implemented, for example, as a repeater node to monitor environmental reflections and/or assist improving uplink (UL) and/or downlink (DL) signaling between UEs and other network entities (e.g., base stations) by reflecting the UL and/or DL signaling to mitigate the effect of scatterers and/or blockages in the environment.

SUMMARY

[0005] The present disclosure relates to methods, apparatuses, and systems that support feedback signaling enhancements for reconfigurable intelligent surfaces. By utilizing the described techniques, a RIS controller can transfer information (e.g., at least low-rate information) to other network entities (e.g., base stations, UEs, etc.) by manipulating reflections of UL and/or DL signals at the RIS. For instance, a controlling node (e.g., base station, UE, network entity, etc.) provides the RIS controller with a configuration to implicitly signal data (e.g., low-rate data, acknowledgement or negative acknowledgement (ACK/NACK) feedback, etc.) to the controlling node by manipulating propagation and/or reflection characteristics of other UL and/or DL signals transmitted from and/or to one or more UEs via reflection at the RIS. By utilizing aspects of manipulating reflection characteristics of UL / DL signals to implicitly signal information from the RIS to other network entities, bandwidth gains and reductions in network congestion can be achieved. Furthermore, the RIS can provide feedback to the controlling node without requiring specially reserved UL resources, thereby enabling the network to adapt and/or optimize side-link communications over a control link (C-link) or access link between the RIS and the controlling node, without dedicating UL resources for the RIS to provide feedback (e.g., ACK/NACK, etc.) to the controlling node about the C-link.

[0006] In some implementations of the method and apparatuses described herein, an apparatus, such as a base station, a UE, or other network entity, transmits, to a RIS, a first signaling indicating a configuration for feedback associated with side control information (SCI) transmitted to the RIS over a C-link. The apparatus receives, from the RIS, a second signaling indicating feedback information by modulation of the second signaling according to the configuration indicated by the first signaling. [0007] Some implementations of the method and apparatuses described herein may further include the apparatus is a network entity and the second signaling is a reflected signaling of an UL signal transmitted from one or more UE. The apparatus is a UE and the second signaling is a reflected signaling of a DL signal transmitted from a network entity. The configuration indicated by the first signaling is for hybrid automatic repeat request acknowledgment (HARQ-ACK) feedback of the SCI. The feedback information indicated by the RIS in the second signaling includes ACK/NACK feedback information for the SCI. The apparatus detects the feedback information from the RIS by time domain processing of the second signaling. The apparatus detects the feedback information via envelope detection of a time domain signal corresponding to a portion of the second signaling that includes a cyclic prefix (CP) of one or more orthogonal frequency division multiplexing (OFDM) symbols. The apparatus performs spatial demodulation of the time domain signal to identify a reflection pattern of a plurality of segments of the RIS, the reflection pattern indicative of ACK/NACK encoded bits corresponding to the feedback information. The configuration indicates to the RIS to perform time domain modulation of the second signaling during reflection of the second signaling at the RIS to indicate the feedback information.

[0008] Additionally, the configuration indicates to the RIS to perform time domain index modulation of the second signaling by applying an ON/OFF modulation pattern during reflection of the second signaling at the RIS to indicate ACK/NACK encoded bits corresponding to the feedback information. The configuration indicates to the RIS to perform the time domain index modulation at a time duration when a portion of the second signaling being reflected at the RIS corresponds to a CP of one or more ODFM symbols. The configuration indicates to the RIS to perform the time domain index modulation during: a first time duration, in which a first portion of the second signaling corresponding to a first CP is reflected at the RIS, to indicate the ACK/NACK encoded bits; and a second time duration, in which a second portion of the second signaling corresponding to a second CP is reflected at the RIS, to indicate a repetition of the ACK/NACK encoded bits. The configuration indicates to the RIS to perform the time domain index modulation during: a first time duration, in which a first portion of the second signaling corresponding to a first CP is reflected at the RIS, to indicate a first bit of the ACK/NACK encoded bits; and a second time duration, in which a second portion of the second signaling corresponding to a second CP is reflected at the RIS, to indicate a second bit of the ACK/NACK encoded bits. The configuration indicates to the RIS to perform the time domain index modulation by applying an OFF reflection setting during reflection of a first portion of the second signaling to indicate an ACK/NACK encoded bit value of zero and an ON reflection setting during reflection of a second portion of the second signaling to indicate an ACK/NACK encoded bit value of one.

[0009] Additionally, the feedback information includes a bitstream indicated by modulating a power of reflected portions of the second signaling over time to indicate bit values of bits in the bitstream. The configuration indicates to the RIS to reduce a power of the second signaling during a first time duration to indicate a bit value of zero in the bitstream and to reflect the second signaling without reducing the power during a second time duration to indicate a bit value of one in the bitstream. The configuration indicates to the RIS to perform spatial modulation of a reflection of the second signaling to indicate ACK/NACK encoded bits corresponding to the feedback information. The configuration indicates to the RIS to apply an ON/OFF reflection pattern across a plurality of segments of the RIS during the reflection of the second signaling as an indication of the ACK/NACK encoded bits. The configuration indicates to the RIS to reduce reflection of the second signaling at a first segment of the RIS as an indication of an ACK/NACK encoded bit value of zero and to optimize reflection of the second signaling at a second segment of the RIS as an indication of an ACK/NACK encoded bit value of one.

[0010] In some implementations of the method and apparatuses described herein, an apparatus, such as a RIS, receives a first signaling indicating a configuration for feedback associated with SCI transmitted to the apparatus over a C-link; receives a second signaling; and transmits, as a reflected signaling, the second signaling indicating feedback information by modulating the second signaling according to the configuration indicated by the first signaling.

[0011] Some implementations of the method and apparatuses described herein may further include the reflected signaling is a reflection of an UL signal transmitted from one or more UE. The reflected signaling is a reflection of a DL signal transmitted from a network entity. The configuration indicated by the first signaling is for HARQ-ACK feedback of the SCI. The feedback information includes ACK/NACK feedback information for the SCI. The apparatus performs, based on the configuration, time domain modulation of the second signaling to indicate the feedback information. The apparatus performs, based on the configuration, time domain index modulation of the reflected signaling by applying an ON/OFF modulation pattern during reflection of the second signaling to indicate ACK/NACK encoded bits corresponding to the feedback information. The apparatus performs the time domain index modulation during a time duration when a portion of the second signaling reflected at the apparatus corresponds to a CP of one or more ODFM symbols. The apparatus performs the time domain index modulation during: a first time duration, in which a first portion of the second signaling corresponding to a first CP is reflected at the apparatus, to indicate the ACK/NACK encoded bits; and a second time duration, in which a second portion of the second signaling corresponding to a second CP is reflected at the apparatus, to indicate a repetition of the ACK/NACK encoded bits. The apparatus performs the time domain index modulation during: a first time duration, in which a first portion of the second signaling corresponding to a first CP is reflected at the apparatus, to indicate a first bit of the ACK/NACK encoded bits; and a second time duration, in which a second portion of the second signaling corresponding to a second CP is reflected at the apparatus, to indicate a second bit of the ACK/NACK encoded bits. The apparatus performs the time domain index modulation by applying an OFF reflection setting during reflection of a first portion of the second signaling to indicate an ACK/NACK encoded bit value of zero and an ON reflection setting during reflection of a second portion of the second signaling to indicate an ACK/NACK encoded bit value of one. The feedback information includes a bitstream and the apparatus is to indicate the bitstream in the reflected signaling by modulating a power of reflected portions of the second signaling over time based on bit values of bits in the bitstream. The apparatus reduces, based on the configuration, a power of the reflected signaling during a first time duration to indicate a bit value of zero in the bitstream. The apparatus reflects the second signaling without reducing the power during a second time duration to indicate a bit value of one in the bitstream. The apparatus performs, based on the configuration, spatial modulation of the reflected signaling to indicate ACK/NACK encoded bits corresponding to the feedback information. The apparatus applies, based on the configuration, an ON/OFF reflection pattern across a plurality of segments of the apparatus during reflection of the second signaling to indicate the ACK/NACK encoded bits. The apparatus reduces reflection of the second signaling at a first segment of the plurality of segments to indicate an ACK/NACK encoded bit value of zero. The apparatus optimizes reflection of the second signaling at a second segment of the plurality of segments to indicate an ACK/NACK encoded bit value of one. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] FIG. 1 illustrates an example of a wireless communications system that supports feedback signaling enhancements for reconfigurable intelligent surfaces in accordance with aspects of the present disclosure.

[0013] FIG. 2 illustrates an example RIS feeding back ACK/NACK of SCI by manipulating the propagation of forwarded or reflected signals, which supports feedback signaling enhancements for reconfigurable intelligent surfaces in accordance with aspects of the present disclosure.

[0014] FIG. 3 illustrates an example of an RIS providing ACK/NACK feedback by masking a time domain UL signal according to an ON/OFF modulation when reflecting a portion of the UL signal that corresponds to a CP of an OFDM symbol, which supports feedback signaling enhancements for reconfigurable intelligent surfaces in accordance with aspects of the present disclosure.

[0015] FIG. 4 illustrates an example of an RIS providing ACK/NACK feedback by time domain masking of a UL signal during reflection of CPs of multiple OFDM symbols in the UL signal, which supports feedback signaling enhancements for reconfigurable intelligent surfaces in accordance with aspects of the present disclosure.

[0016] FIG. 5 illustrates an example RIS feeding back ACK/NACK by performing spatial modulation of a UL signal by applying an ON/OFF reflection pattern spatially across a plurality of segments of the RIS, which supports feedback signaling enhancements for reconfigurable intelligent surfaces in accordance with aspects of the present disclosure.

[0017] FIGs. 6 and 7 illustrate an example of a block diagram of devices that supports feedback signaling enhancements for reconfigurable intelligent surfaces in accordance with aspects of the present disclosure.

