Frequency domain imbalance correction

Abstract

Methods, systems, and devices for wireless communication are described. A user equipment (UE) may refer to a signal from a network entity. The UE may transmit an estimate of a frequency domain imbalance between an in-phase portion of the reference signal and a quadrature-phase portion of the reference signal to the network entity based on a precoding matrix associated with the transmission from the network entity and an estimate of one or more channel conditions between the UE and the network entity. The network entity may perform an imbalance compensation operation that balances the in-phase portion and the quadrature-phase portion of the transmit chain based on the estimate of the frequency domain imbalance. The UE may receive a data transmission from the network entity based on transmitting an indication of the estimation of the frequency domain imbalance.

Description

Cross-references

[0001] This patent application claims priority to U.S. patent application No. 18 / 049,282, entitled “FREQUENCYDOMAIN IMBALANCE CORRECTION,” filed by Regev et al. on October 24, 2022, which is assigned to the assignee of this application and is expressly incorporated herein by reference. Technical Field

[0002] The following relates to wireless communications, including frequency domain imbalance correction. Background Art

[0003] Wireless communication systems are widely deployed to provide various types of communication content, such as voice, video, packet data, messaging, broadcast, etc. These systems may be able to support communication with multiple users by sharing available system resources (e.g., time, frequency, and power). Examples of such multiple access systems include fourth generation (4G) systems (such as long term evolution (LTE) systems, advanced LTE (LTE-A) systems, or LTE-A Pro systems) and fifth generation (5G) systems (which may be referred to as new radio (NR) systems). These systems may employ techniques such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), or discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-S-OFDM). A wireless multiple access communication system may include one or more base stations, each of which supports wireless communications for communication devices, which may be referred to as user equipment (UE).

[0004] In some wireless communication systems, wireless devices may operate in a massive multiple-input multiple-output (MIMO) scenario. To operate in such a scenario, a network entity may use many antennas and many modulators to send multiple downlink signals to many receiving devices. In some cases, a modulator may be used to send both an in-phase portion of a signal and a quadrature-phase portion of a signal. However, these modulators are susceptible to inherent impairments or imbalances (e.g., which may be referred to as frequency domain imbalance), which, in examples where such inherent impairments or imbalances are not eliminated or accounted for, may limit the link performance of one or both of the wireless device or the network entity, as well as other problems. Summary of the invention

[0005] The systems, methods and devices of the disclosure each have several innovative aspects, no single one of which is solely responsible for the desirable attributes disclosed herein.

[0006] One innovative aspect of the subject matter described in the present disclosure can be implemented in a method for wireless communication. The method can include receiving a reference signal from a network entity; sending an indication of an estimate of frequency domain imbalance between an in-phase portion of the reference signal and a quadrature-phase portion of the reference signal to the network entity based on a precoding matrix associated with the transmission from the network entity and an estimate of one or more channel conditions between the UE and the network entity; and receiving a data transmission from the network entity based on sending the indication of the estimate of the frequency domain imbalance.

[0007] Another innovative aspect of the subject matter described in the present disclosure can be implemented in an apparatus for wireless communication. The apparatus may include a processor, a memory coupled to the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to receive a reference signal from a network entity; send an indication of an estimate of a frequency domain imbalance between an in-phase portion of the reference signal and an orthogonal phase portion of the reference signal to the network entity based on a precoding matrix associated with the transmission from the network entity and an estimate of one or more channel conditions between the UE and the network entity; and receive data transmission from the network entity based on sending the indication of the estimate of the frequency domain imbalance.

[0008] Another innovative aspect of the subject matter described in the present disclosure can be implemented in an apparatus for wireless communication. The apparatus may include a component for receiving a reference signal from a network entity; a component for sending an indication of an estimate of frequency domain imbalance between an in-phase portion of the reference signal and a quadrature-phase portion of the reference signal to the network entity based on a precoding matrix associated with the transmission from the network entity and an estimate of one or more channel conditions between the UE and the network entity; and a component for receiving a data transmission from the network entity based on sending the indication of the estimate of frequency domain imbalance.

[0009] Another innovative aspect of the subject matter described in the present disclosure can be implemented in a non-transitory computer-readable medium storing code for wireless communication. The code may include instructions executable by a processor to perform the following operations: receiving a reference signal from a network entity; sending an indication of an estimate of frequency domain imbalance between an in-phase portion of the reference signal and a quadrature-phase portion of the reference signal to the network entity based on a precoding matrix associated with the transmission from the network entity and an estimate of one or more channel conditions between the UE and the network entity; and receiving data transmission from the network entity based on sending the indication of the estimate of frequency domain imbalance.

[0010] Another innovative aspect of the subject matter described in the present disclosure can be implemented in a method for wireless communication. The method may include sending a reference signal to a UE; receiving an indication of a first estimate of a frequency domain imbalance between an in-phase portion of a transmission chain of a network entity and a quadrature-phase portion of a transmission chain of the network entity, the first estimate being based on the reference signal, a precoding matrix associated with a transmission from the network entity, and an estimate of a channel between the UE and the network entity; performing an imbalance compensation operation of balancing the in-phase portion and the quadrature-phase portion of the transmission chain associated with the transmission chain of the network entity based on the first estimate of the frequency domain imbalance; and sending a data transmission to the UE based on performing the imbalance compensation operation.

[0011] Another innovative aspect of the subject matter described in the present disclosure can be implemented in an apparatus for wireless communication. The apparatus may include a processor, a memory coupled to the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to send a reference signal to a UE; receive an indication of a first estimate of a frequency domain imbalance between an in-phase portion of a transmission chain of a network entity and a quadrature-phase portion of a transmission chain of the network entity, the first estimate being based on the reference signal, a precoding matrix associated with a transmission from the network entity, and an estimate of a channel between the UE and the network entity; perform an imbalance compensation operation of an in-phase portion and a quadrature-phase portion of a balanced transmission chain associated with the transmission chain of the network entity based on the first estimate of the frequency domain imbalance; and send data to the UE based on performing the imbalance compensation operation.

[0012] Another innovative aspect of the subject matter described in the present disclosure can be implemented in an apparatus for wireless communication. The apparatus may include means for sending a reference signal to a UE; means for receiving an indication of a first estimate of a frequency domain imbalance between an in-phase portion of a transmission chain of a network entity and a quadrature-phase portion of a transmission chain of the network entity, the first estimate being based on the reference signal, a precoding matrix associated with a transmission from the network entity, and an estimate of a channel between the UE and the network entity; means for performing an imbalance compensation operation of balancing the in-phase portion and the quadrature-phase portion of the transmission chain associated with the transmission chain of the network entity based on the first estimate of the frequency domain imbalance; and means for sending data transmission to the UE based on performing the imbalance compensation operation.

[0013] Another innovative aspect of the subject matter described in the present disclosure can be implemented in a non-transitory computer-readable medium storing code for wireless communication. The code may include instructions executable by a processor to perform the following operations: send a reference signal to a UE; receive an indication of a first estimate of a frequency domain imbalance between an in-phase portion of a transmission chain of a network entity and a quadrature-phase portion of a transmission chain of the network entity, the first estimate being based on the reference signal, a precoding matrix associated with a transmission from the network entity, and an estimate of a channel between the UE and the network entity; perform an imbalance compensation operation of balancing the in-phase portion and the quadrature-phase portion of the transmission chain associated with the transmission chain of the network entity based on the first estimate of the frequency domain imbalance; and send data transmission to the UE based on performing the imbalance compensation operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 An example of a wireless communication system supporting frequency domain imbalance correction according to one or more examples as disclosed herein is illustrated.

[0015] Figure 2 An example of a wireless communication system supporting frequency domain imbalance correction according to one or more examples as disclosed herein is illustrated.

[0016] Figure 3 An example of a wireless communication system supporting frequency domain imbalance correction according to one or more examples as disclosed herein is illustrated.

[0017] Figure 4 An example of a process flow supporting frequency domain imbalance correction according to one or more examples as disclosed herein is illustrated.

[0018] Figure 5 An example of a process flow supporting frequency domain imbalance correction according to one or more examples as disclosed herein is illustrated.

[0019] Figure 6 and Figure 7 A block diagram of a device supporting frequency domain imbalance correction according to one or more examples as disclosed herein is illustrated.

[0020] Figure 8 A block diagram of a communication manager supporting frequency domain imbalance correction according to one or more examples as disclosed herein is illustrated.

[0021] Fig. 9 A diagram of a system including a device supporting frequency domain imbalance correction according to one or more examples as disclosed herein is illustrated.

[0022] Fig.10 and Fig.11A block diagram of a device supporting frequency domain imbalance correction according to one or more examples as disclosed herein is illustrated.

[0023] Fig.12 A block diagram of a communication manager supporting frequency domain imbalance correction according to one or more examples as disclosed herein is illustrated.

[0024] Fig.13 A diagram of a system including a device supporting frequency domain imbalance correction according to one or more examples as disclosed herein is illustrated.

[0025] Figures 14 to 16 A flow chart showing a method of supporting frequency domain imbalance correction according to one or more examples as disclosed herein is illustrated. DETAILED DESCRIPTION

[0026] A network entity may employ a transmit modulator that may modulate an in-phase (I) signal and a quadrature (Q) phase signal (and the modulator may be referred to as an IQ modulator). An IQ modulator may be subject to inherent impairments or imbalances (which may be referred to as frequency domain imbalance, IQ mismatch, or IQ imbalance), which, among other issues, may limit link performance if this condition is not eliminated or not accounted for. For example, such frequency domain imbalance may include mismatched gains between the I portion and the Q portion of the IQ modulator. Therefore, in some other different approaches, the network entity may estimate such imbalance and perform compensatory actions to correct or eliminate the imbalance. However, some wireless communication systems may employ many antennas (e.g., in a massive multiple-input multiple-output (MIMO) scenario) and may employ many IQ modulators, resulting in processing burden, increased complexity, and additional hardware that the network entity may dispose of to estimate and correct the frequency domain imbalance on various transmit chains used in the massive MIMO scenario.

[0027] Various aspects generally relate to correcting frequency domain imbalance, and more specifically to techniques in which one or more user equipment (UE) performs an estimation of frequency domain imbalance (or mismatch) and sends such estimation or information based on the estimation to a network entity for frequency domain imbalance correction at the network entity. For example, the network entity may send a signal such as a training or reference signal to one or more UEs, and the one or more UEs may estimate the frequency domain imbalance using the signal received through each of a plurality of corresponding receiver chains and associated channel conditions. The one or more UEs may then send an indication of the frequency domain imbalance estimation to the network entity. The network entity may then use the frequency domain imbalance estimation to perform a correction or elimination process on one or more of its plurality of transmission chains, which may reduce or eliminate frequency domain imbalance for some or all devices (such as one or more UEs) communicating with the network entity.

