WO2025264352A1 - Time-space beam index for a higher ssb beam number - Google Patents

Abstract

An apparatus may be a wireless device configured to receive, via a first MIB of a first SSB, a first spatial order index value and obtain, based on the first spatial order index value, RMSI associated with cell acquisition. An apparatus may be a network device configured to simultaneously transmit a plurality of SSBs, where each SSB in the plurality of SSBs includes a different spatial order index value in a plurality of spatial order index values, and obtain, based on a first spatial order index value in the plurality of spatial order index values included in a first SSB in the plurality of SSBs, at least one random access channel (RACH) message associated with a cell acquisition.

Description

TIME-SPACE BEAM INDEX FOR A HIGHER SSB BEAM NUMBER

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of Israel Patent Application Serial No. 313814, entitled “TIME-SPACE BEAM INDEX FOR A HIGHER SSB BEAM NUMBER” and filed on June 21, 2024, which is expressly incorporated by reference herein in its entirety.

TECHNICAL FIELD

[0002] The present disclosure relates generally to communication systems, and more particularly, to wireless communication associated with an initial cell acquisition and/or beam management.

INTRODUCTION

[0003] Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasts. Typical wireless communication systems may employ multiple-access technologies capable of supporting communication 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.

[0004] These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate on a municipal, national, regional, and even global level. An example telecommunication standard is 5G New Radio (NR). 5G NR is part of a continuous mobile broadband evolution promulgated by Third Generation Partnership Project (3 GPP) to meet new requirements associated with latency, reliability, security, scalability (e.g., with Internet of Things (IoT)), and other requirements. 5G NR includes services associated with 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. There exists a need for further improvements in 5G NR technology. These improvements may also be applicable to other multi-access technologies and the telecommunication standards that employ these technologies.

BRIEF SUMMARY

[0005] The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects. This summary neither identifies key or critical elements of all aspects nor delineates the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.

[0006] In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be a wireless device configured to receive, via a first master information block (MIB) of a first synchronization signal block (SSB), a first spatial order index value and obtain, based on the first spatial order index value, remaining minimum system information (RMSI) associated with cell acquisition.

[0007] In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be a network device configured to simultaneously transmit a plurality of SSBs, where each SSB in the plurality of SSBs includes a different spatial order index value in a plurality of spatial order index values, and obtain, based on a first spatial order index value in the plurality of spatial order index values included in a first SSB in the plurality of SSBs, at least one random access channel (RACH) message associated with a cell acquisition.

[0008] To the accomplishment of the foregoing and related ends, the one or more aspects may include the features hereinafter fully described and particularly pointed out in the claims. The following description and the drawings set forth in detail certain illustrative features of the one or more aspects. These features are indicative, however, of but a few of the various ways in which the principles of various aspects may be employed. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] FIG. 1 is a diagram illustrating an example of a wireless communications system and an access network.

[0010] FIG. 2A is a diagram illustrating an example of a first frame, in accordance with various aspects of the present disclosure.

[0011] FIG. 2B is a diagram illustrating an example of downlink (DL) channels within a subframe, in accordance with various aspects of the present disclosure.

[0012] FIG. 2C is a diagram illustrating an example of a second frame, in accordance with various aspects of the present disclosure.

[0013] FIG. 2D is a diagram illustrating an example of uplink (UL) channels within a subframe, in accordance with various aspects of the present disclosure.

[0014] FIG. 3 is a diagram illustrating an example of a base station and user equipment (UE) in an access network.

[0015] FIG. 4 is a first diagram illustrating locations within a slot for SSBs associated with a first sub-carrier spacing (SCS) in accordance with some aspects of the disclosure.

[0016] FIG. 5 is a diagram illustrating the use of a time-space beam index in accordance with some aspects of the disclosure.

[0017] FIG. 6 is a call flow diagram illustrating a method of using a time-space (or spatial) index in accordance with some aspects of the disclosure.

[0018] FIG. 7 is a flowchart of a method of wireless communication.

[0019] FIG. 8 is a flowchart of a method of wireless communication.

[0020] FIG. 9 is a flowchart of a method of wireless communication.

[0021] FIG. 10 is a flowchart of a method of wireless communication.

[0022] FIG. 11 is a diagram illustrating an example of a hardware implementation for an example apparatus and/or network entity.

[0023] FIG. 12 is a diagram illustrating an example of a hardware implementation for an example network entity. DETAILED DESCRIPTION

[0024] In some aspects of wireless communication, different frequency ranges (FRs) may be used. For higher frequency bands (e.g., FR4 (71 GHz - 114.25 GHz), and FR5 (114.25 GHz - 300 GHz)), beams may become narrower to allow sufficient cell coverage due to higher propagation losses. With narrower beams, more SSB beams may be used to provide coverage for a same angular area. However, the use of more beams, in some aspects, may be associated with a larger number of broadcasting resources (e.g., SSB transmission occasions, system information blocks (e.g., SIB1), paging occasions, and, to some extent, RACH occasions). The larger number of broadcasting resources may increase an overhead and/or a time associated with transmitting the larger number of SSB transmission occasions.

[0025] Various aspects relate generally to increasing a beam index by using time-space indexing. Some aspects more specifically relate to the use of a larger number of narrower beams in a high frequency band by transmitting multiple spatial beams (e.g., in different directions) in a same time resource and identifying the spatial beams using an enhanced beam index signaled within a MIB. In some aspects, due to the use of narrower beams in a high frequency band, the beam index may increase. Therefore, it may be desirable to reduce latency by applying spatial beams in the same time resource. This spatial approach may be signaled within a MIB in a specific bitfield. In some examples, a UE may be configured to receive, via a first MIB of a first SSB, a first spatial order index value and obtain, based on the first spatial order index value, RMSI associated with cell acquisition. A network device such as a base station, in some aspects, may be configured to simultaneously transmit a plurality of SSBs, where each SSB in the plurality of SSBs includes a different spatial order index value in a plurality of spatial order index values, and obtain, based on a first spatial order index value in the plurality of spatial order index values included in a first SSB in the plurality of SSBs, at least one RACH message associated with a cell acquisition.

[0026] Particular aspects of the subject matter described in this disclosure can be implemented to realize one or more of the following potential advantages. In some examples, by using time-space indexing, the described techniques can be used to include a higher number of SSB beams per burst, facilitating narrower beams for better cell coverage. [0027] The detailed description set forth below in connection with the drawings describes various configurations and does not represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of various concepts. However, these concepts may be practiced without these specific details. In some instances, well known structures and components are shown in block diagram form in order to avoid obscuring such concepts.

[0028] Several aspects of telecommunication systems are presented with reference to various apparatus and methods. These apparatus and methods are described in the following detailed description 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 such elements are implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system.

[0029] By way of example, an element, or any portion of an element, or any combination of elements may be implemented as a “processing system” that includes one or more processors. When multiple processors are implemented, the multiple processors may perform the functions individually or in combination. 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 a chip (SoC), baseband processors, field programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functionality described throughout this disclosure. One or more processors in the processing system may execute software. Software, whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise, shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software components, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, or any combination thereof.

[0030] Accordingly, in one or more example aspects, implementations, and/or use cases, the functions described may be implemented in hardware, software, or any combination thereof. If implemented in software, the functions may be stored on or encoded as one or more instructions or code on a computer-readable medium. Computer-readable media includes computer storage media. Storage media may be any available media that can be accessed by a computer. By way of example, such computer-readable media can include a random-access memory (RAM), a read-only memory (ROM), an electrically erasable programmable ROM (EEPROM), optical disk storage, magnetic disk storage, other magnetic storage devices, combinations of the types of computer-readable media, 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.

[0031] While aspects, implementations, and/or use cases are described in this application by illustration to some examples, additional or different aspects, implementations and/or use cases may come about in many different arrangements and scenarios. Aspects, implementations, and/or use cases described herein may be implemented across many differing platform types, devices, systems, shapes, sizes, and packaging arrangements. For example, aspects, implementations, and/or use cases may come about via integrated chip implementations and other non-module-component based devices (e.g., end-user devices, vehicles, communication devices, computing devices, industrial equipment, retail/purchasing devices, medical devices, artificial intelligence (Al)-enabled devices, etc.). While some examples may or may not be specifically directed to use cases or applications, a wide assortment of applicability of described examples may occur. Aspects, implementations, and/or use cases may range a spectrum from chip-level or modular components to non-modular, non-chip-level implementations and further to aggregate, distributed, or original equipment manufacturer (OEM) devices or systems incorporating one or more techniques herein. In some practical settings, devices incorporating described aspects and features may also include additional components and features for implementation and practice of claimed and described aspect. For example, transmission and reception of wireless signals necessarily includes a number of components for analog and digital purposes (e.g., hardware components including antenna, RF-chains, power amplifiers, modulators, buffer, processor(s), interleaver, adders/summers, etc.). Techniques described herein may be practiced in a wide variety of devices, chip-level components, systems, distributed arrangements, aggregated or disaggregated components, end-user devices, etc. of varying sizes, shapes, and constitution.

[0032] Deployment of communication systems, such as 5G NR systems, may be arranged in multiple manners with various components or constituent parts. In a 5G NR system, or network, a network node, a network entity, a mobility element of a network, a radio access network (RAN) node, a core network node, a network element, or a network equipment, such as a base station (BS), or one or more units (or one or more components) performing base station functionality, may be implemented in an aggregated or disaggregated architecture. For example, a BS (such as a Node B (NB), evolved NB (eNB), NR BS, 5G NB, access point (AP), a transmission reception point (TRP), or a cell, etc.) may be implemented as an aggregated base station (also known as a standalone BS or a monolithic BS) or a disaggregated base station.

[0033] An aggregated base station may be configured to utilize a radio protocol stack that is physically or logically integrated within a single RAN node. A disaggregated base station may be configured to utilize a protocol stack that is physically or logically distributed among two or more units (such as one or more central or centralized units (CUs), one or more distributed units (DUs), or one or more radio units (RUs)). In some aspects, a CU may be implemented within a RAN node, and one or more DUs may be co-located with the CU, or alternatively, may be geographically or virtually distributed throughout one or multiple other RAN nodes. The DUs may be implemented to communicate with one or more RUs. Each of the CU, DU and RU can be implemented as virtual units, i.e., a virtual central unit (VCU), a virtual distributed unit (VDU), or a virtual radio unit (VRU).

[0034] Base station operation or network design may consider aggregation characteristics of base station functionality. For example, disaggregated base stations may be utilized in an integrated access backhaul (IAB) network, an open radio access network (O-RAN (such as the network configuration sponsored by the O-RAN Alliance)), or a virtualized radio access network (vRAN, also known as a cloud radio access network (C-RAN)). Disaggregation may include distributing functionality across two or more units at various physical locations, as well as distributing functionality for at least one unit virtually, which can enable flexibility in network design. The various units of the disaggregated base station, or disaggregated RAN architecture, can be configured for wired or wireless communication with at least one other unit.

[0035] FIG. 1 is a diagram 100 illustrating an example of a wireless communications system and an access network. The illustrated wireless communications system includes a disaggregated base station architecture. The disaggregated base station architecture may include one or more CUs 110 that can communicate directly with a core network 120 via a backhaul link, or indirectly with the core network 120 through one or more disaggregated base station units (such as a Near-Real Time (Near-RT) RAN Intelligent Controller (RIC) 125 via an E2 link, or a Non-Real Time (Non-RT) RIC 115 associated with a Service Management and Orchestration (SMO) Framework 105, or both). A CU 110 may communicate with one or more DUs 130 via respective midhaul links, such as an Fl interface. The DUs 130 may communicate with one or more RUs 140 via respective fronthaul links. The RUs 140 may communicate with respective UEs 104 via one or more radio frequency (RF) access links. In some implementations, the UE 104 may be simultaneously served by multiple RUs 140.

