Improved link robustness and spectral efficiency with cyclic prefix shortening coupled to transmission equalization

Abstract

The apparatus may be a wireless device configured to receive an indication of a reduced CP length associated with at least one DL transmission, receive the at least one DL transmission using the reduced CP length, and transmit a response to the at least one DL transmission. In certain aspects, the apparatus may be a network device configured to transmit an indication of a reduced CP length associated with at least one DL transmission and transmit the at least one DL transmission using the reduced CP length.

Description

Qualcomm Ref. No. 2500350WO 1 / 63IMPROVED LINK ROBUSTNESS AND SPECTRAL EFFICIENCY WITH CYCLIC PREFIX SHORTENING COUPLED TO TRANSMISSION EQUALIZATIONCROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of Israel Patent Application No. 319559, entitled “IMPROVED LINK ROBUSTNESS AND SPECTRAL EFFICIENCY WITH CYCLIC PREFIX SHORTENING COUPLED TO TRANSMISSION EQUALIZATION” and filed on March 12, 2025, which is expressly incorporated by reference herein in its entirety.TECHNICAL FIELD

[0002] The present disclosure relates generally to communication systems, and more particularly, to power saving at a user equipment (UE) associated with a transmissionside equalization for wireless communication.INTRODUCTION

[0003] Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasts. Typical wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources. Examples of such multiple-access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single-carrier frequency division multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems.

[0004] These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate on a municipal, national, regional, and even global level. An example telecommunication standard is 5G New Radio (NR). 5G NR is part of a continuous mobile broadband evolution promulgated by Third Generation Partnership Project (3 GPP) to meet new requirements associated with latency, reliability, security,129025-2594WO01Qualcomm Ref. No. 2500350WO 2 / 63scalability (e.g., with Internet of Things (IoT)), and other requirements. 5G NR includes services associated with enhanced mobile broadband (eMBB), massive machine type communications (mMTC), and ultra-reliable low latency communications (URLLC). Some aspects of 5G NR may be based on the 4G Long Term Evolution (LTE) standard. There exists a need for further improvements in 5G NR technology. These improvements may also be applicable to other multi-access technologies and the telecommunication standards that employ these technologies.BRIEF SUMMARY

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

[0006] In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be a receiving wireless device such as a UE configured to receive an indication of a reduced cyclic prefix (CP) length associated with at least one downlink (DL) transmission, receive the at least one DL transmission using the reduced CP length, and transmit a response to the at least one DL transmission.

[0007] In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be a transmitting wireless device or network device such as a base station configured to transmit an indication of a reduced CP length associated with at least one DL transmission and transmit the at least one DL transmission using the reduced CP length.

[0008] To the accomplishment of the foregoing and related ends, the one or more aspects may include the features hereinafter fully described and particularly pointed out in the claims. The following description and the drawings set forth in detail certain illustrative features of the one or more aspects. These features are indicative, however, of but a few of the various ways in which the principles of various aspects may be employed.129025-2594WO01Qualcomm Ref. No. 2500350WO 3 / 63BRIEF DESCRIPTION OF THE DRAWINGS

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

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

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

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

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

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

[0015] FIG. 4 is a diagram illustrating a channel support associated with a channel.

[0016] FIG. 5 is a diagram illustrating an OFDM transmitter and an OFDM receiver associated with a transmit-side equalization in accordance with some aspects of the disclosure.

[0017] FIG. 6A is a diagram illustrating an example use of resources saved by CP shortening in a first set of OFDM symbols.

[0018] FIG. 6B is a diagram illustrating an example use of resources saved by CP shortening in a first set of OFDM symbols.

[0019] FIG. 7 is a call flow diagram illustrating a method of wireless communication in accordance with some aspects of the disclosure.

[0020] FIG. 8 is a flowchart of a method of wireless communication.

[0021] FIG. 9 is a flowchart of a method of wireless communication.

[0022] FIG. 10 is a flowchart of a method of wireless communication.

[0023] FIG. 11 is a diagram illustrating an example of a hardware implementation for an example apparatus and / or network entity.

[0024] FIG. 12 is a diagram illustrating an example of a hardware implementation for an example network entity.129025-2594WO01Qualcomm Ref. No. 2500350WO 4 / 63DETAILED DESCRIPTION

[0025] In some aspects of wireless communication reducing power consumption at UEs, and specifically at reduced capability (or RedCap) UEs. One approach addressing power saving is shifting more and more processing from the UE side to the base station side. A significant source of power consumption that may be shifted to the base station is channel equalization for a DL transmission, e.g., a receive-side equalization (or Rx equalization) may be replaced with a transmission-side equalization (or Tx equalization).

[0026] To the extent that channel equalization can be shifted from the UE to a transmitting device such as a base station, a complexity of processing a received DL transmission may be reduced. In some aspects, by shifting the equalization from the UE to the transmitting device, the UE may also save power associated with a demodulation of the received DL transmission prior to a decoding process. In practical terms, this may allow the receiver (e.g., the UE) to operate in a lower-power mode, which may be particularly beneficial for low power constrained systems, where power efficiency is a higher priority.

[0027] Tx equalization may be specifically suitable for DL transmission, as the Tx side (e.g., a base station) may have more advanced and / or a greater computation capability than a receiving device (e.g., a UE or a RedCap UE). The use of Tx equalization, in some aspects, may extend a battery lifetime of a portable device, enhances the overall system efficiency, and may also mitigate, reduce, or improve, a power dissipation budget (or thermal budget) relating to how fast the receiving device generates and / or dissipates thermal energy. Tx equalization is expected to attract more popularity as greater numbers of lower-power devices (such as extended reality (XR) glasses, virtual reality (VR) and augmented reality (AR) devices, etc.) are introduced within a network.

[0028] In some aspects, a cyclic prefix (CP) may be appended to a DL message before transmission. A CP may allow a receiving device to account for dispersion experienced during transmission over a channel. A channel support (e.g., a measure of a dispersion associated with the channel) may determine, or be associated with, a minimum length of a CP that may be used to compensate for the channel support and / or dispersion. For example, the more dispersive the channel is, the longer the minimum CP length becomes. While the minimum length of the CP, i.e., the minimum129025-2594WO01Qualcomm Ref. No. 2500350WO 5 / 63number of samples added at the beginning of each time dispersive orthogonal frequency division multiplexing (OFDM) symbol, depends on the channel length (or the channel support), in practice, regardless of the channel’s support, the CP length may be a constant (e.g., ~7% of the symbol duration and / or a transmitted signal). Based on the constant CP length (e.g., which may have a fixed length such as a defined length in a telecommunication standard), the overhead associated with the CP is fixed.

[0029] Various aspects relate generally to shortening the default CP length (e.g., a default length defined in a standard) when implementing and / or using the Tx equalization such that the overall channel that the signal experiences has a much shorter support (e.g., is associated with less dispersion in time). Some aspects more specifically relate to a network configuring and / or indicating a shortened CP as a result of Tx equalization (e.g., implementing a channel inversion based on channel knowledge at the transmitter). Some aspects relate to different implementations and uses of the portion of a symbol associated with a standard CP length not used for transmitting the CP based on a shortened CP. In some examples, a wireless device may be configured to receive an indication of a reduced CP length associated with at least one DL transmission, receive the at least one DL transmission using the reduced CP length, and transmit a response to the at least one DL transmission. In some aspects, a network device may be configured to transmit an indication of a reduced CP length associated with at least one DL transmission and transmit the at least one DL transmission using the reduced CP length.

[0030] Particular aspects of the subject matter described in this disclosure can be implemented to realize one or more of the following potential advantages. In some examples, by indicating and / or using a shortened CP length, the described techniques can be used to improve wireless communications, improve spectral efficiency, and / or introduce additional functions (e.g., associated with using the remaining CP resources to increase throughput, add a time domain pilot, enable a listening mode, etc.).

[0031] The detailed description set forth below in connection with the drawings describes various configurations and does not represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of various concepts. However, these concepts may be practiced without these specific details. In some129025-2594WO01Qualcomm Ref. No. 2500350WO 6 / 63instances, well known structures and components are shown in block diagram form in order to avoid obscuring such concepts.

[0032] Several aspects of telecommunication systems are presented with reference to various apparatus and methods. These apparatus and methods are described in the following detailed description and illustrated in the accompanying drawings by various blocks, components, circuits, processes, algorithms, etc. (collectively referred to as “elements”). These elements may be implemented using electronic hardware, computer software, or any combination thereof. Whether such elements are implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system.

[0033] By way of example, an element, or any portion of an element, or any combination of elements may be implemented as a “processing system” that includes one or more processors. When multiple processors are implemented, the multiple processors may perform the functions individually or in combination. Examples of processors include microprocessors, microcontrollers, graphics processing units (GPUs), central processing units (CPUs), application processors, digital signal processors (DSPs), reduced instruction set computing (RISC) processors, systems on a chip (SoC), baseband processors, field programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functionality described throughout this disclosure. One or more processors in the processing system may execute software. Software, whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise, shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software components, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, or any combination thereof.

[0034] Accordingly, in one or more example aspects, implementations, and / or use cases, the functions described may be implemented in hardware, software, or any combination thereof. If implemented in software, the functions may be stored on or encoded as one or more instructions or code on a computer-readable medium. Computer-readable media includes computer storage media. Storage media may be any available media that can be accessed by a computer. By way of example, such computer-readable129025-2594WO01Qualcomm Ref. No. 2500350WO 7 / 63media can include a random-access memory (RAM), a read-only memory (ROM), an electrically erasable programmable ROM (EEPROM), optical disk storage, magnetic disk storage, other magnetic storage devices, combinations of the types of computer- readable media, or any other medium that can be used to store computer executable code in the form of instructions or data structures that can be accessed by a computer.

[0035] While aspects, implementations, and / or use cases are described in this application by illustration to some examples, additional or different aspects, implementations and / or use cases may come about in many different arrangements and scenarios. Aspects, implementations, and / or use cases described herein may be implemented across many differing platform types, devices, systems, shapes, sizes, and packaging arrangements. For example, aspects, implementations, and / or use cases may come about via integrated chip implementations and other non-module-component based devices (e.g., end-user devices, vehicles, communication devices, computing devices, industrial equipment, retail / purchasing devices, medical devices, artificial intelligence (Al)-enabled devices, etc.). While some examples may or may not be specifically directed to use cases or applications, a wide assortment of applicability of described examples may occur. Aspects, implementations, and / or use cases may range a spectrum from chip-level or modular components to non-modular, non-chip- level implementations and further to aggregate, distributed, or original equipment manufacturer (OEM) devices or systems incorporating one or more techniques herein. In some practical settings, devices incorporating described aspects and features may also include additional components and features for implementation and practice of claimed and described aspect. For example, transmission and reception of wireless signals necessarily includes a number of components for analog and digital purposes (e.g., hardware components including antenna, RF-chains, power amplifiers, modulators, buffer, processor(s), interleaver, adders / summers, etc.). Techniques described herein may be practiced in a wide variety of devices, chip-level components, systems, distributed arrangements, aggregated or disaggregated components, end-user devices, etc. of varying sizes, shapes, and constitution.

[0036] Deployment of communication systems, such as 5GNR systems, may be arranged in multiple manners with various components or constituent parts. In a 5GNR system, or network, a network node, a network entity, a mobility element of a network, a radio access network (RAN) node, a core network node, a network element, or a network129025-2594WO01Qualcomm Ref. No. 2500350WO 8 / 63equipment, such as a base station (BS), or one or more units (or one or more components) performing base station functionality, may be implemented in an aggregated or disaggregated architecture. For example, a BS (such as a Node B (NB), evolved NB (eNB), NR BS, 5G NB, access point (AP), a transmission reception point (TRP), or a cell, etc.) may be implemented as an aggregated base station (also known as a standalone BS or a monolithic BS) or a disaggregated base station.

[0037] An aggregated base station may be configured to utilize a radio protocol stack that is physically or logically integrated within a single RAN node. A disaggregated base station may be configured to utilize a protocol stack that is physically or logically distributed among two or more units (such as one or more central or centralized units (CUs), one or more distributed units (DUs), or one or more radio units (RUs)). In some aspects, a CU may be implemented within a RAN node, and one or more DUs may be co-located with the CU, or alternatively, may be geographically or virtually distributed throughout one or multiple other RAN nodes. The DUs may be implemented to communicate with one or more RUs. Each of the CU, DU and RU can be implemented as virtual units, i.e., a virtual central unit (VCU), a virtual distributed unit (VDU), or a virtual radio unit (VRU).

[0038] Base station operation or network design may consider aggregation characteristics of base station functionality. For example, disaggregated base stations may be utilized in an integrated access backhaul (IAB) network, an open radio access network (O- RAN (such as the network configuration sponsored by the O-RAN Alliance)), or a virtualized radio access network (vRAN, also known as a cloud radio access network (C-RAN)). Disaggregation may include distributing functionality across two or more units at various physical locations, as well as distributing functionality for at least one unit virtually, which can enable flexibility in network design. The various units of the disaggregated base station, or disaggregated RAN architecture, can be configured for wired or wireless communication with at least one other unit.

[0039] FIG. 1 is a diagram 100 illustrating an example of a wireless communications system and an access network. The illustrated wireless communications system includes a disaggregated base station architecture. The disaggregated base station architecture may include one or more CUs 110 that can communicate directly with a core network 120 via a backhaul link, or indirectly with the core network 120 through one or more disaggregated base station units (such as a Near-Real Time (Near-RT) RAN129025-2594WO01Qualcomm Ref. No. 2500350WO 9 / 63Intelligent Controller (RIC) 125 via an E2 link, or a Non-Real Time (Non-RT) RIC 115 associated with a Service Management and Orchestration (SMO) Framework 105, or both). A CU 110 may communicate with one or more DUs 130 via respective midhaul links, such as an Fl interface. The DUs 130 may communicate with one or more RUs 140 via respective fronthaul links. The RUs 140 may communicate with respective UEs 104 via one or more radio frequency (RF) access links. In some implementations, the UE 104 may be simultaneously served by multiple RUs 140.

[0040] Each of the units, i.e., the CUs 110, the DUs 130, the RUs 140, as well as the Near- RT RICs 125, the Non-RT RICs 115, and the SMO Framework 105, may include one or more interfaces or be coupled to one or more interfaces configured to receive or to transmit signals, data, or information (collectively, signals) via a wired or wireless transmission medium. Each of the units, or an associated processor or controller providing instructions to the communication interfaces of the units, can be configured to communicate with one or more of the other units via the transmission medium. For example, the units can include a wired interface configured to receive or to transmit signals over a wired transmission medium to one or more of the other units. Additionally, the units can include a wireless interface, which may include a receiver, a transmitter, or a transceiver (such as an RF transceiver), configured to receive or to transmit signals, or both, over a wireless transmission medium to one or more of the other units.

