Frequency dependent residual sideband correction

Abstract

A network node may transmit a training signal for a UE on a plurality of subcarriers, the training signal being transmitted via a plurality of IQ modulators and a plurality of RF antenna panels; and receive feedback associated with the FDRSB based on the training signal. The network node may apply a FDRSB correction filter to at least one signal to be transmitted to the UE, and the FDRSB correction filter may be based on the feedback received from the UE. The training signal may include at least one tone transmitted on a first subset of subcarriers of the plurality of subcarriers, the first subset of subcarriers being configured to be symmetric with a second subset of subcarriers with respect to a center frequency of the plurality of subcarriers, and the second subset of subcarriers being free of the at least one tone of the training signal.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. patent application serial number 17 / 930,403, filed on September 7, 2022, entitled “FREQUENCY DEPENDENT RESIDUALSIDE BAND CORRECTION,” which is expressly incorporated herein by reference in its entirety. Technical Field

[0003] The present disclosure relates generally to communication systems, and more particularly to wireless communications including frequency dependent vestigial sideband (FDRSB) correction. Background Art

[0004] Wireless communication systems are widely deployed to provide a variety of telecommunication services, such as telephony, video, data, messaging, and broadcast. Typical wireless communication systems may employ multiple access technologies capable of supporting communication with multiple users by sharing available system resources. Examples of such multiple access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single carrier frequency division multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems.

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

[0006] A simplified summary of one or more aspects is presented below to provide a basic understanding of these aspects. This summary is not an extensive review of all contemplated aspects. This summary neither identifies the key or important elements of all aspects, nor describes the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to a more detailed description presented later.

[0007] In one aspect of the present disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus includes a network node configured to: send a training signal for a user equipment (UE) on multiple subcarriers, the training signal being sent via multiple in-phase (I) and quadrature (Q) (IQ) modulators and multiple RF antenna panels; receive feedback associated with a frequency domain residual sideband (FDRSB) based on the training signal; and apply an FDRSB correction filter to at least one signal to be sent to the UE, the FDRSB correction filter being based on the feedback received from the UE.

[0008] In another aspect of the present disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus includes a user equipment (UE) configured to: receive a training signal from a network node on multiple subcarriers from multiple IQ modulators and multiple RF antenna panels; and send feedback associated with FDRSB to the network node based on the training signal, wherein at least one frequency tone of the training signal is received on a first subcarrier subset of the multiple subcarriers, the first subcarrier subset is configured to be symmetric with a second subcarrier subset relative to a center frequency of the multiple subcarriers, and the second subcarrier subset is free of the at least one frequency tone of the training signal.

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

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

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

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

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

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

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

[0016] Figure 4 An example of complex frequency-domain vestigial sideband (FDRSB) estimation and cancellation is illustrated.

[0017] Figure 5A is an example of a training signal for estimating a composite FDRSB.

[0018] Figure 5B is an example of an equalized signal of a training signal measured at a UE.

[0019] Figure 6 A block diagram of a composite FDRSB correction is illustrated.

[0020] Figure 7 is an example of a training signal for estimating a composite FDRSB.

[0021] Figure 8 is a call flow diagram of a method of wireless communication.

[0022] Fig. 9 is a flow chart of a method of wireless communication.

[0023] Fig.10 is a flow chart of a method of wireless communication.

[0024] Fig.11 is a flow chart of a method of wireless communication.

[0025] Fig.12 is a flow chart of a method of wireless communication.

[0026] Fig.13 is a diagram illustrating an example of a hardware implementation for an example apparatus and / or UE.

[0027] Fig.14 is a diagram illustrating an example of a hardware implementation for an example network entity. DETAILED DESCRIPTION

[0028] When a network node (e.g., a base station such as a gNB) is configured with multiple IQ modulators, each IQ modulator may experience IQ mismatch (e.g., FDRSB impairment component) and FDRSB impairment. Eliminating IQ mismatch or FDRSB improves link performance. Estimation of FDRSB may increase the complexity of the network node, for example, the complexity increases with the number of antennas and IQ modulators of the network node. Various aspects of the present disclosure provide more efficient FDRSB correction by sending a training signal for a user equipment (UE) by the network node to measure or estimate a composite FDRSB impairment component. The UE provides information to the network node based on the estimate, which enables reducing the complexity at the network node to eliminate FDRSB and improve the link performance between the network node and the UE.

[0029] The specific embodiments described below in conjunction with the accompanying drawings are descriptions of various configurations and do not represent the only configurations in which the concepts described herein can be practiced. In order to provide a thorough understanding of the various concepts, the specific embodiments include specific details. However, these concepts can be practiced without these specific details. In some cases, well-known structures and components are shown in block diagram form to avoid blurring such concepts.

[0030] 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 on the specific application and the design constraints imposed on the overall system.

[0031] As an example, an element, or any part of an element, or any combination of elements, may be implemented as a "processing system" including one or more processors. Examples of processors include microprocessors, microcontrollers, graphics processing units (GPUs), central processing units (CPUs), application processors, digital signal processors (DSPs), reduced instruction set computing (RISC) processors, systems on chip (SoCs), baseband processors, field programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gated logic components, discrete hardware circuits, and other suitable hardware configured to perform various functionalities described throughout the present disclosure. One or more processors in a processing system may execute software. Whether referred to as software, firmware, middleware, microcode, hardware description language, or other terms, software should be broadly interpreted as meaning instructions, instruction sets, codes, code segments, program codes, programs, subroutines, software components, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, or any combination thereof.

[0032] Thus, in one or more example aspects, specific implementations and / or use cases, the described functionality may be implemented in hardware, software, or any combination thereof. If implemented in software, the functionality may be stored or encoded as one or more instructions or codes on a computer-readable medium. Computer-readable media include computer storage media. Storage media may be any available media that can be accessed by a computer. As an example, such computer-readable media may include random access memory (RAM), read-only memory (ROM), electrically erasable programmable ROM (EEPROM), optical disk storage, magnetic disk storage, other magnetic storage devices, combinations of these types of computer-readable media, or any other 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.

[0033] Although various aspects, specific implementations and / or use cases are described in this application by the illustration of some examples, additional or different aspects, specific implementations and use cases may be generated in many different arrangements and scenarios. The various aspects, specific implementations and / or use cases described herein can be implemented across many different platform types, devices, systems, shapes, sizes and packaging arrangements. For example, various aspects, specific implementations and / or use cases can be generated via integrated chip specific implementations and other devices based on non-module components (e.g., end-user devices, vehicles, communication equipment, computing equipment, industrial equipment, retail / purchase equipment, medical equipment, devices that enable artificial intelligence (AI), etc.). Although some examples may or may not be specifically for use cases or applications, the described examples may have a wide range of applicability. Various aspects, specific implementations and / or use cases can be in the range from chip-level or modular components to non-modular, non-chip-level specific implementations, and further to the range of aggregated, distributed or original equipment manufacturer (OEM) equipment or systems in conjunction with one or more technologies herein. In some practical environments, the equipment in conjunction with the various aspects and features described may also include additional components and features for implementing and practicing the claimed and described aspects. For example, the transmission and reception of wireless signals necessarily include multiple components for analog and digital purposes (e.g., hardware components including antennas, RF chains, power amplifiers, modulators, buffers, processors, interleavers, adders / summers, etc.) The various techniques described herein can be practiced in a wide variety of devices of various sizes, shapes, and configurations, chip-level components, systems, distributed arrangements, aggregated or disaggregated components, end-user devices, etc.

[0034] The deployment of a communication system (such as a 5G NR system) can be arranged with various components or components in a variety of ways. In a 5G NR system or network, a network node, a network entity, a mobility element of a network, a radio access network (RAN) node, a core network node, a network element or a network equipment (such as a base station (BS), or one or more units (or one or more components) that perform base station functionality) can be implemented in an aggregated architecture or a decomposed architecture. For example, a BS (such as a Node B (NB), an evolved NB (eNB), an NR BS, a 5G NB, an access point (AP), a transmit receive point (TRP) or a cell, etc.) can be implemented as an aggregated base station (also referred to as an independent BS or a monolithic BS) or a decomposed base station.

[0035] A converged base station may be configured to utilize a radio protocol stack physically or logically integrated within a single RAN node. A decomposed base station may be configured to utilize a protocol stack physically or logically distributed between 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 in one or more other RAN nodes. A DU may be implemented to communicate with one or more RUs. Each of a CU, a DU, and a RU may be implemented as a virtual unit, i.e., a virtual central unit (VCU), a virtual distributed unit (VDU), or a virtual radio unit (VRU).

[0036] Base station operation or network design may take into account the aggregated nature of base station functionality. For example, a disaggregated base station may be used in an integrated access backhaul (IAB) network, an open radio access network (O-RAN (network configuration such as that initiated by the O-RAN Alliance)), or a virtualized radio access network (vRAN, also known as a cloud radio access network (C-RAN)). Decomposition may include distributing functionality across two or more units at various physical locations, as well as virtually distributing functionality of at least one unit, which may enable flexibility in network design. Individual units of a disaggregated base station or disaggregated RAN architecture may be configured for wired or wireless communication with at least one other unit.

[0037] Figure 11 is a diagram 100 illustrating an example of a wireless communication system and an access network. The illustrated wireless communication system includes a disaggregated base station architecture. The disaggregated base station architecture may include one or more CUs 110 that may communicate directly with a core network 120 via a backhaul link, or indirectly with the core network 120 through one or more disaggregated base station units, such as a near real-time (near RT) RAN intelligent controller (RIC) 125 via an E2 link, or a non-real-time (non-RT) RIC 115 associated with a service management and orchestration (SMO) framework 105, or both. The CU 110 may communicate with one or more DUs 130 via corresponding midhaul links, such as an F1 interface. The DU 130 may communicate with one or more RUs 140 via corresponding fronthaul links. The RU 140 may communicate with corresponding UEs 104 via one or more radio frequency (RF) access links. In some implementations, a UE 104 may be served simultaneously by multiple RUs 140.

[0038] Each of these units (i.e., CU 110, DU 130, RU 140, and near-RT RIC 125, non-RT RIC 115, and SMO framework 105) may include or be coupled to one or more interfaces configured to receive or send signals, data, or information (collectively, signals) via a wired or wireless transmission medium. Each of these units or an associated processor or controller that provides instructions to the communication interface of these units may be configured to communicate with one or more of the other units via a transmission medium. For example, these units may include a wired interface configured to receive signals or send signals to one or more of the other units via a wired transmission medium. Additionally, these units may include a wireless interface that may include a receiver, transmitter, or transceiver (such as an RF transceiver) configured to receive and / or send signals to one or more of the other units via a wireless transmission medium.

[0039] In some aspects, CU 110 may host one or more higher layer control functions. Such control functions may include radio resource control (RRC), packet data convergence protocol (PDCP), service data adaptation protocol (SDAP), etc. Each control function may be implemented using an interface that is configured to communicate signals with other control functions hosted by CU 110. 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 specific implementations, CU 110 may be logically split into one or more CU-UP units and one or more CU-CP units. When implemented in an O-RAN configuration, the CU-UP unit may communicate bidirectionally with the CU-CP unit via an interface (such as an E1 interface). As needed, CU 110 may be implemented to communicate with DU 130 for network control and signaling.

[0040] DU 130 may correspond to a logical unit that includes one or more base station functions for controlling the operation of one or more RUs 140. In some aspects, 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 and demodulation, etc.) at least in part according to a functional split such as those defined by 3GPP. In some aspects, DU 130 may further host one or more low PHY layers. Each layer (or module) may be implemented using an interface that is configured to communicate signals with other layers (and modules) hosted by DU 130 or with control functions hosted by CU 110.

[0041] The lower layer functionality may be implemented by one or more RUs 140. In some deployments, the RU 140 controlled by the 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, etc.), or both, based at least in part on functional splitting (such as lower layer functional splitting). In such an architecture, the RU 140 may be implemented to handle over-the-air (OTA) communications with one or more UEs 104. In some specific implementations, real-time and non-real-time aspects of control plane communications and user plane communications with the RU 140 may be controlled by the corresponding DU 130. In some scenarios, this configuration may enable the DU 130 and CU 110 to be implemented in a cloud-based RAN architecture (such as a vRAN architecture).

[0042] The SMO framework 105 may be configured to support RAN deployment and provisioning of non-virtualized network elements 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, which may be managed via an operation and maintenance interface (such as an O1 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 lifecycle management (such as instantiating virtualized network elements) via a cloud computing platform interface (such as an O2 interface). Such virtualized network elements may include, but are not limited to, CU 110, DU 130, RU 140, and near-RT RIC 125. In some specific implementations, the SMO framework 105 may communicate with hardware aspects of the 4G RAN (such as an open eNB (O-eNB) 111) via the O1 interface. Additionally, in some specific implementations, the SMO framework 105 may communicate directly with one or more RUs 140 via the O1 interface. The SMO framework 105 may also include a non-RT RIC 115 configured to support the functionality of the SMO framework 105 .