[0028] Certain aspects of the subject matter described in the present disclosure may be implemented to achieve one or more of the following potential advantages. The cost and complexity of network entity operations for correcting or eliminating frequency domain imbalance may be reduced because the UE will estimate the frequency domain imbalance of the corresponding transmission chain, rather than the network entity being burdened with calculating such imbalance for all of its transmission chains. In addition, as a result of receiving multiple estimates derived from transmissions received from the network entity through the corresponding transmission chains and associated channel conditions from multiple UEs, the accuracy of frequency domain imbalance estimates may be improved. In addition, other UEs that are not participating in the mismatch correction process may also benefit from corrections performed by the network entity even though the other UEs have not yet participated in the process, because the network entity may perform corrections on transmission chains corresponding to devices that did not contribute to frequency domain imbalance estimates (such as other UEs).

[0029] Various aspects of the present disclosure are first described in the context of a wireless communication system. Then, various aspects of the present disclosure are described with reference to wireless communication systems and process flows. Various aspects of the present disclosure are further illustrated and described with reference to device diagrams, system diagrams, and flow diagrams related to frequency domain imbalance correction.

[0030] Figure 1 An example of a wireless communication system 100 supporting frequency domain imbalance correction according to one or more examples as disclosed herein is illustrated. The wireless communication system 100 may include one or more network entities 105, one or more UEs 115, and a core network 130. In some examples, the wireless communication system 100 may be a Long Term Evolution (LTE) network, an Advanced LTE (LTE-A) network, an LTE-A Pro network, a New Radio (NR) network, or a network operating according to other systems and radio technologies including future systems and radio technologies not explicitly mentioned herein.

[0031] The network entities 105 may be dispersed throughout a geographic area to form the wireless communication system 100, and may include devices in different forms or with different capabilities. In various examples, the network entities 105 may be referred to as network elements, mobility elements, radio access network (RAN) nodes, or network equipment, among other nomenclature. In some examples, the network entities 105 and the UE 115 may communicate wirelessly via one or more communication links 125 (e.g., radio frequency (RF) access links). For example, the network entity 105 may support a coverage area 110 (e.g., a geographic coverage area), over which the UE 115 and the network entity 105 may establish one or more communication links 125. The coverage area 110 may be an example of a geographic area in which the network entity 105 and the UE 115 may support signal communications according to one or more radio access technologies (RATs).

[0032] The UEs 115 may be dispersed throughout the coverage area 110 of the wireless communication system 100, and each UE 115 may be stationary or mobile, or stationary and mobile at different times. The UEs 115 may be devices in different forms or with different capabilities. Figure 1 Some example UEs 115 are illustrated in FIG. 1 . The UEs 115 described herein may be capable of supporting communication with various types of devices, such as Figure 1 Communicate with other UEs 115 or network entities 105 as shown.

[0033] As described herein, a node of the wireless communication system 100 (which may be referred to as a network node or a wireless node) may be a network entity 105 (e.g., any network entity described herein), a UE 115 (e.g., any UE described herein), a network controller, an apparatus, a device, a computing system, one or more components, or another suitable processing entity configured to perform any of the techniques described herein. For example, the node may be a UE 115. As another example, the node may be a network entity 105. As another example, a first node may be configured to communicate with a second node or a third node. In one aspect of this example, the first node may be a UE 115, the second node may be a network entity 105, and the third node may be a UE 115. In another aspect of this example, the first node may be a UE 115, the second node may be a network entity 105, and the third node may be a network entity 105. In other aspects of this example, the first node, the second node, and the third node may be different relative to these examples. Similarly, references to UE 115, network entity 105, apparatus, device, computing system, etc. may include disclosure of UE 115, network entity 105, apparatus, device, computing system, etc. as nodes. For example, a disclosure that UE 115 is configured to receive information from network entity 105 also discloses that the first node is configured to receive information from a second node.

[0034] In some examples, the network entities 105 may communicate with the core network 130, or with each other, or both. For example, the network entities 105 may communicate with the core network 130 via one or more backhaul communication links 120 (e.g., according to S1, N2, N3, or other interface protocols). In some examples, the network entities 105 may communicate with each other directly (e.g., directly between the network entities 105) or indirectly (e.g., via the core network 130) via the backhaul communication links 120 (e.g., according to X2, Xn, or other interface protocols). In some examples, the network entities 105 may communicate with each other via midhaul communication links 162 (e.g., according to a midhaul interface protocol) or fronthaul communication links 168 (e.g., according to a fronthaul interface protocol) or any combination thereof. The backhaul communication links 120, midhaul communication links 162, or fronthaul communication links 168 may be or include one or more wired links (e.g., electrical links, optical fiber links), one or more wireless links (e.g., radio links, wireless optical links), etc. or various combinations thereof. UE 115 may communicate with core network 130 via communication link 155 .

[0035] One or more of the network entities 105 described herein may include or may be referred to as a base station 140 (e.g., a transceiver base station, a radio base station, an NR base station, an access point, a radio transceiver, a NodeB, an eNodeB (eNB), a next generation NodeB, or a giga NodeB (any of which may be referred to as a gNB), a 5G NB, a next generation eNB (ng-eNB), a Home NodeB, a Home eNodeB, or other suitable terminology). In some examples, the network entity 105 (e.g., a base station 140) may be implemented in a converged (e.g., monolithic, standalone) base station architecture that may be configured to utilize a protocol stack that is physically or logically integrated within a single network entity 105 (e.g., a single RAN node, such as a base station 140).

[0036] In some examples, the network entity 105 can be implemented in a disaggregated architecture (e.g., a disaggregated base station architecture, a disaggregated RAN architecture) that can be configured to utilize a protocol stack that is physically or logically distributed between two or more network entities 105, such as an integrated access backhaul (IAB) network, an open RAN (O-RAN) (e.g., a network configuration sponsored by the O-RAN Alliance), or a virtualized RAN (vRAN) (e.g., a cloud RAN (C-RAN)). For example, the network entity 105 can include one or more of the following: a central unit (CU) 160, a distributed unit (DU) 165, a radio unit (RU) 170, a RAN intelligent controller (RIC) 175 (e.g., a near real-time RIC (near RT RIC), a non-real-time RIC (non-RT RIC)), a service management and orchestration (SMO) 180 system, or any combination thereof. The RU 170 may also be referred to as a radio head, a smart radio head, a remote radio head (RRH), a remote radio unit (RRU), or a transmit receive point (TRP). One or more components of the network entity 105 in the decomposed RAN architecture may be co-located, or one or more components of the network entity 105 may be located in distributed locations (e.g., separate physical locations). In some examples, one or more network entities 105 of the decomposed RAN architecture may be implemented as virtual units (e.g., virtual CU (VCU), virtual DU (VDU), virtual RU (VRU)).

[0037] The functional split between CU 160, DU 165, and RU 170 is flexible and may support different functionalities depending on which functions (e.g., network layer functions, protocol layer functions, baseband functions, RF functions, and any combination thereof) are performed at CU 160, DU 165, and RU 170. For example, a functional split of a protocol stack may be employed between CU 160 and DU 165 such that CU 160 may support one or more layers of a protocol stack and DU 165 may support one or more different layers of a protocol stack. In some examples, CU 160 may host higher protocol layer (e.g., layer 3 (L3), layer 2 (L2)) functionality and signaling (e.g., radio resource control (RRC), service data adaptation protocol (SDAP), packet data convergence protocol (PDCP)). The CU 160 may be connected to one or more DUs 165 or RUs 170, and the one or more DUs 165 or RUs 170 may host lower protocol layers, such as layer 1 (L1) (e.g., physical (PHY) layer) or L2 (e.g., radio link control (RLC) layer, medium access control (MAC) layer) functionality and signaling, and may each be at least partially controlled by the CU 160. Additionally or alternatively, a functional split of the protocol stack may be employed between the DU 165 and the RU 170, such that the DU 165 may support one or more layers of the protocol stack, and the RU 170 may support one or more different layers of the protocol stack. The DU 165 may support one or more different cells (e.g., via one or more RUs 170). In some cases, the functional split between CU 160 and DU 165 or between DU 165 and RU 170 may be within the protocol layer (e.g., some functions of the protocol layer may be performed by one of CU 160, DU 165, or RU 170, while other functions of the protocol layer are performed by the other of CU 160, DU 165, or RU 170). CU 160 may be further functionally split into CU control plane (CU-CP) and CU user plane (CU-UP) functions. CU 160 may be connected to one or more DUs 165 via midhaul communication links 162 (e.g., F1, F1-c, F1-u), and DU 165 may be connected to one or more RUs 170 via fronthaul communication links 168 (e.g., open fronthaul (FH) interface). In some examples, midhaul communication link 162 or fronthaul communication link 168 may be implemented according to an interface (eg, a channel) between layers of a protocol stack supported by respective network entities 105 communicating via such communication links.

[0038] In some wireless communication systems (e.g., wireless communication system 100), infrastructure and spectrum resources for radio access may support wireless backhaul link capabilities to supplement wired backhaul connections, thereby providing an IAB network architecture (e.g., to the core network 130). In some cases, in an IAB network, one or more network entities 105 (e.g., IAB nodes 104) may be partially controlled by each other. One or more IAB nodes 104 may be referred to as donor entities or IAB donors. One or more DUs 165 or one or more RUs 170 may be partially controlled by one or more CUs 160 associated with a host network entity 105 (e.g., a host base station 140). One or more host network entities 105 (e.g., IAB hosts) may communicate with one or more additional network entities 105 (e.g., IAB nodes 104) via supported access and backhaul links (e.g., backhaul communication links 120). The IAB node 104 may include an IAB mobile terminal (IAB-MT) controlled (e.g., scheduled) by the DU 165 of the coupled IAB host. The IAB-MT may include an independent set of antennas for relaying communications with the UE 115, or may share the same antennas of the IAB node 104 (e.g., of the RU 170) for access via the DU 165 of the IAB node 104 (e.g., referred to as a virtual IAB-MT (vIAB-MT)). In some examples, the IAB node 104 may include a DU 165 that supports communication links with additional entities (e.g., IAB node 104, UE 115) within a relay chain or configuration (e.g., downstream) of the access network. In such cases, one or more components of the decomposed RAN architecture (e.g., one or more IAB nodes 104 or components of the IAB node 104) may be configured to operate according to the techniques described herein.