[0041] In some aspects, the CU 110 may host one or more higher layer control functions.Such control functions can include radio resource control (RRC), packet data convergence protocol (PDCP), service data adaptation protocol (SDAP), or the like. Each control function can be implemented with an interface configured to communicate signals with other control functions hosted by the CU 110. The CU 110 may be configured to handle user plane functionality (i.e., Central Unit - User Plane (CU-UP)), control plane functionality (i.e., Central Unit - Control Plane (CU-CP)), or a combination thereof. In some implementations, the CU 110 can be logically split into one or more CU-UP units and one or more CU-CP units. The CU-UP unit can communicate bidirectionally with the CU-CP unit via an interface, such as an El interface when implemented in an O-RAN configuration. The CU 110 can be implemented to communicate with the DU 130, as necessary, for network control and signaling.129025-2594WO01Qualcomm Ref. No. 2500350WO 10 / 63

[0042] The DU 130 may correspond to a logical unit that includes one or more base station functions to control the operation of one or more RUs 140. In some aspects, the DU 130 may host one or more of a radio link control (RLC) layer, a medium access control (MAC) layer, and one or more high physical (PHY) layers (such as modules for forward error correction (FEC) encoding and decoding, scrambling, modulation, demodulation, or the like) depending, at least in part, on a functional split, such as those defined by 3 GPP. In some aspects, the DU 130 may further host one or more low PHY layers. Each layer (or module) can be implemented with an interface configured to communicate signals with other layers (and modules) hosted by the DU 130, or with the control functions hosted by the CU 110.

[0043] Lower-layer functionality can be implemented by one or more RUs 140. In some deployments, an RU 140, controlled by a DU 130, may correspond to a logical node that hosts RF processing functions, or low-PHY layer functions (such as performing fast Fourier transform (FFT), inverse FFT (iFFT), digital beamforming, physical random access channel (PRACH) extraction and filtering, or the like), or both, based at least in part on the functional split, such as a lower layer functional split. In such an architecture, the RU(s) 140 can be implemented to handle over the air (OTA) communication with one or more UEs 104. In some implementations, real-time and non-real-time aspects of control and user plane communication with the RU(s) 140 can be controlled by the corresponding DU 130. In some scenarios, this configuration can enable the DU(s) 130 and the CU 110 to be implemented in a cloud-based RAN architecture, such as a vRAN architecture.

[0044] The SMO Framework 105 may be configured to support RAN deployment and provisioning of non-virtualized and virtualized network elements. For non-virtualized network elements, the SMO Framework 105 may be configured to support the deployment of dedicated physical resources for RAN coverage requirements that may be managed via an operations and maintenance interface (such as an 01 interface). For virtualized network elements, the SMO Framework 105 may be configured to interact with a cloud computing platform (such as an open cloud (O-Cloud) 190) to perform network element life cycle management (such as to instantiate virtualized network elements) via a cloud computing platform interface (such as an 02 interface). Such virtualized network elements can include, but are not limited to, CUs 110, DUs 130, RUs 140 and Near-RT RICs 125. In some implementations, the SMO Framework129025-2594WO01Qualcomm Ref. No. 2500350WO 11 / 63105 can communicate with a hardware aspect of a 4G RAN, such as an open eNB (O- eNB) 111, via an 01 interface. Additionally, in some implementations, the SMO Framework 105 can communicate directly with one or more RUs 140 via an 01 interface. The SMO Framework 105 also may include a Non-RT RIC 115 configured to support functionality of the SMO Framework 105.

[0045] The Non-RT RIC 115 may be configured to include a logical function that enables non-real-time control and optimization of RAN elements and resources, artificial intelligence (Al) / machine learning (ML) (AI / ML) workflows including model training and updates, or policy-based guidance of applications / features in the Near- RT RIC 125. The Non-RT RIC 115 may be coupled to or communicate with (such as via an Al interface) the Near-RT RIC 125. The Near-RT RIC 125 may be configured to include a logical function that enables near-real-time control and optimization of RAN elements and resources via data collection and actions over an interface (such as via an E2 interface) connecting one or more CUs 110, one or more DUs 130, or both, as well as an O-eNB, with the Near-RT RIC 125.

[0046] In some implementations, to generate AI / ML models to be deployed in the Near-RT RIC 125, the Non-RT RIC 115 may receive parameters or external enrichment information from external servers. Such information may be utilized by the Near-RT RIC 125 and may be received at the SMO Framework 105 or the Non-RT RIC 115 from non-network data sources or from network functions. In some examples, the Non-RT RIC 115 or the Near-RT RIC 125 may be configured to tune RAN behavior or performance. For example, the Non-RT RIC 115 may monitor long-term trends and patterns for performance and employ AI / ML models to perform corrective actions through the SMO Framework 105 (such as reconfiguration via 01) or via creation of RAN management policies (such as Al policies).

[0047] At least one of the CU 110, the DU 130, and the RU 140 may be referred to as a base station 102. Accordingly, a base station 102 may include one or more of the CU 110, the DU 130, and the RU 140 (each component indicated with dotted lines to signify that each component may or may not be included in the base station 102). The base station 102 provides an access point to the core network 120 for a UE 104. The base station 102 may include macrocells (high power cellular base station) and / or small cells (low power cellular base station). The small cells include femtocells, picocells, and microcells. A network that includes both small cell and macrocells may be known129025-2594WO01Qualcomm Ref. No. 2500350WO 12 / 63as a heterogeneous network. A heterogeneous network may also include Home Evolved Node Bs (eNBs) (HeNBs), which may provide service to a restricted group known as a closed subscriber group (CSG). The communication links between the RUs 140 and the UEs 104 may include uplink (UL) (also referred to as reverse link) transmissions from a UE 104 to an RU 140 and / or downlink (DL) (also referred to as forward link) transmissions from an RU 140 to a UE 104. The communication links may use multiple-input and multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, and / or transmit diversity. The communication links may be through one or more carriers. The base station 102 / UEs 104 may use spectrum up to F MHz (e.g., 5, 10, 15, 20, 100, 400, etc. MHz) bandwidth per carrier allocated in a carrier aggregation of up to a total of Fx MHz (x component carriers) used for transmission in each direction. The carriers may or may not be adjacent to each other. Allocation of carriers may be asymmetric with respect to DL and UL (e.g., more or fewer carriers may be allocated for DL than for UL). The component carriers may include a primary component carrier and one or more secondary component carriers. A primary component carrier may be referred to as a primary cell (PCell) and a secondary component carrier may be referred to as a secondary cell (SCell).

[0048] Certain UEs 104 may communicate with each other using device-to-device (D2D) communication link 158. The D2D communication link 158 may use the DL / UL wireless wide area network (WWAN) spectrum. The D2D communication link 158 may use one or more sidelink channels, such as a physical sidelink broadcast channel (PSBCH), a physical sidelink discovery channel (PSDCH), a physical sidelink shared channel (PSSCH), and a physical sidelink control channel (PSCCH). D2D communication may be through a variety of wireless D2D communications systems, such as for example, Bluetooth™ (Bluetooth is a trademark of the Bluetooth Special Interest Group (SIG)), Wi-Fi™ (Wi-Fi is a trademark of the Wi-Fi Alliance) based on the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard, LTE, or NR.

[0049] The wireless communications system may further include a Wi-Fi AP 150 in communication with UEs 104 (also referred to as Wi-Fi stations (STAs)) via communication link 154, e.g., in a 5 GHz unlicensed frequency spectrum or the like. When communicating in an unlicensed frequency spectrum, the UEs 104 / AP 150129025-2594WO01Qualcomm Ref. No. 2500350WO 13 / 63may perform a clear channel assessment (CCA) prior to communicating in order to determine whether the channel is available.

[0050] The electromagnetic spectrum is often subdivided, based on frequency / wavelength, into various classes, bands, channels, etc. In 5GNR, two initial operating bands have been identified as frequency range designations FR1 (410 MHz - 7.125 GHz) and FR2 (24.25 GHz - 52.6 GHz). Although a portion of FR1 is greater than 6 GHz, FR1 is often referred to (interchangeably) as a “sub-6 GHz” band in various documents and articles. A similar nomenclature issue sometimes occurs with regard to FR2, which is often referred to (interchangeably) as a “millimeter wave” band in documents and articles, despite being different from the extremely high frequency (EHF) band (30 GHz - 300 GHz) which is identified by the International Telecommunications Union (ITU) as a “millimeter wave” band.

[0051] The frequencies between FR1 and FR2 are often referred to as mid-band frequencies.Recent 5G NR studies have identified an operating band for these mid-band frequencies as frequency range designation FR3 (7.125 GHz - 24.25 GHz). Frequency bands falling within FR3 may inherit FR1 characteristics and / or FR2 characteristics, and thus may effectively extend features of FR1 and / or FR2 into midband frequencies. In addition, higher frequency bands are currently being explored to extend 5GNR operation beyond 52.6 GHz. For example, three higher operating bands have been identified as frequency range designations FR2-2 (52.6 GHz - 71 GHz), FR4 (71 GHz - 114.25 GHz), and FR5 (114.25 GHz - 300 GHz). Each of these higher frequency bands falls within the EHF band.

[0052] With the above aspects in mind, unless specifically stated otherwise, the term “sub-6GHz” or the like if used herein may broadly represent frequencies that may be less than 6 GHz, may be within FR1, or may include mid-band frequencies. Further, unless specifically stated otherwise, the term “millimeter wave” or the like if used herein may broadly represent frequencies that may include mid-band frequencies, may be within FR2, FR4, FR2-2, and / or FR5, or may be within the EHF band.

[0053] The base station 102 and the UE 104 may each include a plurality of antennas, such as antenna elements, antenna panels, and / or antenna arrays to facilitate beamforming. The base station 102 may transmit a beamformed signal 182 to the UE 104 in one or more transmit directions. The UE 104 may receive the beamformed signal from the base station 102 in one or more receive directions. The UE 104 may also transmit a129025-2594WO01Qualcomm Ref. No. 2500350WO 14 / 63beamformed signal 184 to the base station 102 in one or more transmit directions. The base station 102 may receive the beamformed signal from the UE 104 in one or more receive directions. The base station 102 / UE 104 may perform beam training to determine the best receive and transmit directions for each of the base station 102 / UE 104. The transmit and receive directions for the base station 102 may or may not be the same. The transmit and receive directions for the UE 104 may or may not be the same.

[0054] The base station 102 may include and / or be referred to as a gNB, Node B, eNB, an access point, a base transceiver station, a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS), an extended service set (ESS), a TRP, network node, network entity, network equipment, or some other suitable terminology. The base station 102 can be implemented as an integrated access and backhaul (IAB) node, a relay node, a sidelink node, an aggregated (monolithic) base station with a baseband unit (BBU) (including a CU and a DU) and an RU, or as a disaggregated base station including one or more of a CU, a DU, and / or an RU. The set of base stations, which may include disaggregated base stations and / or aggregated base stations, may be referred to as next generation (NG) RAN (NG-RAN).

[0055] The core network 120 may include an Access and Mobility Management Function (AMF) 161, a Session Management Function (SMF) 162, a User Plane Function (UPF) 163, a Unified Data Management (UDM) 164, one or more location servers 168, and other functional entities. The AMF 161 is the control node that processes the signaling between the UEs 104 and the core network 120. The AMF 161 supports registration management, connection management, mobility management, and other functions. The SMF 162 supports session management and other functions. The UPF 163 supports packet routing, packet forwarding, and other functions. The UDM 164 supports the generation of authentication and key agreement (AKA) credentials, user identification handling, access authorization, and subscription management. The one or more location servers 168 are illustrated as including a Gateway Mobile Location Center (GMLC) 165 and a Location Management Function (LMF) 166. However, generally, the one or more location servers 168 may include one or more location / positioning servers, which may include one or more of the GMLC 165, the LMF 166, a position determination entity (PDE), a serving mobile location center (SMLC), a mobile positioning center (MPC), or the like. The GMLC 165 and the129025-2594WO01Qualcomm Ref. No. 2500350WO 15 / 63LMF 166 support UE location services. The GMLC 165 provides an interface for clients / applications (e.g., emergency services) for accessing UE positioning information. The LMF 166 receives measurements and assistance information from the NG-RAN and the UE 104 via the AMF 161 to compute the position of the UE 104. The NG-RAN may utilize one or more positioning methods in order to determine the position of the UE 104. Positioning the UE 104 may involve signal measurements, a position estimate, and an optional velocity computation based on the measurements. The signal measurements may be made by the UE 104 and / or the base station 102 serving the UE 104. The signals measured may be based on one or more of a satellite positioning system (SPS) 170 (e.g., one or more of a Global Navigation Satellite System (GNSS), global position system (GPS), non-terrestrial network (NTN), or other satellite position / location system), LTE signals, wireless local area network (WLAN) signals, Bluetooth signals, a terrestrial beacon system (TBS), sensor-based information (e.g., barometric pressure sensor, motion sensor), NR enhanced cell ID (NRE-CID) methods, NR signals (e.g., multi -round trip time (Multi -RTT), DL angle- of-departure (DL-AoD), DL time difference of arrival (DL-TDOA), UL time difference of arrival (UL-TDOA), and UL angle-of-arrival (UL-AoA) positioning), and / or other systems / signals / sensors.

[0056] Examples of UEs 104 include a cellular phone, a smart phone, a session initiation protocol (SIP) phone, a laptop, a personal digital assistant (PDA), a satellite radio, a global positioning system, a multimedia device, a video device, a digital audio player (e.g., MP3 player), a camera, a game console, a tablet, a smart device, a wearable device, a vehicle, an electric meter, a gas pump, a large or small kitchen appliance, a healthcare device, an implant, a sensor / actuator, a display, or any other similar functioning device. Some of the UEs 104 may be referred to as loT devices (e.g., parking meter, gas pump, toaster, vehicles, heart monitor, etc.). The UE 104 may also be referred to as a station, a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communications device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other suitable terminology. In some scenarios, the term UE may also apply to one or more companion devices such as in129025-2594WO01Qualcomm Ref. No. 2500350WO 16 / 63a device constellation arrangement. One or more of these devices may collectively access the network and / or individually access the network.

[0057] Referring again to FIG. 1, in certain aspects, the UE 104 may have a shortened CP component 198 that may be configured to receive an indication of a reduced CP length associated with at least one DL transmission, receive the at least one DL transmission using the reduced CP length, and transmit a response to the at least one DL transmission. In certain aspects, the base station 102 may have a CP shortening component 199 that may be configured to transmit an indication of a reduced CP length associated with at least one DL transmission and transmit the at least one DL transmission using the reduced CP length. Although the following description may be focused on 5G NR, the concepts described herein may be applicable to other similar areas, such as LTE, LTE-A, CDMA, GSM, and other wireless technologies.