[0043] The non-RT RIC 115 may be configured to include logic functions that enable non-real-time control and optimization of RAN elements and resources, artificial intelligence (AI) / machine learning (ML) (AI / ML) workflows including model training and updating, or policy-based guidance of applications / features in the near-RT RIC 125. The non-RT RIC 115 may be coupled to or in communication with the near-RT RIC 125 (such as via an A1 interface). The near-RT RIC 125 may be configured to include logic functions that enable near-real-time control and optimization of RAN elements and resources via data collection and actions through an interface (such as via an E2 interface) that connects one or more CUs 110, one or more DUs 130, or both, and the O-eNB with the near-RT RIC 125.

[0044] In some implementations, in order to generate an AI / ML model to be deployed in the near-RT RIC 125, the non-RT RIC 115 may receive parameters or external enrichment information from an external server. Such information may be utilized by the near-RT RIC 125 and may be received from a non-network data source or from a network function at the SMO framework 105 or the non-RT RIC 115. In some examples, the non-RT RIC 115 or the near-RT RIC 125 may be configured to tune RAN behavior or performance. For example, the non-RT RIC 115 may monitor long-term trends and patterns of performance and employ AI / ML models to perform corrective actions through the SMO framework 105 (such as via reconfiguration of O1) or via the creation of RAN management policies (such as A1 policies).

[0045] At least one of the CU 110, the DU 130, and the RU 140 may be referred to as a base station 102. Therefore, the base station 102 may include one or more of the CU 110, the DU 130, and the RU 140 (each component is indicated by a dotted line to indicate that each component may be included in the base station 102 or may not be included in the base station). The base station 102 provides an access point to the core network 120 for the UE 104. The base station 102 may include a macro cell (a high-power cellular base station) and / or a small cell (a low-power cellular base station). Small cells include femto cells, pico cells, and micro cells. A network including both small cells and macro cells may be referred to as a heterogeneous network. A heterogeneous network may also include a home evolved Node B (eNB) (HeNB), which may provide services to a restricted group referred to as a closed subscriber group (CSG). The communication link between RU 140 and UE 104 may include uplink (UL) (also known as reverse link) transmission from UE 104 to RU 140 and / or downlink (DL) (also known as forward link) transmission from RU 140 to UE 104. The communication link may use multiple-input multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming and / or transmit diversity. The communication link may be through one or more carriers. For each carrier allocated in a carrier aggregation of up to Yx MHz (x component carriers) for transmission in each direction, the base station 102 / UE 104 may use a spectrum of up to Y MHz (e.g., 5MHz, 10MHz, 15MHz, 20MHz, 100MHz, 400MHz, etc.) bandwidth. These carriers may or may not be adjacent to each other. The allocation of carriers may be asymmetric with respect to DL and UL (e.g., more or fewer carriers may be allocated for DL ​​compared to UL). Component carriers may include a primary component carrier and one or more secondary component carriers. The primary component carrier may be referred to as a primary cell (PCell) and the secondary component carrier may be referred to as a secondary cell (SCell).

[0046] Some UEs 104 may communicate with each other using a device-to-device (D2D) communication link 158. The D2D communication link 158 may use DL / UL 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). The D2D communication may be through a variety of wireless D2D communication systems, such as, for example, Bluetooth, Wi-Fi based on the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard, LTE, or NR.

[0047] The wireless communication system may also include a Wi-Fi AP 150 that communicates with a UE 104 (also referred to as a Wi-Fi station (STA)) via a communication link 154, for example, in a 5 GHz unlicensed spectrum, etc. When communicating in an unlicensed spectrum, the UE 104 / AP 150 may perform a clear channel assessment (CCA) to determine whether a channel is available prior to communication.

[0048] The electromagnetic spectrum is typically subdivided into various categories, bands, channels, etc. based on frequency / wavelength. In 5G NR, two initial operating bands have been identified as frequency range designations FR1 (410 MHz-7.125 GHz) and FR2 (24.25 GHz-52.6 GHz). Although a portion of FR1 is greater than 6 GHz, FR1 is often referred to (interchangeably) as the "sub-6 GHz" band in various documents and articles. A similar naming issue sometimes occurs with respect to FR2, which is often (interchangeably) referred to as the "millimeter wave" band in documents and articles, although different from the extremely high frequency (EHF) band (30 GHz-300 GHz) identified as the "millimeter wave" band by the International Telecommunication Union (ITU).

[0049] Frequencies between FR1 and FR2 are generally referred to as mid-band frequencies. Recent 5G NR research has identified the operating bands for these mid-band frequencies as frequency range designation FR3 (7.125GHz-24.25GHz). The bands falling within FR3 can inherit FR1 characteristics and / or FR2 characteristics, so the features of FR1 and / or FR2 can be effectively extended to mid-band frequencies. In addition, higher frequency bands are currently being explored to extend 5G NR operations to more than 52.6GHz. For example, three higher operating bands have been identified as frequency range designations FR2-2 (52.6GHz-71GHz), FR4 (71GHz-114.25GHz) and FR5 (114.25GHz-300GHz). Each of these higher frequency bands falls within the EHF band.

[0050] In view of the above, unless otherwise specified, if the term "6 GHz or less" is used herein, it may broadly refer to frequencies that may be less than 6 GHz, may be within FR1, or may include mid-band frequencies. In addition, unless otherwise specified, if the term "millimeter wave" is used herein, it may broadly refer to frequencies that may include mid-band frequencies, may be within FR2, FR4, FR2-2, and / or FR5, or may be within the EHF band.

[0051] The base station 102 and the UE 104 may each include multiple antennas (such as antenna elements, antenna panels, and / or antenna arrays) to facilitate beamforming. The base station 102 may send 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 send a beamformed signal 184 to the base station 102 in one or more transmit directions. The base station 102 may receive the beamformed signal from the UE 104 in one or more receive directions. The base station 102 / UE 104 may perform beam training to determine the best receive direction and transmit direction for each of the base station 102 / UE 104. The transmit direction and receive direction of the base station 102 may be the same or different. The transmit direction and receive direction of the UE 104 may be the same or different.

[0052] The base station 102 may include and / or be referred to as a gNB, a Node B, an eNB, an access point, a base transceiver station, a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS), an extended service set (ESS), a transmit receive point (TRP), a network node, a network entity, a network equipment, or some other suitable term. The base station 102 may 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 a RU, or as a decomposed base station including one or more of a CU, a DU, and / or a RU. A set of base stations that may include decomposed base stations and / or aggregated base stations may be referred to as a next generation (NG) RAN (NG-RAN).

[0053] 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. AMF 161 is a control node that handles signaling between UE 104 and core network 120. AMF 161 supports registration management, connection management, mobility management, and other functions. SMF 162 supports session management and other functions. UPF 163 supports packet routing, packet forwarding, and other functions. UDM 164 supports the generation of authentication and key agreement (AKA) credentials, user identity handling, access authorization, and subscription management. One or more location servers 168 are illustrated as including a gateway mobile location center (GMLC) 165 and a location management function (LMF) 166. However, in general, 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, LMF 166, position determination entity (PDE), serving mobile location center (SMLC), mobile positioning center (MPC), etc. GMLC 165 and LMF 166 support UE location services. GMLC 165 provides an interface for clients / applications (e.g., emergency services) to access UE positioning information. LMF 166 receives measurement and assistance information from NG-RAN and UE 104 via AMF 161 to calculate the location of UE 104. NG-RAN may determine the location of UE 104 using one or more positioning methods. Positioning UE 104 may involve signal measurements, position estimation, and optional speed calculation based on these measurements. Signal measurements may be performed by UE 104 and / or serving base station 102. The measured signals may be based on a satellite positioning system (SPS) 170 (e.g., one or more of a global navigation satellite system (GNSS), a global positioning system (GPS), a non-terrestrial network (NTN), or other satellite positioning / location systems), LTE signals, wireless local area network (WLAN) signals, Bluetooth signals, a terrestrial beacon system (TBS), sensor-based information (e.g., an atmospheric pressure sensor, a motion sensor), an NR enhanced cell ID (NR E-CID) method, NR signals (e.g., multi-round trip time (multi-RTT), DL angle of departure (DL-AoD), DL time difference of arrival (DL-TDOA), UL time difference of arrival (UL-TDOA), and UL angle of arrival (UL-AoA) positioning), and / or one or more of other systems / signals / sensors.

[0054] Examples of UE 104 include cellular phones, smart phones, session initiation protocol (SIP) phones, laptops, personal digital assistants (PDAs), satellite radios, global positioning systems, multimedia devices, video devices, digital audio players (e.g., MP3 players), cameras, game consoles, tablet computers, smart devices, wearable devices, vehicles, electric meters, gas pumps, large or small kitchen appliances, healthcare equipment, implants, sensors / actuators, displays, or any other similarly functional devices. Some of the UEs 104 may be referred to as IoT devices (e.g., parking meters, gas pumps, toasters, vehicles, heart monitors, etc.). UE 104 may also be referred to as stations, mobile stations, subscriber stations, mobile units, subscriber units, wireless units, remote units, mobile devices, wireless devices, wireless communication devices, remote devices, mobile subscriber stations, access terminals, mobile terminals, wireless terminals, remote terminals, mobile phones, user agents, mobile clients, clients, or some other suitable terminology. In some scenarios, the term UE may also be applied to one or more supporting devices, such as in a device cluster arrangement. One or more of these devices may access the network collectively and / or individually.

[0055] See again Figure 1 In some aspects, the UE 104 may include an FDRSB estimation component 198 configured to: receive a training signal from a network node on a plurality of subcarriers from a plurality of IQ modulators and a plurality of RF antenna panels; and send feedback associated with FDRSB to the network node based on the training signal, wherein at least one frequency tone of the training signal is received on a first subset of subcarriers in the plurality of subcarriers, the first subset of subcarriers being configured to be symmetric with a second subset of subcarriers relative to a center frequency of the plurality of subcarriers, and the second subset of subcarriers being devoid of the at least one frequency tone of the training signal. In some aspects, the base station 102 may include an FDRSB correction component 199 configured to: send a training signal for the UE on a plurality of subcarriers, the training signal being sent via a plurality of IQ modulators and a plurality of RF antenna panels; receive feedback associated with FDRSB based on the training signal; and apply an FDRSB correction filter to at least one signal to be sent to the UE, the FDRSB correction filter being based on the feedback received from the UE. Although the following description may focus on 5G NR, the concepts described herein may be applicable to other similar areas such as LTE, LTE-A, CDMA, GSM, and other wireless technologies.

[0056] Figure 2A FIG200 is a diagram illustrating an example of a first subframe within a 5G NR frame structure. Figure 2BFIG230 is a diagram illustrating an example of DL channels within a 5G NR subframe. Figure 2C FIG250 is a diagram illustrating an example of a second subframe within a 5G NR frame structure. Figure 2D FIG280 is a diagram illustrating an example of UL channels within a 5G NR subframe. The 5G NR frame structure may be frequency division duplex (FDD), where for a particular set of subcarriers (carrier system bandwidth), subframes within that subcarrier set are dedicated to either DL or UL, or may be time division duplex (TDD), where for a particular set of subcarriers (carrier system bandwidth), subframes within that subcarrier set are dedicated to both DL and UL. Figure 2A , Figure 2C In the example provided, the 5G NR frame structure is assumed to be TDD, where subframe 4 is configured with slot format 28 (most of which are DL), where D is DL, U is UL, and F is flexible between DL / UL, and subframe 3 is configured with slot format 1 (all of which are UL). Although subframes 3 and 4 are shown as having slot formats 1 and 28, respectively, any particular subframe may be configured with any of the various available slot formats 0-61. Slot formats 0 and 1 are full DL and full UL, respectively. Other slot formats 2-61 include a mix of DL, UL and flexible symbols. The UE is configured with the slot format through the received slot format indicator (SFI) (dynamically configured through DL control information (DCI) or semi-statically / statically configured through radio resource control (RRC) signaling). Note that the following description also applies to the 5G NR frame structure as TDD.

