Details of 8-port SRS mapping to multiple OFDM symbols

Abstract

A method and related apparatus for wireless communication at a user equipment (UE) are provided. In the method, the UE sequentially maps a first number of sounding reference signal (SRS) ports to a second number of orthogonal frequency division multiplexing (OFDM) symbols. The first number and the second number are greater than one. The UE further transmits SRS from the first number of SRS ports on the second number of OFDM symbols based on the mapping.

Description

[0001] Cross - Reference to Related Applications

[0002] This application claims the benefit and priority of U.S. Provisional Application Serial No. 63 / 478,480, filed on January 4, 2023, entitled "DETAILS FOR 8PORTS SRS MAPPING TO MULTIPLE OFDM SYMBOLS", and U.S. Non - Provisional Patent Application Serial No. 18 / 520,038, filed on November 27, 2023, entitled "DETAILS FOR 8PORTS SRS MAPPING TO MULTIPLE OFDM SYMBOLS", the entire disclosures of which are hereby incorporated by reference in their entirety. Technical Field

[0003] This disclosure generally relates to communication systems, and more particularly to wireless communication with eight - port sounding reference signal (SRS) mapping to multiple orthogonal frequency division multiplexing (OFDM) symbols. Background Art

[0004] Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasting. A typical wireless communication system 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.

[0005] These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate at the city, national, regional, and even global levels. An example telecommunication standard is 5G New Radio (NR). 5G NR is part of the ongoing evolution of mobile broadband promulgated by the Third Generation Partnership Project (3GPP) to meet new requirements associated with latency, reliability, security, scalability (e.g., with the Internet of Things (IoT)), and other requirements. 5G NR includes services associated with enhanced mobile broadband (eMBB), massive machine - type communication (mMTC), and ultra - reliable low - latency communication (URLLC). Certain aspects of 5G NR may be based on the 4G Long Term Evolution (LTE) standard. Further improvements to 5G NR technology are needed. In addition, these improvements may also be applicable to other multiple access technologies and telecommunication standards that employ these technologies. Summary of the Invention

[0006] A simplified summary of one or more aspects is presented below in order to provide a basic understanding of such aspects. This Summary of the Invention is not an extensive overview of all contemplated aspects. The Summary of the Invention neither identifies key or critical elements of all aspects nor describes 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.

[0007] In one aspect of the present disclosure, there are provided methods, computer-readable media, and apparatuses for wireless communication at a user equipment (UE). The apparatus may include a memory and at least one processor coupled to the memory. At least partially based on information stored in the memory, the at least one processor may be configured to sequentially map a first number of sounding reference signal (SRS) ports to a second number of orthogonal frequency division multiplexing (OFDM) symbols, where the first number and the second number are each greater than one; and transmit SRS from the first number of SRS ports on the second number of OFDM symbols based on the mapping.

[0008] In one aspect of the present disclosure, there are provided methods, computer-readable media, and apparatuses for wireless communication at a network entity. The apparatus may include a memory and at least one processor coupled to the memory. At least partially based on information stored in the memory, the at least one processor may be configured to receive SRS from a first number of SRS ports of a UE that are sequentially mapped on a second number of OFDM symbols, where the second number is greater than one; and receive a physical uplink shared channel (PUSCH) transmission based on the SRS.

[0009] To achieve the foregoing and related purposes, one or more aspects may include the features described in detail below and particularly pointed out in the claims. The following description and the drawings set forth in detail some illustrative features of one or more aspects. However, these features are indicative of only some of the various ways in which the principles of the various aspects may be employed. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is a diagram illustrating an example of a wireless communication system and an access network.

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

[0012] Figure 2B is a diagram illustrating an example of a downlink (DL) channel within a subframe in accordance with various aspects of the present disclosure.

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

[0014] Figure 2D A diagram illustrating an example of an uplink (UL) channel within a subframe according to various aspects of the present disclosure.

[0015] Figure 3 A diagram illustrating an example of a base station and a user equipment (UE) in an access network.

[0016] Figure 4 A diagram illustrating an example UE communicating with a network entity according to various aspects of the present disclosure.

[0017] Figure 5A and Figure 5B A diagram illustrating an example sounding reference signal (SRS) port mapping to multiple orthogonal frequency division multiplexing (OFDM) symbols according to various aspects of the present disclosure.

[0018] Figure 6A and Figure 6B A diagram illustrating an example SRS port mapping to multiple OFDM symbols according to various aspects of the present disclosure.

[0019] Figure 7A and Figure 7B A diagram illustrating an example SRS repetition according to various aspects of the present disclosure.

[0020] Figure 8A and Figure 8B A diagram illustrating the association between physical uplink shared channel (PUSCH) transmission and SRS resources.

[0021] Figure 9A and Figure 9B A diagram illustrating the association between PUSCH transmission and SRS resources in partial SRS resource discard according to various aspects of the present disclosure.

[0022] Figure 10A and Figure 10B A diagram illustrating the association between PUSCH transmission and SRS resources in partial SRS resource discard according to various aspects of the present disclosure.

[0023] Figure 11 A call flow diagram illustrating a method of wireless communication according to various aspects of the present disclosure.

[0024] Figure 12 A flowchart illustrating a method of wireless communication at a UE according to various aspects of the present disclosure.

[0025] Figure 13 A flowchart illustrating a method of wireless communication at a UE according to various aspects of the present disclosure.

[0026] Figure 14 is a flowchart illustrating a method for wireless communication at a network entity in accordance with various aspects of the present disclosure.

[0027] Figure 15 is a flowchart illustrating a method for wireless communication at a network entity in accordance with various aspects of the present disclosure.

[0028] Figure 16 is a diagram illustrating an example of a hardware implementation for an example apparatus and / or network entity.

[0029] Figure 17 is a diagram illustrating an example of a hardware implementation for an example network entity. Detailed Description

[0030] In wireless communication, the ability to effectively manage signal transmission and reception across multiple antennas is important for maintaining data throughput and signal reliability in various environments. The example aspects presented herein provide various mapping schemes for mapping different sounding reference signal (SRS) ports to different orthogonal frequency division multiplexing (OFDM) symbols. The proposed mapping schemes enable up to eight uplink (UL) transmissions (8Tx) in a multiple-input multiple-output (MIMO) environment to support four and more layers (e.g., data streams) per user equipment (UE) in the UL for a variety of applications including customer premise equipment (CPE), fixed wireless access (FWA), vehicles, and industrial equipment.

[0031] Various aspects generally relate to wireless communication and more specifically to eight-port SRS mapping across multiple OFDM symbols. Some aspects more specifically relate to a UE sequentially mapping a first number of SRS ports to a second number of OFDM symbols, the first number and the second number each being greater than one; and transmitting SRS from the first number of SRS ports on the second number of OFDM symbols based on the mapping. In some examples, the first number of SRS ports may be mapped to consecutive or non-consecutive symbols based on one or more of SRS usage, codebook, or coherence. In some examples, the first number of SRS ports may be mapped to symbols in the same time slot, the same sub-time slot, different time slots, or different sub-time slots based on one or more of SRS usage, codebook, or coherence. In some examples, in response to discarding at least one SRS port among the first number of SRS ports communicating with a network entity, the association of the physical uplink shared channel (PUSCH) with the SRS port may be based on one or more of SRS usage, codebook, or coherence.

[0032] Certain 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 sequentially mapping a first number of SRS ports to a second number of OFDM symbols, where each of the first number and the second number is greater than one, the techniques described can be used to implement or enhance 8Tx UL operations to support four or more layers per UE in UL transmissions. Thus, the aspects presented herein improve the efficiency of wireless communications. In some examples, by considering different scenarios when mapping SRS ports to OFDM symbols, such as continuous or discontinuous symbol mapping, slot or sub-slot boundaries, and different coherence levels of the codebook or precoder, the techniques described provide greater operational flexibility, especially in dynamic network environments. In some examples, by considering SRS repetition and potential SRS discard scenarios, the techniques described ensure the continuity and reliability of communications even when partial signal loss occurs. Thus, the techniques described enhance the capabilities and reliability of MIMO systems in wireless communications.

[0033] The detailed description set forth below in connection with the accompanying drawings is a description of various configurations and does not represent the only configurations in which the concepts described herein can be practiced. For a thorough understanding of the various concepts, the detailed description includes specific details. However, the concepts can be practiced without these specific details. In some instances, well-known structures and components are shown in block diagram form to avoid obscuring such concepts.

[0034] Certain aspects of a telecommunications system are presented with reference to various devices and methods. These devices and methods are described in the following detailed description and illustrated in the drawings by various blocks, components, circuits, processes, algorithms, etc. (collectively referred to as "elements"). These elements can be implemented using electronic hardware, computer software, or any combination thereof. Whether these elements are implemented as hardware or software depends on the particular application and the design constraints imposed on the overall system.

[0035] As an example, an element, or any portion of an element, or any combination of elements can be implemented as a "processing system" that includes one or more processors. When multiple processors are implemented, the multiple processors can perform 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, system 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 functions described throughout this disclosure. One or more processors in the processing system can execute software. Software should be broadly construed 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, regardless of whether it is called software, firmware, middleware, microcode, hardware description language, or other terms.

[0036] Thus, in one or more example aspects, embodiments, and / or use cases, the described functions can be implemented in hardware, software, or any combination thereof. If implemented in software, the functions can be stored or encoded on a computer-readable medium as one or more instructions or code. Computer-readable media includes computer storage media. Storage media can be any available media that can be accessed by a computer. By way of example, such computer-readable media can include random access memory (RAM), read only memory (ROM), electrically erasable programmable ROM (EEPROM), optical disk storage, magnetic disk storage, other magnetic storage devices, combinations of these types of computer-readable media, or any other media that can be used to store computer-executable code in the form of instructions or data structures that can be accessed by a computer.

[0037] While aspects, embodiments, and / or use cases are described by way of some examples in this application, additional or different aspects, embodiments, and / or use cases may arise in many different arrangements and scenarios. The aspects, embodiments, and / or use cases described herein may be implemented across many different platform types, devices, systems, shapes, sizes, and packaging arrangements. For example, the aspects, embodiments, and / or use cases may be embodied via integrated chips and other non-module-component-based devices (e.g., end-user devices, vehicles, communication devices, computing devices, industrial equipment, retail / purchase devices, medical devices, artificial intelligence (AI)-enabled devices, etc.). Although some examples may or may not be specifically targeted at a use case or application, the examples described may have broad applicability. The aspects, embodiments, and / or use cases may range from chip-level or modular components to non-modular, non-chip-level embodiments, and further to aggregated, distributed, or original equipment manufacturer (OEM) devices or systems incorporating one or more of the technologies herein. In some practical settings, devices incorporating the aspects and features described may also include additional components and features for implementing and practicing the claimed and described aspects. For example, the transmission and reception of wireless signals necessarily includes multiple components for analog and digital purposes (e.g., hardware components including antennas, RF chains, power amplifiers, modulators, buffers, processors, interleavers, adders / summers, etc.). The technologies described herein may be practiced in a wide variety of devices, chip-level components, systems, distributed arrangements, aggregated components, or disaggregated components, end-user devices, etc., of various sizes, shapes, and configurations.

[0038] The deployment of a communication system (such as a 5G NR system) can be arranged with various components or constituent parts in a variety of ways. In a 5G NR system or network, network nodes, network entities, mobility elements of the network, radio access network (RAN) nodes, core network nodes, network elements, or network equipment (such as a base station (BS)) or one or more units (or one or more components) performing base station functions 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), transmit receive point (TRP), or cell, etc.) may be implemented as an aggregated base station (also referred to as a stand-alone BS or monolithic BS) or a disaggregated base station.

[0039] A centralized base station may be configured to utilize a radio protocol stack that is physically or logically integrated within a single RAN node. A split base station may be configured to utilize a protocol stack that is physically or logically distributed across 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 across one or more other RAN nodes. A DU may be implemented to communicate with one or more RUs. Each of the CU, DU, and RU may be implemented as a virtual unit, i.e., a virtual central unit (VCU), a virtual distributed unit (VDU), or a virtual radio unit (VRU).

[0040] Base station operation or network design may consider the aggregation characteristics of base station functions. For example, a split base station may be used in an integrated access backhaul (IAB) network, an open radio access network (O-RAN, such as a network configuration initiated by the O-RAN Alliance), or a virtualized radio access network (vRAN, also known as a cloud radio access network (C-RAN)). Splitting may include distributing functions across two or more units at various physical locations, as well as virtually distributing the functions of at least one unit, which may enable flexibility in network design. The various units of a split base station or split RAN architecture may be configured for wired or wireless communication with at least one other unit.

[0041] Figure 1 FIG. 100 is a diagram illustrating an example of a wireless communication system and an access network. The illustrated wireless communication system includes a split base station architecture. The split base station architecture may include one or more CUs 110, which may communicate directly with the core network 120 via a backhaul link, or indirectly with the core network 120 through one or more split 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. The CU 110 may communicate with one or more DUs 130 via a respective midhaul link, such as an F1 interface. The DU 130 may communicate with one or more RUs 140 via a respective fronthaul link. The RU 140 may communicate with a respective UE 104 via one or more radio frequency (RF) access links. In some embodiments, the UE 104 may be served simultaneously by multiple RUs 140.

[0042] Each of the units (i.e., CU 110, DU 130, RU 140, and near-RT RIC 125, non-RT RIC 115, and SMO framework 105) may include or be coupled to one or more interfaces configured to receive or transmit signals, data, or information (collectively, signals) via a wired or wireless transmission medium. Each of the units, or an associated processor or controller that provides instructions to the communication interfaces of these units, may be configured to communicate with one or more of the other units via the transmission medium. For example, these units may include a wired interface configured to receive signals or transmit signals to one or more of the other units via the wired transmission medium. Additionally, these units may include a wireless interface that may include a receiver, transmitter, or transceiver (such as an RF transceiver) configured to receive or transmit signals, or both, to one or more of the other units via the wireless transmission medium.

[0043] In some aspects, the CU 110 may host one or more higher layer control functions. Such control functions may include radio resource control (RRC), packet data convergence protocol (PDCP), service data adaptation protocol (SDAP), etc. Each control function may be implemented using an interface that is configured to communicate signals with other control functions hosted by the CU 110. The CU 110 may be configured to handle user plane functions (i.e., central unit-user plane (CU-UP)), control plane functions (i.e., central unit-control plane (CU-CP)), or a combination thereof. In some specific implementations, the CU 110 may be logically split into one or more CU-UP units and one or more CU-CP units. When implemented in an O-RAN configuration, the CU-UP unit may communicate bidirectionally with the CU-CP unit via an interface (such as an E1 interface). As needed, the CU 110 may be implemented to communicate with the DU 130 for network control and signaling.

[0044] The DU 130 may correspond to a logical unit that includes one or more base station functions for controlling 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 higher physical (PHY) layers (such as modules for forward error correction (FEC) encoding and decoding, scrambling, modulation and demodulation, etc.) based 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 lower PHY layers. Each layer (or module) may be implemented using an interface configured to communicate signals with other layers (and modules) hosted by the DU 130 or with control functions hosted by the CU 110.