[0036] Each of the units, i.e., the CUs 110, the DUs 130, the RUs 140, as well as the Near-RT RICs 125, the Non-RT RICs 115, and the SMO Framework 105, may include one or more interfaces or be coupled to one or more interfaces configured to receive or to transmit signals, data, or information (collectively, signals) via a wired or wireless transmission medium. Each of the units, or an associated processor or controller providing instructions to the communication interfaces of the units, can be configured to communicate with one or more of the other units via the transmission medium. For example, the units can include a wired interface configured to receive or to transmit signals over a wired transmission medium to one or more of the other units. Additionally, the units can include a wireless interface, which may include a receiver, a transmitter, or a transceiver (such as an RF transceiver), configured to receive or to transmit signals, or both, over a wireless transmission medium to one or more of the other units. [0037] In some aspects, the CU 110 may host one or more higher layer control functions. Such control functions can include radio resource control (RRC), packet data convergence protocol (PDCP), service data adaptation protocol (SDAP), or the like. Each control function can be implemented with an interface configured to communicate signals with other control functions hosted by the CU 110. The CU 110 may be configured to handle user plane functionality (i.e., Central Unit - User Plane (CU-UP)), control plane functionality (i.e., Central Unit - Control Plane (CU-CP)), or a combination thereof. In some implementations, the CU 110 can be logically split into one or more CU-UP units and one or more CU-CP units. The CU-UP unit can communicate bidirectionally with the CU-CP unit via an interface, such as an El interface when implemented in an O-RAN configuration. The CU 110 can be implemented to communicate with the DU 130, as necessary, for network control and signaling.

[0038] The DU 130 may correspond to a logical unit that includes one or more base station functions to control the operation of one or more RUs 140. In some aspects, the DU 130 may host one or more of a radio link control (RLC) layer, a medium access control (MAC) layer, and one or more high physical (PHY) layers (such as modules for forward error correction (FEC) encoding and decoding, scrambling, modulation, demodulation, or the like) depending, at least in part, on a functional split, such as those defined by 3GPP. In some aspects, the DU 130 may further host one or more low PHY layers. Each layer (or module) can be implemented with an interface configured to communicate signals with other layers (and modules) hosted by the DU 130, or with the control functions hosted by the CU 110.

[0039] Lower-layer functionality can be implemented by one or more RUs 140. In some deployments, an RU 140, controlled by a DU 130, may correspond to a logical node that hosts RF processing functions, or low-PHY layer functions (such as performing fast Fourier transform (FFT), inverse FFT (iFFT), digital beamforming, physical random access channel (PRACH) extraction and filtering, or the like), or both, based at least in part on the functional split, such as a lower layer functional split. In such an architecture, the RU(s) 140 can be implemented to handle over the air (OTA) communication with one or more UEs 104. In some implementations, real-time and non-real-time aspects of control and user plane communication with the RU(s) 140 can be controlled by the corresponding DU 130. In some scenarios, this configuration can enable the DU(s) 130 and the CU 110 to be implemented in a cloud- based RAN architecture, such as a vRAN architecture.

[0040] The SMO Framework 105 may be configured to support RAN deployment and provisioning of non- virtualized and virtualized network elements. For non- virtualized network elements, the SMO Framework 105 may be configured to support the deployment of dedicated physical resources for RAN coverage requirements that may be managed via an operations and maintenance interface (such as an 01 interface). For virtualized network elements, the SMO Framework 105 may be configured to interact with a cloud computing platform (such as an open cloud (O-Cloud) 190) to perform network element life cycle management (such as to instantiate virtualized network elements) via a cloud computing platform interface (such as an 02 interface). Such virtualized network elements can include, but are not limited to, CUs 110, DUs 130, RUs 140 and Near-RT RICs 125. In some implementations, the SMO Framework 105 can communicate with a hardware aspect of a 4G RAN, such as an open eNB (O-eNB) 111, via an 01 interface. Additionally, in some implementations, the SMO Framework 105 can communicate directly with one or more RUs 140 via an 01 interface. The SMO Framework 105 also may include a Non-RT RIC 115 configured to support functionality of the SMO Framework 105.

[0041] The Non-RT RIC 115 may be configured to include a logical function that enables non- real-time control and optimization of RAN elements and resources, artificial intelligence (Al) / machine learning (ML) (AI/ML) workflows including model training and updates, or policy-based guidance of applications/features in the Near-RT RIC 125. The Non-RT RIC 115 may be coupled to or communicate with (such as via an Al interface) the Near- RT RIC 125. The Near-RT RIC 125 may be configured to include a logical function that enables near- real-time control and optimization of RAN elements and resources via data collection and actions over an interface (such as via an E2 interface) connecting one or more CUs 110, one or more DUs 130, or both, as well as an O-eNB, with the Near-RT RIC 125.

[0042] In some implementations, to generate AI/ML models to be deployed in the Near-RT RIC 125, the Non-RT RIC 115 may receive parameters or external enrichment information from external servers. Such information may be utilized by the Near-RT RIC 125 and may be received at the SMO Framework 105 or the Non-RT RIC 115 from non-network data sources or from network functions. In some examples, the Non-RT RIC 115 or the Near-RT RIC 125 may be configured to tune RAN behavior or performance. For example, the Non-RT RIC 115 may monitor long-term trends and patterns for performance and employ AI/ML models to perform corrective actions through the SMO Framework 105 (such as reconfiguration via 01) or via creation of RAN management policies (such as Al policies).

[0043] At least one of the CU 110, the DU 130, and the RU 140 may be referred to as a base station 102. Accordingly, a base station 102 may include one or more of the CU 110, the DU 130, and the RU 140 (each component indicated with dotted lines to signify that each component may or may not be included in the base station 102). The base station 102 provides an access point to the core network 120 for a UE 104. The base station 102 may include macrocells (high power cellular base station) and/or small cells (low power cellular base station). The small cells include femtocells, picocells, and microcells. A network that includes both small cell and macrocells may be known as a heterogeneous network. A heterogeneous network may also include Home Evolved Node Bs (eNBs) (HeNBs), which may provide service to a restricted group known as a closed subscriber group (CSG). The communication links between the RUs 140 and the UEs 104 may include uplink (UL) (also referred to as reverse link) transmissions from a UE 104 to an RU 140 and/or downlink (DL) (also referred to as forward link) transmissions from an RU 140 to a UE 104. The communication links may use multiple-input and multipleoutput (MIMO) antenna technology, including spatial multiplexing, beamforming, and/or transmit diversity. The communication links may be through one or more carriers. The base station 102 / UEs 104 may use spectrum up to K MHz (e.g., 5, 10, 15, 20, 100, 400, etc. MHz) bandwidth per carrier allocated in a carrier aggregation of up to a total of x MHz (x component carriers) used for transmission in each direction. The carriers may or may not be adjacent to each other. 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). The component carriers 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).

[0044] Certain UEs 104 may communicate with each other using device-to-device (D2D) communication link 158. The D2D communication link 158 may use the DL/UL wireless wide area network (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). D2D communication may be through a variety of wireless D2D communications systems, such as for example, Bluetooth™ (Bluetooth is a trademark of the Bluetooth Special Interest Group (SIG)), Wi-Fi™ (Wi-Fi is a trademark of the Wi-Fi Alliance) based on the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard, LIE, or NR.

[0045] The wireless communications system may further include a Wi-Fi AP 150 in communication with UEs 104 (also referred to as Wi-Fi stations (STAs)) via communication link 154, e.g., in a 5 GHz unlicensed frequency spectrum or the like. When communicating in an unlicensed frequency spectrum, the UEs 104 / AP 150 may perform a clear channel assessment (CCA) prior to communicating in order to determine whether the channel is available.

[0046] The electromagnetic spectrum is often subdivided, based on frequency/wavelength, into various classes, bands, channels, etc. In 5G NR, two initial operating bands have been identified as frequency range designations FR1 (410 MHz - 7.125 GHz) and FR2 (24.25 GHz - 52.6 GHz). Although a portion of FR1 is greater than 6 GHz, FR1 is often referred to (interchangeably) as a “sub-6 GHz” band in various documents and articles. A similar nomenclature issue sometimes occurs with regard to FR2, which is often referred to (interchangeably) as a “millimeter wave” band in documents and articles, despite being different from the extremely high frequency (EHF) band (30 GHz - 300 GHz) which is identified by the International Telecommunications Union (ITU) as a “millimeter wave” band.

[0047] The frequencies between FR1 and FR2 are often referred to as mid-band frequencies. Recent 5G NR studies have identified an operating band for these mid-band frequencies as frequency range designation FR3 (7.125 GHz - 24.25 GHz). Frequency bands falling within FR3 may inherit FR1 characteristics and/or FR2 characteristics, and thus may effectively extend features of FR1 and/or FR2 into mid-band frequencies. In addition, higher frequency bands are currently being explored to extend 5G NR operation beyond 52.6 GHz. For example, three higher operating bands have been identified as frequency range designations FR2-2 (52.6 GHz - 71 GHz), FR4 (71 GHz - 114.25 GHz), and FR5 (114.25 GHz - 300 GHz). Each of these higher frequency bands falls within the EHF band.

[0048] With the above aspects in mind, unless specifically stated otherwise, the term “sub-6 GHz” or the like if used herein may broadly represent frequencies that may be less than 6 GHz, may be within FR1, or may include mid-band frequencies. Further, unless specifically stated otherwise, the term “millimeter wave” or the like if used herein may broadly represent frequencies that may include mid-band frequencies, may be within FR2, FR4, FR2-2, and/or FR5, or may be within the EHF band.

[0049] The base station 102 and the UE 104 may each include a plurality of antennas, such as antenna elements, antenna panels, and/or antenna arrays to facilitate beamforming. The base station 102 may transmit a beamformed signal 182 to the UE 104 in one or more transmit directions. The UE 104 may receive the beamformed signal from the base station 102 in one or more receive directions. The UE 104 may also transmit a beamformed signal 184 to the base station 102 in one or more transmit directions. The base station 102 may receive the beamformed signal from the UE 104 in one or more receive directions. The base station 102 / UE 104 may perform beam training to determine the best receive and transmit directions for each of the base station 102/ UE 104. The transmit and receive directions for the base station 102 may or may not be the same. The transmit and receive directions for the UE 104 may or may not be the same.

[0050] The base station 102 may include and/or be referred to as a gNB, Node B, 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 TRP, network node, network entity, network equipment, or some other suitable terminology. The base station 102 can be implemented as an integrated access and backhaul (IAB) node, a relay node, a sidelink node, an aggregated (monolithic) base station with a baseband unit (BBU) (including a CU and a DU) and an RU, or as a disaggregated base station including one or more of a CU, a DU, and/or an RU. The set of base stations, which may include disaggregated base stations and/or aggregated base stations, may be referred to as next generation (NG) RAN (NG-RAN).

[0051] The core network 120 may include an Access and Mobility Management Function (AMF)

161, a Session Management Function (SMF) 162, a User Plane Function (UPF) 163, a Unified Data Management (UDM) 164, one or more location servers 168, and other functional entities. The AMF 161 is the control node that processes the signaling between the UEs 104 and the core network 120. The AMF 161 supports registration management, connection management, mobility management, and other functions. The SMF 162 supports session management and other functions. The UPF 163 supports packet routing, packet forwarding, and other functions. The UDM 164 supports the generation of authentication and key agreement (AKA) credentials, user identification handling, access authorization, and subscription management. The one or more location servers 168 are illustrated as including a Gateway Mobile Location Center (GMLC) 165 and a Location Management Function (LMF) 166. However, generally, the one or more location servers 168 may include one or more location/positioning servers, which may include one or more of the GMLC 165, the LMF 166, a position determination entity (PDE), a serving mobile location center (SMLC), a mobile positioning center (MPC), or the like. The GMLC 165 and the LMF 166 support UE location services. The GMLC 165 provides an interface for clients/applications (e.g., emergency services) for accessing UE positioning information. The LMF 166 receives measurements and assistance information from the NG-RAN and the UE 104 via the AMF 161 to compute the position of the UE 104. The NG-RAN may utilize one or more positioning methods in order to determine the position of the UE 104. Positioning the UE 104 may involve signal measurements, a position estimate, and an optional velocity computation based on the measurements. The signal measurements may be made by the UE 104 and/or the base station 102 serving the UE 104. The signals measured may be based on one or more of a satellite positioning system (SPS) 170 (e.g., one or more of a Global Navigation Satellite System (GNSS), global position system (GPS), non-terrestrial network (NTN), or other satellite position/location system), LIE signals, wireless local area network (WLAN) signals, Bluetooth signals, a terrestrial beacon system (TBS), sensor-based information (e.g., barometric pressure sensor, motion sensor), NR enhanced cell ID (NR E-CID) methods, NR signals (e.g., multi-round trip time (Multi-RTT), DL angle-of-departure (DL-AoD), DL time difference of arrival (DL-TDOA), UL time difference of arrival (UL-TDOA), and UL angle-of-arrival (UL-AoA) positioning), and/or other systems/signals/sensors.