[0057] FIG. 2A to FIG. 2DThe frame structure is illustrated, and various aspects of the present disclosure may be applicable to other wireless communication technologies that may have different frame structures and / or different channels. A frame (10ms) may be divided into 10 subframes of equal size (1ms). Each subframe may include one or more time slots. A subframe may also include a microslot, which may include 7, 4, or 2 symbols. Each time slot may include 14 or 12 symbols, depending on whether the cyclic prefix (CP) is normal or extended. For a normal CP, each time slot may include 14 symbols, and for an extended CP, each time slot may include 12 symbols. The symbol on the DL may be a CP orthogonal frequency division multiplexing (OFDM) (CP-OFDM) symbol. The symbol on the UL may be a CP-OFDM symbol (for high throughput scenarios) or a discrete Fourier transform (DFT) extended OFDM (DFT-s-OFDM) symbol (also known as a single carrier frequency division multiple access (SC-FDMA) symbol) (for power-limited scenarios; limited to single-stream transmission). The number of slots within a subframe is based on the CP and the parameter set. The parameter set defines the subcarrier spacing (SCS) and effectively defines the symbol length / duration, which is equal to 1 / SCS (see Figure 1 ).

[0058]

[0059] Table 1: Parameter set, SCS and CP

[0060] For normal CP (14 symbols / slot), different parameter sets μ0 to 4 allow 1, 2, 4, 8, and 16 slots per subframe, respectively. For extended CP, parameter set 2 allows 4 slots per subframe. Thus, for normal CP and parameter set μ, there are 14 symbols / slot and 2 μ timeslots / subframe. The subcarrier spacing can be equal to 2 μ *15kHz, where μ is parameter set 0 to 4. Therefore, the subcarrier spacing for parameter set μ=0 is 15kHz, and the subcarrier spacing for parameter set μ=4 is 240kHz. The symbol length / duration is inversely related to the subcarrier spacing. FIG. 2A to FIG. 2D An example of a parameter set μ=2 with a normal CP of 14 symbols per slot and 4 slots per subframe is provided. The slot duration is 0.25 ms, the subcarrier spacing is 60 kHz, and the symbol duration is about 16.67 μs. Within a frame set, there may be one or more different bandwidth parts (BWPs) that are frequency-division multiplexed (see Figure 2B ). Each BWP may have a specific parameter set and CP (normal or extended).

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

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

[0063] Figure 2B Examples of various DL channels within a subframe of a frame are illustrated. A 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 a BWP may be referred to as a control resource set (CORESET). The UE is configured to monitor PDCCH candidates in a PDCCH search space (e.g., a common search space, a UE-specific search space) during a PDCCH monitoring opportunity on a CORESET, wherein the PDCCH candidates have different DCI formats and different aggregation levels. Additional BWPs may be located at higher and / or lower frequencies on the channel bandwidth. A primary synchronization signal (PSS) may be within symbol 2 of a particular subframe of a frame. The PSS is used by UE 104 to determine subframe / symbol timing and physical layer identification. A secondary synchronization signal (SSS) may be within symbol 4 of a particular subframe of a frame. The SSS is used by the UE to determine the physical layer cell identity group number and the radio frame timing. Based on the physical layer identity and the physical layer cell identity group number, the UE can determine the physical cell identifier (PCI). Based on the PCI, the UE can determine the location of the DM-RS. The physical broadcast channel (PBCH) carrying the master information block (MIB) can be logically grouped with the PSS and SSS to form a synchronization signal (SS) / PBCH block (also referred to as an SS block (SSB)). The MIB provides the system frame number (SFN) and the number of RBs in the system bandwidth. The physical downlink shared channel (PDSCH) carries user data, broadcast system information such as system information blocks (SIBs) that are not sent via the PBCH, and paging messages.

[0064] like Figure 2CAs illustrated, some of the REs carry DM-RS (indicated as R for a particular configuration, but other DM-RS configurations are possible) for channel estimation at the base station. The UE may send a DM-RS for a physical uplink control channel (PUCCH) and a DM-RS for a physical uplink shared channel (PUSCH). The PUSCH DM-RS may be sent in the first or first two symbols of the PUSCH. Depending on whether a short PUCCH or a long PUCCH is sent and depending on the specific PUCCH format used, the PUCCH DM-RS may be sent in different configurations. The UE may send a sounding reference signal (SRS). The SRS may be sent in the last symbol of a subframe. The SRS may have a comb structure, and the UE may send the SRS on one of the teeth of the comb. The SRS may be used by the base station for channel quality estimation to achieve frequency-dependent scheduling of the UL.

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

[0066] Figure 3375. The Controller / Processor 375 is a block diagram of a base station 310 in an access network communicating with a UE 350. In the DL, Internet Protocol (IP) packets may be provided to a controller / processor 375. The controller / processor 375 implements layer 3 and layer 2 functionality. Layer 3 includes a radio resource control (RRC) layer, and layer 2 includes a service data adaptation protocol (SDAP) layer, a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, and a medium access control (MAC) layer. The controller / processor 375 provides RRC layer functionality associated with broadcasting of system information (e.g., MIB, SIB), RRC connection control (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release), inter-radio access technology (RAT) mobility, and measurement configuration for UE measurement reporting; PDCP layer functionality associated with header compression / decompression, security (encryption, decryption, integrity protection, integrity verification), and handover support functions; RLC layer functionality associated with delivery 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 receive (RX) processor 370 implement layer 1 functionality associated with various signal processing functions. Layer 1 (which includes the physical (PHY) layer) may include error detection on the transport channel, forward error correction (FEC) coding / decoding of the transport channel, interleaving, rate matching, mapping onto the physical channel, modulation / demodulation of the physical channel, and MIMO antenna processing. The TX processor 316 handles the mapping to the signal constellation based on various modulation schemes (e.g., binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), M-order phase shift keying (M-PSK), M-order quadrature amplitude modulation (M-QAM)). The coded and modulated symbols may then be separated 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 pre-coded to generate multiple spatial streams. Channel estimates from a channel estimator 374 may be used to determine the coding and modulation schemes, as well as for spatial processing. Channel estimates may be derived from reference signals and / or channel state feedback sent by the UE 350. Each spatial stream may then be provided to a different antenna 320 via a separate transmitter 318Tx. Each transmitter 318Tx may modulate a radio frequency (RF) carrier for transmission using a corresponding spatial stream.

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

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

[0070] Similar to the functionality described in conjunction with DL transmissions performed by the base station 310, the controller / processor 359 provides RRC layer functionality associated with system information (e.g., MIB, SIB) acquisition, RRC connection, and measurement reporting; PDCP layer functionality associated with header compression / decompression and security (encryption, decryption, integrity protection, integrity verification); RLC layer functionality associated with delivery of upper layer PDUs, error correction through ARQ, concatenation, segmentation and reassembly of RLC SDUs, resegmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer 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 the channel estimator 358 based on a reference signal or feedback sent by the base station 310 may be used by the TX processor 368 to select the appropriate coding and modulation schemes and to facilitate spatial processing. The spatial streams generated by the TX processor 368 may be provided to different antennas 352 via separate transmitters 354Tx. Each transmitter 354Tx may modulate an RF carrier with a corresponding spatial stream for transmission.

[0072] UL transmissions are processed at the base station 310 in a manner similar to that described in conjunction with the receiver functionality 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 the RX processor 370.

[0073] The controller / processor 375 may be associated with a memory 376 that stores program codes and data. The memory 376 may be referred to as a computer readable medium. In the UL, the controller / processor 375 provides demultiplexing between transport channels and logical channels, packet reassembly, decryption, header decompression, control signal processing to recover IP packets. The controller / processor 375 is also responsible for error detection using ACK and / or NACK protocols 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 combine Figure 1 The FDRSB estimation component 198 performs various aspects. At least one of the TX processor 316, the RX processor 370, and the controller / processor 375 may be configured to combine Figure 1 The FDRSB correction component 199 performs various aspects.

[0075] In some aspects, a network node (e.g., a base station such as a gNB) may use one or more antenna panels or a remote radio head (RRH) including multiple antennas for beamforming procedures. Figure 1 182 and 184 in . Multiple antennas may be associated with multiple in-phase (I) and quadrature (Q) (IQ) modulators. Multiple IQ modulators may be used to modulate signals to be sent to a UE, and multiple antennas may be used to send IQ modulated signals to the UE.

[0076] In some aspects, a frequency domain residual sideband (FDRSB) impairment may be one of the physical layer (PHY) impairments that may be caused by IQ mismatch of multiple IQ modulators. That is, the IQ mismatch, which may be referred to as FDRSB, may be an inherent impairment of the IQ modulator. Here, the IQ mismatch may be a frequency-dependent impairment, for example, varying based on the frequency of the signal. If FDRSB is not eliminated or unprocessed, FDRSB may cause noise and limit the link performance between the network node and the UE.

[0077] The network node may use many antennas connected to multiple IQ modulators (e.g., massive MIMO). In one aspect, the network node may be configured to estimate and mitigate FDRSB. The network node may be configured with dedicated hardware for FDRSB estimation and mitigation, which may include an RF feedback chain for each of the multiple IQ modulators. The dedicated hardware may be configured to sample a signal (e.g., an analog-to-digital converter (ADC)) and run an FDRSB estimation. Including dedicated hardware may increase the complexity and cost of the network node.

[0078] Furthermore, the network node may not estimate the composite FDRSB because the network node is not aware of the channel transfer function observed at the UE. That is, the network node may be configured to estimate and mitigate FDRSB, but may not support estimation of the composite FDRSB measured at the UE.

[0079] The various aspects presented herein provide an improved procedure in which a network node transmits a training signal to a UE, and the UE estimates a composite FDRSB correction of all Tx chains and provides information to the network node. The UE can send feedback of the FDRSB correction to the network node over the air (OTA). Using training signals can significantly reduce the cost and complexity of the network node to improve link performance through FDRSB suppression.

[0080] In some aspects, the training signal may be configured for network nodes and UEs to use for estimation of composite FDRSB. The estimation may be run on the UE side. That is, the network node and UE may be configured to use the training signal to estimate and eliminate the composite FDRSB. In some examples, the estimation of the composite FDRSB using the training signal may have low complexity and relatively fast processing speed.

[0081] In one aspect, the training signal used by the UE and the network node to estimate and cancel the Tx FDRSB of the network node can be configured to reduce the complexity of the procedure for the UE to estimate the FDRSB of the network node. That is, the training signal can be designed to capture the entire wideband FDRSB and implement a relatively simple OTA feedback process of the FDRSB correction filter to the network node.

[0082] On the other hand, the network node may inform the UE of the time slots in which the training symbols may be sent. The term "training signal" is merely an example of a name that may be used to refer to a signal used for FDRSB estimation at the UE. The signal may also be referred to by other names. That is, the network node may send timing information indicating when the training signal is sent for the UE. For example, the timing information may indicate the time slot number or at least one symbol number in which the network node will send the training signal for the UE. The UE may estimate the FDRSB correction filter based on the time slot in which the training symbol is sent, and feedback (e.g., send) the calculated or estimated FDRSB correction filter to the network node in response to the training symbol.

[0083] The FDRSB provided over the entire bandwidth may be captured by allocating a single symbol for the training signal. That is, the training signal may be provided within a symbol to capture the FDRSB over the entire bandwidth. More than one symbol of the training signal may be provided to improve processing gain.

[0084] In some aspects, the process of eliminating FDRSB may include utilizing information from a UE or multiple UEs to assist a network node to implement (eg, determine and apply) an FDRSB correction filter.

[0085] The network node may decide the period of requesting FDRSB estimation from the UE. That is, FDRSB estimation may be performed at a specific period, and the network node may configure the period of FDRSB estimation.

[0086] The network node may determine the width of the FDRSB training signal in frequency based on the operating BW of the network node. That is, if the network node operates with a narrower BW, the network node may configure the width of the FDRSB training signal to improve the estimated accuracy of the FDRSB correction. For example, if the operating bandwidth is narrow, the base station or network node may configure a narrower frequency resource width for the FDRSB training signal. A narrower FDRSB training signal may provide a higher received SNR (e.g., on the training signal) because the network node transmit power is distributed over a narrower frequency resource width. Similarly, if the operating bandwidth is wider, the FDRSB training signal may use a wider set of frequency resources.

[0087] In wireless communications in the frequency range below terahertz (THz), network nodes may be configured with a large number of Tx chains to form narrow beams, which may compensate for path losses (e.g., that may be caused by high carrier frequencies). Therefore, correction of FDRSB for these multiple chains may be provided to reduce noise caused by FDRSB.

[0088] The UE may estimate a composite FDRSB (eg, mixed measurements of multiple FDRSB elements from multiple Tx chains) and provide the estimate to the network node, which enables reducing the dimensionality of estimating / correcting the FDRSB at the network node compared to performing estimation and correction for each Tx chain.

[0089] The UE may estimate the composite FDRSB, and the estimation / correction may depend on the precoder or beamformer used for the training signal, and the estimation of the composite FDRSB may be updated or re-initiated in response to a precoder change (eg, whenever the precoder changes).

