Spatial filter mapping and random access process for reconfigurable smart surfaces

Abstract

Example embodiments include methods, apparatus, and computer-readable media for wireless communications to be performed by a user equipment (UE), including receiving a synchronization signal block (SSB) from a base station via a reconfigurable smart surface (RIS), the SSB corresponding to a first SSB type configured for a RIS-assisted procedure. Embodiments also include performing a random access channel (RACH) procedure with the base station based on the SSB. Additionally, embodiments also include sending an indication to the base station that the SSB corresponds to the first SSB type as part of the RACH procedure based on the SSB.

Description

Technical Field

[0001] The present disclosure relates generally to communication systems and, more particularly, to spatial filter mapping and random access channel (RACH) procedures using reconfigurable smart surfaces. Background Art

[0002] Wireless communication systems are widely deployed to provide a variety of telecommunication services such as telephony, video, data, messaging, and broadcast. Typical wireless communication systems may employ multiple access technologies that are capable of supporting communications with multiple users by sharing available system resources. Examples of such multiple access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single carrier frequency division multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems.

[0003] These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate at a city, country, regional, or even global level. An example telecommunication standard is 5G New Radio (NR). 5G NR is part of the continued mobile broadband evolution released by the 3rd Generation Partnership Project (3GPP) to meet new requirements associated with latency, reliability, security, scalability (e.g., with the Internet of Things (IoT)), and other needs. 5G NR includes services related to enhanced mobile broadband (eMBB), massive machine type communications (mMTC), and ultra-reliable low latency communications (URLLC). Some aspects of 5G NR may be based on the 4G Long Term Evolution (LTE) standard. Further improvements are required for 5G NR technology. Wireless communications may involve the transmission and propagation of signals using reconfigurable smart surfaces (RIS). This article describes the improvements. These improvements may also be applicable to other multiple access technologies and telecommunication standards that adopt these technologies. Summary of the invention

[0004] A simplified summary of one or more aspects is given below to provide a basic understanding of these aspects. This summary is not an extensive overview of all expected aspects, and its purpose is neither to identify the key or important elements of all aspects, nor to describe the scope of any or all aspects. Its only purpose is to present some concepts of one or more aspects in a simplified form as a prelude to a more detailed description that is presented later.

[0005] Example embodiments include a wireless communication method performed by a user equipment (UE), comprising: receiving a synchronization signal block (SSB or synchronization signal (SS) / physical broadcast channel (PBCH) block) from a base station via a reconfigurable intelligent surface (RIS), the SSB corresponding to a first SSB type configured for a RIS-assisted procedure. The method also includes performing a random access channel (RACH) procedure with the base station based on the SSB. Additionally, the method also includes sending an indication to the base station as part of the RACH procedure that the SSB corresponds to the first SSB type based on the SSB.

[0006] Another example embodiment includes an apparatus for wireless communication performed by a user equipment (UE), comprising a memory and a processor in communication with the memory. The processing is configured to: receive a synchronization signal block (SSB or synchronization signal (SS) / physical broadcast channel (PBCH) block) from a base station via a reconfigurable intelligent surface (RIS), the SSB corresponding to a first SSB type configured for a RIS-assisted process. The processor is also configured to perform a random access channel (RACH) process with the base station based on the SSB. Additionally, the processor is further configured to send an indication to the base station that the SSB corresponds to a first SSB type as part of the RACH process based on the SSB.

[0007] Another example embodiment includes an apparatus for wireless communication performed by a user equipment (UE), including means for receiving a synchronization signal block (SSB or synchronization signal (SS) / physical broadcast channel (PBCH) block) from a base station via a reconfigurable intelligent surface (RIS), the SSB corresponding to a first SSB type configured for a RIS-assisted procedure. The apparatus also includes means for performing a random access channel (RACH) procedure with the base station based on the SSB. Additionally, the apparatus also includes means for sending an indication to the base station that the SSB corresponds to the first SSB type as part of the RACH procedure based on the SSB.

[0008] Another example embodiment includes a computer-readable medium (e.g., a non-transitory computer-readable medium) including instructions stored for wireless communication performed by a user equipment (UE), the instructions executable by a processor to receive a synchronization signal block (SSB or synchronization signal (SS) / physical broadcast channel (PBCH) block) from a base station via a reconfigurable smart surface (RIS), the SSB corresponding to a first SSB type configured for a RIS-assisted procedure. The instructions may also be executable to perform a random access channel (RACH) procedure with the base station based on the SSB. Additionally, the instructions may also be executable to send an indication to the base station that the SSB corresponds to a first SSB type as part of the RACH procedure based on the SSB.

[0009] To accomplish the above and related ends, one or more aspects include the features fully described and particularly pointed out in the appended claims. The following description and drawings set forth in detail certain illustrative features of one or more aspects. However, these features are indicative of only a few of the various ways in which the principles of the various aspects may be employed, and this description is intended to include all such aspects and their equivalents. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is a schematic diagram illustrating an example of a wireless communication system and an access network according to various aspects of the present disclosure.

[0011] Figure 2A is a diagram illustrating an example of a first frame according to various aspects of the present disclosure.

[0012] Figure 2B is a diagram illustrating an example of DL channels within a subframe according to various aspects of the present disclosure.

[0013] Figure 2C is a diagram illustrating an example of a second frame according to various aspects of the present disclosure.

[0014] Figure 2D is a diagram illustrating an example of UL channels within a subframe according to various aspects of the present disclosure.

[0015] Figure 3 is a schematic diagram illustrating examples of hardware components of a base station and a user equipment (UE) in an access network according to various aspects of the present disclosure.

[0016] Figure 4 is a schematic diagram illustrating an example of a wireless communication system according to various aspects of the present disclosure.

[0017] Figure 5 is a diagram illustrating an example synchronization signal block (SSB) according to various aspects of the present disclosure.

[0018] Figure 6 is a diagram illustrating an example of SSB transmission according to various aspects of the present disclosure.

[0019] Figure 7 is a schematic diagram illustrating an example of a wireless communication system according to various aspects of the present disclosure.

[0020] Figure 8 is a schematic diagram illustrating example signal transmission and reception paths between a base station and a UE using a reconfigurable smart surface (RIS) according to various aspects of the present disclosure.

[0021] Fig. 9 is a schematic diagram illustrating an example apparatus according to various aspects of the present disclosure.

[0022] Fig.10 is a flowchart of a wireless communication method performed by a UE according to various aspects of the present disclosure.

[0023] Fig.11 is a flowchart of a first additional or optional step of a wireless communication method performed by a UE according to various aspects of the present disclosure.

[0024] Fig.12 is a flow chart of a second additional or optional step of a wireless communication method performed by a UE according to various aspects of the present disclosure.

[0025] Fig.13 is a flowchart of a third additional or optional step of a wireless communication method performed by a UE according to various aspects of the present disclosure.

[0026] Fig.14 is a flowchart of a fourth additional or optional step of a wireless communication method performed by a UE according to various aspects of the present disclosure.

[0027] Fig.15 is a flowchart of a fifth additional or optional step of a wireless communication method performed by a UE according to various aspects of the present disclosure. DETAILED DESCRIPTION

[0028] The detailed description set forth below in conjunction with the accompanying drawings is intended as a description of various configurations and is not intended to represent the only configuration in which the concepts described herein may be practiced. In order to provide a thorough understanding of the various concepts, the detailed description includes specific details. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. In some instances, well-known structures and components are shown in block diagram form to avoid blurring such concepts.

[0029] A user equipment (UE) in a wireless communication system may perform a conventional channel training process to acquire a channel between a network device and the UE. The conventional channel training process may establish a channel between the network device and the UE, which may not include additional system components or devices (e.g., relay devices, other network devices) in the transmission path. Additionally or alternatively, the UE may perform a reconfigurable intelligent surface (RIS)-assisted channel training process to establish a RIS-assisted channel between the network device and the UE via the RIS. The network device may use the RIS to create a propagation path between the network device and the UE to establish a RIS-assisted channel. The network device may send different types of synchronization signal blocks (SSB or synchronization signal (SS) / physical broadcast channel (PBCH) blocks) according to the type of channel training process to be performed (e.g., conventional or RIS-assisted). The terms SSB and SS / PBCH may be used interchangeably. However, conventional systems do not provide for the UE to indicate to the network device the type of SSB received by the UE. In such a conventional system, the network device may not be able to determine whether to establish a conventional channel or a RIS-assisted channel with the UE.

[0030] The aspects proposed herein provide multiple ways for a UE to indicate to a network device whether to establish a regular channel or a RIS auxiliary channel. Such an indication can allow the network device to determine which channel training process to adopt. In addition, the aspects proposed herein can reduce the complexity and power consumption of the wireless communication system.

[0031] Several aspects of telecommunication systems will now be described with reference to various apparatus and methods. These apparatus and methods will be described in the detailed description that follows and illustrated in the accompanying drawings by various blocks, components, circuits, processes, algorithms, etc. (collectively referred to as "elements"). These elements may be implemented using electronic hardware, computer software, or any combination thereof. Whether these elements are implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system.

[0032] For example, any part of an element or any combination of elements can be implemented as a "processing system" including one or more processors. Examples of processors include microprocessors, microcontrollers, graphics processing units (GPUs), central processing units (CPUs), application processors, digital signal processors (DSPs), reduced instruction set computing (RISC) processors, systems on chip (SoCs), baseband processors, field programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gate logic, discrete hardware circuits, and other suitable hardware configured to perform various functions described throughout the present disclosure. One or more processors in a processing system can execute software. Whether referred to as software, firmware, middleware, microcode, hardware description language, or other, software should be broadly interpreted as meaning instructions, instruction sets, codes, code segments, program codes, programs, subroutines, software components, applications, software applications, software packages, routines, subroutines, objects, executable programs, execution threads, processes, functions, etc.

[0033] Therefore, in one or more example embodiments, the functions described may be implemented in hardware, software, or any combination thereof. If implemented in software, the functions may be stored on a computer-readable medium or encoded as one or more instructions or codes on a computer-readable medium. Computer-readable media include computer storage media. Storage media may be any available medium that a computer can access. As an example and not limitation, such a computer-readable medium may include a random access memory (RAM), a read-only memory (ROM), an electrically erasable programmable ROM (EEPROM), an optical disk storage, a magnetic disk storage, other magnetic storage devices, a combination of computer-readable media of the above types, or any other medium that can be used to store computer executable code in the form of instructions or data structures that can be accessed by a computer.

[0034] Figure 1 is a schematic diagram showing an example of a wireless communication system and access network 100. The wireless communication system (also referred to as a wireless wide area network (WWAN)) includes a base station 102, a UE 104, and an evolved packet core (EPC) 160 and another core network 190 (e.g., a 5G core (5GC)).

[0035] In certain aspects, the UE 104 may include a RIS component 198 configured to receive an SSB via the RIS, perform a RACH procedure based on the SSB, and send an indication of a type of the SSB as part of the RACH procedure.

[0036] The base station 102 may include a macro cell (a high-power cellular base station) and / or a small cell (a low-power cellular base station). A macro cell includes a base station. A small cell includes a femto cell, a pico cell, and a micro cell. A base station 102 configured for 4G LTE (collectively referred to as the Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN)) may be connected to the EPC 160 via a first backhaul link 132 (e.g., an S1 interface). A base station 102 configured for 5G NR (collectively referred to as the Next Generation RAN (NG-RAN)) may be connected to the core network 190 via a second backhaul link 184. The base station 102 may perform, among other functions, one or more of the following functions: transmission of user data, radio channel encryption and decryption, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity), inter-cell interference coordination, connection establishment and release, load balancing, distribution of non-access stratum (NAS) messages, NAS node selection, synchronization, radio access network (RAN) sharing, multimedia broadcast multicast service (MBMS), user and device tracking, RAN information management (RIM), paging, positioning, and delivery of warning messages. The base stations 102 may communicate with each other directly or indirectly (e.g., via EPC 160 or core network 190) via a third backhaul link 134 (e.g., an X2 interface). The first backhaul link 132, the second backhaul link 184, and the third backhaul link 134 may be wired or wireless.