[0052] Examples of UEs 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., 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 healthcare device, an implant, a sensor/actuator, a display, or any other similar functioning device. Some of the UEs 104 may be referred to as loT devices (e.g., parking meter, gas pump, toaster, vehicles, heart monitor, etc.). The 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 communications 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. In some scenarios, the term UE may also apply to one or more companion devices such as in a device constellation arrangement. One or more of these devices may collectively access the network and/or individually access the network.

[0053] Referring again to FIG. 1, in certain aspects, the UE 104 may have a time-space beam index component 198 that may be configured to receive, via a first MIB of a first SSB, a first spatial order index value and obtain, based on the first spatial order index value, RMSI associated with cell acquisition. In certain aspects, the base station 102 may have a time-space beam index component 199 that may be configured to simultaneously transmit a plurality of SSBs, where each SSB in the plurality of SSBs includes a different spatial order index value in a plurality of spatial order index values, and obtain, based on a first spatial order index value in the plurality of spatial order index values included in a first SSB in the plurality of SSBs, at least one RACH message associated with a cell acquisition. Although the following description may be focused 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. [0054] FIG. 2A is a diagram 200 illustrating an example of a first subframe within a 5G NR frame structure. FIG. 2B is a diagram 230 illustrating an example of DL channels within a 5G NR subframe. FIG. 2C is a diagram 250 illustrating an example of a second subframe within a 5G NR frame structure. FIG. 2D is a diagram 280 illustrating an example of UL channels within a 5G NR subframe. The 5G NR frame structure may be frequency division duplexed (FDD) in which for a particular set of subcarriers (carrier system bandwidth), subframes within the set of subcarriers are dedicated for either DL or UL, or may be time division duplexed (TDD) in which for a particular set of subcarriers (carrier system bandwidth), subframes within the set of subcarriers are dedicated for both DL and UL. In the examples provided by FIGs. 2A, 2C, the 5G NR frame structure is assumed to be TDD, with subframe 4 being configured with slot format 28 (with mostly DL), where D is DL, U is UL, and F is flexible for use between DL/UL, and subframe 3 being configured with slot format 1 (with all UL). While subframes 3, 4 are shown with slot formats 1, 28, respectively, any particular subframe may be configured with any of the various available slot formats 0-61. Slot formats 0, 1 are all DL, UL, respectively. Other slot formats 2-61 include a mix of DL, UL, and flexible symbols. UEs are configured with the slot format (dynamically through DL control information (DCI), or semi-statically/statically through radio resource control (RRC) signaling) through a received slot format indicator (SFI). Note that the description infra applies also to a 5G NR frame structure that is TDD.

[0055] FIGs. 2A-2D illustrate a frame structure, and the aspects of the present disclosure may be applicable to other wireless communication technologies, which may have a different frame structure and/or different channels. A frame (10 ms) may be divided into 10 equally sized subframes (1 ms). Each subframe may include one or more time slots. Subframes may also include mini-slots, which may include 7, 4, or 2 symbols. Each slot may include 14 or 12 symbols, depending on whether the cyclic prefix (CP) is normal or extended. For normal CP, each slot may include 14 symbols, and for extended CP, each slot may include 12 symbols. The symbols on DL may be CP orthogonal frequency division multiplexing (OFDM) (CP-OFDM) symbols. The symbols on UL may be CP-OFDM symbols (for high throughput scenarios) or discrete Fourier transform (DFT) spread OFDM (DFT-s-OFDM) symbols (for power limited scenarios; limited to a single stream transmission). The number of slots within a subframe is based on the CP and the numerology. The numerology defines the subcarrier spacing (SCS) (see Table 1). The symbol length/duration may scale with 1/SCS.

Table 1: Numerology, SCS, and CP

[0056] For normal CP (14 symbols/slot), different numerologies p 0 to 4 allow for 1, 2, 4, 8, and 16 slots, respectively, per subframe. For extended CP, the numerology 2 allows for 4 slots per subframe. Accordingly, for normal CP and numerology p, there are 14 symbols/slot and 2'^Ll slots/subframe. The subcarrier spacing may be equal to 2 * 15 kHz, where p is the numerology 0 to 4. As such, the numerology p=0 has a subcarrier spacing of 15 kHz and the numerology p=4 has a subcarrier spacing of 240 kHz. The symbol length/duration is inversely related to the subcarrier spacing. FIGs. 2A-2D provide an example of normal CP with 14 symbols per slot and numerology p=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 ps. Within a set of frames, there may be one or more different bandwidth parts (BWPs) (see FIG. 2B) that are frequency division multiplexed. Each BWP may have a particular numerology and CP (normal or extended).

[0057] A resource grid may be used to represent the frame structure. Each time slot includes a resource block (RB) (also referred to as physical RBs (PRBs)) that extends 12 consecutive subcarriers. The resource grid is divided into multiple resource elements (REs). The number of bits carried by each RE depends on the modulation scheme. [0058] As illustrated in FIG. 2A, some of the REs carry reference (pilot) signals (RS) for the UE. The RS may include demodulation RS (DM-RS) (indicated as R for one particular configuration, but other DM-RS configurations are possible) and channel state information reference signals (CSI-RS) for channel estimation at the UE. The RS may also include beam measurement RS (BRS), beam refinement RS (BRRS), and phase tracking RS (PT-RS).

[0059] FIG. 2B illustrates an example of various DL channels within a subframe of a frame. The physical downlink control channel (PDCCH) carries DCI within 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. A PDCCH within one BWP may be referred to as a control resource set (CORESET). A UE is configured to monitor PDCCH candidates in a PDCCH search space (e.g., common search space, UE-specific search space) during PDCCH monitoring occasions on the CORESET, where the PDCCH candidates have different DCI formats and different aggregation levels. Additional BWPs may be located at greater and/or lower frequencies across the channel bandwidth. A primary synchronization signal (PSS) may be within symbol 2 of particular subframes of a frame. The PSS is used by a UE 104 to determine subframe/symbol timing and a physical layer identity. A secondary synchronization signal (SSS) may be within symbol 4 of particular subframes of a frame. The SSS is used by a UE to determine a physical layer cell identity group number and radio frame timing. Based on the physical layer identity and the physical layer cell identity group number, the UE can determine a physical cell identifier (PCI). Based on the PCI, the UE can determine the locations of the DM-RS. The physical broadcast channel (PBCH), which carries a master information block (MIB), may be logically grouped with the PSS and SSS to form a synchronization signal (SS)/PBCH block (also referred to as SS block (SSB)). The MIB provides a number of RBs in the system bandwidth and a system frame number (SFN). The physical downlink shared channel (PDSCH) carries user data, broadcast system information not transmitted through the PBCH such as system information blocks (SIBs), and paging messages.

[0060] As illustrated in FIG. 2C, some of the REs carry DM-RS (indicated as R for one particular configuration, but other DM-RS configurations are possible) for channel estimation at the base station. The UE may transmit DM-RS for the physical uplink control channel (PUCCH) and DM-RS for the physical uplink shared channel (PUSCH). The PUSCH DM-RS may be transmitted in the first one or two symbols of the PUSCH. The PUCCH DM-RS may be transmitted in different configurations depending on whether short or long PUCCHs are transmitted and depending on the particular PUCCH format used. The UE may transmit sounding reference signals (SRS). The SRS may be transmitted in the last symbol of a subframe. The SRS may have a comb structure, and a UE may transmit SRS on one of the combs. The SRS may be used by a base station for channel quality estimation to enable frequency-dependent scheduling on the UL.

[0061] FIG. 2D illustrates an example of various UL channels within a subframe of a frame. The PUCCH may be located as indicated in one configuration. The PUCCH carries uplink control information (UCI), such as scheduling requests, a channel quality indicator (CQI), a precoding matrix indicator (PMI), a rank indicator (RI), and hybrid automatic repeat request (HARQ) acknowledgment (ACK) (HARQ-ACK) feedback (i.e., one or more HARQ ACK bits indicating one or more ACK and/or negative ACK (NACK)). The PUSCH carries data, and may additionally be used to carry a buffer status report (BSR), a power headroom report (PHR), and/or UCI.

[0062] FIG. 3 is a block diagram of a base station 310 in communication with a UE 350 in an access network. In the DL, Internet protocol (IP) packets may be provided to a controller/processor 375. The controller/processor 375 implements layer 3 and layer 2 functionality. 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 functionality associated with broadcasting of system information (e.g., MIB, SIBs), 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 functionality associated with header compression / decompression, security (ciphering, deciphering, integrity protection, integrity verification), and handover support functions; RLC layer functionality associated with the transfer of upper layer packet data units (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 functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto transport blocks (TBs), demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority handling, and logical channel prioritization.

[0063] The transmit (TX) processor 316 and the receive (RX) processor 370 implement layer 1 functionality associated with various signal processing functions. Layer 1 , which includes a physical (PHY) layer, may include error detection on the transport channels, forward error correction (FEC) coding/decoding of the transport channels, interleaving, rate matching, mapping onto physical channels, modulation/demodulation of physical channels, and MIMO antenna processing. The TX processor 316 handles mapping to signal constellations 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 may then be split into parallel streams. Each stream may then be mapped to an OFDM subcarrier, multiplexed with a reference signal (e.g., pilot) in the time 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 scheme, as well as for spatial processing. The channel estimate may be derived from a reference signal and/or channel condition feedback transmitted by the UE 350. Each spatial stream may then be provided to a different antenna 320 via a separate transmitter 318Tx. Each transmitter 318Tx may modulate a radio frequency (RF) carrier with a respective spatial stream for transmission.

[0064] At the UE 350, each receiver 354Rx receives a signal through its respective antenna 352. Each receiver 354Rx recovers information modulated onto an RF carrier and provides the information to the receive (RX) processor 356. The TX processor 368 and the RX processor 356 implement layer 1 functionality associated with various signal processing functions. The RX processor 356 may perform spatial processing on the information to recover any spatial streams destined for the UE 350. If multiple spatial streams are destined for the UE 350, they may be combined by the RX processor 356 into a single OFDM symbol stream. 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 on each subcarrier, and the reference signal, are recovered and demodulated by determining the most likely signal constellation points transmitted by the base station 310. These soft decisions may be based on channel estimates computed by the channel estimator 358. The soft decisions are then decoded and deinterleaved to recover the data and control signals that were originally transmitted by the base station 310 on the physical channel. The data and control signals are then provided to the controller/processor 359, which implements layer 3 and layer 2 functionality.

[0065] The controller/processor 359 can be associated with at least one memory 360 that stores program codes and data. The at least one 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, deciphering, header decompression, and control signal processing to recover IP packets. The controller/processor 359 is also responsible for error detection using an ACK and/or NACK protocol to support HARQ operations.

[0066] Similar to the functionality described in connection with the DL transmission by the base station 310, the controller/processor 359 provides RRC layer functionality associated with system information (e.g., MIB, SIBs) acquisition, RRC connections, and measurement reporting; PDCP layer functionality associated with header compression / decompression, and security (ciphering, deciphering, integrity protection, integrity verification); RLC layer functionality associated with the transfer of upper layer PDUs, error correction through ARQ, concatenation, segmentation, and reassembly of RLC SDUs, re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto TBs, demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority handling, and logical channel prioritization.

[0067] Channel estimates derived by a channel estimator 358 from a reference signal or feedback transmitted by the base station 310 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 respective spatial stream for transmission.

[0068] The UL transmission is processed at the base station 310 in a manner similar to that described in connection with the receiver function at the UE 350. 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.