[0045] The lower layer functions can be implemented by one or more RUs 140. In some deployments, the RUs 140 controlled by the DU 130 can correspond to logical nodes that host 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, etc.) or both, at least partially based on function splitting (such as lower layer function splitting). In such an architecture, the RU 140 can be implemented to handle over-the-air (OTA) communication with one or more UEs 104. In some embodiments, the real-time and non-real-time aspects of the control plane communication and user plane communication with the RU 140 can be controlled by the corresponding DU 130. In some scenarios, this configuration enables the implementation of the DU 130 and CU 110 in a cloud-based RAN architecture (such as a vRAN architecture).

[0046] The SMO framework 105 can be configured to support the deployment and orchestration of RANs for both non-virtualized network elements and virtualized network elements. For non-virtualized network elements, the SMO framework 105 can be configured to support the deployment of dedicated physical resources for RAN coverage requirements, which can be managed via an operation and maintenance interface (such as the O1 interface). For virtualized network elements, the SMO framework 105 can be configured to interact with a cloud computing platform (such as the Open Cloud (O-Cloud) 190) to perform network element lifecycle management (such as instantiating virtualized network elements) via a cloud computing platform interface (such as the O2 interface). Such virtualized network elements can include, but are not limited to, the CU 110, DU 130, RU 140, and near RT RIC 125. In some embodiments, the SMO framework 105 can communicate with the hardware aspects of the 4G RAN (such as the Open eNB (O-eNB) 111) via the O1 interface. Additionally, in some embodiments, the SMO framework 105 can communicate directly with one or more RUs 140 via the O1 interface. The SMO framework 105 can also include a non-RT RIC 115 configured to support the functions of the SMO framework 105.

[0047] The non-RT RIC 115 can be configured to include logic functions that enable non-real-time control and optimization of RAN elements and resources, artificial intelligence (AI) / machine learning (ML) (AI / ML) workflows including model training and updating, or policy-based guidance of applications / features in the near-RT RIC 125. The non-RT RIC 115 can be coupled to or communicate with the near-RT RIC 125 (such as via the A1 interface). The near-RT RIC 125 can be configured to include logic functions that enable near-real-time control and optimization of RAN elements and resources via data collection and actions through an interface (such as via the E2 interface) that connects one or more CUs 110, one or more DUs 130, or both, and an O-eNB to the near-RT RIC 125.

[0048] In some embodiments, to generate an AI / ML model to be deployed in the near-RT RIC 125, the non-RT RIC 115 can receive parameters or external enrichment information from an external server. Such information can be utilized by the near-RT RIC 125 and can be received from non-network data sources or from network functions at the SMO framework 105 or the non-RT RIC 115. In some examples, the non-RT RIC 115 or the near-RT RIC 125 can be configured to tune RAN behavior or performance. For example, the non-RT RIC 115 can monitor long-term trends and patterns of performance and employ an AI / ML model to perform corrective actions through the SMO framework 105 (such as via reconfiguration of O1) or via creation of RAN management policies (such as A1 policies).

[0049] At least one of CU 110, DU 130, and RU 140 may be referred to as base station 102. Thus, base station 102 may include one or more of CU 110, DU 130, and RU 140 (each component is indicated by a dashed line to indicate that each component may or may not be included in base station 102). Base station 102 provides an access point for UE 104 to core network 120. Base station 102 may include macro cells (high-power cellular base stations) and / or small cells (low-power cellular base stations). Small cells include femtocells, picocells, and microcells. A network that includes both small cells and macro cells may be referred to as a heterogeneous network. The heterogeneous network may also include a home evolved Node B (eNB) (HeNB) that may provide services to a restricted group referred to as a closed subscriber group (CSG). The communication link between RU 140 and UE 104 may include an uplink (UL) (also referred to as a reverse link) transmission from UE 104 to RU 140 and / or a downlink (DL) (also referred to as a forward link) transmission from RU 140 to UE 104. The communication link may use multiple-input multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, and / or transmit diversity. The communication link may pass through one or more carriers. For each carrier allocated in carrier aggregation with a total of up to Yx MHz (x component carriers) for transmission in each direction, base station 102 / UE 104 may use a spectrum with a bandwidth of up to Y MHz (e.g., 5 MHz, 10 MHz, 15 MHz, 20 MHz, 100 MHz, 400 MHz, etc.). These carriers may or may not be adjacent to each other. The allocation of carriers may be asymmetric with respect to DL and UL (e.g., more or fewer carriers may be allocated for DL compared to UL). Component carriers may include a primary component carrier and one or more secondary component carriers. The primary component carrier may be referred to as a primary cell (PCell) and the secondary component carriers may be referred to as secondary cells (SCells).

[0050] Some UEs 104 may use device-to-device (D2D) communication links 158 to communicate with each other. D2D communication links 158 may use DL / UL wireless wide area network (WWAN) spectrum. D2D communication links 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 carried out through various wireless D2D communication systems, such as, for example, Bluetooth TM (Bluetooth is a trademark of the Bluetooth Special Interest Group (SIG)), Wi-Fi based on the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard TM (Wi-Fi is a trademark of the Wi-Fi Alliance), LTE, or NR.

[0051] The wireless communication system may further include a Wi-Fi AP 150 that communicates with the UE 104 (also referred to as a Wi-Fi station (STA)) via a communication link 154, for example, in an unlicensed spectrum such as the 5 GHz unlicensed spectrum. When communicating in an unlicensed spectrum, the UE 104 / AP 150 may perform a Clear Channel Assessment (CCA) before communication to determine whether the channel is available.

[0052] The electromagnetic spectrum is generally subdivided into various categories, frequency bands, channels, etc. based on frequency / wavelength. In 5G NR, two initial operating frequency bands have been identified as Frequency Range Designation FR1 (410 MHz - 7.125 GHz) and FR2 (24.25 GHz - 52.6 GHz). Although a part of FR1 is greater than 6 GHz, in various documents and articles, FR1 is generally referred to (interchangeably) as the "sub-6 GHz" band. Regarding FR2, a similar naming issue sometimes occurs, which is generally (interchangeably) referred to as the "millimeter wave" band in documents and articles, although it is different from the Extremely High Frequency (EHF) band (30 GHz - 300 GHz) identified as the "millimeter wave" band by the International Telecommunication Union (ITU).

[0053] The frequencies between FR1 and FR2 are generally referred to as mid-band frequencies. Recent 5G NR research has identified operating frequency bands for these mid-band frequencies as Frequency Range Designation FR3 (7.125 GHz - 24.25 GHz). The bands falling within FR3 may inherit FR1 characteristics and / or FR2 characteristics, and thus can effectively extend the features of FR1 and / or FR_{2} to 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 frequency bands have been identified as Frequency Range Designation 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.

[0054] Considering the above aspects, unless otherwise specifically stated, if terms such as "sub-6 GHz" are used in this document, they can broadly represent frequencies that can be less than 6 GHz, can be within FR1, or can include mid-band frequencies. In addition, unless otherwise specifically stated, if terms such as "millimeter wave" are used in this document, they can broadly represent frequencies that can include mid-band frequencies, can be within FR2, FR4, FR2-2, and / or FR5, or can be within the EHF band.

[0055] Base station 102 and UE 104 may each include multiple antennas (such as antenna elements, antenna panels, and / or antenna arrays) to facilitate beamforming. Base station 102 may transmit beamformed signal 182 to UE 104 in one or more transmission directions. UE 104 may receive the beamformed signal from base station 102 in one or more reception directions. UE 104 may also transmit beamformed signal 184 to base station 102 in one or more transmission directions. Base station 102 may receive the beamformed signal from UE 104 in one or more reception directions. Base station 102 / UE 104 may perform beam training to determine the optimal reception and transmission directions for each of base station 102 / UE 104. The transmission and reception directions of base station 102 may be the same or may not be the same. The transmission and reception directions of UE 104 may be the same or may not be the same.

[0056] Base station 102 may include and / or be referred to as gNB, Node B, eNB, access point, base station transceiver, radio base station, radio transceiver, transceiver function, basic service set (BSS), extended service set (ESS), TRP, network node, network entity, network equipment, or some other suitable term. Base station 102 may be implemented as an integrated access and backhaul (IAB) node, relay node, sidelink node, a centralized (monolithic) base station with a baseband unit (BBU) (including CU and DU) and RU, or as a distributed base station including one or more of CU, DU, and / or RU. A set of base stations including distributed base stations and / or centralized base stations may be referred to as a next generation (NG) RAN (NG-RAN).

[0057] 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 a control node that processes signaling between the UE 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 identity handling, access authorization, and subscription management. 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, in general, one or more Location Servers 168 may include one or more location / locationing servers, which may include one or more of the GMLC 165, LMF 166, a Position Determination Entity (PDE), a Serving Mobile Location Center (SMLC), a Mobile Positioning Center (MPC), etc. The GMLC 165 and LMF 166 support UE location services. The GMLC 165 provides an interface for clients / applications (e.g., emergency services) to access UE location information. The LMF 166 receives measurement and assistance information from the NG-RAN and the UE 104 via the AMF 161 to calculate the location of the UE 104. The NG-RAN may utilize one or more positioning methods to determine the location of the UE 104. Positioning the UE 104 may involve signal measurements, location estimation, and an optional speed calculation based on these measurements. The signal measurements may be performed by the UE 104 and / or the base station 102 serving the UE 104. The measured signals may be based on a Satellite Positioning System (SPS) 170 (e.g., a Global Navigation Satellite System (GNSS), Global Positioning System (GPS), Non-Terrestrial Network (NTN), or one or more of other satellite positioning / locationing systems), LTE signals, Wireless Local Area Network (WLAN) signals, Bluetooth signals, a Terrestrial Beacon System (TBS), sensor-based information (e.g., an atmospheric pressure sensor, a motion sensor), an NR Enhanced Cell ID (NR E-CID) method, 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 one or more of other systems / signals / sensors).

[0058] Examples of the UE 104 include cellular phones, smart phones, Session Initiation Protocol (SIP) phones, laptop computers, personal digital assistants (PDAs), satellite radios, global positioning systems, multimedia devices, video devices, digital audio players (e.g., MP3 players), cameras, game consoles, tablet computers, smart devices, wearable devices, vehicles, electricity meters, air pumps, large or small kitchen appliances, healthcare devices, implants, sensors / actuators, displays, or any other device with similar functionality. Some of the UEs in the UE 104 may be referred to as IoT devices (e.g., parking meters, air pumps, toasters, vehicles, heart monitors, etc.). The UE 104 may also be referred to as a station, mobile station, subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, remote terminal, cell phone, user agent, mobile client, client, or some other suitable term. In some scenarios, the term UE may also apply to one or more companion devices, such as in a device cluster arrangement. One or more of these devices may access the network jointly and / or access the network individually.

[0059] Referring again to Figure 1 , in certain aspects, the UE 104 may include an SRS mapping component 198. The SRS mapping component 198 may be configured to sequentially map a first number of SRS ports to a second number of OFDM symbols. The first number and the second number may each be greater than one. The SRS mapping component 198 may be further configured to transmit SRS from the first number of SRS ports on the second number of OFDM symbols based on the mapping. In certain aspects, the base station 102 may include an SRS receiving component 199. The SRS receiving component 199 may be configured to receive SRS from a first number of SRS ports of the UE that are sequentially mapped on the second number of OFDM symbols. The second number may be greater than one. The SRS receiving component 199 may be further configured to receive PUSCH transmissions based on the SRS. Although the following description may focus on 5G NR, the concepts described herein may be applicable to other similar fields, such as LTE, LTE-A, CDMA, GSM, and other wireless technologies.

[0060] Figure 2A is a diagram 200 that illustrates an example of a first subframe within the 5G NR frame structure. Figure 2B is a diagram 230 that illustrates an example of a DL channel within a 5G NR subframe. Figure 2C is a diagram 250 that illustrates an example of a second subframe within the 5G NR frame structure. Figure 2DFIG. 280 is an illustration showing an example of UL channels within a 5G NR subframe. The 5G NR frame structure can be Frequency Division Duplexing (FDD) (where for a particular set of subcarriers (carrier system bandwidth), the subframes within that set of subcarriers are dedicated to DL or UL), or can be Time Division Duplexing (TDD) (where for a particular set of subcarriers (carrier system bandwidth), the subframes within that set of subcarriers are dedicated to both DL and UL). In Figure 2A , Figure 2C the example provided, the 5G NR frame structure is assumed to be TDD, where subframe 4 is configured with slot format 28 (where most are DL), where D is DL, U is UL, and F is flexibly available between DL / UL, and subframe 3 is configured with slot format 1 (where all are UL). Although subframes 3, 4 are shown as having slot formats 1, 28 respectively, any particular subframe can be configured with any one of the various available slot formats 0 to 61. Slot formats 0, 1 are all DL, all UL respectively. The other slot formats 2 - 61 include a mixture of DL, UL, and flexible symbols. The slot format is configured for the UE by the received Slot Format Indicator (SFI) (configured dynamically by Downlink Control Information (DCI) or semi-statically / statically by Radio Resource Control (RRC) signaling). Note that the following description also applies to the 5G NR frame structure as TDD.

[0061] Figures 2A to 2D The frame structure is illustrated, and aspects of the present disclosure can be applied to other wireless communication technologies that may have different frame structures and / or different channels. One frame (10 ms) can be divided into 10 equal-sized subframes (1 ms). Each subframe can include one or more slots. A subframe can also include mini-slots, which can include 7, 4, or 2 symbols. Each slot can include 14 or 12 symbols, depending on whether the Cyclic Prefix (CP) is normal or extended. For normal CP, each slot can include 14 symbols, and for extended CP, each slot can include 12 symbols. The symbols on the DL can be Cyclic Prefix Orthogonal Frequency Division Multiplexing (CP-OFDM) symbols. The symbols on the UL can be CP-OFDM symbols (for high throughput scenarios) or Discrete Fourier Transform (DFT) spread OFDM (DFT-s-OFDM) symbols (for power-constrained scenarios; limited to single-stream transmission). The number of slots within a subframe is based on the CP and the parameter set. The parameter set defines the Subcarrier Spacing (SCS) (see Table 1). The symbol length / duration can be scaled with 1 / SCS.

[0062]

[0063] Table 1: Parameter Set, SCS, and CP

[0064] For normal CP (14 symbols / slot), different parameter sets μ0 to 4 allow 1, 2, 4, 8, and 16 slots per subframe respectively. For extended CP, parameter set 2 allows 4 slots per subframe. Thus, for normal CP and parameter set μ, there are 14 symbols / slot and 2 μ slots / subframe. The subcarrier spacing can be equal to 2 μ *15 kHz, where μ is parameter set 0 to 4. Thus, the subcarrier spacing for parameter set μ = 0 is 15 kHz, and the subcarrier spacing for parameter set μ = 4 is 240 kHz. The symbol length / duration is negatively correlated with the subcarrier spacing. Figures 2A to 2D An example of normal CP with 14 symbols per slot and parameter set μ = 2 with 4 slots per subframe is provided. The slot duration is 0.25 ms, the subcarrier spacing is 60 kHz, and the symbol duration is approximately 16.67 μs. Within a frame set, there may be one or more different bandwidth parts (BWPs) that are frequency division multiplexed (see Figure 2B ). Each BWP can have a specific parameter set and CP (normal or extended).