[0039] For example, an access network (AN) or RAN may include an access node (e.g., an IAB host), communications between an IAB node 104, and one or more UEs 115. The IAB host may facilitate a connection between the core network 130 and the AN (e.g., via a wired or wireless connection to the core network 130). That is, the IAB donor may refer to a RAN node having a wired or wireless connection to the core network 130. The IAB host may include a CU 160 and at least one DU 165 (e.g., and RU 170), in which case the CU 160 may communicate with the core network 130 via an interface (e.g., a backhaul link). The IAB host and the IAB node 104 may communicate via an F1 interface according to a protocol defining a signaling message (e.g., an F1 AP protocol). Additionally or alternatively, CU 160 may communicate with the core network via an interface (which may be an example of part of a backhaul link) and may communicate with other CUs 160 (e.g., CUs 160 associated with alternative IAB hosts) via an Xn-C interface (which may be an example of part of a backhaul link).

[0040] An IAB node 104 may refer to a RAN node that provides IAB functionality (e.g., access for UE 115, wireless self-backhaul capabilities, etc.). DU 165 may act as a distributed scheduling node toward child nodes associated with IAB node 104, and IAB-MT may act as a scheduled node toward a parent node associated with IAB node 104. That is, an IAB host may be referred to as a parent node that communicates with one or more child nodes (e.g., an IAB host may relay transmissions for UEs through one or more other IAB nodes 104). Additionally or alternatively, depending on the relay chain or configuration of the AN, an IAB node 104 may also be referred to as a parent node or child node of other IAB nodes 104. Thus, the IAB-MT entity of the IAB node 104 may provide a Uu interface for the child IAB node 104 to receive signaling from the parent IAB node 104 , and a DU interface (eg, DU 165 ) may provide a Uu interface for the parent IAB node 104 to signal to the child IAB node 104 or the UE 115 .

[0041] For example, the IAB node 104 may be referred to as a parent node supporting communications for a child IAB node or as a child IAB node associated with an IAB donor, or both. The IAB host may include a CU 160 having a wired or wireless connection (e.g., backhaul communication link 120) to the core network 130, and may act as a parent node of the IAB node 104. For example, the DU 165 of the IAB donor may relay the transmission to the UE 115 through the IAB node 104, or may directly signal the transmission to the UE 115, or both. The CU 160 of the IAB host may signal the establishment of a communication link to the IAB node 104 via the F1 interface, and the IAB node 104 may schedule the transmission (e.g., the transmission relayed from the IAB host to the UE 115) via the DU 165. That is, data may be relayed to and from the IAB node 104 via signaling via the NR Uu interface of the MT to the IAB node 104. Communications with the IAB node 104 may be scheduled by the DU 165 of the IAB donor, and communications with the IAB node 104 may be scheduled by the DU 165 of the IAB node 104 .

[0042] In the case where the techniques described herein are applied to the context of a decomposed RAN architecture, one or more components of the decomposed RAN architecture may be configured to support frequency domain imbalance correction as described herein. For example, some operations described as being performed by a UE 115 or a network entity 105 (e.g., a base station 140) may be additionally or alternatively performed by one or more components of the decomposed RAN architecture (e.g., an IAB node 104, a DU 165, a CU 160, a RU 170, a RIC 175, a SMO 180).

[0043] UE 115 may include or may be referred to as a mobile device, a wireless device, a remote device, a handheld device, or a subscriber device, or some other suitable term, where a "device" may also be referred to as a unit, a station, a terminal, or a client, etc. UE 115 may also include or may be referred to as a personal electronic device, such as a cellular phone, a personal digital assistant (PDA), a tablet computer, a laptop computer, or a personal computer. In some examples, UE 115 may include or may be referred to as a wireless local loop (WLL) station, an Internet of Things (IoT) device, an Internet of Everything (IoE) device, or a machine type communication (MTC) device, etc., which may be implemented in various objects such as appliances or vehicles, meters, etc.

[0044] The UE 115 described herein is capable of communicating with various types of devices, such as other UEs 115 that may sometimes act as relays, as well as network entities 105 and network equipment including macro eNBs or gNBs, small cell eNBs or gNBs, relay base stations, etc. Figure 1 as shown in .

[0045] The UE 115 and the network entity 105 may wirelessly communicate with each other via one or more communication links 125 (e.g., access links) using resources associated with one or more carriers. The term "carrier" may refer to a collection of RF spectrum resources having a physical layer structure defined for supporting the communication link 125. For example, a carrier for the communication link 125 may include a portion of an RF spectrum band (e.g., a bandwidth portion (BWP)) that operates according to one or more physical layer channels for a given radio access technology (e.g., LTE, LTE-A, LTE-A Pro, NR). Each physical layer channel may carry acquisition signaling (e.g., synchronization signals, system information), control signaling for coordinating carrier operations, user data, or other signaling. The wireless communication system 100 may support communications with the UE 115 using carrier aggregation or multi-carrier operation. Depending on the carrier aggregation configuration, the UE 115 may be configured with multiple downlink component carriers and one or more uplink component carriers. Carrier aggregation may be used for both frequency division duplex (FDD) and time division duplex (TDD) component carriers. Communication between the network entity 105 and other devices may refer to communication between the device and any portion (e.g., entity, sub-entity) of the network entity 105. For example, the terms "sending," "receiving," or "communicating" when referring to the network entity 105 may refer to any portion of the network entity 105 (e.g., base station 140, CU 160, DU 165, RU 170) of the RAN communicating with another device (e.g., directly or via one or more other network entities 105).

[0046] In some examples, such as in a carrier aggregation configuration, a carrier may also have acquisition signaling or control signaling that coordinates the operation of other carriers. A carrier may be associated with a frequency channel (e.g., an Evolved Universal Mobile Telecommunications System Terrestrial Radio Access (E-UTRA) Absolute RF Channel Number (EARFCN)) and may be identified according to a channel raster for discovery by UE 115. A carrier may operate in a standalone mode, in which case initial acquisition and connection may be performed by UE 115 via the carrier, or a carrier may operate in a non-standalone mode, in which case the connection is anchored using a different carrier (e.g., a different carrier of the same or different radio access technology).

[0047] The communication link 125 shown in the wireless communication system 100 may include downlink transmissions (e.g., forward link transmissions) from the network entity 105 to the UE 115, uplink transmissions (e.g., return link transmissions) from the UE 115 to the network entity 105, or both, as well as other transmission configurations. A carrier may carry either downlink or uplink communications (e.g., in an FDD mode), or may be configured to carry both downlink and uplink communications (e.g., in a TDD mode).

[0048] A carrier may be associated with a particular bandwidth of the RF spectrum, and in some examples, the carrier bandwidth may be referred to as a "system bandwidth" of the carrier or wireless communication system 100. For example, the carrier bandwidth may be one of a set of bandwidths of carriers for a particular radio access technology (e.g., 1.4 megahertz (MHz), 3 MHz, 5 MHz, 10 MHz, 15 MHz, 20 MHz, 40 MHz, or 80 MHz). Devices of the wireless communication system 100 (e.g., the network entity 105, the UE 115, or both) may have a hardware configuration that supports communication using a particular carrier bandwidth, or may be configured to support communication using one of the carrier bandwidths in the set of carrier bandwidths. In some examples, the wireless communication system 100 may include a network entity 105 or a UE 115 that supports concurrent communication using carriers associated with multiple carrier bandwidths. In some examples, each served UE 115 may be configured to operate using a portion (e.g., a subband, a BWP) or all of the carrier bandwidth.

[0049] The signal waveform transmitted via the carrier may be composed of multiple subcarriers (e.g., using multi-carrier modulation (MCM) techniques, such as orthogonal frequency division multiplexing (OFDM) or discrete Fourier transform spread OFDM (DFT-S-OFDM)). In a system using MCM technology, a resource element may refer to a resource of one symbol period (e.g., the duration of one modulation symbol) and one subcarrier, in which case the symbol period and the subcarrier spacing may be inversely related. The number of bits carried by each resource element may depend on the modulation scheme (e.g., the order of the modulation scheme, the coding rate of the modulation scheme, or both), so that a relatively high number of resource elements (e.g., in the transmission duration) and a relatively high order modulation scheme may correspond to a relatively high communication rate. Wireless communication resources may refer to a combination of RF spectrum resources, time resources, and spatial resources (e.g., spatial layers, beams), and the use of multiple spatial resources may increase the data rate or data integrity of communications with UE 115.

[0050] One or more parameter sets for a carrier may be supported, and a parameter set may include a subcarrier spacing ( ) and cyclic prefix. A carrier may be divided into one or more BWPs with the same or different parameter sets. In some examples, a UE 115 may be configured with multiple BWPs. In some examples, a single BWP of a carrier may be active at a given time, and communications for a UE 115 may be constrained to one or more active BWPs.

[0051] The time interval for the network entity 105 or the UE 115 may be expressed as a multiple of a basic time unit, which may be, for example, a sampling period. Seconds, for this can represent the supported subcarrier spacing, and The supported discrete Fourier transform (DFT) size may be indicated. Time intervals of communication resources may be organized according to radio frames, each having a specific duration (e.g., 10 milliseconds (ms)). Each radio frame may be identified by a system frame number (SFN) (e.g., ranging from 0 to 1023).

[0052] Each frame may include multiple consecutively numbered subframes or time slots, and each subframe or time slot may have the same duration. In some examples, a frame may be divided into subframes (e.g., in the time domain), and each subframe may be further divided into a certain number of time slots. Alternatively, each frame may include a variable number of time slots, and the number of time slots may depend on the subcarrier spacing. Each time slot may include multiple symbol periods (e.g., depending on the length of a cyclic prefix added before each symbol period). In some wireless communication systems 100, the time slot may be further divided into multiple micro-time slots associated with one or more symbols. Excluding the cyclic prefix, each symbol period may be associated with one or more (e.g., ) sampling period. The duration of a symbol period may depend on the subcarrier spacing or the operating frequency band.

[0053] A subframe, a time slot, a mini-time slot, or a symbol may be the smallest scheduling unit (e.g., in the time domain) of the wireless communication system 100 and may be referred to as a transmission time interval (TTI). In some examples, the TTI duration (e.g., the number of symbol periods in a TTI) may be variable. Additionally or alternatively, the smallest scheduling unit of the wireless communication system 100 may be dynamically selected (e.g., in the form of a burst of shortened TTIs (sTTIs)).

[0054] Physical channels may be multiplexed according to various techniques in order to communicate using a carrier. For example, physical control channels and physical data channels may be multiplexed using one or more of a time division multiplexing (TDM) technique, a frequency division multiplexing (FDM) technique, or a hybrid TDM-FDM technique to signal via a downlink carrier. A control region (e.g., a control resource set (CORESET)) for a physical control channel may be defined by a set of symbol periods and may extend across a system bandwidth or a subset of a system bandwidth of a carrier. One or more control regions (e.g., CORESETs) may be configured for a group of UEs 115. For example, one or more UEs in UE115 may monitor or search a control region for control information according to one or more search space sets, and each search space set may include one or more control channel candidates in one or more aggregation levels arranged in a cascaded manner. The aggregation level for a control channel candidate may refer to the amount of control channel resources (e.g., control channel elements (CCEs)) associated with coded information for a control information format having a given payload size. The search space sets may include a common search space set configured for transmitting control information to multiple UEs 115 , and a UE-specific search space set for transmitting control information to a specific UE 115 .