[0069] The controller/processor 375 can be associated with at least one memory 376 that stores program codes and data. The at least one 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, deciphering, header decompression, control signal processing to recover IP packets. The controller/processor 375 is also responsible for error detection using an ACK and/or NACK protocol to support HARQ operations.

[0070] At least one of the TX processor 368, the RX processor 356, and the controller/processor 359 may be configured to perform aspects in connection with the time-space beam index component 198 of FIG. 1.

[0071] At least one of the TX processor 316, the RX processor 370, and the controller/processor 375 may be configured to perform aspects in connection with the time-space beam index component 199 of FIG. 1.

[0072] In some aspects of wireless communication, a base station may transmit SSBs in association with initial cell detection and/or beam management. FIG. 4 is a first diagram 400 illustrating locations within a slot for SSBs associated with a first SCS in accordance with some aspects of the disclosure. Within an SSB burst, the maximum number of possible candidate SSB locations may be a value (“L”) that depends on the carrier frequency. For example, for carrier frequencies up to 3 GHz, L may take the value 4; for carrier frequencies between 3 GHz and 7 GHz, L may take the value 8; and for carrier frequencies from 7 GHz to 52.6 GHz (or 7 GHz and above), L may take the value 64 as illustrated in diagram 400.

[0073] Diagram 400 illustrates a pattern and/or distribution of SSB opportunities and/or SSB locations within a slot for a high-frequency SCS (e.g., 120 kHz SCS). As illustrated in diagram 400, there are 5 subframes (e.g., subframe 410) corresponding to 40 slots (e.g., including slot 420) that are candidates for including one or more SSBs (for a maximum of 64 SSB opportunities/locations per SSB burst). The 40 slots (where a slot is 0.125 ms and a subframe is 1 ms for the 120 kHz SCS), in some aspects, may span a first 5 ms within a first half-frame in a set of 4 half frames (e.g., a first 5 ms window in a 20 ms time period). The SSB opportunity/location pattern 430 illustrates that each of the 40 candidate slots may include 14 OFDM symbols and that a first slot in a pair of slots may include symbols 4-7 as a first SSB opportunity/location (e.g., SSBo) and symbols 8-11 as a second SSB opportunity/location (e.g., SSBi). Similarly, the second slot may include symbols 16-19 as a third SSB opportunity/location (e.g., SSB2) and symbols 20-23 as a fourth SSB opportunity/location (e.g., SSB3). In some aspects, positions for the SSB opportunities may be different without changing the relevant characteristics of the SSB opportunities.

[0074] In some aspects, each SSB may be associated with an SSB index indicating a position (e.g., a slot and symbol) of the SSB within the set of slots and/or within the 20 ms repetition window. The SSB index, in some aspects, may be implicitly broadcast by the SSB-PBCH DMRS sequence cyclic shift (e.g., a 3 -bit value) and explicitly as a bitfield in the MIB payload (e.g., an additional 3 bits). In some aspects, upon initial cell search, a UE may use the beam index (e.g., the combination of the 3 -bit value associated with the SSB-PBCH DMRS sequence cyclic shift and the 3 bit value in the MIB payload) to determine a slot number (e.g., a position in time within the 20 ms repetition window). The beam index, in some aspects, may be used for calculating and/or determining an associated SIB1, as well as RACH and paging occasions.

[0075] For example, a base station 402 may transmit a first SSB transmission along a first beam 440 and/or direction including an SSB index indicating that the first SSB transmission is associated with the first SSB opportunity/location (e.g., SSBo). The base station may, during the second SSB opportunity/location (e.g., SSBi), transmit a second SSB transmission along a second beam 441 and/or direction including an SSB index indicating that the second SSB transmission is associated with the second SSB opportunity/location (e.g., SSBi). Similar SSB transmissions along a third beam 442 and/or directions and along a fourth beam and/or direction 443 may be made during the third and fourth SSB opportunities/locations (e.g., SSB2 and SSB3), respectively.

[0076] For higher frequency bands (e.g., FR4 and FR5), beams may become narrower to allow sufficient cell coverage due to higher propagation losses. With narrower beams, more beams may be used to provide coverage for a same angular area. However, the use of more beams, in some aspects, may be associated with a larger number of broadcasting resources (e.g., SSB transmission occasions, SIB1, paging occasions, and, to some extent, RACH occasions). The larger number of broadcasting resources may increase an overhead and/or a time associated with transmitting the larger number of SSB transmission occasions.

[0077] Various aspects relate generally to increasing a beam index by using time-space indexing. Some aspects more specifically relate to the use of a larger number of narrower beams in a high frequency band by transmitting multiple spatial beams (e.g., in different directions) in a same time resource and identifying the spatial beams using an enhanced beam index signaled within a MIB. In some examples, a UE may be configured to receive, via a first MIB of a first SSB, a first spatial order index value and obtain, based on the first spatial order index value, RMSI associated with cell acquisition. A network device such as a base station, in some aspects, may be configured to simultaneously transmit a plurality of SSBs, where each SSB in the plurality of SSBs includes a different spatial order index value in a plurality of spatial order index values, and obtain, based on a first spatial order index value in the plurality of spatial order index values included in a first SSB in the plurality of SSBs, at least one RACH message associated with a cell acquisition.

[0078] Particular aspects of the subject matter described in this disclosure can be implemented to realize one or more of the following potential advantages. In some examples, by using time-space indexing, the described techniques can be used to include a higher number of SSB beams per burst, facilitating narrower beams for better cell coverage. [0079] FIG. 5 is a diagram 500 illustrating the use of a time-space beam index in accordance with some aspects of the disclosure. Diagram 500 illustrates an SSB opportunity/location pattern (e.g., corresponding to the SSB opportunity/location pattern 430 of FIG. 4) in a set of symbols. The set of symbols, in some aspects, may be associated with multiple spatial order index values (which may alternatively be referred to as spatial order values, spatial indexes, spatial index values, or similar terms). For example, the set of symbols may have a first association 501 with a first spatial order index (“0”), a second association with a second spatial order index (“1”), a third association with a third spatial order index (“2”), and a fourth association 504 with a fourth spatial order index (“3”).

[0080] Based on the SSB index (e.g., SSBo 510, SSBi 520, SSB₂ 530, and SSB₃ 540) associated with the set of SSB opportunities/locations and a spatial order index, a larger number of uniquely identified SSBs may be transmitted over the set of SSB opportunities/locations. [0081] For example, a base station 502 may transmit a first plurality of SSB transmissions 515 along a first plurality of beams and/or directions (e.g., a first beam 511, a second beam 512, a third beam 513, and a fourth beam 514) including an SSB index indicating that the first plurality of SSB transmissions 515 is associated with the first SSB opportunity/location (e.g., SSBo 510). The first plurality of SSB transmissions 515 may include, e.g., in an additional field in an MIB, a unique index value associated with the spatial order index such that the simultaneously transmitted first plurality of SSB transmissions 515 are uniquely identifiable (e.g., by a time-space beam index SSBo.o, SSBi,o, SSB₂,o, and SSB₃,o 516 (indicating a time index of 0 and a spatial order index of 3)). The base station 502 may transmit a second plurality of SSB transmissions 525 along a second plurality of beams and/or directions (e.g., a first beam 521, a second beam 522, a third beam 523, and a fourth beam 524) including an SSB index indicating that the second plurality of SSB transmissions 525 is associated with the second SSB opportunity/location (e.g., SSBi 520). The second plurality of SSB transmissions 525 may include, e.g., in an additional field in an MIB, a unique index value associated with the spatial order index such that the simultaneously transmitted second plurality of SSB transmissions 525 are uniquely identifiable (e.g., by a time-space beam index SSBo,i, SSBi,i, SSB₂,I, and SSB₃,I). The base station 502 may transmit a third plurality of SSB transmissions 535 along a third plurality of beams and/or directions (e.g., a first beam 531, a second beam 532, a third beam 533, and a fourth beam 534) including an SSB index indicating that the third plurality of SSB transmissions 535 is associated with the third SSB opportunity /location (e.g., SSB2 530). The third plurality of SSB transmissions 535 may include, e.g., in an additional field in an MIB, a unique index value associated with the spatial order index such that the simultaneously transmitted third plurality of SSB transmissions 535 are uniquely identifiable (e.g., by a time-space beam index SSBo,2, SSBI,2, SSB2,2, and SSB3.2). The base station 502 may transmit a fourth plurality of SSB transmissions 545 along a fourth plurality of beams and/or directions (e.g., a first beam 541, a second beam 542, a third beam 543, and a fourth beam 544) including an SSB index indicating that the fourth plurality of SSB transmissions 545 is associated with the fourth SSB opportunity/location (e.g., SSB3 540). The fourth plurality of SSB transmissions 545 may include, e.g., in an additional field in an MIB, a unique index value associated with the spatial order index such that the simultaneously transmitted fourth plurality of SSB transmissions 545 are uniquely identifiable (e.g., by a time-space beam index SSBo,3, SSBI,3, SSB2.3, and SSB3.3). The time-space beam index, in some aspects, may be used to identify a quasi-co-location (QCL) with a reference signal.

[0082] In some aspects, the simultaneous SSB transmission may be associated with “orthogonal”

SSB beams and/or directions, where “orthogonal” SSB beams and/or directions are not expected to interfere with each other at a particular receiving wireless device (e.g., a particular UE). The maximum number of simultaneous SSB transmissions may, in some aspects, be based on the maximum number of SSB beams and/or directions that are expected to meet an orthogonality criteria and/or condition. The orthogonality criteria and/or condition, in some aspects, may be a threshold relative received power of other simultaneously SSB transmissions compared to a received power of the SSB transmission likely to be selected for communication.

[0083] For example, for a first SSB transmission associated with a line of sight (LOS) to a receiving UE, additional SSB transmissions associated with directions that are separated by at least a threshold angle (e.g., 0_th) may be associated with an expected received power below a threshold value compared to the expected received power of the first SSB p ■ transmission (e.g., a threshold power ratio measured in dB, P_th = — , V j #= i, where i is the spatial order index associated with the first (LOS) SSB transmission). Accordingly, the maximum number of simultaneous SSB transmissions may be based on the threshold angle (and the threshold power ratio used to determine the threshold angle). In some aspects, the size of a field (e.g., a number of bits) for specifying the spatial order index value may be based on the allowable (maximum) number of simultaneous SSB transmissions and/or a configured number of simultaneous SSB transmissions. The configured number of simultaneous SSB transmissions, in some aspects, may be determined based on the maximum number of possible candidate SSB locations (e.g., which may depend on a frequency range and/or SCS) and a number of beams and/or directions to scan during an SSB burst. For example, a 1 -bit spatial order index field may allow for 128 SSB transmissions in an SSB burst associated with a 120 kHz SCS (as illustrated in FIG. 4), while a 2-bit, or 3 -bit, spatial order index field would allow for 256, or 512, SSB transmissions in the SSB burst, respectively.

[0084] In some aspects, the base station 502 using the spatial ordered SSB beam transmission (with unique MIB per SSB beam) as described above may also transmit concurrent SIB1 and/or paging (with a same payload) on the same spatially ordered SSB beams (e.g., beams associated with the time beam index SSBo.o, SSBi,o, SSB2,o, and SSB₃,O; SSBo,i, SSB_U, SSB₂,I, and SSB₃,I; SSBo,2, SSBI,₂, SSB_2;2, and SSB_3J2; or SSBo,₃, SSBI,₃, SSB_2;3, and SSB_3J3). Accordingly, the SIB1 and/or paging scheduling and resource overhead (e.g., SIB1 transmission occasions and/or paging occasions) may not need to be different when using simultaneously transmitted spatial ordered SSB beams when compared to using individually transmitted SSBs without spatial ordering.