[0090] Figure 4 An example 400 of composite FDRSB estimation and cancellation for wireless communication between a network node 410 and a UE 450 is illustrated. The network node 410 may be a base station 102 or a component of a base station, such as one or more of a CU 110, a DU 130, or a RU 140. The network node 410 may include a composite FDRSB filter 412, a plurality of IQ modulators (including a first IQ modulator 420 and an Nth IQ modulator 428), and a plurality of antenna panels or antenna assemblies (including a first antenna panel 430 and an Nth antenna panel 438). For example, the plurality of antenna panels may include a plurality of RF panels / RRH units. For example, the first antenna panel 430 may include L antennas, and the Nth antenna panel may include L antennas.

[0091] Before estimating the composite FDRSB filter between the network node 410 and the UE 450, the network node may send a training signal S 402 to the UE 450 via a wireless link.ij The network node Tx side generates multiple RF panels / RRH units that form beams and configures the link. For example, each of the multiple antenna panels including the first antenna panel 430 and the Nth antenna panel 438 of the network node 410 may be configured with coefficients P ij To generate beamforming, thereby establishing a wireless link with UE 450. Multiple RF panels / RRH units may be fed with N individual IQ modulators (e.g., first IQ modulator 420 to Nth IQ modulator 428). Each of the N IQ modulators may be impaired by a different FDRSB. That is, the first IQ modulator 420 may experience a first FDRSB, and the Nth IQ modulator 428 may experience an Nth FDRSB.

[0092] The training signal S can be applied to N IQ modulators, where the i-th IQ modulator can be associated with the i-th FDRSB impairment component. Therefore, the IQ modulated training signal can be expressed as: i [k]=S[k]+F i [k]·S * [-k], where S[k] may refer to the training signal in the FD domain, and F i [k] may refer to the FDRSB impairment component of the i-th modulator, and k may represent the index of the subcarrier. For example, if the IFFT size is 4096, k may take an integer value between 0 and 4095, for example, {0, 1, ..., 4095}.

[0093] IQ modulated training signal∑ i Z i [k] may be transmitted to the UE 450 via a plurality of antenna panels. The signal received at the UE side may include Z after passing through the beamformer and being received on the channel H. i [k], and the received signal can be expressed as Y[k]=∑ i Z i [k]∑ j P ij [k]H ij [k] = ∑ i Z i [k]G i [k]. Here, G i [k] = ∑ j P ij [k]H ij [k] may denote the beamformer and the channel H. Therefore, the received signal may be further expressed as:

[0094] Y[k]=∑ i (S[k]+F i [k]·S *[-k])G i [k]=S[k]∑ i G i [k]+S * [-k]∑ i G i [k]F i [k].

[0095] Here,∑ i G i [k] can be called C main [k] of the main channels, and ∑ i G i [k]F i [k] can be called C FDRSB [k] FDRSB channel.

[0096] UE 450 may include an FDRSB estimator 452, which may include an equalizer for eliminating the primary channel C main [k], which is the equalized signal Y at the UE out [k], can be expressed as:

[0097]

[0098] Here, may represent the composite FDRSB component observed at the UE, and Can be called C FdRSB.post.eq [k]. Therefore, the equalized signal Y at the UE out [k] can be expressed as:

[0099] Y out [k]=S[k]+S * [-k]·C FDRSB.post.eq [k]

[0100] In some aspects, the training signal S[k] can be designed based on the observed equalized signal Y out [k] to simplify UE's understanding of the composite FDRSB component S * [-k]·C FDRSB.post.eq Estimate of [k].

[0101] Figure 5Ais an example of a training signal 500 for estimating a composite FDRSB. The training signal 500 may include a first set of tones 502 and a second set of tones 504. A tone may refer to a single subcarrier in frequency. The indices of the subcarriers may be assigned with reference to a center frequency of a bandwidth of the training signal S[k] (including multiple subcarriers). That is, the first set of tones 502 may be associated with a first set of subcarriers having negative index numbers, and the second set of tones 504 may be associated with a second set of subcarriers having positive index numbers.

[0102] Figure 5A The training signal 500 (e.g., from Figure 4 In an example of S), the training signal includes: a first frequency tone set 502, which is associated with a first subcarrier set with an odd index number for subcarrier frequencies associated with negative index numbers; and a second frequency tone set 504, which is associated with a second subcarrier set with an even index number for subcarrier frequencies associated with positive index numbers. Therefore, the mirror subcarriers of the subcarriers carrying the first frequency tone set 502 and the second frequency tone set 504 (for example, positive numbered subcarriers that mirror negative numbered subcarriers such as 1 and -1) can be null subcarriers. Here, the mirror subcarrier may refer to a mirrored (symmetrical) subcarrier of a reference center frequency, and the null subcarrier may refer to a subcarrier that does not carry a frequency tone. For example, the mirror subcarrier of a positive subcarrier index is the corresponding negative subcarrier index, for example, -1 and 1 are mirrored subcarriers, and 2- and 2 are mirrored subcarriers. In addition, the negative index number may represent a subcarrier frequency that is lower than the center frequency of multiple subcarriers, and the positive index number may represent a subcarrier frequency that is higher than the center frequency of multiple subcarriers.

[0103] Figure 5A The example of training signal 500 illustrated in provides: a first frequency tone set 502, which is associated with a first subcarrier set having odd index numbers for subcarrier frequencies associated with negative index numbers; and a second frequency tone set 504, which is associated with a second subcarrier set having even index numbers for subcarrier frequencies associated with positive index numbers, but the present disclosure is not limited thereto. For example, for subcarrier frequencies associated with positive index numbers, the first frequency tone set may be associated with a first subcarrier set having odd index numbers; and for subcarrier frequencies associated with negative index numbers, the second frequency tone set may be associated with a second subcarrier set having even index numbers.

[0104] Figure 5B is an example of an equalized signal 550 of the training signal 500 measured at the UE. The equalized signal 550 of the training signal 500 measured at the UE can be represented as Y out [k]=S[k]+S *[-k]·C FDRSB.post.eq [k].

[0105] In one aspect, the equalized signal 550 of the training signal may include a first set of tones 552 and a second set of tones 554, the first set of tones and the second set of tones corresponding to the first set of tones 502 and the second set of tones 504 of the training signal 500, respectively. That is, the first set of tones 552 and the second set of tones 554 may correspond to the out [k]=S[k]+S * [-k]·C FDRSB.post.eq [k] is the equalized signal 550 S[k].

[0106] In another aspect, the equalized signal 550 of the training signal further includes a third set of tones 562 and a fourth set of tones 564. The third set of tones 562 may represent FDRSB impairment components caused by the first set of tones 552, the third set of tones being associated with mirrored (or symmetric) subcarriers with reference to a center frequency of the plurality of subcarriers. Additionally, the fourth set of tones 564 may represent FDRSB impairment components caused by the second set of tones 554, the fourth set of tones being associated with mirrored (or symmetric) subcarriers with reference to a center frequency of the plurality of subcarriers.

[0107] For example, the first set of tones 552 associated with the first set of subcarriers corresponding to negative odd index numbers and the second set of tones 554 associated with the second set of subcarriers corresponding to positive even index numbers and the mirror (symmetrical) subcarriers of the reference center frequency may be null subcarriers, and the third set of tones 562 and the fourth set of tones 564 may be measured in the null subcarriers. That is, the FDRSB impairment components reflected on the mirror subcarriers may leak into the null tones and affect the C FDRSB.post.eq The complexity of the estimation of [k] may be less complex. That is, the third set of tones 562 and the fourth set of tones 564 may correspond to Y represented as out [k]=S[k]+S * [-k]·C FDRSB.post.eq [k] equalized signal 550 S * [-k]·C FDRSB.post.eq [k], and the composite FDRSB filter can be estimated by measuring the response on the mirror tone including the third set of tones 562 and the fourth set of tones 564.

[0108] Once UE 450 estimates the response of the composite FDRSB component, UE 450 may send feedback 440 associated with the composite FDRSB. In one example, UE 450 may calculate or identify a correction filter for resolving the composite FDRSB and may indicate the determined correction filter to the network. For example, feedback 440 may include the composite FDRSB component (e.g., S * [-k]·C FDRSB.post.eq [k] or C FDRSB.post.eq [k]). In other examples, the UE may provide measurement information to the network, and the network node may determine the correction filter based on the measurement from the UE. In some examples, feedback 440 may include a response represented as Y out [k]=S[k]+S * [-k]·C FDRSB.post.eq [k] of the equalized signal 550. In some aspects, the UE may transmit a final correction filter, such as C FDRSB.correction [k]=-C FDRSB.post.eq [k]. In some aspects, the UE may transmit the measurement itself, e.g., Y out [k]=S[k]+S * [-k]×C FDRSB.post.eq [k].

[0109] Figure 6 A block diagram 600 of a composite FDRSB correction is illustrated. The block diagram 600 may include a composite FDRSB correction unit 612 in a network node, followed by a total equivalent composite FDRSB impairment 614. A signal S 602 to be sent to a UE may be input to the composite FDRSB correction unit 612, and the composite FDRSB correction unit 612 may be configured to output a signal denoted as S cor [k]=S[k]+S * [-k]·C FDRSB.correction Correction signal S of [k] cor [k]604.

[0110] Correction signal S cor [k] 604 can be performed by multiple IQ modulators (for example, including Figure 4 a plurality of IQ modulations of a first IQ modulator 420 and an Nth IQ modulator 428), a plurality of antenna panels (eg, including Figure 4 The UE may receive the correction signal S transmitted through the multiple IQ modulators, the multiple antenna panels, and the main channel. cor [k] 604, and obtains The equalized signal Y out[k]606.

[0111] Therefore, the equalized signal Y measured at the UE is out [k]606 can be calculated as:

[0112]

[0113] Therefore, in order to eliminate the FDRSB impairment component, the correction filter can be configured as C FDRSB.correction [k]=-C FDRSB.post.eq [k] That is, based on the training signal sent from -[k] (e.g., Figure 4 , Figure 5A and Figure 5B ) estimated c FDRSB.post.eq [k], the network node may configure the composite FDRSB correction unit 612 so that C FDRSB.correction [k]=-C FDRsB.post.eq [k] to eliminate the FDRSB damage component.

[0114] Therefore, by applying the composite FDRSB correction unit 612, C FDRSB.correction [k]=-C FDRSB.post.eq [k] to eliminate the FDRSB damage component and equalize the signal Y out [k] can be Here, the residual gain 1-(C FDRSB.post.eq [k]) 2 can be ignored, and this residual gain can also be captured and eliminated by the equalizer.

[0115] Figure 7 is an example of a training signal S[k] 700 for estimating a composite FDRSB. The training signal S[k] may be configured to have various shapes, so long as each subcarrier carrying a tone has a null mirror subcarrier relative to a center frequency. That is, the training signal S[k] may include at least one tone transmitted on a first subset of subcarriers among a plurality of subcarriers, and the first subset of subcarriers may be mirrored or symmetric with respect to a center frequency of the plurality of subcarriers to a second subset of subcarriers, the second subset of subcarriers being null subcarriers that may not have the tone of the training signal S[k]. In some aspects, the second subset of subcarriers may be mirror subcarriers of the first subset of subcarriers.

[0116] The example of training signal S[k] 700 illustrates that the training signal S[k] has a four (4) bit resolution, which means that the frequency tone of the training signal S[k] is provided once every four (4) subcarriers. The subcarriers having the frequency tone of the training signal S[k] are configured so that the mirror subcarrier relative to the center frequency is a null subcarrier. The example of training signal S[k] 700 shows that only a portion of the subcarriers are allowed to carry the frequency tone of the training signal S[k]. Since a reduced number of subcarriers are configured to carry the frequency tone of the training signal S[k], the Tx signal power of the training signal S[k] can be divided over a smaller number of frequency tones and each signal frequency tone of the training signal S[k] can have a better SNR. Therefore, the estimation accuracy of the FDRSB impairment component can be improved. In addition, the change of FDRSB in frequency is relatively slow, and the training signal used for FDRSB estimation can be configured with less dense filler signal frequency tones.

[0117] The configuration of the training signal S[k] may be flexible to take into account various possible optimization metrics, while the basic standard for each subcarrier of the frequency tone carrying the training signal S[k] may be configured to have a null mirror subcarrier.

[0118] Figure 8 800 is a call flow diagram of a method of wireless communication. The call flow diagram 800 may include a UE 802 and a network node 804. For example, the network node 804 may be a base station 102 or a component of a base station. The network node 804 may send a training signal for the UE 802 on a plurality of subcarriers, the training signal being sent via a plurality of IQ modulators and a plurality of RF antenna panels; and receive feedback associated with FDRSB based on the training signal. The network node 804 may apply an FDRSB correction filter to at least one signal to be sent to the UE 802, and the FDRSB correction filter may be based on feedback received from the UE 802. The training signal may include at least one frequency tone sent on a first subset of subcarriers of the plurality of subcarriers, the first subset of subcarriers being configured to be symmetric with a second subset of subcarriers relative to a center frequency of the plurality of subcarriers, and the second subset of subcarriers being devoid of the at least one frequency tone of the training signal.