[0058] FIG. 2A is a diagram 200 illustrating an example of a first subframe within a 5G NR frame structure. FIG. 2B is a diagram 230 illustrating an example of DL channels within a 5G NR subframe. FIG. 2C is a diagram 250 illustrating an example of a second subframe within a 5G NR frame structure. FIG. 2D is a diagram 280 illustrating an example of UL channels within a 5G NR subframe. The 5G NR frame structure may be frequency division duplexed (FDD) in which for a particular set of subcarriers (carrier system bandwidth), subframes within the set of subcarriers are dedicated for either DL or UL, or may be time division duplexed (TDD) in which for a particular set of subcarriers (carrier system bandwidth), subframes within the set of subcarriers are dedicated for both DL and UL. In the examples provided by FIGs. 2A, 2C, the 5G NR frame structure is assumed to be TDD, with subframe 4 being configured with slot format 28 (with mostly DL), where D is DL, U is UL, and F is flexible for use between DL / UL, and subframe 3 being configured with slot format 1 (with all UL). While subframes 3, 4 are shown with slot formats 1, 28, respectively, any particular subframe may be configured with any of the various available slot formats 0-61. Slot formats 0, 1 are all DL, UL, respectively. Other slot formats 2-61 include a mix of DL, UL, and flexible symbols. UEs are configured with the slot format (dynamically through DL control information (DCI), or semi- statically / statically through radio resource control (RRC) signaling) through a received slot format indicator (SFI). Note that the description infra applies also to a 5G NR frame structure that is TDD.129025-2594WO01Qualcomm Ref. No. 2500350WO 17 / 63

[0059] FIGs. 2A-2D illustrate a frame structure, and the aspects of the present disclosure may be applicable to other wireless communication technologies, which may have a different frame structure and / or different channels. A frame (10 ms) may be divided into 10 equally sized subframes (1 ms). Each subframe may include one or more time slots. Subframes may also include mini-slots, which may include 7, 4, or 2 symbols. Each slot may include 14 or 12 symbols, depending on whether the cyclic prefix (CP) is normal or extended. For normal CP, each slot may include 14 symbols, and for extended CP, each slot may include 12 symbols. The symbols on DL may be CP orthogonal frequency division multiplexing (OFDM) (CP-OFDM) symbols. The symbols on UL may be CP-OFDM symbols (for high throughput scenarios) or discrete Fourier transform (DFT) spread OFDM (DFT-s-OFDM) symbols (for power limited scenarios; limited to a single stream transmission). The number of slots within a subframe is based on the CP and the numerology. The numerology defines the subcarrier spacing (SCS) (see Table 1). The symbol length / duration may scale with 1 / SCS.Table 1: Numerology, SCS, and CP

[0060] For normal CP (14 symbols / slot), different numerologies p 0 to 4 allow for 1, 2, 4, 8, and 16 slots, respectively, per subframe. For extended CP, the numerology 2 allows for 4 slots per subframe. Accordingly, for normal CP and numerology p, there are 14 symbols / slot and 2^ slots / subframe. The subcarrier spacing may be equal to 2 / z* 15 kHz, where . is the numerology 0 to 4. As such, the numerology p=0 has a subcarrier spacing of 15 kHz and the numerology p=4 has a subcarrier spacing of 240 kHz. The symbol length / duration is inversely related to the subcarrier spacing. FIGs.129025-2594WO01Qualcomm Ref. No. 2500350WO 18 / 632A-2D provide an example of normal CP with 14 symbols per slot and numerology p=2 with 4 slots per subframe. The slot duration is 0.25 ms, the subcarrier spacing is 60 kHz, and the symbol duration is approximately 16.67 ps. Within a set of frames, there may be one or more different bandwidth parts (BWPs) (see FIG. 2B) that are frequency division multiplexed. Each BWP may have a particular numerology and CP (normal or extended).

[0061] A resource grid may be used to represent the frame structure. Each time slot includes a resource block (RB) (also referred to as physical RBs (PRBs)) that extends 12 consecutive subcarriers. The resource grid is divided into multiple resource elements (REs). The number of bits carried by each RE depends on the modulation scheme.

[0062] As illustrated in FIG. 2 A, some of the REs carry reference (pilot) signals (RS) for the UE. The RS may include demodulation RS (DM-RS) (indicated as R for one particular configuration, but other DM-RS configurations are possible) and channel state information reference signals (CSI-RS) for channel estimation at the UE. The RS may also include beam measurement RS (BRS), beam refinement RS (BRRS), and phase tracking RS (PT-RS).

[0063] FIG. 2B illustrates an example of various DL channels within a subframe of a frame.The physical downlink control channel (PDCCH) carries DCI within one or more control channel elements (CCEs) (e.g., 1, 2, 4, 8, or 16 CCEs), each CCE including six RE groups (REGs), each REG including 12 consecutive REs in an OFDM symbol of an RB. A PDCCH within one BWP may be referred to as a control resource set (CORESET). A UE is configured to monitor PDCCH candidates in a PDCCH search space (e.g., common search space, UE-specific search space) during PDCCH monitoring occasions on the CORESET, where the PDCCH candidates have different DCI formats and different aggregation levels. Additional BWPs may be located at greater and / or lower frequencies across the channel bandwidth. A primary synchronization signal (PSS) may be within symbol 2 of particular subframes of a frame. The PSS is used by a UE 104 to determine subframe / symbol timing and a physical layer identity. A secondary synchronization signal (SSS) may be within symbol 4 of particular subframes of a frame. The SSS is used by a UE to determine a physical layer cell identity group number and radio frame timing. Based on the physical layer identity and the physical layer cell identity group number, the UE can determine a physical cell identifier (PCI). Based on the PCI, the UE can determine129025-2594WO01Qualcomm Ref. No. 2500350WO 19 / 63the locations of the DM-RS. The physical broadcast channel (PBCH), which carries a master information block (MIB), may be logically grouped with the PSS and SSS to form a synchronization signal (SS)ZPBCH block (also referred to as SS block (SSB)). The MIB provides a number of RBs in the system bandwidth and a system frame number (SFN). The physical downlink shared channel (PDSCH) carries user data, broadcast system information not transmitted through the PBCH such as system information blocks (SIBs), and paging messages.

[0064] As illustrated in FIG. 2C, some of the REs carry DM-RS (indicated as R for one particular configuration, but other DM-RS configurations are possible) for channel estimation at the base station. The UE may transmit DM-RS for the physical uplink control channel (PUCCH) and DM-RS for the physical uplink shared channel (PUSCH). The PUSCH DM-RS may be transmitted in the first one or two symbols of the PUSCH. The PUCCH DM-RS may be transmitted in different configurations depending on whether short or long PUCCHs are transmitted and depending on the particular PUCCH format used. The UE may transmit sounding reference signals (SRS). The SRS may be transmitted in the last symbol of a subframe. The SRS may have a comb structure, and a UE may transmit SRS on one of the combs. The SRS may be used by a base station for channel quality estimation to enable frequencydependent scheduling on the UL.

[0065] FIG. 2D illustrates an example of various UL channels within a subframe of a frame.The PUCCH may be located as indicated in one configuration. The PUCCH carries uplink control information (UCI), such as scheduling requests, a channel quality indicator (CQI), a precoding matrix indicator (PMI), a rank indicator (RI), and hybrid automatic repeat request (HARQ) acknowledgment (ACK) (HARQ-ACK) feedback (i.e., one or more HARQ ACK bits indicating one or more ACK and / or negative ACK (NACK)). The PUSCH carries data, and may additionally be used to carry a buffer status report (BSR), a power headroom report (PHR), and / or UCI.

[0066] FIG. 3 is a block diagram of a base station 310 in communication with a UE 350 in an access network. In the DL, Internet protocol (IP) packets may be provided to a controller / processor 375. The controller / processor 375 implements layer 3 and layer 2 functionality. Layer 3 includes a radio resource control (RRC) layer, and layer 2 includes a service data adaptation protocol (SDAP) layer, a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, and a medium access control129025-2594WO01Qualcomm Ref. No. 2500350WO 20 / 63(MAC) layer. The controller / processor 375 provides RRC layer functionality associated with broadcasting of system information (e.g., MIB, SIBs), RRC connection control (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release), inter radio access technology (RAT) mobility, and measurement configuration for UE measurement reporting; PDCP layer functionality associated with header compression / decompression, security (ciphering, deciphering, integrity protection, integrity verification), and handover support functions; RLC layer functionality associated with the transfer of upper layer packet data units (PDUs), error correction through ARQ, concatenation, segmentation, and reassembly of RLC service data units (SDUs), re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto transport blocks (TBs), demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority handling, and logical channel prioritization.

[0067] The transmit (TX) processor 316 and the receive (RX) processor 370 implement layer 1 functionality associated with various signal processing functions. Layer 1, which includes a physical (PHY) layer, may include error detection on the transport channels, forward error correction (FEC) coding / decoding of the transport channels, interleaving, rate matching, mapping onto physical channels, modulation / demodulation of physical channels, and MIMO antenna processing. The TX processor 316 handles mapping to signal constellations based on various modulation schemes (e.g., binary phase-shift keying (BPSK), quadrature phase-shift keying (QPSK), M-phase-shift keying (M-PSK), M-quadrature amplitude modulation (M-QAM)). The coded and modulated symbols may then be split into parallel streams. Each stream may then be mapped to an OFDM subcarrier, multiplexed with a reference signal (e.g., pilot) in the time and / or frequency domain, and then combined together using an Inverse Fast Fourier Transform (IFFT) to produce a physical channel carrying a time domain OFDM symbol stream. The OFDM stream is spatially precoded to produce multiple spatial streams. Channel estimates from a channel estimator 374 may be used to determine the coding and modulation scheme, as well as for spatial processing. The channel estimate may be derived from a reference signal and / or channel condition feedback transmitted by the UE 350. Each spatial stream129025-2594WO01Qualcomm Ref. No. 2500350WO 21 / 63may then be provided to a different antenna 320 via a separate transmitter 318Tx. Each transmitter 318Tx may modulate a radio frequency (RF) carrier with a respective spatial stream for transmission.

[0068] At the UE 350, each receiver 354Rx receives a signal through its respective antenna 352. Each receiver 354Rx recovers information modulated onto an RF carrier and provides the information to the receive (RX) processor 356. The TX processor 368 and the RX processor 356 implement layer 1 functionality associated with various signal processing functions. The RX processor 356 may perform spatial processing on the information to recover any spatial streams destined for the UE 350. If multiple spatial streams are destined for the UE 350, they may be combined by the RX processor 356 into a single OFDM symbol stream. The RX processor 356 then converts the OFDM symbol stream from the time-domain to the frequency domain using a Fast Fourier Transform (FFT). The frequency domain signal includes a separate OFDM symbol stream for each subcarrier of the OFDM signal. The symbols on each subcarrier, and the reference signal, are recovered and demodulated by determining the most likely signal constellation points transmitted by the base station 310. These soft decisions may be based on channel estimates computed by the channel estimator 358. The soft decisions are then decoded and deinterleaved to recover the data and control signals that were originally transmitted by the base station 310 on the physical channel. The data and control signals are then provided to the controller / processor 359, which implements layer 3 and layer 2 functionality.

[0069] The controller / processor 359 can be associated with at least one memory 360 that stores program codes and data. The at least one memory 360 may be referred to as a computer-readable medium. In the UL, the controller / processor 359 provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, and control signal processing to recover IP packets. The controller / processor 359 is also responsible for error detection using an ACK and / or NACK protocol to support HARQ operations.

[0070] Similar to the functionality described in connection with the DL transmission by the base station 310, the controller / processor 359 provides RRC layer functionality associated with system information (e.g., MIB, SIBs) acquisition, RRC connections, and measurement reporting; PDCP layer functionality associated with header compression / decompression, and security (ciphering, deciphering, integrity129025-2594WO01Qualcomm Ref. No. 2500350WO 22 / 63protection, integrity verification); RLC layer functionality associated with the transfer of upper layer PDUs, error correction through ARQ, concatenation, segmentation, and reassembly of RLC SDUs, re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto TBs, demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority handling, and logical channel prioritization.

[0071] Channel estimates derived by a channel estimator 358 from a reference signal or feedback transmitted by the base station 310 may be used by the TX processor 368 to select the appropriate coding and modulation schemes, and to facilitate spatial processing. The spatial streams generated by the TX processor 368 may be provided to different antenna 352 via separate transmitters 354Tx. Each transmitter 354Tx may modulate an RF carrier with a respective spatial stream for transmission.

[0072] The UL transmission is processed at the base station 310 in a manner similar to that described in connection with the receiver function at the UE 350. Each receiver 318Rx receives a signal through its respective antenna 320. Each receiver 318Rx recovers information modulated onto an RF carrier and provides the information to a RX processor 370.

[0073] The controller / processor 375 can be associated with at least one memory 376 that stores program codes and data. The at least one memory 376 may be referred to as a computer-readable medium. In the UL, the controller / processor 375 provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, control signal processing to recover IP packets. The controller / processor 375 is also responsible for error detection using an ACK and / or NACK protocol to support HARQ operations.

[0074] At least one of the TX processor 368, the RX processor 356, and the controller / processor 359 may be configured to perform aspects in connection with the shortened CP component 198 of FIG. 1.

[0075] At least one of the TX processor 316, the RX processor 370, and the controller / processor 375 may be configured to perform aspects in connection with the CP shortening component 199 of FIG. 1.

[0076] In addition to higher capability devices wireless communication systems may support reduced capability devices, which may be referred to as RedCap devices, RedCap UEs, NR light devices, low-tier devices, or lower tier devices, among other examples. Among others, 129025-2594WO01Qualcomm Ref. No. 2500350WO 23 / 63examples of higher capability devices include premium smartphones, V2X devices, URLLC devices, eMBB devices, etc. Among other examples, reduced capability devices may include wearables, industrial wireless sensor networks (IWSN), surveillance cameras, low-end smartphones, etc. Reduced capability UEs may communicate based on various types of wireless communication. For example, smart wearables may transmit or receive communication based on low power wide area (LPWA) / mMTC, relaxed loT devices may transmit or receive communication based on URLLC, sensors / cameras may transmit or receive communication based on eMBB, etc.

[0077] In some examples, a reduced capability UE may have an uplink transmission power of at least 10 dB less than that a higher capability UE. As another example, a reduced capability UE may have reduced transmission bandwidth or reception bandwidth than other UEs. For instance, a reduced capability UE may have an operating bandwidth between 5 MHz and 10MHz for both transmission and reception, in contrast to other UEs which may have 20-100 MHz bandwidth. As a further example, a reduced capability UE may have a reduced number of reception antennas in comparison to other UEs. For instance, a reduced capability UE may have only a single receive antenna and may experience a lower equivalent receive signal to noise ratio (SNR) in comparison to higher capability UEs that may have multiple antennas. Reduced capability UEs may also have reduced computational complexity than other UEs. In some aspects of wireless communication reducing power consumption at UEs, and specifically at RedCap UEs. One approach addressing power saving is shifting more and more processing from the UE side to the base station side. A significant source of power consumption that may be shifted to the base station is channel equalization for a DL transmission, e.g., Rx equalization may be replaced with a Tx equalization.

[0078] To the extent that channel equalization can be shifted from the UE to a transmitting device such as a base station, a complexity of processing a received DL transmission may be reduced. In some aspects, by shifting the equalization from the UE to the transmitting device, the UE may also save power associated with a demodulation of the received DL transmission prior to a decoding process. In practical terms, this may allow the receiver (e.g., the UE) to operate in a lower-power mode, which may be particularly beneficial for low power constrained systems, where power efficiency is a higher priority.

[0079] Tx equalization may be specifically suitable for DL transmission, as the Tx side (e.g., a base station) may have more advanced and / or a greater computation capability than129025-2594WO01Qualcomm Ref. No. 2500350WO 24 / 63a receiving device (e.g., a UE or a RedCap UE). The use of Tx equalization, in some aspects, may extend a battery lifetime of a portable device, enhances the overall system efficiency, and may also mitigate, reduce, or improve, a power dissipation budget (or thermal budget) relating to how fast the receiving device generates and / or dissipates thermal energy. Tx equalization may be helpful to lower-power devices (such as XR glasses, VR, and AR devices, etc.) within a network.