[0085] FIG. 6 is a call flow diagram 600 illustrating a method of using a time-space (or spatial) index in accordance with some aspects of the disclosure. The method is illustrated in relation to a base station 602 (e.g., as an example of a network device or network node that may include one or more components of a disaggregated base station) in communication with a UE 604 (e.g., as an example of a wireless device). The functions ascribed to the base station 602, in some aspects, may be performed by one or more components of a network entity, a network node, or a network device (a single network entity/node/device or a disaggregated network entity/node/device as described above in relation to FIG. 1). Similarly, the functions ascribed to the UE 604, in some aspects, may be performed by one or more components of a wireless device supporting communication with a network entity/node/device. Accordingly, references to “transmitting” in the description below may be understood to refer to a first component of the base station 602 (or the UE 604) outputting (or providing) an indication of the content of the transmission to be transmitted by a different component of the base station 602 (or the UE 604). Similarly, references to “receiving” in the description below may be understood to refer to a first component of the base station 602 (or the UE 604) receiving a transmitted signal and outputting (or providing) the received signal (or information based on the received signal) to a different component of the base station 602 (or the UE 604).

[0086] The base station 602 may transmit, and a UE 604 may receive, SSB time-space configuration 606. In some aspects, the SSB time-space configuration 606 may indicate a number of simultaneously transmitted SSBs (or a maximum number of simultaneously transmitted SSBs) associated with each SSB opportunity/location or SSB index (e.g., SSBo 510, SSBi 520, SSB2 530, and SSB3 540 of FIG. 5). In some aspects, the number of simultaneously transmitted SSBs may be indicated in an RRC parameter, e.g., ssb- perRACH-OccasionAndCB-Preamb/esPerSSB. For example, in some aspects, the maximum number of simultaneously transmitted SSBs may be indicated by a size of an MIB field (e.g., a spatial order field or a spatial order index field) for indicating a spatial order index (e.g., a spatial order index value), e.g., based on an indication of a particular MIB configuration and/or format. In some aspects, the SSB time-space configuration (e.g., the configuration and/or format of the MIB carrying the spatial order index value and/or the time-space SSB information) may be known or configured. For example, the UE 604 may be configured to assume a first SSB/MIB format (e.g., a format carrying the spatial order index information in a known number of bits) for a SCS at, or above, a threshold value (e.g., at, or above, 120 kHz), and to assume a second SSB/MIB format (e.g., a format not carrying the spatial order index information) for a SCS below the threshold (e.g., below 120 kHz).

[0087] Based on the SSB time-space configuration 606 (or a known and/or configured SSB timespace configuration), the base station 602 may transmit, and the UE 604 may receive at least in part, the SSBs within an SSB burst 608. Each SSB in the SSB burst 608, in some aspects, may include an SSB (time) index (e.g., in PBCH-DMRS cyclic shift and in the MIB payload) and an SSB spatial order value (a spatial order index) in the MIB pay load. In some aspects, each SSB transmission in one plurality of simultaneous SSB transmission in the SSB burst 608 (e.g., one of the first plurality of SSB transmissions 515, the second plurality of SSB transmissions 525, the third plurality of SSB transmissions 535, and/or the fourth plurality of SSB transmissions 545 of FIG. 5 that may be included in an SSB burst) may include a different spatial order index (or spatial order) value in a plurality of spatial order index values. The spatial order index value, in some aspects, may be included in a spatial order field of the MIB in each SSB transmission. As discussed in relation to FIG. 5 above, each SSB (or SSB transmission) in the plurality of (simultaneously transmitted) SSBs may be associated with a different transmission direction in a plurality of transmission directions associated with a same SSB time index, and each transmission direction in the plurality of transmission directions may be identified by a corresponding value in the plurality of spatial order index values. Similarly, each SSB in an SSB burst may be associated with a different transmission direction in a set of transmission directions covered in the SSB burst, and each transmission direction in the set of transmission directions may be identified by a corresponding value in the plurality of time-space index values (e.g., the plurality of unique combinations of the SSB time index and the spatial order index associated with the SSB burst).

[0088] The UE 604 may, at 610, determine, based on the received SSB(s) and/or MIB(s), resources to use for obtaining RMSI (e.g., time-and frequency resources and a beam direction associated with the received SSB(s) and/or MIB(s)). For example, the UE 604, may determine, based on the time-space index value (e.g., the combination of the time index and the spatial order index) associated with, or included in, a received SSB/MIB, a beam, a set of frequency resources (e.g., a frequency range), and/or a set of time resources (e.g., a set of symbols and/or slots) to use, or monitor, to receive the RMSI. In some aspects, the RMSI may be a SIB1, or other SIB.

[0089] The base station 602 may transmit, and the UE 604 may receive and/or obtain, RMSI associated with cell acquisition via a RMSI transmission in a set of RMSI transmissions 612. In some aspects, the base station 602 may simultaneously transmit, via the plurality of transmission directions (associated with simultaneously transmitted SSBs), the RMSI associated with the cell acquisition. For example, each plurality of simultaneous SSB transmissions, in some aspects, may be associated with (corresponding) simultaneous RMSI transmissions (e.g., RMSI transmission using a same, or overlapping, set of time resources based on the same orthogonality that was assumed for the SSB transmissions). [0090] The UE 604, may, at 614 decode the received RMSI transmission (e.g., obtain the RMSI) and determine RACH resources (e.g., frequency and time resources as well as candidate preambles). In some aspects, the RACH resources may be a RACH occasion (RO) and the RACH preamble may be determined at 614 based on a set of preambles associated with the first spatial order index value and the indication of the number of SSBs in the plurality of simultaneously transmitted SSBs. In some aspects, a RO timing may be the same for simultaneously transmitted (and spatially-ordered and/or spatially-indexed) SSBs. The RO timing, in some aspects, may be different for different spatially-ordered SSBs transmitted simultaneously.

[0091] Based on the RMSI, the UE 604, may transmit, and the base station 602 may receive, at least RACH message 616. For example, based on the RMSI from the set of RMSI transmissions 612, and the received SSB from the SSB burst 608, the UE 604, may select a RO and preamble to transmit a first message (e.g., Msgl) for an initial attachment (or RACH) procedure associated with cell acquisition. Based on receiving the RACH message 616, the base station 602 and the UE 604 may exchange additional communication 618 (e.g., additional messages associated with cell acquisition and, in some aspects, subsequent communication). In some aspects, the base station 602 may use a narrow beam 617 based on the RACH message 616 (e.g., based on the particular RO and preamble used, the base station 602 may determine that an SSB associated with the narrow beam 617 was received by the UE 604 and has been selected for future communication).

[0092] FIG. 7 is a flowchart 700 of a method of wireless communication. The method may be performed by a UE (e.g., the UE 104, 604; the apparatus 1104). In some aspects, the UE may obtain (and/or receive) an indication of a number of SSBs in a plurality of simultaneously transmitted SSBs. For example, referring to FIGs. 5 and 6, the UE 604 may receive SSB time-space configuration 606 indicating the number (e.g., four) of simultaneously transmitted SSBs (e.g., SSB transmissions associated with a first beam 511, a second beam 512, a third beam 513, or a fourth beam 514 of the first plurality of SSB transmissions 515) associated with each SSB (time) index.

[0093] At 704, the UE may receive, via a first MIB of a first SSB, a first spatial order index value. For example, 704 may be performed by application processor(s) 1106, cellular baseband processor(s) 1124, transceiver(s) 1122, antenna(s) 1180, and/or time-space beam index component 198 of FIG. 11. In some aspects, the first spatial order index value may be included in a spatial order field of the first MIB. The first SSB, in some aspects, may be one of a plurality of simultaneously transmitted SSBs, and each SSB in the plurality of simultaneously transmitted SSBs may include a different MIB from a plurality of MIBs. The first MIB, in some aspects, may be one of the plurality of MIBs and each MIB of the plurality of MIBs may include a different spatial order index value. In some aspects, each SSB in the plurality of simultaneously transmitted SSBs may be associated with a different transmission direction in a plurality of transmission directions, and each transmission direction in the plurality of transmission directions may be identified by a corresponding value of the different spatial order index values. For example, referring to FIGs. 5 and 6, the UE 604 may receive an SSB from a plurality of simultaneously transmitted SSBs in the SSB burst 608 (e.g., an SSB transmission associated with one of a first beam 511, a second beam 512, a third beam 513, or a fourth beam 514 of the first plurality of SSB transmissions 515, an SSB transmission associated with one of a first beam 521, a second beam 522, a third beam 523, or a fourth beam 524 of the second plurality of SSB transmissions 525, an SSB transmission associated with one of a first beam 531, a second beam 532, a third beam 533, or a fourth beam 534 of the third plurality of SSB transmissions 535, and/or an SSB transmission associated with one of a first beam 541, a second beam 542, a third beam 543, or a fourth beam 544 of the fourth plurality of SSB transmissions 545).

[0094] At 706, the UE may obtain, based on the first spatial order index value, RMSI associated with cell acquisition. For example, 706 may be performed by application processor(s) 1106, cellular baseband processor(s) 1124, transceiver(s) 1122, antenna(s) 1180, and/or time-space beam index component 198 of FIG. 11. The RMSI, in some aspects, may be transmitted in a direction associated with the first SSB and/or MIB. For example, referring to FIGs. 5 and 6, the UE 604 may, based on a time-space index associated with a received SSB transmission (e.g., SSBo,3 516 indicating a time index of 0 and a spatial order index of 3), receive and/or obtain RMSI associated with cell acquisition via a RMSI transmission in a set of RMSI transmissions 612 and may, at 614 decode the received RMSI transmission (e.g., obtain the RMSI) and determine RACH resources (e.g., frequency and time resources as well as candidate preambles).

[0095] In some aspects, the UE may transmit, based on the first spatial order index value and the RMSI, at least one RACH message associated with the cell acquisition. In some aspects, transmitting the at least one RACH message may include transmitting the at least one RACH message via a first RO based on the first spatial order index value and the indication of the number of SSBs in the plurality of simultaneously transmitted SSBs. The at least one RACH message, in some aspects, may include a preamble in a set of preambles associated with the first spatial order index value and the indication of the number of SSBs in the plurality of simultaneously transmitted SSBs. In some aspects, the set of preambles may be based on the number of SSBs in the plurality of simultaneously transmitted SSBs. For example, referring to FIGs. 5 and 6, the UE 604 may, transmit the RACH message 616, at an RO and using a preamble, based on the SSB time-space configuration 606, a time-space index associated with a received SSB transmission (e.g., SSBs.o 516 indicating a time index of 0 and a spatial order index of 3), the RMSI associated with cell acquisition via the RMSI transmission in a set of RMSI transmissions 612, and the decoding at 614 of the received RMSI transmission and determine RACH resources (e.g., frequency and time resources as well as candidate preambles).

[0096] FIG. 8 is a flowchart 800 of a method of wireless communication. The method may be performed by a UE (e.g., the UE 104, 604; the apparatus 1104). At 802, the UE may obtain (and/or receive) an indication of a number of SSBs in a plurality of simultaneously transmitted SSBs. For example, 802 may be performed by application processor(s) 1106, cellular baseband processor(s) 1124, transceiver(s) 1122, antenna(s) 1180, and/or timespace beam index component 198 of FIG. 11. For example, referring to FIGs. 5 and 6, the UE 604 may receive SSB time-space configuration 606 indicating the number (e.g., four) of simultaneously transmitted SSBs (e.g., SSB transmissions associated with a first beam 511, a second beam 512, a third beam 513, or a fourth beam 514 of the first plurality of SSB transmissions 515) associated with each SSB (time) index. [0097] At 804, the UE may receive, via a first MIB of a first SSB, a first spatial order index value. For example, 804 may be performed by application processor(s) 1106, cellular baseband processor(s) 1124, transceiver(s) 1122, antenna(s) 1180, and/or time-space beam index component 198 of FIG. 11. In some aspects, the first spatial order index value may be included in a spatial order field of the first MIB. The first SSB, in some aspects, may be one of a plurality of simultaneously transmitted SSBs, and each SSB in the plurality of simultaneously transmitted SSBs may include a different MIB from a plurality of MIBs. The first MIB, in some aspects, may be one of the plurality of MIBs and each MIB of the plurality of MIBs may include a different spatial order index value. In some aspects, each SSB in the plurality of simultaneously transmitted SSBs may be associated with a different transmission direction in a plurality of transmission directions, and each transmission direction in the plurality of transmission directions may be identified by a corresponding value of the different spatial order index values. For example, referring to FIGs. 5 and 6, the UE 604 may receive an SSB from a plurality of simultaneously transmitted SSBs in the SSB burst 608 (e.g., an SSB transmission associated with one of a first beam 511, a second beam 512, a third beam 513, or a fourth beam 514 of the first plurality of SSB transmissions 515, an SSB transmission associated with one of a first beam 521, a second beam 522, a third beam 523, or a fourth beam 524 of the second plurality of SSB transmissions 525, an SSB transmission associated with one of a first beam 531, a second beam 532, a third beam 533, or a fourth beam 534 of the third plurality of SSB transmissions 535, and/or an SSB transmission associated with one of a first beam 541, a second beam 542, a third beam 543, or a fourth beam 544 of the fourth plurality of SSB transmissions 545).