[0018] FIGs. 8-12 illustrate flowcharts of methods that support feedback signaling enhancements for reconfigurable intelligent surfaces in accordance with aspects of the present disclosure. DETAILED DESCRIPTION

[0019] In a wireless communications system, a RIS can be configured with the help of control information (e.g., via a C-link between the RIS and a network entity) to facilitate efficient signal reflection. This control information may include, for example, on/off settings, time information, and/or spatial information for beamforming. The RIS can feedback information and/or report a measured channel of the control link between the RIS and the network entity. In some scenarios, the RIS and the network entity are expected to be deployed in fixed locations and thus quality of the C- link between the network entity and the RIS controller is assumed to be stable. In other scenarios however, the stability of the C-link may depend on the deployment of the RIS and network entity, configuration parameters of the C-link, and/or channel conditions. For example, mobile blockages and/or scatterers in the environment could lead to C-link signal loss and/or quality reductions. Furthermore, in some scenarios, the RIS may serve multiple UEs simultaneously. In these scenarios, a missed or wrongful detection of side information due to missing or wrong RIS reflections may lead to issues on an access link between the RIS and multiple served UEs.

[0020] One way to enhance the reliability of a C-link is by feeding back ACK/NACK information to the network entity. However, transmitting ACK/NACK or any other UL reports of a RIS mobile termination (RIS-MT) requires reserving UL resources for the RIS-MT (e.g., uplink control information over a physical uplink shared channel (PUSCH) or a physical uplink control channel (PUCCH)) and depends on how dynamic the required feedback is. For example, the overhead of ACK/NACK feedback for SCI typically increases with periodicity of updates to the RIS control information since the RIS-MT needs to send ACK/NACK feedback for each received physical downlink control channel (PDCCH) transmission.

[0021] RISs can be configured with the help of control information (e.g., SCI) from network entities (e.g., base station) to optimize signal reflection by the RIS. In examples, a controlling node (e.g., base station or UE) provides the SCI to the RIS over a C-link or access link or other UL resource. However, in some scenarios, the quality of the C-link or other uplink interface between the RIS and the controlling node is not necessarily stable (e.g., due to deployment conditions, channel conditions, environmental conditions, etc.). Thus, to improve reliability of such control signaling, in some examples, the RIS provides feedback information (e.g., channel measurements, ACK/NACK feedback, etc.) to the controlling node about the SCI or other UL control information transmited to the RIS. However, in some scenarios, providing such feedback and/or other UL communications from the RIS to other network entities by using dedicated UL resources (e.g., in the PUSCH or PUCCH) may result in network congestion and a reduction in UL resources available to other network entities (e.g., UEs, etc.).

[0022] In aspects of feedback signaling enhancements for reconfigurable intelligent surfaces, this disclosure describes details for a RIS to implicitly signal feedback information and/or other information to other network entities (e.g., base station, UE, etc.) by manipulating reflections of other UL and/or DL signals transmited from or to one or more UEs in the network and so as to be reflected by the RIS toward one or more other network entities (e.g., base stations, etc.). By superimposing the data that the RIS wants to send on UL or DL signals reserved for serving other entities (e.g., UEs, etc.) and reflected at the RIS toward their destination, the system advantageously frees UL or DL resources that would otherwise be dedicated for transporting feedback or other information from the RIS.

[0023] In further aspects of feedback signaling enhancements for reconfigurable intelligent surfaces, a configuration is provided for using time domain index modulation to signal data (e.g., ACK/NACK) by masking part of a reflected UL or DL signal with an ON/OFF pattern. For example, the RIS reduces a power of the reflected signal (e.g., OFF reflection seting) to implicitly indicate an ACK/NACK bit value of zero and/or reflects the signal without reducing the power (e.g., ON reflection setting) to implicitly indicate an ACK/NACK bit value of one. In some examples, the RIS selectively chooses portions of the signal to modulate (e.g., portions corresponding to CPs of ODFM symbols, etc.), so as to prevent or reduce the likelihood of interfering with the underlying reflected signaling. In further aspects of feedback signaling enhancements for reconfigurable intelligent surfaces, the RIS provides a repetition of the data that is to be sent from the RIS to the network entity or UE by modulating reflections of multiple OFDM symbols, thereby enabling the RIS to achieve further reliability improvements. In further aspects of feedback signaling enhancements for reconfigurable intelligent surfaces, a configuration is provided for the RIS to use spatial modulation for signaling data (e.g., by applying an ON/OFF pattern across different segments of the RIS). By utilizing the aspects of the present disclosure, the wireless communication system advantageously saves network resources and reduces overhead while also improving the reliability of control signaling between the RIS and other network entities by allowing the RIS to provide feedback about the control signaling to the other network entities.

[0024] Aspects of the present disclosure are described in the context of a wireless communications system. Aspects of the present disclosure are further illustrated and described with reference to device diagrams and flowcharts.

[0025] FIG. 1 illustrates an example of a wireless communications system 100 that supports feedback signaling enhancements for reconfigurable intelligent surfaces in accordance with aspects of the present disclosure. The wireless communications system 100 may include one or more network entities 102, one or more UEs 104, a core network 106, and a packet data network 108. The wireless communications system 100 may support various radio access technologies. In some implementations, the wireless communications system 100 may be a 4G network, such as an LTE network or an LTE- Advanced (LTE-A) network. In some other implementations, the wireless communications system 100 may be a 5G network, such as an NR network. In other implementations, the wireless communications system 100 may be a combination of a 4G network and a 5G network, or other suitable radio access technology including Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20. The wireless communications system 100 may support radio access technologies beyond 5G. Additionally, the wireless communications system 100 may support technologies, such as time division multiple access (TDMA), frequency division multiple access (FDMA), or code division multiple access (CDMA), etc.

[0026] The one or more network entities 102 may be dispersed throughout a geographic region to form the wireless communications system 100. One or more of the network entities 102 described herein may be or include or may be referred to as a network node, a base station, a network element, a radio access network (RAN), a base transceiver station, an access point, a NodeB, an eNodeB (eNB), a next-generation NodeB (gNB), or other suitable terminology. A network entity 102 and a UE 104 may communicate via a communication link 110, which may be a wireless or wired connection. For example, a network entity 102 and a UE 104 may perform wireless communication (e.g., receive signaling, transmit signaling) over a Uu interface. [0027] A network entity 102 may provide a geographic coverage area 112 for which the network entity 102 may support services (e.g., voice, video, packet data, messaging, broadcast, etc.) for one or more UEs 104 within the geographic coverage area 112. For example, a network entity 102 and a UE 104 may support wireless communication of signals related to services (e.g., voice, video, packet data, messaging, broadcast, etc.) according to one or multiple radio access technologies. In some implementations, a network entity 102 may be moveable, for example, a satellite (e.g., a non-terrestrial station (NTS)) associated with a non-terrestrial network. In some implementations, different geographic coverage areas 112 associated with the same or different radio access technologies may overlap, but the different geographic coverage areas 112 may be associated with different network entities 102. Information and signals described herein may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0028] The one or more UEs 104 may be dispersed throughout a geographic region of the wireless communications system 100. A UE 104 may include or may be referred to as a mobile device, a wireless device, a remote device, a remote unit, a handheld device, or a subscriber device, or some other suitable terminology. In some implementations, the UE 104 may be referred to as a unit, a station, a terminal, or a client, among other examples. Additionally, or alternatively, the UE 104 may be referred to as an Internet-of-Things (loT) device, an Internet-of-Everything (loE) device, or machine-type communication (MTC) device, among other examples. In some implementations, a UE 104 may be stationary in the wireless communications system 100. In some other implementations, a UE 104 may be mobile in the wireless communications system 100.

[0029] The one or more UEs 104 may be devices in different forms or having different capabilities. Some examples of UEs 104 are illustrated in FIG. 1. A UE 104 may be capable of communicating with various types of devices, such as the network entities 102, other UEs 104, or network equipment (e.g., the core network 106, the packet data network 108, a relay device, an integrated access and backhaul (IAB) node, or another network equipment), as shown in FIG. 1. Additionally, or alternatively, a UE 104 may support communication with other network entities 102 or UEs 104, which may act as relays in the wireless communications system 100. [0030] A UE 104 may also be able to support wireless communication directly with other UEs 104 over a communication link 114. For example, a UE 104 may support wireless communication directly with another UE 104 over a device-to-device (D2D) communication link. In some implementations, such as vehicle-to-vehicle (V2V) deployments, vehicle-to-everything (V2X) deployments, or cellular-V2X deployments, the communication link 114 may be referred to as a sidelink. For example, a UE 104 may support wireless communication directly with another UE 104 over a PC5 interface.

[0031] A network entity 102 may support communications with the core network 106, or with another network entity 102, or both. For example, a network entity 102 may interface with the core network 106 through one or more backhaul links 116 (e.g., via an SI, N2, N6, or another network interface). The network entities 102 may communicate with each other over the backhaul links 116 (e.g., via an X2, Xn, or another network interface). In some implementations, the network entities 102 may communicate with each other directly (e.g., between the network entities 102). In some other implementations, the network entities 102 may communicate with each other or indirectly (e.g., via the core network 106). In some implementations, one or more network entities 102 may include subcomponents, such as an access network entity, which may be an example of an access node controller (ANC). An ANC may communicate with the one or more UEs 104 through one or more other access network transmission entities, which may be referred to as a radio heads, smart radio heads, or transmission-reception points (TRPs).

[0032] In some implementations, a network entity 102 may be configured in a disaggregated architecture, which may be configured to utilize a protocol stack physically or logically distributed among two or more network entities 102, such as an integrated access backhaul (IAB) network, an open RAN (O-RAN) (e.g., a network configuration sponsored by the O-RAN Alliance), or a virtualized RAN (vRAN) (e.g., a cloud RAN (C-RAN)). For example, a network entity 102 may include one or more of a central unit (CU), a distributed unit (DU), a radio unit (RU), a RAN Intelligent Controller (RIC) (e.g., a Near-Real Time RIC (Near-RT RIC), a Non-Real Time RIC (Non-RT RIC)), a Service Management and Orchestration (SMO) system, or any combination thereof.