[0080] As an example, XR traffic may refer to wireless communications for technologies such as virtual reality (VR), mixed reality (MR), and / or augmented reality (AR). VR may refer to technologies in which a user is immersed in a simulated experience that is similar or different from the real world. A user may interact with a VR system through a VR headset or a multi -projected environment that generates realistic images, sounds, and other sensations that simulate a user’s physical presence in a virtual environment. MR may refer to technologies in which aspects of a virtual environment and a real environment are mixed. AR may refer to technologies in which objects residing in the real world are enhanced via computer-generated perceptual information, sometimes across multiple sensory modalities, such as visual, auditory, haptic, somatosensory, and / or olfactory. An AR system may incorporate a combination of real and virtual worlds, real-time interaction, and accurate three- dimensional registration of virtual objects and real objects. In an example, an AR system may overlay sensory information (e.g., images) onto a natural environment and / or mask real objects from the natural environment. XR traffic may include video data and / or audio data. XR traffic may be transmitted by a base station and received by a UE or the XR traffic may be transmitted by a UE and received by a base station. In some aspects, a device that exchanges XR traffic may be a lower-power device, have one or more reduced capabilities, and / or have reduced complexity.

[0081] FIG. 4 is a diagram 400 illustrating a representation of aspects in connection with a channel for wireless communication. Diagram 400 illustrates a representation 410 of a transmitted signal 412 (shown as an impulse “fc”, where “fc” is a frequency-domain index). The transmitted signal 412 traverses a channel 420 between a wireless transmitting device and a wireless receiving device which may affect the transmitted signal (which may be represented as a matrixwhere the matrix Hkmay vary over a frequency domain, e.g., be different for different values of k) and may additionally be associated with a noise (e.g., additive white Gaussian noise (AWGN),129025-2594WO01Qualcomm Ref. No. 2500350WO 25 / 63“IVfc”). Channel 420, in some aspects, may represent any transmission path from a transmitting device to a receiving device, e.g., an over the air interface. Diagram 400 illustrates an additional representation 430 of a received signal 432 (e.g., an impulse response “Kfc”) based on the transmitted signal 412 and the channel 420. In general, based on a transmitted signal Xka receiver may receive a signal represented as Yk= Hk- Xk+ Nk, where Ykmay be associated with a channel support 434. The channel support may be measured and / or specified in units of time such as seconds, milliseconds, microseconds, slots, symbols. In a high signal to noise ratio (SNR) environment and / or scenario, a first channel support 434 may be identified based on a duration of a portion of the impulse response having a power greater than a threshold power 423. In a low SNR environment and / or scenario, a second channel support 436 may be identified based on a duration of a portion of the impulse response having a power greater than a threshold power 425, where the different threshold powers may be selected based on a power associated with the noise (e.g., to be above a power associated with the noise by at least an offset or factor). The channel support, in some aspects, may be a measure of a dispersion associated with a channel in a time domain.

[0082] In some aspects, a CP may be appended to a DL message before transmission to compensate for the channel support (e.g., for the dispersion experienced during transmission over the channel). A CP may allow a receiving device to account for dispersion experienced during transmission over a channel. A channel support (e.g., a measure of a dispersion associated with the channel) may determine, or be associated with, a minimum length of a CP that may be used to compensate for the channel support and / or dispersion. For example, the more dispersive the channel is, the longer the minimum CP length becomes. While the minimum length of the CP, i.e., the minimum number of samples added at the beginning of each time dispersive OFDM symbol, depends on the channel length (or the channel support), in practice, regardless of the channel’s support, the CP length may be a constant (e.g., ~7% of the symbol duration and / or a transmitted signal). Based on the constant CP length (e.g., as defined in a standard), the overhead associated with the CP is fixed.

[0083] FIG. 5 is a diagram 500 illustrating an OFDM transmitter 510 and an OFDM receiver 530 associated with a transmit-side equalization in accordance with some aspects of the disclosure. An OFDM transmitter 510, in some aspects, may receive bits 501 to transmit to a receiving device (e.g., OFDM receiver 530) to decode to produce bits129025-2594WO01Qualcomm Ref. No. 2500350WO 26 / 63531. The OFDM transmitter 510 may allocate, or map, the received bits 501 to a set of constellation points, allocate, or map, the constellation points to a set of REs, and the perform a Tx equalization 520. The Tx equalization 520 may be implemented as one of many available methods, (e.g., Tx Zero Forcing (ZF), Tx minimum mean square error (MMSE), Tomlinson-Harashima precoding (THP), etc.). Whichever method of Tx equalization is performed, the basic approach is the same, adding the Tx equalization (e.g., a linear and / or nonlinear component implementing the Tx equalization 520) to the Tx chain, e.g., as part of the OFDM transmitter 510 prior to the signal being transmitted over the channel). The Tx equalization 520, in some aspects, may leverage knowledge about the channel (e.g., based on channel information received from a receiving device) to cancel the influence of the channel.

[0084] As a result of the Tx equalization, the overall equivalent channel that the signal experiences, from the point prior to Tx equalization until the slicer at the Rx side, is expected to be canceled. Accordingly, a received signal may be represented by Yk= ( / + Ak) ■ Xk+ Nk, where I is the identity matrix and Akis the residual (post equalization and channel) error matrix of the overall transmission and reception. Hence, for a pure and perfect Tx equalization, Afcshould be zero, and the overall channel is canceled. In practice, the Tx equalization 520 may reduce a first channel support 522 in the absence of Tx equalization to a second channel support 524 (a shorter channel support). Where the second channel support 524 is shorter than the first channel support 522 based on the same threshold power 523.

[0085] For example, for a non-pure (or imperfect) equalization, the residual channel can be expressed by the term: Hres[k] = (I + Ak). As discussed above, a minimum length of a CP to compensate for the channel support may correspond to the channel support (e.g., the time domain duration) of the IFFT of Afc(where the identity matrix effectively has no support, or only 1 tap support in a time domain, since it is constantly flat in a frequency domain). If a CP is shorter than the support of Afc, it might cause inter symbol interference (ISI), which might limit the noise floor, and as a result, the attainable data rate.

[0086] The residual error (Ak) and / or the associated residual channel (Hres[k] = ( / + Ak)),e.g., the error / channel after Tx equalization, is expected to have a much shorter support compared to the original channel which may enable a dramatic shortening of the minimum CP length. A reduced CP length, in some aspects, may be associated129025-2594WO01Qualcomm Ref. No. 2500350WO 27 / 63with reduced overhead and improved spectral efficiency and / or additional functionality. In some aspects, resources associated with a standard CP length that are not used to transmit a shortened CP may be used to transmit additional pilots, transmit additional data, or for additional PHY calibration and / or measurements procedures. Each of these uses may improve spectral efficiency and / or link robustness when using a Tx Equalized waveform (and the reduced length and / or shortened CP enabled by the shorter channel support associated with the channel after equalization and / or the residual channel).

[0087] In some aspects, the magnitude, or length, of the post-equalization channel support may depend on the Tx equalization method and / or criteria used (e.g., a ZF method or criteria, a MMSE method or criteria, or a linear and / or nonlinear THP equalization). For example, when implementing a MMSE based method (e.g., using MMSE criteria), the residual post equalization channel support may depend on the operational signal to noise ratio (SNR).

[0088] For a low SNR scenario (e.g., in the presence of a higher relative power associated with noise), the relevant and / or identified residual channel support (e.g., the portion of the impulse response above a threshold power) may be shorter because shortened- CP-incurred ISI may be negligible with respect to the (thermal) noise. For example, if a threshold power (e.g., threshold power 423 or threshold power 425) used to determine the channel support is a function of the power associated with a noise term (e.g., N ), then the channel support may be shorter based on a higher relative power associated with the noise (e.g., a relative power that is 5% of a signal power instead of 1%). In contrast, for a high SNR scenario, the sensitivity to any residual channel support may be higher and a longer portion of the resulting residual channel may be considered to prevent a related noise floor (e.g., from shortened-CP-incurred ISI) limitation at the high SNR operational point.

[0089] In some aspects, many factors can lead to a residual error and / or residual channel support (e.g., post Tx equalization error and / or channel support). For example, the completeness of the channel inversion may affect the residual error and may, in some aspects, be based on a Tx equalization method (with some Tx equalization methods achieving more complete channel inversions). Channel aging, e.g., using outdated channel information regarding the channel when performing the Tx equalization, may contribute to the residual error and / or residual channel support. For example, channel129025-2594WO01Qualcomm Ref. No. 2500350WO 28 / 63aging may be based on changing conditions of the channel between the transmitting and receiving devices, where the mobility of a receiving device may be correlated with a speed of channel aging (e.g., a higher mobility may be correlated with a speed of channel information becoming outdated or inversely correlated to a usable, or valid, lifetime of channel information). In some aspects, residual timing errors caused by the synchronization loops at the receiver may contribute to the residual error and / or residual channel support

[0090] As discussed above, a Tx equalization aims at “inverting” the channel to have effectively a “no channel” scenario. However, different Tx equalization methods may have different costs and benefits. For example, a perfect inversion (e.g., associated with a ZF method) may be associated with increased complexity or other costs. Similarly, other methods (e.g., MMSE, or THP MMSE) may allow compliance with some constraints (e.g., a maximum Tx power constraint) and may be associated with reduced complexity at the cost of not completely inverting (or cancelling the effects of) the channel. Accordingly, a transmitting device may be able to determine an optimal Tx equalization method for a particular communication. For example, the transmitting device may evaluate (e.g., on the Tx side) the residual channel, a delay spread of the residual channel, and / or the ISI in the case of shortening the CP according to a selected Tx equalization method (similar to an evaluation of a channel or delay spread performed by a receiving device). In some aspects, the ISI evaluation (e.g., for different candidate Tx equalization methods) may take into account an ISI due to the equalization method as well as an ISI introduced by a synchronization error based on a receiving devices timing synchronization loops. The length of a shortened CP and / or the magnitude of a CP shortening may be determined based on the ISI evaluation (or calculation) and an operational thermal SNR (e.g., to ensure that the ISI introduced by the CP shortening and / or shortened CP is negligible with respect to, or is not greater than, the operational thermal SNR). The determination and / or selection of a Tx equalization method for the Tx equalization from a plurality of candidate Tx equalization methods may then be based on the completeness of the Tx equalization methods, the performance of the Tx equalization methods, the evaluated ISI, the characteristics of the communication, and any other relevant criteria.

[0091] Various aspects relate generally to shortening a default CP length (e.g., a default CP length defined in a standard) when implementing and / or using the Tx equalization129025-2594WO01Qualcomm Ref. No. 2500350WO 29 / 63such that the overall channel that the signal experiences has a much shorter support (e.g., is associated with less dispersion in time). Some aspects more specifically relate to a network configuring and / or indicating a shortened CP as a result of Tx equalization (e.g., implementing a channel inversion based on channel knowledge at the transmitter). Some aspects relate to different implementations and uses of the portion of a symbol associated with a standard CP length not used for transmitting the CP based on a shortened CP. In some examples, a wireless device may be configured to receive an indication of a reduced CP length associated with at least one DL transmission, receive the at least one DL transmission using the reduced CP length, and transmit a response to the at least one DL transmission. In some aspects, a network device may be configured to transmit an indication of a reduced CP length associated with at least one DL transmission and transmit the at least one DL transmission using the reduced CP length.

[0092] Particular aspects of the subject matter described in this disclosure can be implemented to realize one or more of the following potential advantages. In some examples, by indicating and / or using a shortened CP length, the described techniques can be used to improve wireless communications, improve spectral efficiency, and / or introduce additional functions (e.g., associated with using the remaining CP resources to increase throughput, add a time domain (TD) pilot, enable a listening mode, etc.).

[0093] FIGs. 6A and 6B illustrate example resource uses in accordance with some aspects of the disclosure. FIG. 6A is a diagram 600 illustrating an example use of resources saved by CP shortening in a first set of OFDM symbols. Diagram 600 illustrates that a set of OFDM symbols (e.g., including OFDM symbol 620) may be associated with an original CP length 610 (e.g., ~7% of an OFDM symbol, which may not be drawn to scale for clarity), a shortened CP length 615, and “extra” resources 625 (e.g., resources previously used for CP transmission that are now available for repurposing). Each OFDM symbol, in some aspects, may include first resources 601 associated with a guard band, second resources 603 associated with additional data and / or an additional TD pilot(s), third resources 605 associated with the shortened CP, and fourth resources 607 associated with a (primary and / or standard) data transmission.

[0094] In some aspects, a slot (and symbol) duration may be preserved (or common) across slots using a shortened CP length and slots using the standard (or legacy) CP length (e.g., for transmissions not using Tx equalization) to maintain a synchronization129025-2594WO01Qualcomm Ref. No. 2500350WO 30 / 63between transmissions using the shortened CP and other transmissions which do not use the shortened proposed CP. Based on using the common slot (and symbol) length, additional time domain resources (e.g., “extra” resources 625) may be available for one or more purposes. For example, in some aspects, second resources 603 within the resources associated with the original CP length 610 may be used to transmit a TD pilot (e.g., a TD pilot, and associated guard bands, may be added at the beginning of the resources associated with the original CP length 610). The TD pilot, in some aspects, may be used to measure RF impairment and / or other distortions. The additional TD pilot may enable faster synchronization loop updates, automatic gain control (AGC) updates, RF calibration procedures, channel time correlation estimations, etc., where the TD pilot may be designed according to its target.

[0095] In some aspects, second resources 603 within the resources associated with the original CP length 610 (e.g., non-shortened CP length) may be used to transmit additional data (e.g., with some constellation determined according to limitations associated with ensuring no damage to the rest of the configured and / or transmitted data and / or pilots in the slot or symbol). In the above examples, the configuration of the shortened CP (and the use of the “extra” resources) may be determined to ensure that the added data and / or TD pilot does not cause a threshold level of 1ST To avoid ISI from the additional data and / or TD pilot(s), the transmitting device may configure (e.g., include in the configuration information for the shortened CP) guard bands before and after the additional data and / or TD pilot(s). In some aspects, a transmitting device (e.g., a base station) may transmit a request to a served receiving device (e.g., a UE) for an indication of a preferred usage of the “extra” resources from a defined (e.g., defined in a standard and known without separate configuration) or configured (e.g., in a previously received configuration) set of options.

[0096] FIG. 6B is a diagram 650 illustrating an example use of resources saved by CP shortening in a first set of OFDM symbols. Diagram 650 illustrates that a set of OFDM symbols (e.g., including OFDM symbol 670) may be associated with an original CP length 660 (e.g., a non-shortened CP length) (e.g., ~7% of an OFDM symbol, which may not be drawn to scale for clarity), a shortened CP length 665, and “extra” resources 675 (e.g., resources previously used for CP transmission that are now available for repurposing). Each OFDM symbol, in some aspects, may include first resources 653 associated with a quiet and / or listening band, second resources 655129025-2594WO01Qualcomm Ref. No. 2500350WO 31 / 63associated with the shortened CP, and third resources 657 associated with a (primary and / or standard) data transmission.

[0097] In some aspects, a slot (and symbol) duration may be preserved (or common) across slots using a shortened CP length and slots using the standard (or legacy) CP length (e.g., for transmissions not using Tx equalization) to maintain a synchronization between transmissions using the shortened CP and other transmissions which do not use the shortened proposed CP. Based on using the common slot (and symbol) length, additional time domain resources (e.g., “extra” resources 675) may be available for one or more purposes. For example, in some aspects, first resources 653 within the resources associated with the original CP length 660 may be used to enable a listening mode. If a listening mode is enabled and / or activated, the transmitting device (e.g., a base station or gNB) omits, or refrains from, configuring and / or scheduling data in the remaining allocation (e.g., the “extra” resources 675) due to the CP shortening. In some aspects, based on the transmitting device omitting a transmission during the remaining allocation, a receiving device (e.g., a UE) may be enabled to perform a sensing and / or measurement on (e.g., “listen” to) other UL / DL transmissions and evaluate a magnitude and / or direction of a detected interference. Thus, the UE may choose to operate in a different beam or to perform “null steering” towards the direction of the detected interference. The listening mode, in some aspects, may enable and / or aid an evaluation of an Rx noise autocorrelation (e.g., the performance of a zero power based Rnn evaluation).