[0098] At 806, the UE may obtain, based on the first spatial order index value, RMSI associated with cell acquisition. For example, 806 may be performed by application processor(s) 1106, cellular baseband processor(s) 1124, transceiver(s) 1122, antenna(s) 1180, and/or time-space beam index component 198 of FIG. 11. The RMSI, in some aspects, may be transmitted in a direction associated with the first SSB and/or MIB. For example, referring to FIGs. 5 and 6, the UE 604 may, based on a time-space index associated with a received SSB transmission (e.g., SSBs.o 516 indicating a time index of 0 and a spatial order index of 3), receive and/or obtain RMSI associated with cell acquisition via a RMSI transmission in a set of RMSI transmissions 612 and may, at 614 decode the received RMSI transmission (e.g., obtain the RMSI) and determine RACH resources (e.g., frequency and time resources as well as candidate preambles).

[0099] At 808, the UE may transmit, based on the first spatial order index value and the RMSI, at least one RACH message associated with the cell acquisition. In some aspects, transmitting the at least one RACH message at 808 may include transmitting, at 809, the at least one RACH message via a first RO based on the first spatial order index value and the indication of the number of SSBs in the plurality of simultaneously transmitted SSBs. For example, 808 and 809 may be performed by application processor(s) 1106, cellular baseband processor(s) 1124, transceiver(s) 1122, antenna(s) 1180, and/or time-space beam index component 198 of FIG. 11. The at least one RACH message, in some aspects, may include a preamble in a set of preambles associated with the first spatial order index value and the indication of the number of SSBs in the plurality of simultaneously transmitted SSBs. In some aspects, the set of preambles may be based on the number of SSBs in the plurality of simultaneously transmitted SSBs. For example, referring to FIGs. 5 and 6, the UE 604 may, transmit the RACH message 616, at an RO and using a preamble, based on the SSB time-space configuration 606, a time-space index associated with a received SSB transmission (e.g., SSBo,3 516 indicating a time index of 0 and a spatial order index of 3), the RMSI associated with cell acquisition via the RMSI transmission in a set of RMSI transmissions 612, and the decoding at 614 of the received RMSI transmission and determine RACH resources (e.g., frequency and time resources as well as candidate preambles).

[0100] FIG. 9 is a flowchart 900 of a method of wireless communication. The method may be performed by a base station (e.g., the base station 102, 402, 502, 602; the network entity 1102, 1202). In some aspects, the base station may transmit an indication of the number of SSBs in a plurality of SSBs. For example, referring to FIGs. 5 and 6, the base station 602 may transmit SSB time-space configuration 606 indicating the number (e.g., four) of simultaneously transmitted SSBs associated with each SSB (time) index.

[0101] At 904, the base station may simultaneously transmit a plurality of SSBs. Each SSB in the plurality of SSBs, in some aspects, may include a different spatial order index value in a plurality of spatial order index values. For example, 904 may be performed by CU processor(s) 1212, DU processor(s) 1232, RU processor(s) 1242, transceiver(s) 1246, antenna(s) 1280, and/or time-space beam index component 199 of FIG. 12. In some aspects, a first spatial order index value may be included in a spatial order field of a first MIB included in a first SSB in the plurality of SSBs. Each SSB in the plurality of simultaneously transmitted SSBs, in some aspects, may include a different MIB from a plurality of MIBs. The first MIB, in some aspects, may be one of the plurality of MIBs and each MIB of the plurality of MIBs may include a different spatial order index value. In some aspects, each SSB in the plurality of simultaneously transmitted SSBs may be associated with a different transmission direction in a plurality of transmission directions, and each transmission direction in the plurality of transmission directions may be identified by a corresponding value of the different spatial order index values. For example, referring to FIGs. 5 and 6, the base station 502/602 may transmit a plurality of simultaneously transmitted SSBs in the SSB burst 608 (e.g., SSB transmissions associated with each of a first beam 511, a second beam 512, a third beam 513, and a fourth beam 514 of the first plurality of SSB transmissions 515, SSB transmissions associated with each of a first beam 521, a second beam 522, a third beam 523, and a fourth beam 524 of the second plurality of SSB transmissions 525, SSB transmissions associated with each of a first beam 531, a second beam 532, a third beam 533, and a fourth beam 534 of the third plurality of SSB transmissions 535, and SSB transmissions associated with one of a first beam 541, a second beam 542, a third beam 543, and a fourth beam 544 of the fourth plurality of SSB transmissions 545).

[0102] In some aspects, the base station may simultaneously transmit, via the plurality of transmission directions, RMSI associated with a cell acquisition. The RMSI, in some aspects, may include RMSI transmitted in a direction associated with the first SSB and/or MIB. For example, referring to FIGs. 5 and 6, the base station 502/602 may, transmit the set of RMSI transmissions 612.

[0103] At 908, the base station may obtain (and/or receive), based on a first spatial order index value in the plurality of spatial order index values included in a first SSB in the plurality of SSBs, at least one RACH message associated with a cell acquisition. In some aspects, obtaining the at least one RACH message at 908 may include receiving the at least one RACH message via a first RO based on the first spatial order index value and the indication of the number of SSBs in the plurality of (simultaneously transmitted) SSBs. For example, 908 may be performed by CU processor(s) 1212, DU processor(s) 1232, RU processor(s) 1242, transceiver(s) 1246, antenna(s) 1280, and/or time-space beam index component 199 of FIG. 12. The at least one RACH message, in some aspects, may include a preamble in a set of preambles associated with the first spatial order index value and the indication of the number of SSBs in the plurality of simultaneously transmitted SSBs. In some aspects, the set of preambles may be based on the number of SSBs in the plurality of simultaneously transmitted SSBs. For example, referring to FIGs. 5 and 6, the base station 502/602 may receive the RACH message 616, at an RO and including a preamble, based on the SSB time-space configuration 606, a time-space index associated with a SSB transmission received at the UE 604 (e.g., SSBs.o 516 indicating a time index of 0 and a spatial order index of 3), the RMSI associated with cell acquisition via a RMSI transmission received by the UE 604 in a set of RMSI transmissions 612, and the decoding by the UE 604 of the received RMSI transmission and determination of the RACH resources by the UE 604 (e.g., frequency and time resources as well as candidate preambles) at 614.

[0104] FIG. 10 is a flowchart 1000 of a method of wireless communication. The method may be performed by a base station (e.g., the base station 102, 402, 502, 602; the network entity 1102, 1202). At 1002, the base station may transmit an indication of the number of SSBs in a plurality of SSBs. For example, 1002 may be performed by CU processor(s) 1212, DU processor(s) 1232, RU processor(s) 1242, transceiver(s) 1246, antenna(s) 1280, and/or time-space beam index component 199 of FIG. 12. For example, referring to FIGs. 5 and 6, the base station 602 may transmit SSB time-space configuration 606 indicating the number (e.g., four) of simultaneously transmitted SSBs associated with each SSB (time) index.

[0105] At 1004, the base station may simultaneously transmit a plurality of SSBs. Each SSB in the plurality of SSBs, in some aspects, may include a different spatial order index value in a plurality of spatial order index values. For example, 1004 may be performed by CU processor(s) 1212, DU processor(s) 1232, RU processor(s) 1242, transceiver(s) 1246, antenna(s) 1280, and/or time-space beam index component 199 of FIG. 12. In some aspects, a first spatial order index value may be included in a spatial order field of a first MIB included in a first SSB in the plurality of SSBs. Each SSB in the plurality of simultaneously transmitted SSBs, in some aspects, may include a different MIB from a plurality of MIBs. The first MIB, in some aspects, may be one of the plurality of MIBs and each MIB of the plurality of MIBs may include a different spatial order index value. In some aspects, each SSB in the plurality of simultaneously transmitted SSBs may be associated with a different transmission direction in a plurality of transmission directions, and each transmission direction in the plurality of transmission directions may be identified by a corresponding value of the different spatial order index values. For example, referring to FIGs. 5 and 6, the base station 502/602 may transmit a plurality of simultaneously transmitted SSBs in the SSB burst 608 (e.g., SSB transmissions associated with each of a first beam 511, a second beam 512, a third beam 513, and a fourth beam 514 of the first plurality of SSB transmissions 515, SSB transmissions associated with each of a first beam 521, a second beam 522, a third beam 523, and a fourth beam 524 of the second plurality of SSB transmissions 525, SSB transmissions associated with each of a first beam 531, a second beam 532, a third beam 533, and a fourth beam 534 of the third plurality of SSB transmissions 535, and SSB transmissions associated with one of a first beam 541, a second beam 542, a third beam 543, and a fourth beam 544 of the fourth plurality of SSB transmissions 545).

[0106] At 1006, the base station may simultaneously transmit, via the plurality of transmission directions, RMSI associated with a cell acquisition. For example, 1006 may be performed by CU processor(s) 1212, DU processor(s) 1232, RU processor(s) 1242, transceiver(s) 1246, antenna(s) 1280, and/or time-space beam index component 199 of FIG. 12. The RMSI, in some aspects, may include RMSI transmitted in a direction associated with the first SSB and/or MIB. For example, referring to FIGs. 5 and 6, the base station 502/602 may, transmit the set of RMSI transmissions 612.

[0107] At 1008, the base station may obtain (and/or receive), based on a first spatial order index value in the plurality of spatial order index values included in a first SSB in the plurality of SSBs, at least one RACH message associated with a cell acquisition. In some aspects, obtaining the at least one RACH message at 1008 may include receiving, at 1009, the at least one RACH message via a first RO based on the first spatial order index value and the indication of the number of SSBs in the plurality of (simultaneously transmitted) SSBs. For example, 1008 and 1009 may be performed by CU processor(s) 1212, DU processor(s) 1232, RU processor(s) 1242, transceiver(s) 1246, antenna(s) 1280, and/or time-space beam index component 199 of FIG. 12. The at least one RACH message, in some aspects, may include a preamble in a set of preambles associated with the first spatial order index value and the indication of the number of SSBs in the plurality of simultaneously transmitted SSBs. In some aspects, the set of preambles may be based on the number of SSBs in the plurality of simultaneously transmitted SSBs. For example, referring to FIGs. 5 and 6, the base station 502/602 may receive the RACH message 616, at an RO and including a preamble, based on the SSB time-space configuration 606, a time-space index associated with a SSB transmission received at the UE 604 (e.g., SSBs.o 516 indicating a time index of 0 and a spatial order index of 3), the RMSI associated with cell acquisition via a RMSI transmission received by the UE 604 in a set of RMSI transmissions 612, and the decoding by the UE 604 of the received RMSI transmission and determination of the RACH resources by the UE 604 (e.g., frequency and time resources as well as candidate preambles) at 614.