[0065] A resource grid can be used to represent the frame structure. Each slot includes a resource block (RB) (also referred to as a physical RB (PRB)) that extends over 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.

[0066] As Figure 2A illustrated, some of the REs carry reference (pilot) signals (RS) for the UE. The RS can include demodulation RS (DM-RS) (designated 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 can also include beam measurement RS (BRS), beam refinement RS (BRRS), and phase tracking RS (PT-RS).

[0067] Figure 2BIllustrates examples 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 Resource Element Groups (REGs), each REG including 12 consecutive Resource Elements (REs) in an OFDM symbol of a Resource Block (RB). The PDCCH within a Bandwidth Part (BWP) can be referred to as a Control Resource Set (CORESET). The UE is configured to monitor PDCCH candidates in a PDCCH search space (e.g., common search space, UE-specific search space) during a PDCCH monitoring occasion on the CORESET, where the PDCCH candidates have different DCI formats and different aggregation levels. Additional BWPs can be located at higher and / or lower frequencies on the channel bandwidth. The Primary Synchronization Signal (PSS) can be in symbol 2 of a specific subframe of a frame. The PSS is used by the UE 104 to determine subframe / symbol timing and the physical layer identity. The Secondary Synchronization Signal (SSS) can be in symbol 4 of a specific subframe of a frame. The SSS is used by the UE to determine the 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 the Physical Cell Identifier (PCI). Based on the PCI, the UE can determine the location of the Demodulation Reference Signal (DM-RS). The Physical Broadcast Channel (PBCH) carrying the Master Information Block (MIB) can be logically grouped with the PSS and SSS to form a Synchronization Signal (SS) / PBCH block (also referred to as an SS block (SSB)). The MIB provides the number of RBs in the system bandwidth and the System Frame Number (SFN). The Physical Downlink Shared Channel (PDSCH) carries user data, broadcast system information such as System Information Blocks (SIBs) not sent via the PBCH, and paging messages.

[0068] As Figure 2C Illustrated, some of the REs carry DM-RS (denoted as R for a specific configuration, but other DM-RS configurations are possible) for channel estimation at the base station. The UE can transmit DM-RS for the Physical Uplink Control Channel (PUCCH) and the Physical Uplink Shared Channel (PUSCH). The PUSCH DM-RS can be transmitted in the previous one or two symbols of the PUSCH. Depending on whether a short PUCCH or a long PUCCH is transmitted and depending on the specific PUCCH format used, the PUCCH DM-RS can be transmitted with different configurations. The UE can transmit a Sounding Reference Signal (SRS). The SRS can be transmitted in the last symbol of a subframe. The SRS can have a comb structure, and the UE can transmit the SRS on one of the comb teeth. The SRS can be used by the base station for channel quality estimation to enable frequency-dependent scheduling of the UL.

[0069] Figure 2DExamples of various UL channels within a subframe of a frame are illustrated. The PUCCH may be located at the position indicated in one configuration. The PUCCH carries uplink control information (UCI), such as a scheduling request, a channel quality indicator (CQI), a precoding matrix indicator (PMI), a rank indicator (RI), and a hybrid automatic repeat request (HARQ) acknowledgement (ACK) (HARQ-ACK) feedback (i.e., one or more HARQ ACK bits indicating one or more ACKs and / or negative ACKs (NACKs)). The PUSCH carries data and may additionally be used to carry a buffer status report (BSR), a power headroom report (PHR), and / or UCI.

[0070] Figure 3 Is a block diagram of a base station 310 in an access network communicating with a UE 350. 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 functions. Layer 3 includes a radio resource control (RRC) layer, and layer 2 includes a service data adaptation protocol (SDAP) layer, a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, and a media access control (MAC) layer. The controller / processor 375 provides RRC layer functions associated with the broadcast of system information (e.g., MIB, SIB), RRC connection control (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release), inter-radio access technology (RAT) mobility, and measurement configuration for UE measurement reporting; PDCP layer functions associated with header compression / decompression, security (encryption, decryption, integrity protection, integrity verification), and handover support functions; RLC layer functions associated with the transfer of upper layer packet data units (PDUs), error correction via ARQ, concatenation, segmentation, and reassembly of RLC service data units (SDUs), re-segmentation of RLC data PDUs, and re-ordering of RLC data PDUs; and MAC layer functions associated with the 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 via HARQ, priority handling, and logical channel prioritization.

[0071] The transmit (TX) processor 316 and the receive (RX) processor 370 implement the layer 1 functions associated with various signal processing functions. Layer 1, which includes the physical (PHY) layer, may include error detection on the transport channel, forward error correction (FEC) encoding / decoding of the transport channel, interleaving, rate matching, mapping to the physical channel, modulation / demodulation of the physical channel, and MIMO antenna processing. The TX processor 316 handles the mapping to signal constellations based on various modulation schemes (e.g., binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), M-phase phase shift keying (M-PSK), M-quadrature amplitude modulation (M-QAM)). The encoded and modulated symbols are then split into parallel streams. Subsequently, each stream is mapped to an OFDM subcarrier, multiplexed in the time domain and / or frequency domain with a reference signal (e.g., pilot), and then combined together using an inverse fast Fourier transform (IFFT) to generate a physical channel carrying a time-domain OFDM symbol stream. The OFDM stream is precoded in space to generate multiple spatial streams. The channel estimate from the channel estimator 374 can be used to determine the encoding and modulation schemes, as well as for spatial processing. The channel estimate can be derived from the reference signals transmitted by the UE 350 and / or channel state feedback. Then, each spatial stream can be provided to a different antenna 320 via a separate transmitter 318Tx. Each transmitter 318Tx can modulate a radio frequency (RF) carrier with the corresponding spatial stream for transmission.

[0072] At the UE 350, each receiver 354Rx receives signals via its corresponding antenna 352. Each receiver 354Rx recovers the information modulated onto the RF carrier and provides the information to the receive (RX) processor 356. The TX processor 368 and the RX processor 356 implement the layer 1 functions associated with various signal processing functions. The RX processor 356 can 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 can be combined by the RX processor 356 into a single OFDM symbol stream. The RX processor 356 then uses a fast Fourier transform (FFT) to transform the OFDM symbol stream from the time domain to the frequency domain. The frequency domain signal includes a separate OFDM symbol stream for each subcarrier of the OFDM signal. The symbols and reference signals on each subcarrier are recovered and demodulated by determining the most likely signal constellation point transmitted by the base station 310. These soft decisions can be based on the channel estimate computed by the channel estimator 358. Then, the soft decisions are decoded and deinterleaved to recover the data and control signals 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 the layer 3 and layer 2 functions.

[0073] The controller / processor 359 may be associated with at least one memory 360 that stores program code 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 the transport channel and the logical channel, packet reassembly, decryption, header decompression, and control signal processing to recover IP packets. The controller / processor 359 is also responsible for error detection using the ACK and / or NACK protocols to support HARQ operations.

[0074] Similar to the functions described in connection with DL transmissions performed by the base station 310, the controller / processor 359 provides RRC layer functions associated with system information (e.g., MIB, SIB) acquisition, RRC connection, and measurement reporting; PDCP layer functions associated with header compression / decompression and security (encryption, decryption, integrity protection, integrity verification); RLC layer functions associated with the transfer of upper layer PDUs, error correction via ARQ, concatenation, segmentation, and reassembly of RLC SDUs, re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functions associated with the mapping between the logical channel and the transport channel, multiplexing of MAC SDUs onto TBs, demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction via HARQ, priority handling, and logical channel prioritization.

[0075] Channel estimates derived by the channel estimator 358 based on reference signals or feedback transmitted by the base station 310 may be used by the TX processor 368 to select appropriate decoding 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 a separate transmitter 354Tx. Each transmitter 354Tx modulates an RF carrier with the corresponding spatial stream for transmission.

[0076] UL transmissions are processed at the base station 310 in a manner similar to that described in connection with the receiver functions at the UE 350. Each receiver 318Rx receives signals via its corresponding antenna 320. Each receiver 318Rx recovers the information modulated onto the RF carrier and provides the information to the RX processor 370.

[0077] The controller / processor 375 may be associated with at least one memory 376 that stores program code 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 the transport channel and the logical channel, packet reassembly, decryption, header decompression, control signal processing to recover IP packets. The controller / processor 375 is also responsible for error detection using the ACK and / or NACK protocols to support HARQ operations.

[0078] At least one of TX processor 368, RX processor 356, and controller / processor 359 may be configured to perform aspects of SRS mapping component 198 in conjunction with Figure 1 thereof.

[0079] At least one of TX processor 316, RX processor 370, and controller / processor 375 may be configured to perform aspects of SRS reception component 199 in conjunction with Figure 1 thereof.

[0080] As wireless communication technology evolves, additional types of UEs including UEs with multiple antennas may be supported. Some UEs may be referred to as "advanced UEs", and these UEs may include smart phones, indoor CPEs, outdoor CPEs, FWA CPEs, vehicles, industrial devices, laptops, larger-sized devices, etc. Compared to non-advanced UEs, advanced UEs may be associated with higher reliability and / or improved efficiency. Advanced UEs may include multiple antenna elements, including four antennas or more than four antennas, such as eight antenna elements, etc. The UE may support more than four downlink layers and / or four uplink transmission ports. Advanced UEs may also support DM-RS, sounding reference signal (SRS), and / or codebook design.

[0081] For advanced UEs (e.g., mobile devices, larger-sized devices, etc.), an increasing number of transmit antennas (Tx) (e.g., more than four transmit antennas) are being considered, and support for 8-port transmission (e.g., uplink transmission, downlink transmission, or sidelink transmission) may improve wireless communication performance.

[0082] Figure 4 An example UE 400 communicating (e.g., uplink transmission and downlink transmission) with network node 450 as presented herein is illustrated. In some aspects, UE 400 may communicate with a second UE 451 using sidelink communication, for example. UE 400 may be similar to Figure 1 UE 104 of Figure 3 and / or Figure 1 UE 350 of

[0083] Network node 450 may be similar to base station 102 or components of base station 102, such as Figure 4In [the example], the exemplary UE 400 includes eight antenna elements (e.g., the first antenna element 402a, the second antenna element 402b, the third antenna element 402c, the fourth antenna element 402d, the fifth antenna element 402e, the sixth antenna element 402f, the seventh antenna element 402g, and the eighth antenna element 402h). The antenna elements may be collectively referred to herein as "antenna elements 402". The antenna elements may be referred to as antennas, antenna ports, or ports. Although the exemplary UE 400 is illustrated as having eight antenna elements, in other examples, the UE may include fewer antenna elements or more antenna elements.

[0084] In Figure 4 the illustrated example, the antenna elements 402 are located on different parts of the UE 400 to form diversity and provide directional communication. The UE 400 may use at least one of the antenna elements 402 to transmit a communication signal (e.g., an SRS signal) so that the network node 450 can estimate the uplink channel. The UE 400 includes a baseband 404 and a transmission path 406 for uplink transmission using one or more of the antenna elements 402. Aspects of the baseband 404 may be implemented by Figure 3 the TX processor 368 and / or the processor 359 of the UE 350. The transmission path 406 includes eight exemplary transmission chains (e.g., the first transmission chain 408a, the second transmission chain 408b, the third transmission chain 408c, the fourth transmission chain 408d, the fifth transmission chain 408e, the sixth transmission chain 408f, the seventh transmission chain 408g, and the eighth transmission chain 408h). The transmission chains may also be referred to as RF chains. The transmission chains of the UE 400 may be collectively referred to herein as "transmission chains 408". Although the exemplary UE 400 is illustrated as having eight transmission chains, in other examples, the UE may include fewer transmission chains or more transmission chains. Each transmission chain may be configured to convert a baseband signal into an RF signal for transmission.

[0085] The UE 400 may probe ports by transmitting SRS using a combination of the transmission chains. In Figure 4 the example, the UE 400 includes eight exemplary ports 410 (e.g., the first port 410a, the second port 410b, the third port 410c, the fourth port 410d, the fifth port 410e, the sixth port 410f, the seventh port 410g, and the eighth port 410h). The ports may be collectively referred to herein as "ports 410". Although the exemplary UE 400 is illustrated as having eight ports, in other examples, the UE may include fewer ports or more ports.

[0086] UE 400 can support three levels of coherence: full coherence, partial coherence, and incoherence. A UE with full coherence can be referred to as a full-coherence UE and can transmit coherently on all antenna elements 402. A full-coherence UE has the ability to control the relative phase between the transmit chains 408 of the UE 400. The two antenna elements maintain a relative phase when the phases across these two antennas are locked and / or remain the same across the uplink transmission.

[0087] A UE with partial coherence can be referred to as a partial-coherence UE and can transmit coherently on pairs of antenna elements. A partial-coherence UE has the ability to maintain a relative phase across multiple subsets of the antenna elements 402. For example, the first coherent antenna pair 414 can include the first antenna element 402a and the fourth antenna element 402d, and the second coherent antenna pair 416 can include the second antenna element 402b and the third antenna element 402c. The antenna elements of the corresponding coherent antenna pairs can be coherent antennas relative to each other and can maintain a relative phase across the two corresponding antenna elements. However, a partial-coherence UE may not be able to maintain phase coherence across these two pairs.

[0088] A UE with incoherence can be referred to as an incoherence UE and may not be able to transmit coherently on any pair of antenna elements or set of antenna elements. For example, an incoherence UE may lack the ability to maintain a relative phase across any of the antenna elements 402.

[0089] In Figure 4 the example of, UE 400 can support multi-layer uplink transmission. For an incoherence UE, each layer of the multi-layer uplink transmission is transmitted to a single antenna element among the antenna elements 402, and there is no combination across layers. For a partial-coherence UE, certain antenna elements are combined and each layer is transmitted to multiple ports. A partial-coherence UE can be configured as a partial-coherence 2Tx (PC-2) UE or a partial-coherence 4Tx (PC-4) UE. For a PC-2 UE, each layer of the uplink transmission is transmitted to two antenna elements among the antenna elements 402, and for a PC-4 UE, each layer of the uplink transmission is transmitted to four antenna elements among the antenna elements 402. For a full-coherence UE, each layer is transmitted to each of the antenna elements 402.

[0090] The UE 400 may be configured to apply the precoder 412 across all subbands transmitted on the uplink, or may be configured to apply multiple precoders for multiple subbands transmitted on the uplink. The network node 450 may configure the UE 400 with one or more precoder configurations. Additionally or alternatively, the network node 450 may activate the precoder configuration at the UE 400. The UE 400 may receive the precoder configuration via RRC signaling, downlink control information (DCI), and / or a MAC-control element (MAC-CE).

[0091] UL DM-RS, SRS, SRS Resource Indicator (SRI), and Transmit Precoding Matrix Indicator (TPMI) (including codebook) may be enhanced to enable 8Tx UL operation, supporting four or more layers per UE in the UL for CPE / FWA / vehicle / industrial equipment.

[0092] For a single SRS resource in an SRS resource set using a "codebook" for 8Tx PUSCH or an "antenna switching" scheme (i.e., for eight transmitters and eight receivers with antenna switching), when the SRS resource is configured with eight ports and m OFDM symbols (m>1), the eight ports can be mapped to m OFDM symbols. For example, different SRS ports can be mapped to different OFDM symbols (i.e., time division multiplexing (TDM)), and m can be 2, 4, 8, 10, etc.