[0055] The network entity 105 may provide communication coverage via one or more cells (e.g., macro cells, small cells, hotspots, or other types of cells, or any combination thereof). The term "cell" may refer to a logical communication entity used to communicate with the network entity 105 (e.g., using a carrier), and may be associated with an identifier (e.g., a physical cell identifier (PCID), a virtual cell identifier (VCID), or other) used to distinguish adjacent cells. In some examples, a cell may also refer to a coverage area 110 or a portion of a coverage area 110 (e.g., a sector) on which a logical communication entity operates. Depending on various factors (such as the capabilities of the network entity 105), such cells may range from smaller areas (e.g., structures, subsets of structures) to larger areas. For example, a cell may be or may include a building, a subset of a building, or an external space between or overlapping coverage areas 110, and the like.

[0056] A macro cell typically covers a relatively large geographic area (e.g., a radius of several kilometers) and may allow unrestricted access to a UE 115 with a service subscription to a network provider that supports the macro cell. A small cell may be associated with a lower power network entity 105 (e.g., a lower power base station 140) than a macro cell, and the small cell may operate using the same or different (e.g., licensed, unlicensed) frequency band as the macro cell. A small cell may provide unrestricted access to a UE 115 with a service subscription to a network provider, or may provide restricted access to a UE 115 associated with a small cell (e.g., a UE 115 in a closed subscriber group (CSG), a UE 115 associated with a user in a home or office). A network entity 105 may support one or more cells, and may also use one or more component carriers to support communications via one or more cells.

[0057] In some examples, a carrier may support multiple cells, and different cells may be configured according to different protocol types (e.g., MTC, narrowband IoT (NB-IoT), enhanced mobile broadband (eMBB)) that may provide access to different types of devices.

[0058] In some examples, the network entities 105 (e.g., base stations 140, RUs 170) may be mobile and thus provide communication coverage for mobile coverage areas 110. In some examples, different coverage areas 110 associated with different technologies may overlap, but the different coverage areas 110 may be supported by the same network entity 105. In some other examples, overlapping coverage areas 110 associated with different technologies may be supported by different network entities 105. The wireless communication system 100 may include, for example, a heterogeneous network in which different types of network entities 105 provide coverage for various coverage areas 110 using the same or different radio access technologies.

[0059] The wireless communication system 100 may support synchronous or asynchronous operation. For synchronous operation, the network entities 105 (e.g., base stations 140) may have similar frame timing, and transmissions from different network entities 105 may be approximately aligned in time. For asynchronous operation, the network entities 105 may have different frame timing, and in some examples, transmissions from different network entities 105 may not be aligned in time. The techniques described herein may be used for synchronous or asynchronous operation.

[0060] Some UEs 115, such as MTC devices or IoT devices, may be low-cost or low-complexity devices and may provide automated communication between machines (e.g., via machine-to-machine (M2M) communication). M2M communication or MTC may refer to data communication technology that allows devices to communicate with each other or with a network entity 105 (e.g., base station 140) without human intervention. In some examples, M2M communication or MTC may include communication from devices that integrate sensors or meters to measure or capture information and relay such information to a central server or application that uses the information or presents the information to a person interacting with the application. Some UEs 115 may be designed to collect information or implement automated behavior of machines or other devices. Examples of applications for MTC devices include smart metering, inventory monitoring, water level monitoring, equipment monitoring, healthcare monitoring, wildlife monitoring, weather and geological event monitoring, fleet management and tracking, remote security sensing, physical access control, and transaction-based business charging.

[0061] Some UEs 115 may be configured to employ a reduced power consumption mode of operation, such as half-duplex communication (e.g., a mode that supports unidirectional communication via transmission or reception but does not support transmission and reception concurrently). In some examples, half-duplex communication may be performed with a reduced peak rate. Other power saving techniques for UEs 115 include entering a power saving deep sleep mode when not engaged in active communications, operating using limited bandwidth (e.g., according to narrowband communications), or a combination of these techniques. For example, some UEs 115 may be configured to operate using a narrowband protocol type that is associated with a defined portion or range (e.g., a subcarrier or resource block (RB) set) within a carrier, within a guard band of a carrier, or outside a carrier.

[0062] The wireless communication system 100 may be configured to support ultra-reliable communication or low-latency communication or various combinations thereof. For example, the wireless communication system 100 may be configured to support ultra-reliable low-latency communication (URLLC). The UE 115 may be designed to support ultra-reliable or low-latency or critical functions. Ultra-reliable communications may include private communications or group communications and may be supported by one or more services such as push-to-talk, video, or data. Support for ultra-reliable, low-latency functions may include prioritization of services, and such services may be used for public safety or general commercial applications. The terms ultra-reliable, low-latency, and ultra-reliable low-latency may be used interchangeably herein.

[0063] In some examples, the UE 115 may be configured to support communication directly with other UEs 115 via a device-to-device (D2D) communication link 135 (e.g., according to a peer-to-peer (P2P), D2D, or sidelink protocol). In some examples, one or more UEs 115 in a group that are performing D2D communication may be within a coverage area 110 of a network entity 105 (e.g., a base station 140, a RU 170), which may support aspects of such D2D communication configured (e.g., scheduled) by the network entity 105. In some examples, one or more UEs 115 in such a group may be outside of the coverage area 110 of the network entity 105, or may otherwise be unable or not configured to receive transmissions from the network entity 105. In some examples, a group of UEs 115 communicating via D2D communication may support a one-to-many (1:M) system in which each UE 115 transmits to each of the other UEs 115 in the group. In some examples, network entity 105 may facilitate scheduling of resources for D2D communications. In some other examples, D2D communications may be performed between UEs 115 without involving network entity 105.

[0064] In some systems, the D2D communication link 135 can be an example of a communication channel (such as a sidelink communication channel) between vehicles (e.g., UE 115). In some examples, the vehicles can communicate using vehicle-to-everything (V2X) communication, vehicle-to-vehicle (V2V) communication, or some combination of these items. The vehicles can signal information related to traffic conditions, signal scheduling, weather, safety, emergency situations, or any other information related to the V2X system. In some examples, vehicles in the V2X system can communicate with roadside infrastructure (such as roadside units), or communicate with the network via one or more network nodes (e.g., network entity 105, base station 140, RU170) using vehicle-to-network (V2N) communication, or both.

[0065] The core network 130 may provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. The core network 130 may be an evolved packet core (EPC) or a 5G core (5GC), and the EPC or 5GC may include at least one control plane entity (e.g., a mobility management entity (MME), an access and mobility management function (AMF)) that manages access and mobility, and at least one user plane entity (e.g., a serving gateway (S-GW), a packet data network (PDN) gateway (P-GW), or a user plane function (UPF)) that routes packets or interconnects to an external network. The control plane entity may manage non-access stratum (NAS) functions, such as mobility, authentication, and bearer management for UEs 115 served by network entities 105 (e.g., base stations 140) associated with the core network 130. User IP packets may be delivered through the user plane entity, which may provide IP address allocation and other functions. The user plane entity may be connected to the IP services 150 of one or more network operators. IP services 150 may include access to the Internet, an intranet, an IP Multimedia Subsystem (IMS), or packet-switched streaming services.

[0066] The wireless communication system 100 may operate using one or more frequency bands that may be in the range of 300 megahertz (MHz) to 300 gigahertz (GHz). Generally speaking, the region from 300 MHz to 3 GHz is referred to as the ultra-high frequency (UHF) region or decimeter band because the wavelengths range from about one decimeter to one meter in length. UHF waves may be blocked or redirected by buildings and environmental features (which may be referred to as clusters), but these waves may be sufficient to penetrate structures so that macro cells provide services to UEs 115 located indoors. Communications using UHF waves may be associated with smaller antennas and shorter distances (e.g., less than 100 kilometers) compared to communications using smaller frequencies and longer waves in the high frequency (HF) or very high frequency (VHF) portions of the spectrum below 300 MHz.

[0067] The wireless communication system 100 may also operate using a super high frequency (SHF) region (also known as a centimeter band) that may be in the range of 3 GHz to 30 GHz, or an extremely high frequency (EHF) region (also known as a millimeter band) of the spectrum (e.g., from 30 GHz to 300 GHz). In some examples, the wireless communication system 100 may support millimeter wave (mmW) communications between a UE 115 and a network entity 105 (e.g., a base station 140, a RU 170), and the EHF antennas of the corresponding devices may be smaller and closer than UHF antennas. In some examples, such techniques may facilitate the use of antenna arrays within a device. However, the propagation of EHF transmissions may have even greater attenuation and a shorter range than SHF or UHF transmissions. The techniques disclosed herein may be employed across transmissions using one or more different frequency regions, and the use of frequency bands specified across these frequency regions may vary by country or regulatory agency.

[0068] The wireless communication system 100 may utilize licensed and unlicensed RF spectrum bands. For example, the wireless communication system 100 may employ licensed assisted access (LAA), LTE unlicensed (LTE-U) radio access technology, or NR technology using unlicensed bands (such as the 5 GHz industrial, scientific, and medical (ISM) band). When operating using unlicensed RF spectrum bands, devices such as network entity 105 and UE 115 may employ carrier sensing for conflict detection and avoidance. In some examples, operations using unlicensed bands may be based on a carrier aggregation configuration combined with component carriers operating using licensed bands (e.g., LAA). Operations performed using unlicensed spectrum may include downlink transmissions, uplink transmissions, P2P transmissions, or D2D transmissions, among others.

[0069] The network entity 105 (e.g., base station 140, RU 170) or UE 115 may be equipped with multiple antennas that can be used to employ technologies such as transmit diversity, receive diversity, multiple-input multiple-output (MIMO) communication, or beamforming. The antennas of the network entity 105 or UE 115 may be located in one or more antenna arrays or antenna panels, which may support MIMO operations or transmit or receive beamforming. For example, one or more base station antennas or antenna arrays may be co-located at an antenna assembly, such as an antenna tower. In some examples, antennas or antenna arrays associated with the network entity 105 may be located at different geographical locations. The network entity 105 may include an antenna array having a set of antenna ports of multiple rows and columns that the network entity 105 can use to support beamforming for communications with the UE 115. Similarly, the UE 115 may include one or more antenna arrays that may support various MIMO or beamforming operations. Additionally or alternatively, the antenna panel may support RF beamforming for signals sent via the antenna ports.