[0098] FIG. 7 is a call flow diagram 700 illustrating a method of wireless communication in accordance with some aspects of the disclosure. The method is illustrated in relation to a base station 702 (e.g., as an example of a transmitting device such as a network device or network node that may include one or more components of a disaggregated base station) in communication with a UE 704 (e.g., as an example of a receiving wireless device). The functions ascribed to the base station 702, in some aspects, may be performed by one or more components of a network entity, a network node, or a network device (a single network entity / node / device or a disaggregated network entity / node / device as described above in relation to FIG. 1). Similarly, the functions ascribed to the UE 704, in some aspects, may be performed by one or more components of a wireless device supporting communication with a network entity / node / device. Accordingly, references to “transmitting” in the description below129025-2594WO01Qualcomm Ref. No. 2500350WO 32 / 63may be understood to refer to a first component of the base station 702 (or the UE 704) outputting (or providing) an indication of the content of the transmission to be transmitted by a different component of the base station 702 (or the UE 704). Similarly, references to “receiving” in the description below may be understood to refer to a first component of the base station 702 (or the UE 704) receiving a transmitted signal and outputting (or providing) the received signal (or information based on the received signal) to a different component of the base station 702 (or the UE 704).

[0099] The UE 704, in some aspects, may provide information to the base station 702 that can be used to determine (e.g., at 720, as will be discussed below) aspects of a CP shortening operation and / or configuration such as a shortened CP length, a Tx equalization method, an estimated channel to be inverted, and a duration between channel reporting and / or estimation operations. For example, the UE 704 may transmit, and the base station 702 may receive, synchronization uncertainty information 710 indicating a synchronization uncertainty at the UE, where the reported value may indicate a time associated with the support of its timing synchronization loops error. For example, while the overall channel may be effectively canceled by a Tx equalization (e.g., may be reduced to the residual channel Hresbased on the quality of the equalization) at the base station 702, the UE 704 may still have some synchronization loop error. While the Tx equalization and related CP shortening may use a maximum synchronization uncertainty and / or error allowed at a receiver (e.g., based on a standard), in many cases the actual synchronization uncertainty and / or error at the receiver may be less than the maximum allowed (e.g., a support may be shorter than a maximum). In some aspects, using the actual synchronization uncertainty and / or error (e.g., as reported in synchronization uncertainty information 710) to determine a CP shortening (e.g., a length of a shortened CP) may result in a shorter CP and greater spectral efficiency and / or lower overhead. The synchronization loop residual error bound, in some aspects, may depend on operational SNR, the pilot(s) used and / or addressed for synchronization error estimation and the parameters associated with the pilot(s), and synchronization loop implementation aspects. This synchronization error and / or uncertainty, in some aspects, contributes to the minimum CP duration (e.g., a minimum CP duration associated with avoiding ISI) and may be considered in determining a CP shortening129025-2594WO01Qualcomm Ref. No. 2500350WO 33 / 63configuration. Accordingly, the indication of the synchronization uncertainty information 710 from the UE 704 to the base station 702 may result in, or allow for, a determination (e.g., at 720, as will be discussed below) of a more effective, or accurate, shortened CP length, Tx equalization method, and / or Tx equalization-based waveform usage.

[0100] In some aspects, the UE 704 may transmit, and the base station 702 may receive, mobility information 712 indicating a mobility of the UE (e.g., a speed and / or velocity associated with the movement of the UE). In some aspects, the Tx equalization method is more effective over time in low mobility and / or static scenarios (for purposes of this discussion it is assumed that the base station 702 is fixed and that the mobility is a function of the movement of the UE 704). For example, in non-static scenarios, a channel estimation may experience “channel aging” in which the channel estimation becomes outdated as the receiver (e.g., the UE 704) moves away from the position for which channel information (e.g., CSI) has been reported and for which the channel estimation has been performed and / or calculated. Using an outdated channel estimation, in some aspects, may degrade the performance of the Tx equalization (and the related CP shortening) by introducing channel effects that are not accounted for (e.g., not removed or inverted) by the Tx equalization (e.g., regardless of the Tx equalization method used) and increasing the residual channel support (e.g., the IFFT of Afc). In turn, the increased residual channel support may reduce the ability to shorten the CP (e.g., may increase a minimum CP length to avoid ISI) and / or will result in more ISI for a configured shortened CP based on the assumption that the Tx equalization is inverting the actual channel.

[0101] Accordingly, the base station 702 may (e.g., at 720, as will be discussed below) calculate a refreshing period (e.g., a maximum time between CSI reporting from the UE 704 and or channel estimation operations) which may be a function of the channel correlation in time. In some aspects, the channel correlation in time may be calculated based on channel estimations performed over time or may be assumed based on a reported and / or detected mobility. For example, the base station 702 may detect the movement and / or mobility of the UE 704, the UE 704 may report a mobility or an experienced doppler (e.g., in mobility information 712), of the base station 702 may perform channel measurements of UL transmissions and calculate a channel correlation in, or over, time. The base station 702, in some aspects, may evaluate the129025-2594WO01Qualcomm Ref. No. 2500350WO 34 / 63developed doppler and find the approximated outdated channel error and / or the expected channel aging bound based on the report of the mobility or the experienced doppler and / or the channel measurements of the UL transmissions.

[0102] In some aspects, the base station 702 may determine to perform a new channel estimation and / or evaluation and update an associated Tx equalization operation based on the mobility information and / or the detected channel aging. The base station may (e.g., at 720, as will be discussed below) determine, based on the received mobility information 712 and / or other indications of a rate of channel aging, a refresh rate associated with a CP shortening configuration and indicate a related periodicity of CSI reporting to the UE 704. In the absence of a new channel estimation and / or evaluation (and associated update to the Tx equalization operation) a channel estimation error may depend on, or be a function of, the interval length since a previous channel estimation and / or evaluation and the degree of mobility of the UE and / or a channel coherency time (e.g., a characteristic time associated with a threshold channel correlation .over time). In some aspects, the base station may evaluate the added error due to ISI, for example, by learning, online or offline (e.g., via training), the outdated channel distortion with, and without, another OFDM symbol near the examined OFDM symbol. If this distortion is determined to not be negligible with respect to the residual error expected based on the Tx equalization method (Afc), the base station 702 may (e.g., at 732, as will be discussed below) determine to lengthen the CP length to reduce the ISI.

[0103] The UE 704, may transmit, and the base station 702 may receive, channel information 714. Channel information 714, in some aspects, may include CSI or other information used by the base station 702 to perform a channel estimation. The base station 702 may transmit, and the UE 704 may receive, a request 716 for the UE 704 to indicate a capability of the UE 704 to support, and / or a suggestion for, one or more uses of resources associated with the standard CP length that are not used by the shortened CP. For example, the use of the resources may be any of the uses discussed above in relation to FIGs. 6 A and 6B. In some aspects, the uses may include a first transmission of a time domain pilot signal, where the time domain pilot signal is preceded by a first guard band and is followed by a second guard band, a second transmission of data, where the second transmission of the data is preceded by the first guard band and is followed by the second guard band, or omitting, at a source of the at least one DL129025-2594WO01Qualcomm Ref. No. 2500350WO 35 / 63transmission, a transmission to allow for the UE to evaluate interference from at least one interference source.

[0104] In response to the request 716, the UE 704 may transmit, and the base station 702 may receive, indication 718 indicating a capability of the UE 704 to support, and / or a suggestion for, one or more uses of resources associated with the standard CP length that are not used by the shortened CP. Based on one or more of the synchronization uncertainty information 710, the mobility information 712, the channel information 714, and / or the indication 718, the base station may determine, at 720, a configuration for the CP shortening. As discussed above, determining the CP shortening configuration at 720 may include performing a channel estimation (e.g., based on the channel information 714), selecting a Tx equalization method, determining a shortened CP length (e.g., based on the synchronization uncertainty information 710, the expected Akfrom the selected Tx equalization method, and / or an expected upper bound for the additional error from channel aging related to the mobility information 712), a use for the “extra” resources (e.g., based on the indication 718), and determining a channel re-evaluation / refresh rate and / or a channel estimate valid lifetime (e.g., based on the mobility information 712).

[0105] Based on the determination at 720, the base station 702 may transmit, and the UE 704 may receive, a CP shortening configuration 722. The CP shortening configuration 722, in some aspects, may include an indication of a reduced (or shortened) CP length (e.g., relative to a default and / or standard CP length) associated with at least one DL transmission and may also include an indication of a use of the resources (e.g., as described above in relation to FIGs. 6A and 6B) which may, or may not, be the suggested use indicated in the indication 718, a configuration of the resources associated with the use of the resources (e.g., an indication of guard band resources associated with the first guard band and the second guard band, an indication of a configuration of the data, an indication of the configuration and / or purpose of the TD pilot(s), or an indication of listening and / or quiet resources for measuring signals from other devices), and / or an indication of a period between channel information reporting (e.g., a CSI reporting periodicity and / or frequency).

[0106] The base station 702 may transmit a shortened CP DL transmission 724, and the UE 704 may, at 726, receive the shortened CP DL transmission 724 (e.g., a DL transmission based on the CP shortening configuration 722). For example, the UE 704129025-2594WO01Qualcomm Ref. No. 2500350WO 36 / 63may receive the shortened CP DL transmission 724 including a set of symbols as described above in relation to FIGs. 6A or 6B using the CP resources not used to transmit the shortened CP for additional data, TD pilot(s), or quiet resources. If the shortened CP DL transmission 724 includes the additional data or the TD pilot(s), the UE may process the additional data or the TD pilot(s) as indicated by the shortened CP DL transmission 724. Similarly, if the shortened CP DL transmission 724 includes the quiet, or listening, resources, the UE 704 may evaluate the interference from at least one interference source. Based on the evaluated interference, the UE 704 may, as part of receiving the shortened CP DL transmission at 726, adjust, a reception parameter at the UE. For example, the UE may choose to operate in a different beam or to perform “null steering” towards the interference direction. In some aspects, based on the TD pilot(s) or the evaluated interference, the UE 704 may, as part of receiving the shortened CP DL transmission at 726, measure RF impairment and other distortions that may enable faster synchronization loop updates, AGC updates, RF calibration procedures, channel time correlation estimations, etc., or may evaluate the Rx noise autocorrelation (zero power based Rnn evaluation).

[0107] Based on the received shortened CP DL transmission 724, the UE 704 may transmit UL transmission 728, where the UL transmission 728 may be in response to the shortened CP DL transmission 724. In some aspects, the UL transmission 728, may include an updated indication of a capability of the UE 704 to support, and / or an updated suggestion (or updated preference indication) for, one or more uses of resources associated with the standard CP length that are not used by the shortened CP. Similarly, the UL transmission 728 may include updated synchronization uncertainty information or updated mobility information. After additional shortened CP DL transmissions (not shown) during a time period associated with the CP shortening configuration 722 (a valid lifetime of the CP shortening configuration 722, e.g., based on the mobility information 712 or related channel aging characteristics), the UE 704 may transmit updated channel information 730. The updated channel information 730, in some aspects, may include CSI or other information used by the base station 702 to perform an updated channel estimation.

[0108] Based on one or more of the synchronization uncertainty information 710 (or updated synchronization uncertainty information included in UL transmission 728), the mobility information 712 (or updated mobility information included in UL129025-2594WO01Qualcomm Ref. No. 2500350WO 37 / 63transmission 728), the updated channel information 730, and / or the indication 718 (or the updated indication included in UL transmission 728), the base station 702 may determine, at 732, an updated configuration for the CP shortening. As discussed above, determining the CP shortening configuration at 732 may include performing a channel estimation (e.g., based on the channel information 730), selecting a Tx equalization method, determining a shortened CP length (e.g., based on the synchronization uncertainty information, the expected Akfrom the selected Tx equalization method, and / or an expected upper bound for the additional error from channel aging related to the mobility information), a use for the “extra” resources (e.g., based on the indication of the capability or preference of the UE 704), and determining a channel re-evaluation / refresh rate and / or a channel estimate valid lifetime (e.g., based on the mobility information).

[0109] Based on the determination at 732, the base station 702 may transmit, and the UE 704 may receive, an updated CP shortening configuration 734. The CP shortening configuration 734, in some aspects, may include an indication of an updated reduced (or shortened) CP length (e.g., relative to a default and / or standard CP length) associated with at least one DL transmission and may also include an indication of an updated use of the resources (e.g., as described above in relation to FIGs. 6A and 6B) which may, or may not, be the suggested use indicated in the indication 718 or included in the UL transmission 728, a configuration of the resources associated with the use of the resources (e.g., an indication of guard band resources associated with the first guard band and the second guard band, an indication of a configuration of the data, an indication of the configuration and / or purpose of the TD pilot(s), or an indication of listening and / or quiet resources for measuring signals from other devices), and / or an indication of a period between channel information reporting (e.g., a CSI reporting periodicity and / or frequency).

[0110] The base station 702 may transmit a shortened CP DL transmission 736, and the UE 704 may, at 738, receive the shortened CP DL transmission 736 (e.g., a DL transmission based on the CP shortening configuration 734). For example, the UE 704 may receive the shortened CP DL transmission 736 including a set of symbols as described above in relation to FIGs. 6A or 6B using the CP resources not used to transmit the shortened CP for additional data, TD pilot(s), or quiet resources. If the shortened CP DL transmission 736 includes the additional data or the TD pilot(s), the129025-2594WO01Qualcomm Ref. No. 2500350WO 38 / 63UE may process the additional data or the TD pilot(s) as indicated by the shortened CP DL transmission 736. Similarly, if the shortened CP DL transmission 736 includes the quiet, or listening, resources, the UE 704 may evaluate the interference from at least one interference source. Based on the evaluated interference, the UE 704 may, as part of receiving the shortened CP DL transmission at 738, adjust, a reception parameter at the UE. For example, the UE may choose to operate in a different beam or to perform “null steering” towards the interference direction. In some aspects, based on the TD pilot(s) or the evaluated interference, the UE 704 may, as part of receiving the shortened CP DL transmission at 738, measure RF impairment and other distortions that may enable faster synchronization loop updates, AGC updates, RF calibration procedures, channel time correlation estimations, etc., or may evaluate the Rx noise autocorrelation (zero power based Rnn evaluation).[OHl] Based on the received shortened CP DL transmission 736, the UE 704 may transmit UL transmission 740, where the UL transmission 740 may be in response to the shortened CP DL transmission 736. Additional updates to the CP shortening configuration, in some aspects, may be performed periodically or may be triggered by a detected deterioration of the Tx equalization (e.g., based on an increased error rate, a reduced channel quality, etc.)