[0037] Base stations 102 can communicate wirelessly with UEs 104. Each base station 102 can provide communication coverage for a corresponding geographic coverage area 110. There may be overlapping geographic coverage areas 110. For example, a small cell 102' can have a coverage area 110' that overlaps with the coverage area 110 of one or more macrocell base stations 102. A network including both small cells and macrocells may be known as a heterogeneous network. A heterogeneous network may also include a home evolved Node B (eNB) (HeNB), which may provide services to a restricted group known as a closed subscriber group (CSG). A communication link 120 between a base station 102 and a UE 104 may include an uplink (UL) (also known as a reverse link) transmission from the UE 104 to the base station 102 and / or a downlink (DL) (also known as a forward link) transmission from the base station 102 to the UE 104. The communication link 120 may use multiple-input multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, and / or transmit diversity. The communication link may be through one or more carriers. Base station 102 / UE 104 may use spectrum with up to Y MHz (e.g., 5 MHz, 10 MHz, 15 MHz, 20 MHz, 100 MHz, 400 MHz, etc.) bandwidth per carrier allocated in a carrier aggregation for up to Yx MHz (x component carriers) in total for transmission in each direction. The carriers may or may not be adjacent to each other. The allocation of carriers may be asymmetric with respect to DL and UL (e.g., more or fewer carriers may be allocated for DL ​​than for UL). A component carrier may include a primary component carrier and one or more secondary component carriers. A primary component carrier may be referred to as a primary cell (PCell) and a secondary component carrier may be referred to as a secondary cell (SCell).

[0038] Some UEs 104 may communicate with each other using a device-to-device (D2D) communication link 158. The D2D communication link 158 may use DL / UL WWAN spectrum. The D2D communication link 158 may use one or more sidelink channels, such as a physical sidelink broadcast channel (PSBCH), a physical sidelink discovery channel (PSDCH), a physical sidelink shared channel (PSSCH), and a physical sidelink control channel (PSCCH). The D2D communication may be through various wireless D2D communication systems, such as, for example, WiMedia, Bluetooth, ZigBee, Wi-Fi based on the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard, LTE, or NR.

[0039] The wireless communication system may also include a Wi-Fi access point (AP) 150 that communicates with a Wi-Fi station (STA) 152 via a communication link 154 in, for example, a 5 GHz unlicensed spectrum. When communicating in an unlicensed spectrum, the STA 152 / AP 150 may perform a clear channel assessment (CCA) prior to communication to determine whether the channel is available.

[0040] Base station 102, whether a small cell 102' or a large cell (e.g., a macro base station), can include an eNB, a gNodeB (gNB), or other types of base stations. Some base stations, such as gNB 180, can operate in one or more frequency bands within the electromagnetic spectrum.

[0041] The electromagnetic spectrum is often subdivided into various categories, bands, channels, etc. based on frequency / wavelength. In 5G NR, the two initial operating frequency bands are identified as the frequency range codes FR1 (410Mhz-7.125GHz) and FR2 (24.25Ghz-52.6GHz). The frequencies between FR1 and FR2 are often referred to as mid-band frequencies. Although a portion of FR1 is greater than 6GHz, FR1 is often (interchangeably) referred to as the "less than 6GHz (sub-6GHz)" band in various documents and articles. FR2 sometimes also encounters a similar naming issue, although it is different from the extremely high frequency (EHF) band (30GHz-300 GHz) identified as the "millimeter wave" band by the International Telecommunication Union (ITU), but it is often (interchangeably) referred to as the "millimeter wave" band in documents and articles.

[0042] With the above in mind, unless otherwise specifically stated, it should be understood that if the term "less than 6 GHz" or similar terms are used herein, it can broadly refer to frequencies that may be less than 6 GHz, frequencies that may be within FR1, or may include mid-band frequencies. In addition, unless otherwise specifically stated, it should be understood that if the term "millimeter wave" or the like is used herein, it can broadly refer to frequencies that may include mid-band frequencies, frequencies that may be within FR2, or frequencies that may be within the EHF band. Communications using mmW radio bands have extremely high path loss and shorter ranges. The mmW base station 180 can utilize beamforming 182 with the UE 104 to compensate for the path loss and short range.

[0043] Base station 180 may transmit beamformed signals in one or more transmit directions 182′ to UE 104. UE 104 may receive beamformed signals from base station 180 in one or more receive directions 182″. UE 104 may also transmit beamformed signals to base station 180 in one or more transmit directions. Base station 180 may receive beamformed signals from UE 104 in one or more receive directions. Base station 180 / UE 104 may perform beam training to determine the best receive and transmit directions for each of base station 180 / UE 104. The transmit and receive directions for base station 180 may or may not be the same. The transmit and receive directions for UE 104 may or may not be the same.

[0044] The EPC 160 may include a mobility management entity (MME) 162, other MMEs 164, a serving gateway 166, a multimedia broadcast multicast service (MBMS) gateway 168, a broadcast multicast service center (BM-SC) 170, and a packet data network (PDN) gateway 172. The MME 162 may communicate with a home subscriber server (HSS) 174. The MME 162 is a control node that handles signaling between the UE 104 and the EPC 160. In general, the MME 162 provides bearer and connection management. All user IP packets are sent through the serving gateway 166, which itself is connected to the PDN gateway 172. The PDN gateway 172 provides UE IP address allocation and other functions. The PDN gateway 172 and the BM-SC 170 are connected to the IP service 176. The IP service 176 may include the Internet, the intranet, the IP multimedia subsystem (IMS), the PS streaming service, and / or other IP services. The BM-SC 170 may provide the functions of MBMS user service provision and delivery. The BM-SC 170 may be used as an entry point for content provider MBMS transmissions, may be used to authorize and initiate MBMS bearer services within a public land mobile network (PLMN), and may be used to schedule MBMS transmissions. The MBMS Gateway 168 may be used to distribute MBMS services to base stations 102 belonging to a multicast broadcast single frequency network (MBSFN) area that broadcasts a specific service, and may be responsible for session management (start / stop) and collecting eMBMS related billing information.

[0045] The core network 190 may include an access and mobility management function (AMF) 192, other AMFs 193, a session management function (SMF) 194, and a user plane function (UPF) 195. The AMF 192 may communicate with a unified data management (UDM) 196. The AMF 192 is a control node that handles signaling between the UE 104 and the core network 190. Generally, the AMF 192 provides QoS flow and session management. All user Internet Protocol (IP) packets are transmitted through the UPF 195. The UPF 195 provides UE IP address allocation and other functions. The UPF 195 is connected to an IP service 197. The IP service 197 may include the Internet, an intranet, an IP multimedia subsystem (IMS), a packet switching (PS) streaming (PSS) service, and / or other IP services.

[0046] A base station may also include and / or be referred to as a gNB, a Node B, an eNB, an access point, a base transceiver station, a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS), an extended service set (ESS), a transmit receive point (TRP), or some other suitable terminology. Base station 102 provides an access point to EPC 160 or core network 190 for UE 104. Examples of UE 104 include a cellular phone, a smart phone, a Session Initiation Protocol (SIP) phone, a laptop, a personal digital assistant (PDA), a satellite radio, a global positioning system, a multimedia device, a video device, a digital audio player (e.g., an MP3 player), a camera, a game console, a tablet, a smart device, a wearable device, a vehicle, an electric meter, a gas pump, a large or small kitchen appliance, a health device, an implant, a sensor / actuator, a display, or any other similarly functional device. Some of UE 104 may be referred to as an Internet of Things device (e.g., a parking meter, a gas pump, a toaster, a vehicle, a heart monitor, etc.). UE 104 may also be referred to as a station, a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communication device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other suitable terminology.

[0047] Although the following description may focus on 5G NR, the concepts described herein may be applicable to other similar areas such as LTE, LTE-A, CDMA, GSM, and other wireless technologies.

[0048] refer to Figure 2A-2D , schematic diagram showing network elements (eg, base station 102, UE 104) that can be used in a wireless communication system and the above Figure 1Examples of different resources for communication between access networks 100 described in . The resources may be time-based, frequency-based, or both time- and frequency-based.

[0049] Figure 2A 200 is a diagram illustrating an example of a first subframe within a 5G NR frame structure. Figure 2B 230 is a diagram illustrating an example of DL channels within a 5G NR subframe. Figure 2C 250 is a diagram illustrating an example of a second subframe within a 5G NR frame structure. Figure 2D 280 is a diagram illustrating an example of UL channels within a 5G NR subframe. The 5G NR frame structure may be frequency division duplex (FDD), where for a particular set of subcarriers (carrier system bandwidth), subframes within a subcarrier set are dedicated to DL or UL, or the 5G / NR frame structure may be time division duplex (TDD), where for a particular set of subcarriers (carrier system bandwidth), subframes within a subcarrier set are dedicated to DL and UL. Figure 2A , 2C In the example provided, the 5G NR frame structure is assumed to be TDD, where subframe 4 is configured with slot format 28 (mostly DL), where D is DL, U is UL, and F is flexible between DL / UL, and subframe 3 is configured with slot format 1 (all UL). Although subframes 3 and 4 are shown in slot formats 1 and 28, respectively, any particular subframe can be configured in any of the various available slot formats 0-61. Slot formats 0 and 1 are both DL and UL, respectively. Other slot formats 2-61 include a mix of DL, UL, and flexible symbols. The UE configures the slot format via a received slot format indicator (SFI) (dynamically via DL control information (DCI) or semi-statically / statically via radio resource control (RRC) signaling). Note that the following description also applies to the 5G NR frame structure as TDD.

[0050] Other wireless communication technologies may have different frame structures and / or different channels. A frame (10 milliseconds) may be divided into 10 equally sized subframes (1 millisecond). Each subframe may include one or more time slots. A subframe may also include mini-slots, which may include 7, 4, or 2 symbols. Each time slot may include 7 or 14 symbols, depending on the time slot configuration. For time slot configuration 0, each time slot may include 14 symbols, and for time slot configuration 1, each time slot may include 7 symbols. The symbols on the DL may be cyclic prefix (CP) OFDM (CP-OFDM) symbols. The symbols on the UL may be CP-OFDM symbols (for high throughput scenarios) or discrete Fourier transform (DFT) spread OFDM (DFT-s-OFDM) symbols (also known as single carrier frequency division multiple access (SC-FDMA) symbols) (for power-limited scenarios; limited to single stream transmission). The number of time slots within a subframe is based on the time slot configuration and parameter set. For slot configuration 0, different parameter sets μ from 0 to 4 consider 1, 2, 4, 8, and 16 slots per subframe, respectively. For slot configuration 1, different parameter sets μ from 0 to 2 consider 2, 4, and 8 slots per subframe, respectively. Therefore, for slot configuration 0 and parameter set μ, there are 14 symbols / slot and 2 μ time slots / subframes. The subcarrier spacing and symbol length / duration are functions of the numerology. The subcarrier spacing can be equal to 2 μ × 15kHz, where μ is parameter set 0 to 4. Therefore, the subcarrier spacing for parameter set μ=0 is 15kHz, and the subcarrier spacing for parameter set μ=4 is 240kHz. The symbol length / duration is inversely related to the subcarrier spacing. Figure 2A-2D An example is provided for a slot configuration 0 with 14 symbols per slot and a parameter set μ=2 with 4 slots per subframe. The slot duration is 0.25 ms, the subcarrier spacing is 60 kHz, and the symbol duration is approximately 16.67 μs. Within a frame set, there may be one or more different bandwidth parts (BWPs) (see Figure 2B ) are frequency division multiplexed. Each BWP can have a specific parameter set.