[0070] The network entity 105 or the UE 115 may use MIMO communication to utilize multipath signal propagation and improve spectral efficiency by sending or receiving multiple signals via different spatial layers. Such a technology may be referred to as spatial multiplexing. The multiple signals may be sent, for example, by a transmitting device via different antennas or different combinations of antennas. Similarly, the multiple signals may be received by a receiving device via different antennas or different combinations of antennas. Each of the multiple signals may be referred to as a separate spatial stream and may carry information associated with the same data stream (e.g., the same codeword) or different data streams (e.g., different codewords). Different spatial layers may be associated with different antenna ports for channel measurement and reporting. MIMO technologies include single-user MIMO (SU-MIMO), for which multiple spatial layers are sent to the same receiving device; and multi-user MIMO (MU-MIMO), for which multiple spatial layers are sent to multiple devices.

[0071] Beamforming (which may also be referred to as spatial filtering, directional transmission, or directional reception) is a signal processing technique that may be used at a transmitting device or a receiving device (e.g., a network entity 105, a UE 115) to shape or steer an antenna beam (e.g., a transmit beam, a receive beam) along a spatial path between the transmitting device and the receiving device. Beamforming may be achieved by combining signals conveyed via antenna elements of an antenna array so that some signals propagating in a particular direction relative to the antenna array experience constructive interference, while other signals experience destructive interference. Adjustments to signals conveyed via antenna elements may include the transmitting device or the receiving device applying an amplitude offset, a phase offset, or both to signals carried via antenna elements associated with the device. Adjustments associated with each antenna element may be defined by a set of beamforming weights associated with a particular orientation (e.g., for an antenna array of a transmitting device or a receiving device, or for some other orientation).

[0072] The network entity 105 or the UE 115 may use beam scanning techniques as part of a beamforming operation. For example, the network entity 105 (e.g., base station 140, RU 170) may use multiple antennas or antenna arrays (e.g., antenna panels) to perform beamforming operations for directional communication with the UE 115. Some signals (e.g., synchronization signals, reference signals, beam selection signals, or other control signals) may be sent multiple times by the network entity 105 along different directions. For example, the network entity 105 may send signals according to different sets of beamforming weights associated with different transmission directions. Transmissions along different beam directions may be used to identify beam directions (e.g., by a transmitting device (such as the network entity 105) or by a receiving device (such as the UE 115)) for later transmission or reception by the network entity 105.

[0073] Some signals, such as data signals associated with a particular receiving device, may be transmitted by a transmitting device (e.g., transmitting network entity 105, transmitting UE 115) along a single beam direction (e.g., a direction associated with a receiving device (such as receiving network entity 105 or receiving UE 115)). In some examples, a beam direction associated with transmission along a single beam direction may be determined based on signals transmitted along one or more beam directions. For example, UE 115 may receive one or more of the signals sent by network entity 105 along different directions, and may report to network entity 105 an indication of the signal received by UE 115 with the highest signal quality or other acceptable signal quality.

[0074] In some examples, transmission by a device (e.g., by network entity 105 or UE 115) may be performed using multiple beam directions, and the device may use a combination of digital precoding or beamforming to generate a combined beam for transmission (e.g., from network entity 105 to UE 115). UE 115 may report feedback indicating precoding weights for one or more beam directions, and the feedback may correspond to a configured set of beams across a system bandwidth or one or more subbands. Network entity 105 may send a reference signal (e.g., a cell-specific reference signal (CRS), a channel state information reference signal (CSI-RS)), which may be precoded or non-precoded. UE 115 may provide feedback for beam selection, which may be a precoding matrix indicator (PMI) or codebook-based feedback (e.g., a multi-panel type codebook, a linear combination type codebook, a port selection type codebook). Although these techniques are described with reference to signals sent along one or more directions by a network entity 105 (e.g., base station 140, RU 170), UE 115 may use similar techniques to send signals multiple times along different directions (e.g., to identify a beam direction for subsequent transmission or reception by UE 115), or to send signals along a single direction (e.g., to send data to a receiving device).

[0075] A receiving device (e.g., UE 115) may perform receiving operations according to multiple receiving configurations (e.g., directional listening) when receiving various signals (such as synchronization signals, reference signals, beam selection signals, or other control signals) from a receiving device (e.g., network entity 105). For example, the receiving device may perform reception according to multiple receiving directions by receiving via different antenna subarrays, processing received signals according to different antenna subarrays, receiving according to different receiving beamforming weight sets (e.g., different directional listening weight sets) applied to signals received at multiple antenna elements of an antenna array, or processing received signals according to different receiving beamforming weight sets applied to signals received at multiple antenna elements of an antenna array, any of which may be referred to as "listening" according to different receiving configurations or receiving directions. In some examples, the receiving device may use a single receiving configuration to receive along a single beam direction (e.g., when receiving a data signal). A single receive configuration may be aligned along a beam direction determined based on listening according to different receive configuration directions (e.g., a beam direction determined to have the highest signal strength, highest signal-to-noise ratio (SNR), or other acceptable signal quality based on listening according to multiple beam directions).

[0076] The wireless communication system 100 may be a packet-based network that operates according to a layered protocol stack. In the user plane, communications at the bearer or PDCP layer may be IP-based. The RLC layer may perform packet segmentation and reassembly to communicate via logical channels. The MAC layer may perform priority processing and multiplexing of logical channels into transport channels. The MAC layer may also implement error detection techniques, error correction techniques, or both to support retransmission to improve link efficiency. In the control plane, the RRC layer may provide the establishment, configuration, and maintenance of an RRC connection that supports a radio bearer for user plane data between the UE 115 and the network entity 105 or the core network 130. The PHY layer may map a transport channel to a physical channel.

[0077] UE 115 and network entity 105 may support retransmission of data to increase the likelihood that the data is successfully received. Hybrid automatic repeat request (HARQ) feedback is a technique for increasing the likelihood of correctly receiving data via a communication link (e.g., communication link 125, D2D communication link 135). HARQ may include a combination of error detection (e.g., using a cyclic redundancy check (CRC)), forward error correction (FEC), and retransmission (e.g., automatic repeat request (ARQ)). HARQ may improve the throughput of the MAC layer in poor radio conditions (e.g., low signal-to-noise ratio conditions). In some examples, a device may support same-slot HARQ feedback, in which case the device may provide HARQ feedback in a specific time slot for data received via a previous symbol in the time slot. In some other examples, the device may provide HARQ feedback in a subsequent time slot or based on some other time interval.

[0078] In some implementations, the UE 115 may receive a reference signal from the network entity 105. The UE may determine an estimate of frequency domain imbalance between portions of the transmit chain of the network entity 105. The estimate may be based on the reference signal, a precoding matrix associated with the transmission from the network entity, and an estimate of channel conditions between the UE 115 and the network entity 105. The estimate may be generated by an iterative process in which the estimate of imbalance is compared to the actual imbalance until the difference between the estimate and the actual imbalance satisfies an estimate threshold. The UE 115 may send the estimate to the network entity 105, and the network entity 105 may perform an imbalance compensation operation to balance the frequency domain portion of the transmit chain (e.g., after the precoder but before the transmit modulator) based on the estimate of the frequency domain imbalance. The UE 115 may receive a data transmission from the network entity 105 that is sent through the corrected or balanced transmit chain of the network entity 105, thereby improving communication between the UE 115 and the network entity 105.

[0079] Figure 2An example of a wireless communication system 200 supporting frequency domain imbalance correction according to one or more examples as disclosed herein is illustrated. The wireless communication system 200 may include a network entity 105-a, which may be an example of one or more network entities discussed with respect to other figures. The wireless communication system 200 may include UEs 115-a, 115-b, which may be examples of UEs discussed with respect to other figures.

[0080] In some examples, UE 115-a, UE 115-b, or both may be located in a geographic coverage area 110-a that may be associated with network entity 105-a. Network entity 105-a and UE 115-a may communicate via one or more downlink communication links 205-a and one or more uplink communication links 205-b.

[0081] In some wireless communication systems, a network entity may employ the use of an IQ modulator that modulates the I and Q parts in a transmit chain. Such an IQ modulator may take as input data to be transmitted (e.g., data that has been processed by a pre-decoder), and may filter an unmodified version of the data using a first FDRSB filter, and filter a modified version of the data (e.g., a conjugated version of the data) using a second FDRSB filter. Each filter may include a gain component, a phase component, or both that may be adjusted by the network entity.

[0082] However, frequency domain imbalance (also referred to as IQ mismatch, IQ imbalance, frequency-dependent residual sideband (FDRSB)) can be an inherent impairment of IQ modulators (e.g., which can be used in MIMO or massive MIMO scenarios). Elimination, balancing or correction of frequency domain imbalance can be desirable because, without elimination, frequency domain imbalance can limit link performance.

[0083] In some specific implementations involving MIMO or massive MIMO, a network entity may use many antennas fed by many IQ modulators. However, the network entity may perform expensive and complex processes to estimate the numerous frequency domain imbalances present in the many IQ modulators of the many transmit chains used in the MIMO or massive MIMO scenarios. In addition, the network entity may dedicate hardware to such estimation of the frequency domain imbalances of the many IQ modulators. Such hardware may include an RF demodulator feedback chain, an analog-to-digital converter (ADC) for sampling, and hardware for digital frequency domain imbalance estimation.

[0084] Furthermore, in higher frequency bands (e.g., sub-THz bands), the number of transmit chains may be increased (e.g., compared to operation in other frequency bands) to achieve narrow beams that may compensate for path loss (e.g., due to high carrier frequencies). Therefore, correction of frequency domain imbalance in sub-THz bands for numerous IQ or transmit chains is both advantageous and challenging (e.g., due to the large number of parameters to be estimated for the numerous IQ or transmit chains).

[0085] However, to reduce such costs, the network entity 105-a may instead send a training or reference signal 220 to the UE 115-a, from which the UE 115-a may digitally estimate the frequency domain imbalance of some or all of the transmit chains of the network entity 105-a, thereby eliminating the need for additional RF hardware at the network entity 105-a. The UE 115-a may send the estimate to the network entity 105-a (e.g., in an imbalance estimate indication 225), and the network entity 105-a may use the estimate to calculate corrections to be made to one or more transmit chains at the network entity 105-a. The cost and complexity of the network entity 105-a from a frequency domain imbalance correction perspective is thereby greatly reduced. Furthermore, by having the network entity 105-a perform the correction (e.g., instead of applying frequency domain imbalance correction to each UE), all served UEs (e.g., even those UEs that do not contribute to frequency domain imbalance estimation or otherwise contribute to the frequency domain imbalance estimation process) are allowed to benefit from an improved communication link (e.g., a balanced communication link with reduced or eliminated frequency domain imbalance).