[0033] An RU may also be referred to as a radio head, a smart radio head, a remote radio head (RRH), a remote radio unit (RRU), or a transmission reception point (TRP). One or more components of the network entities 102 in a disaggregated RAN architecture may be co-located, or one or more components of the network entities 102 may be located in distributed locations (e.g., separate physical locations). In some implementations, one or more network entities 102 of a disaggregated RAN architecture may be implemented as virtual units (e.g., a virtual CU (VCU), a virtual DU (VDU), a virtual RU (VRU)).

[0034] Split of functionality between a CU, a DU, and an RU may be flexible and may support different functionalities depending upon which functions (e.g., network layer functions, protocol layer functions, baseband functions, radio frequency functions, and any combinations thereof) are performed at a CU, a DU, or an RU. For example, a functional split of a protocol stack may be employed between a CU and a DU such that the CU may support one or more layers of the protocol stack and the DU may support one or more different layers of the protocol stack. In some implementations, the CU may host upper protocol layer (e.g., a layer 3 (L3), a layer 2 (L2)) functionality and signaling (e.g., Radio Resource Control (RRC), service data adaption protocol (SDAP), Packet Data Convergence Protocol (PDCP)). The CU may be connected to one or more DUs or RUs, and the one or more DUs or RUs may host lower protocol layers, such as a layer 1 (LI) (e.g., physical (PHY) layer) or an L2 (e.g., radio link control (RLC) layer, medium access control (MAC) layer) functionality and signaling, and may each be at least partially controlled by the CU.

[0035] Additionally, or alternatively, a functional split of the protocol stack may be employed between a DU and an RU such that the DU may support one or more layers of the protocol stack and the RU may support one or more different layers of the protocol stack. The DU may support one or multiple different cells (e.g., via one or more RUs). In some implementations, a functional split between a CU and a DU, or between a DU and an RU may be within a protocol layer (e.g., some functions for a protocol layer may be performed by one of a CU, a DU, or an RU, while other functions of the protocol layer are performed by a different one of the CU, the DU, or the RU).

[0036] A CU may be functionally split further into CU control plane (CU-CP) and CU user plane (CU-UP) functions. A CU may be connected to one or more DUs via a midhaul communication link (e.g., Fl, Fl-c, Fl-u), and a DU may be connected to one or more RUs via a fronthaul communication link (e.g., open fronthaul (FH) interface). In some implementations, a midhaul communication link or a fronthaul communication link may be implemented in accordance with an interface (e.g., a channel) between layers of a protocol stack supported by respective network entities 102 that are in communication via such communication links.

[0037] The core network 106 may support user authentication, access authorization, tracking, connectivity, and other access, routing, or mobility functions. The core network 106 may be an evolved packet core (EPC), or a 5G core (5GC), which may include a control plane entity that manages access and mobility (e.g., a mobility management entity (MME), an access and mobility management functions (AMF)) and a user plane entity that routes packets or interconnects to external networks (e.g., a serving gateway (S-GW), a Packet Data Network (PDN) gateway (P-GW), or a user plane function (UPF)). In some implementations, the control plane entity may manage non-access stratum (NAS) functions, such as mobility, authentication, and bearer management (e.g., data bearers, signal bearers, etc.) for the one or more UEs 104 served by the one or more network entities 102 associated with the core network 106.

[0038] The core network 106 may communicate with the packet data network 108 over one or more backhaul links 116 (e.g., via an SI, N2, N6, or another network interface). The packet data network 108 may include an application server 118. In some implementations, one or more UEs 104 may communicate with the application server 118. A UE 104 may establish a session (e.g., a protocol data unit (PDU) session, or the like) with the core network 106 via a network entity 102. The core network 106 may route traffic (e.g., control information, data, and the like) between the UE 104 and the application server 118 using the established session (e.g., the established PDU session). The PDU session may be an example of a logical connection between the UE 104 and the core network 106 (e.g., one or more network functions of the core network 106).

[0039] In the wireless communications system 100, the network entities 102 and the UEs 104 may use resources of the wireless communications system 100, such as time resources (e.g., symbols, slots, subframes, frames, or the like) or frequency resources (e.g., subcarriers, carriers) to perform various operations (e.g., wireless communications). In some implementations, the network entities 102 and the UEs 104 may support different resource structures. For example, the network entities 102 and the UEs 104 may support different frame structures. In some implementations, such as in 4G, the network entities 102 and the UEs 104 may support a single frame structure. In some other implementations, such as in 5G and among other suitable radio access technologies, the network entities 102 and the UEs 104 may support various frame structures (i.e., multiple frame structures). The network entities 102 and the UEs 104 may support various frame structures based on one or more numerologies.

[0040] One or more numerologies may be supported in the wireless communications system 100, and a numerology may include a subcarrier spacing and a cyclic prefix. A first numerology (e.g., /4=0) may be associated with a first subcarrier spacing (e.g., 15 kHz) and a normal cyclic prefix. The first numerology (e.g., /r=0) associated with the first subcarrier spacing (e.g., 15 kHz) may utilize one slot per subframe. A second numerology (e.g., /z=l) may be associated with a second subcarrier spacing (e.g., 30 kHz) and a normal cyclic prefix. A third numerology (e.g., /r=2) may be associated with a third subcarrier spacing (e.g., 60 kHz) and a normal cyclic prefix or an extended cyclic prefix. A fourth numerology (e.g., /z=3) may be associated with a fourth subcarrier spacing (e.g., 120 kHz) and a normal cyclic prefix. A fifth numerology (e.g., /r=4) may be associated with a fifth subcarrier spacing (e.g., 240 kHz) and a normal cyclic prefix.

[0041] A time interval of a resource (e.g., a communication resource) may be organized according to frames (also referred to as radio frames). Each frame may have a duration, for example, a 10 millisecond (ms) duration. In some implementations, each frame may include multiple subframes. For example, each frame may include 10 subframes, and each subframe may have a duration, for example, a 1 ms duration. In some implementations, each frame may have the same duration. In some implementations, each subframe of a frame may have the same duration.

[0042] Additionally or alternatively, a time interval of a resource (e.g., a communication resource) may be organized according to slots. For example, a subframe may include a number (e.g., quantity) of slots. Each slot may include a number (e.g., quantity) of symbols (e.g., ODFM symbols). In some implementations, the number (e.g., quantity) of slots for a subframe may depend on a numerology. For a normal cyclic prefix, a slot may include 14 symbols. For an extended cyclic prefix (e.g., applicable for 60 kHz subcarrier spacing), a slot may include 12 symbols. The relationship between the number of symbols per slot, the number of slots per subframe, and the number of slots per frame for a normal cyclic prefix and an extended cyclic prefix may depend on a numerology. It should be understood that reference to a first numerology (e.g., /4=0) associated with a first subcarrier spacing (e.g., 15 kHz) may be used interchangeably between subframes and slots. [0043] In the wireless communications system 100, an electromagnetic (EM) spectrum may be split, based on frequency or wavelength, into various classes, frequency bands, frequency channels, etc. By way of example, the wireless communications system 100 may support one or multiple operating frequency bands, such as frequency range designations FR1 (410 MHz - 7.125 GHz), FR2 (24.25 GHz - 52.6 GHz), FR3 (7.125 GHz - 24.25 GHz), FR4 (52.6 GHz - 114.25 GHz), FR4a or FR4-1 (52.6 GHz - 71 GHz), and FR5 (114.25 GHz - 300 GHz). In some implementations, the network entities 102 and the UEs 104 may perform wireless communications over one or more of the operating frequency bands. In some implementations, FR1 may be used by the network entities 102 and the UEs 104, among other equipment or devices for cellular communications traffic (e.g., control information, data). In some implementations, FR2 may be used by the network entities 102 and the UEs 104, among other equipment or devices for short-range, high data rate capabilities.

[0044] FR1 may be associated with one or multiple numerologies (e.g., at least three numerologies). For example, FR1 may be associated with a first numerology (e.g., /z=0), which includes 15 kHz subcarrier spacing; a second numerology (e.g., /z=l ), which includes 30 kHz subcarrier spacing; and a third numerology (e.g., /r=2), which includes 60 kHz subcarrier spacing. FR2 may be associated with one or multiple numerologies (e.g., at least 2 numerologies). For example, FR2 may be associated with a third numerology (e.g., /r=2), which includes 60 kHz subcarrier spacing; and a fourth numerology (e.g., /r=3), which includes 120 kHz subcarrier spacing.

[0045] According to implementations, one or more of the network entities 102 and the UEs 104 are operable to implement various aspects of feedback signaling enhancements for reconfigurable intelligent surfaces, as described herein. For instance, a network entity 102 (e.g., a base station) communicates to RIS 120 a signaling 122 that includes various information, such as a configuration for feedback associated with SCI. In at least one implementation the signaling 122 includes an SCI transmitted to the RIS 120 over a C-link. The RIS 120 receives the signaling 122 and uses the signaling 122 to modulate reflection characteristics of the RIS 120. Next, a UE 104 transmits a signaling 124 to the RIS 120. In an example, the signaling 124 is a UL signal transmitted from the UE 104 for receipt at the network entity 102 via the RIS 120. The RIS 120 receives the UL signal 124 and transmits a reflected signaling 126 to the network entity 102 that corresponds to a reflection of the UL signal 124. In at least one implementation, the reflected signaling 126 is modulated according to the configuration of the signaling 122 (e.g., SCI) to indicate feedback information (e.g., HARQ-ACK feedback, ACK/NACK feedback, C-link channel measurements, etc.) from the RIS 120 to the network entity 102. In alternate examples, the UE 104 transmits the configuration signaling 122 to the RIS 122 (e.g., over a C-link or an access link), and the RIS 120 reflects a DL signal (not shown) from the network entity 102 to the UE 104 so as to indicate the feedback information in the reflected DL signal.