[0119] At 806, the network node 804 may send timing information indicating when to send a training signal for the UE 802. The UE 802 may receive the timing information indicating when to receive the training signal from the network node 804. The training signal may be sent and received using the timing indicated by the timing information. Here, the timing information may include an indication of a time slot number or at least one symbol number in which the training signal is sent to the UE 802, and the indication may be sent at least once in response to a pre-decoder update. The UE 802 may estimate the FDRSB correction filter based on the time slot in which the training symbol may be sent, and feedback or send the calculated or estimated FDRSB correction filter to the network node 804 in response to the training symbol.

[0120] At 808, the network node 804 may send a training signal for the UE 802 on multiple subcarriers, the training signal being sent via multiple IQ modulators and multiple RF antenna panels. The UE 802 may receive the training signal from the network node 804 on multiple subcarriers from the multiple IQ modulators and multiple RF antenna panels.

[0121] In one aspect, at least one frequency tone of the training signal may be sent on a first subset of subcarriers among a plurality of subcarriers, the first subset of subcarriers being configured to be symmetric with respect to a center frequency of the plurality of subcarriers and the second subset of subcarriers being devoid of at least one frequency tone of the training signal.

[0122] In one example, the first subcarrier subset may include even-numbered subcarriers on a first side of a center frequency of the plurality of subcarriers and odd-numbered subcarriers on a second side of a center frequency of the plurality of subcarriers. In another aspect, the training signal may be sent with a timing indicated by the timing information sent at 806.

[0123] In some aspects, the network node 804 may send a training signal to the UE 802 over a link configured on the network node 804 Tx side of multiple antenna panels (e.g., multiple RF panels / RRH units) that may use coefficients P ij To generate beamforming. Multiple antenna panels may be fed with multiple IQ modulators, and each of the multiple IQ modulators may be impaired by a different FDRSB.

[0124] The training signal can be applied to multiple IQ modulators, and the IQ modulated training signal can be expressed as: Z i [k]=S[k]+F i [k]·S * [-k], where S[k] may refer to the training signal in the FD domain, and F i [k] may refer to the FDRSB impairment component of the i-th modulator.

[0125] UE 802 may receive Z after passing through the beamformer and the channel i [k], and the signal received at the UE 802 side can be expressed as Y[k]=∑ i Z i [k]∑ j P ij [k]H ij [k] = ∑ i Z i [k]G i [k]. Here, G i [k] = ∑ j P ij [k]H ij [k] can represent the beamformer and channel. Therefore, the received signal can also be expressed as:

[0126] Y[k]=∑ i (S[k]+F i [k]·S * [-k])G i [k]=S[k]∑ i G i [k]+S * [-k]∑ i G i [k]F i [k].

[0127] Here,∑ i G i [k] can be called C main [k] of the main channels, and ∑ i G i [k]F i [k] can be called C FDRSB [k] FDRSB channel.

[0128] UE 802 may equalize the received signal to eliminate the primary channel C main [k], and the equalized signal Y at UE 802 out [k] can be expressed as:

[0129]

[0130] Here, may represent the composite FDRSB component observed at UE 802, and Can be called C FDRSB.post.eq [k]. Therefore, the equalized signal Y at UE 802 out [k] can be expressed as:

[0131] Y out [k]=S[k]+S * [-k]·C FDRSB.post.eq [k]

[0132] In some aspects, the training signal S[k] can be designed for the UE 802 to obtain the observed equalized signal Y out [k] Easily estimate the composite FDRSB component S * [-k]·C FDRSB.post.eq [k].

[0133] At 810, UE 802 may estimate an FDRSB correction filter based on measurements of a training signal on a second subcarrier subset. To remove the FDRSB impairment component, the correction filter may be configured as C FDRSB.correction [k]=-C FDRSB.post.eq [k] That is, based on the training signal (e.g., Figure 4 , Figure 5A and Figure 5B ) Estimated C FDRSB.post.eq [k], the network node 804 may configure a composite FDRSB correction unit (eg, composite FDRSB correction unit 612) such that C FDRSB.correction [k]=-C FDRSB.post.eq [k] to eliminate the composite FDRSB damage component.

[0134] At 812, UE 802 may send feedback associated with FDRSB to network node 804 based on the training signal. Network node 804 may receive feedback associated with FDRSB based on the training signal. In one example, the feedback may include a measurement of the training signal on the second subcarrier subset. For another example, the feedback received from UE 802 may include an estimate of the FDRSB correction filter measured on the second subcarrier subset. The FDRSB correction filter may be estimated at 810.

[0135] At 814, the network node 804 may estimate an FDRSB correction filter based on the feedback received from the UE 802. To remove the FDRSB impairment component, the correction filter may be configured as C FDRSB.correction [k]=-C FDRSB.post.eq [k] That is, based on the training signal (e.g., Figure 4 , Figure 5A and Figure 5B ) Estimated C FDRSB.post.eq [k], the network node 804 may configure a composite FDRSB correction unit (eg, composite FDRSB correction unit 612) such that C FDRSB.correction [k]=-C FDRSB.post.eq [k] to eliminate the composite FDRSB damage component.

[0136] At 816, the network node 804 may apply a FDRSB correction filter to at least one signal to be sent to the UE 802, the FDRSB correction filter being based on the feedback received from the UE 802. Here, C FDRSB.correction [k]=-C FDRSB.post.eq [k] to eliminate the composite FDRSB damage component.

[0137] At 818, the network node 804 may send the at least one signal via the plurality of IQ modulators to the UE 802. An FDRSB correction filter may be applied to the at least one signal prior to the plurality of IQ modulators.

[0138] Fig. 9 Flowchart 900 of a method of wireless communication. The method may be performed by a network node (e.g., base station 102; network node 410 / 804; network entity 1402 / 1560). The network node may send a training signal for a UE on multiple subcarriers, the training signal being sent via multiple IQ modulators and multiple RF antenna panels; and receive feedback associated with FDRSB based on the training signal. The network node may apply an FDRSB correction filter to at least one signal to be sent to the UE, and the FDRSB correction filter may be based on the feedback received from the UE. The training signal may include at least one frequency tone sent on a first subset of subcarriers in the multiple subcarriers, the first subset of subcarriers being configured to be symmetrical with a second subset of subcarriers relative to a center frequency of the multiple subcarriers, and the second subset of subcarriers being devoid of the at least one frequency tone of the training signal.

[0139] At 906, the network node may send timing information indicating when to send a training signal for the UE. The training signal may be sent and received using the timing indicated by the timing information. Here, the timing information may include an indication of a time slot number or at least one symbol number in which the training signal is sent to the UE, and the indication may be sent at least once in response to a pre-decoder update. The UE may estimate the FDRSB correction filter based on the time slot in which the training symbol may be sent, and feedback or send the calculated or estimated FDRSB correction filter to the network node in response to the training symbol. For example, at 806, the network node 804 may send timing information indicating when to send a training signal for the UE 802. In addition, 906 may be performed by the FDRSB estimation component 198.

[0140] At 908, the network node may transmit a training signal for the UE on multiple subcarriers, the training signal being transmitted via multiple IQ modulators and multiple RF antenna panels. For example, at 808, the network node 804 may transmit a training signal for the UE 802 on multiple subcarriers, the training signal being transmitted via multiple IQ modulators and multiple RF antenna panels. Furthermore, 908 may be performed by the FDRSB estimation component 198.

[0141] In one aspect, at least one frequency tone of the training signal may be sent on a first subset of subcarriers among a plurality of subcarriers, the first subset of subcarriers being configured to be symmetric with respect to a center frequency of the plurality of subcarriers and the second subset of subcarriers being devoid of at least one frequency tone of the training signal.

[0142] In one example, the first subcarrier subset may include even-numbered subcarriers on a first side of a center frequency of the plurality of subcarriers and odd-numbered subcarriers on a second side of a center frequency of the plurality of subcarriers. In another aspect, the training signal may be sent with a timing indicated by the timing information sent at 906.

[0143] In some aspects, the network node may send a training signal to the UE on a link configured on the network node Tx side of multiple antenna panels (e.g., multiple RF panels / RRH units) that may use coefficients P ij To generate beamforming. Multiple antenna panels may be fed with multiple IQ modulators, and each of the multiple IQ modulators may be impaired by a different FDRSB.

[0144] The training signal can be applied to multiple IQ modulators, and the IQ modulated training signal can be expressed as: Z i [k]=S[k]+F i [k]·S * [-k], where S[k] may refer to the training signal in the FD domain, and F i [k] may refer to the FDRSB impairment component of the i-th modulator.

[0145] The UE can receive Z after passing through the beamformer and the channel i [k], and the signal received at the UE side can be expressed as Y[k] = ∑ i Z i [k]∑ j P ij [k]H jj [k] = ∑ i Z i [k]G i [k]. Here, G i [k] = ∑ jP ij [k]H ij [k] can represent the beamformer and channel. Therefore, the received signal can also be expressed as: Y[k] = ∑ i (S[k]+F i [k]·S * [-k])G i [k]=S[k]∑ i G i [k]+S * [-k]∑ i G i [k]F i [k].

[0146] Here,∑ i G i [k] can be called C main [k] of the main channels, and ∑ i G i [k]F i [k] can be called C FDRSB [k] FDRSB channel.

[0147] The UE can equalize the received signal to eliminate the main channel C main [k], and the equalized signal Y at the UE out [k] can be expressed as:

[0148]

[0149] Here, may represent the composite FDRSB component observed at the UE, and Can be called C FdRSB.post.eq [k]. Therefore, the equalized signal Y at the UE out [k] can be expressed as:

[0150] Y out [k]=S[k]+S * [-k]·C FDRSB.post.eq [k]

[0151] In some aspects, the training signal S[k] can be designed for the UE to learn the observed equalized signal Y out [k] Easily estimate the composite FDRSB component S * [-k]·C FDRSB.post.eq [k].

[0152] At 912, the network node may receive feedback associated with the FDRSB based on the training signal. In one example, the feedback may include a measurement of the training signal on the second subcarrier subset. As another example, the feedback received from the UE may include an estimate of the FDRSB correction filter measured on the second subcarrier subset. The FDRSB correction filter may be estimated at 910. For example, at 812, the network node 804 may receive feedback associated with the FDRSB based on the training signal. In addition, 912 may be performed by the FDRSB estimation component 198.

[0153] At 914, the network node may estimate the FDRSB correction filter based on the feedback received from the UE. To eliminate the FDRSB impairment component, the correction filter may be configured as C FDRSB.correction [k]=-C FDRSB.post.eq [k] That is, based on the training signal (e.g., Figure 4 , Figure 5A and Figure 5B ) Estimated C FDRSB.post.eq [k], the network node may configure a composite FDRSB correction unit (eg, composite FDRSB correction unit 612) such that C FDRSB.correction [k]=-C FDRSB.post.eq [k] to eliminate the composite FDRSB impairment component. For example, at 814, the network node 804 can estimate the FDRSB correction filter based on the feedback received from the UE 802. In addition, 914 can be performed by the FDRSB estimation component 198.

[0154] At 916, the network node may apply a FDRSB correction filter to at least one signal to be sent to the UE, the FDRSB correction filter being based on the feedback received from the UE. FDRSB.correction [k]=-C FDRSB.post.eq [k] to eliminate the composite FDRSB impairment component. For example, at 816, the network node 804 can apply an FDRSB correction filter to at least one signal to be sent to the UE 802, the FDRSB correction filter being based on feedback received from the UE 802. In addition, 916 can be performed by the FDRSB estimation component 198.

[0155] At 918, the network node may send the at least one signal to the UE 802 via the plurality of IQ modulators. The FDRSB correction filter may be applied to the at least one signal before the plurality of IQ modulators. For example, at 818, the network node 804 may send the at least one signal to the UE 802 via the plurality of IQ modulators. In addition, 918 may be performed by the FDRSB estimation component 198.

[0156] Fig.101000 is a flow chart of a method of wireless communication. The method may be performed by a network node (e.g., base station 102; network node 410 / 804; network entity 1402 / 1560). The network node may send a training signal for a UE on multiple subcarriers, the training signal being sent via multiple IQ modulators and multiple RF antenna panels; and receive feedback associated with FDRSB based on the training signal. The network node may apply an FDRSB correction filter to at least one signal to be sent to the UE, and the FDRSB correction filter may be based on the feedback received from the UE. The training signal may include at least one frequency tone sent on a first subset of subcarriers in the multiple subcarriers, the first subset of subcarriers being configured to be symmetric with a second subset of subcarriers relative to a center frequency of the multiple subcarriers, and the second subset of subcarriers being devoid of the at least one frequency tone of the training signal.