[0093] In some aspects, multiple SRS ports may be sequentially mapped to multiple OFDM symbols. For example, multiple SRS ports for 8Tx may be sequentially mapped to multiple symbols, such as 1, 2, 4, or 8 OFDM symbols. In one example, eight SRS ports may be mapped to two OFDM symbols. Figure 5A FIG5 is a diagram 500 illustrating an example mapping of eight SRS ports to two OFDM symbols according to various aspects of the present disclosure. Figure 5A As shown, a subset of SRS ports (e.g., SRS ports 1000, 1001, 1002, and 1003) can be mapped to resources of a first OFDM symbol S1, and a different subset of SRS ports (e.g., SRS ports 1004, 1005, 1006, and 1007) can be mapped to resources of a second OFDM symbol S2. In this disclosure, "mapping an SRS port to a resource of a symbol" may also be referred to as "mapping to a symbol." In another example, eight SRS ports can be mapped to four OFDM symbols. Figure 5B FIG5 is a diagram 550 illustrating an example mapping of eight SRS ports to four OFDM symbols according to various aspects of the present disclosure. Figure 5BAs shown, a first subset of SRS ports (e.g., SRS ports 1000, 1001) can be mapped to the first OFDM symbol S1, a second subset of SRS ports (e.g., SRS ports 1002, 1003) can be mapped to the second OFDM symbol S2, a third subset of SRS ports (e.g., SRS ports 1004, 1005) can be mapped to the third OFDM symbol S3, and a fourth subset of SRS ports (e.g., SRS ports 1006, 1007) can be mapped to the fourth OFDM symbol S4. In another example, eight SRS ports can be sequentially mapped to eight OFDM symbols. For example, SRS port 1000 can be mapped to the first OFDM symbol, SRS port 1001 can be mapped to the second OFDM symbol, SRS port 1002 can be mapped to the third OFDM symbol, SRS port 1003 can be mapped to the fourth OFDM symbol, SRS port 1004 can be mapped to the fifth OFDM symbol, SRS port 1005 can be mapped to the sixth OFDM symbol, SRS port 1006 can be mapped to the seventh OFDM symbol, and SRS port 1007 can be mapped to the eighth OFDM symbol.

[0094] In some aspects, when mapping eight SRS ports to multiple OFDM symbols, depending on SRS usage and codebook / precoder coherence, the SRS ports can be mapped to consecutive or non - consecutive OFDM symbols. For example, if the use of eight SRS ports is for codebook - based 8Tx PUSCH and the codebook / precoder is coherent, then the eight SRS ports can be mapped to, for example, M consecutive OFDM symbols and not to non - consecutive symbols. As another example, if the use of eight SRSs is for codebook - based 8Tx PUSCH and the codebook / precoder is partially coherent, then the SRS ports belonging to the same coherent SRS port group can be mapped to a set of consecutive OFDM symbols (e.g., rather than non - consecutive symbols), while the non - coherent SRS ports (e.g., belonging to different coherent SRS port groups) can be mapped to non - consecutive or consecutive OFDM symbols. Figure 6A An example mapping is illustrated, which shows that coherent SRS ports (e.g., within a coherent SRS port group) are mapped to consecutive symbols, while the mapping between groups can be consecutive or non - consecutive.

[0095] In another example, if the use of eight SRS ports is for codebook-based 8Tx PUSCH and the codebook / precoder is non-coherent, the eight SRS ports can be mapped to M discontinuous or M continuous OFDM symbols. In another example, if the use of eight SRS ports is for codebook-based 8Tx PUSCH and the codebook / precoder is an antenna switching scheme, the eight SRS ports can be mapped to M discontinuous or M continuous OFDM symbols.

[0096] Figure 6A FIG. 600 is a diagram illustrating an example SRS port mapping to multiple OFDM symbols. In Figure 6A the example, the use of eight SRS ports is for codebook-based 8Tx PUSCH and the codebook / precoder is partially coherent. As Figure 6A shown, the eight SRS ports (1000, 1001, ....... 1006 and 1007) can be divided into two coherent SRS port groups. The first coherent SRS port group can include SRS ports 1000, 1001, 1002, and 10...... The second coherent SRS port group can include SRS ports 1004, 1005, 1006, and 1007. The SRS ports in each of these coherent SRS port groups can be mapped to continuous OFDM symbols, e.g., and not to discontinuous symbols. For example, SRS port 1000 and SRS port 1001 can be mapped to OFDM symbol S1, and SRS port 1002 and SRS port 1003 can be mapped to OFDM symbol S2. OFDM symbol S1 and OFDM symbol S2 can be continuous OFDM symbols. SRS port 1004 and SRS port 1005 can be mapped to OFDM symbol S3, and SRS port 1006 and SRS port 1007 can be mapped to OFDM symbol S4. OFDM symbol S3 and OFDM symbol S4 can be continuous OFDM symbols. On the other hand, SRS ports belonging to different SRS port groups can be mapped to continuous or discontinuous OFDM symbols. For example, SRS port 1002 and SRS port 1003 can be mapped to OFDM symbol S2, and SRS port 1004 and SRS port 1005 can be mapped to OFDM symbol S3. In one example, OFDM symbol S2 and OFDM symbol S3 can be discontinuous OFDM symbols. In another example, OFDM symbol S2 and OFDM symbol S3 can be continuous OFDM symbols.

[0097] In some aspects, when mapping eight SRS ports to multiple OFDM symbols, depending on SRS usage and codebook / precoder coherence, the SRS ports can be mapped to OFDM symbols in the same time slot / sub - time slot or different time slots / sub - time slots. For example, if the usage of the eight SRS ports is for codebook - based 8Tx PUSCH and the codebook / precoder is coherent, then the eight SRS ports can be mapped to M OFDM symbols in the same time slot or the same sub - time slot, e.g., and not to symbols in different time slots or different sub - time slots. In another example, if the usage of the eight SRSs is for codebook - based 8Tx PUSCH and the codebook / precoder is partially coherent, then the SRS ports belonging to the same coherent SRS port group can be mapped to a set of OFDM symbols in the same time slot or the same sub - time slot, e.g., and not to different time slots or different sub - time slots, while the SRS ports belonging to different coherent SRS port groups can be mapped to OFDM symbols in the same time slot / sub - time slot or different time slots / sub - time slots, e.g., as illustrated in Figure 6B In another example, if the usage of the eight SRS ports is for codebook - based 8Tx PUSCH and the codebook / precoder is non - coherent, then the eight SRS ports can be mapped to M OFDM symbols in the same time slot / sub - time slot or different time slots / sub - time slots. If the usage of the eight SRS ports is for codebook - based 8Tx PUSCH and the codebook / precoder is an antenna switching scheme, then the eight SRS ports can be mapped to M OFDM symbols in the same time slot / sub - time slot or different time slots / sub - time slots.

[0098] Figure 6B FIG. 650 is a diagram illustrating an example mapping of multiple SRS ports to multiple OFDM symbols. In Figure 6B the example of Figure 6BAs shown, eight SRS ports (1000, 1001, 1002, 1003, 1004, 1005, 1006, and 1007) can be divided into two coherent SRS port groups. The first coherent SRS port group can include SRS ports 1000, 1001, 1002, and 1003, and the second coherent SRS port group can include SRS ports 1004, 1005, 1006, and 1007. The SRS ports in each of these coherent SRS port groups can be mapped to OFDM symbols in the same time slot / sub - time slot, for example, and are not mapped to different time slots / sub - time slots. For example, SRS port 1000 and SRS port 1001 can be mapped to OFDM symbol S1, and SRS port 1002 and SRS port 1003 can be mapped to OFDM symbol S2. OFDM symbol S1 and OFDM symbol S2 can be in the same time slot / sub - time slot. SRS port 1004 and SRS port 1005 can be mapped to OFDM symbol S3, and SRS port 1006 and SRS port 1007 can be mapped to OFDM symbol S4. OFDM symbol S3 and OFDM symbol S4 can be in the same time slot / sub - time slot. On the other hand, SRS ports belonging to different SRS port groups can be mapped to OFDM symbols in the same time slot / sub - time slot or in different time slots / sub - time slots. For example, SRS port 1002 and SRS port 1003 are mapped to OFDM symbol S2, and SRS port 1004 and SRS port 1005 are mapped to OFDM symbol S3. In one example, OFDM symbol S2 and OFDM symbol S3 can be in the same time slot / sub - time slot. In another example, OFDM symbol S2 and OFDM symbol S3 can be in different time slots / sub - time slots.

[0099] When mapping eight SRS ports to multiple OFDM symbols, SRS repetition can be implemented in various ways. For example, assume that a repetition factor X is configured for an SRS resource with eight SRS ports. M OFDM symbols can be configured for this SRS resource, and SRS repetition when mapping eight SRS ports to M OFDM symbols can be implemented in the following two configurations.

[0100] In the first configuration, the eight SRS ports can first be mapped to M / X OFDM symbols. Then, the mapping can be repeated X times. Figure 7A FIG. 700 is a diagram illustrating an example SRS repetition when mapping eight SRS ports to eight OFDM symbols according to various aspects of the present disclosure. In Figure 7A the example, the repetition factor X = 2, M = 8. As Figure 7AAs shown, eight SRS ports (1000, 1001, 1002, 1003, 1004, 1005, 1006, and 1007) can be mapped to the first four (M / X = 4) OFDM symbols (i.e., S1, S2, S3, and S4). When mapping the first four OFDM symbols, the first two SRS ports 1000, 1001 can be mapped to the first OFDM symbol S1, the next two SRS ports 1002, 1003 can be mapped to the second OFDM symbol S2, the next two SRS ports 1004, 1005 can be mapped to the third OFDM symbol S3, and the last two SRS ports 1006, 1007 can be mapped to the fourth OFDM symbol S4. Then, the mapping on the first four OFDM symbols (S1, S2, S3, and S4) can be repeated on the next four OFDM symbols (S5, S6, S7, and S8), as Figure 7A shown. That is, the mapping from the eight SRS ports (1000, 1001, 1002, 1003, 1004, 1005, 1006, and 1007) to the four OFDM symbols can be repeated for a time specified by the repetition factor (i.e., 2 times) on the eight OFDM symbols.

[0101] In the second configuration, the first 8X / M SRS ports can be mapped to the first OFDM symbol, and the mapping of the first 8X / M SRS ports can be repeated X times. Then, the second 8X / M ports can be mapped to the (X + 1)th OFDM symbol, and the mapping of the second 8X / M SRS ports can be repeated X times. This process can continue until all SRS ports and OFDM symbols have been mapped. Figure 7B FIG. 750 is a diagram illustrating an example SRS repetition when mapping eight SRS ports to eight OFDM symbols in accordance with various aspects of the present disclosure. In Figure 7B the example, the repetition factor X = 2 and M = 8. As Figure 7B shown, the first group of two (8X / M = 2) SRS ports (i.e., SRS ports 1000, 1001) can be mapped to the first OFDM symbol S1, and the mapping of the first group of two SRS ports can be repeated twice (on OFDM symbol S1 and OFDM symbol S2). Then, the second group of two SRS ports (SRS ports 1002, 1003) can be mapped to the third OFDM symbol S3, and the mapping of the second group of two SRS ports can be repeated twice (on OFDM symbol S3 and OFDM symbol S4). This process can continue until each of the SRS ports and OFDM symbols has been mapped.

[0102] In wireless communication, PUSCH transmission can be associated with the most recent transmission of the SRS resource indicated by the SRI. Figure 8AFIG. 800 illustrates the association of PUSCH transmissions with SRS resources. As Figure 8A shown, SRS resource 1 may be transmitted in time slots n-4 and n-2, and SRS resource 2 may be transmitted in time slots n-3 and n-1. In time slot n, the SRI in the DCI may indicate that the PUSCH transmission may be associated with SRS resource 1, and the UE may associate the PUSCH transmission with the most recent SRS resource 1 transmission in the past (i.e., on time slot n-2).

[0103] Figure 8B FIG. 850 illustrates the association of PUSCH transmissions with SRS resources. As Figure 8B shown, if the most recent transmission of the corresponding SRS resource is discarded, for example, due to a conflict of the SRS with other higher-priority channels (e.g., temporal overlap with other higher-priority channels), the UE may associate the PUSCH transmission with a previous transmission of the SRS resource. For example, as Figure 8B shown, if the SRS resource 1 transmission in time slot n-2 is discarded, the UE may associate the PUSCH transmission with the previous SRS resource 1 transmission closest to the discarded transmission, which is the SRS resource 1 transmission in time slot n-4, as Figure 8B shown.

[0104] When eight SRS ports are mapped to multiple OFDM symbols, the discarded SRS may be partially discarded (e.g., discard a part of the SRS resources of the SRS resource transmission in a time slot, but not discard all of the SRS resource transmissions) or completely discarded (e.g., discard all of the SRS resource transmissions in a time slot). In the present disclosure, the discarded SRS may be referred to as an SRS that is "skipped or not transmitted". When partial SRS discarding occurs (e.g., a part of the SRS resource transmission in a time slot has been discarded), depending on the SRS usage and the PUSCH codebook / precoder coherence, the remaining partial SRS resource transmissions may be disposed of in various ways as to whether they will be associated with future PUSCH transmissions. In one configuration, when a part of the SRS resource transmission in a time slot is discarded, the other parts of the SRS resource transmission in the same time slot may also be considered discarded (e.g., the partially discarded SRS may be regarded as having been completely discarded). Figure 9A FIG. 900 illustrates the association of PUSCH transmissions with SRS resources in partial SRS resource discarding according to various aspects of the present disclosure. In Figure 9AIn an example, the SRI in the DCI may indicate that the PUSCH transmission is associated with SRS resource 1. When the SRS ports 4 - 7 in the most recent SRS resource 1 transmission (i.e., slot n - 2) are discarded, the remaining SRS ports in slot n - 2 (i.e., SRS ports 0 - 3) may also be considered discarded, and the PUSCH transmission will be associated with the earlier SRS resource 1 transmission closest to slot n - 2, which is the SRS resource transmission on slot n - 4, as Figure 9A shown.

[0105] In another configuration, when a part of the SRS resource transmission in a slot is discarded, the other parts of the SRS resource transmission in the same slot may not be considered discarded. Figure 9B FIG. 950 is a diagram illustrating the association of PUSCH transmission with SRS resources in partial SRS resource discarding according to various aspects of the present disclosure. In Figure 9B an example, the SRI in the DCI may indicate that the PUSCH transmission is associated with SRS resource 1. When the SRS ports 4 - 7 in the most recent SRS resource 1 transmission (i.e., slot n - 2) are discarded, the remaining SRS ports in slot n - 2 (i.e., SRS ports 0 - 3) may not be considered discarded and may remain associated with the PUSCH transmission. Due to the discarded SRS ports 4 - 7 in slot n - 2, the PUSCH transmission will be associated with the SRS ports 4 - 7 in the earlier SRS resource 1 transmission closest to slot n - 2, which are the SRS ports 4 - 7 on slot n - 4, as Figure 9B shown.