[0108] FIG. 11 is a diagram 1100 illustrating an example of a hardware implementation for an apparatus 1104. The apparatus 1104 may be a UE, a component of a UE, or may implement UE functionality. In some aspects, the apparatus 1104 may include at least one cellular baseband processor 1124 (also referred to as a modem) coupled to one or more transceivers 1122 (e.g., cellular RF transceiver). The cellular baseband processor(s) 1124 may include at least one on-chip memory 1124'. In some aspects, the apparatus 1104 may further include one or more subscriber identity modules (SIM) cards 1120 and at least one application processor 1106 coupled to a secure digital (SD) card 1108 and a screen 1110. The application processor(s) 1106 may include on-chip memory 1106'. In some aspects, the apparatus 1104 may further include a Bluetooth module 1112, a WLAN module 1114, an SPS module 1116 (e.g., GNSS module), one or more sensor modules 1118 (e.g., barometric pressure sensor / altimeter; motion sensor such as inertial measurement unit (IMU), gyroscope, and/or accelerometer(s); light detection and ranging (LIDAR), radio assisted detection and ranging (RADAR), sound navigation and ranging (SONAR), magnetometer, audio and/or other technologies used for positioning), additional memory modules 1126, a power supply 1130, and/or a camera 1132. The Bluetooth module 1112, the WLAN module 1114, and the SPS module 1116 may include an on-chip transceiver (TRX) (or in some cases, just a receiver (RX)). The Bluetooth module 1112, the WLAN module 1114, and the SPS module 1116 may include their own dedicated antennas and/or utilize one or more antennas 1180 for communication. The cellular baseband processor(s) 1124 communicates through the transceiver(s) 1122 via the one or more antennas 1180 with the UE 104 and/or with an RU associated with a network entity 1102. The cellular baseband processor(s) 1124 and the application processor(s) 1106 may each include a computer-readable medium / memory 1124', 1106', respectively. The additional memory modules 1126 may also be considered a computer- readable medium / memory. Each computer-readable medium / memory 1124', 1106', 1126 may be non-transitory. The cellular baseband processor(s) 1124 and the application processor(s) 1106 are each responsible for general processing, including the execution of software stored on the computer-readable medium / memory. The software, when executed by the cellular baseband processor(s) 1124 / application processor(s) 1106, causes the cellular baseband processor(s) 1124 / application processor(s) 1106 to perform the various functions described supra. The computer-readable medium / memory may also be used for storing data that is manipulated by the cellular baseband processor(s) 1124 / application processor(s) 1106 when executing software. The cellular baseband processor(s) 1124 / application processor(s) 1106 may be a component of the UE 350 and may include the at least one memory 360 and/or at least one of the TX processor 368, the RX processor 356, and the controller/processor 359. In one configuration, the apparatus 1104 may be at least one processor chip (modem and/or application) and include just the cellular baseband processor(s) 1124 and/or the application processor(s) 1106, and in another configuration, the apparatus 1104 may be the entire UE (e.g., see UE 350 of FIG. 3) and include the additional modules of the apparatus 1104.

[0109] As discussed supra, the time-space beam index component 198 may be configured to receive, via a first MIB of a first SSB, a first spatial order index value and obtain, based on the first spatial order index value, RMSI associated with cell acquisition. The timespace beam index component 198 may be within the cellular baseband processor(s) 1124, the application processor(s) 1106, or both the cellular baseband processor(s) 1124 and the application processor(s) 1106. The time-space beam index component 198 may be one or more hardware components specifically configured to carry out the stated processes/algorithm, implemented by one or more processors configured to perform the stated processes/algorithm, stored within a computer-readable medium for implementation by one or more processors, or some combination thereof. When multiple processors are implemented, the multiple processors may perform the stated processes/algorithm individually or in combination. As shown, the apparatus 1104 may include a variety of components configured for various functions. In one configuration, the apparatus 1104, and in particular the cellular baseband processor(s) 1124 and/or the application processor(s) 1106, may include means for receiving, via a first master information block (MIB) of a first synchronization signal block (SSB), a first spatial order index value. The apparatus 1104, and in particular the cellular baseband processor(s) 1124 and/or the application processor(s) 1106, may include means for obtaining, based on the first spatial order index value, remaining minimum system information (RMSI) associated with cell acquisition. The apparatus 1104, and in particular the cellular baseband processor(s) 1124 and/or the application processor(s) 1106, may include means for transmitting, based on the first spatial order index value and the RMSI, at least one random access channel (RACH) message associated with the cell acquisition. The apparatus 1104, and in particular the cellular baseband processor(s) 1124 and/or the application processor(s) 1106, may include means for obtaining an indication of a number of SSBs in the plurality of simultaneously transmitted SSBs. The apparatus 1104, and in particular the cellular baseband processor(s) 1124 and/or the application processor(s) 1106, may include means for transmitting the at least one RACH message via a first random access occasion based on the first spatial order index value and the indication of the number of SSBs in the plurality of simultaneously transmitted SSBs. The apparatus 1104 may further include means for performing any of the aspects described in connection with the flowcharts in FIGs. 7 or 8, and/or performed by the UE 604 in the communication flow of FIG. 6. The means may be the time-space beam index component 198 of the apparatus 1104 configured to perform the functions recited by the means. As described supra, the apparatus 1104 may include the TX processor 368, the RX processor 356, and the controller/processor 359. As such, in one configuration, the means may be the TX processor 368, the RX processor 356, and/or the controller/processor 359 configured to perform the functions recited by the means.

[0110] FIG. 12 is a diagram 1200 illustrating an example of a hardware implementation for a network entity 1202. The network entity 1202 may be a BS, a component of a BS, or may implement BS functionality. The network entity 1202 may include at least one of a CU 1210, a DU 1230, or an RU 1240. For example, depending on the layer functionality handled by the time-space beam index component 199, the network entity 1202 may include the CU 1210; both the CU 1210 and the DU 1230; each of the CU 1210, the DU 1230, and the RU 1240; the DU 1230; both the DU 1230 and the RU 1240; or the RU 1240. The CU 1210 may include at least one CU processor 1212. The CU processor(s) 1212 may include on-chip memory 1212'. In some aspects, the CU 1210 may further include additional memory modules 1214 and a communications interface 1218. The CU 1210 communicates with the DU 1230 through a midhaul link, such as an Fl interface. The DU 1230 may include at least one DU processor 1232. The DU processor(s) 1232 may include on-chip memory 1232'. In some aspects, the DU 1230 may further include additional memory modules 1234 and a communications interface 1238. The DU 1230 communicates with the RU 1240 through a fronthaul link. The RU 1240 may include at least one RU processor 1242. The RU processor(s) 1242 may include on-chip memory 1242'. In some aspects, the RU 1240 may further include additional memory modules 1244, one or more transceivers 1246, one or more antennas 1280, and a communications interface 1248. The RU 1240 communicates with the UE 104. The on-chip memory 1212', 1232', 1242' and the additional memory modules 1214, 1234, 1244 may each be considered a computer-readable medium / memory. Each computer-readable medium / memory may be non-transitory. Each of the processors 1212, 1232, 1242 is responsible for general processing, including the execution of software stored on the computer- readable medium / memory. The software, when executed by the corresponding processor(s) causes the processor(s) to perform the various functions described supra. The computer-readable medium / memory may also be used for storing data that is manipulated by the processor(s) when executing software.

[0111] As discussed supra, the time-space beam index component 199 may be configured to simultaneously transmit a plurality of SSBs, where each SSB in the plurality of SSBs includes a different spatial order index value in a plurality of spatial order index values, and obtain, based on a first spatial order index value in the plurality of spatial order index values included in a first SSB in the plurality of SSBs, at least one RACH message associated with a cell acquisition. The time-space beam index component 199 may be within one or more processors of one or more of the CU 1210, DU 1230, and the RU 1240. The time-space beam index component 199 may be one or more hardware components specifically configured to carry out the stated processes/algorithm, implemented by one or more processors configured to perform the stated processes/algorithm, stored within a computer-readable medium for implementation by one or more processors, or some combination thereof. When multiple processors are implemented, the multiple processors may perform the stated processes/algorithm individually or in combination. The network entity 1202 may include a variety of components configured for various functions. In one configuration, the network entity 1202 may include means for simultaneously transmitting a plurality of synchronization signal blocks (SSBs), where each SSB in the plurality of SSBs includes a different spatial order index value in a plurality of spatial order index values. The network entity 1202 may include means for obtaining, based on a first spatial order index value in the plurality of spatial order index values included in a first SSB in the plurality of SSBs, at least one random access channel (RACH) message associated with a cell acquisition. The network entity 1202 may include means for simultaneously transmitting, via the plurality of transmission directions, remaining minimum system information (RMSI) associated with the cell acquisition, where the at least one RACH message is further based on the RMSI. The network entity 1202 may include means for transmitting an indication of the number of SSBs in the plurality of SSBs. The network entity 1202 may include means for receiving the at least one RACH message via a random access occasion based on the first spatial order index value and the number of SSBs in the plurality of SSBs. The network entity 1202 may further include means for performing any of the aspects described in connection with the flowcharts in FIGs. 9 or 10, and/or performed by the base station in the communication flow of FIG. 6. The means may be the time-space beam index component 199 of the network entity 1202 configured to perform the functions recited by the means. As described supra, the network entity 1202 may include the TX processor 316, the RX processor 370, and the controller/processor 375. As such, in one configuration, the means may be the TX processor 316, the RX processor 370, and/or the controller/processor 375 configured to perform the functions recited by the means or as described in relation to FIGs. 9 and 10.

[0112] Various aspects relate generally to increasing a beam index by using time-space indexing. Some aspects more specifically relate to the use of a larger number of narrower beams in a high frequency band by transmitting multiple spatial beams (e.g., in different directions) in a same time resource and identifying the spatial beams using an enhanced beam index signaled within a MIB. In some examples, a UE may be configured to receive, via a first MIB of a first SSB, a first spatial order index value and obtain, based on the first spatial order index value, RMSI associated with cell acquisition. A network device such as a base station, in some aspects, may be configured to simultaneously transmit a plurality of SSBs, where each SSB in the plurality of SSBs includes a different spatial order index value in a plurality of spatial order index values, and obtain, based on a first spatial order index value in the plurality of spatial order index values included in a first SSB in the plurality of SSBs, at least one RACH message associated with a cell acquisition.

[0113] Particular aspects of the subject matter described in this disclosure can be implemented to realize one or more of the following potential advantages. In some examples, by using time-space indexing, the described techniques can be used to include a higher number of SSB beams per burst, facilitating narrower beams for better cell coverage.

[0114] It is understood that the specific order or hierarchy of blocks in the processes / flowcharts disclosed is an illustration of example approaches. Based upon design preferences, it is understood that the specific order or hierarchy of blocks in the processes / flowcharts may be rearranged. Further, some blocks may be combined or omitted. The accompanying method claims present elements of the various blocks in a sample order, and are not limited to the specific order or hierarchy presented.

[0115] The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects. Thus, the claims are not limited to the aspects described herein, but are to be accorded the full scope consistent with the language claims. Reference to an element in the singular does not mean “one and only one” unless specifically so stated, but rather “one or more.” Terms such as “if,” “when,” and “while” do not imply an immediate temporal relationship or reaction. That is, these phrases, e.g., “when,” do not imply an immediate action in response to or during the occurrence of an action, but simply imply that if a condition is met then an action will occur, but without requiring a specific or immediate time constraint for the action to occur. The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any aspect described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects. Unless specifically stated otherwise, the term “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, B, C, or any combination thereof’ include any combination of A, B, and/or C, and may include multiples of A, multiples of B, or multiples of 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 A only, B only, C only, A and B, A and C, B and C, or A and B and C, where any such combinations may contain one or more member or members of A, B, or C. Sets should be interpreted as a set of elements where the elements number one or more. Accordingly, for a set of X, X would include one or more elements. When at least one processor is configured to perform a set of functions, the at least one processor, individually or in any combination, is configured to perform the set of functions. Accordingly, each processor of the at least one processor may be configured to perform a particular subset of the set of functions, where the subset is the full set, a proper subset of the set, or an empty subset of the set. A processor may be referred to as processor circuitry. A memory / memory module may be referred to as memory circuitry. If a first apparatus receives data from or transmits data to a second apparatus, the data may be received/transmitted directly between the first and second apparatuses, or indirectly between the first and second apparatuses through a set of apparatuses. A device configured to “output” data, such as a transmission, signal, or message, may transmit the data, for example with a transceiver, or may send the data to a device that transmits the data. A device configured to “obtain” data, such as a transmission, signal, or message, may receive, for example with a transceiver, or may obtain the data from a device that receives the data. Information stored in a memory includes instructions and/or data. All structural and functional equivalents to the elements of the various aspects described throughout this 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 encompassed by the claims. Moreover, nothing disclosed herein is dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. The words “module,” “mechanism,” “element,” “device,” and the like may not be a substitute for the word “means.” As such, no claim element is to be construed as a means plus function unless the element is expressly recited using the phrase “means for.” [0116] As used herein, the phrase “based on” shall not be construed as a reference to a closed set of information, one or more conditions, one or more factors, or the like. In other words, the phrase “based on A” (where “A” may be information, a condition, a factor, or the like) shall be construed as “based at least on A” unless specifically recited differently. [0117] The following aspects are illustrative only and may be combined with other aspects or teachings described herein, without limitation.