[0157] At 1008, the network node may transmit a training signal for the UE on a plurality of subcarriers, the training signal being transmitted via a plurality of IQ modulators and a plurality of RF antenna panels. For example, at 808, the network node 804 may transmit a training signal for the UE 802 on a plurality of subcarriers, the training signal being transmitted via a plurality of IQ modulators and a plurality of RF antenna panels. Furthermore, 1008 may be performed by the FDRSB estimation component 198.

[0158] In one aspect, at least one frequency tone of the training signal may be sent on a first subset of subcarriers among a plurality of subcarriers, the first subset of subcarriers being configured to be symmetric with respect to a center frequency of the plurality of subcarriers and the second subset of subcarriers being devoid of at least one frequency tone of the training signal.

[0159] In one example, the first subcarrier subset may include even-numbered subcarriers on a first side of a center frequency of the plurality of subcarriers and odd-numbered subcarriers on a second side of a center frequency of the plurality of subcarriers. In another aspect, the training signal may be transmitted with a timing indicated by the transmitted timing information.

[0160] In some aspects, the network node may send a training signal to the UE on a link configured on the network node Tx side of multiple antenna panels (e.g., multiple RF panels / RRH units) that may use coefficients P ij To generate beamforming. Multiple antenna panels may be fed with multiple IQ modulators, and each of the multiple IQ modulators may be impaired by a different FDRSB.

[0161] The training signal can be applied to multiple IQ modulators, and the IQ modulated training signal can be expressed as: Z i [k]=S[k]+Fi [k]·S * [-k], where S[k] may refer to the training signal in the FD domain, and F i [k] may refer to the FDRSB impairment component of the i-th modulator.

[0162] The UE can receive Z after passing through the beamformer and the channel i [k], and the signal received at the UE side can be expressed as Y[k] = ∑ i Z i [k]∑ j P ij [k]H ij [k] = ∑ i Z i [k]G i [k]. Here, G i [k] = ∑ j P ij [k]H ij [k] can represent the beamformer and channel. Therefore, the received signal can also be expressed as: Y[k] = ∑ i (S[k]+F i [k]·S * [-k])G i [k]=S[k]∑ i G i [k]+S * [-k]∑ i G i [k]F i [k].

[0163] Here,∑ i G i [k] can be called C main [k] of the main channels, and ∑ i G i [k]F i [k] can be called C FDRSB [k] FDRSB channel.

[0164] The UE can equalize the received signal to eliminate the main channel C main [k], and the equalized signal Y at the UE out [k] can be expressed as:

[0165]

[0166] Here, may represent the composite FDRSB component observed at the UE, and Can be called C FDRSB.post.eq [k]. Therefore, the equalized signal Y at the UEout [k] can be expressed as:

[0167] Y out [k]=S[k]+S * [-k]·C FDRSB.post.eq [k]

[0168] In some aspects, the training signal S[k] can be designed for the UE to learn the observed equalized signal Y out [k] Easily estimate the composite FDRSB component S * [-k]·C FDRSB.post.eq [k].

[0169] At 1012, the network node may receive feedback associated with FDRSB based on the training signal. In one example, the feedback may include a measurement of the training signal on the second subcarrier subset. As another example, the feedback received from the UE may include an estimate of the FDRSB correction filter measured on the second subcarrier subset. The FDRSB correction filter may be estimated. For example, at 812, the network node 804 may receive feedback associated with FDRSB based on the training signal. In addition, 1012 may be performed by the FDRSB estimation component 198.

[0170] At 1016, the network node may apply a FDRSB correction filter to at least one signal to be sent to the UE, the FDRSB correction filter being based on the feedback received from the UE. FDRSB.correction [k]=-C FDRSB.post.eq [k] to eliminate the composite FDRSB impairment component. For example, at 816, the network node 804 can apply an FDRSB correction filter to at least one signal to be sent to the UE 802, the FDRSB correction filter being based on feedback received from the UE 802. In addition, 1016 can be performed by the FDRSB estimation component 198.

[0171] Fig.11 1100 is a flow chart of a method of wireless communication. The method may be performed by a UE (e.g., UE 104 / 450 / 802; device 1304). The UE may receive a training signal from a network node on a plurality of subcarriers, the training signal being received via a plurality of IQ modulators and a plurality of RF antenna panels; and send feedback associated with an FDRSB based on the training signal. The training signal may include at least one frequency tone sent on a first subset of subcarriers in the plurality of subcarriers, the first subset of subcarriers being configured to be symmetric with a second subset of subcarriers relative to a center frequency of the plurality of subcarriers, and the second subset of subcarriers being devoid of the at least one frequency tone of the training signal.

[0172] At 1106, the UE may receive timing information indicating when a training signal is received from a network node. The training signal may be sent and received using the timing indicated by the timing information. Here, the timing information may include an indication of a time slot number or at least one symbol number in which the training signal is sent to the UE, and the indication may be sent at least once in response to a pre-decoder update. The UE may estimate an FDRSB correction filter based on the time slot in which the training symbol may be sent, and feedback or send the calculated or estimated FDRSB correction filter to the network node in response to the training symbol. For example, at 806, UE802 may receive timing information indicating when a training signal is received from network node 804. In addition, 1106 may be performed by FDRSB correction component 199.

[0173] At 1108, the UE may receive a training signal from the network node on multiple subcarriers from multiple IQ modulators and multiple RF antenna panels. For example, at 808, UE 802 may receive a training signal from network node 804 on multiple subcarriers from multiple IQ modulators and multiple RF antenna panels. Furthermore, 1108 may be performed by FDRSB correction component 199.

[0174] In one aspect, at least one frequency tone of the training signal may be sent on a first subset of subcarriers among a plurality of subcarriers, the first subset of subcarriers being configured to be symmetric with respect to a center frequency of the plurality of subcarriers and the second subset of subcarriers being devoid of at least one frequency tone of the training signal.

[0175] In one example, the first subcarrier subset may include even-numbered subcarriers on a first side of a center frequency of the plurality of subcarriers and odd-numbered subcarriers on a second side of a center frequency of the plurality of subcarriers. In another aspect, the training signal may be sent with a timing indicated by the timing information sent at 1106.

[0176] In some aspects, the network node may send a training signal to the UE on a link configured on the network node Tx side of multiple antenna panels (e.g., multiple RF panels / RRH units) that may use coefficients P ij To generate beamforming. Multiple antenna panels may be fed with multiple IQ modulators, and each of the multiple IQ modulators may be impaired by a different FDRSB.

[0177] The training signal can be applied to multiple IQ modulators, and the IQ modulated training signal can be expressed as: Z i [k]=S[k]+F i [k]·S * [-k], where S[k] may refer to the training signal in the FD domain, and F i[k] may refer to the FDRSB impairment component of the i-th modulator.

[0178] The UE can receive Z after passing through the beamformer and the channel i [k], and the signal received at the UE side can be expressed as Y[k] = ∑ i Z i [k]∑ j P ij [k]H ij [k] = ∑ i Z i [k]G i [k]. Here, G i [k] = ∑ j P ij [k]H ij [k] can represent the beamformer and channel. Therefore, the received signal can also be expressed as: Y[k] = ∑ i (S[k]+F i [k]·S * [-k])G i [k]=S[k]∑ i G i [k]+S * [-k]∑ i G i [k]F i [k].

[0179] Here,∑ i G i [k] can be called C main [k] of the main channels, and ∑ i G i [k]F i [k] can be called C FDRSB [k] FDRSB channel.

[0180] The UE can equalize the received signal to eliminate the main channel C main [k], and the equalized signal Y at the UE out [k] can be expressed as:

[0181]

[0182] Here, may represent the composite FDRSB component observed at the UE, and Can be called C FDRSB.post.eq [k]. Therefore, the equalized signal Y at the UE out [k] can be expressed as:

[0183] Y out [k]=S[k]+S* [-k]·C FDRSB.post.eq [k]

[0184] In some aspects, the training signal S[k] can be designed for the UE to learn the observed equalized signal Y out [k] Easily estimate the composite FDRSB component S * [-k]·C FDRSB.post.eq [k].

[0185] At 1110, the UE may estimate an FDRSB correction filter based on measurements of the training signal on the second subcarrier subset. To eliminate the FDRSB impairment component, the correction filter may be configured as C FDRsB.correction [k]=-C FDRSB.post.eq [k] That is, based on the training signal (e.g., Figure 4 , Figure 5A and Figure 5B ) Estimated C FDRSB.post.eq [k], the network node 804 may configure a composite FDRSB correction unit (eg, composite FDRSB correction unit 612) such that C FDRSB.correction [k]=-C FDRSB.post.eq [k] to eliminate the composite FDRSB impairment component. For example, at 810, UE 802 can estimate the FDRSB correction filter based on the measurement of the training signal on the second subcarrier subset. In addition, 1110 can be performed by FDRSB correction component 199.

[0186] At 1112, the UE may send feedback associated with the FDRSB to the network node based on the training signal. In one example, the feedback may include a measurement of the training signal on the second subcarrier subset. As another example, the feedback received from the UE may include an estimate of the FDRSB correction filter measured on the second subcarrier subset. The FDRSB correction filter may be estimated at 1110. For example, at 812, the UE 802 may send feedback associated with the FDRSB to the network node 804 based on the training signal. In addition, 1112 may be performed by the FDRSB correction component 199.

[0187] Fig.121200 is a flow chart of a method of wireless communication. The method may be performed by a UE (e.g., UE 104 / 450 / 802; device 1304). The UE may receive a training signal from a network node on a plurality of subcarriers, the training signal being received via a plurality of IQ modulators and a plurality of RF antenna panels; and send feedback associated with an FDRSB based on the training signal. The training signal may include at least one frequency tone sent on a first subset of subcarriers in the plurality of subcarriers, the first subset of subcarriers being configured to be symmetric with a second subset of subcarriers relative to a center frequency of the plurality of subcarriers, and the second subset of subcarriers being devoid of the at least one frequency tone of the training signal.

[0188] At 1208, the UE may receive a training signal from the network node on multiple subcarriers from multiple IQ modulators and multiple RF antenna panels. For example, at 808, UE 802 may receive a training signal from network node 804 on multiple subcarriers from multiple IQ modulators and multiple RF antenna panels. Furthermore, 1208 may be performed by FDRSB correction component 199.

[0189] In one aspect, at least one frequency tone of the training signal may be sent on a first subset of subcarriers among a plurality of subcarriers, the first subset of subcarriers being configured to be symmetric with respect to a center frequency of the plurality of subcarriers and the second subset of subcarriers being devoid of at least one frequency tone of the training signal.

[0190] In one example, the first subcarrier subset may include even-numbered subcarriers on a first side of a center frequency of the plurality of subcarriers and odd-numbered subcarriers on a second side of a center frequency of the plurality of subcarriers. In another aspect, the training signal may be transmitted with a timing indicated by the transmitted timing information.

[0191] In some aspects, the network node may send a training signal to the UE on a link configured on the network node Tx side of multiple antenna panels (e.g., multiple RF panels / RRH units) that may use coefficients P ij To generate beamforming. Multiple antenna panels may be fed with multiple IQ modulators, and each of the multiple IQ modulators may be impaired by a different FDRSB.

[0192] The training signal can be applied to multiple IQ modulators, and the IQ modulated training signal can be expressed as: Z i [k]=S[k]+F i [k]·S * [-k], where S[k] may refer to the training signal in the FD domain, and F i [k] may refer to the FDRSB impairment component of the i-th modulator.

[0193] The UE can receive Z after passing through the beamformer and the channel i [k], and the signal received at the UE side can be expressed as Y[k] = ∑ i Z i [k]∑ j P ij [k]H ij [k] = ∑ i Z i [k]G i [k]. Here, G i [k] = ∑ j P ij [k]H ij [k] can represent the beamformer and channel. Therefore, the received signal can also be expressed as: Y[k] = ∑ i (S[k]+F i [k]·S * [-k])G i [k]=S[k]∑ i G i [k]+S * [-k]∑ i G i [k]F i [k].

[0194] Here,∑ i G i [k] can be called C main [k] of the main channels, and ∑ i G i [k]F i [k] can be called C FDRSB [k] FDRSB channel.