[0086] Therefore, network entity 105-a can correct frequency domain imbalance at network entity 105-a instead of at UE 115-a, allowing network entity 105-a to average estimated responses from all served UEs (e.g., UE 115-a and UE 115-b), thereby improving the accuracy of frequency domain imbalance correction.

[0087] In some such methods, the network entity 105-a may be assisted by one or more connected UEs (such as UE 115-a and UE 115-b) to obtain one or more estimates of frequency domain imbalance. Even without any estimation process, other UEs that may not participate in the estimation process may benefit from the correction. Such UEs may also enjoy reduced power consumption.

[0088] UE 115-a may determine the channel based on reference signal 220 (e.g., demodulation reference signal (DMRS)), estimated channel (e.g., ), a pre-decoder used at the network entity 105-a (e.g., represented by However, because this frequency domain imbalance occurs in the RF domain between the pre-decoder and the IQ modulator (which is located before the channel in the transmit chain), UE 115-a can use the information about the channel. and pre-decoder frequency domain imbalance can be performed solely based on the knowledge or information of the frequency domain.

[0089] For example, in some approaches, the channel estimation process may provide However, in the frequency domain imbalance estimation process, UE 115-a may estimate H alone instead of Thus, UE 115-a may receive the same pre-decoder as used at network entity 105-a. Additionally or alternatively, the network entity 105-a may signal a default, pre-agreed, or a priori precoder to the UE 115-a. may be used. In either case, UE 115-a receives information about a pre-decoder that network entity 105-a is using or will use for downlink transmissions to UE 115-a. Thus, after network entity 105-a sends an indication of the pre-decoder to UE 115-a, and after receiving a frequency domain imbalance estimate from UE 115-a, network entity 105-a may apply a correction to the transmit chain (e.g., after the pre-decoder and before the IQ modulator) and send a signal (e.g., data transmission 230) with reduced or eliminated frequency domain imbalance to all UEs it serves.

[0090] In some examples, UE 115-b may also perform one or more estimates of frequency domain imbalance and may send additional imbalance estimate indications 235 to network entity 105-a. Network entity 105-a may perform frequency domain imbalance correction based on some or all of the received frequency domain imbalance estimate indications (e.g., by averaging the estimates, optionally including weights of some or all of the estimate indications).

[0091] In some examples, the UE may perform one or more of the operations described herein (e.g., frequency domain imbalance estimation) at a rate or time specified by the network entity 105-a. For example, the network entity 105-a may send a timing indication 245 to the UE 115-a to indicate a schedule, timing, point in time, or other timing information to the UE 115-a, and the UE 115-a may perform the frequency domain imbalance estimation, send the imbalance estimation indication 225, or both based on the schedule, timing, point in time, or other timing information. By controlling the timing of the operations performed by the UE 115-a, the network entity 105-a may be able to track changes in frequency domain imbalance over time (e.g., due to temperature changes, aging, changing channel conditions, or one or more other factors).

[0092] Figure 3 An example of a wireless communication system 300 supporting frequency domain imbalance correction according to one or more examples as disclosed herein is illustrated. The wireless communication system 300 may include a network entity 105-b and one or more UEs 115-c communicating via a channel 345. The network entity 105-a may include a pre-decoder 325, one or more imbalance compensators 335, and one or more transmit (Tx) modulators 330.

[0093] UE 115-c may use A reference signal 340 (eg, DMRS) represented by The channel estimate 345 represented by The pre-decoder 320 represented by The UE 115-c can reconstruct the transmitted signal by using the reference signal 340 and the coefficients of the pre-decoder 320. UE 115-c may use one or more channel estimation methods to estimate the channel UE 115 - c may determine the channel based at least in part on the estimated channel. and reproduce the transmitted signal To estimate by Represents frequency domain imbalance.

[0094] It should be noted that channel estimation may similarly be subject to frequency domain imbalance. Therefore, UE 115-c may employ an iterative method for estimating frequency domain imbalance, wherein the channel is estimated using reference signal 340 impaired by frequency domain imbalance, the frequency domain imbalance may be corrected on the reference signal, and the channel estimation may be repeated on the reference signal 340. Such a process may be iteratively repeated to better improve the channel estimate, the frequency domain imbalance estimate, or both.

[0095] In some examples, the iterative method may include one or more of the following steps. In an example first step, UE 115-c may observe a signal received at UE 115-c, which may be Indicates that Indicates receiving signal, Indicates channel 345, Indicates sending data. represents the conjugated version of the sent data, indicates frequency domain imbalance, and Indicates the noise present in the signal.

[0096] In an example second step, UE 115-c may use one or more channel estimation methods to estimate the channel ,in ,in is a filter applied at the Tx modulator 330 to a non-conjugated version of the data to be transmitted.

[0097] In an example third step, UE 115-c may estimate frequency domain imbalance For example, UE 115-c goes through the process described in Equation 1, where is a filter applied at the Tx modulator 330 to a non-conjugated version of the data to be transmitted, is a filter applied at the Tx modulator 330 to a conjugate version of the data to be transmitted, and the other elements are as described herein. In some examples, the UE 115-c may estimate the frequency domain imbalance using least squares estimation, minimum mean square error estimation, or both. For example, the least squares estimation may be given by Represented by, and the minimum mean square error estimate can be obtained by express.

[0098]

[0099]

[0100]

[0101]

[0102]

[0103] In the example fourth step, UE 115-c may receive minus ,get .

[0104] In an example fifth step, the UE 115-c may determine whether the difference between the frequency domain imbalance and the frequency domain imbalance estimate satisfies an estimation threshold. For example, expressed as an equation, the UE 115-c may determine whether

[0105] ,in represents the threshold value, indicates frequency domain imbalance, and represents the frequency domain imbalance estimation.

[0106] If the difference does not satisfy the threshold, the process may iterate again. However, if the difference satisfies the threshold (e.g., the difference is less than the threshold), the process may end (e.g., because the frequency domain imbalance estimate is close enough to the actual frequency domain imbalance to be used for frequency domain imbalance correction at the network entity 105-b).

[0107] The UE 115-c may send one or more frequency domain imbalance coefficients to the network entity 105-b to indicate the frequency domain imbalance estimate. In some examples, the frequency domain imbalance coefficients may be transmitted with a certain resolution. For example, instead of sending a complete set of coefficients (e.g., 4096 coefficients), the UE 115-c may send The network entity 105 - c may interpolate the received coefficients to recover the complete set of coefficients.

[0108] In some examples, the network entity 105-b may receive frequency domain imbalance estimates from multiple UEs 115-c and may average them together. In some examples, the network entity 105-b may take a weighted average, assigning a weight to each estimate based on one or more factors including different channel conditions. In some such cases, the UE 115-c may send a channel quality metric or measurement (e.g., a signal-to-noise ratio (SNR)) to the network entity 105-b to assist in the weighting process at the network entity 105-b.

[0109] The network entity 105-b may apply imbalance compensation 335 to one or more transmit chains used by the network entity 105-b, which may be based on one or more received frequency domain imbalance estimates. In some examples, such imbalance compensation 335 may be expressed as

[0110]

[0111] The network entity 105 - b may then send data transmissions to the UEs 115 - c using imbalance compensation 335 to provide increased link quality to all served UEs 115 - c while reducing the processing burden on the network entity 105 - b .

[0112] Figure 4 An example of a process flow 400 for supporting frequency domain imbalance correction according to one or more examples as disclosed herein is illustrated. The process flow 400 can implement various aspects of the present disclosure described herein. The elements described in the process flow 400 (e.g., UE 115-d and network entity 105-c) can be examples of similarly named elements described herein.

[0113] In the following description of process flow 400, operations between various entities or elements may be performed in different orders or at different times. Some operations may also be excluded from process flow 400, or other operations may be added. Although various entities or elements are shown as performing operations of process flow 400, some aspects of some operations may also be performed by other entities or elements of process flow 400 or by entities or elements not depicted in the process flow, or any combination thereof.

[0114] At 420 , the UE 115 - d may receive a reference signal from the network entity 105 - c .

[0115] At 425, the UE 115-d may receive an indication of a precoding matrix from the network entity 105-c. Additionally or alternatively, the UE 115-d may receive an indication from the network entity 105-c that the UE 115-d is to estimate the frequency domain imbalance based at least in part on a default precoding matrix, wherein the precoding matrix is ​​a default precoding matrix.

[0116] At 430 , the UE 115 - d may receive an indication of a timing for generating an estimate of frequency domain imbalance.

[0117] At 435 , UE 115 - d may estimate a transmit signal associated with the data transmission, which may include a reference signal modified by a precoding matrix.

[0118] At 440, UE 115-d may perform an iterative frequency domain imbalance estimation process to generate an estimate of frequency domain imbalance based on satisfaction of the estimation threshold. In some examples, to perform the iterative frequency domain imbalance estimation process, UE 115-d may estimate channel conditions; estimate frequency domain imbalance based on the channel conditions and the estimated transmitted signal; apply compensation parameters to a reference signal; and determine whether a difference between the estimate of frequency domain imbalance and the frequency domain imbalance satisfies the estimation threshold. In some examples, the frequency domain imbalance is estimated by performing least squares estimation or minimum mean square error estimation or any combination thereof.

[0119] At 445, UE 115-d may send to network entity 105-c an indication of an estimate of frequency domain imbalance between an in-phase portion of a transmit chain of network entity 105-c and a quadrature-phase portion of a transmit chain of network entity 105-c, the estimate of frequency domain imbalance being based on a reference signal, a precoding matrix associated with transmissions from network entity 105-c, and an estimate of one or more channel conditions between the UE and network entity 105-c. In some examples, the estimate of frequency domain imbalance is sent according to timing.

[0120] At 450 , the UE 115 - d may receive a data transmission from the network entity 105 - c based on sending an indication of the estimate of the frequency domain imbalance.

[0121] Figure 5 An example of a process flow 500 supporting frequency domain imbalance correction according to one or more examples as disclosed herein is illustrated. The process flow 500 may implement aspects of the present disclosure described herein. The elements described in the process flow 500 may be examples of similarly named elements described herein.

[0122] In the following description of process flow 500, operations between various entities or elements may be performed in different orders or at different times. Some operations may also be excluded from process flow 500, or other operations may be added. Although various entities or elements are shown as performing operations of process flow 500, some aspects of some operations may also be performed by other entities or elements of process flow 500 or by entities or elements not depicted in the process flow, or any combination thereof.

[0123] At 520 , the network entity 105 - d may send a reference signal to a user equipment (UE) 115 - e .