[0051] A resource grid may be used to represent the frame structure. Each slot includes a resource block (RB) (also referred to as a physical RB (PRB)) extending 12 consecutive subcarriers. The resource grid is divided into a plurality of resource elements (REs). The number of bits carried by each RE depends on the modulation scheme.

[0052] like Figure 2AAs shown, some REs carry reference (pilot) signals (RS) for UEs. RSs may include demodulation RSs (DM-RSs) (indicated as R for one particular configuration, but other DM-RS configurations are possible) and channel state information reference signals (CSI-RSs) for channel estimation at the UE. RSs may also include beam measurement RSs (BRSs), beam refinement RSs (BRRSs), and phase tracking RSs (PT-RSs).

[0053] Figure 2B Examples of various DL channels within a subframe of a frame are shown. The physical downlink control channel (PDCCH) carries DCI in one or more control channel elements (CCEs) (e.g., 1, 2, 4, 8, or 16 CCEs), each CCE including six RE groups (REGs), each REG including 12 consecutive REs in an OFDM symbol of an RB. The PDCCH in one BWP may be referred to as a control resource set (CORESET). The UE is configured to monitor PDCCH candidates in a PDCCH search space (e.g., a common search space, a UE-specific search space) during a PDCCH listening opportunity on the CORESET, wherein the PDCCH candidates have different DCI formats and different aggregation levels. Additional BWPs may be located at a greater and / or lower frequency on the channel bandwidth. The primary synchronization signal (PSS) may be within symbol 2 of a particular subframe of a frame. The UE 104 uses the PSS to determine subframe / symbol timing and physical layer identification. The secondary synchronization signal (SSS) may be within symbol 4 of a particular subframe of a frame. The UE uses the SSS to determine the physical layer cell identification group number and radio frame timing. Based on the physical layer identifier and the physical layer cell identifier group number, the UE can determine the physical cell identifier (PCI). Based on the PCI, the UE can determine the location of the above-mentioned DM-RS. The physical broadcast channel (PBCH) carrying the master information block (MIB) can be logically grouped with the PSS and SSS to form a synchronization signal (SS) / PBCH block (also known as an SS block (SSB)). The MIB provides the system bandwidth and the number of RBs in the system frame number (SFN). The physical downlink shared channel (PDSCH) carries user data, broadcast system information not sent through the PBCH (such as the system information block (SIB)), and paging messages.

[0054] like Figure 2CAs shown, some REs carry DM-RS for channel estimation at the base station (indicated as R for one specific configuration, but other DM-RS configurations are possible). The UE can send DM-RS for the physical uplink control channel (PUCCH) and DM-RS for the physical uplink shared channel (PUSCH). The PUSCH DM-RS can be sent in the first or first two symbols of the PUSCH. The PUCCH DM-RS can be sent in different configurations depending on whether a short PUCCH or a long PUCCH is sent and depending on the specific PUCCH format used. The UE can send a sounding reference signal (SRS). The SRS can be sent in the last symbol of the subframe. The SRS can have a comb structure, and the UE can send the SRS on one of the comb structures. The SRS can be used by the base station for channel quality estimation to enable frequency-dependent scheduling on the UL.

[0055] Figure 2D Examples of various UL channels within a subframe of a frame are shown. The PUCCH may be located as indicated in one configuration. The PUCCH carries uplink control information (UCI), such as scheduling requests, channel quality indicator (CQI), precoding matrix indicator (PMI), rank indicator (RI), and hybrid automatic repeat request (HARQ) ACK / NACK feedback. The PUSCH carries data and may additionally be used to carry a buffer status report (BSR), a power headroom report (PHR), and / or UCI.

[0056] Figure 31 is a block diagram of example hardware components of a base station 102 that communicates with a UE 104 in an access network. In the DL, IP packets from the EPC 160 may be provided to a controller / processor 375. The controller / processor 375 implements layer 3 and layer 2 functions. Layer 3 includes a radio resource control (RRC) layer, and layer 2 includes a service data adaptation protocol (SDAP) layer, a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, and a medium access control (MAC) layer. The controller / processor 375 provides RRC layer functions associated with broadcasting of system information (e.g., MIB, SIB), RRC connection control (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release), inter-radio access technology (RAT) mobility, and measurement configuration for UE measurement reporting; PDCP layer functions associated with header compression / decompression, security (encryption, decryption, integrity protection, integrity verification), and handover support functions; RLC layer functions associated with transmission of upper layer PDUs, error correction through ARQ, concatenation, segmentation, and reassembly of RLC service data units (SDUs), re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functions associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs to transport blocks (TBs), demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority handling, and logical channel priority determination.

[0057] The transmit (TX) processor 316 and the receive (RX) processor 370 implement layer 1 functions associated with various signal processing functions. Layer 1, including the physical (PHY) layer, may include error detection on the transmission channel, forward error correction (FEC) encoding / decoding of the transmission channel, interleaving, rate matching, mapping to the physical channel, modulation / demodulation of the physical channel, and MIMO antenna processing. The TX processor 316 processes the mapping to the signal constellation based on various modulation schemes (e.g., binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), M-phase shift keying (M-PSK), M-quadrature amplitude modulation (M-QAM)). The coded and modulated symbols can then be split into parallel streams. Each stream can then be mapped to an OFDM subcarrier, multiplexed with a reference signal (e.g., a pilot) in the time domain and / or frequency domain, and then combined together using an inverse fast Fourier transform (IFFT) to produce a physical channel carrying a time domain OFDM symbol stream. The OFDM stream is spatially precoded to produce multiple spatial streams. Channel estimates from a channel estimator 374 may be used to determine the coding and modulation schemes and for spatial processing. The channel estimates may be derived from a reference signal and / or channel condition feedback transmitted by the UE 104. Each spatial stream may then be provided to a different antenna 320 via a separate transmitter 318TX. Each transmitter 318TX may modulate an RF carrier with a corresponding spatial stream for transmission.

[0058] At the UE 104, each receiver 354RX receives a signal through its corresponding antenna 352. Each receiver 354RX recovers the information modulated onto the RF carrier and provides the information to a receive (RX) processor 356. The TX processor 368 and the RX processor 356 implement layer 1 functions associated with various signal processing functions. The RX processor 356 can perform spatial processing on the information to recover any spatial stream destined for the UE 104. If multiple spatial streams are destined for the UE 104, they can be combined into a single OFDM symbol stream by the RX processor 356. The RX processor 356 then converts the OFDM symbol stream from the time domain to the frequency domain using a fast Fourier transform (FFT). The frequency domain signal includes a separate OFDM symbol stream for each subcarrier of the OFDM signal. The symbols and reference signals on each subcarrier are recovered and demodulated by determining the most likely signal constellation point sent by the base station 102. These soft decisions can be based on channel estimates calculated by the channel estimator 358. The soft decisions are then decoded and deinterleaved to recover the data and control signals originally sent on the physical channel by the base station 102. The data and control signals are then provided to the controller / processor 359 which implements Layer 3 and Layer 2 functions.

[0059] The controller / processor 359 may be associated with a memory 360 that stores program codes and data. The memory 360 may be referred to as a computer readable medium. In the UL, the controller / processor 359 provides demultiplexing between transport and logical channels, packet reassembly, decryption, header decompression, and control signal processing to recover IP packets from the EPC 160. The controller / processor 359 is also responsible for error detection using an ACK and / or NACK protocol to support HARQ operations.

[0060] Similar to the functions described in conjunction with the DL transmission of the base station 102, the controller / processor 359 provides RRC layer functions associated with system information (e.g., MIB, SIB) acquisition, RRC connection, and measurement reporting; PDCP layer functions associated with header compression / decompression, and security (encryption, decryption, integrity protection, integrity verification); RLC layer functions associated with transmission of upper layer PDUs, error correction through ARQ, concatenation, segmentation and reassembly of RLC SDUs, resegmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functions associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs to TBs, demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority processing, and logical channel priority determination.

[0061] Channel estimates derived by the channel estimator 358 from a reference signal or feedback sent by the base station 102 may be used by the TX processor 368 to select the appropriate coding and modulation schemes and to facilitate spatial processing. The spatial streams generated by the TX processor 368 may be provided to different antennas 352 via separate transmitters 354TX. Each transmitter 354TX may modulate an RF carrier with a corresponding spatial stream for transmission.

[0062] UL transmissions are processed at the base station 102 in a manner similar to that described in conjunction with the receiver functionality at the UE 104. Each receiver 318RX receives a signal through its respective antenna 320. Each receiver 318RX recovers information modulated onto an RF carrier and provides the information to a RX processor 370.

[0063] The controller / processor 375 may be associated with a memory 376 that stores program codes and data. The memory 376 may be referred to as a computer readable medium. In the UL, the controller / processor 375 provides demultiplexing between transport and logical channels, packet reassembly, decryption, header decompression, control signal processing to recover IP packets from the UE 104. The IP packets from the controller / processor 375 may be provided to the EPC 160. The controller / processor 375 is also responsible for error detection using an ACK and / or NACK protocol to support HARQ operations.

[0064] At the UE 104, at least one of the TX processor 368, the RX processor 356, and the controller / processor 359 may be configured to perform operations related to Figure 1 Aspects related to the reconfigurable smart surface component 198.

[0065] Wireless communication systems can be configured to share available system resources and provide various telecommunication services (e.g., telephone, video, data, messaging, broadcast, etc.) based on multiple access technologies such as CDMA systems, TDMA systems, FDMA systems, OFDMA systems, SC-FDMA systems, TD-SCDMA systems, etc. that support communication with multiple users. In many cases, common protocols that facilitate communication with wireless devices are adopted in various telecommunication standards. For example, communication methods associated with enhanced mobile broadband (eMBB), massive machine type communications (mMTC), and ultra-reliable low latency communications (URLLC) may be incorporated into the 5G NR telecommunication standard, while other aspects may be incorporated into the 4G LTE standard. Since mobile broadband technology is part of continuous development, further improvements in mobile broadband remain useful to continue the development of such technology.

[0066] Figure 4 is a schematic diagram illustrating an example of a wireless communication system 400. The wireless communication system 400 may include a base station 102 and a UE 104. Figure 4 The architecture of the system depicted in the above reference is similar in many ways to Figure 1 The architecture of the wireless communication system 100 described above may include additional features not mentioned above. For simplicity, some elements of the wireless communication system 100 described above are omitted.

[0067] The base station 102 may use multiple-input multiple-output (MIMO) antenna technology, including spatial multiplexing, spatial filtering and / or transmit diversity. The base station 102 may include multiple antenna elements configured to perform spatial multiplexing, spatial filtering and / or transmit diversity. For example, the base station 102 may include 64 or more antenna elements in one frequency band and / or 1024 or more antenna elements in another frequency band. Additionally or alternatively, the base station 102 may attempt to increase the gain of the antenna elements by adopting spatial filtering technology and active antenna units (AAUs), thereby increasing throughput. For example, an active antenna unit (not shown) may be used to focus the transmit energy from the base station 102a into a spatially filtered signal 182a directed to the UE 104a. However, the AAU may require a separate radio frequency (RF) chain to be implemented for each antenna port. In such an embodiment, since each of these RF chains needs to actively send and receive signals, the use of the AAU may result in a significant increase in power consumption.

[0068] Additionally, the use of AAU and spatial filtering techniques may not be sufficient to provide services to all UEs 104 in the coverage area of ​​the base station 102. For example, there may be obstructions that prevent the base station 102a from communicating with the UE 104b. The obstruction may be an artificial structure (e.g., a high-rise building, a bridge, etc.) or may be a natural feature of the terrain (e.g., a mountain, an altitude change, etc.). Typically, in a conventional system, an operator may install a second base station 102b (e.g., a macro cell, a micro cell, a femto cell, etc.) to provide service coverage (i.e., a coverage hole) to an area experiencing obstruction. That is, the second base station 102b may communicate with and provide services to the UE 104b. However, this approach may increase the complexity of the wireless communication system 400 and increase costs due to the duplication of active communication equipment. In addition, the power consumption requirements of the wireless communication system 400 may also increase.