[0112] FIG. 8 is a flowchart 800 of a method of wireless communication. The method may be performed by a receiving wireless device such as a UE (e.g., the UE 104, 704; the OFDM receiver 530; the apparatus 1104). In some aspects, the UE may exchange information with a transmitting device for CP shortening. Exchanging information, in some aspects, may include one or more of transmitting an indication of a synchronization uncertainty at the UE, transmitting an indication of a mobility of the UE, transmitting channel information, receiving a request for a suggested use of resources associated with transmitting a default CP having the default CP length that are not used to transmit a reduced CP having the reduced CP length, and transmitting an indication of the suggested use of the resources. In some aspects, the use of the resources may be indicated to be a first transmission of a time domain pilot signal, wherein the time domain pilot signal is preceded by a first guard band and is followed by a second guard band, a second transmission of data, wherein the second transmission of the data is preceded by the first guard band and is followed by the second guard band, or omitting, at a source of the at least one DL transmission, a129025-2594WO01Qualcomm Ref. No. 2500350WO 39 / 63transmission to allow for the UE to evaluate interference from at least one interference source. For example, referring to FIG. 7, the UE 704 may transmit one or more of synchronization uncertainty information 710, mobility information 712, channel information 714, or indication 718 (e.g., based on receiving request 716).

[0113] At 812, the UE may receive configuration information for a reduced CP length associated with at least one DL transmission. For example, 812 may be performed by application processor(s) 1106, cellular baseband processor(s) 1124, transceiver(s) 1122, antenna(s) 1180, and / or shortened CP component 198 of FIG. 11. In some aspects, the reduced CP length may be reduced relative to a default CP length (e.g., a default CP length associated with a numerology associated with the at least one DL transmission). The configuration information, in some aspects, may include an indication of (or indicate) a use of the resources (e.g., a use of the resources determined by the transmitting device that may be different from the use indicated during the exchange of information). If the use of the resources includes one of the first transmission of the time domain pilot signal or the second transmission of the data, the configuration information for the reduced CP length may include an indication of guard band resources associated with the first guard band and the second guard band. In some aspects, the configuration information may include an indication of (or indicate) a timing (or frequency) associated with transmitting channel information from the UE (e.g., a CSI report frequency or period / periodicity), where the frequency may be based on the indicated mobility of the UE (e.g., the mobility indicated during the exchange of information). For example, referring to FIGs. 6A, 6B, and 7, the UE 704 may receive CP shortening configuration 722 that may indicate one of the TD resource allocations illustrated in FIGs. 6A and 6B.

[0114] At 814, the UE may receive the at least one DL transmission using the reduced CP length. The UE may decode, based on the reduced CP length, the at least one DL transmission using a decoding method consistent with a transmission based on the equalization performed at the source of the transmission. For example, 814 may be performed by application processor(s) 1106, cellular baseband processor(s) 1124, transceiver(s) 1122, antenna(s) 1180, and / or shortened CP component 198 of FIG. 11. In some aspects, the at least one DL transmission may be based on an equalization (e.g., a Tx equalization) performed at a source of (e.g., a transmitting device that transmits) the at least one DL transmission. For example, referring to FIGs. 6A, 6B,129025-2594WO01Qualcomm Ref. No. 2500350WO 40 / 63and 7, the UE 704 may receive shortened CP DL transmission 724 having one of the TD resource allocations illustrated in FIGs. 6A and 6B based on the CP shortening configuration 722.

[0115] At 818, the UE may transmit a response to the at least one DL transmission. For example, 818 may be performed by application processor(s) 1106, cellular baseband processor(s) 1124, transceiver s) 1122, antenna(s) 1180, and / or shortened CP component 198 of FIG. 11. Referring to FIG. 7, for example, the UE 704 may transmit the UL transmission 728.

[0116] In some aspects, the UE may perform additional operations associated with using a shortened CP length. In some aspects, the additional operations may include one or more of transmitting updated channel information, receiving an additional DL transmission based on a second equalization based on a second channel estimate performed at the source of the at least one DL transmission, receiving an indication of an updated reduced CP length, wherein the updated reduced CP length is based on the second channel estimate, evaluating interference from at least one interference source, and adjusting a reception parameter at the UE based on the interference. The additional operations, in some aspects, may include transmitting an updated suggested use of the resources. In some aspects, transmitting the updated channel information, receiving the additional DL transmission based on the second equalization, and / or receiving the indication of the updated reduced CP length may occur after a time based on the indicated and / or detected mobility of the UE. In some aspects adjusting the reception parameter at the UE based on the interference may include operating in a different beam or to perform “null steering” towards the interference direction. For example, referring to FIGs. 6A, 6B, and 7, the UE 704 may receive, at 726, shortened CP DL transmission 724 having one of the TD resource allocations illustrated in FIGs.6A and 6B based on the CP shortening configuration 722, the UE may transmit updated channel information 730, and / or the UE may receive one or more of CP shortening configuration 734 or shortened CP DL transmission 736. In some aspects, instead of performing the additional operations, the UE may return to exchange (updated) information with the transmitting device for updating the CP shortening.

[0117] FIG. 9 is a flowchart 900 of a method of wireless communication. The method may be performed by a receiving wireless device such as a UE (e.g., the UE 104, 704; the OFDM receiver 530; the apparatus 1104). At 901, the UE may exchange information129025-2594WO01Qualcomm Ref. No. 2500350WO 41 / 63with a transmitting device for CP shortening. Exchanging information at 901, in some aspects, may include one or more of transmitting, at 902, an indication of a synchronization uncertainty at the UE, transmitting, at 903, an indication of a mobility of the UE, transmitting, at 904, channel information, receiving, at 905, a request for a suggested use of resources associated with transmitting a default CP having the default CP length that are not used to transmit a reduced CP having the reduced CP length, and transmitting, at 906, an indication of the suggested use of the resources. For example, 901-906 may be performed by application processor(s) 1106, cellular baseband processor(s) 1124, transceiver(s) 1122, antenna(s) 1180, and / or shortened CP component 198 of FIG. 11. In some aspects, the use of the resources may be indicated to be a first transmission of a time domain pilot signal, wherein the time domain pilot signal is preceded by a first guard band and is followed by a second guard band, a second transmission of data, wherein the second transmission of the data is preceded by the first guard band and is followed by the second guard band, or omitting, at a source of the at least one DL transmission, a transmission to allow for the UE to evaluate interference from at least one interference source. For example, referring to FIG. 7, the UE 704 may transmit one or more of synchronization uncertainty information 710, mobility information 712, channel information 714, or indication 718 (e.g., based on receiving request 716).

[0118] At 912, the UE may receive configuration information for a reduced CP length associated with at least one DL transmission. For example, 912 may be performed by application processor(s) 1106, cellular baseband processor(s) 1124, transceiver(s) 1122, antenna(s) 1180, and / or shortened CP component 198 of FIG. 11. In some aspects, the reduced CP length may be reduced relative to a default CP length (e.g., a default CP length associated with a numerology associated with the at least one DL transmission). The configuration information, in some aspects, may include an indication of (or indicate) a use of the resources (e.g., a use of the resources determined by the transmitting device that may be different from the use indicated at 906). If the use of the resources includes one of the first transmission of the time domain pilot signal or the second transmission of the data, the configuration information for the reduced CP length may include an indication of guard band resources associated with the first guard band and the second guard band. In some aspects, the configuration information may include an indication of (or indicate) a129025-2594WO01Qualcomm Ref. No. 2500350WO 42 / 63timing (or frequency) associated with transmitting channel information from the UE (e.g., a CSI report frequency or period / periodicity), where the frequency may be based on the indicated mobility of the UE (e.g., the mobility indicated at 903). For example, referring to FIGs. 6A, 6B, and 7, the UE 704 may receive CP shortening configuration 722 that may indicate one of the TD resource allocations illustrated in FIGs. 6A and 6B.

[0119] At 914, the UE may receive the at least one DL transmission using the reduced CP length. The UE may, at 916, decode, based on the reduced CP length, the at least one DL transmission using a decoding method consistent with a transmission based on the equalization performed at the source of the transmission. For example, 914 and 916 may be performed by application processor(s) 1106, cellular baseband processor(s) 1124, transceiver(s) 1122, antenna(s) 1180, and / or shortened CP component 198 of FIG. 11. In some aspects, the at least one DL transmission may be based on an equalization performed at a source of (e.g., a transmitting device that transmits) the at least one DL transmission. For example, referring to FIGs. 6A, 6B, and 7, the UE 704 may receive shortened CP DL transmission 724 having one of the TD resource allocations illustrated in FIGs. 6A and 6B based on the CP shortening configuration 722.

[0120] At 918, the UE may transmit a response to the at least one DL transmission. For example, 918 may be performed by application processor(s) 1106, cellular baseband processor(s) 1124, transceiver(s) 1122, antenna(s) 1180, and / or shortened CP component 198 of FIG. 11. Referring to FIG. 7, for example, the UE 704 may transmit the UL transmission 728.

[0121] At 920, the UE may perform additional operations associated with using a shortened CP length. In some aspects, the additional operations may include one or more of transmitting, at 921, updated channel information, receiving, at 922, an additional DL transmission based on a second equalization based on a second channel estimate performed at the source of the at least one DL transmission, receiving, at 923, an indication of an updated reduced CP length, wherein the updated reduced CP length is based on the second channel estimate, evaluating, at 924, interference from at least one interference source, and adjusting, at 925, a reception parameter at the UE based on the interference. For example, 920-925 may be performed by application processor(s) 1106, cellular baseband processor(s) 1124, transceiver s) 1122,129025-2594WO01Qualcomm Ref. No. 2500350WO 43 / 63antenna(s) 1180, and / or shortened CP component 198 of FIG. 11. The additional operations, in some aspects, may include transmitting an updated suggested use of the resources. In some aspects, transmitting the updated channel information at 921, receiving the additional DL transmission based on the second equalization at 922, and / or receiving the indication of the updated reduced CP length at 923 may occur after a time based on the mobility of the UE indicated at 903. In some aspects adjusting the reception parameter at the UE based on the interference may include operating in a different beam or to perform “null steering” towards the interference direction. For example, referring to FIGs. 6A, 6B, and 7, the UE 704 may receive, at 726, shortened CP DL transmission 724 having one of the TD resource allocations illustrated in FIGs. 6A and 6B based on the CP shortening configuration 722, the UE may transmit updated channel information 730, and / or the UE may receive one or more of CP shortening configuration 734 or shortened CP DL transmission 736. In some aspects, instead of performing the additional operations, the UE may return to 901 to exchange (updated) information with the transmitting device for updating the CP shortening.

[0122] FIG. 10 is a flowchart 1000 of a method of wireless communication. The method may be performed by a transmitting wireless device such as a network device or base station ((e.g., the base station 102, 702; the OFDM transmitter 510; the network entity 1102, 1202). In some aspects, the base station may exchange information with a receiving device for CP shortening. Exchanging information, in some aspects, may include one or more of receiving an indication of a synchronization uncertainty at the base station, receiving an indication of a mobility of the base station, receiving channel information, transmitting a request for a suggested use of resources associated with transmitting a default CP having the default CP length that are not used to transmit a reduced CP having the reduced CP length, and receiving an indication of the suggested use of the resources. In some aspects, the use of the resources may be indicated to be a first transmission of a time domain pilot signal, wherein the time domain pilot signal is preceded by a first guard band and is followed by a second guard band, a second transmission of data, wherein the second transmission of the data is preceded by the first guard band and is followed by the second guard band, or omitting, at a source of the at least one DL transmission, a transmission to allow for the base station to evaluate interference from at least one interference source. For129025-2594WO01Qualcomm Ref. No. 2500350WO 44 / 63example, referring to FIG. 7, the base station 702 may receive one or more of synchronization uncertainty information 710, mobility information 712, channel information 714, or indication 718 (e.g., based on transmitting request 716).

[0123] In some aspects, the base station may determine characteristics of the CP shortening.For example, the base station may generate, based on the channel information, a channel estimate for a channel between the network device and the UE. The base station may further determine, based on the exchanged information and the channel estimate, a reduced CP length. In some aspects, the base station may determine a time associated with a validity of the channel estimation and associated reduced CP length based on channel characteristics affecting a channel aging and / or based on a reported and / or detected mobility of the receiving device (e.g., the UE). For example, referring to FIG. 7, the base station 702 may determine at 720 a configuration for the CP shortening.

[0124] At 1022, the base station may transmit configuration information for a reduced CP length associated with at least one DL transmission. For example, 1022 may be performed by CU processor(s) 1212, DU processor(s) 1232, RU processor(s) 1242, transceiver(s) 1246, antenna(s) 1280, and / or CP shortening component 199 of FIG.12. In some aspects, the reduced CP length may be reduced relative to a default CP length (e.g., a default CP length associated with a numerology associated with the at least one DL transmission). The configuration information, in some aspects, may include an indication of (or indicate) a use of the resources (e.g., a use of the resources determined by the receiving device that may be different from the use indicated by the receiving device / UE). If the use of the resources includes one of the first transmission of the time domain pilot signal or the second transmission of the data, the configuration information for the reduced CP length may include an indication of guard band resources associated with the first guard band and the second guard band. In some aspects, the configuration information may include an indication of (or indicate) a timing (or frequency) associated with receiving channel information from the base station (e.g., a CSI report frequency or period / periodicity), where the frequency may be based on the indicated mobility of the base station (e.g., the mobility indicated by the receiving device / UE). For example, referring to FIGs. 6A, 6B, and 7, the base station 702 may transmit CP shortening configuration 722 that may indicate one of the TD resource allocations illustrated in FIGs. 6A and 6B.129025-2594WO01Qualcomm Ref. No. 2500350WO 45 / 63

[0125] At 1026, the base station may transmit the at least one DL transmission using the reduced CP length. For example, 1026 may be performed by CU processor(s) 1212, DU processor(s) 1232, RU processor(s) 1242, transceiver(s) 1246, antenna(s) 1280, and / or CP shortening component 199 of FIG. 12. In some aspects, to transmit the at least one DL transmission using the reduced CP length, the base station may perform, based on the channel estimate, an equalization (e.g., a Tx equalization) on the at least one DL transmission before appending the CP having the reduced CP length. For example, referring to FIGs. 6A, 6B, and 7, the base station 702 may transmit shortened CP DL transmission 724 having one of the TD resource allocations illustrated in FIGs.6A and 6B based on the CP shortening configuration 722.

[0126] In some aspects, the base station may perform additional operations associated with using a shortened CP length. In some aspects, the additional operations may include one or more of receiving updated channel information, performing an updated channel estimation based on the updated channel information (e.g., to generate a second channel estimate for the channel between the base station and the UE), transmitting an additional DL transmission based on a second equalization based on the second channel estimate generated by the base station, transmitting an indication of an updated reduced CP length, wherein the updated reduced CP length is based on the second channel estimate. The additional operations, in some aspects, may include receiving an updated suggested use of the resources. In some aspects, receiving the updated channel information, transmitting the additional DL transmission based on the second equalization, and / or transmitting the indication of the updated reduced CP length may occur after a time based on an indicated and / or detected mobility of the UE. For example, referring to FIGs. 6A, 6B, and 7, the base station 702 may transmit, at 726, shortened CP DL transmission 724 having one of the TD resource allocations illustrated in FIGs. 6A and 6B based on the CP shortening configuration 722, the base station may receive updated channel information 730, and / or the base station may transmit one or more of CP shortening configuration 734 or shortened CP DL transmission 736. In some aspects, instead of performing the additional operations, the base station may return to exchange (updated) information with the receiving device for updating the CP shortening.