[0046] With reference to deferring HARQ-ACK, a UE procedure for deferring HARQ-ACK for semi persistent scheduling (SPS) physical downlink shared channel (PDSCH) is described. In examples, if a UE is provided sps-HARQ-Deferral and, after performing one or more procedures to resolve overlapping among PUCCHs and PUSCHs in a first slot (if any), the UE determines a PUCCH resource for a PUCCH transmission with first HARQ-ACK information bits for SPS PDSCH receptions that the UE would report for a first time. In examples, the PUCCH resource: is provided by SPS-PUCCH-AN-List, or by nlPUCCH-AN if SPS-PUCCH-AN-List is not provided; is not cancelled by an overlapping PUCCH or PUSCH transmission of larger priority index; or overlaps with a symbol indicated as downlink by tdd-UL-DL-ConfigurationCommon or tdd-UL-DL- ConfigDedicated, or indicated for a SS/PBCH block by ssb-PositionsInBurst, or belonging to a control resource set (CORESET) associated with a TypeO-PDCCH common search space (CSS) set. [0047] In examples, the UE determines an earliest second slot and, after performing one or more procedures to determine a PUCCH with HARQ-ACK information bits including second HARQ-ACK information bits and then performing one or more procedures to resolve overlapping among PUCCHs and PUSCHs (if any), a PUSCH or a PUCCH in the earliest second slot to multiplex HARQ-ACK information bits that include second HARQ-ACK information bits from the first HARQ-ACK information bits. The second HARQ-ACK information bits correspond to SPS PDSCH configurations with sps-HARQ-Deferral values that are larger than or equal to a time difference, with reference to slots for PUCCH transmissions on the primary cell, between the second slot and the slot of the SPS PDSCH reception (if any).

[0048] In an example, if the UE detects a downlink control information (DCI) format in a PDCCH reception that triggers a PUCCH transmission with a Type-3 HARQ-ACK codebook in a slot, the UE stops the procedure to determine the earliest second slot in the slot. In an example, if the UE is provided a periodic cell switching pattern for PUCCH transmissions by pucch- sSCellPattem, the UE determines the earliest second slot and a corresponding cell based on the periodic cell switching pattern. In an example, if the UE multiplexes the second HARQ-ACK information in a PUSCH, or in a PUCCH using a resource that is not from SPS-PUCCH-AN-List, or from nlPUCCH-AN if SPS-PUCCH-AN-List is not provided, the UE stops the procedure to determine the earliest second slot in the slot. In an example, if the UE multiplexes the second HARQ-ACK information in a first PUCCH using a resource provided by SPS-PUCCH-AN-List, or by nlPUCCH-AN if SPS-PUCCH-AN-List is not provided, of smaller priority index and the UE drops the first PUCCH transmission due to an overlapping with a second PUSCH or PUCCH transmission of larger priority index, the UE stops the procedure to determine the earliest second slot in the slot.

[0049] In an example, if the UE multiplexes the second HARQ-ACK information in a first PUCCH using a resource provided by SPS-PUCCH-AN-List, or by nlPUCCH-AN if SPS-PUCCH- AN-List is not provided, and the PUCCH transmission is not dropped due to an overlapping with a PUSCH or PUCCH transmission of larger priority and does not have any symbol that overlaps with a symbol indicated as downlink by tdd-UL-DL-ConfigurationCommon or tdd-UL-DL- ConfigDedicated, or indicated for a SS/PBCH block by ssb-PositionsInBurst, or belonging to a CORESET associated with a TypeO-PDCCH CSS set, the UE stops the procedure to determine the earliest second slot in the slot.In an example, the second HARQ-ACK information bits are appended in a HARQ-ACK codebook that the UE generates. In an example, if the UE receives a PDSCH providing a transport block (TB) for a same HARQ process as a HARQ-ACK information bit from the second HARQ-ACK information bits prior to transmitting the PUCCH or the PUSCH, the UE does not necessarily include the HARQ-ACK information bit in the HARQ-ACK information bits. In an example, the UE is configured to operate without necessarily receiving both sps-HARQ-Deferral and nrofSlots or pucch-RepetitionNrojSlots for any particular PUCCH resource of same priority.

[0050] In aspects of feedback signaling enhancements for reconfigurable intelligent surfaces, solutions for transferring data between a RIS-MT (e.g., a RIS controller) and a controlling node (e.g., gNB, UE, network entity, etc.) by manipulating reflection of signals during UL and/or DL transmission. In examples, the RIS includes a local controller used to receive and apply control information from the controlling node to a reflective surface of the RIS. [0051] FIG. 2 illustrates an example 200 of a RIS 202 feeding back ACK/NACK of SCI by manipulating the propagation of forwarded or reflected signals 208, which supports feedback signaling enhancements for reconfigurable intelligent surfaces in accordance with aspects of the present disclosure. In some examples, the controller (e.g., RIS-MT 204) is configured to transfer feedback information 212 to the controlling node 102 as shown in FIG. 2.

[0052] In an example, the feedback information 212 includes an acknowledgment of receiving control information (e.g., SCI), which enables the controlling node to retransmit the SCI, for example, in a scenario where the RIS-MT 204 has failed to decode the SCI on the C-link 210. The information can be transmitted to the controlling node 102 using the reflection 208 of the forwarded signal 206. For example, RIS-MT 204 indicates an ACK/NACK bit by masking a CP of the UL signal 206 with an ON/OFF pattern to enable the gNB (e.g., network entity 102) to identify the ACK/NACK bit by simple envelope detection of a time domain signal within the CP in the baseband. Thus, in examples, the system 200 reduces overhead associated with RIS-MT feedback on the C-link 208 and provides fast feedback information to the controlling node 102.

[0053] It is noted that although some examples herein describe data transmitted between a RIS and a controlling node as ACK/NACK information, in alternate or additional examples, the various processes and apparatuses described herein are configured to signal other types of data (e.g., low rate data, bit streams, etc.) from the RIS to one or more other network entities by modulating reflections of UL and/or DL signals at the RIS.

[0054] Aspects of the present disclosure include solutions for transmission of SCI ACK/NACK using time domain index modulation. In examples, a RIS controlling node (e.g., gNB, etc.) configures a RIS controller to send an acknowledgement of decoding SCI signaled to the RIS controller (e.g., in RIS-MT specific DCI). In an example, a configuration can be signaled in an RRC message to the RIS-MT. This message may contain the method of the transmission of the ACK/NACK information, the transmission pattern, and the coding rate to be used to encode the ACK/NACK info. The RIS-MT sends, for example, 1 bit indicating the successful decoding of the SCI in the monitoring occasions of RIS-MT specific PDCCH. The encode bits corresponding to the info ACK/NACK bit is implicitly sent by manipulating the propagation of the UL signal. [0055] FIG. 3 illustrates an example 300 of a signal sequence at a RIS configured to provide ACK/NACK feedback 312 by masking a time domain UL signal according to an ON/OFF modulation reflecting a portion 316 of the UL signal that corresponds to a CP of an OFDM symbol 314, which supports feedback signaling enhancements for reconfigurable intelligent surfaces in accordance with aspects of the present disclosure. In an example, transmission of ACK/NACK 312 can be performed via masking part of a time domain UL signal (e.g., the portion corresponding to CP 316, etc.). In an example, the CP 316 of the UL signal transmitted from one or more UEs can be used to indicate the ACK/NACK 312 encoded bits using index modulation in time by masking the time duration of the CP 316 with ON/OFF reflection. For example, the RIS reflects the UL signal during the ON parts and absorbs the received UL signal. In an example, the RIS configures phases of reflecting elements thereof to reduce or prevent reflection of the signal to a network entity (e.g., base during the OFF configuration of the masking apparatus, as shown in FIG. 3.

[0056] As shown in Figure 3, in examples, a RIS controller, after receiving the SCI 302 and detecting, signals the acknowledgment in the next UL transmission by masking the CP 316 of the transmitted UL from UEs connected via RIS. In some examples, a network entity performs envelope detection on a time domain signal corresponding to the CP before removing it to identify the transmitted ACK/NACK of the side control information transmitted to the RIS-MT previously. In examples, a performance of detecting the ACK/NACK information depends on a timing error of the slot boundary which is a function of the error of the timing advance for UL transmission(s). In examples, the ACK/NACK bit can be represented by applying an ON/OFF pattern during reflection of the CP at the RIS. For instance, a reflection pattern represents the encoded bits of the ACK/NACK. In the example shown, 8 ON/OFF parts are embedded in the CP to represent 8 encoded bits of the ACK/NACK bit. In examples, gNB configures the RIS-MT with the code rate of the ACK/NACK or the number of the encoded bits to be inserted in the index modulation. In examples gNB configures the RIS-MT to apply repetition of the ACK/NACK information. In one implementation, an index modulation in time is repeated for the CPs of multiple OFDM symbols during the UL slot as shown in FIG. 3. In another implementation, encoded bits are spread over the CPs of multiple OFDM symbols, so that each CP represents a single bit. For example, if the bit is 0, the RIS reflection is OFF during the whole CP, and if the bit is 1 , no action is made. In yet another implementation, for 0s the OFF reflection is applied on part of the CP as shown in Figure 3. This arrangement advantageously improves network performance, for example, if the synchronization error between UE and gNB is large.

[0057] FIG. 4 illustrates an example 400 of providing ACK/NACK feedback by time domain masking of a UL signal during reflection of CPs of multiple OFDM symbols 402, 404, 406, 408 in the UL signal, which supports feedback signaling enhancements for reconfigurable intelligent surfaces in accordance with aspects of the present disclosure.

[0058] In the illustrated example, four encoded bits (e.g., ‘0110’) of the ACK/NACK (e.g., code rate: 0.25) are transmitted over four OFDM symbols 402-408, by partially masking CPs associated with values of zero and reflecting CPs associated with bit values of one without masking. In some examples, a same pattern can be repeated during a UL slot (e.g., for each group of four OFDM symbols). In some examples, the ACK/NACK information is signaled by reducing a reflection power in the time domain portions of the UL signal that correspond to CPs to indicate ACK/NACK encoded bit values of zero, and by configuring the RIS to provide optimized or relatively better reflection for portions of the UL signal that include CPs to indicate ACK/NACK encoder bit values of one.