[0124] At 525, the network entity 105-d may send an indication of the precoding matrix to the UE 115-e, and the precoding matrix is ​​applied in the transmit chain of the network entity. Additionally or alternatively, the network entity 105-d may send an indication to the UE 115-e that the UE 115-e is to estimate the frequency domain imbalance based at least in part on a default precoding matrix, wherein the precoding matrix is ​​a default precoding matrix.

[0125] At 530 , the network entity 105 - d may send an indication of a timing for generating an estimate of frequency domain imbalance.

[0126] At 535, network entity 105-d may receive an indication of a first estimate of frequency domain imbalance between an in-phase portion of a transmit chain of the network entity and a quadrature-phase portion of a transmit chain of the network entity, the first estimate based on a reference signal, a precoding matrix associated with transmissions from the network entity, and an estimate of a channel between UE 115-e and the network entity. In some examples, the indication of the first estimate of frequency domain imbalance is received according to timing.

[0127] At 540, the network entity 105-d may receive corresponding additional estimates of frequency domain imbalance from one or more other UEs, each corresponding additional estimate being based on a reference signal, a precoding matrix, and an estimate of a channel condition between the network entity and a corresponding additional UE in the one or more other UEs (e.g., UE 115-f).

[0128] At 545 , the network entity 105 - d may average the first estimate and the respective additional estimates by assigning a weight to each of the first estimate and the respective additional estimates based on the quality metric.

[0129] At 550, the network entity 105-d may perform an imbalance compensation operation of an in-phase portion and a quadrature-phase portion of a balanced transmit chain associated with a transmit chain of the network entity based on the first estimate of frequency domain imbalance. In some examples, the imbalance compensation operation may include applying the first estimate of frequency domain imbalance to a transmit signal associated with data transmission. In some examples, the imbalance compensation operation is performed based on an average of the first estimate and the corresponding additional estimate. In some examples, the imbalance compensation operation is performed after applying a precoding matrix and before modulating the in-phase portion and the quadrature-phase portion.

[0130] At 555, the network entity 105-d may send data to the UE 115-e based on performing the imbalance compensation operation.

[0131] Figure 6 A block diagram of a device 605 supporting frequency domain imbalance correction according to one or more examples as disclosed herein is illustrated. The device 605 may be an example of aspects of the UE 115 as described herein. The device 605 may include a receiver 610, a transmitter 615, and a communication manager 620. The communication manager 620 may be implemented at least in part by one or both of a modem and a processor. Each of these components may communicate with each other (e.g., via one or more buses).

[0132] The receiver 610 may provide means for receiving information (such as packets, user data, control information, or any combination thereof) associated with various information channels (e.g., control channels, data channels, information channels related to frequency domain imbalance correction). The information may be communicated to other components of the device 605. The receiver 610 may utilize a single antenna or a collection of multiple antennas.

[0133] The transmitter 615 may provide means for transmitting signals generated by other components of the device 605. For example, the transmitter 615 may transmit information (such as packets, user data, control information, or any combination thereof) associated with various information channels (e.g., control channels, data channels, information channels related to frequency domain imbalance correction). In some examples, the transmitter 615 may be co-located with the receiver 610 in a transceiver component. The transmitter 615 may utilize a single antenna or a collection of multiple antennas.

[0134] The communication manager 620, the receiver 610, the transmitter 615, or various combinations thereof, or various components thereof, may be examples of means for performing various aspects of frequency domain imbalance correction as described herein. For example, the communication manager 620, the receiver 610, the transmitter 615, or various combinations thereof, or components thereof, may support methods for performing one or more of the functions described herein.

[0135] In some examples, the communication manager 620, the receiver 610, the transmitter 615, or various combinations or components thereof may be implemented in hardware (e.g., in a communication management circuit). The hardware may include a processor, a digital signal processor (DSP), a central processing unit (CPU), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, a microcontroller, discrete gate or transistor logic components, discrete hardware components, or any combination thereof that is configured as or otherwise supports components for performing the functions described in the present disclosure. In some examples, the processor and a memory coupled to the processor may be configured to perform one or more functions described herein (e.g., by executing instructions stored in the memory by the processor).

[0136] Additionally or alternatively, in some examples, the communication manager 620, the receiver 610, the transmitter 615, or various combinations or components thereof may be implemented in code executed by a processor (e.g., as communication management software or firmware). If implemented in code executed by a processor, the functionality of the communication manager 620, the receiver 610, the transmitter 615, or various combinations or components thereof may be performed by a general purpose processor (e.g., configured as or otherwise supporting components for performing the functionality described in the present disclosure), a DSP, a CPU, an ASIC, an FPGA, a microcontroller, or any combination of these or other programmable logic devices.

[0137] In some examples, communication manager 620 may be configured to perform various operations (e.g., receive, obtain, monitor, output, transmit) using or otherwise cooperating with receiver 610, transmitter 615, or both. For example, communication manager 620 may receive information from receiver 610, transmit information to transmitter 615, or be integrated in conjunction with receiver 610, transmitter 615, or both to obtain information, output information, or perform various other operations as described herein.

[0138] Additionally or alternatively, according to examples as disclosed herein, the communication manager 620 may support wireless communications at the UE. For example, the communication manager 620 may be configured to or otherwise support components for receiving a reference signal from a network entity. The communication manager 620 may be configured to or otherwise support components for sending an indication of an estimate of a frequency domain imbalance between an in-phase portion of a reference signal and an orthogonal phase portion of a reference signal to the network entity based on a precoding matrix associated with the transmission from the network entity and an estimate of one or more channel conditions between the UE and the network entity. The communication manager 620 may be configured to or otherwise support components for receiving data transmissions from the network entity based on sending an indication of an estimate of the frequency domain imbalance.

[0139] By including or configuring a communication manager 620 according to examples as described herein, a device 605 (e.g., a processor controlling or otherwise coupled to a receiver 610, a transmitter 615, a communication manager 620, or a combination thereof) may support techniques for reducing processing, reducing power consumption, more efficiently utilizing communication resources, or any combination thereof.

[0140] Figure 7A block diagram of a device 705 supporting frequency domain imbalance correction according to one or more examples as disclosed herein is illustrated. The device 705 may be an example of aspects of the device 605 or UE 115 as described herein. The device 705 may include a receiver 710, a transmitter 715, and a communication manager 720. The communication manager 720 may be implemented at least in part by one or both of a modem and a processor. Each of these components may communicate with each other (e.g., via one or more buses).

[0141] The receiver 710 may provide means for receiving information (such as packets, user data, control information, or any combination thereof) associated with various information channels (e.g., control channels, data channels, information channels related to frequency domain imbalance correction). The information may be communicated to other components of the device 705. The receiver 710 may utilize a single antenna or a collection of multiple antennas.

[0142] The transmitter 715 may provide means for transmitting signals generated by other components of the device 705. For example, the transmitter 715 may transmit information (such as packets, user data, control information, or any combination thereof) associated with various information channels (e.g., control channels, data channels, information channels related to frequency domain imbalance correction). In some examples, the transmitter 715 may be co-located with the receiver 710 in a transceiver component. The transmitter 715 may utilize a single antenna or a collection of multiple antennas.

[0143] The device 705 or its various components may be examples of components for performing various aspects of frequency domain imbalance correction as described herein. For example, the communication manager 720 may include a reference signal component 725, an imbalance estimation component 730, a data transmission and reception component 735, or any combination thereof. In some examples, the communication manager 720 or its various components may be configured to use or otherwise cooperate with the receiver 710, the transmitter 715, or both to perform various operations (e.g., receive, obtain, monitor, output, transmit). For example, the communication manager 720 may receive information from the receiver 710, transmit information to the transmitter 715, or be integrated with the receiver 710, the transmitter 715, or both to obtain information, output information, or perform various other operations as described herein.

[0144] According to examples as disclosed herein, the communication manager 720 may support wireless communications at a UE. The reference signal component 725 may be configured to or otherwise support means for receiving a reference signal from a network entity. The imbalance estimation component 730 may be configured to or otherwise support means for sending to the network entity an indication of an estimate of a frequency domain imbalance between an in-phase portion of a reference signal and a quadrature-phase portion of the reference signal based on an estimate of a precoding matrix associated with a transmission from the network entity and one or more channel conditions between the UE and the network entity. The data transmission reception component 735 may be configured to or otherwise support means for receiving a data transmission from the network entity based on sending an indication of an estimate of a frequency domain imbalance.

[0145] Figure 8 A block diagram of a communication manager 820 supporting frequency domain imbalance correction according to one or more examples as disclosed herein is illustrated. The communication manager 820 or its various components may be examples of components for performing various aspects of frequency domain imbalance correction as described herein. For example, the communication manager 820 may include a reference signal component 825, an imbalance estimation component 830, a data transmission and reception component 835, a transmission signal estimation component 840, an iterative estimation processing component 845, a pre-decoding matrix component 850, an estimation timing component 855, or any combination thereof. Each of these components may communicate with each other directly or indirectly (e.g., via one or more buses).

[0146] Additionally or alternatively, according to examples as disclosed herein, the communication manager 820 may support wireless communications at the UE. The reference signal component 825 may be configured to or otherwise support components for receiving a reference signal from a network entity. The imbalance estimation component 830 may be configured to or otherwise support components for sending an indication of an estimate of a frequency domain imbalance between an in-phase portion of a reference signal and a quadrature-phase portion of a reference signal to the network entity based on an estimate of one or more channel conditions between the UE and the network entity and a precoding matrix associated with the transmission from the network entity. The data transmission reception component 835 may be configured to or otherwise support components for receiving a data transmission from the network entity based on sending an indication of the estimate of the frequency domain imbalance.

[0147] In some examples, the reference signal is affected by channel conditions and frequency domain imbalance, and the transmitted signal estimation component 840 can be configured as or otherwise supports components for estimating a transmitted signal associated with data transmission, the transmitted signal including the reference signal modified by the precoding matrix. In some examples, the reference signal is affected by channel conditions and frequency domain imbalance, and the iterative estimation process component 845 can be configured as or otherwise supports components for performing an iterative frequency domain imbalance estimation process that generates an estimate of the frequency domain imbalance based on satisfaction of an estimation threshold.

[0148] In some examples, to support the iterative frequency domain imbalance estimation process, the iterative estimation process component 845 may be configured to or otherwise support a component for estimating channel conditions. In some examples, to support the iterative frequency domain imbalance estimation process, the iterative estimation process component 845 may be configured to or otherwise support a component for estimating frequency domain imbalance based on channel conditions and a transmitted signal. In some examples, to support the iterative frequency domain imbalance estimation process, the iterative estimation process component 845 may be configured to or otherwise support a component for applying compensation parameters to a reference signal. In some examples, to support the iterative frequency domain imbalance estimation process, the iterative estimation process component 845 may be configured to or otherwise support a component for determining whether the difference between an estimate of frequency domain imbalance and the frequency domain imbalance satisfies an estimation threshold.