[0127] FIG. 11 is a diagram 1100 illustrating an example of a hardware implementation for an apparatus 1104. The apparatus 1104 may be a UE, a component of a UE, or may129025-2594WO01Qualcomm Ref. No. 2500350WO 46 / 63implement UE functionality. In some aspects, the apparatus 1104 may include at least one cellular baseband processor 1124 (also referred to as a modem) coupled to one or more transceivers 1122 (e.g., cellular RF transceiver). The cellular baseband processor(s) 1124 may include at least one on-chip memory 1124'. In some aspects, the apparatus 1104 may further include one or more subscriber identity modules (SIM) cards 1120 and at least one application processor 1106 coupled to a secure digital (SD) card 1108 and a screen 1110. The application processor(s) 1106 may include on-chip memory 1106'. In some aspects, the apparatus 1104 may further include a Bluetooth module 1112, a WLAN module 1114, an SPS module 1116 (e.g., GNSS module), one or more sensor modules 1118 (e.g., barometric pressure sensor / altimeter; motion sensor such as inertial measurement unit (IMU), gyroscope, and / or accelerometer(s); light detection and ranging (LIDAR), radio assisted detection and ranging (RADAR), sound navigation and ranging (SONAR), magnetometer, audio and / or other technologies used for positioning), additional memory modules 1126, a power supply 1130, and / or a camera 1132. The Bluetooth module 1112, the WLAN module 1114, and the SPS module 1116 may include an on-chip transceiver (TRX) (or in some cases, just a receiver (RX)). The Bluetooth module 1112, the WLAN module 1114, and the SPS module 1116 may include their own dedicated antennas and / or utilize one or more antennas 1180 for communication. The cellular baseband processor(s) 1124 communicates through the transceiver(s) 1122 via the one or more antennas 1180 with the UE 104 and / or with an RU associated with a network entity 1102. The cellular baseband processor(s) 1124 and the application processor(s) 1106 may each include a computer-readable medium / memory 1124', 1106', respectively. The additional memory modules 1126 may also be considered a computer-readable medium / memory. Each computer-readable medium / memory 1124', 1106', 1126 may be non -transitory. The cellular baseband processor(s) 1124 and the application processor(s) 1106 are each responsible for general processing, including the execution of software stored on the computer-readable medium / memory. The software, when executed by the cellular baseband processor(s) 1124 / application processor(s) 1106, causes the cellular baseband processor(s) 1124 / application processor(s) 1106 to perform the various functions described supra. The cellular baseband processor(s) 1124 and the application processor(s) 1106 are configured to perform the various functions described supra based at least in part of the information stored in the129025-2594WO01Qualcomm Ref. No. 2500350WO 47 / 63memory. That is, the cellular baseband processor(s) 1124 and the application processor(s) 1106 may be configured to perform a first subset of the various functions described supra without information stored in the memory and may be configured to perform a second subset of the various functions described supra based on the information stored in the memory. The computer-readable medium / memory may also be used for storing data that is manipulated by the cellular baseband processor(s) 1124 / application processor(s) 1106 when executing software. The cellular baseband processor(s) 1124 / application processor(s) 1106 may be a component of the UE 350 and may include the at least one memory 360 and / or at least one of the TX processor 368, the RX processor 356, and the controller / processor 359. In one configuration, the apparatus 1104 may be at least one processor chip (modem and / or application) and include just the cellular baseband processor(s) 1124 and / or the application processor(s) 1106, and in another configuration, the apparatus 1104 may be the entire UE (e.g., see UE 350 of FIG. 3) and include the additional modules of the apparatus 1104.

[0128] As discussed supra, the shortened CP component 198 may be configured to receive an indication of a reduced CP length associated with at least one DL transmission, receive the at least one DL transmission using the reduced CP length, and transmit a response to the at least one DL transmission. The shortened CP component 198 may be within the cellular baseband processor(s) 1124, the application processor(s) 1106, or both the cellular baseband processor(s) 1124 and the application processor(s) 1106. The shortened CP component 198 may be one or more hardware components specifically configured to carry out the stated processes / algorithm, implemented by one or more processors configured to perform the stated processes / algorithm, stored within a computer-readable medium for implementation by one or more processors, or some combination thereof. When multiple processors are implemented, the multiple processors may perform the stated processes / algorithm individually or in combination. As shown, the apparatus 1104 may include a variety of components configured for various functions. In one configuration, the apparatus 1104, and in particular the cellular baseband processor(s) 1124 and / or the application processor(s) 1106, may include means for receiving configuration information for a reduced CP length associated with at least one DL transmission. The apparatus 1104, and in particular the cellular baseband processor(s) 1124 and / or the application processor(s)129025-2594WO01Qualcomm Ref. No. 2500350WO 48 / 631106, may include means for receiving the at least one DL transmission using the reduced CP length. The apparatus 1104, and in particular the cellular baseband processor(s) 1124 and / or the application processor(s) 1106, may include means for transmitting a response to the at least one DL transmission. The apparatus 1104, and in particular the cellular baseband processor(s) 1124 and / or the application processor(s) 1106, may include means for receiving a request for a suggested use of resources associated with transmitting a default CP having the default CP length that are not used to transmit a reduced CP having the reduced CP length. The apparatus 1104, and in particular the cellular baseband processor(s) 1124 and / or the application processor(s) 1106, may include means for transmitting a first indication of the suggested use of the resources. The apparatus 1104, and in particular the cellular baseband processor(s) 1124 and / or the application processor(s) 1106, may include means for evaluating the interference from the at least one interference source. The apparatus 1104, and in particular the cellular baseband processor(s) 1124 and / or the application processor(s) 1106, may include means for adjusting, based on the interference, a reception parameter at the UE. The apparatus 1104, and in particular the cellular baseband processor(s) 1124 and / or the application processor(s) 1106, may include means for decoding, based on the reduced CP length, the at least one DL transmission using a decoding method consistent with a transmission based on the equalization performed at the source of the transmission. The apparatus 1104, and in particular the cellular baseband processor(s) 1124 and / or the application processor(s) 1106, may include means for transmitting an indication of a mobility of the UE. The apparatus 1104, and in particular the cellular baseband processor(s) 1124 and / or the application processor(s) 1106, may include means for receiving, after a time based on the indication of the mobility of the UE, an additional DL transmission based on a second equalization based on a second channel estimate performed at the source of the at least one DL transmission. The apparatus 1104, and in particular the cellular baseband processor(s) 1124 and / or the application processor(s) 1106, may include means for receiving, after the time based on the second indication of the mobility of the UE, a third indication of an updated reduced CP length. The apparatus 1104, and in particular the cellular baseband processor(s) 1124 and / or the application processor(s) 1106, may include means for transmitting, based on the indicated frequency, updated channel information. The apparatus 1104, and in particular the129025-2594WO01Qualcomm Ref. No. 2500350WO 49 / 63cellular baseband processor(s) 1124 and / or the application processor(s) 1106, may include means for transmitting an additional indication of a synchronization uncertainty at the UE. The apparatus 1104 may further include means for performing any of the aspects described in connection with the flowcharts in FIGs. 8 or 9, and / or performed by the UE in the communication flow of FIG. 7. The means may be the shortened CP component 198 of the apparatus 1104 configured to perform the functions recited by the means. As described supra, the apparatus 1104 may include the TX processor 368, the RX processor 356, and the controller / processor 359. As such, in one configuration, the means may be the TX processor 368, the RX processor 356, and / or the controller / processor 359 configured to perform the functions recited by the means.

[0129] FIG. 12 is a diagram 1200 illustrating an example of a hardware implementation for a network entity 1202. The network entity 1202 may be a BS, a component of a BS, or may implement BS functionality. The network entity 1202 may include at least one of a CU 1210, a DU 1230, or an RU 1240. For example, depending on the layer functionality handled by the CP shortening component 199, the network entity 1202 may include the CU 1210; both the CU 1210 and the DU 1230; each of the CU 1210, the DU 1230, and the RU 1240; the DU 1230; both the DU 1230 and the RU 1240; or the RU 1240. The CU 1210 may include at least one CU processor 1212. The CU processor(s) 1212 may include on-chip memory 1212'. In some aspects, the CU 1210 may further include additional memory modules 1214 and a communications interface 1218. The CU 1210 communicates with the DU 1230 through a midhaul link, such as an Fl interface. The DU 1230 may include at least one DU processor 1232. The DU processor(s) 1232 may include on-chip memory 1232'. In some aspects, the DU 1230 may further include additional memory modules 1234 and a communications interface 1238. The DU 1230 communicates with the RU 1240 through a fronthaul link. The RU 1240 may include at least one RU processor 1242. The RU processor(s) 1242 may include on-chip memory 1242'. In some aspects, the RU 1240 may further include additional memory modules 1244, one or more transceivers 1246, one or more antennas 1280, and a communications interface 1248. The RU 1240 communicates with the UE 104. The on-chip memory 1212', 1232', 1242' and the additional memory modules 1214, 1234, 1244 may each be considered a computer-readable medium / memory. Each computer-readable medium / memory129025-2594WO01Qualcomm Ref. No. 2500350WO 50 / 63may be non-transitory. Each of the processors 1212, 1232, 1242 is responsible for general processing, including the execution of software stored on the computer- readable medium / memory. The software, when executed by the corresponding processor(s) causes the processor(s) to perform the various functions described supra. The computer-readable medium / memory may also be used for storing data that is manipulated by the processor(s) when executing software.

[0130] As discussed supra, the CP shortening component 199 may be configured to transmit an indication of a reduced CP length associated with at least one DL transmission and transmit the at least one DL transmission using the reduced CP length. The CP shortening component 199 may be within one or more processors of one or more of the CU 1210, DU 1230, and the RU 1240. The CP shortening component 199 may be one or more hardware components specifically configured to carry out the stated processes / algorithm, implemented by one or more processors configured to perform the stated processes / algorithm, stored within a computer-readable medium for implementation by one or more processors, or some combination thereof. When multiple processors are implemented, the multiple processors may perform the stated processes / algorithm individually or in combination. The network entity 1202 may include a variety of components configured for various functions. In one configuration, the network entity 1202 may include means for transmitting configuration information for a reduced CP length associated with at least one DL transmission. The network entity 1202, in some aspects, may include means for transmitting the at least one DL transmission using the reduced CP length. The network entity 1202, in some aspects, may include means for transmitting, to a UE, a request for a suggested use of resources associated with transmitting a default CP having the default CP length that are not used to transmit a reduced CP having the reduced CP length. The network entity 1202, in some aspects, may include means for receiving, from the UE, a first indication of the suggested use of the resources. The network entity 1202, in some aspects, may include means for receiving, from a UE, channel information. The network entity 1202, in some aspects, may include means for generating, based on the channel information, a channel estimate for a channel between the network device and the UE. The network entity 1202, in some aspects, may include means for determining, based on the channel estimate, the reduced CP length. The network entity 1202, in some aspects, may include means for performing,129025-2594WO01Qualcomm Ref. No. 2500350WO 51 / 63based on the channel estimate, an equalization on the at least one DL transmission. The network entity 1202, in some aspects, may include means for receiving, from the UE, additional channel information. The network entity 1202, in some aspects, may include means for generating, based on the additional channel information, a second channel estimate for the channel between the network device and the UE. The network entity 1202, in some aspects, may include means for determining, based on the second channel estimate, an updated reduced CP length. The network entity 1202, in some aspects, may include means for performing, based on the second channel estimate, an additional equalization on an additional DL transmission. The network entity 1202, in some aspects, may include means for transmitting the additional DL transmission using the updated reduced CP length. The network entity 1202, in some aspects, may include means for receiving an indication of at least one of a mobility of the UE or of a synchronization uncertainty at the UE. The network entity 1202 may further include means for performing any of the aspects described in connection with the flowchart in FIG. 10, and / or performed by the base station in the communication flow of FIG.7. The means may be the CP shortening component 199 of the network entity 1202 configured to perform the functions recited by the means. As described supra, the network entity 1202 may include the TX processor 316, the RX processor 370, and the controller / processor 375. As such, in one configuration, the means may be the TX processor 316, the RX processor 370, and / or the controller / processor 375 configured to perform the functions recited by the means.

[0131] Various aspects relate generally to shortening the default CP length (e.g., a default CP length defined in a telecommunication standard) when implementing and / or using the Tx equalization such that the overall channel that the signal experiences has a much shorter support (e.g., is associated with less dispersion in time). Some aspects more specifically relate to a network configuring and / or indicating a shortened CP as a result of Tx equalization (e.g., implementing a channel inversion based on channel knowledge at the transmitter). Some aspects relate to different implementations and uses of the portion of a symbol associated with a standard CP length not used for transmitting the CP based on a shortened CP. In some examples, a wireless device may be configured to receive an indication of a reduced CP length associated with at least one DL transmission, receive the at least one DL transmission using the reduced CP length, and transmit a response to the at least one DL transmission. In some129025-2594WO01Qualcomm Ref. No. 2500350WO 52 / 63aspects, a network device may be configured to transmit an indication of a reduced CP length associated with at least one DL transmission and transmit the at least one DL transmission using the reduced CP length.

[0132] Particular aspects of the subject matter described in this disclosure can be implemented to realize one or more of the following potential advantages. In some examples, by indicating and / or using a shortened CP length, the described techniques can be used to improve wireless communications, improve spectral efficiency, and / or introduce additional functions (e.g., associated with using the remaining CP resources to increase throughput, add a TD pilot, enable a listening mode, etc.).

[0133] It is understood that the specific order or hierarchy of blocks in the processes / flowcharts disclosed is an illustration of example approaches. Based upon design preferences, it is understood that the specific order or hierarchy of blocks in the processes / flowcharts may be rearranged. Further, some blocks may be combined or omitted. The accompanying method claims present elements of the various blocks in a sample order, and are not limited to the specific order or hierarchy presented.

[0134] The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects. Thus, the claims are not limited to the aspects described herein, but are to be accorded the full scope consistent with the language claims. Reference to an element in the singular does not mean “one and only one” unless specifically so stated, but rather “one or more.” Terms such as “if,” “when,” and “while” do not imply an immediate temporal relationship or reaction. That is, these phrases, e.g., “when,” do not imply an immediate action in response to or during the occurrence of an action, but simply imply that if a condition is met then an action will occur, but without requiring a specific or immediate time constraint for the action to occur. The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any aspect described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects. Unless specifically stated otherwise, the term “some” refers to one or more. Combinations such as “at least one of A, B, or C,” “one or more of A, B, or C,” “at least one of A, B, and C,” “one or more of A, B, and C,” and “A, B, C, or any combination thereof’ include any combination of A, B, and / or C, and may include multiples of A,129025-2594WO01Qualcomm Ref. No. 2500350WO 53 / 63multiples of B, or multiples of C. Specifically, combinations such as “at least one of A, B, or C,” “one or more of A, B, or C,” “at least one of A, B, and C,” “one or more of A, B, and C,” and “A, B, C, or any combination thereof’ may be A only, B only, C only, A and B, A and C, B and C, or A and B and C, where any such combinations may contain one or more member or members of A, B, or C. Sets should be interpreted as a set of elements where the elements number one or more. Accordingly, for a set of X, X would include one or more elements. When at least one processor (i.e., a set of one or more processors P) is configured to perform a set of functions F, each processor of P may be configured to perform a subset S of F, where S £ F. Accordingly, each processor of the at least one processor may be configured to perform a particular subset of the set of functions, where the subset is the full set, a proper subset of the set, or an empty subset of the set. A processor may be referred to as processor circuitry. A memory / memory module may be referred to as memory circuitry. If a first apparatus receives data from or transmits data to a second apparatus, the data may be received / transmitted directly between the first and second apparatuses, or indirectly between the first and second apparatuses through a set of apparatuses. A device configured to “output” data or “provide” data, such as a transmission, signal, or message, may transmit the data, for example with a transceiver, or may send the data to a device that transmits the data. A device configured to “obtain” data, such as a transmission, signal, or message, may receive, for example with a transceiver, or may obtain the data from a device that receives the data. Information stored in a memory includes instructions and / or data. All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are encompassed by the claims. Moreover, nothing disclosed herein is dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. The words “module,” “mechanism,” “element,” “device,” and the like may not be a substitute for the word “means.” As such, no claim element is to be construed as a means plus function unless the element is expressly recited using the phrase “means for.”