[0059] In an example, the RIS is configured to signal an acknowledgement (ACK) by allowing a CP corresponding to the ACK encoded bit to be reflected without masking (e.g., the CPs of ODFM symbols 404 and 406). In this example, the RIS is configured to signal negative acknowledgement (NACK) by reducing or masking reflections of one or more CPs (belonging to one or more OFDM symbols). For example, the CPs of OFDM symbols 402 and 408 are masked or otherwise configured to operate under additional restrictions. In an example, for NACK, the RIS is configured to reflect the corresponding CP in a time domain UL signal, while for ACK, one or multiple CPs (belonging to multiple OFDM symbols) are fully or partially masked. In some examples, where there are no UL transmission from UEs but SCI transmission are still being transmitted to the RIS-MT, the RIS-MT may be configured to reflect any received signal from the environment (e.g., interfered signals from other gNBs or their UEs) to the gNB and insert the ACK/NACK information by masking the reflected signal.

[0060] FIG. 5 illustrates an example 500 of feeding back ACK/NACK by performing spatial modulation of a UL signal 206 by applying an ON/OFF reflection pattern spatially across a plurality of segments 502, 504, 506, 508 of a RIS 202, which supports feedback signaling enhancements for reconfigurable intelligent surfaces in accordance with aspects of the present disclosure.

[0061] Aspects of the present disclosure include solutions for transmission of SCI ACK/NACK using spatial modulation. In examples, a RIS controlling node (e.g., gNB) configures the RIS controller 204 to send acknowledgment 512 of decoding the SCI signaled to the RIS controller (e.g., signaled in RIS-MT specific DCI). In an example, the configuration can be signaled in an RRC message to the RIS-MT 204. For instance, the message indicates a type of the transmission method for ACK/NACK information, transmission patterns, and coding rate to be used to encode the ACK/NACK info. The RIS-MT 204 sends, for example, one bit that indicates a successful decoding of the SCI in monitoring occasions of RIS-MT specific PDCCH. In this example, the transmission of encoded bits of this raw bit is implicitly performed by manipulating propagation of the UL signal 206 (reflected as reflected signaling 208).

[0062] In an example, transmission of the ACK/NACK information 512 is performed by spatial modulation of the UL signal 206 transmitted from one or more UEs. In an example, the gNB 102 configures RIS 202 with multiple segments 502, 504, 506, 508 that can be configured individually. To signal the ACK/NACK encoded bits, in an example, RIS 202 reflects the UL signal 206 by selecting a first set of RIS segments 502, 504 to be configured with no reflection and other segments 506, 508 to be configured with reflection. In order to avoid reduction of the performance of the reflected UL signal 208 at the gNB 102, in some examples, the ON/OFF pattern of the segments 502, 504, 506, 508 is applied during the CP(s) of the symbols. In an example, the gNB 102 performs spatial modulation detection to identify which segment was OFF and which segment was ON. One simple example of the detection is by estimating an angle of departure or reflection from RIS 202 during a CP and/or to identify from which direction (i.e., from which RIS segment) the reflected signal 208 is arriving.

[0063] In one implementation, the spatial modulation of the reflected signal 208 is repeated when the RIS 202 is reflecting other CPs of multiple OFDM symbols (e.g., during an UL slot). In another implementation, encoded bits are spread over the CPs of multiple OFDM symbols, so that each CP represents a single bit. For example, if RIS segment 502 was identified to be OFF during a CP then a corresponding detected bit is zero, and if RIS segment 506 was identified to be ON during a CP, then the corresponding detected bit is one. The example of FIG. 5 shows an indication of four encoded bits (e.g., ‘1001 ’) of ACK/NACK using ON/OFF pattern of four RIS segments.

[0064] In an alternative implementation, the RIS 202 is controlled by a UE (e.g., in case of shared spectrum). In this implementation, the RIS-MT 204 indicates the ACK/NACK of a C-link between the UE and the RIS-MT (not shown) by manipulating a reflected DL signal transmitted from the gNB to the RIS and reflected from the RIS to the UE. Further, in this implementation, the RIS 202 provides an indication of information (e.g., ACK/NACK) to the UE by masking CPs of the DL OFDM symbols and/or based on spatial modulation of the reflected DL signal by applying an ON/OFF reflection pattern across the RIS segments the segments 502, 504, 506, 508 during reflection of the DL signal.

[0065] FIG. 6 illustrates an example of a block diagram 600 of a device 602 that supports feedback signaling enhancements for reconfigurable intelligent surfaces in accordance with aspects of the present disclosure. The device 602 may be an example of a UE 104 or network entity 102 as described herein. The device 602 may support wireless communication with one or more network entities 102, UEs 104, or any combination thereof. The device 602 may include components for bi-directional communications including components for transmitting and receiving communications, such as a processor 604, a memory 606, a transceiver 608, and an I/O controller 610. These components may be in electronic communication or otherwise coupled

(e.g., operatively, communicatively, functionally, electronically, electrically) via one or more interfaces (e.g., buses).

[0066] The processor 604, the memory 606, the transceiver 608, or various combinations thereof or various components thereof may be examples of means for performing various aspects of the present disclosure as described herein. For example, the processor 604, the memory 606, the transceiver 608, or various combinations or components thereof may support a method for performing one or more of the operations described herein.

[0067] In some implementations, the processor 604, the memory 606, the transceiver 608, or various combinations or components thereof may be implemented in hardware (e.g., in communications management circuitry). The hardware may include a processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, a discrete gate or transistor logic, discrete hardware components, or any combination thereof configured as or otherwise supporting a means for performing the functions described in the present disclosure. In some implementations, the processor 604 and the memory 606 coupled with the processor 604 may be configured to perform one or more of the functions described herein (e.g., executing, by the processor 604, instructions stored in the memory 606).

[0068] For example, the processor 604 may support wireless communication at the device 602 in accordance with examples as disclosed herein. The processor 604 may be configured as or otherwise support a means for transmitting, to a RIS, a first signaling indicating a configuration for feedback associated with SCI transmitted to the RIS over a C-link; and receiving, from the RIS, a second signaling indicating feedback information by modulation of the second signaling according to the configuration indicated by the first signaling.

[0069] Additionally, the processor 604 may be configured as or otherwise support any one or combination of the second signaling is a reflected signaling of an UL signal transmitted from one or more UE. The second signaling is a reflected signaling of a DL signal transmitted from a network entity the configuration indicated by the first signaling is for HARQ-ACK feedback of the SCI. The feedback information indicated by the RIS in the second signaling includes ACK/NACK feedback information for the SCI. Detecting the feedback information from the RIS by time domain processing of the second signaling. The detecting the feedback information is via envelope detection of a time domain signal corresponding to a portion of the second signaling that includes a CP of one or more ODFM symbols. Performing spatial demodulation of the time domain signal to identify a reflection pattern of a plurality of segments of the RIS, the reflection pattern indicative of ACK/NACK encoded bits corresponding to the feedback information. The configuration indicates to the RIS to perform time domain modulation of the second signaling during reflection of the second signaling at the RIS to indicate the feedback information. The configuration indicates to the RIS to perform time domain index modulation of the second signaling by applying an ON/OFF modulation pattern during reflection of the second signaling at the RIS to indicate ACK/NACK encoded bits corresponding to the feedback information. The configuration indicates to the RIS to perform the time domain index modulation at a time duration when a portion of the second signaling being reflected at the RIS corresponds to a CP of one or more ODFM symbols, the configuration indicates to the RIS to perform the time domain index modulation during: a first time duration, in which a first portion of the second signaling corresponding to a first CP is reflected at the RIS, to indicate the ACK/NACK encoded bits; and a second time duration, in which a second portion of the second signaling corresponding to a second CP is reflected at the RIS, to indicate a repetition of the ACK/NACK encoded bits, the configuration indicates to the RIS to perform the time domain index modulation during: a first time duration, in which a first portion of the second signaling corresponding to a first CP is reflected at the RIS, to indicate a first bit of the ACK/NACK encoded bits; and a second time duration, in which a second portion of the second signaling corresponding to a second CP is reflected at the RIS, to indicate a second bit of the ACK/NACK encoded bits. The configuration indicates to the RIS to perform the time domain index modulation by applying an OFF reflection setting during reflection of a first portion of the second signaling to indicate an ACK/NACK encoded bit value of zero and an ON reflection setting during reflection of a second portion of the second signaling to indicate an ACK/NACK encoded bit value of one. The feedback information includes a bitstream indicated by modulating a power of reflected portions of the second signaling over time to indicate bit values of bits in the bitstream. The configuration indicates to the RIS to reduce a power of the second signaling during a first time duration to indicate a bit value of zero in the bitstream and to reflect the second signaling without reducing the power during a second time duration to indicate a bit value of one in the bitstream. The configuration indicates to the RIS to perform spatial modulation of a reflection of the second signaling to indicate ACK/NACK encoded bits corresponding to the feedback information. The configuration indicates to the RIS to apply an ON/OFF reflection pattern across a plurality of segments of the RIS during the reflection of the second signaling as an indication of the ACK/NACK encoded bits. The configuration indicates to the RIS to reduce reflection of the second signaling at a first segment of the RIS as an indication of an ACK/NACK encoded bit value of zero and to optimize reflection of the second signaling at a second segment of the RIS as an indication of an ACK/NACK encoded bit value of one.

[0070] Additionally, or alternatively, the device 602, in accordance with examples as disclosed herein, may include a processor and a memory coupled with the processor, the processor configured to cause the apparatus to: transmit, to a RIS, a first signaling indicating a configuration for feedback associated with SCI transmitted to the RIS over a control link (C-link); and receive, from the RIS, a second signaling indicating feedback information by modulation of the second signaling according to the configuration indicated by the first signaling.