[0069] According to certain aspects of the present disclosure, the wireless communication system 400 may further include a RIS 410. The RIS 410 may include a passive surface that may be dynamically configured to manipulate incident electromagnetic waves to change channel conditions. That is, the RIS 410 may be a passive device that may be configured to be affected by the transmission wave without injecting additional power into the transmission wave. The base station 102a may use the RIS 410 to create a propagation path that avoids blocking so as to establish a communication channel between the base station 102a and the UE 104b. The base station 102a may create a propagation path by dynamically controlling one or more of the scattering, reflection, and refraction characteristics of the RIS 410 to redirect the spatially filtered signal 182a between the base station 102a and the UE 104b. That is, the base station 102a may use the RIS 410 to communicate with the UE 104b without the need for a second base station (i.e., 102b). Therefore, the aspects proposed herein may reduce the complexity and / or power consumption of the wireless communication system 400.

[0070] refer to Figure 5 , this schematic shows the Figure 1500 of an example SSB for communication between network elements (e.g., base station 102, UE 104) of the wireless communication system 100 described above. The base station 102 may transmit one or more SSBs using multiple spatially filtered signals in a time division multiplexing (TDM) scheme. Additionally or alternatively, the base station 102 may transmit one or more SSBs using multiple spatially filtered signals in a frequency division multiplexing (FDM) scheme. For example, one or more SSBs may be transmitted according to a synchronization raster. The synchronization raster may indicate time and frequency resources reserved for transmission of the SSBs, which may be used by the UE 104 for synchronization with the base station 102. When performing a cell search, the UE 104 may scan a frequency band according to the synchronization raster. In some aspects, the UE 104 may receive one or more SSBs from the base station 102. Additionally or alternatively, the UE 104 may receive one or more SSBs from multiple base stations 102. The UE 104 may acquire downlink synchronization information and / or system information based on the received one or more SSBs. In some aspects, UE 104 may be located within a certain downlink spatial filter of base station 102 and may therefore receive one SSB from base station 102. That is, UE 104 may be unaware of transmissions of other SSBs within the cell.

[0071] Synchronization signals, such as a primary synchronization signal (PSS) or a secondary synchronization signal (SSS), and a physical broadcast channel (PBCH) may be packaged into a single block and placed together as an SSB 500. The PSS may be used by the UE 104 to determine the subframe / symbol timing of the base station 102 and to determine the physical layer identity. The SSS may be used by the UE 104 to determine the physical layer cell identification group number and the radio frame timing. The PBCH may include a physical broadcast channel demodulation reference signal (PBCH DMR) and a PBCH data signal. In addition, the PBCH may carry a master information block (MIB). The MIB may provide the number of resource blocks (RBs) in the system bandwidth and the system frame number (SFN).

[0072] The SSB 500 may have different patterns or structures depending on parameters such as the subcarrier spacing (SCS) of both the SSB symbols and the data symbols, the frequency range, etc. For example, the SSB 500 may occupy 4 OFDM symbols in the time domain and 240 tones / subcarriers (20 resource blocks) in the frequency domain. In the SSB 500, the PSS may occupy 127 tones / subcarriers (12 resource blocks) of the first OFDM symbol of the SSB. The SSS may occupy 127 tones / subcarriers (12 resource blocks) of the third OFDM symbol of the SSB. The PBCH may completely occupy the second and fourth OFDM symbols (20 resource blocks) and a total of 96 tones / subcarriers (8 resource blocks) above and below the SSS.

[0073] refer to Figure 6 , schematic diagram 600 shows example resources for transmission of SSB 500. Base station 102 may periodically transmit SSB 500 to allow UE 104 to have an opportunity to synchronize with wireless communication system 100 or wireless communication system 400. In some aspects, base station 102 may transmit multiple instances of SSB 500 in a synchronization burst. In a synchronization burst, multiple SSB transmissions may be transmitted within a single time window (e.g., 5 milliseconds). Multiple SSB transmissions may allow coverage enhancement and / or directional beams to UEs in different locations. For example, each SSB in a plurality of SSB transmissions may be transmitted in a corresponding predefined direction. The predefined direction may be configured to result in providing service coverage with each synchronization burst to at least a portion of the spatial coverage area of ​​base station 102. However, base station 102 may be limited by predefined rules in the number of SSBs that may be transmitted within a particular time frame and the corresponding direction of the SSB. These limitations may be based on various factors, including the specific subcarrier spacing used by the system and the frequency band in which the system operates. For example, one band may have a maximum of 4 or 8 SSB transmissions within a synchronization burst, while another band may have a maximum of 64 SSB transmissions.

[0074] like Figure 6 As shown, a frame (e.g., 10 milliseconds) can be divided into two equally sized half radio frames (e.g., 5 milliseconds). Figure 2A As described, each half radio frame may include more time slots. The base station 102 may send a synchronization burst during one of the two half radio frames of each frame according to the synchronization raster. For example, the base station 102 may send a first SSB starting from OFDM symbol 2 of time slot 0 of the half radio frame, a second SSB starting from OFDM symbol 8 of time slot 0 of the half radio frame, a third SSB starting from OFDM symbol 2 of time slot 1 of the half radio frame, and a fourth SSB starting from OFDM symbol 8 of time slot 1 of the half radio frame.

[0075] Additionally or alternatively, base station 102 may transmit each SSB using a corresponding spatial filter, thereby resulting in a spatial region being covered with each synchronization burst. For example, base station 102 may transmit a first SSB using spatial filter 0 to direct the resulting signal in a first direction, use spatial filter 1 to direct the resulting signal in a second direction, use spatial filter 2 to direct the resulting signal in a third direction, and use spatial filter 3 to direct the resulting signal in a fourth direction.

[0076] Understandably, Figure 6The exemplary SSB transmission configuration shown in is only one example of an SSB transmission configuration that can be used without departing from the scope described herein. For example, other configurations may include a different number of spatial filters or a different number of SSB transmissions.

[0077] Figure 7 is a schematic diagram illustrating an example of a wireless communication system 700. The wireless communication system 700 may include a base station 102 and a UE 104. Figure 7 The architecture of the system depicted in the above reference is similar in many ways to Figure 1 and Figure 4 The architecture of the wireless communication system 100 and the wireless communication system 400 described above may include additional features not mentioned above. For simplicity, some elements of the wireless communication system 100 and the wireless communication system 400 described above are omitted.

[0078] In some aspects, the base station 102 may periodically send synchronization bursts including a type 0SSB ("legacy" SSB) for a conventional (or "legacy") channel training process. That is, the legacy channel training process may not include, for example, a RIS 410 for establishing a communication channel between the base station 102 and the UE 104a. In some aspects, the base station 102 may send each type 0SSB of the synchronization burst using a corresponding spatial filter. Each spatial filter may be configured to send a corresponding type 0SSB in a different direction of the spatial coverage area of ​​the base station 102. In such a configuration, the result of the synchronization burst of type 0SSB may be to provide service coverage to at least a portion of the spatial coverage area of ​​the base station 102.

[0079] In some aspects, the base station 102 may periodically transmit synchronization bursts including a type 1 SSB for a RIS assisted channel training procedure. The RIS assisted procedure may include a channel training procedure to establish a communication channel between the base station 102 and the UE 104b using the RIS 410, thereby creating a propagation path between the two terminal devices (i.e., the base station 102 and the UE 104b). Type 1 SSB may include PSS, SSS, and PBCH, which may be distinguished from legacy SSB (type 0 SSB) by being on a separate synchronization frequency or by an indication in the SSS or by an indication in the PBCH.

[0080] In some aspects, the base station 102 may transmit each type 1 SSB of the synchronization burst using a corresponding spatial filter. Each spatial filter may be configured to transmit a corresponding type 1 SSB in a different direction of the spatial coverage area of ​​the base station 102. In such a configuration, the result of the synchronization burst of type 1 SSBs may be to provide service coverage to at least a portion of the spatial coverage area of ​​the base station 102.

[0081] Additionally or alternatively, the base station 102 may use a specific spatial filter to transmit the type 1 SSB of the synchronization burst. The specific spatial filter may be specific to the RIS 410. Furthermore, the base station 102 may control the propagation characteristics of the RIS 410 to ensure that the type 1 SSB is reflected from the RIS 410 in different directions of the spatial coverage area of ​​the RIS 410. For example, the base station 102 may transmit a first type 1 SSB to the RIS 410 in a specific direction and ensure that the first type 1 SSB is reflected from the RIS 410 in a first direction. The base station 102 may also transmit a second type 1 SSB toward the RIS 410 in a specific direction and ensure that the second type 1 SSB is reflected from the RIS 410 in a second direction. The base station 102 may also transmit a third type 1 SSB toward the RIS 410 in a specific direction and ensure that the third type 1 SSB is reflected from the RIS 410 in a third direction. The base station 102 may also transmit a fourth type 1 SSB toward the RIS 410 in a specific direction and ensure that the fourth type 1 SSB is reflected from the RIS 410 in a fourth direction. In some aspects, the reflection direction can be configured to provide service coverage to at least a portion of the spatial coverage area of ​​base station 102 that is reachable by RIS 410. In some implementations, base station 102 can use the described techniques to provide service coverage to an area experiencing congestion without requiring a second base station 102.

[0082] In certain aspects, one or more of the Type 1 SSBs broadcast from the RIS 410 may be received by the UE 104b. For example, the UE 104b may be located in a coverage hole of a base station 102 covered by the RIS 410.

[0083] Aspects presented herein provide for allowing UEs that are unaware of reconfigurable smart surfaces (e.g., "legacy" UEs) to remain deployed in an enterprise, extending their useful life, while allowing newer RIS-aware UEs to be introduced when deemed appropriate. Although legacy UEs may not be aware of the presence of RIS, in some aspects, legacy UEs may use RIS as a reflector to receive transmission signals from a base station. That is, RIS may appear as a random object or reflector in a transmission environment and may reflect signals from a base station to a legacy UE. However, both the legacy UE and the base station may not be aware of the presence of RIS. In this case, a legacy UE may receive a broadcast or unicast signal sent by a base station. For example, a legacy UE may receive type 0SSB from base station 102. In addition, type 1SSB may be configured such that a legacy UE cannot receive type 1SSB transmissions. Therefore, a legacy UE may perform a conventional channel training procedure, but may not perform a RIS-assisted channel training procedure.

[0084] Further references Figure 7, UE 104a may receive type 0SSB from base station 102. UE 104a may receive type 0SSB without RIS 410 present. Based on receiving type 0SSB, UE 104a may determine that RIS assisted process may not be needed and may continue to perform conventional channel training process. In some aspects, UE 104a may also receive type 1SSB (not shown). However, UE 104a may prioritize received type 0SSB over received type 1SSB. That is, if or when UE 104a receives type 0SSB and type 1SSB, UE 104a may select type 0SSB instead of type 1SSB and perform conventional channel training process according to type 0SSB.

[0085] Additionally or alternatively, the UE 104a may receive a Type 0SSB after having been reflected by a RIS (not shown). For example, the UE 104a may receive a Type 0SSB that may not have been reflected by the RIS 410. Based on receiving the Type 0SSB, the UE 104a may continue to perform a conventional channel training procedure according to the Type 0SSB.