[0135] As used herein, the phrase “based on” shall not be construed as a reference to a closed set of information, one or more conditions, one or more factors, or the like. In other words, the phrase “based on A” (where “A” may be information, a condition, a factor,129025-2594WO01Qualcomm Ref. No. 2500350WO 54 / 63or the like) shall be construed as “based at least on A” unless specifically recited differently.

[0136] The following aspects are illustrative only and may be combined with other aspects or teachings described herein, without limitation.

[0137] Aspect 1 is a method of wireless communication at a user equipment (UE), comprising: receiving configuration information for a reduced cyclic prefix (CP) length associated with at least one downlink (DL) transmission; receiving the at least one DL transmission using the reduced CP length; and transmitting a response to the at least one DL transmission.

[0138] Aspect 2 is the method of clause of any of clauses 1, wherein the reduced CP length is reduced relative to a default CP length associated with a numerology associated with the at least one DL transmission.

[0139] Aspect 3 is the method of clause of any of clauses 2, further comprising: receiving a request for a suggested use of resources associated with transmitting a default CP having the default CP length that are not used to transmit a reduced CP having the reduced CP length; and transmitting a first indication of the suggested use of the resources, wherein the configuration information for the reduced CP length comprises a second indication of a use of the resources.

[0140] Aspect 4 is the method of clause of any of clauses 3, wherein the use of the resources comprises one of: a first transmission of a time domain pilot signal, wherein the time domain pilot signal is preceded by a first guard band and is followed by a second guard band; a second transmission of data, wherein the second transmission of the data is preceded by the first guard band and is followed by the second guard band; or omitting, at a source of the at least one DL transmission, a transmission to allow for the UE to evaluate interference from at least one interference source.

[0141] Aspect 5 is the method of clause of any of clauses 4, wherein the use of the resources comprises one of the first transmission of the time domain pilot signal or the second transmission of the data, wherein the configuration information for the reduced CP length comprises a third indication of guard band resources associated with the first guard band and the second guard band.

[0142] Aspect 6 is the method of clause of any of clauses 4, wherein the use of the resources comprises omitting, at the source of the at least one DL transmission, the transmission, the method further comprising: evaluating the interference from the at least one129025-2594WO01Qualcomm Ref. No. 2500350WO 55 / 63interference source; and adjusting, based on the interference, a reception parameter at the UE.

[0143] Aspect 7 is the method of clause of any of clauses 1, wherein the at least one DL transmission is based on an equalization performed at a source of the at least one DL transmission, and the method further comprises: decoding, based on the reduced CP length, the at least one DL transmission using a decoding method consistent with a transmission based on the equalization performed at the source of the transmission.

[0144] Aspect 8 is the method of clause of any of clauses 7, wherein the indication of the reduced CP length is a first indication and the equalization performed at the source of the at least one DL transmission is a first equalization based on a first channel estimate, the method further comprising: transmitting an indication of a mobility of the UE; and receiving, after a time based on the indication of the mobility of the UE, an additional DL transmission based on a second equalization based on a second channel estimate performed at the source of the at least one DL transmission.

[0145] Aspect 9 is the method of clause of any of clauses 8, further comprising: receiving, after the time based on the second indication of the mobility of the UE, a third indication of an updated reduced CP length, wherein the updated reduced CP length is based on the second channel estimate.

[0146] Aspect 10 is the method of clause of any of clauses 8, wherein the first channel estimate is based on channel information transmitted from the UE, wherein the configuration information for the reduced CP length comprises an indication of a timing associated with transmitting channel information from the UE, and wherein the timing is based on the indicated mobility of the UE, the method further comprising: transmitting, based on the indicated timing, updated channel information, wherein the second channel estimate is based on the updated channel information.

[0147] Aspect 11 is the method of clause of any of clauses 1, further comprising: transmitting an additional indication of a synchronization uncertainty at the UE, wherein the reduced CP length is based on the indicated synchronization uncertainty.

[0148] Aspect 12 is a method of wireless communication at a network device, comprising:transmitting configuration information for a reduced cyclic prefix (CP) length associated with at least one downlink (DL) transmission; and transmitting the at least one DL transmission using the reduced CP length.129025-2594WO01Qualcomm Ref. No. 2500350WO 56 / 63

[0149] Aspect 13 is the method of clause of any of clauses 12, wherein the reduced CP length is reduced relative to a default CP length associated with a numerology associated with the at least one DL transmission.

[0150] Aspect 14 is the method of clause of any of clauses 13, further comprising:transmitting, to a user equipment (UE), a request for a suggested use of resources associated with transmitting a default CP having the default CP length that are not used to transmit a reduced CP having the reduced CP length; receiving, from the UE, a first indication of the suggested use of the resources, wherein the configuration information for the reduced CP length comprises a second indication of a use of the resources.

[0151] Aspect 15 is the method of clause of any of clauses 14, wherein the use of the resources comprises one of a first transmission of a time domain pilot signal, wherein the time domain pilot signal is preceded by a first guard band and is followed by a second guard band; a second transmission of data, wherein the second transmission of the data is preceded by the first guard band and is followed by the second guard band; or omitting a transmission to allow for the UE to evaluate interference from at least one interference source.

[0152] Aspect 16 is the method of clause of any of clauses 15, wherein the use of the resources comprises one of the first transmission of the time domain pilot signal or the second transmission of the data, wherein the configuration information for the reduced CP length comprises a third indication of guard band resources associated with the first guard band and the second guard band.

[0153] Aspect 17 is the method of clause of any of clauses 12, further comprising: receiving, from a user equipment (UE), channel information; generating, based on the channel information, a channel estimate for a channel between the network device and the UE; determining, based on the channel estimate, the reduced CP length; and performing, based on the channel estimate, an equalization on the at least one DL transmission.

[0154] Aspect 18 is the method of clause of any of clauses 17, wherein the configuration information for the reduced CP length is a first configuration information, the channel estimate is a first channel estimate, and the equalization on the at least one DL transmission is a first equalization based on the first channel estimate, the method further comprising: receiving, from the UE, additional channel information; generating, based on the additional channel information, a second channel estimate129025-2594WO01Qualcomm Ref. No. 2500350WO 57 / 63for the channel between the network device and the UE; determining, based on the second channel estimate, an updated reduced CP length; performing, based on the second channel estimate, an additional equalization on an additional DL transmission; and transmitting the additional DL transmission using the updated reduced CP length.

[0155] Aspect 19 is the method of clause of any of clauses 17, further comprising: receiving an indication of at least one of a mobility of the UE or of a synchronization uncertainty at the UE, wherein determining the reduced CP length further comprises determining the reduced CP length based on the indicated at least one of the mobility or the synchronization uncertainty.

[0156] Aspect 20 is an apparatus for wireless communication at a UE, comprising: at least one memory; and at least one processor coupled to the at least one memory, the at least one processor is configured to perform the method of any of aspects 1 to 11.

[0157] Aspect 21 is an apparatus for wireless communication at a UE, comprising means for performing each step in the method of any of aspects 1 to 11.

[0158] Aspect 22 is the apparatus of any of aspects 20 to 21, further comprising a transceiver configured to receive or to transmit in association with the method of any of aspects 1 to 11.

[0159] Aspect 23 is a computer-readable medium storing computer executable code at a UE, the code when executed by at least one processor causes the at least one processor to perform the method of any of aspects 1 to 11.

[0160] Aspect 24 is an apparatus for wireless communication at a network device, comprising: at least one memory; and at least one processor coupled to the at least one memory, the at least one processor is configured to perform the method of any of aspects 12 to 19.

[0161] Aspect 25 is an apparatus for wireless communication at a network device, comprising means for performing each step in the method of any of aspects 12 to 19.

[0162] Aspect 26 is the apparatus of any of aspects 24 to 25, further comprising a transceiver configured to receive or to transmit in association with the method of any of aspects 12 to 19.

[0163] Aspect 27 is a computer-readable medium storing computer executable code at a network device, the code when executed by at least one processor causes the at least one processor to perform the method of any of aspects 12 to 19.129025-2594WO01

Claims

Qualcomm Ref. No. 2500350WO 58 / 63CLAIMS WHAT IS CLAIMED IS:

1. An apparatus for wireless communication at a user equipment (UE), comprising: at least one memory; andat 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, the at least one processor is configured to:receive configuration information for a reduced cyclic prefix (CP) length associated with at least one downlink (DL) transmission;receive the at least one DL transmission using the reduced CP length; and transmit a response to the at least one DL transmission.

2. The apparatus of claim 1, wherein the reduced CP length is reduced relative to a default CP length associated with a numerology associated with the at least one DL transmission.

3. The apparatus of claim 2, further comprising a transceiver coupled to the at least one processor, the transceiver being configured to:receive a request for a suggested use of resources associated with transmitting a default CP having the default CP length that are not used to transmit a reduced CP having the reduced CP length; andtransmit a first indication of the suggested use of the resources, wherein the configuration information for the reduced CP length comprises a second indication of a use of the resources.

4. The apparatus of claim 3, wherein the use of the resources comprises one of:a first transmission of a time domain pilot signal, wherein the time domain pilot signal is preceded by a first guard band and is followed by a second guard band;a second transmission of data, wherein the second transmission of the data is preceded by the first guard band and is followed by the second guard band; or129025-2594WO01Qualcomm Ref. No. 2500350WO 59 / 63omitting, at a source of the at least one DL transmission, a transmission to allow for the UE to evaluate interference from at least one interference source.

5. The apparatus of claim 4, wherein the use of the resources comprises one of the first transmission of the time domain pilot signal or the second transmission of the data, wherein the configuration information for the reduced CP length comprises a third indication of guard band resources associated with the first guard band and the second guard band.

6. The apparatus of claim 4, wherein the use of the resources comprises omitting, at the source of the at least one DL transmission, the transmission, and wherein the at least one processor, individually or in any combination, is further configured to:evaluate the interference from the at least one interference source; and adjust, based on the interference, a reception parameter at the UE.

7. The apparatus of claim 1, wherein the at least one DL transmission is based on an equalization performed at a source of the at least one DL transmission, and wherein the at least one processor, individually or in any combination, is further configured to:decode, based on the reduced CP length, the at least one DL transmission using a decoding apparatus consistent with a transmission based on the equalization performed at the source of the transmission.

8. The apparatus of claim 7, wherein the equalization performed at the source of the at least one DL transmission is a first equalization based on a first channel estimate, and wherein the at least one processor, individually or in any combination, is further configured to:transmit an indication of a mobility of the UE; andreceive, after a time based on the indication of the mobility of the UE, an additional DL transmission based on a second equalization based on a second channel estimate performed at the source of the at least one DL transmission.129025-2594WO01Qualcomm Ref. No. 2500350WO 60 / 639. The apparatus of claim 8, wherein the at least one processor, individually or in any combination, is further configured to:receive, after the time based on the second indication of the mobility of the UE, a third indication of an updated reduced CP length, wherein the updated reduced CP length is based on the second channel estimate.

10. The apparatus of claim 8, wherein the first channel estimate is based on channel information transmitted from the UE, wherein the configuration information for the reduced CP length comprises an additional indication of a timing associated with transmitting the channel information from the UE, and wherein the timing is based on the indicated mobility of the UE, the apparatus further comprising:transmitting, based on the indicated timing, updated channel information, wherein the second channel estimate is based on the updated channel information.

11. The apparatus of claim 1, further wherein the at least one processor, individually or in any combination, is further configured to:transmit an additional indication of a synchronization uncertainty at the UE, wherein the reduced CP length is based on the indicated synchronization uncertainty.

12. A method of wireless communication at a user equipment (UE), comprising:receiving configuration information for a reduced cyclic prefix (CP) length associated with at least one downlink (DL) transmission;receiving the at least one DL transmission using the reduced CP length; and transmitting a response to the at least one DL transmission.

13. The method of claim 12, wherein the reduced CP length is reduced relative to a default CP length, associated with a numerology associated with the at least one DL transmission., the method further comprising:receiving a request for a suggested use of resources associated with transmitting a default CP having the default CP length that are not used to transmit a reduced CP having the reduced CP length; and129025-2594WO01Qualcomm Ref. No. 2500350WO 61 / 63transmitting a first indication of the suggested use of the resources, wherein the configuration information for the reduced CP length comprises a second indication of a use of the resources.

14. The method of claim 13, wherein the use of the resources comprises one ofa first transmission of a time domain pilot signal, wherein the time domain pilot signal is preceded by a first guard band and is followed by a second guard band;a second transmission of data, wherein the second transmission of the data is preceded by the first guard band and is followed by the second guard band; or omitting, at a source of the at least one DL transmission, a transmission to allow for the UE to evaluate interference from at least one interference source.

15. The method of claim 14, wherein the use of the resources comprises one of the first transmission of the time domain pilot signal or the second transmission of the data, wherein the configuration information for the reduced CP length comprises a third indication of guard band resources associated with the first guard band and the second guard band.

16. The method of claim 14, wherein the use of the resources comprises omitting, at the source of the at least one DL transmission, the transmission, the method further comprising:evaluating the interference from the at least one interference source; and adjusting, based on the interference, a reception parameter at the UE.

17. The method of claim 12, wherein the at least one DL transmission is based on an equalization performed at a source of the at least one DL transmission, and the method further comprises:decoding, based on the reduced CP length, the at least one DL transmission using a decoding method consistent with a transmission based on the equalization performed at the source of the transmission.129025-2594WO01Qualcomm Ref. No. 2500350WO 62 / 6318. The method of claim 17, wherein the equalization performed at the source of the at least one DL transmission is a first equalization based on a first channel estimate, the method further comprising:transmitting an indication of a mobility of the UE;receiving, after a time based on the indication of the mobility of the UE, an additional DL transmission based on a second equalization based on a second channel estimate performed at the source of the at least one DL transmission; and receiving, after the time based on the second indication of the mobility of the UE, a third indication of an updated reduced CP length, wherein the updated reduced CP length is based on the second channel estimate.

19. The method of claim 12, further comprising:transmitting an additional indication of a synchronization uncertainty at the UE, wherein the reduced CP length is based on the indicated synchronization uncertainty.

20. A computer-readable medium storing computer executable code at a user equipment (UE), the code when executed by at least one processor causes the at least one processor to:receive configuration information for a reduced cyclic prefix (CP) length associated with at least one downlink (DL) transmission;receive the at least one DL transmission using the reduced CP length; and transmit a response to the at least one DL transmission.129025-2594WO01

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