[0071] Additionally, the wireless communication at the device 602 may include any one or combination of the apparatus is a network entity and the second signaling is a reflected signaling of an UL signal transmitted from one or more UE. The apparatus is a UE and the second signaling is a reflected signaling of a DL signal transmitted from a network entity. The configuration indicated by the first signaling is for HARQ-ACK feedback of the SCI. The feedback information indicated by the RIS in the second signaling includes ACK/NACK feedback information for the SCI. The processor configured to cause the apparatus to detect the feedback information from the RIS by time domain processing of the second signaling. The processor configured to cause the apparatus to detect the feedback information via envelope detection of a time domain signal corresponding to a portion of the second signaling that includes a CP of one or more ODFM symbols. The processor configured to cause the apparatus to perform spatial demodulation of the time domain signal to identify a reflection pattern of a plurality of segments of the RIS, the reflection pattern indicative of ACK/NACK encoded bits corresponding to the feedback information. The configuration indicates to the RIS to perform time domain modulation of the second signaling during reflection of the second signaling at the RIS to indicate the feedback information. The configuration indicates to the RIS to perform time domain index modulation of the second signaling by applying an ON/OFF modulation pattern during reflection of the second signaling at the RIS to indicate ACK/NACK encoded bits corresponding to the feedback information. The configuration indicates to the RIS to perform the time domain index modulation at a time duration when a portion of the second signaling being reflected at the RIS corresponds to a CP of one or more ODFM symbols. The configuration indicates to the RIS to perform the time domain index modulation during: a first time duration, in which a first portion of the second signaling corresponding to a first CP is reflected at the RIS, to indicate the ACK/NACK encoded bits; and a second time duration, in which a second portion of the second signaling corresponding to a second CP is reflected at the RIS, to indicate a repetition of the ACK/NACK encoded bits. The configuration indicates to the RIS to perform the time domain index modulation by applying an OFF reflection setting during reflection of a first portion of the second signaling to indicate an ACK/NACK encoded bit value of zero and an ON reflection setting during reflection of a second portion of the second signaling to indicate an ACK/NACK encoded bit value of one. The feedback information includes a bitstream indicated by modulating a power of reflected portions of the second signaling over time to indicate bit values of bits in the bitstream. The configuration indicates to the RIS to reduce a power of the second signaling during a first time duration to indicate a bit value of zero in the bitstream and to reflect the second signaling without reducing the power during a second time duration to indicate a bit value of one in the bitstream. The configuration indicates to the RIS to perform spatial modulation of a reflection of the second signaling to indicate ACK/NACK encoded bits corresponding to the feedback information. The configuration indicates to the RIS to apply an ON/OFF reflection pattern across a plurality of segments of the RIS during the reflection of the second signaling as an indication of the ACK/NACK encoded bits. The configuration indicates to the RIS to reduce reflection of the second signaling at a first segment of the RIS as an indication of an ACK/NACK encoded bit value of zero and to optimize reflection of the second signaling at a second segment of the RIS as an indication of an ACK/NACK encoded bit value of one.

[0072] The processor 604 of the device 602 may support wireless communication in accordance with examples disclosed herein. The processor 604 includes at least one controller coupled with at least one memory, and is configured to or operable to cause the processor to transmit, to a RIS, a first signaling indicating a configuration for feedback associated with SCI transmitted to the RIS over a C-link; and receive, from the RIS, a second signaling indicating feedback information by modulation of the second signaling according to the configuration indicated by the first signaling. The at least one controller coupled with the at least one memory may be further configured to cause the processor 604 to perform various operations described herein, such as operations described with reference to the device 602 and/or a UE 104.

[0073] The processor 604 may include an intelligent hardware device (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof). In some implementations, the processor 604 may be configured to operate a memory array using a memory controller. In some other implementations, a memory controller may be integrated into the processor 604. The processor 604 may be configured to execute computer-readable instructions stored in a memory (e.g., the memory 606) to cause the device 602 to perform various functions of the present disclosure. [0074] The memory 606 may include random access memory (RAM) and read-only memory (ROM). The memory 606 may store computer-readable, computer-executable code including instructions that, when executed by the processor 604 cause the device 602 to perform various functions described herein. The code may be stored in a non-transitory computer-readable medium such as system memory or another type of memory. In some implementations, the code may not be directly executable by the processor 604 but may cause a computer (e.g., when compiled and executed) to perform functions described herein. In some implementations, the memory 606 may include, among other things, a basic I/O system (BIOS) which may control basic hardware or software operation such as the interaction with peripheral components or devices.

[0075] The I/O controller 610 may manage input and output signals for the device 602. The I/O controller 610 may also manage peripherals not integrated into the device 602. In some implementations, the I/O controller 610 may represent a physical connection or port to an external peripheral. In some implementations, the I/O controller 610 may utilize an operating system such as iOS®, ANDROID®, MS-DOS®, MS-WINDOWS®, OS/2®, UNIX®, LINUX®, or another known operating system. In some implementations, the I/O controller 610 may be implemented as part of a processor, such as the processor 604. In some implementations, a user may interact with the device 602 via the I/O controller 610 or via hardware components controlled by the I/O controller 610.

[0076] In some implementations, the device 602 may include a single antenna 612. However, in some other implementations, the device 602 may have more than one antenna 612 (i.e., multiple antennas), including multiple antenna panels or antenna arrays, which may be capable of concurrently transmitting or receiving multiple wireless transmissions. The transceiver 608 may communicate bi-directionally, via the one or more antennas 612, wired, or wireless links as described herein. For example, the transceiver 608 may represent a wireless transceiver and may communicate bi-directionally with another wireless transceiver. The transceiver 608 may also include a modem to modulate the packets, to provide the modulated packets to one or more antennas 612 for transmission, and to demodulate packets received from the one or more antennas 612.

[0077] FIG. 7 illustrates an example of a block diagram 700 of a device 702 that supports feedback signaling enhancements for reconfigurable intelligent surfaces in accordance with aspects of the present disclosure. The device 702 may be an example of a RIS 120 as described herein. The device 702 may support wireless communication with one or more network entities 102, UEs 104, or any combination thereof. The device 702 may include components for bi-directional communications including components for transmitting and receiving communications, such as a processor 704, a memory 706, a transceiver 708, and an I/O controller 710. These components may be in electronic communication or otherwise coupled (e.g., operatively, communicatively, functionally, electronically, electrically) via one or more interfaces (e.g., buses).

[0078] The processor 704, the memory 706, the transceiver 708, or various combinations thereof or various components thereof may be examples of means for performing various aspects of the present disclosure as described herein. For example, the processor 704, the memory 706, the transceiver 708, or various combinations or components thereof may support a method for performing one or more of the operations described herein.

[0079] In some implementations, the processor 704, the memory 706, the transceiver 708, or various combinations or components thereof may be implemented in hardware (e.g., in communications management circuitry). The hardware may include a processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, a discrete gate or transistor logic, discrete hardware components, or any combination thereof configured as or otherwise supporting a means for performing the functions described in the present disclosure. In some implementations, the processor 704 and the memory 706 coupled with the processor 704 may be configured to perform one or more of the functions described herein (e.g., executing, by the processor 704, instructions stored in the memory 706).

[0080] For example, the processor 704 may support wireless communication at the device 702 in accordance with examples as disclosed herein. The processor 704 may be configured as or otherwise support a means for receiving, at a RIS, a first signaling indicating a configuration for feedback associated with SCI transmitted to the RIS over a C-link; receiving a second signaling; and transmitting, as a reflected signaling, the second signaling indicating feedback information by modulating the second signaling according to the configuration indicated by the first signaling. [0081] Additionally, the processor 704 may be configured as or otherwise support any one or combination of the reflected signaling is a reflection of an UL signal transmitted from one or more UE. The reflected signaling is a reflection of a DL signal transmitted from a network entity. The configuration indicated by the first signaling is for HARQ-ACK feedback of the SCI. The feedback information includes ACK/NACK feedback information for the SCI. Performing, based on the configuration, time domain modulation of the second signaling to indicate the feedback information. Performing, based on the configuration, time domain index modulation of the reflected signaling by applying an ON/OFF modulation pattern during reflection of the second signaling to indicate ACK/NACK encoded bits corresponding to the feedback information. The performing the time domain index modulation is during a time duration when a portion of the second signaling reflected at the RIS corresponds to a CP of one or more ODFM symbols, the performing the time domain index modulation is during: a first time duration, in which a first portion of the second signaling corresponding to a first CP is reflected at the RIS, to indicate the ACK/NACK encoded bits; and a second time duration, in which a second portion of the second signaling corresponding to a second CP is reflected at the apparatus, to indicate a repetition of the ACK/NACK encoded bits, the performing the time domain index modulation is during: a first time duration, in which a first portion of the second signaling corresponding to a first CP is reflected at the RIS, to indicate a first bit of the ACK/NACK encoded bits; and a second time duration, in which a second portion of the second signaling corresponding to a second CP is reflected at the apparatus, to indicate a second bit of the ACK/NACK encoded bits, the performing the time domain index modulation includes applying an OFF reflection setting during reflection of a first portion of the second signaling to indicate an ACK/NACK encoded bit value of zero and an ON reflection setting during reflection of a second portion of the second signaling to indicate an ACK/NACK encoded bit value of one. Modulating a power of reflected portions of the second signaling over time based on bit values of bits in a bitstream to indicate the bitstream in the reflected signaling. Reducing, based on the configuration, a power of the reflected signaling during a first time duration to indicate a bit value of zero in the bitstream. Reflecting the second signaling without reducing the power during a second time duration to indicate a bit value of one in the bitstream. Performing, based on the configuration, spatial modulation of the reflected signaling to indicate ACK/NACK encoded bits corresponding to the feedback information. Applying, based on the configuration, an ON/OFF reflection pattern across a plurality of segments of the RIS during reflection of the second signaling to indicate the ACK/NACK encoded bits.

[0082] Additionally, or alternatively, the device 702, in accordance with examples as disclosed herein, may include a processor and a memory coupled with the processor, the processor configured to cause the apparatus to: receive a first signaling indicating a configuration for feedback associated with SCI transmitted to the apparatus over a C-link; receive a second signaling; and transmit, as a reflected signaling, the second signaling indicating feedback information by modulating the second signaling according to the configuration indicated by the first signaling. Reducing reflection of the second signaling at a first segment of the plurality of segments to indicate an ACK/NACK encoded bit value of zero. Optimizing reflection of the second signaling at a second segment of the plurality of segments to indicate an ACK/NACK encoded bit value of one.