[0106] Depending on the SRS usage and the PUSCH codebook / pre - decoder coherence, discarding a subset of eight SRS ports may be considered partial discarding or complete discarding. In some examples, if the use of eight SRS ports is for codebook - based 8Tx PUSCH and the codebook / pre - decoder is coherent, the partial discarding may be considered complete discarding. For example, referring to Figure 9A , the partial discarding of SRS ports 4 - 7 on slot n - 2 may be considered complete discarding on slot n - 2 (i.e., the SRS ports 0 - 3 on slot n - 2 are also considered discarded), and the PUSCH transmission will be associated with the SRS ports 0 - 7 in the earlier SRS resource 1 transmission closest to the discarded transmission.

[0107] In some examples, if the use of eight SRS ports is for codebook - based 8Tx PUSCH and the codebook / pre - decoder is partially coherent, the partial discarding may not be considered complete discarding. In one configuration, only the SRS ports in the same coherence group as the discarded SRS ports may be considered discarded. Figure 10AFIG. 1030 illustrates the association of PUSCH transmission with SRS resources in partial SRS resource discarding. In Figure 10A the example, SRS ports 0-3 are in one coherent group, SRS ports 4-7 are in another coherent group, and the SRI in the DCI indicates that the PUSCH transmission is associated with SRS resource 1. When SRS ports 4-5 in slot n-2 are discarded, only the SRS ports in the same coherent group as the discarded SRS ports in slot n-2 (i.e., SRS ports 6-7) are considered discarded, while the other SRS ports (i.e., SRS ports 0-3) are not considered discarded. Therefore, after SRS ports 4-5 in slot n-2 are discarded, the PUSCH transmission is associated with SRS ports 0-3 in slot n-2 and SRS ports 4-7 in slot n-4, as Figure 10A shown.

[0108] In some examples, if the use of eight SRS ports is for codebook-based 8Tx PUSCH and the codebook / precoder is non-coherent, partial discarding may not be considered complete discarding, and only the physically discarded SRS ports can be considered discarded. In some examples, if the use of eight SRS ports is for codebook-based 8Tx PUSCH and the codebook / precoder is for an antenna switching scheme, partial discarding may not be considered complete discarding, and only the physically discarded SRS ports can be considered discarded. Figure 10B FIG. 1050 illustrates the association of PUSCH transmission with SRS resources in partial SRS resource discarding. In Figure 10B the example, SRS ports 0-3 are in one coherent group, SRS ports 4-7 are in another coherent group, and the SRI in the DCI indicates that the PUSCH transmission is associated with SRS resource 1. As Figure 10B shown, when SRS ports 4-5 in slot n-2 are discarded, only the physically discarded SRS ports are considered discarded, while all other SRS ports in slot n-2 (i.e., ports 0-3 and ports 6-7) are not considered discarded. Therefore, after SRS ports 4-5 in slot n-2 are discarded, the PUSCH transmission is associated with SRS ports 0-3 and SRS ports 6-7 in slot n-2 and SRS ports 4-5 in slot n-4, as Figure 10B shown.

[0109] Figure 11Call flow diagram 1100 illustrates a method of wireless communication in accordance with various aspects of the present disclosure. Although aspects are described with respect to base station 1104, these aspects may be performed by base stations in a cluster and / or by one or more components of base station 1104 (e.g., CU 110, DU 130, and / or RU 140).

[0110] As Figure 11 shown, at 1106, UE 1102 may sequentially map a first number of SRS ports to a second number of OFDM symbols. The first number and the second number may each be greater than one. In one example, in accordance with Figure 6A , UE 1102 may sequentially map eight SRS ports to four OFDM symbols. In another example, in accordance with Figure 7A or Figure 7B , UE 1102 may sequentially map eight SRS ports to eight OFDM symbols.

[0111] At 1108, UE 1102 may transmit SRS from the first number of SRS ports on the second number of OFDM symbols based on the mapping.

[0112] At 1110, UE 1102 may associate a PUSCH transmission with the most recent transmission of an SRS resource indicated by an SRI that does not include a skipped transmission of at least one SRS port of the first number of SRS ports. For example, referring to Figure 9A , the UE may associate a PUSCH transmission (on slot n + 1) with the transmission of SRS resource 1 at slot n - 4. SRS resource 1 is indicated by an SRI at slot n, and slot n - 4 does not include a skipped transmission of at least one SRS port of the eight SRS ports.

[0113] At 1112, UE 1102 may determine whether to use a partial SRS transmission for a PUSCH transmission based on one or more of SRS usage, a codebook, or coherence. For example, the UE may determine whether to use a partial SRS transmission (e.g., an SRS transmission on ports 0 - 3 at slot n - 2) for a PUSCH transmission based on whether the SRS usage is for codebook-based 8Tx PUSCH and the coherence of the codebook / precoder, as Figure 9B shown.

[0114] At 1114, UE 1102 may discard all of the first number of SRS ports in response to the discard of at least one SRS port of the first number of SRS ports communicating with base station 1104. For example, as Figure 9AAs shown, the UE may discard all eight SRS ports (SRS ports 0-7 in slot n-2) in response to the discard of at least one SRS port among the eight SRS ports communicating with the base station (i.e., the discard of SRS ports 4-7 in slot n-2).

[0115] At 1116, UE 1102 may continue communication with base station 1104 using the SRS ports that have not been discarded in response to the discard of at least one SRS port among the fourth quantity of SRS ports communicating with base station 1104. For example, referring to Figure 10B , the UE may continue communication with the network entity using the SRS ports that have not been discarded (e.g., SRS ports 0-3 and SRS ports 6-7 in slot n-2) in response to the discard of at least one SRS port among the fourth quantity of SRS ports communicating with the base station (e.g., the discard of SRS ports 4-5 in slot n-2).

[0116] At 1118, UE 1102 may continue communication with base station 1104 using the SRS ports that have not been discarded in response to the discard of at least one SRS port among the first quantity of SRS ports communicating with the base station. For example, referring to Figure 10B , the UE may continue communication with the base station using the SRS ports that have not been discarded (e.g., SRS ports 0-3 and SRS ports 6-7 in slot n-2) in response to the discard of at least one SRS port among the first quantity of SRS ports communicating with the base station (e.g., the discard of SRS ports 4-5 in slot n-2).

[0117] At 1120, UE 1102 may transmit a PUSCH transmission to base station 1104.

[0118] Figure 12 FIG. 1200 is a flow chart illustrating a method of wireless communication at a UE in accordance with various aspects of the present disclosure. The method may be performed by a UE. The UE may be Figure 16 UE 104, 350, 1102 or apparatus 1604 in a hardware implementation thereof. The method implements or enhances 8Tx UL operation to support four and more layers per UE in the UL for the device. Thus, the aspects presented herein improve the efficiency of wireless communication.

[0119] As Figure 12 shown, at 1202, the UE may sequentially map a first quantity of SRS ports to a second quantity of OFDM symbols. The first quantity and the second quantity may each be greater than one. The network entity may be Figure 1 a base station or a component of a base station in an access network, or a core network component (e.g., base stations 102, 310, 1104; or Figure 16in the hardware implementation of Network Entity 1602). Figure 5A and Figure 5B and Figure 6A and Figure 6B and Figure 7A and Figure 7B and Figure 8A and Figure 8B and Figure 9A and Figure 9B and Figure 10A and Figure 10B and Figure 11 illustrate various aspects of the steps in conjunction with Flowchart 1200. For example, referring to Figure 11 , at 1106, UE 1102 may sequentially map a first number of SRS ports to a second number of OFDM symbols. In one example, referring to Figure 6A , the UE may sequentially map eight SRS ports to four OFDM symbols. In another example, referring to Figure 7B , the UE may sequentially map eight SRS ports to eight OFDM symbols. In some aspects, 1202 may be performed by the SRS mapping component 198.

[0120] At 1204, the UE may transmit SRS from a first number of SRS ports on a second number of OFDM symbols based on the mapping. For example, referring to Figure 11 , at 1108, UE 1102 may transmit SRS from a first number of SRS ports on a second number of OFDM symbols based on the mapping performed at 1106. In some aspects, 1204 may be performed by the SRS mapping component 198.

[0121] Figure 13 is Flowchart 1300 illustrating a method of wireless communication at a UE according to various aspects of the present disclosure. The method may be performed by a UE. The UE may be Figure 16 UE 104, 350, 1102 or Device 1604 in the hardware implementation of.

[0122] As Figure 13 shown, at 1302, the UE may sequentially map a first number of SRS ports to a second number of OFDM symbols. The first number and the second number may each be greater than one. The network entity may be Figure 1 a base station or a component of a base station in an access network, or a core network component (e.g., base station 102, 310, 1104; or Figure 16 Network Entity 1602 in the hardware implementation of). Figure 5A and Figure 5B andFigure 6A , [[ID= , ​ , ​ , ​ , ​ , ​ , ​ , ​ , ​ and ​ illustrate various aspects of the steps in conjunction with flowchart 1300. For example, referring to ​ , at 1106, UE 1102 may sequentially map a first number of SRS ports to a second number of OFDM symbols. In one example, referring to ​ , the UE may sequentially map eight SRS ports to four OFDM symbols. In another example, referring to ​ , the UE may sequentially map eight SRS ports to eight OFDM symbols. In some aspects, 1302 may be performed by SRS mapping component 198.

[0123] At 1304, the UE may transmit SRS from the first number of SRS ports on the second number of OFDM symbols based on the mapping. For example, referring to ​ , at 1108, UE 1102 may transmit SRS from the first number of SRS ports on the second number of OFDM symbols based on the mapping performed at 1106. In some aspects, 1304 may be performed by SRS mapping component 198.

[0124] In some aspects, the SRS ports may be based on a codebook. A first subset of the SRS ports may be coherent and a second subset of the SRS ports may be coherent. The first subset of the SRS ports may be non - coherent with the second subset of the SRS ports. For example, referring to ​ , a first subset of the SRS ports (SRS ports 1000 - 1003) may be coherent and a second subset of the SRS ports (SRS ports 1004 - 1007) may be coherent. The first subset of the SRS (SRS ports 1000 - 1003) may be non - coherent with the second subset of the SRS ports (SRS ports 1004 - 1007).

[0125] In some aspects, in order to (at 1302) sequentially map a first number of SRS ports to a second number of OFDM symbols, at 1322, the UE may map a first subset of the SRS ports to a first consecutive subset of the OFDM symbols; and map a second subset of the SRS ports to a second consecutive subset of the OFDM symbols. For example, referring to ​, the UE may map a first subset of SRS ports (SRS ports 1000 - 1003) to a first consecutive subset of OFDM symbols (S1, S2); and map a second subset of SRS ports (SRS ports 1004 - 1007) to a second consecutive subset of OFDM symbols (S3, S4). In some aspects, 1322 may be performed by the SRS mapping component 198.

[0126] In some aspects, the first consecutive subset of OFDM symbols may be consecutive or non - consecutive with the second consecutive subset of OFDM symbols. For example, referring to ​ , the first consecutive subset of OFDM symbols may be OFDM symbol S1 and OFDM symbol S2, and the second consecutive subset of OFDM symbols may be OFDM symbol S3 and OFDM symbol S4. The first consecutive subset of OFDM symbols (S1 and S2) may be consecutive or non - consecutive with the second consecutive subset of OFDM symbols (S3 and S4).

[0127] In some aspects, based on the first number of SRS ports being a coherent SRS port group, the first number of SRS ports may be mapped to a second number of OFDM symbols within the same time slot or sub - time slot. For example, referring to ​ , based on the first number of SRS ports being a coherent SRS port group, the first number of SRS ports (SRS ports 1000 - 1003) may be mapped to a second number of OFDM symbols (S1 and S2) within the same time slot or sub - time slot.

[0128] In some aspects, in order to (at 1302) sequentially map the first number of SRS ports to the second number of OFDM symbols, at 1324, the UE may map a non - coherent SRS port group among the first number of SRS ports to different time slots or sub - time slots. For example, referring to ​ , the UE may map SRS port 1002 and SRS port 1003 to OFDM symbol S2, and map SRS port 1004 and SRS port 1005 to OFDM symbol S3. OFDM symbol S2 and OFDM symbol S3 may be in different time slots or sub - time slots. In some aspects, 1324 may be performed by the SRS mapping component 198.

[0129] In some aspects, the use of the first number of SRS ports may be for codebook - based PUSCH, and the codebook for the first number of SRS ports may be used for an antenna switching scheme. In order to (at 1302) sequentially map the first number of SRS ports to the second number of OFDM symbols, at 1326, the UE may map the first number of SRS ports to consecutive or non - consecutive symbols based on the antenna switching scheme. For example, referring to ​, the UE may map eight SRS ports (SRS ports 1000 - 1007) to two OFDM symbols (S1 and S2). If the use of the eight SRS ports is for codebook - based PUSCH and the codebook for the eight SRS ports is used for an antenna switching scheme, the two OFDM symbols (S1 and S2) may be consecutive or non - consecutive symbols. In some aspects, 1326 may be performed by the SRS mapping component 198.

[0130] In some aspects, the use of the first number of SRS ports may be for codebook - based PUSCH and the codebook for the first number of SRS ports may be used for an antenna switching scheme. To (at 1302) sequentially map the first number of SRS ports to the second number of OFDM symbols, at 1328, the UE may map the first number of SRS ports to the same time slot, the same sub - slot, different time slots, or different sub - slots based on the antenna switching scheme. For example, referring to ​ , the UE may map eight SRS ports (SRS ports 1000 - 1007) to two OFDM symbols (S1 and S2). If the use of the eight SRS ports is for codebook - based PUSCH and the codebook for the eight SRS ports is used for an antenna switching scheme, the two OFDM symbols (S1 and S2) may be in the same time slot, the same sub - slot, different time slots, or different sub - slots. In some aspects, 1328 may be performed by the SRS mapping component 198.

[0131] In some aspects, to (at 1302) sequentially map the first number of SRS ports to the second number of OFDM symbols, at 1330, the UE may map the first number of SRS ports to a subset of the second number of symbols. The subset of the second number of symbols may be based on the second number of symbols divided by a repetition factor. In some examples, the mapping from the first number of SRS ports to the subset of the second number of symbols may be repeated for the time specified by the repetition factor on the second number of symbols. For example, referring to ​ , when sequentially mapping the first number (i.e., 8) of SRS ports (SRS ports 1000 - 1007) to the second number (i.e., 8) of OFDM symbols (S1 - S8), assuming the repetition factor is 2, the UE may map the first number (i.e., 8) of SRS ports (SRS ports 1000 - 1007) to a subset of the second number of symbols (i.e., symbols S1 - S4). The subset of the second number of symbols may be based on the second number of symbols (i.e., 8) divided by the repetition factor (i.e., 2). The mapping from the first number of SRS ports (SRS ports 1000 - 1007) to the subset of the second number of symbols may be repeated for the time specified by the repetition factor (i.e., 2 times) on the second number of symbols. In some aspects, 1330 may be performed by the SRS mapping component 198.

[0132] In some aspects, to sequentially map a first number of SRS ports to a second number of OFDM symbols (at 1302), at 1332, the UE may map a subset of the first number of SRS ports to a single symbol, the subset being based on a repetition factor. For example, referring to ​ , when sequentially mapping eight SRS ports (SRS ports 1000 - 1007) to eight OFDM symbols (S1 - S8), assuming a repetition factor of 2, the UE may map a subset of the first number of SRS ports (SRS ports 1000 - 1001) to a single symbol (S1). The subset (i.e., 2 SRS ports) may be based on the repetition factor (i.e., 2). In some aspects, 1332 may be performed by the SRS mapping component 198.