[0118] Aspect 1 is a method of wireless communication at a user equipment (UE) comprising: receiving, via a first master information block (MIB) of a first synchronization signal block (SSB), a first spatial order index value; and obtaining, based on the first spatial order index value, remaining minimum system information (RMSI) associated with cell acquisition.

[0119] Aspect 2 is the method of aspect 1, wherein the first spatial order index value is included in a spatial order field of the first MIB.

[0120] Aspect 3 is the method of any of aspects 1 and 2, wherein the first SSB is one of a plurality of simultaneously transmitted SSBs, wherein each SSB in the plurality of simultaneously transmitted SSBs includes a different MIB from a plurality of MIBs, and wherein the first MIB is one of the plurality of MIBs and each MIB of the plurality of MIBs includes a different spatial order index value.

[0121] Aspect 4 is the method of aspect 3, wherein each SSB in the plurality of simultaneously transmitted SSBs is associated with a different transmission direction in a plurality of transmission directions, and wherein each transmission direction in the plurality of transmission directions is identified by a corresponding value of the different spatial order index values.

[0122] Aspect 5 is the method of any of aspects 3 and 4, further comprising: transmitting, based on the first spatial order index value and the RMSI, at least one random access channel (RACH) message associated with the cell acquisition.

[0123] Aspect 6 is the method of aspect 5, further comprising: obtaining an indication of a number of SSBs in the plurality of simultaneously transmitted SSBs.

[0124] Aspect 7 is the method of aspect 6, wherein the at least one RACH message comprises a preamble in a set of preambles associated with the first spatial order index value and the indication of the number of SSBs in the plurality of simultaneously transmitted SSBs.

[0125] Aspect 8 is the method of aspect 7, wherein the set of preambles is based on the number of SSBs in the plurality of simultaneously transmitted SSBs.

[0126] Aspect 9 is the method of any of aspects 6 to 8, wherein transmitting the at least one RACH message comprises transmitting the at least one RACH message via a first random access occasion based on the first spatial order index value and the indication of the number of SSBs in the plurality of simultaneously transmitted SSBs.

[0127] Aspect 10 is a method of wireless communication at a network device comprising: simultaneously transmitting a plurality of synchronization signal blocks (SSBs), wherein each SSB in the plurality of SSBs includes a different spatial order index value in a plurality of spatial order index values; and obtaining, based on a first spatial order index value in the plurality of spatial order index values included in a first SSB in the plurality of SSBs, at least one random access channel (RACH) message associated with a cell acquisition.

[0128] Aspect 11 is the method of aspect 10, wherein a first spatial order index value is included in a spatial order field of a first MIB in the first SSB.

[0129] Aspect 12 is the method of any of aspects 10 and 11, wherein each SSB in the plurality of SSBs is associated with a different transmission direction in a plurality of transmission directions, and wherein each transmission direction in the plurality of transmission directions is identified by a corresponding value in the plurality of spatial order index values. [0130] Aspect 13 is the method of aspect 12, further comprising: simultaneously transmitting, via the plurality of transmission directions, remaining minimum system information (RMSI) associated with the cell acquisition, wherein the at least one RACH message is further based on the RMSI.

[0131] Aspect 14 is the method of aspect 13, wherein the at least one RACH message comprises a preamble in a set of preambles associated with the first spatial order index value and a number of SSBs in the plurality of SSBs.

[0132] Aspect 15 is the method of aspect 14, further comprising: transmitting an indication of the number of SSBs in the plurality of SSBs.

[0133] Aspect 16 is the method of any of aspects 14 and 15, wherein receiving the at least one RACH message comprises receiving the at least one RACH message via a random access occasion based on the first spatial order index value and the number of SSBs in the plurality of SSBs.

[0134] Aspect 17 is an apparatus for wireless communication at a device including a memory and at least one processor coupled to the memory and, based at least in part on information stored in the memory, the at least one processor is configured to implement any of aspects 1 to 9.

[0135] Aspect 18 is the apparatus of aspect 17, further including a transceiver or an antenna coupled to the at least one processor.

[0136] Aspect 19 is an apparatus for wireless communication at a device including means for implementing any of aspects 1 to 9.

[0137] Aspect 20 is a computer-readable medium (e.g., a non-transitory computer-readable medium) storing computer executable code, where the code when executed by a processor causes the processor to implement any of aspects 1 to 9.

[0138] Aspect 21 is an apparatus for wireless communication at a device including a memory and at least one processor coupled to the memory and, based at least in part on information stored in the memory, the at least one processor is configured to implement any of aspects 10 to 16.

[0139] Aspect 22 is the apparatus of aspect 21, further including a transceiver or an antenna coupled to the at least one processor. [0140] Aspect 23 is an apparatus for wireless communication at a device including means for implementing any of aspects 10 to 16.

[0141] Aspect 24 is a computer-readable medium (e.g., a non-transitory computer-readable medium) storing computer executable code, where the code when executed by a processor causes the processor to implement any of aspects 10 to 16.

Claims

CLAIMS WHAT IS CLAIMED IS:

1. An apparatus for wireless communication at a user equipment (UE), comprising: at least one memory; and at least one processor coupled to the at least one memory and, based at least in part on stored information that is stored in the at least one memory, the at least one processor, individually or in any combination, is configured to: receive, via a first master information block (MIB) of a first synchronization signal block (SSB), a first spatial order index value; and obtain, based on the first spatial order index value, remaining minimum system information (RMSI) associated with cell acquisition.

2. The apparatus of claim 1, wherein the first spatial order index value is included in a spatial order field of the first MIB.

3. The apparatus of claim 1, wherein the first SSB is one of a plurality of simultaneously transmitted SSBs, wherein each SSB in the plurality of simultaneously transmitted SSBs includes a different MIB from a plurality of MIBs, and wherein the first MIB is one of the plurality of MIBs and each MIB of the plurality of MIBs includes a different spatial order index value.

4. The apparatus of claim 3, wherein each SSB in the plurality of simultaneously transmitted SSBs is associated with a different transmission direction in a plurality of transmission directions, and wherein each transmission direction in the plurality of transmission directions is identified by a corresponding value of the different spatial order index values.

5. The apparatus of claim 3, further comprising a transceiver coupled to the at least one processor, wherein the at least one processor, individually or in any combination, is further configured to: transmit, via the transceiver and based on the first spatial order index value and the RMSI, at least one random access channel (RACH) message associated with the cell acquisition.

6. The apparatus of claim 5, wherein the at least one processor, individually or in any combination, is further configured to: obtain an indication of a number of SSBs in the plurality of simultaneously transmitted SSBs.

7. The apparatus of claim 6, wherein the at least one RACH message comprises a preamble in a set of preambles associated with the first spatial order index value and the indication of the number of SSBs in the plurality of simultaneously transmitted SSBs.

8. The apparatus of claim 7, wherein the set of preambles is based on the number of SSBs in the plurality of simultaneously transmitted SSBs.

9. The apparatus of claim 6, wherein, to transmit the at least one RACH message, the at least one processor, individually or in any combination, is configured to transmit the at least one RACH message via a first random access occasion based on the first spatial order index value and the indication of the number of SSBs in the plurality of simultaneously transmitted SSBs.

10. An apparatus for wireless communication at a network device, comprising: at least one memory; and at least one processor coupled to the at least one memory and, based at least in part on stored information that is stored in the at least one memory, the at least one processor, individually or in any combination, is configured to: simultaneously transmit a plurality of synchronization signal blocks (SSBs), wherein each SSB in the plurality of SSBs includes a different spatial order index value in a plurality of spatial order index values; and obtain, based on a first spatial order index value in the plurality of spatial order index values included in a first SSB in the plurality of SSBs, at least one random access channel (RACH) message associated with a cell acquisition.

11. The apparatus of claim 10, wherein the first spatial order index value is included in a spatial order field of a first MIB in the first SSB.

12. The apparatus of claim 10, wherein each SSB in the plurality of SSBs is associated with a different transmission direction in a plurality of transmission directions, and wherein each transmission direction in the plurality of transmission directions is identified by a corresponding value in the plurality of spatial order index values.

13. The apparatus of claim 12, further comprising a transceiver coupled to the at least one processor, wherein the at least one processor, individually or in any combination, is further configured to: simultaneously transmit, via the transceiver and via the plurality of transmission directions, remaining minimum system information (RMSI) associated with the cell acquisition, wherein the at least one RACH message is further based on the RMSI.

14. The apparatus of claim 13, wherein the at least one RACH message comprises a preamble in a set of preambles associated with the first spatial order index value and a number of SSBs in the plurality of SSBs.

15. The apparatus of claim 14, wherein the at least one processor, individually or in any combination, is further configured to: transmit an indication of the number of SSBs in the plurality of SSBs.

16. The apparatus of claim 14, wherein, to receive the at least one RACH message, the at least one processor, individually or in any combination, is configured to receive the at least one RACH message via a random access occasion based on the first spatial order index value and the number of SSBs in the plurality of SSBs.

17. A method of wireless communication at a user equipment (UE) comprising: receiving, via a first master information block (MIB) of a first synchronization signal block (SSB), a first spatial order index value; and obtaining, based on the first spatial order index value, remaining minimum system information (RMSI) associated with cell acquisition.

18. The method of claim 17, wherein the first spatial order index value is included in a spatial order field of the first MIB.

19. The method of claim 17, further comprising: transmitting, based on the first spatial order index value and the RMSI, at least one random access channel (RACH) message associated with the cell acquisition.

20. The method of claim 19, further comprising: obtaining an indication of a number of SSBs in a plurality of simultaneously transmitted SSBs including the first SSB.

21. The method of claim 20, wherein the at least one RACH message comprises a preamble in a set of preambles associated with the first spatial order index value and the indication of the number of SSBs in the plurality of simultaneously transmitted SSBs.

22. The method of claim 21, wherein the set of preambles is based on the number of SSBs in the plurality of simultaneously transmitted SSBs.

23. The method of claim 20, wherein transmitting the at least one RACH message comprises transmitting the at least one RACH message via a first random access occasion based on the first spatial order index value and the indication of the number of SSBs in the plurality of simultaneously transmitted SSBs.

24. A method of wireless communication at a network device comprising: simultaneously transmitting a plurality of synchronization signal blocks (SSBs), wherein each SSB in the plurality of SSBs includes a different spatial order index value in a plurality of spatial order index values; and obtaining, based on a first spatial order index value in the plurality of spatial order index values included in a first SSB in the plurality of SSBs, at least one random access channel (RACH) message associated with a cell acquisition.

25. The method of claim 24, wherein the first spatial order index value is included in a spatial order field of a first MIB in the first SSB.

26. The method of claim 24, wherein each SSB in the plurality of SSBs is associated with a different transmission direction in a plurality of transmission directions, and wherein each transmission direction in the plurality of transmission directions is identified by a corresponding value in the plurality of spatial order index values.

27. The method of claim 26, further comprising: simultaneously transmitting, via the plurality of transmission directions, remaining minimum system information (RMSI) associated with the cell acquisition, wherein the at least one RACH message is further based on the RMSI.

28. The method of claim 27, wherein the at least one RACH message comprises a preamble in a set of preambles associated with the first spatial order index value and a number of SSBs in the plurality of SSBs.

29. The method of claim 28, further comprising: transmitting an indication of the number of SSBs in the plurality of SSBs.

30. The method of claim 28, wherein receiving the at least one RACH message comprises receiving the at least one RACH message via a random access occasion based on the first spatial order index value and the number of SSBs in the plurality of SSBs.