[0083] Additionally, the wireless communication at the device 702 may include any one or combination of the reflected signaling is a reflection of an UL signal transmitted from one or more UE. The reflected signaling is a reflection of a DL signal transmitted from a network entity. The configuration indicated by the first signaling is for HARQ-ACK feedback of the SCI. The feedback information includes ACK/NACK feedback information for the SCI. The processor configured to cause the apparatus to perform, based on the configuration, time domain modulation of the second signaling to indicate the feedback information. The processor configured to cause the apparatus to perform, based on the configuration, time domain index modulation of the reflected signaling by applying an ON/OFF modulation pattern during reflection of the second signaling to indicate ACK/NACK encoded bits corresponding to the feedback information. The processor configured to cause the apparatus to perform the time domain index modulation during a time duration when a portion of the second signaling reflected at the apparatus corresponds to a CP of one or more ODFM symbols. The processor configured to cause the apparatus to perform the time domain index modulation during: a first time duration, in which a first portion of the second signaling corresponding to a first CP is reflected at the apparatus, to indicate the ACK/NACK encoded bits; and a second time duration, in which a second portion of the second signaling corresponding to a second CP is reflected at the apparatus, to indicate a repetition of the ACK/NACK encoded bits. The processor configured to cause the apparatus to perform the time domain index modulation during: a first time duration, in which a first portion of the second signaling corresponding to a first CP is reflected at the apparatus, to indicate a first bit of the ACK/NACK encoded bits; and a second time duration, in which a second portion of the second signaling corresponding to a second CP is reflected at the apparatus, to indicate a second bit of the ACK/NACK encoded bits. The processor configured to cause the apparatus to perform the time domain index modulation by applying an OFF reflection setting during reflection of a first portion of the second signaling to indicate an ACK/NACK encoded bit value of zero and an ON reflection setting during reflection of a second portion of the second signaling to indicate an ACK/NACK encoded bit value of one. The feedback information includes a bitstream and the apparatus is to indicate the bitstream in the reflected signaling by modulating a power of reflected portions of the second signaling over time based on bit values of bits in the bitstream. The processor configured to cause the apparatus to reduce, based on the configuration, a power of the reflected signaling during a first time duration to indicate a bit value of zero in the bitstream. The processor configured to cause the apparatus to reflect the second signaling without reducing the power during a second time duration to indicate a bit value of one in the bitstream. The processor configured to cause the apparatus to perform, based on the configuration, spatial modulation of the reflected signaling to indicate ACK/NACK encoded bits corresponding to the feedback information. The processor configured to cause the apparatus to apply, based on the configuration, an ON/OFF reflection pattern across a plurality of segments of the apparatus during reflection of the second signaling to indicate the ACK/NACK encoded bits. The processor configured to cause the apparatus to reduce reflection of the second signaling at a first segment of the plurality of segments to indicate an ACK/NACK encoded bit value of zero. The processor configured to cause the apparatus to optimize reflection of the second signaling at a second segment of the plurality of segments to indicate an ACK/NACK encoded bit value of one.

[0084] The processor 704 may include an intelligent hardware device (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof). In some implementations, the processor 704 may be configured to operate a memory array using a memory controller. In some other implementations, a memory controller may be integrated into the processor 704. The processor 704 may be configured to execute computer-readable instructions stored in a memory (e.g., the memory 706) to cause the device 702 to perform various functions of the present disclosure. [0085] The memory 706 may include random access memory (RAM) and read-only memory (ROM). The memory 706 may store computer-readable, computer-executable code including instructions that, when executed by the processor 704 cause the device 702 to perform various functions described herein. The code may be stored in a non-transitory computer-readable medium such as system memory or another type of memory. In some implementations, the code may not be directly executable by the processor 704 but may cause a computer (e.g., when compiled and executed) to perform functions described herein. In some implementations, the memory 706 may include, among other things, a basic I/O system (BIOS) which may control basic hardware or software operation such as the interaction with peripheral components or devices.

[0086] The I/O controller 710 may manage input and output signals for the device 702. The I/O controller 710 may also manage peripherals not integrated into the device 702. In some implementations, the I/O controller 710 may represent a physical connection or port to an external peripheral. In some implementations, the I/O controller 710 may utilize an operating system such as iOS®, ANDROID®, MS-DOS®, MS-WINDOWS®, OS/2®, UNIX®, LINUX®, or another known operating system. In some implementations, the I/O controller 710 may be implemented as part of a processor, such as the processor 704. In some implementations, a user may interact with the device 702 via the I/O controller 710 or via hardware components controlled by the I/O controller 710.

[0087] In some implementations, the device 702 may include a single antenna 712. However, in some other implementations, the device 702 may have more than one antenna 712 (i.e., multiple antennas), including multiple antenna panels or antenna arrays, which may be capable of concurrently transmitting or receiving multiple wireless transmissions. The transceiver 708 may communicate bi-directionally, via the one or more antennas 712, wired, or wireless links as described herein. For example, the transceiver 708 may represent a wireless transceiver and may communicate bi-directionally with another wireless transceiver. The transceiver 708 may also include a modem to modulate the packets, to provide the modulated packets to one or more antennas 712 for transmission, and to demodulate packets received from the one or more antennas 712.

[0088] FIG. 8 illustrates a flowchart of a method 800 that supports feedback signaling enhancements for reconfigurable intelligent surfaces in accordance with aspects of the present disclosure. The operations of the method 800 may be implemented by a device or its components as described herein. For example, the operations of the method 800 may be performed by a UE 104 or a network entity 102 as described with reference to FIGs. 1 through 7. In some implementations, the device may execute a set of instructions to control the function elements of the device to perform the described functions. Additionally, or alternatively, the device may perform aspects of the described functions using special-purpose hardware.

[0089] At 802, the method may include transmitting, to a RIS, a first signaling indicating a configuration for feedback associated with SCI transmitted to the RIS over a C-link. The operations of 802 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 802 may be performed by a device as described with reference to FIG. 1.

[0090] At 804, the method may include receiving, from the RIS, a second signaling indicating feedback information by modulation of the second signaling according to the configuration indicated by the first signaling. The operations of 804 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 804 may be performed by a device as described with reference to FIG. 1.

[0091] FIG. 9 illustrates a flowchart of a method 900 that supports feedback signaling enhancements for reconfigurable intelligent surfaces in accordance with aspects of the present disclosure. The operations of the method 900 may be implemented by a device or its components as described herein. For example, the operations of the method 900 may be performed by a UE 104 or a network entity 102 as described with reference to FIGs. 1 through 7. In some implementations, the device may execute a set of instructions to control the function elements of the device to perform the described functions. Additionally, or alternatively, the device may perform aspects of the described functions using special-purpose hardware.

[0092] At 902, the method may include detecting the feedback information from the RIS by time domain processing of the second signaling. The operations of 902 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 902 may be performed by a device as described with reference to FIG. 1. [0093] At 904, the method may include detecting the feedback information via envelope detection of a time domain signal corresponding to a portion of the second signaling that includes a CP of one or more ODFM symbols. The operations of 904 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 904 may be performed by a device as described with reference to FIG. 1.

[0094] At 906, the method may include performing spatial demodulation of the time domain signal to identify a reflection pattern of a plurality of segments of the RIS, the reflection pattern indicative of ACK/NACK encoded bits corresponding to the feedback information. The operations of 906 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 906 may be performed by a device as described with reference to FIG. 1.

[0095] FIG. 10 illustrates a flowchart of a method 1000 that supports feedback signaling enhancements for reconfigurable intelligent surfaces in accordance with aspects of the present disclosure. The operations of the method 1000 may be implemented by a device or its components as described herein. For example, the operations of the method 1000 may be performed by a RIS 120 as described with reference to FIGs. 1 through 7. In some implementations, the device may execute a set of instructions to control the function elements of the device to perform the described functions. Additionally, or alternatively, the device may perform aspects of the described functions using special-purpose hardware.

[0096] At 1002, the method may include receiving, at a RIS, a first signaling indicating a configuration for feedback associated with SCI transmitted to the RIS over a C-link. The operations of 1002 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 1002 may be performed by a device as described with reference to FIG. 1.

[0097] At 1004, the method may include receiving a second signaling. The operations of 1004 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 1004 may be performed by a device as described with reference to FIG. 1. [0098] At 1006, the method may include transmitting, as a reflected signaling, the second signaling indicating feedback information by modulating the second signaling according to the configuration indicated by the first signaling. The operations of 1006 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 1006 may be performed by a device as described with reference to FIG. 1.

[0099] FIG. 11 illustrates a flowchart of a method 1100 that supports feedback signaling enhancements for reconfigurable intelligent surfaces in accordance with aspects of the present disclosure. The operations of the method 1100 may be implemented by a device or its components as described herein. For example, the operations of the method 1100 may be performed by a RIS 120 as described with reference to FIGs. 1 through 7. In some implementations, the device may execute a set of instructions to control the function elements of the device to perform the described functions. Additionally, or alternatively, the device may perform aspects of the described functions using special-purpose hardware.

[0100] At 1102, the method may include performing, based on the configuration, time domain modulation of the second signaling to indicate the feedback information. The operations of 1102 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 1102 may be performed by a device as described with reference to FIG. 1.

[0101] At 1104, the method may include performing, based on the configuration, time domain index modulation of the reflected signaling by applying an ON/OFF modulation pattern during reflection of the second signaling to indicate ACK/NACK encoded bits corresponding to the feedback information. The operations of 1104 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 1104 may be performed by a device as described with reference to FIG. 1.

[0102] At 1106, the method may include modulating a power of reflected portions of the second signaling over time based on bit values of bits in a bitstream to indicate the bitstream in the reflected signaling. The operations of 1106 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 1106 may be performed by a device as described with reference to FIG. 1. [0103] At 1108, the method may include reducing, based on the configuration, a power of the reflected signaling during a first time duration to indicate a bit value of zero in the bitstream. The operations of 1108 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 1108 may be performed by a device as described with reference to FIG. 1.

[0104] At 1110, the method may include reflecting the second signaling without reducing the power during a second time duration to indicate a bit value of one in the bitstream. The operations of 1110 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 1110 may be performed by a device as described with reference to FIG. 1.

[0105] FIG. 12 illustrates a flowchart of a method 1200 that supports feedback signaling enhancements for reconfigurable intelligent surfaces in accordance with aspects of the present disclosure. The operations of the method 1200 may be implemented by a device or its components as described herein. For example, the operations of the method 1200 may be performed by a RIS 120 as described with reference to FIGs. 1 through 7. In some implementations, the device may execute a set of instructions to control the function elements of the device to perform the described functions. Additionally, or alternatively, the device may perform aspects of the described functions using special-purpose hardware.