[0133] In some aspects, at 1306, the UE may further associate a PUSCH transmission with the most recent transmission of the SRS resource indicated by the SRI, the most recent transmission not including a skipped transmission of at least one SRS port among the first number of SRS ports. For example, referring to ​ , at 1110, UE 1102 may associate a PUSCH transmission with the most recent transmission of the SRS resource indicated by the SRI, the most recent transmission not including a skipped transmission of at least one SRS port among the first number of SRS ports. Referring to ​ , the UE may associate a PUSCH transmission (on slot n + 1) with the transmission of SRS resource 1 at slot n - 4. SRS resource 1 is indicated by the SRI at slot n, and slot n - 4 does not include a skipped transmission of at least one SRS port among the eight SRS ports. In some aspects, 1306 may be performed by the SRS mapping component 198.

[0134] In some aspects, at 1308, the UE may determine whether to use a partial SRS transmission for PUSCH transmission based on one or more of SRS usage, codebook, or coherence. For example, referring to ​ , at 1112, UE 1102 may determine whether to use a partial SRS transmission for PUSCH transmission based on one or more of SRS usage, codebook, or coherence. Referring to ​ , the UE may determine whether to use a partial SRS transmission (e.g., the SRS transmission on ports 0 - 3 on slot n - 2) for PUSCH transmission based on whether SRS usage is for codebook - based 8Tx PUSCH and the coherence of the codebook / pre - decoder. In some aspects, 1308 may be performed by the SRS mapping component 198.

[0135] In some aspects, the SRS usage of the first number of SRS ports can be used for codebook - based PUSCH, and the first number of SRS ports can include a third number of SRS ports with coherent codebooks. And at 1310, the UE can discard all the first number of SRS ports in response to the discard of at least one SRS port among the first number of SRS ports communicating with a network entity. For example, referring to ​ , at 1114, the UE 1102 can discard all the first number of SRS ports in response to the discard of at least one SRS port among the first number of SRS ports communicating with a network entity (Base Station 1104). For example, as ​ shown, the UE can discard all eight SRS ports (SRS ports 0 - 7 in slot n - 2) in response to the discard of at least one SRS port among the eight SRS ports communicating with a network entity (i.e., the discard of SRS ports 4 - 7 in slot n - 2). In some aspects, 1310 can be performed by the SRS mapping component 198.

[0136] In some aspects, the usage of the first number of SRS ports can be used for codebook - based PUSCH, and the first number of SRS ports can include a fourth number of SRS ports with non - coherent codebooks. And at 1312, the UE can continue communicating with the network entity using the SRS ports that have not been discarded in response to the discard of at least one SRS port among the fourth number of SRS ports communicating with a network entity. For example, referring to ​ , at 1116, the UE 1102 can continue communicating with the network entity (Base Station 1104) using the SRS ports that have not been discarded in response to the discard of at least one SRS port among the fourth number of SRS ports communicating with a network entity (Base Station 1104). For example, referring to ​ , the UE can continue communicating with the network entity using the SRS ports that have not been discarded (e.g., SRS ports 0 - 3 and SRS ports 6 - 7 in slot n - 2) in response to the discard of at least one SRS port among the fourth number of SRS ports communicating with a network entity (e.g., the discard of SRS ports 4 - 5 in slot n - 2). In some aspects, 1312 can be performed by the SRS mapping component 198.

[0137] In some aspects, the SRS usage of the first number of SRS ports can be used for codebook - based PUSCH, and the codebook for the first number of SRS ports can be used for an antenna switching scheme. And at 1314, the UE can continue communicating with the network entity using the SRS ports that have not been discarded in response to the discard of at least one SRS port among the first number of SRS ports communicating with a network entity. For example, referring to ​, at 1118, the UE 1102 may continue communication with the network entity (base station 1104) using the SRS ports that have not been discarded in response to the discard of at least one SRS port among the first number of SRS ports communicating with the network entity. For example, referring to ​ , the UE may continue communication with the network entity using the SRS ports that have not been discarded (e.g., SRS ports 0-3 and SRS ports 6-7 in slot n-2) in response to the discard of at least one SRS port among the first number of SRS ports communicating with the network entity (e.g., the discard of SRS ports 4-5 in slot n-2). In some aspects, 1314 may be performed by the SRS mapping component 198.

[0138] ​ is a flowchart 1400 illustrating a method of wireless communication at a network entity according to various aspects of the present disclosure. The method may be performed by the network entity. The network entity may be ​ a base station or a component of a base station in an access network, or a core network component (e.g., base stations  102, 310, 1104; or ​ the network entity 1602 in a hardware implementation of ). The method implements or enhances 8Tx UL operation to support four and more layers per UE in the UL for the device. Thus, the aspects presented herein improve the efficiency of wireless communication.

[0139] As ​ shown, at 1402, the network entity may receive SRS from the first number of SRS ports of the UE that are sequentially mapped on the second number of OFDM symbols. The second number may be greater than one. The UE may be ​ the UE 104, 350, 1102 or the device 1604 in a hardware implementation of . ​ , ​ , ​ , ​ , ​ , ​ , ​ , ​ , ​ , ​ , ​ , ​ and ​ illustrate various aspects of the steps in conjunction with the flowchart 1400. For example, referring to ​ , at 1108, the network entity (base station 1104) may receive SRS from the first number of SRS ports of the UE 1102 that are sequentially mapped on the second number of OFDM symbols. In one example, referring to ​, eight SRS ports (SRS ports 1000 - 1007) can be mapped to four OFDM symbols (S1 - S4). In another example, refer to ​ , eight SRS ports (SRS ports 1000 - 1007) can be mapped to eight OFDM symbols (S1 - S8). In some aspects, 1402 can be performed by the SRS receiving component 199.

[0140] At 1404, the network entity can receive PUSCH transmissions based on the SRS. For example, refer to ​ , at 1120, the network entity (base station 1104) can receive PUSCH transmissions based on the SRS (received at 1108). In some aspects, 1404 can be performed by the SRS receiving component 199.

[0141] ​ is a flowchart 1500 illustrating a method of wireless communication at a network entity according to various aspects of the present disclosure. The method can be performed by the network entity. The network entity can be ​ a base station or a component of a base station in an access network, or a core network component (e.g., base stations 102, 310, 1104; or ​ the network entity 1602 in a hardware implementation of

[0142] As ​ shown, at 1502, the network entity can receive SRS from a first number of SRS ports of the UE that are sequentially mapped on a second number of OFDM symbols. The second number can be greater than one. The UE can be ​ the UE 104, 350, 1102 or the device 1604 in a hardware implementation of ​ , ​ , ​ , ​ , ​ , ​ , ​ , ​ , ​ , ​ , ​ , ​ and ​ illustrate various aspects of the steps in conjunction with flowchart 1500. For example, refer to ​ , at 1108, the network entity (base station 1104) can receive SRS from a first number of SRS ports of the UE 1102 that are sequentially mapped on a second number of OFDM symbols. In one example, refer to ​, eight SRS ports (SRS ports 1000 - 1007) can be mapped to four OFDM symbols (S1 - S4). In another example, refer to ​ , eight SRS ports (SRS ports 1000 - 1007) can be mapped to eight OFDM symbols (S1 - S8). In some aspects, 1502 can be performed by the SRS receiving component 199.

[0143] At 1504, the network entity can receive PUSCH transmissions based on the SRS. For example, refer to ​ , at 1120, the network entity (base station 1104) can receive PUSCH transmissions based on the SRS (received at 1108). In some aspects, 1504 can be performed by the SRS receiving component 199.

[0144] In some aspects, the SRS can be used for codebook - based PUSCH, and the first subset of SRS ports is coherent and the second subset of SRS ports can be coherent. The first subset of SRS ports can be non - coherent with the second subset of SRS ports. For example, refer to ​ , the first subset of SRS ports (SRS ports 1000 - 1003) can be coherent and the second subset of SRS ports (SRS ports 1004 - 1007) can be coherent. The first subset of SRS ports (SRS ports 1000 - 1003) can be non - coherent with the second subset of SRS ports (SRS ports 1004 - 1007).

[0145] In some aspects, at 1512, the first subset of SRS ports can be mapped to the first consecutive subset of OFDM symbols, and the second SRS ports can be mapped to the second consecutive subset of OFDM symbols. For example, refer to ​ , the first subset of SRS ports (SRS ports 1000 - 1003) can be mapped to the first consecutive subset of OFDM symbols (S1, S2), and the second subset of SRS ports (SRS ports 1004 - 1007) can be mapped to the second consecutive subset of OFDM symbols (S3, S4).

[0146] In some aspects, the first consecutive subset of OFDM symbols can be consecutive or non - consecutive with the second subset of OFDM symbols. For example, refer to ​ , the first consecutive subset of OFDM symbols can be OFDM symbol S1 and OFDM symbol S2, and the second consecutive subset of OFDM symbols can be OFDM symbol S3 and OFDM symbol S4. The first consecutive subset of OFDM symbols (S1 and S2) can be consecutive or non - consecutive with the second consecutive subset of OFDM symbols (S3 and S4).

[0147] In some aspects, at 1514, the first number of SRS ports that are coherent SRS port groups can be mapped to the second number of OFDM symbols within the same time slot or sub - slot. For example, referring to ​ , the first number of SRS ports that are coherent SRS port groups (SRS ports 1000 - 1003) can be mapped to the second number of OFDM symbols (S1 and S2) within the same time slot or sub - slot.

[0148] In some aspects, at 1516, non - coherent SRS ports can be mapped to the second number of OFDM symbols in different time slots or different sub - slots. For example, referring to ​ , SRS port 1002 and SRS port 1003 can be mapped to OFDM symbol S2, and SRS port 1004 and SRS port 1005 can be mapped to OFDM symbol S3. If SRS port 1002 and SRS port 1003 are non - coherent with SRS port 1004 and SRS port 1005, OFDM symbol S2 and OFDM symbol S3 can be in different time slots or sub - slots.

[0149] In some aspects, at 1518, the use of the first number of SRS ports can be used for codebook - based Physical Uplink Shared Channel (PUSCH), and the codebook for the first number of SRS ports can be used for an antenna switching scheme. At 1520, the first number of SRS ports can be sequentially mapped to the second number of OFDM symbols in consecutive or non - consecutive symbols based on the antenna switching scheme. For example, referring to ​ , eight SRS ports (SRS ports 1000 - 1007) can be mapped to two OFDM symbols (S1 and S2). If the use of eight SRS ports (SRS ports 1000 - 1007) is for codebook - based PUSCH and the codebook for eight SRS ports (SRS ports 1000 - 1007) is used for the antenna switching scheme, then the two OFDM symbols (S1 and S2) can be consecutive or non - consecutive symbols.

[0150] In some aspects, at 1518, the use of the first number of SRS ports can be used for codebook - based PUSCH, and the codebook for the first number of SRS ports can be used for an antenna switching scheme . At 1522, the first number of SRS ports can be sequentially mapped to the second number of OFDM symbols in the same time slot, the same sub - slot, different time slots or different sub - slots based on the antenna switching scheme. For example, referring to ​, eight SRS ports (SRS ports 1000 - 1007) can be mapped to two OFDM symbols (S1 and S2). If the use of the eight SRS ports (SRS ports 1000 - 1007) is for codebook - based PUSCH, and the codebook for the eight SRS ports (SRS ports 1000 - 1007) is used for an antenna switching scheme, the two OFDM symbols (S1 and S2) can be in the same time slot, the same sub - slot, different time slots, or different sub - slots.

[0151] In some aspects, at 1524, a first number of SRS ports can be each mapped to a subset of a second number of OFDM symbols, and the subset of the second number of OFDM symbols is based on the second number of OFDM symbols divided by a repetition factor. In some examples, the mapping from the first number of SRS ports to the subset of the second number of OFDM symbols can be repeated for a time specified by the repetition factor on the second number of OFDM symbols. For example, referring to ​ , when sequentially mapping a first number (i.e., 8) of SRS ports (SRS ports 1000 - 1007) to a second number (i.e., 8) of OFDM symbols (S1 - S8), assuming the repetition factor is 2, the first number (i.e., 8) of SRS ports (SRS ports 1000 - 1007) can first be mapped to a subset of the second number of symbols (i.e., symbols S1 - S4). The subset of the second number of symbols can be based on the second number of symbols (i.e., 8) divided by the repetition factor (i.e., 2). The mapping from the first number of SRS ports (SRS ports 1000 - 1007) to the subset of the second number of OFDM symbols can be repeated for a time specified by the repetition factor (e.g., 2 times) on the second number of OFDM symbols.

[0152] In some aspects, at 1526, a subset of a first number of SRS ports can be mapped to a single symbol, and the subset is based on the repetition factor. For example, referring to ​ , when sequentially mapping eight SRS ports (SRS ports 1000 - 1007) to eight OFDM symbols (S1 - S8), assuming the repetition factor is 2, a subset of the first number of SRS ports (SRS ports 1000 - 1001) can first be mapped to a single symbol (S1). The subset (i.e., 2 SRS ports) can be based on the repetition factor (i.e., 2).

[0153] In some aspects, PUSCH can be associated with the nearest SRS resource indicated by SRI, and the nearest SRS resource does not include skipping the transmission of at least one SRS port among the first number of SRS ports. For example, referring to ​, the PUSCH transmission (at time slot n+1) can be the associated SRS resource 1 transmission at time slot n-4. SRS resource 1 is indicated by the SRI at time slot n, and time slot n-4 is the most recent SRS resource 1 transmission that skips the transmission of at least one SRS port among the first number of SRS ports (SRS ports 0-7).

[0154] In some aspects, the association between the SRS and the PUSCH transmission can be based on whether at least a part of the SRS transmission has been discarded and on one or more of SRS usage, codebook, or coherence. For example, referring to ​ , the association between the SRS and the PUSCH transmission can be based on whether at least a part of the SRS transmission has been discarded (e.g., whether ports 4-7 have been discarded), and on whether the SRS usage is for codebook-based 8Tx PUSCH and the coherence of the codebook / precoder.