[0086] After the type 1 SSB transmission has been reflected by the RIS 410, the UE 104b may receive a type 1 SSB from the base station 102. Based on receiving the type 1 SSB, the UE 104b may determine that a RIS assisted process may be required and may continue to perform the RIS assisted channel training process. In some aspects, the UE 104b may also receive a type 0 SSB (not shown). However, the UE 104b may prioritize the received type 0 SSB over the received type 1 SSB. That is, if or when the UE 104b receives a type 0 SSB and a type 1 SSB, the UE 104b may select the type 0 SSB instead of the type 1 SSB and perform a conventional channel training process based on the type 0 SSB.

[0087] Some aspects presented herein enable UE 104b to indicate to base station 102 that a RIS assisted channel training procedure may be required based on a determination that a Type 1 SSB was received. Thus, aspects presented herein may allow base station 102 to determine that UE 104b received a Type 1 SSB and may require a RIS assisted channel training procedure.

[0088] Figure 88 is a diagram 800 illustrating example signal transmission and reception paths between a base station 102 and a UE 104 using a RIS 410. The signal transmission and reception paths 800 are associated with the base station 102 using the RIS 410 to initiate the transmission of a Type 1 SSB for a RIS-assisted channel training procedure with the UE 104. In some aspects, spatial filter correspondence may be maintained between the base station 102 and the RIS 410 and between the RIS 410 and the UE 104.

[0089] At 810, base station 102 may transmit a synchronization burst including N type 1 SSBs using a specific transmit spatial filter (e.g., beam k) of base station 102, where N is an integer greater than 0 (e.g., 1, 2, ..., N). The N SSB transmissions of the synchronization burst may be sent out within a single time window (e.g., 5 milliseconds). The transmit spatial filter k of base station 102 may be directed to RIS 410. Specifically, the transmit spatial filter k of base station 102 may be directed to beam n of RIS 410. The N SSB transmissions may arrive at RIS 410 in a direction corresponding to beam n of RIS 410.

[0090] At 820, base station 102 may dynamically configure RIS 410 to ensure that N SSBs are reflected from RIS 410 in respective directions corresponding to beams 1-N of RIS 410. For example, SSB 1 may be reflected from RIS 410 in a direction corresponding to beam 1 of RIS 410, SSB m may be reflected from RIS 410 in a direction corresponding to beam m of RIS 410, and SSB N may have been reflected from RIS 410 in a direction corresponding to beam N of RIS 410.

[0091] At 830, the UE 104 may receive the SSB m using the receive spatial filter b of the UE 104. The UE 104 may determine that the SSB m corresponds to a type 1 SSB, and may further determine that a RIS-assisted channel training process is required. The UE 104 may determine that the SSB m corresponds to a type 1 SSB based on an indication of the SSB m indicating that the SSB m corresponds to a type 1 SSB. The SSB m may explicitly and / or implicitly indicate that the SSB m corresponds to a type 1 SSB. For example, the SSB m may include data or control information indicating that the SSB m corresponds to a type 1 SSB. Additionally or alternatively, the transmission format of the SSB m may implicitly indicate that the SSB m corresponds to a type 1 SSB. In addition to the content of the SSB, the transmission format of the SSB may include one or more configuration parameters associated with the transmission of the SSB. For example, the transmission format of the SSB may include one or more of a modulation scheme, a coding scheme, a time resource, or a frequency resource for transmitting the SSB. In some aspects, the UE 104 may determine whether the SSB m includes data information or control information indicating that the SSB m corresponds to a type 1 SSB. Additionally or alternatively, the UE 104 may also determine one or more of a modulation scheme, a coding scheme, a time resource, or a frequency resource used to transmit the SSB m to determine whether the SSB m corresponds to a Type 1 SSB.

[0092] UE 104 may further determine that a RIS-assisted channel training procedure is required based at least in part on a determination that SSB m corresponds to a Type 1 SSB.

[0093] Based at least on a determination that SSB m corresponds to a Type 1 SSB and a RIS-assisted channel training procedure is required, at 840, UE 104 may transmit a physical random access channel (PRACH) on a spatial filter corresponding to the spatial filter on which the SSB was received. For example, UE 104 may transmit the PRACH using spatial filter b of UE 104. It should be appreciated that transmitting the PRACH includes transmitting data and / or control information using resources defined by the PRACH, and receiving the PRACH includes receiving data and / or control information using resources defined by the PRACH.

[0094] At 850, the PRACH from UE 104 may arrive at RIS 410 in a direction corresponding to beam m of RIS 410. That is, the PRACH may arrive at RIS 410 in the same direction as SSB m reflected from RIS 410. RIS 410 may be configured to ensure that the PRACH arriving at beam m of RIS 410 is reflected from RIS 410 in a direction corresponding to beam n of RIS 410.

[0095] At 860, the base station 102 may receive the PRACH from the RIS 410 using a receive spatial filter k of the base station 102. The base station 102 may determine that the PRACH is received on a spatial filter k corresponding to the spatial filter k used to transmit the type 1 SSB. Based at least on the determination of the spatial filter correspondence, the base station 102 may further determine that a RIS assisted channel training procedure needs to be performed with the UE 104. That is, the spatial filter correspondence between the spatial filter used to transmit the type 1 SSB and the spatial filter used to receive the PRACH may be used as an indication that the corresponding UE has received the type 1 SSB, and may further indicate that a RIS assisted channel training procedure needs to be performed with the corresponding UE. In some aspects, the PRACH may further indicate a suitable spatial filter for reflecting the type 1 SSB at the RIS 410.

[0096] Additionally or alternatively, the UE 104 may select a random access channel (RACH) opportunity (RO) indicating that the SSB m corresponds to a type 1 SSB and that a RIS assisted channel training procedure is required. The UE 104 may send a PRACH to the base station 102 via the RIS 410 using resources corresponding to the selected RO. In some aspects, the base station 102 may determine that the UE 104 received a type 1 SSB and that a RIS assisted channel training procedure is required with the UE 104 based at least in part on the RO on which the base station 102 received the PRACH.

[0097] In some aspects, the UE 104 may obtain a mapping between the RO and the SSB type. For example, the UE 104 may receive a mapping from the base station 102. The mapping may indicate one or more ROs corresponding to a type 1 SSB. The UE 104 may utilize the mapping between the RO and the SSB type to select an RO indicating that the UE 104 receives a type 1 SSB. Additionally or alternatively, the mapping between the RO and the SSB type may also include a spatial filtering configuration suitable for transmission or reflection at the RIS 410. Thus, the UE 104 may indicate to the base station 102 the type of SSB received by the UE 104 based on the RO selected for sending the PRACH to the base station 102.

[0098] In additional or optional aspects, the UE 104 may obtain a first mapping between the RO and the type 1 SSB. For example, the mapping may indicate one or more ROs corresponding to the type 1 SSB. Additionally or alternatively, the UE 104 may obtain a second mapping between the RO and the type 0 SSB. If or when the UE 104 has determined that the SSB corresponds to the type 1 SSB, the UE 104 may utilize the first mapping to select the RO for sending the PRACH to the base station 102 via the RIS 410. If or when the UE 104 has determined that the SSB corresponds to the type 0 SSB, the UE 104 may utilize the second mapping to select the RO for sending the PRACH to the base station 102 via the RIS 410. Therefore, the UE 104 may indicate to the base station 102 the type of SSB received by the UE 104 based on the selected RO for sending the PRACH to the base station 102.

[0099] In an additional or alternative aspect, the UE 104 may obtain a mapping between ROs and SSBs. For example, the mapping may indicate one or more ROs corresponding to type 0 SSBs or type 1 SSBs. The UE 104 may utilize the mapping to select an RO for sending a PRACH to the base station 102 via the RIS 410 based on the SSB type of the received SSB. Thus, the UE 104 may indicate to the base station 102 the type of SSB received by the UE 104 based on the selected RO for sending the PRACH to the base station 102.

[0100] In other additional or optional aspects, the UE 104 may obtain a set of PRACH preambles corresponding to type 0 SSB and type 1 SSB. For example, a portion of the set of PRACH preambles may correspond to type 0 SSB, and the remainder of the set of PRACH preambles may correspond to type 1 SSB. The UE 104 may select a PRACH preamble based on an SSB indicating the type of SSB received by the UE 104. The PRACH sent by the UE 104 to the base station 102 may include the selected PRACH preamble. Therefore, the UE 104 may indicate to the base station 102 the type of SSB received by the UE 104 based on the PRACH preamble included in the PRACH sent to the base station 102.

[0101] In other optional or additional aspects, the UE 104 may send a physical uplink shared channel (PUSCH) to the base station 102 via the RIS 410. The PUSCH may indicate to the base station 102 that the SSB received by the UE 104 corresponds to a type 1 SSB and that a RIS-assisted channel training process is required. For example, a demodulation reference signal of the PUSCH may indicate that the received SSB corresponds to a type 1 SSB. Additionally or alternatively, a scrambling code of the PUSCH may indicate that the received SSB corresponds to a type 1 SSB. In other optional or additional aspects, the payload of the PUSCH may include an indication that the received SSB corresponds to a type 1 SSB. Additionally or alternatively, the UE 104 may select a PUSCH opportunity indicating that the received SSB corresponds to a type 1 SSB. Each PUSCH opportunity may consist of multiple demodulation reference signal (DMRS) ports and a DMRS sequence. The UE 104 may send the PUSCH to the base station 102 via the RIS 410 using resources corresponding to the selected PUSCH opportunity. Thus, aspects presented herein may allow base station 102 to determine that UE 104 received a Type 1 SSB and may require a RIS assisted channel training procedure.

[0102] Fig. 9 900 is a block diagram of an example apparatus 900 for wireless communication. Apparatus 900 may be a UE or a UE may include apparatus 900. In some aspects, apparatus 900 may include a receiving component 902, a communication manager 904, and a sending component 906, which may communicate with each other (e.g., via one or more buses). As shown, apparatus 900 may communicate with another apparatus 908 (such as a base station or another wireless communication device) using receiving component 902 and sending component 906.

[0103] In some aspects, the apparatus 900 may be configured to perform Figure 4-Figure 8 Additionally or alternatively, the apparatus 900 may be configured to perform one or more processes described herein, such as Figure 10-Figure 1 In some aspects, the apparatus 900 may include the method 1000 of Figure 1 and Figure 3 One or more components of a UE are described.

[0104] The receiving component 902 may receive communications such as reference signals, control information, data communications, or combinations thereof from the apparatus 908. The receiving component 902 may provide the received communications to one or more other components of the apparatus 900, such as the communications manager 904. In some aspects, the receiving component 902 may perform signal processing (such as filtering, amplification, demodulation, analog-to-digital conversion, demultiplexing, deinterleaving, demapping, equalization, interference cancellation, or decoding, etc.) on the received communications and may provide the processed signals to one or more other components. In some aspects, the receiving component 902 may include the above in combination with Figure 1 and Figure 3 One or more antennas, demodulators, MIMO detectors, receive processors, controllers / processors, memories, or combinations thereof of a described UE.

[0105] The transmission component 906 may transmit communications such as reference signals, control information, data communications, or combinations thereof to the device 908. In some aspects, the communication manager 904 may generate communications and may transmit the generated communications to the transmission component 906 for transmission to the device 908. In some aspects, the transmission component 906 may perform signal processing (such as filtering, amplification, modulation, digital-to-analog conversion, multiplexing, interleaving, mapping, or encoding, etc.) on the generated communications and may transmit the processed signals to the device 908. In some aspects, the transmission component 906 may include the above in combination with Figure 1 and Figure 3 One or more antennas, modulators, transmit MIMO processors, transmit processors, controllers / processors, memories, or combinations thereof of the described UE. In some aspects, the transmit component 906 can be co-located with the receive component 902 in a transceiver or transceiver component.