[0195] The UE can equalize the received signal to eliminate the main channel C main [k], and the equalized signal Y at the UE out [k] can be expressed as:

[0196]

[0197] Here, may represent the composite FDRSB component observed at the UE, and Can be called C FDRSB.post.eq [k]. Therefore, the equalized signal Y at the UE out [k] can be expressed as:

[0198] Y out [k]=S[k]+S * [-k]·C FDRSB.post.eq [k]

[0199] In some aspects, the training signal S[k] can be designed for the UE to learn the observed equalized signal Y out [k] Easily estimate the composite FDRSB component S * [-k]·C FDRSB.post.eq [k].

[0200] At 1212, the UE may send feedback associated with the FDRSB to the network node based on the training signal. In one example, the feedback may include a measurement of the training signal on the second subcarrier subset. As another example, the feedback received from the UE may include an estimate of the FDRSB correction filter measured on the second subcarrier subset. The FDRSB correction filter may be estimated. For example, at 812, the UE 802 may send feedback associated with the FDRSB to the network node 804 based on the training signal. In addition, 1212 may be performed by the FDRSB correction component 199.

[0201] Fig.131300 is a diagram illustrating an example of a hardware implementation for an apparatus 1304. The apparatus 1304 may be a UE, a component of a UE, or may implement UE functionality. In some aspects, the apparatus 1204 may include a cellular baseband processor 1324 (also referred to as a modem) coupled to one or more transceivers 1322 (e.g., a cellular RF transceiver). The cellular baseband processor 1324 may include on-chip memory 1324'. In some aspects, the apparatus 1304 may also include one or more subscriber identity module (SIM) cards 1320 and an application processor 1306 coupled to a secure digital (SD) card 1308 and a screen 1310. The application processor 1306 may include on-chip memory 1306'. In some aspects, the device 1304 may also include a Bluetooth module 1312, a WLAN module 1314, an SPS module 1316 (e.g., a GNSS module), one or more sensor modules 1318 (e.g., an atmospheric pressure sensor / altimeter; a motion sensor such as an inertial measurement unit (IMU), a gyroscope, and / or an accelerometer; light detection and ranging (LIDAR), radio-aided detection and ranging (RADAR), sound navigation and ranging (SONAR), a magnetometer, audio, and / or other technologies for positioning), an additional memory module 1326, a power source 1330, and / or a camera 1332. The Bluetooth module 1312, the WLAN module 1314, and the SPS module 1316 may include an on-chip transceiver (TRX) (or in some cases, only a receiver (RX)). The Bluetooth module 1312, the WLAN module 1314, and the SPS module 1316 may include their own dedicated antennas and / or communicate using antennas 1380. The cellular baseband processor 1324 communicates with the UE 104 and / or with the RU associated with the network entity 1302 through the transceiver 1322 via one or more antennas 1380. The cellular baseband processor 1324 and the application processor 1306 may each include a computer-readable medium / memory 1324', 1306', respectively. The additional memory module 1326 may also be considered as a computer-readable medium / memory. Each computer-readable medium / memory 1324', 1306', 1326 may be non-transitory. The cellular baseband processor 1324 and the application processor 1306 are each responsible for general processing, including executing software stored on a computer-readable medium / memory. The software, when executed by the cellular baseband processor 1324 / application processor 1306, enables the cellular baseband processor 1324 / application processor 1306 to perform the various functions described above. The computer-readable medium / memory may also be used to store data manipulated by the cellular baseband processor 1324 / application processor 1306 when executing the software.The cellular baseband processor 1324 / application processor 1306 may be a component of the UE 350 and may include the memory 360 and / or at least one of the TX processor 368, the RX processor 356, and the controller / processor 359. In one configuration, the device 1304 may be a processor chip (modem and / or application) and include only the cellular baseband processor 1324 and / or the application processor 1306, and in another configuration, the device 1304 may be the entire UE (e.g., see. Figure 3 350) and includes additional modules of device 1304.

[0202] As discussed above, the FDRSB estimation component 198 is configured to: receive a training signal from a network node on a plurality of subcarriers from a plurality of IQ modulators and a plurality of RF antenna panels; and send feedback associated with the FDRSB to the network node based on the training signal, wherein at least one frequency tone of the training signal is received on a first subset of subcarriers in the plurality of subcarriers, the first subset of subcarriers being configured to be symmetrical with respect to a center frequency of the plurality of subcarriers and the second subset of subcarriers being devoid of the at least one frequency tone of the training signal. The FDRSB estimation component 198 may also be configured to perform a combination of Fig.11 , Fig.12 The various aspects described in the method and / or by the UE in Figure 81304. The FDRSB estimation component 198 may be within the cellular baseband processor 1324, the application processor 1306, or both the cellular baseband processor 1324 and the application processor 1306. The FDRSB estimation component 198 may be one or more hardware components specifically configured to perform the stated processes / algorithms, implemented by one or more processors configured to perform the stated processes / algorithms, stored in a computer readable medium for implementation by one or more processors, or some combination of the foregoing. As shown, the device 1304 may include a variety of components configured for various functions. In one configuration, the apparatus 1304 (and specifically, the cellular baseband processor 1324 and / or the application processor 1306) includes: a component for sending a training signal for a UE on a plurality of subcarriers, the training signal being sent via a plurality of IQ modulators and a plurality of RF antenna panels; a component for receiving feedback associated with FDRSB based on the training signal; and a component for applying an FDRSB correction filter to at least one signal to be sent to the UE, the FDRSB correction filter being based on the feedback received from the UE. In one configuration, at least one frequency tone of the training signal is sent on a first subset of subcarriers among the plurality of subcarriers, the first subset of subcarriers being configured to be symmetrical to a second subset of subcarriers relative to a center frequency of the plurality of subcarriers, and the second subset of subcarriers being devoid of at least one frequency tone of the training signal. In one configuration, the first subset of subcarriers includes even-numbered subcarriers on a first side of a center frequency of the plurality of subcarriers and odd-numbered subcarriers on a second side of a center frequency of the plurality of subcarriers. In one configuration, the feedback includes a measurement of the training signal on the second subset of subcarriers. In one configuration, the feedback received from the UE includes an estimate of the FDRSB correction filter measured on the second subset of subcarriers. In one configuration, the device 1304 (and specifically, the cellular baseband processor 1324 and / or the application processor 1306) also includes a component for estimating the FDRSB correction filter based on the feedback received from the UE. In one configuration, the device 1304 (and specifically, the cellular baseband processor 1324 and / or the application processor 1306) also includes a component for sending timing information indicating when a training signal is sent to the UE, wherein the training signal is sent using the timing indicated by the timing information. In one configuration, the indication is sent at least once in response to a predecoder update. In one configuration, the device 1304 (and specifically, the cellular baseband processor 1324 and / or the application processor 1306) also includes a component for sending at least one signal to the UE via multiple IQ modulators, wherein the FDRSB correction filter is applied to the at least one signal prior to the multiple IQ modulators. The device may also include a component for performing a combination Fig.11 , Fig.12The various aspects described in the method and / or by the UE in Figure 8 1304. The component may be the FDRSB estimation component 198 of the device 1304 configured to perform the functions recited by the component. As described above, the device 1304 may include the TX processor 368, the RX processor 356, and the controller / processor 359. Therefore, in one configuration, the component may be the TX processor 368, the RX processor 356, and / or the controller / processor 359 configured to perform the functions recited by the component.

[0203] Fig.141400 is a diagram illustrating an example of a hardware implementation for a network entity 1402. The network entity 1402 may be a BS, a component of a BS, or may implement BS functionality. The network entity 1402 may include at least one of a CU 1410, a DU 1430, or a RU 1440. For example, depending on the layer functionality handled by the FDRSB correction component 199, the network entity 1402 may include a CU 1410; both a CU 1410 and a DU 1430; each of the CU 1410, the DU 1430, and the RU 1440; the DU 1430; both a DU 1430 and a RU 1440; or a RU 1440. The CU 1410 may include a CU processor 1412. The CU processor 1412 may include an on-chip memory 1412'. In some aspects, the CU 1410 may also include an additional memory module 1414 and a communication interface 1418. CU1410 communicates with DU 1430 via a midhaul link (such as an F1 interface). DU 1430 may include a DU processor 1432. DU processor 1432 may include on-chip memory 1432'. In some aspects, DU 1430 may also include an additional memory module 1434 and a communication interface 1438. DU 1430 communicates with RU 1440 via a fronthaul link. RU 1440 may include a RU processor 1442. RU processor 1442 may include on-chip memory 1442'. In some aspects, RU 1440 may also include an additional memory module 1444, one or more transceivers 1446, an antenna 1480, and a communication interface 1448. RU 1440 communicates with UE 104. On-chip memory 1412', 1432', 1442' and additional memory modules 1414, 1434, 1444 may each be considered a computer-readable medium / memory. Each computer readable medium / memory may be non-transitory. Each of processors 1412, 1432, 1442 is responsible for general processing, including executing software stored on the computer readable medium / memory. The software, when executed by the corresponding processor, causes the processor to perform the various functions described above. The computer readable medium / memory may also be used to store data manipulated by the processor when executing the software.

[0204] As discussed above, the FDRSB correction component 199 is configured to: send a training signal for a UE on a plurality of subcarriers, the training signal being sent via a plurality of IQ modulators and a plurality of RF antenna panels; receive feedback associated with FDRSB based on the training signal; and apply an FDRSB correction filter to at least one signal to be sent to the UE, the FDRSB correction filter being based on the feedback received from the UE. The FDRSB correction component 199 may be configured to perform a combination of Fig. 9 , Fig.10The aspects described in the method and / or by the network node in Figure 8 The FDRSB correction component 199 may be within one or more processors of one or more of the CU 1410, DU 1430, and RU 1440. The FDRSB correction component 199 may be one or more hardware components specifically configured to perform the stated process / algorithms, implemented by one or more processors configured to perform the stated process / algorithms, stored in a computer-readable medium for implementation by one or more processors, or some combination of the above. The network entity 1402 may include a variety of components configured for various functions. In one configuration, the network entity 1402 includes: a component for receiving a training signal from a network node on multiple subcarriers from multiple IQ modulators and multiple RF antenna panels; and a component for sending feedback associated with FDRSB to the network node based on the training signal, wherein at least one frequency tone of the training signal is received on a first subcarrier subset of the multiple subcarriers, the first subcarrier subset is configured to be symmetric with a second subcarrier subset relative to a center frequency of the multiple subcarriers, and the second subcarrier subset is absent from the at least one frequency tone of the training signal. In one configuration, the first subcarrier subset includes even-numbered subcarriers on a first side of the center frequency of the multiple subcarriers and odd-numbered subcarriers on a second side of the center frequency of the multiple subcarriers. In one configuration, a component for estimating an FDRSB correction filter based on a measurement of the training signal on the second subcarrier subset, wherein the feedback includes the FDRSB correction filter. In one configuration, the feedback includes a measurement of the training signal on the second subcarrier subset. In one configuration, the network entity 1402 further comprises means for receiving timing information indicating when a training signal is received from a network node, wherein the training signal is received using the timing indicated by the timing information. In one configuration, the indication is received at least once in response to a pre-decoder update. The network entity may comprise means for performing a combined Fig. 9 , Fig.10 The aspects described in the method and / or by the network node in Figure 8 1402. The component may be a FDRSB correction component 199 of the network entity 1402 configured to perform the functions recited by the component. As described above, the network entity 1402 may include a TX processor 316, an RX processor 370, and a controller / processor 375. Therefore, in one configuration, the component may be a TX processor 316, an RX processor 370, and / or a controller / processor 375 configured to perform the functions recited by the component.

[0205] It should be understood that the specific order or hierarchy of the blocks in the disclosed process / flowchart is merely an illustration of the exemplary method. It should be understood that the specific order or hierarchy of the blocks in the process / flowchart may be rearranged based on design preferences. Further, some blocks may be combined or omitted. The attached method claims provide the elements of the various blocks in a sample order, but are not limited to the specific order or hierarchy provided.

[0206] The foregoing description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects. Therefore, the claims are not limited to the various aspects described herein, but should be given the full scope consistent with the language claims. Unless otherwise specified, reference to an element in the singular form does not mean "one and only one", but "one or more". Terms such as "if", "when" and "while" do not mean a direct temporal relationship or reaction. That is, these phrases, such as "when ...", do not mean an immediate action in response to the occurrence of an action or during the occurrence of an action, but simply imply that if the conditions are met, the action will occur, but no specific or immediate time limit is required for the occurrence of the action. The word "exemplary" is used herein to mean "used as an example, instance or illustration". Any aspect described as "exemplary" herein is not necessarily interpreted as being preferred or having advantages over other aspects. Unless otherwise specified, 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, which may include multiple A, multiple B, or multiple C. Specifically, combinations such as "at least one of A, B, or C", "one or more of A, B, or C", "at least one of A, B, and C", "one or more of A, B, and C", and "A, B, C, or any combination thereof" may be only A, only B, only C, A and B, A and C, B and C, or A and B and C, where any such combination may contain one or more members of A, B, or C. A set should be interpreted as a set of elements, where the number of elements is one or more. Thus, for a set of X, X will include one or more elements. If the first device receives data from the second device or sends data to the second device, data may be directly received / sent between the first device and the second device, or indirectly received / sent between the first device and the second device through a collection of devices. All structural and functional equivalents of the elements of the various aspects described throughout the present disclosure that are known or will later be known to a person of ordinary skill in the art are expressly incorporated herein by reference and are covered by the claims. In addition, nothing disclosed herein is intended to be dedicated to the public, regardless of whether such disclosure is explicitly stated in the claims. Words such as "module", "mechanism", "element", "device" cannot replace the word "component". Therefore, no claim element will be understood as a component plus function unless the element is explicitly stated using the phrase "component for..."