[0155] ​FIG. 1600 is a diagram illustrating an example of a hardware implementation for apparatus 1604. Apparatus 1604 may be a UE, a component of a UE, or may implement UE functionality. In some aspects, apparatus 1604 may include at least one cellular baseband processor (or processing circuitry) 1624 (also referred to as a modem) coupled to one or more transceivers 1622 (e.g., cellular RF transceivers). The cellular baseband processor (or processing circuitry) 1624 may include at least one on-chip memory (or memory circuitry) 1624'. In some aspects, apparatus 1604 may also include one or more subscriber identity module (SIM) cards 1620, and at least one application processor (or processing circuitry) 1606 coupled to a secure digital (SD) card 1608 and a screen 1610. The application processor (or processing circuitry) 1606 may include on-chip memory (or memory circuitry) 1606'. In some aspects, apparatus 1604 may also include a Bluetooth module 1612, a WLAN module 1614, a SPS module 1616 (e.g., GNSS module), one or more sensor modules 1618 (e.g., barometric pressure sensor / altimeter; motion sensors such as an inertial measurement unit (IMU), gyroscope, and / or accelerometer; light detection and ranging (LIDAR), radio assisted detection and ranging (RADAR), sound navigation and ranging (SONAR), magnetometer, audio, and / or other technologies for positioning), additional memory modules 1626, a power source 1630, and / or a camera 1632. The Bluetooth module 1612, the WLAN module 1614, and the SPS module 1616 may include on-chip transceivers (TRX) (or in some cases, only receivers (RX)). The Bluetooth module 1612, the WLAN module 1614, and the SPS module 1616 may include their own dedicated antennas and / or communicate using antenna 1680. The cellular baseband processor (or processing circuitry) 1624 communicates with UE 104 and / or with a RU associated with network entity 1602 via one or more antennas 1680 through transceiver 1622. The cellular baseband processor (or processing circuitry) 1624 and the application processor (or processing circuitry) 1606 may each separately include computer-readable media / memory (or memory circuitry) 1624', 1606'. The additional memory module 1626 may also be considered computer-readable media / memory (or memory circuitry). Each computer-readable media / memory (or memory circuitry) 1624', 1606', 1626 may be non-transitory. The cellular baseband processor (or processing circuitry) 1624 and the application processor (or processing circuitry) 1606 are each responsible for general processing, including execution of software stored on the computer-readable media / memory (or memory circuitry).When executed by the cellular baseband processor (or processing circuitry) 1624 / application processor (or processing circuitry) 1606, the software causes the cellular baseband processor (or processing circuitry) 1624 / application processor (or processing circuitry) 1606 to perform the various functions described above. The cellular baseband processor (or processing circuitry) 1624 and the application processor (or processing circuitry) 1606 are configured to perform the various functions described above at least in part based on information stored in the memory (or memory circuitry). That is, the cellular baseband processor (or processing circuitry) 1624 and the application processor (or processing circuitry) 1606 may be configured to perform a first subset of the various functions described above without the information stored in the memory, and may be configured to perform a second subset of the various functions described above based on the information stored in the memory. The computer-readable medium / memory (or memory circuitry) may also be used to store data manipulated by the cellular baseband processor (or processing circuitry) 1624 / application processor (or processing circuitry) 1606 when executing the software. The cellular baseband processor (or processing circuitry) 1624 / application processor (or processing circuitry) 1606 may be components of the UE 350 and may include 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 device 1604 may be at least one processor chip (modem and / or application) and include only the cellular baseband processor (or processing circuitry) 1624 and / or the application processor (or processing circuitry) 1606, while in another configuration, the device 1604 may be the entire UE (e.g., see. ​ of the UE 350) and include additional modules of the device 1604.

[0156] As discussed above, the component 198 may be configured to sequentially map a first number of SRS ports to a second number of OFDM symbols. The first number and the second number may each be greater than one. The component 198 may be further configured to transmit SRS from the first number of SRS ports on the second number of OFDM symbols based on the mapping. The component 198 may be further configured to perform any of the aspects described in the flowchart associated with ​ or ​ and / or by ​Any of the aspects performed by the UE 1102 in . Component 198 may be within the cellular baseband processor 1624, the application processor 1606, or both the cellular baseband processor 1624 and the application processor 1606. Component 198 may be one or more hardware components specifically configured to perform the stated process / algorithm, implemented by one or more processors configured to perform the stated process / algorithm, stored in a computer-readable medium for implementation by one or more processors, or some combination of the foregoing. As shown, the device 1604 may include multiple components configured for various functions. In one configuration, the device 1604 (and specifically, the cellular baseband processor 1624 and / or the application processor 1606) includes: a component for sequentially mapping a first number of SRS ports to a second number of OFDM symbols, the first number and the second number being each greater than one; and a component for sending SRS from the first number of SRS ports on the second number of OFDM symbols based on the mapping. The device 1604 may also include a component for performing a combined ​ and ​ Aspects of the flowcharts described and / or by ​ 1604 is a component 198 of the apparatus 1604 configured to perform the functions recited by the means. As described above, the apparatus 1604 may include the TX processor 368, the RX processor 356, and the controller / processor 359. Thus, 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.

[0157] ​FIG. 1700 is a diagram illustrating an example of a hardware implementation for network entity 1702. Network entity 1702 can be a BS, a component of a BS, or can implement BS functionality. Network entity 1702 can include at least one of CU 1710, DU 1730, or RU 1740. For example, depending on the layer functions handled by component 199, network entity 1702 can include CU 1710; both CU 1710 and DU 1730; each of CU 1710, DU 1730, and RU 1740; DU 1730; both DU 1730 and RU 1740; or RU 1740. CU 1710 can include at least one CU processor (or processing circuitry) 1712. CU processor (or processing circuitry) 1712 can include on-chip memory (or memory circuitry) 1712'. In some aspects, CU 1710 can also include additional memory modules 1714 and communication interface 1718. CU 1710 communicates with DU 1730 via an intermediate link, such as the F1 interface. DU 1730 can include at least one DU processor (or processing circuitry) 1732. DU processor (or processing circuitry) 1732 can include on-chip memory (or memory circuitry) 1732'. In some aspects, DU 1730 can also include additional memory modules 1734 and communication interface 1738. DU 1730 communicates with RU 1740 via a fronthaul link. RU 1740 can include at least one RU processor (or processing circuitry) 1742. RU processor (or processing circuitry) 1742 can include on-chip memory (or memory circuitry) 1742'. In some aspects, RU 1740 can also include additional memory modules 1744, one or more transceivers 1746, antenna 1780, and communication interface 1748. RU 1740 communicates with UE 104. On-chip memory (or memory circuitry) 1712', 1732', 1742', and additional memory modules 1714, 1734, 1744 can each be considered computer-readable media / memory (or memory circuitry). Each computer-readable media / memory (or memory circuitry) can be non-transitory. Each of processors (or processing circuitry) 1712, 1732, 1742 is responsible for general processing, including execution of software stored on the computer-readable media / memory (or memory circuitry). The software, when executed by the corresponding processor (or processing circuitry), causes the processor (or processing circuitry) to perform the various functions described above. The computer-readable media / memory (or memory circuitry) can also be used to store data manipulated by the processor (or processing circuitry) when executing the software.

[0158] As discussed above, component 199 may be configured to receive sounding reference signals (SRS) from a first number of SRS ports of a UE that are sequentially mapped onto a second number of orthogonal frequency division multiplexing (OFDM) symbols, where the second number is greater than one; and receive physical uplink shared channel (PUSCH) transmissions based on the SRS. Component 199 may be further configured to perform any of the aspects described in the flowchart associated with ​ or ​ and / or any of the aspects performed by the base station 1104 in ​ . Component 199 may be within one or more processors of one or more of the CU 1710, DU 1730, and RU 1740. Component 199 may be one or more hardware components specifically configured to perform the stated processes / algorithms, implemented by one or more processors configured to perform the stated processes / algorithms, stored in a computer-readable medium for implementation by one or more processors, or some combination of the above. Network entity 1702 may include various components configured for various functions. In one configuration, network entity 1702 includes: components for receiving SRS from a first number of SRS ports of a UE that are sequentially mapped onto a second number of OFDM symbols, where the second number is greater than one; and components for receiving PUSCH transmissions based on the SRS. Network entity 1702 may further include components for performing any of the aspects described in the flowchart associated with ​ and ​ and / or any of the aspects performed by the base station 1104 in ​ . The components may be component 199 of network entity 1702 configured to perform the functions recited by the components. As described above, network entity 1702 may include a TX processor 316, an RX processor 370, and a controller / processor 375. Thus, in one configuration, the components may be the TX processor 316, the RX processor 370, and / or the controller / processor 375 configured to perform the functions recited by the components.

[0159] The present disclosure provides a method for wireless communication at a UE. The method may include sequentially mapping a first number of SRS ports to a second number of OFDM symbols, where the first number and the second number are each greater than one; and transmitting SRS from the first number of SRS ports on the second number of OFDM symbols based on the mapping. The method enables or enhances 8Tx UL operation to support four or more layers per UE in the UL for the device. Thus, the aspects presented herein improve the efficiency of wireless communication.

[0160] It should be understood that the specific order or hierarchy of the boxes in the disclosed process / flowchart is merely illustrative of an example method. It should be understood that, based on design preferences, the specific order or hierarchy of the boxes in the process / flowchart can be rearranged. Further, some boxes can be combined or omitted. The appended method claims present the elements of the various boxes in a sample order, but are not limited to the specific order or hierarchy presented.

[0161] The foregoing 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 general principles defined herein may be applied to other aspects. Thus, the claims are not limited to the aspects described herein, but should be accorded the full scope consistent with the language of the claims. References to elements in the singular do not, unless specifically stated, mean "one and only one" but rather "one or more." Terms such as "if," "when," and "while" do not imply a direct temporal relationship or reaction. That is, these phrases, such as "when...," do not imply an immediate action in response to the occurrence of an action or during the occurrence of an action, but simply imply that if the condition is met, then the action will occur, without requiring a specific or immediate time limitation for the occurrence of the action. 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 having an advantage over other aspects. Unless specifically stated, 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 "any combination of A, B, C, or any of them," including any combination of A, B, and / or C, may include multiple As, multiple Bs, or multiple Cs. 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 "any combination of A, B, C, or any of them" may be only A, only B, only C, A and B, A and C, B and C, or A and B and C, where any such combination may contain one or more members of A, B, or C. A set should be construed as a collection of elements, where the number of elements is one or more. Thus, for a set of X, X will include one or more elements. When at least one processor is configured to perform a set of functions, the at least one processor is configured to perform the set of functions individually or in any combination. Thus, each processor in the at least one processor may be configured to perform a particular subset of the set of functions, where the subset is the complete set, a proper subset of the set, or an empty subset of the set. A processor may be referred to as a processor circuit. A memory / memory module may be referred to as a memory circuit. If a first device receives data from or sends data to a second device, the data may be received / sent directly between the first device and the second device, or indirectly between the first device and the second device through a collection of devices. A device configured to "output" data or "provide" data (such as a transmission, signal, or message) may, for example, send the data with a transceiver, or may convey the data to a device that sends the data.A device configured to “obtain” data (such as, a transmission, a signal, or a message) can receive the data, for example, with a transceiver, or can obtain the data from a device that received the data. Information stored in a memory includes instructions and / or data. All structural and functional equivalents of elements of the various aspects described throughout this disclosure that are known or will later be known to a person of ordinary skill in the art are expressly incorporated herein by reference and are covered by the claims. Additionally, nothing disclosed herein is intended to be dedicated to the public, whether or not such disclosure is expressly recited in the claims. The words “module,” “mechanism,” “element,” “device,” etc. do not substitute for the word “component.” Accordingly, no claim element will be construed as a means-plus-function unless the element is expressly recited using the phrase “means for...”

[0162] As used herein, the phrase “based on” should not be construed to refer to a closed set of information, one or more conditions, one or more factors, etc. Stated another way, the phrase “based on A” (where “A” can be information, a condition, a factor, etc.) should be construed as “at least based on A,” unless stated otherwise specifically.

[0163] The following aspects are merely illustrative and can be combined with other aspects or teachings described herein without limitation.

[0164] Aspect 1 is a method for wireless communication at a UE. The method can include sequentially mapping a first number of SRS ports to a second number of OFDM symbols, where the first number and the second number are each greater than one; and transmitting SRS from the first number of SRS ports on the second number of OFDM symbols based on the mapping.

[0165] Aspect 2 is the method according to aspect 1, where the SRS ports can be based on a codebook, a first subset of the SRS ports can be coherent and a second subset of the SRS ports can be coherent, and the first subset of the SRS ports can be non-coherent with the second subset of the SRS ports.

[0166] Aspect 3 is the method according to any one of aspects 1 to 2, where sequentially mapping the first number of SRS ports to the second number of OFDM symbols can include: mapping the first subset of the SRS ports to a first consecutive subset of the OFDM symbols; and mapping the second subset of the SRS ports to a second consecutive subset of the OFDM symbols.

[0167] Aspect 4 is the method according to aspect 3, where the first consecutive subset of the OFDM symbols can be consecutive or non-consecutive with the second consecutive subset of the OFDM symbols.

[0168] Aspect 5 is the method according to any one of Aspects 1 to 2, wherein the first number of SRS ports is a coherent SRS port group, and the first number of SRS ports can be mapped to the second number of OFDM symbols within the same time slot or sub - time slot.

[0169] Aspect 6 is the method according to any one of Aspects 1 to 2, wherein sequentially mapping the first number of SRS ports to the second number of OFDM symbols can further include: mapping a non - coherent SRS port group among the first number of SRS ports to different time slots or sub - time slots.

[0170] Aspect 7 is the method according to any one of Aspects 1 to 2, wherein the use of the first number of SRS ports can be used for codebook - based PUSCH, and the codebook for the first number of SRS ports can be used for an antenna switching scheme, wherein sequentially mapping the first number of SRS ports to the second number of OFDM symbols can include: mapping the first number of SRS ports to consecutive or non - consecutive symbols based on the antenna switching scheme.

[0171] Aspect 8 is the method according to any one of Aspects 1 to 2, wherein the use of the first number of SRS ports can be used for codebook - based PUSCH, and the codebook for the first number of SRS ports is used for an antenna switching scheme, wherein sequentially mapping the first number of SRS ports to the second number of OFDM symbols can include: mapping the first number of SRS ports to the same time slot, the same sub - time slot, different time slots or different sub - time slots based on the antenna switching scheme.

[0172] Aspect 9 is the method according to any one of Aspects 1 to 2, wherein the sequential mapping can include mapping the first number of SRS ports to a subset of the second number of symbols. The subset of the second number of symbols can be based on the second number of symbols divided by a repetition factor. The mapping from the first number of SRS ports to the subset of the second number of symbols can be repeated on the second number of symbols for a time specified by the repetition factor.

[0173] Aspect 10 is the method according to any one of Aspects 1 to 2, wherein the sequential mapping can include mapping a subset of the first number of SRS ports to a single symbol. The subset can be based on a repetition factor.

[0174] Aspect 11 is the method according to any one of Aspects 1 to 10, wherein the method can further include associating the PUSCH transmission with the most recent transmission of the SRS resource indicated by the SRI, and the most recent transmission does not include a skipped transmission of at least one SRS port among the first number of SRS ports.

[0175] Aspect 12 is the method according to any one of Aspects 1 to 10, wherein the method can further include determining whether to use a partial SRS transmission for PUSCH transmission based on one or more of SRS usage, codebook, or coherence.

[0176] Aspect 13 is the method according to Aspect 12, wherein the SRS usage of the first number of SRS ports can be used for codebook-based PUSCH, and the first number of SRS ports can include a third number of SRS ports having a coherent codebook, and the method can further include: in response to discarding at least one SRS port among the first number of SRS ports communicating with a network entity, discarding all the first number of SRS ports.

[0177] Aspect 14 is the method according to Aspect 12, wherein the usage of the first number of SRS ports can be used for codebook-based PUSCH, and the first number of SRS ports can include a fourth number of SRS ports having a non-coherent codebook, and the method can further include: in response to discarding at least one SRS port among the fourth number of SRS ports communicating with a network entity, continuing the communication with the network entity using the SRS ports that have not been discarded.