[0106] The communication manager 904 can receive the SSB and the incoming RACH process signaling and messaging from the receiving component 902, and can provide an indication that the SSB corresponds to a type 1 SSB and an outgoing RACH process signaling and messaging component 906. For example, the communication manager 904 can receive an SSB corresponding to a first SSB type configured for a RIS-assisted process from a base station via the RIS; perform a RACH process with the base station based on the SSB; and send an indication to the base station as part of the RACH process that the SSB corresponds to the first SSB type based on the SSB. In some aspects, the communication manager 904 can include the above in combination with Figure 1 and Figure 3 A controller / processor, a memory, or a combination thereof of a described UE.

[0107] In some aspects, the communication manager 904 may include a component set such as a receiving component 910, an executing component 912, a transmitting component 914, an obtaining component 916, a selecting component 918, or a combination thereof. Alternatively, the component set may be separate and distinct from the communication manager 904. In some aspects, one or more components of the component set may include the above combined Figure 1 The controller / processor, memory, or combination thereof of the described UE may be implemented therein. Additionally or alternatively, one or more components of the component set may be at least partially implemented as software stored in the memory. For example, a component (or a portion of a component) may be implemented as an instruction or code stored in a non-transitory computer-readable medium and executable by a controller or processor to perform the function or operation of the component.

[0108] The receiving component 910 can receive the SSB from the base station via the RIS. For example, the receiving component 910 can receive the SSB reflected by the RIS on the receiving spatial filter of the device 900. The SSB corresponds to a first SSB type configured for the RIS-assisted process and has been transmitted by the base station at multiple SSB resources using the same transmitting spatial filter of the base station.

[0109] The execution component 912 may perform a RIS-assisted channel training process with the base station and based on the SSB. For example, the RIS-assisted channel training process may include a RACH process. In some aspects, as part of the RACH process, the execution component 912 may send a PRACH to the base station on the transmit spatial filter of the device 900. Additionally or alternatively, the execution component 912 may use the selected RO to send the PRACH. Additionally or alternatively, the PRACH sent by the execution component 912 may include the selected PRACH preamble. In some aspects, sending the PRACH on the transmit spatial filter may ensure that the base station receives the PRACH on the receive spatial filter of the base station, and may further ensure that the base station indicates a suitable spatial filter for reflecting the SSB at the RIS.

[0110] As part of the RIS assisted channel training process, transmission component 914 can transmit to the base station an indication that the SSB corresponds to the first SSB type. For example, transmission component 914 can transmit to the base station a PUSCH carrying an indication that the SSB corresponds to the first SSB type.

[0111] The acquisition component 916 can obtain a mapping of SSB types. For example, the acquisition component 916 can obtain a mapping between RACH opportunities and SSB types. Additionally or alternatively, the acquisition component 916 can obtain a PRACH preamble code set corresponding to a first SSB type. In some aspects, the acquisition component 916 can obtain a first mapping between a RACH opportunity and an SSB type corresponding to a first SSB type, and can further obtain a second mapping of SSBs between a RACH opportunity and an SSB type corresponding to a second SSB type. Additionally or alternatively, the mapping can further indicate a spatial filtering configuration suitable for transmission or reflection at the RIS. In some aspects, the acquisition component 916 can obtain the mapping from a base station or from another network device.

[0112] The selection component 918 may select a transport format parameter indicating that the SSB corresponds to a first SSB type. For example, the selection component 918 may select the RO based on the SSB and a mapping between the RACH opportunity and the SSB type. The selected RACH opportunity may indicate that the SSB corresponds to the first SSB type. Additionally or alternatively, the selection component 918 may select a PRACH preamble based on the SSB and a set of PRACH preambles corresponding to the first SSB type. The selected RACH preamble may indicate that the SSB corresponds to the first SSB type. In some aspects, the selection component 918 may select a PUSCH opportunity indicating that the SSB corresponds to the first SSB type.

[0113] refer to Figure 10-Figure 1 8. In operation, the UE 104 may perform a method 1000 of wireless communication. The method 1000 may be performed by the UE 104 (which may include the memory 360 and may be the entire UE 104 or a component of the UE 104 (such as the RIS component 198, the TX processor 368, the RX processor 356, or the controller / processor 359)). The method 1000 may be performed by the UE RIS component 198 in communication with the base station 102.

[0114] exist Fig.10 In block 1002 of , method 1000 may include receiving an SSB from a base station via the RIS, the SSB corresponding to a first SSB type configured for a RIS-assisted procedure. For example, in one aspect, UE 104, RIS component 198, and / or receiving component 910 may be configured to or may include means for receiving an SSB from base station 102 via the RIS 410, the SSB corresponding to a first SSB type configured for a RIS-assisted procedure.

[0115] For example, the receiving in block 1002 may include receiving the SSB using a particular receive spatial filter of the UE 104. In some aspects, the receiving in block 1002 may also include determining, by the UE 104, that the SSB corresponds to a Type 1 SSB and further determining that a RIS assisted channel training procedure is required.

[0116] In addition, for example, the receiving in block 1002 can be performed in response to detecting a type 1 SSB while scanning a frequency band according to a synchronization raster while performing a cell search. The synchronization raster can indicate time and frequency resources reserved for transmission of SSBs, which can be used by UE 104 for synchronization with base station 102.

[0117] At block 1004, method 1000 can include performing a RACH procedure with the base station in accordance with the SSB. For example, in one aspect, UE 104, RIS component 198, and / or performing component 912 can be configured to or can include means for performing a RACH procedure with base station 102 in accordance with the SSB.

[0118] For example, the execution in block 1004 may include performing a RIS assisted channel training procedure in response to a determination that the SSB corresponds to a Type 1 SSB and a further determination that a RIS assisted channel training procedure is required.

[0119] In addition, for example, the execution in block 1004 may be performed to establish a communication channel between the base station 102 and the UE 104 via the RIS 410. The location of the UE 104 may place the UE in a coverage hole within the coverage area of ​​the base station 102. For example, there may be an obstruction that prevents the base station 102 from communicating with the UE 104. The obstruction may be an artificial structure (e.g., a high-rise building, a bridge, etc.) or may be a natural feature of the terrain (e.g., a mountain, an altitude change, etc.). Typically, in a conventional system, an operator may install a second base station 102 (e.g., a macro cell, a micro cell, a femto cell, etc.) to provide service coverage (i.e., a coverage hole) to an area experiencing obstruction. However, the communication channel established via the RIS 410 may allow the UE 104 to access services provided by the base station 102 that are usually inaccessible due to the location of the UE 104. That is, the base station 102 may communicate with the UE 104 using the RIS 410 without the need for a second base station. Therefore, the aspects presented herein may reduce the complexity and power consumption of the wireless communication system.

[0120] At block 1006, method 1000 may include transmitting, as part of a RACH procedure, to a base station an indication that the SSB corresponds to a first SSB type based on the SSB. For example, in one aspect, UE 104, RIS component 198, and / or transmission component 914 may be configured to or may include means for transmitting, as part of a RACH procedure, to base station 102 an indication that the SSB corresponds to a first SSB type based on the SSB.

[0121] For example, the sending in block 1006 may include sending information to the base station 102 via the RIS 410 during the RACH procedure indicating that the UE 104 received an SSB corresponding to a Type 1 SSB and further indicating that a RIS assisted channel training procedure is required.

[0122] In some optional or additional aspects, the sending in block 1006 may include sending a PUSCH to the base station 102 via the RIS 410 indicating that the UE 104 received a type 1 SSB and that a RIS assisted channel training procedure is required. For example, the PUSCH may include a demodulation reference signal indicating that the received SSB corresponds to a type 1 SSB. Additionally or alternatively, a scrambling code of the PUSCH may indicate that the received SSB corresponds to a type 1 SSB. In other optional or additional aspects, a payload of the PUSCH may include an indication that the received SSB corresponds to a type 1 SSB.

[0123] In addition, for example, the sending in block 1006 can be performed to enable the UE 104 to indicate to the base station 102 that a RIS assisted channel training procedure may be required based on the determination that a Type 1 SSB was received. Thus, aspects presented herein can allow the base station 102 to determine that the UE 104 received a Type 1 SSB and that a RIS assisted channel training procedure may be required.

[0124] refer to Fig.11 In an alternative or additional aspect, in block 1102, the receiving in block 1002 may also include receiving an SSB reflected by the RIS on a receive spatial filter of the UE, the SSB having been transmitted at a plurality of SSB resources using the same transmit spatial filter of the base station. For example, in one aspect, the UE 104, the RIS component 198, and / or the receiving component 910 may be configured to or may include means for receiving an SSB reflected by the RIS on a receive spatial filter of the UE, the SSB having been transmitted at a plurality of SSB resources using the same transmit spatial filter of the base station.

[0125] For example, the receiving in block 1102 may include receiving the SSB using a particular receive spatial filter of UE 104. The SSB received in block 1102 may have been transmitted by base station 102 as part of a synchronization burst transmission using the same transmit spatial filter of base station 102, the synchronization burst transmission including N type 1 SSBs, where N is an integer greater than 0 (e.g., 1, 2, ..., N). The N SSB transmissions of the synchronization burst may have been sent out within a single time window (e.g., 5 milliseconds). The transmit spatial filter of base station 102 may have been targeted to RIS 410. Specifically, the transmit spatial filter of base station 102 may be targeted to a particular beam of RIS 410. The N SSB transmissions may arrive at RIS 410 in a direction corresponding to a particular beam of RIS 410. Additionally or alternatively, base station 102 may have dynamically configured RIS 410 to ensure that the N SSBs are reflected from RIS 410 in respective directions corresponding to beams 1-N of RIS 410. For example, SSB 1 may have been reflected from RIS 410 in a direction corresponding to beam 1 of RIS 410 , SSB m may have been reflected from RIS 410 in a direction corresponding to beam m of RIS 410 , and SSB N may have been reflected from RIS 410 in a direction corresponding to beam N of RIS 410 .

[0126] Furthermore, for example, the receiving in block 1102 may be performed to initiate a RIS assisted channel training procedure.

[0127] In this optional or additional aspect, in block 1104, the method 1000 may also include sending the PRACH to the base station 102 on a transmit spatial filter of the UE, wherein the transmit spatial filter of the UE corresponds to a receive spatial filter of the UE that received the SSB. Sending the PRACH on the transmit spatial filter of the UE ensures that the base station 102 receives the PRACH on the receive spatial filter of the base station and indicates the appropriate spatial filter for reflecting the SSB at the RIS 410. For example, in one aspect, the UE 104, the RIS component 198, and / or the transmission component 914 may be configured to or may include means for sending the PRACH to the base station 102 on a transmit spatial filter of the UE 104, wherein the transmit spatial filter of the UE corresponds to a receive spatial filter of the UE that received the SSB. Sending the PRACH on the transmit spatial filter of the UE 104 ensures that the base station 102 receives the PRACH on the receive spatial filter of the base station 102 and indicates the appropriate spatial filter for reflecting the SSB at the RIS 410.

[0128] For example, the transmitting in block 1104 may include transmitting the PRACH on a spatial filter corresponding to the spatial filter on which the SSB was received. The PRACH from the UE 104 may arrive at the RIS 410 in the same direction as the SSB reflected from the RIS 410. The RIS 410 may be configured to ensure that the PRACH arriving from the UE 104 is reflected from the RIS 410 in the same direction as the SSB arriving at the RIS 410. The base station 102 may receive the PRACH from the RIS 410 using the same spatial filter as used to transmit the SSB to the UE 410. It should be understood that transmitting the PRACH includes transmitting data and / or control information using resources defined by the PRACH, and receiving the PRACH includes receiving data and / or control information using resources defined by the PRACH.

[0129] In addition, for example, the transmission in block 1104 may be performed to initiate a RIS assisted channel training procedure and indicate to the base station as part of a RACH procedure that the SSB corresponds to a type 1 SSB. That is, the spatial filter correspondence between the spatial filter used to transmit the type 1 SSB and the spatial filter used to receive the PRACH may be used as an indication that the corresponding UE received the type 1 SSB and may further indicate that a RIS assisted channel training procedure needs to be performed with the corresponding UE. In some aspects, the PRACH may further indicate an appropriate spatial filter for reflecting the type 1 SSB at the RIS 410.