[0106] At 1202, the method may include performing, based on the configuration, spatial modulation of the reflected signaling to indicate ACK/NACK encoded bits corresponding to the feedback information. The operations of 1202 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 1202 may be performed by a device as described with reference to FIG. 1.

[0107] At 1204, the method may include applying, based on the configuration, an ON/OFF reflection pattern across a plurality of segments of the RIS during reflection of the second signaling to indicate the ACK/NACK encoded bits. The operations of 1204 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 1204 may be performed by a device as described with reference to FIG. 1. [0108] At 1206, the method may include reducing reflection of the second signaling at a first segment of the plurality of segments to indicate an ACK/NACK encoded bit value of zero. The operations of 1206 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 1206 may be performed by a device as described with reference to FIG. 1.

[0109] At 1208, the method may include optimizing reflection of the second signaling at a second segment of the plurality of segments to indicate an ACK/NACK encoded bit value of one. The operations of 1208 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 1208 may be performed by a device as described with reference to FIG. 1.

[0110] It should be noted that the methods described herein describe possible implementations, and that the operations and the steps may be rearranged or otherwise modified and that other implementations are possible. Further, aspects from two or more of the methods may be combined.

[0111] The various illustrative blocks and components described in connection with the disclosure herein may be implemented or performed with a general-purpose processor, a DSP, an ASIC, a CPU, an FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0112] The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Other examples and implementations are within the scope of the disclosure and appended claims. For example, due to the nature of software, functions described herein may be implemented using software executed by a processor, hardware, firmware, hardwiring, or combinations of any of these. Features implementing functions may also be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations.

[0113] Computer-readable media includes both non-transitory computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A non-transitory storage medium may be any available medium that may be accessed by a general-purpose or special-purpose computer. By way of example, and not limitation, non-transitory computer-readable media may include RAM, ROM, electrically erasable programmable ROM (EEPROM), flash memory, compact disk (CD) ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other non-transitory medium that may be used to carry or store desired program code means in the form of instructions or data structures and that may be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor.

[0114] Any connection may be properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of computer-readable medium. Disk and disc, as used herein, include CD, laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above are also included within the scope of computer-readable media.

[0115] As used herein, including in the claims, “or” as used in a list of items (e.g., a list of items prefaced by a phrase such as “at least one of’ or “one or more of’ or “one or both of’) indicates an inclusive list such that, for example, a list of at least one of A, B, or C means A or B or C or AB or AC or BC or ABC (i.e., A and B and C). Similarly, a list of one or more of A, B, or C means A or B or C or AB or AC or BC or ABC (i.e., A and B and C). Also, as used herein, the phrase “based on” shall not be construed as a reference to a closed set of conditions. For example, an example step that is described as “based on condition A” may be based on both a condition A and a condition B without departing from the scope of the present disclosure. In other words, as used herein, the phrase “based on” shall be construed in the same manner as the phrase “based at least in part on”. Further, as used herein, including in the claims, a “set” may include one or more elements.

[0116] The terms “transmitting,” “receiving,” or “communicating,” when referring to a network entity, may refer to any portion of a network entity (e.g., a base station, a CU, a DU, a RU) of a RAN communicating with another device (e.g., directly or via one or more other network entities).

[0117] The description set forth herein, in connection with the appended drawings, describes example configurations and does not represent all the examples that may be implemented or that are within the scope of the claims. The term “example” used herein means “serving as an example, instance, or illustration,” and not “preferred” or “advantageous over other examples.” The detailed description includes specific details for the purpose of providing an understanding of the described techniques. These techniques, however, may be practiced without these specific details. In some instances, known structures and devices are shown in block diagram form to avoid obscuring the concepts of the described example.

[0118] The description herein is provided to enable a person having ordinary skill in the art to make or use the disclosure. Various modifications to the disclosure will be apparent to a person having ordinary skill in the art, and the generic principles defined herein may be applied to other variations without departing from the scope of the disclosure. Thus, the disclosure is not limited to the examples and designs described herein but is to be accorded the broadest scope consistent with the principles and novel features disclosed herein.

Claims

CLAIMS What is claimed is:

1. An apparatus for wireless communication, comprising: at least one memory; and at least one processor coupled with the at least one memory and configured to cause the apparatus to: transmit, to a reconfigurable intelligent surface (RIS), a first signaling indicating a configuration for feedback associated with side control information (SCI) transmitted to the RIS over a control link (C-link); and receive, from the RIS, a second signaling indicating feedback information by modulation of the second signaling according to the configuration indicated by the first signaling.

2. The apparatus of claim 1 , wherein the apparatus is a network entity and the second signaling is a reflected signaling of an uplink (UL) signal transmitted from one or more user equipment (UE).

3. The apparatus of claim 1 , wherein the apparatus is a user equipment (UE) and the second signaling is a reflected signaling of a downlink (DL) signal transmitted from a network entity.

4. The apparatus of claim 1 , wherein: the configuration indicated by the first signaling is for hybrid automatic repeat request acknowledgment (HARQ-ACK) feedback of the SCI; and the feedback information indicated by the RIS in the second signaling includes acknowledgement or negative acknowledgement (ACK/NACK) feedback information for the SCI.

5. The apparatus of claim 1 , wherein the at least one processor is configured to cause the apparatus to at least one of: detect the feedback information from the RIS by time domain processing of the second signaling; or detect the feedback information via envelope detection of a time domain signal corresponding to a portion of the second signaling that includes a cyclic prefix (CP) of one or more orthogonal frequency division multiplexing (OFDM) symbols.

6. The apparatus of claim 5, wherein the at least one processor is configured to cause the apparatus to: perform spatial demodulation of the time domain signal to identify a reflection pattern of a plurality of segments of the RIS, the reflection pattern indicative of acknowledgement or negative acknowledgement (ACK/NACK) encoded bits corresponding to the feedback information.

7. The apparatus of claim 1 , wherein the configuration indicates to the RIS to perform time domain modulation of the second signaling during reflection of the second signaling at the RIS to indicate the feedback information.

8. The apparatus of claim 1 , wherein the configuration indicates to the RIS to perform time domain index modulation of the second signaling by applying an ON/OFF modulation pattern during reflection of the second signaling at the RIS to indicate acknowledgment or negative acknowledgement (ACK/NACK) encoded bits corresponding to the feedback information.

9. The apparatus of claim 8, wherein the configuration indicates to the RIS to perform the time domain index modulation at a time duration when a portion of the second signaling being reflected at the RIS corresponds to a cyclic prefix (CP) of one or more orthogonal frequency division multiplexing (OFDM) symbols.

10. The apparatus of claim 9, wherein the configuration indicates to the RIS to perform the time domain index modulation during: a first time duration, in which a first portion of the second signaling corresponding to a first CP is reflected at the RIS, to indicate the ACK/NACK encoded bits; and a second time duration, in which a second portion of the second signaling corresponding to a second CP is reflected at the RIS, to indicate a repetition of the ACK/NACK encoded bits.

11. The apparatus of claim 9, wherein the configuration indicates to the RIS to perform the time domain index modulation during: a first time duration, in which a first portion of the second signaling corresponding to a first CP is reflected at the RIS, to indicate a first bit of the ACK/NACK encoded bits; and a second time duration, in which a second portion of the second signaling corresponding to a second CP is reflected at the RIS, to indicate a second bit of the ACK/NACK encoded bits.

12. The apparatus of claim 8, wherein the configuration indicates to the RIS to perform the time domain index modulation by applying an OFF reflection setting during reflection of a first portion of the second signaling to indicate an ACK/NACK encoded bit value of zero and an ON reflection setting during reflection of a second portion of the second signaling to indicate an ACK/NACK encoded bit value of one.

13. The apparatus of claim 1, wherein the feedback information includes a bitstream indicated by modulating a power of reflected portions of the second signaling over time to indicate bit values of bits in the bitstream.

14. The apparatus of claim 13, wherein the configuration indicates to the RIS to reduce a power of the second signaling during a first time duration to indicate a bit value of zero in the bitstream and to reflect the second signaling without reducing the power during a second time duration to indicate a bit value of one in the bitstream.

15. The apparatus of claim 1, wherein the configuration indicates to the RIS to perform spatial modulation of a reflection of the second signaling to indicate acknowledgment or negative acknowledgement (ACK/NACK) encoded bits corresponding to the feedback information.

16. The apparatus of claim 15, wherein the configuration indicates to the RIS to apply an ON/OFF reflection pattern across a plurality of segments of the RIS during the reflection of the second signaling as an indication of the ACK/NACK encoded bits.

17. The apparatus of claim 15, wherein the configuration indicates to the RIS to reduce reflection of the second signaling at a first segment of the RIS as an indication of an ACK/NACK encoded bit value of zero and to optimize reflection of the second signaling at a second segment of the RIS as an indication of an ACK/NACK encoded bit value of one.

18. A processor for wireless communication, comprising: at least one controller coupled with at least one memory and configured to cause the processor to: transmit, to a reconfigurable intelligent surface (RIS), a first signaling indicating a configuration for feedback associated with side control information (SCI) transmitted to the RIS over a control link (C-link); and receive, from the RIS, a second signaling indicating feedback information by modulation of the second signaling according to the configuration indicated by the first signaling.

19. An apparatus for wireless communication, comprising: at least one memory; and at least one processor coupled with the at least one memory and configured to cause the apparatus to: receive a first signaling indicating a configuration for feedback associated with side control information (SCI) transmitted to the apparatus over a control link (C-link); receive a second signaling; and transmit, as a reflected signaling, the second signaling indicating feedback information by modulating the second signaling according to the configuration indicated by the first signaling.

20. A method, comprising: transmitting, to a reconfigurable intelligent surface (RIS), a first signaling indicating a configuration for feedback associated with side control information (SCI) transmitted to the RIS over a control link (C-link); and receiving, from the RIS, a second signaling indicating feedback information by modulation of the second signaling according to the configuration indicated by the first signaling.