[0207] As used herein, the phrase "based on" should not be interpreted as referring to a closed set of information, one or more conditions, one or more factors, etc. In other words, the phrase "based on A" (where "A" can be information, a condition, a factor, etc.) should be interpreted as "based at least on A" unless specifically stated differently.

[0208] The following aspects are merely illustrative and may be combined with other aspects or teachings described herein without limitation.

[0209] Aspect 1 is a method for wireless communication at a network node, the method comprising: sending a training signal for a UE on multiple subcarriers, the training signal being sent via multiple IQ modulators and multiple RF antenna panels; receiving feedback associated with FDRSB based on the training signal; and applying an FDRSB correction filter to at least one signal to be sent to the UE, the FDRSB correction filter being based on the feedback received from the UE.

[0210] Aspect 2 is a method according to Aspect 1, wherein at least one frequency tone of the training signal is sent on a first subcarrier subset among the multiple subcarriers, the first subcarrier subset is configured to be symmetrical with a second subcarrier subset relative to the center frequency of the multiple subcarriers, and the second subcarrier subset does not have the at least one frequency tone of the training signal.

[0211] Aspect 3 is a method according to aspect 2, wherein the first subcarrier subset includes even-numbered subcarriers on a first side of the center frequency of the multiple subcarriers and odd-numbered subcarriers on a second side of the center frequency of the multiple subcarriers.

[0212] Aspect 4 is a method according to any one of aspects 2 and 3, wherein the feedback comprises measurement of the training signal on the second subcarrier subset.

[0213] Aspect 5 is a method according to aspect 4, wherein the feedback received from the UE includes an estimate of the FDRSB correction filter measured on the second subcarrier subset.

[0214] Aspect 6 is a method according to any one of aspects 4 and 5, the method further comprising: estimating the FDRSB correction filter based on the feedback received from the UE.

[0215] Aspect 7 is a method according to any one of aspects 1 to 6, the method further comprising: sending timing information indicating when to send the training signal to the UE, wherein the training signal is sent using the timing indicated by the timing information.

[0216] Aspect 8 is the method according to aspect 7, wherein the indication is sent at least once in response to a pre-decoder update.

[0217] Aspect 9 is a method according to any one of Aspects 1 to 8, the method further comprising: sending the at least one signal to the UE via the multiple IQ modulators, wherein the FDRSB correction filter is applied to the at least one signal before the multiple IQ modulators.

[0218] Aspect 10 is an apparatus for wireless communication, the apparatus comprising at least one processor coupled to a memory and configured to implement any one of aspects 1 to 9, the apparatus further comprising a transceiver coupled to the at least one processor.

[0219] Aspect 11 is an apparatus for wireless communication, the apparatus comprising means for implementing any one of aspects 1 to 9.

[0220] Aspect 12 is a non-transitory computer-readable medium storing computer-executable code, wherein the code, when executed by a processor, causes the processor to implement any one of aspects 1 to 9.

[0221] Aspect 13 is a method for performing wireless communication at a UE, the method comprising: receiving a training signal from a network node on multiple subcarriers from multiple IQ modulators and multiple RF antenna panels; and sending feedback associated with FDRSB to the network node based on the training signal, wherein at least one frequency tone of the training signal is received on a first subcarrier subset of the multiple subcarriers, the first subcarrier subset is configured to be symmetrical with a second subcarrier subset relative to a center frequency of the multiple subcarriers, and the second subcarrier subset does not have the at least one frequency tone of the training signal.

[0222] Aspect 14 is a method according to aspect 13, wherein the first subcarrier subset includes even-numbered subcarriers on a first side of the center frequency of the plurality of subcarriers and odd-numbered subcarriers on a second side of the center frequency of the plurality of subcarriers.

[0223] Aspect 15 is a method according to any one of Aspects 13 and 14, the method further comprising: estimating an FDRSB correction filter based on measurements of the training signal on the second subcarrier subset, wherein the feedback includes the FDRSB correction filter.

[0224] Aspect 16 is a method according to any one of aspects 13 to 15, wherein the feedback comprises a measurement of the training signal on the second subcarrier subset.

[0225] Aspect 17 is a method according to any one of aspects 13 to 16, the method further comprising: receiving timing information indicating when the training signal is received from the network node, wherein the training signal is received using the timing indicated by the timing information.

[0226] Aspect 18 is the method according to aspect 17, wherein the indication is received at least once in response to a pre-decoder update.

[0227] Aspect 19 is an apparatus for wireless communication, the apparatus comprising at least one processor coupled to a memory and configured to implement any one of aspects 13 to 18, the apparatus further comprising a transceiver coupled to the at least one processor.

[0228] Aspect 20 is an apparatus for wireless communication, the apparatus comprising means for implementing any one of aspects 13 to 18.

[0229] Aspect 21 is a non-transitory computer readable medium storing computer executable code, wherein the code, when executed by a processor, causes the processor to implement any one of aspects 13 to 18.

Claims

1. An apparatus for wireless communication at a network node, the apparatus comprising: Memory; and at least one processor coupled to the memory and based at least in part on the information stored in the memory, the at least one processor configured to: transmitting a training signal for a user equipment (UE) on a plurality of subcarriers, the training signal being transmitted via a plurality of in-phase (I) and quadrature (Q) (IQ) modulators and a plurality of radio frequency (RF) antenna panels; receiving feedback associated with a frequency dependent vestigial sideband (FDRSB) based on the training signal; as well as An FDRSB correction filter is applied to at least one signal to be sent to the UE, the FDRSB correction filter being based on the feedback received from the UE.

2. The apparatus of claim 1 , further comprising a transceiver coupled to the at least one processor, Wherein the at least one processor is configured to send at least one frequency tone of the training signal on a first subset of subcarriers among the plurality of subcarriers, the first subset of subcarriers being configured to be symmetrical with a second subset of subcarriers relative to a center frequency of the plurality of subcarriers, and the second subset of subcarriers being devoid of the at least one frequency tone of the training signal.

3. The apparatus of claim 2, wherein the first subset of subcarriers comprises even-numbered subcarriers on a first side of the center frequency of the plurality of subcarriers and odd-numbered subcarriers on a second side of the center frequency of the plurality of subcarriers.

4. The apparatus of claim 2, wherein the feedback comprises measurements of the training signal on the second subset of subcarriers.

5. The apparatus of claim 4, wherein the feedback from the UE comprises an estimate of the FDRSB correction filter measured on the second subset of subcarriers.

6. The apparatus of claim 4, wherein the at least one processor is further configured to: The FDRSB correction filter is estimated based on the feedback received from the UE.

7. The apparatus of claim 1 , wherein the at least one processor is further configured to: sending timing information indicating when to send the training signal to the UE, The at least one processor is configured to transmit the training signal using the timing indicated by the timing information.

8. The apparatus of claim 7, wherein the at least one processor is configured to send the timing information at least once in response to a pre-decoder update.

9. The apparatus of claim 1 , wherein the at least one processor is further configured to: transmitting the at least one signal to the UE via the plurality of IQ modulators, Wherein the FDRSB correction filter is applied to the at least one signal prior to the plurality of IQ modulators.

10. An apparatus for wireless communication at a user equipment (UE), the apparatus comprising: Memory; and at least one processor coupled to the memory and based at least in part on the information stored in the memory, the at least one processor configured to: receiving a training signal from a network node on a plurality of subcarriers from a plurality of in-phase (I) and quadrature (Q) (IQ) modulators and a plurality of radio frequency (RF) antenna panels; as well as sending feedback associated with a frequency dependent vestigial sideband (FDRSB) to the network node based on the training signal, Wherein the at least one processor is configured to receive at least one frequency tone of the training signal on a first subset of subcarriers among the plurality of subcarriers, the first subset of subcarriers being configured to be symmetrical with respect to a center frequency of the plurality of subcarriers and the second subset of subcarriers being devoid of the at least one frequency tone of the training signal.

11. The apparatus of claim 10, further comprising a transceiver coupled to the at least one processor, Wherein the first subcarrier subset includes even-numbered subcarriers on a first side of the center frequency of the plurality of subcarriers and odd-numbered subcarriers on a second side of the center frequency of the plurality of subcarriers.

12. The apparatus of claim 10, wherein the at least one processor is further configured to: estimating an FDRSB correction filter based on measurements of the training signal on the second subset of subcarriers, Wherein the feedback includes the FDRSB correction filter.

13. The apparatus of claim 10, wherein the feedback comprises a measurement of the training signal on the second subset of subcarriers.

14. The apparatus of claim 10, wherein the at least one processor is further configured to: receiving timing information indicating when the training signal is received from the network node, The reception of the training signal is based on the timing indicated by the timing information.

15. The apparatus of claim 14, wherein the at least one processor is configured to receive the timing information at least once in response to a pre-decoder update.

16. A method for wireless communication at a network node, the method comprising: transmitting a training signal for a user equipment (UE) on a plurality of subcarriers, the training signal being transmitted via a plurality of in-phase (I) and quadrature (Q) (IQ) modulators and a plurality of radio frequency (RF) antenna panels; receiving feedback associated with a frequency dependent vestigial sideband (FDRSB) based on the training signal; as well as An FDRSB correction filter is applied to at least one signal to be sent to the UE, the FDRSB correction filter being based on the feedback received from the UE.

17. A method according to claim 16, wherein at least one frequency tone of the training signal is sent on a first subcarrier subset among the multiple subcarriers, the first subcarrier subset is configured to be symmetrical with a second subcarrier subset relative to the center frequency of the multiple subcarriers, and the second subcarrier subset does not have the at least one frequency tone of the training signal.

18. The method of claim 17, wherein the first subset of subcarriers comprises even-numbered subcarriers on a first side of the center frequency of the plurality of subcarriers and odd-numbered subcarriers on a second side of the center frequency of the plurality of subcarriers.

19. The method of claim 17, wherein the feedback comprises measurements of the training signal on the second subset of subcarriers.

20. The method of claim 19, wherein the feedback received from the UE comprises an estimate of the FDRSB correction filter measured on the second subset of subcarriers.

21. The method according to claim 19, further comprising: The FDRSB correction filter is estimated based on the feedback received from the UE.

22. The method according to claim 16, further comprising: sending timing information indicating when to send the training signal to the UE, The training signal is transmitted using the timing indicated by the timing information.

23. The method of claim 22, wherein the timing information is sent at least once in response to a pre-decoder update.

24. The method according to claim 16, further comprising: transmitting the at least one signal to the UE via the plurality of IQ modulators, Wherein the FDRSB correction filter is applied to the at least one signal prior to the plurality of IQ modulators.

25. A method for wireless communication at a user equipment (UE), the method comprising: receiving a training signal from a network node on a plurality of subcarriers from a plurality of in-phase (I) and quadrature (Q) (IQ) modulators and a plurality of radio frequency (RF) antenna panels; as well as sending feedback associated with a frequency dependent vestigial sideband (FDRSB) to the network node based on the training signal, Wherein the at least one frequency tone of the training signal is received on a first subcarrier subset of the plurality of subcarriers, the first subcarrier subset is configured to be symmetrical with a second subcarrier subset relative to a center frequency of the plurality of subcarriers, and the second subcarrier subset is devoid of the at least one frequency tone of the training signal.

26. The method of claim 25, wherein the first subset of subcarriers comprises even-numbered subcarriers on a first side of the center frequency of the plurality of subcarriers and odd-numbered subcarriers on a second side of the center frequency of the plurality of subcarriers.

27. The method according to claim 25, further comprising: estimating an FDRSB correction filter based on measurements of the training signal on the second subset of subcarriers, Wherein the feedback comprises the FDRSB correction filter.

28. The method of claim 25, wherein the feedback comprises measurements of the training signal on the second subset of subcarriers.

29. The method according to claim 25, further comprising: receiving timing information indicating when the training signal is received from the network node, The training signal is received with the timing indicated by the timing information.

30. The method of claim 29, wherein the timing information is received at least once in response to a pre-decoder update.

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