[0130] refer to Fig.12 In another optional or additional aspect, in block 1202, method 1000 may also include obtaining a mapping between RACH occasions (RO) and SSB types. For example, in one aspect, UE 104, RIS component 198, and / or obtaining component 916 may be configured to or may include means for obtaining a mapping between RO and SSB types.

[0131] For example, the obtaining in block 1202 may include obtaining a mapping between ROs and SSB types. For example, the mapping may indicate one or more ROs corresponding to type 1 SSB. Additionally or alternatively, the mapping may further indicate one or more ROs corresponding to type 0 SSB.

[0132] Furthermore, for example, the obtaining in block 1202 may be performed to obtain a RACH opportunity corresponding to a Type 1 SSB, and the UE 104 may use the RACH opportunity to indicate to the base station 102 that the UE 104 received a Type 1 SSB and requires a RIS assisted channel training procedure.

[0133] In this optional or additional aspect, in block 1204, method 1000 may further include selecting a RO based on the SSB and the mapping, the RO indicating that the SSB corresponds to the first SSB type. For example, in one aspect, UE 104, RIS component 198, and / or selection component 918 may be configured to or may include means for selecting a RO based on the SSB and the mapping, the RO indicating that the SSB corresponds to the first SSB type.

[0134] For example, the selection in block 1204 may include selecting a RO corresponding to a Type 1 SSB from a mapping between ROs and SSB types.

[0135] Additionally, for example, the selection in block 1204 may be performed to select a RO that the UE 104 may use to indicate to the base station 102 that the UE 104 received a Type 1 SSB and requires a RIS assisted channel training procedure.

[0136] In this optional or additional aspect, in block 1206, the transmitting in block 1006 may also include transmitting the PRACH using the RO to the base station 102. For example, in one aspect, the UE 104, the RIS component 198, and / or the transmission component 914 may be configured to or may include means for transmitting the PRACH to the base station using the RO.

[0137] For example, the sending in block 1206 may include sending the PRACH to the base station 102 via the RIS 410 using the selected RO. In some aspects, the base station 102 may determine that the UE 104 received a Type 1 SSB and that a RIS-assisted channel training procedure with the UE 104 is required based on the RO on which the base station 102 received the PRACH.

[0138] Additionally, for example, the sending in block 1206 may be performed to indicate to the base station 102 that the UE 104 received a Type 1 SSB and requires a RIS assisted channel training procedure.

[0139] refer to Fig.13 In another optional or additional aspect, in block 1302, method 1000 may further include obtaining a set of PRACH preambles. For example, in one aspect, UE 104, RIS component 198, and / or obtaining component 916 may be configured to or may include means for obtaining a set of PRACH preambles.

[0140] For example, the obtaining in block 1302 may include obtaining a PRACH preamble set corresponding to type 0SSB and type 1SSB. For example, a portion of the PRACH preamble set may correspond to type 0SSB, and the remainder of the PRACH preamble set may correspond to type 1SSB.

[0141] Furthermore, for example, the obtaining in block 1302 may be performed to indicate to the base station 102 the type of SSB received by the UE 104 based on a PRACH preamble included in the PRACH sent to the base station 102 .

[0142] In this optional or additional aspect, in block 1304, method 1000 may further include selecting a PRACH preamble from a set of PRACH preambles, the selected PRACH preamble indicating that the SSB corresponds to a first SSB type. For example, in one aspect, UE 104, RIS component 198, and / or selection component 918 may be configured to or may include means for selecting a PRACH preamble from a set of PRACH preambles, the selected PRACH preamble indicating that the SSB corresponds to a first SSB type.

[0143] For example, the selection in block 1304 may include selecting the PRACH preamble code based on an SSB indicating a type of SSB received by the UE 104.

[0144] In addition, for example, the selection in block 1304 may be performed to indicate to the base station 102 the type of SSB received by the UE 104 based on a PRACH preamble included in the PRACH sent to the base station 102.

[0145] In this optional or additional aspect, in block 1306, execution in block 1004 may further include transmitting the PRACH including the selected PRACH preamble to the base station 102. For example, in one aspect, the UE 104, the RIS component 198, and / or the transmission component 914 may be configured to or may include means for transmitting the PRACH including the selected PRACH preamble to the base station 102.

[0146] For example, the transmitting in block 1306 may include transmitting the PRACH including the selected PRACH preamble to the base station 102 via the RIS 410 .

[0147] In addition, for example, the transmission in box 1306 can be performed to indicate to the base station 102 the type of SSB received by the UE 104 based on the PRACH preamble code included in the PRACH sent to the base station 102.

[0148] Reference Fig.14 In another optional or additional aspect, in block 1402, method 1000 may further include selecting a PUSCH opportunity indicating that the SSB corresponds to the first SSB type. For example, in one aspect, UE 104, RIS component 198, and / or selection component 918 may be configured to or may include means for selecting a PUSCH opportunity indicating that the SSB corresponds to the first SSB type.

[0149] For example, the selecting in block 1402 may include selecting a PUSCH opportunity indicating that the received SSB corresponds to a Type 1 SSB. Each PUSCH opportunity may consist of a plurality of demodulation reference signal (DMRS) ports and a DMRS sequence.

[0150] Moreover, for example, the selection in block 1402 may be performed to determine a PUSCH opportunity that the UE 104 may use to indicate to the base station 102 that the UE 104 has received a Type 1 SSB.

[0151] In this optional or additional aspect, in block 1404, method 1000 may further include sending a PUSCH to a base station at a PUSCH opportunity. For example, in one aspect, UE 104, RIS component 198, and / or transmission component 914 may be configured to or may include means for sending a PUSCH to a base station at a PUSCH opportunity.

[0152] For example, the transmitting in block 1404 may include transmitting the PUSCH to the base station 102 via the RIS 410 using resources corresponding to the selected PUSCH opportunity.

[0153] Additionally, for example, the sending in block 1404 may be performed to indicate to the base station 102 the type of SSB received by the UE 104 based on a PUSCH opportunity used to transmit a PUSCH during a RACH procedure to the base station 102. Thus, aspects presented herein may allow the base station 102 to determine that the UE 104 received a Type 1 SSB and may require a RIS assisted channel training procedure.

[0154] Reference Fig.15 In another optional or additional aspect, in block 1502, method 1000 may also include obtaining a first mapping between a first RO and a first SSB, the first SSB corresponding to a first SSB type. For example, in one aspect, UE 104, RIS component 198, and / or obtaining component 916 may be configured to or may include means for obtaining a first mapping between a first RO and a first SSB, the first SSB corresponding to a first SSB type.

[0155] For example, obtaining in block 1502 may include obtaining a first mapping between a first RO and a first SSB. The first mapping identifies one or more ROs associated with a type 1 SSB.

[0156] Also, for example, the obtaining in block 1502 may be performed to obtain a first RO that UE 104 may use to send PRACH to base station 102. Base station 102 may determine based on the RO used to send PRACH that UE 104 receives a Type 1 SSB and may require a RIS assisted channel training procedure.

[0157] In this optional or additional aspect, in block 1504, method 1000 may also include obtaining a second mapping between a second RO and a second SSB, the second SSB corresponding to a second SSB type, the second SSB type being configured for non-RIS assisted procedures. For example, in one aspect, UE 104, RIS component 198, and / or obtaining component 916 may be configured to or may include means for obtaining a second mapping between a second RO and a second SSB, the second SSB corresponding to a second SSB type, the second SSB type being configured for non-RIS assisted procedures.

[0158] For example, the obtaining in block 1504 may include obtaining a second mapping between a second RO and a second SSB. The second mapping identifies one or more ROs associated with a type 0SSB. Type 0SSB (or "legacy" SSB) may be specified for a conventional (or "legacy") channel training process. That is, a legacy channel training process may not include, for example, a RIS 410 for establishing a communication channel between a base station 102 and a UE 104.

[0159] In some optional or additional aspects, the obtaining component 916 may also be configured to obtain a third mapping between ROs and type 1SSBs and type 0SSBs. For example, a portion of the third mapping may identify one or more ROs associated with type 1SSBs. Another portion of the third mapping may also identify one or more ROs associated with type 0SSBs.

[0160] In other optional or additional aspects, the mapping between RO and SSB may also include a spatial filtering configuration suitable for transmission or reflection via RIS 410.

[0161] Additionally, for example, the obtaining in block 1504 may be performed to obtain a first RO that the UE 104 may use to send the PRACH to the base station 102. The base station 102 may determine, based on the RO used to send the PRACH, that the UE 104 receives a type 0SSB and that a non-RIS-assisted (e.g., “regular”) channel training procedure may be required.

[0162] It should be understood that the specific order or hierarchy of the blocks in the disclosed process / flowchart is an illustration of an example method. Based on design preferences, it is understood that the specific order or hierarchy of the blocks in the process / flowchart can be rearranged. In addition, some blocks can be combined or omitted. The attached method claims present the elements of the various blocks in an example order and are not meant to be limited to the specific order or hierarchy presented.

[0163] In one example scenario, according to various aspects of the present disclosure, the base station 102 can send one or more type 1 SSBs via the RIS 410. The one or more type 1 SSBs can be sent by the base station 102 in a synchronization burst according to a synchronization raster. The type 1 SSBs can be configured for a RIS assisted channel training procedure. The base station 102 can also perform a RACH procedure with the UE 104 according to the SSBs. As part of the RACH procedure, the base station 102 can receive an indication that the UE 104 received the type 1 SSB.

[0164] In some optional or additional aspects, the base station 102 may transmit one or more type 1 SSBs at multiple SSB resources using the same transmit spatial filter of the base station. In these aspects, the UE 104 may receive at least one type 1 SSB reflected by the RIS 410 on the receive spatial filter of the UE 104. In other aspects, performing the RACH procedure may include receiving, by the base station 102, from the UE 410 a PRACH that has been transmitted on the transmit spatial filter of the UE 104. In response to receiving the PRACH on the receive spatial filter of the base station 102, the base station 102 may indicate an appropriate spatial filter for reflecting the type 1 SSB at the RIS 410.

[0165] In other optional or additional aspects, the base station 102 can obtain a mapping between ROs and SSB types. For example, a first portion of the mapping can correspond to a type 1 SSB, and a second portion of the mapping can correspond to a type 0 SSB. Additionally or alternatively, the mapping can include a first mapping between a first RO and a type 1 SSB and a second mapping between a second RO and a type 0 SSB. In some aspects, the mapping can also include a spatial filtering configuration suitable for transmission or reflection at the RIS 410. In other aspects, the base station 102 can provide a mapping to the UE 104.

[0166] In other optional or additional aspects, performing the RACH procedure can include receiving, by the base station 102, a PRACH using a particular RO from the UE 104. The base station 102 can determine that the UE 104 receives a Type 1 SSB based at least in part on the particular RO and a mapping between the RO and the SSB type.

[0167] In some optional or additional aspects, the base station 102 may obtain a set of PRACH preambles. In these aspects, performing the RACH procedure may include receiving, by the base station 102, a PRACH including a particular PRACH preamble from the UE 104. The base station 102 may determine that the UE 104 receives a Type 1 SSB based at least in part on the particular PRACH preamble and the set of PRACH preambles.