[0178] Aspect 15 is the method according to any one of Aspects 1 to 10, wherein the SRS usage of the first number of SRS ports can be used for codebook-based PUSCH, and the codebook for the first number of SRS ports can be used for an antenna switching scheme, and the method can further include: in response to discarding at least one SRS port among the first number of SRS ports communicating with a network entity, continuing the communication with the network entity using the SRS ports that have not been discarded.

[0179] Aspect 16 is a device for wireless communication at a UE, the device including: a processing system, the processing system including a processor circuit and a memory circuit, the memory circuit storing code and coupled to the processor circuit, the processing system being configured to cause the UE to perform the method according to one or more of Aspects 1 to 15.

[0180] Aspect 17 is an apparatus for wireless communication at a UE, the apparatus comprising: at least one memory; and at least one processor coupled to the at least one memory, and wherein the at least one processor is configured, alone or in any combination, to perform the method according to any one of Aspects 1 to 15.

[0181] Aspect 18 is an apparatus for wireless communication at a UE, the apparatus comprising components for performing each step of the method according to any one of Aspects 1 to 15.

[0182] Aspect 19 is the apparatus according to any one of Aspects 16 to 18, the apparatus further comprising a transceiver configured to receive or transmit in association with the method according to any one of Aspects 1 to 15.

[0183] Aspect 20 is a computer-readable medium (e.g., a non-transitory computer-readable medium) storing computer-executable code at a UE, the code causing the at least one processor to perform, alone or in any combination, the method according to any one of Aspects 1 to 15 when executed by the at least one processor.

[0184] Aspect 21 is a method for wireless communication at a network entity. The method can include receiving SRS from a first number of SRS ports of a UE and sequentially mapped on a second number of OFDM symbols, where the second number is greater than one; and receiving a PUSCH transmission based on the SRS.

[0185] Aspect 22 is the method according to Aspect 21, wherein the SRS can be used for codebook-based PUSCH, and a first subset of the SRS ports is coherent and a second subset of the SRS ports is coherent. The first subset of SRS ports can be non-coherent with the second subset of SRS ports.

[0186] Aspect 23 is the method according to Aspect 22, wherein the first subset of SRS ports can be mapped to a first consecutive subset of the OFDM symbols, and a second SRS port can be mapped to a second consecutive subset of the OFDM symbols. [[ID=,20]]

[0187] Aspect 24 is the method according to Aspect 23, wherein the first consecutive subset of the OFDM symbols can be consecutive or non-consecutive with the second subset of the OFDM symbols.

[0188] Aspect 25 is the method according to Aspect 21, wherein based on the first number of SRS ports being a coherent SRS port group, the first number of SRS ports can be mapped to the second number of OFDM symbols within the same time slot or sub-time slot.

[0189] Aspect 26 is the method according to any one of Aspects 21 to 25, wherein the non-coherent SRS ports can be mapped to the second number of OFDM symbols in different time slots or different sub-time slots.

[0190] Aspect 27 is the method according to any one of Aspects 21 to 26, wherein the use of the first number of SRS ports can be used for codebook-based PUSCH, and the codebook for the first number of SRS ports can be used for an antenna switching scheme. The first number of SRS ports can be sequentially mapped to the second number of OFDM symbols in consecutive or discontinuous symbols based on the antenna switching scheme.

[0191] Aspect 28 is the method according to any one of Aspects 21 to 26, wherein the use of the first number of SRS ports can be used for codebook-based PUSCH, and the codebook for the first number of SRS ports can be used for an antenna switching scheme. The first number of SRS ports can be sequentially mapped to the second number of OFDM symbols in the same time slot, the same sub-time slot, different time slots or different sub-time slots based on the antenna switching scheme.

[0192] Aspect 29 is the method according to any one of Aspects 21 to 28, wherein the first number of SRS ports can be each mapped to a subset of the second number of symbols. The subset of the second number of symbols can be based on dividing the second number of symbols by a repetition factor. The mapping from the first number of SRS ports to the subset of the second number of symbols can be repeated for the time specified by the repetition factor over the second number of symbols.

[0193] Aspect 30 is the method according to any one of Aspects 21 to 28, wherein a subset of the first number of SRS ports can be mapped to a single symbol, and the subset can be based on a repetition factor.

[0194] Aspect 31 is the method according to any one of Aspects 21 to 28, wherein the PUSCH can be associated with the nearest SRS resource indicated by the SRI, and the nearest SRS resource does not include skipping the transmission of at least one SRS port among the first number of SRS ports.

[0195] Aspect 32 is the method according to any one of Aspects 21 to 28, wherein the association between the SRS and the PUSCH transmission can be based on whether at least a part of the SRS transmission has been discarded and based on one or more of SRS usage, codebook or coherence.

[0196] Aspect 33 is a device for wireless communication at a network entity, the device comprising: a processing system including a processor circuit and a memory circuit, the memory circuit storing code and being coupled to the processor circuit, the processing system being configured to cause the network entity to perform the method according to one or more of aspects 21 to 32.

[0197] Aspect 34 is a device for wireless communication at a network entity, the device comprising: at least one memory; and at least one processor, the at least one processor being coupled to the at least one memory, and wherein the at least one processor is configured, alone or in any combination, to perform the method according to any one of aspects 21 to 32.

[0198] Aspect 35 is a device for wireless communication at a network entity, the device comprising components for performing each step of the method according to any one of aspects 21 to 32.

[0199] Aspect 36 is the device according to any one of aspects 33 to 35, the device further comprising a transceiver configured to receive or transmit in association with the method according to any one of aspects 21 to 32.

[0200] Aspect 37 is a computer-readable medium (e.g., a non-transitory computer-readable medium) storing computer-executable code at a network entity, the code causing the at least one processor to perform, alone or in any combination, the method according to any one of aspects 21 to 32 when executed by the at least one processor.

Claims

1. An apparatus for wireless communication at a user equipment (UE), the apparatus comprising: at least one memory; and at least one processor coupled to the at least one memory and, based at least in part on information stored in the at least one memory, configured, alone or in any combination, to cause the UE to: sequentially mapping a first number of sounding reference signal (SRS) ports to a second number of orthogonal frequency division multiplexing (OFDM) symbols, the first number and the second number each being greater than one; and The SRS is transmitted from the first number of SRS ports on the second number of OFDM symbols.

2. The apparatus of claim 1 , further comprising a transceiver coupled to the at least one processor, wherein, to transmit the SRS, the at least one processor is configured, alone or in any combination, to cause the UE to transmit the SRS via the transceiver, and wherein the SRS ports are based on a codebook, wherein a first subset of the SRS ports is coherent and a second subset of the SRS ports is coherent, and the first subset of the SRS ports is incoherent from the second subset of the SRS ports.

3. The apparatus of claim 2 , wherein, to sequentially map the first number of SRS ports to the second number of OFDM symbols, the at least one processor is configured, alone or in any combination, to cause the UE to: mapping the first subset of the SRS ports to a first contiguous subset of the OFDM symbols; and The second subset of the SRS ports is mapped to a second contiguous subset of the OFDM symbols. 4 . The apparatus according to claim 3 , wherein the first contiguous subset of the OFDM symbols and the second contiguous subset of the OFDM symbols are contiguous or discontinuous. 5 . The apparatus of claim 2 , wherein the first number of SRS ports are mapped to the second number of OFDM symbols within a same slot or subslot based on the first number of SRS ports being a coherent SRS port group.

6. The apparatus of claim 1 , wherein to sequentially map the first number of SRS ports to the second number of OFDM symbols, the at least one processor, alone or in any combination, is further configured to cause the UE to: Mapping non-coherent SRS port groups among the first number of SRS ports to different time slots or sub-time slots.

7. The apparatus of claim 1 , wherein use of the first number of SRS ports is for a codebook-based physical uplink shared channel (PUSCH), and the codebook for the first number of SRS ports is used for an antenna switching scheme, wherein to sequentially map the first number of SRS ports to the second number of OFDM symbols, the at least one processor is configured, alone or in any combination, to cause the UE to: The first number of SRS ports are mapped to consecutive or non-consecutive symbols based on the antenna switching scheme.

8. The apparatus of claim 1 , wherein the use of the first number of SRS ports is for a codebook-based physical uplink shared channel (PUSCH), and the codebook for the first number of SRS ports is used for an antenna switching scheme, wherein to sequentially map the first number of SRS ports to the second number of OFDM symbols, the at least one processor is configured, alone or in any combination, to cause the UE to: The first number of SRS ports are mapped to the same time slot, the same sub-time slot, different time slots, or different sub-time slots based on the antenna switching scheme.

9. The apparatus of claim 1 , wherein to sequentially map the first number of SRS ports to the second number of OFDM symbols, the at least one processor is configured, alone or in any combination, to cause the UE to: Mapping the first number of SRS ports to a subset of the second number of symbols, the subset of the second number of symbols being based on the second number of symbols divided by a repetition factor, wherein the mapping from the first number of SRS ports to the subset of the second number of symbols is repeated over the second number of symbols for a time specified by the repetition factor.

10. The apparatus of claim 1 , wherein to sequentially map the first number of SRS ports to the second number of OFDM symbols, the at least one processor is configured, alone or in any combination, to cause the UE to: A subset of the first number of SRS ports is mapped to a single symbol, the subset being based on a repetition factor.

11. The apparatus of claim 1 , wherein the at least one processor, alone or in any combination, is further configured to cause the UE to: A physical uplink shared channel (PUSCH) transmission is associated with a most recent transmission of SRS resources indicated by an SRS resource indicator (SRI), the most recent transmission not including a skipped transmission of at least one SRS port of the first number of SRS ports.

12. The apparatus of claim 1 , wherein the at least one processor, alone or in any combination, is further configured to cause the UE to: Whether to use a portion of the SRS transmission for a physical uplink shared channel (PUSCH) transmission is determined based on one or more of SRS usage, codebook, or coherence.

13. The apparatus of claim 12 , wherein the SRS usage of the first number of SRS ports is for a codebook-based PUSCH, and the first number of SRS ports includes a third number of SRS ports with a coherent codebook, and the at least one processor, alone or in any combination, is further configured to cause the UE to: In response to dropping of at least one of the first number of SRS ports in communication with a network entity, dropping all of the first number of SRS ports.

14. The apparatus of claim 12 , wherein the use of the first number of SRS ports is for a codebook-based physical uplink shared channel (PUSCH), and the first number of SRS ports includes a fourth number of SRS ports having a non-coherent codebook, and the at least one processor, alone or in any combination, is further configured to cause the UE to: In response to dropping of at least one SRS port of the fourth number of SRS ports for communicating with a network entity, continuing the communication with the network entity using the SRS port that has not been dropped.

15. The apparatus of claim 1 , wherein SRS usage of the first number of SRS ports is for a codebook-based physical uplink shared channel (PUSCH), and the codebook for the first number of SRS ports is used for an antenna switching scheme, and wherein the at least one processor is further configured, alone or in any combination, to cause the UE to: In response to dropping of at least one SRS port of the first number of SRS ports for communicating with a network entity, continuing the communication with the network entity using the SRS port that has not been dropped.

16. An apparatus for wireless communication at a network entity, the apparatus comprising: at least one memory; and at least one processor coupled to the at least one memory and, based at least in part on information stored in the at least one memory, configured, alone or in any combination, to cause the network entity to: receiving a first number of sounding reference signal (SRS) ports of a user equipment (UE) and sequentially mapped onto a second number of orthogonal frequency division multiplexing (OFDM) symbols, wherein the second number is greater than one; and A physical uplink shared channel (PUSCH) transmission is received based on the SRS.

17. The apparatus of claim 16 , further comprising a transceiver coupled to the at least one processor, wherein, to receive the SRS, the at least one processor is configured, alone or in any combination, to cause the network entity to receive the SRS via the transceiver, and wherein the SRS is used for a codebook-based PUSCH, and a first subset of the SRS ports is coherent and a second subset of the SRS ports is coherent, and the first subset of the SRS ports is incoherent from the second subset of the SRS ports.

18. The apparatus of claim 17, wherein the first subset of the SRS ports is mapped to a first contiguous subset of the OFDM symbols, and the second subset of the SRS ports is mapped to a second contiguous subset of the OFDM symbols.

19. The apparatus of claim 18, wherein the first contiguous subset of the OFDM symbols and the second subset of the OFDM symbols are contiguous or non-contiguous.

20. The apparatus of claim 16, wherein the first number of SRS ports are mapped to the second number of OFDM symbols within a same slot or subslot based on the first number of SRS ports being a coherent SRS port group.

21. The apparatus of claim 16, wherein non-coherent SRS ports are mapped to the second number of OFDM symbols in different slots or different subslots.

22. The apparatus of claim 16 , wherein the use of the first number of SRS ports is for a codebook-based physical uplink shared channel (PUSCH), and the codebook for the first number of SRS ports is used for an antenna switching scheme, wherein the first number of SRS ports are sequentially mapped to the second number of OFDM symbols in consecutive or non-consecutive symbols based on the antenna switching scheme.

23. The apparatus of claim 16 , wherein the use of the first number of SRS ports is for a codebook-based physical uplink shared channel (PUSCH), and the codebook for the first number of SRS ports is used for an antenna switching scheme, wherein the first number of SRS ports are sequentially mapped to the second number of OFDM symbols in the same slot, the same subslot, different slots, or different subslots based on the antenna switching scheme.

24. The apparatus of claim 16 , wherein the first number of SRS ports are each mapped to a subset of the second number of OFDM symbols, the subset of the second number of OFDM symbols being based on the second number of OFDM symbols divided by a repetition factor, wherein the mapping from the first number of SRS ports to the subset of the second number of OFDM symbols is repeated over the second number of OFDM symbols for a time specified by the repetition factor.

25. The apparatus of claim 16, wherein a subset of the first number of SRS ports is mapped to a single symbol, and the subset is based on a repetition factor.

26. The apparatus of claim 16, wherein the PUSCH transmission is associated with a most recent SRS resource indicated by an SRS resource indicator (SRI), the most recent SRS resource excluding skipped transmission of at least one SRS port of the first number of SRS ports.

27. The apparatus of claim 16, wherein the association of the SRS with the PUSCH transmission is based on whether at least a portion of an SRS transmission has been dropped and based on one or more of SRS usage, codebook, or coherence.

28. A method of wireless communication at a user equipment (UE), the method comprising: sequentially mapping a first number of sounding reference signal (SRS) ports to a second number of orthogonal frequency division multiplexing (OFDM) symbols, the first number and the second number each being greater than one; and SRS is transmitted from the first number of SRS ports on the second number of OFDM symbols based on the mapping.

29. The method of claim 28, wherein the SRS ports are based on a codebook, wherein a first subset of the SRS ports is coherent and a second subset of the SRS ports is coherent, the first subset of the SRS ports being incoherent with the second subset of the SRS ports.

30. A method of wireless communication at a network entity, the method comprising: receiving a first number of sounding reference signal (SRS) ports of a user equipment (UE) and sequentially mapped onto a second number of orthogonal frequency division multiplexing (OFDM) symbols, wherein the second number is greater than one; and A physical uplink shared channel (PUSCH) transmission is received based on the SRS.

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