[0168] In other optional or additional aspects, performing the RACH process may include receiving, by the base station 102 via the RIS 410, a PUSCH from the UE 104 indicating that the UE 104 has received a type 1 SSB and that a RIS-assisted channel training process is required. The base station 102 may determine whether the UE 104 has received a type 1 SSB based on the indication in the PUSCH. For example, the PUSCH may include a demodulation reference signal indicating that the received SSB corresponds to a type 1 SSB. Additionally or alternatively, the scrambling code of the PUSCH may indicate that the received SSB corresponds to a type 1 SSB. In other optional or additional aspects, the payload of the PUSCH may include an indication that the received SSB corresponds to a type 1 SSB. Additionally or alternatively, a PUSCH opportunity for sending the PUSCH may indicate that the received SSB corresponds to a type 1 SSB. Each PUSCH opportunity may consist of multiple demodulation reference signal (DMRS) ports and a DMRS sequence.

[0169] The foregoing description is provided to enable any person skilled in the art to practice the various aspects described herein. It will be apparent to those skilled in the art that various modifications to these aspects will be apparent, and the general principles defined herein may be applied to other aspects. Therefore, the claims are not intended to be limited to the aspects shown herein, but are given the full scope consistent with the language claims, unless specifically so stated, otherwise a singular reference to an element is not intended to mean "one and only one", but "one or more". Terms such as "if", "when ......" and "while ......" should be interpreted as meaning "under the conditions of ......", rather than implying a direct temporal relationship or reaction. That is, these phrases (such as "when ......") do not imply an immediate action in response to an action or during the occurrence of an action, but only imply that if the conditions are met, the action will occur, but no specific or immediate time constraints are required for the action to occur. The word "exemplary" is used herein to mean "used as an example, instance or illustration". Any aspect described as "exemplary" herein is not necessarily interpreted as being more preferred or more advantageous than other aspects. Unless otherwise specifically stated, the word "some" refers to one or more. Combinations such as “at least one of A, B, or C,” “one or more of A, B, or C,” “at least one of A, B and C,” “one or more of A, B, and C,” and “A, C, C, or any combination thereof” include any combination of A, B, and / or C, and may include multiple A, multiple B, or multiple C. Specifically, combinations such as “at least one of A, B, or C,” “one or more of A, B, or C,” “at least one of A, B, and C,” “one or more of A, B, and C,” and “A, B, C, or any combination thereof” may be only A, only B, only C, A and B, A and C, B and C, or A and B and C, wherein any such combination may include one or more members of A, B, or C. All structural and functional equivalents to the elements of the various aspects described throughout the present disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. In addition, nothing disclosed herein is intended to be exclusive to the disclosure, regardless of whether such disclosure is explicitly recited in the claims. The words “module,” “mechanism,” “element,” “device,” etc. cannot replace the word “part.” Therefore, any claim element cannot be interpreted as a part-plus-function unless the element is explicitly recited using the phrase “means for . . . .”

Claims

1. A wireless communication method performed by a user equipment (UE), comprising: receiving a synchronization signal block (SSB) from a base station via a reconfigurable smart surface (RIS), the SSB corresponding to a first SSB type configured for a RIS-assisted procedure; performing a random access channel (RACH) procedure with the base station according to the SSB; as well as As part of the RACH process, an indication is sent to the base station based on the SSB that the SSB corresponds to the first SSB type.

2. The method according to claim 1, wherein: Receiving the SSB corresponding to the first SSB type configured for the RIS assisted process includes receiving the SSB reflected by the RIS on a receive spatial filter of the UE, the SSB having been transmitted at a plurality of SSB resources using a same transmit spatial filter of the base station; as well as Performing the RACH procedure includes sending a physical random access channel (PRACH) to the base station over a transmit spatial filter of the UE corresponding to the receive spatial filter of the UE that received the SSB.

3. The method according to claim 1, further comprising: Get the mapping between RACH opportunity (RO) and SSB type; selecting a RO based on the SSB and the mapping, the RO indicating that the SSB corresponds to the first SSB type; as well as The performing of the RACH process includes sending a physical random access channel (PRACH) to the base station using the RO.

4. The method according to claim 1, further comprising: Obtain a physical random access channel (PRACH) preamble set; Selecting a PRACH preamble from the set of PRACH preambles, the selected PRACH preamble indicating that the SSB corresponds to the first SSB type; as well as The performing of the RACH process includes sending a PRACH including the selected PRACH preamble code to the base station.

5. The method according to claim 1, further comprising: sending a physical uplink shared channel (PUSCH) to the base station carrying the indication that the SSB corresponds to the first SSB type, wherein: The demodulation reference signal of the PUSCH indicates that the SSB corresponds to the first SSB type; or The scrambling code of the PUSCH indicates that the SSB corresponds to the first SSB type; or The payload of the PUSCH includes the indication that the SSB corresponds to the first SSB type.

6. The method according to claim 1, further comprising: selecting a physical uplink shared channel (PUSCH) opportunity indicating that the SSB corresponds to the first SSB type; as well as Sending a PUSCH to the base station at the PUSCH opportunity.

7. The method according to claim 1, further comprising: Obtaining a first mapping between a first RACH opportunity (RO) and a first SSB, the first SSB corresponding to the first SSB type; as well as A second mapping between a second RO and a second SSB is obtained, the second SSB corresponding to a second SSB type, the second SSB type being configured for a non-RIS assisted process.

8. The method according to claim 1, further comprising: A mapping between RACH occasions (ROs) and SSBs is obtained, a first portion of the SSBs corresponding to the first SSB type, and a second portion of the SSBs corresponding to a second SSB type, the second SSB type being configured for a non-RIS assisted process.

9. The method according to claim 1, further comprising: A mapping between a RACH opportunity (RO) and a first SSB corresponding to the first SSB type is obtained, the mapping indicating a spatial filtering configuration suitable for transmission or reflection at the RIS.

10. An apparatus for wireless communication performed by a user equipment (UE), comprising: Memory; as well as a processor communicatively coupled to the memory and configured to: receiving a synchronization signal block (SSB) from a base station via a reconfigurable smart surface (RIS), the SSB corresponding to a first SSB type configured for a RIS-assisted procedure; performing a random access channel (RACH) procedure with the base station according to the SSB; as well as As part of the RACH process, an indication is sent to the base station based on the SSB that the SSB corresponds to the first SSB type.

11. The device according to claim 10, wherein: Receiving the SSB corresponding to the first SSB type configured for the RIS assisted process includes receiving the SSB reflected by the RIS on a receive spatial filter of the UE, the SSB having been transmitted at a plurality of SSB resources using a same transmit spatial filter of the base station; as well as Performing the RACH procedure includes sending a physical random access channel (PRACH) to the base station over a transmit spatial filter of the UE corresponding to the receive spatial filter of the UE that received the SSB.

12. The device according to claim 10, wherein: The processor is further configured to: Get the mapping between RACH opportunity (RO) and SSB type; selecting a RO based on the SSB and the mapping, the RO indicating that the SSB corresponds to the first SSB type; as well as The performing of the RACH process includes sending a physical random access channel (PRACH) to the base station using the RO.

13. The device according to claim 10, wherein: The processor is further configured to: Obtain a physical random access channel (PRACH) preamble set; Selecting a PRACH preamble from the set of PRACH preambles, the selected PRACH preamble indicating that the SSB corresponds to the first SSB type; as well as The performing of the RACH process includes sending a PRACH including the selected PRACH preamble code to the base station.

14. The device according to claim 10, wherein: The processor is further configured to: sending a physical uplink shared channel (PUSCH) to the base station carrying the indication that the SSB corresponds to the first SSB type, wherein: The demodulation reference signal of the PUSCH indicates that the SSB corresponds to the first SSB type; or The scrambling code of the PUSCH indicates that the SSB corresponds to the first SSB type; or The payload of the PUSCH includes the indication that the SSB corresponds to the first SSB type.

15. The device according to claim 10, wherein: The processor is further configured to: selecting a physical uplink shared channel (PUSCH) opportunity indicating that the SSB corresponds to the first SSB type; and Sending a PUSCH to the base station at the PUSCH opportunity.

16. The device according to claim 10, wherein: The processor is further configured to: Obtaining a first mapping between a first RACH opportunity (RO) and a first SSB, the first SSB corresponding to the first SSB type; as well as A second mapping between a second RO and a second SSB is obtained, the second SSB corresponding to a second SSB type, the second SSB type being configured for a non-RIS assisted process.

17. The device according to claim 10, wherein: The processor is further configured to: A mapping between RACH occasions (ROs) and SSBs is obtained, a first portion of the SSBs corresponding to the first SSB type, and a second portion of the SSBs corresponding to a second SSB type, the second SSB type being configured for a non-RIS assisted process.

18. The device according to claim 10, wherein: The processor is further configured to: A mapping between a RACH opportunity (RO) and a first SSB corresponding to the first SSB type is obtained, the mapping indicating a spatial filtering configuration suitable for transmission or reflection at the RIS.

19. An apparatus for wireless communication performed by a user equipment (UE), comprising: means for receiving a synchronization signal block (SSB) from a base station via a reconfigurable smart surface (RIS), the SSB corresponding to a first SSB type configured for a RIS-assisted procedure; means for performing a random access channel (RACH) procedure with the base station according to the SSB; as well as means for sending, as part of the RACH procedure, to the base station an indication that the SSB corresponds to the first SSB type based on the SSB.

20. The apparatus of claim 19, wherein: The means for receiving the SSB corresponding to the first SSB type configured for the RIS assisted procedure further comprises means for receiving the SSB reflected by the RIS on a receive spatial filter of the UE, the SSB having been transmitted at a plurality of SSB resources using the same transmit spatial filter of the base station; as well as The means for performing the RACH procedure also includes means for transmitting a physical random access channel (PRACH) to the base station on a transmit spatial filter of a UE corresponding to the receive spatial filter of the UE that received the SSB.

21. The apparatus according to claim 19, further comprising: Means for obtaining a mapping between RACH occasions (RO) and SSB types; means for selecting a RO based on the SSB and the mapping, the RO indicating that the SSB corresponds to the first SSB type; as well as The component for performing the RACH process further includes a component for sending a physical random access channel (PRACH) to the base station using the RO.

22. The apparatus of claim 19, further comprising: means for obtaining a set of physical random access channel (PRACH) preambles; means for selecting a PRACH preamble from the set of PRACH preambles, the selected PRACH preamble indicating that the SSB corresponds to the first SSB type; and The component for performing the RACH process further includes a component for sending a PRACH including the selected PRACH preamble code to the base station.

23. The apparatus of claim 19, further comprising: means for sending, to the base station, a physical uplink shared channel (PUSCH) carrying the indication that the SSB corresponds to the first SSB type, wherein: The demodulation reference signal of the PUSCH indicates that the SSB corresponds to the first SSB type; or The scrambling code of the PUSCH indicates that the SSB corresponds to the first SSB type; or The payload of the PUSCH includes the indication that the SSB corresponds to the first SSB type.

24. The apparatus of claim 19, further comprising: means for selecting a physical uplink shared channel (PUSCH) opportunity indicating that the SSB corresponds to the first SSB type; as well as A means for sending a PUSCH to the base station at the PUSCH opportunity.

25. The apparatus of claim 19, further comprising: means for obtaining a first mapping between a first RACH opportunity (RO) and a first SSB, the first SSB corresponding to the first SSB type; as well as Means for obtaining a second mapping between a second RO and a second SSB, the second SSB corresponding to a second SSB type, the second SSB type configured for non-RIS assisted procedures.

26. The apparatus of claim 19, further comprising: Means for obtaining a mapping between RACH opportunities (ROs) and SSBs, a first portion of the SSBs corresponding to the first SSB type, and a second portion of the SSBs corresponding to a second SSB type, the second SSB type being configured for a non-RIS assisted procedure.

27. The apparatus of claim 19, further comprising: Means for obtaining a mapping between a RACH opportunity (RO) and a first SSB corresponding to the first SSB type, the mapping indicating a spatial filtering configuration suitable for transmission or reflection at the RIS.

28. A computer readable medium comprising stored instructions to be executed by a user equipment (UE) for wireless communication, the instructions being executable by a processor to perform the method of any one of claims 1 to 9.

Images