[0149] In some examples, the frequency domain imbalance is estimated by performing least squares estimation or minimum mean square error estimation or any combination thereof.

[0150] In some examples, precoding matrix component 850 may be configured or otherwise support means for receiving an indication of a precoding matrix from a network entity. In some examples, precoding matrix component 850 may be configured or otherwise support means for receiving an indication from a network entity that the UE is to estimate frequency domain imbalance based at least in part on a default precoding matrix, wherein the precoding matrix is ​​a default precoding matrix.

[0151] In some examples, estimate timing component 855 may be configured or otherwise support means for receiving an indication of a timing for generating an estimate of frequency domain imbalance. In some examples, estimate timing component 855 may be configured or otherwise support means for sending an estimate of frequency domain imbalance according to the timing.

[0152] Fig. 9A diagram of a system including a device 905 supporting frequency domain imbalance correction according to one or more examples as disclosed herein is illustrated. The device 905 may be an example of a device 605, a device 705, or a UE 115 as described herein, or include components thereof. The device 905 may communicate (e.g., wirelessly) with one or more network entities 105, one or more UEs 115, or any combination thereof. The device 905 may include components for two-way voice and data communications, including components for sending and receiving communications, such as a communication manager 920, an input / output (I / O) controller 910, a transceiver 915, an antenna 925, a memory 930, a code 935, and a processor 940. These components may be electronically communicated or otherwise coupled (e.g., operatively, communicatively, functionally, electronically, electrically) via one or more buses (e.g., a bus 945).

[0153] I / O controller 910 may manage input and output signals for device 905. I / O controller 910 may also manage peripheral devices that are not integrated into device 905. In some cases, I / O controller 910 may represent a physical connection or port to an external peripheral device. In some cases, I / O controller 910 may utilize an operating system such as iOS. ® ANDROID ® , MS-DOS ® 、MS-WINDOWS ® , OS / 2 ® ,UNIX ® 、LINUX ® or another known operating system. Additionally or alternatively, I / O controller 910 may represent or interact with a modem, keyboard, mouse, touch screen, or similar device. In some cases, I / O controller 910 may be implemented as part of a processor (such as processor 940). In some cases, a user may interact with device 905 via I / O controller 910 or via hardware components controlled by I / O controller 910.

[0154] In some cases, the device 905 may include a single antenna 925. However, in some other cases, the device 905 may have more than one antenna 925, which may be capable of concurrently transmitting or receiving multiple wireless transmissions. The transceiver 915 may communicate bidirectionally via one or more antennas 925, wired or wireless links, as described herein. For example, the transceiver 915 may represent a wireless transceiver and may communicate bidirectionally with another wireless transceiver. The transceiver 915 may also include a modem for: modulating packets; providing the modulated packets to one or more antennas 925 for transmission; and demodulating packets received from one or more antennas 925. The transceiver 915 or the transceiver 915 and one or more antennas 925 may be examples of transmitters 615, transmitters 715, receivers 610, receivers 710, or any combination thereof or components thereof as described herein.

[0155] The memory 930 may include random access memory (RAM) and read-only memory (ROM). The memory 930 may store computer-readable, computer-executable code 935 including instructions that, when executed by the processor 940, cause the device 905 to perform various functions described herein. The code 935 may be stored in a non-transitory computer-readable medium such as a system memory or another type of memory. In some cases, the code 935 may not be directly executable by the processor 940, but may (for example, when compiled and executed) cause the computer to perform the functions described herein. In some cases, the memory 930 may also include, among other things, a basic I / O system (BIOS) that may control basic hardware or software operations, such as interaction with peripheral components or devices.

[0156] The processor 940 may include an intelligent hardware device (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof). In some cases, the processor 940 may be configured to operate a memory array using a memory controller. In some other cases, the memory controller may be integrated into the processor 940. The processor 940 may be configured to execute computer-readable instructions stored in a memory (e.g., a memory 930) to cause the device 905 to perform various functions (e.g., functions or tasks that support frequency domain imbalance correction). For example, the device 905 or a component of the device 905 may include a processor 940 and a memory 930 coupled to or coupled to the processor 940, and the processor 940 and the memory 930 are configured to perform the various functions described herein.

[0157] Additionally or alternatively, according to examples as disclosed herein, the communication manager 920 may support wireless communications at the UE. For example, the communication manager 920 may be configured to or otherwise support a component for receiving a reference signal from a network entity. The communication manager 920 may be configured to or otherwise support a component for sending an indication of an estimate of a frequency domain imbalance between an in-phase portion of a reference signal and an orthogonal phase portion of a reference signal to the network entity based on a precoding matrix associated with the transmission from the network entity and an estimate of one or more channel conditions between the UE and the network entity. The communication manager 920 may be configured to or otherwise support a component for receiving a data transmission from the network entity based on sending an indication of an estimate of a frequency domain imbalance.

[0158] By including or configuring a communications manager 920 according to the examples described herein, the device 905 may support techniques for improving communications reliability, reducing latency, improving user experience associated with reduced processing, reducing power consumption, more efficiently utilizing communications resources, improving coordination between devices, extending battery life, improving utilization of processing power, or any combination thereof.

[0159] In some examples, the communication manager 920 may be configured to perform various operations (e.g., receive, monitor, transmit) using or otherwise cooperating with the transceiver 915, one or more antennas 925, or any combination thereof. Although the communication manager 920 is illustrated as a separate component, in some examples, one or more functions described with reference to the communication manager 920 may be supported or performed by the processor 940, the memory 930, the code 935, or any combination thereof. For example, the code 935 may include instructions executable by the processor 940 to cause the device 905 to perform various aspects of frequency domain imbalance correction as described herein, or the processor 940 and the memory 930 may be otherwise configured to perform or support such operations.

[0160] Fig.10 A block diagram of a device 1005 supporting frequency domain imbalance correction according to one or more examples as disclosed herein is illustrated. The device 1005 may be an example of aspects of the network entity 105 as described herein. The device 1005 may include a receiver 1010, a transmitter 1015, and a communication manager 1020. The communication manager 1020 may be implemented at least in part by one or both of a modem and a processor. Each of these components may communicate with each other (e.g., via one or more buses).

[0161] The receiver 1010 may provide means for obtaining (e.g., receiving, determining, identifying) information associated with various channels (e.g., control channels, data channels, information channels, channels associated with a protocol stack), such as user data, control information, or any combination thereof (e.g., I / Q samples, symbols, packets, protocol data units, service data units). The information may be communicated to other components of the device 1005. In some examples, the receiver 1010 may support obtaining information by receiving signals via one or more antennas. Additionally or alternatively, the receiver 1010 may support obtaining information by receiving signals via one or more wired (e.g., electrical, optical) interfaces, wireless interfaces, or any combination thereof.

[0162] The transmitter 1015 may provide means for outputting (e.g., transmitting, providing, conveying, transmitting) information generated by other components of the device 1005. For example, the transmitter 1015 may output information associated with various channels (e.g., control channels, data channels, information channels, channels associated with a protocol stack), such as user data, control information, or any combination thereof (e.g., I / Q samples, symbols, packets, protocol data units, service data units). In some examples, the transmitter 1015 may support outputting information by transmitting signals via one or more antennas. Additionally or alternatively, the transmitter 1015 may support outputting information by transmitting signals via one or more wired (e.g., electrical, optical) interfaces, wireless interfaces, or any combination thereof. In some examples, the transmitter 1015 and the receiver 1010 may be co-located in a transceiver, which may include a modem or be coupled to a modem.

[0163] The communication manager 1020, the receiver 1010, the transmitter 1015, or various combinations thereof, or various components thereof, may be examples of means for performing various aspects of frequency domain imbalance correction as described herein. For example, the communication manager 1020, the receiver 1010, the transmitter 1015, or various combinations thereof, or components thereof, may support methods for performing one or more of the functions described herein.

[0164] In some examples, the communication manager 1020, the receiver 1010, the transmitter 1015, or various combinations or components thereof may be implemented in hardware (e.g., in a communication management circuit). The hardware may include a processor, a DSP, a CPU, an ASIC, an FPGA or other programmable logic device, a microcontroller, discrete gate or transistor logic components, discrete hardware components, or any combination thereof that is configured as or otherwise supports components for performing the functions described in the present disclosure. In some examples, a processor and a memory coupled to the processor may be configured to perform one or more functions described herein (e.g., by executing instructions stored in the memory by the processor).

[0165] Additionally or alternatively, in some examples, the communication manager 1020, the receiver 1010, the transmitter 1015, or various combinations or components thereof may be implemented in code executed by a processor (e.g., as communication management software or firmware). If implemented in code executed by a processor, the functions of the communication manager 1020, the receiver 1010, the transmitter 1015, or various combinations or components thereof may be performed by a general purpose processor (e.g., configured as or otherwise supporting components for performing the functions described in the present disclosure), a DSP, a CPU, an ASIC, an FPGA, a microcontroller, or any combination of these or other programmable logic devices.

[0166] In some examples, communication manager 1020 may be configured to perform various operations (e.g., receive, obtain, monitor, output, transmit) using or otherwise cooperating with receiver 1010, transmitter 1015, or both. For example, communication manager 1020 may receive information from receiver 1010, transmit information to transmitter 1015, or be integrated in conjunction with receiver 1010, transmitter 1015, or both to obtain information, output information, or perform various other operations as described herein.

[0167] Additionally or alternatively, according to examples as disclosed herein, the communication manager 1020 may support wireless communications at a network entity. For example, the communication manager 1020 may be configured to or otherwise support a component for sending a reference signal to a UE. The communication manager 1020 may be configured to or otherwise support a component for receiving an indication of a first estimate of a frequency domain imbalance between an in-phase portion of a transmission chain of a network entity and a quadrature-phase portion of a transmission chain of the network entity, the first estimate being based on the reference signal, a precoding matrix associated with a transmission from the network entity, and an estimate of a channel between the UE and the network entity. The communication manager 1020 may be configured to or otherwise support a component for performing an imbalance compensation operation of an in-phase portion and a quadrature-phase portion of a balanced transmission chain associated with the transmission chain of the network entity based on the first estimate of the frequency domain imbalance. The communication manager 1020 may be configured to or otherwise support a component for sending data to the UE based on performing the imbalance compensation operation.

[0168] By including or configuring a communication manager 1020 according to examples as described herein, a device 1005 (e.g., a processor controlling or otherwise coupled to a receiver 1010, a transmitter 1015, a communication manager 1020, or a combination thereof) may support techniques for reducing processing, reducing power consumption, more efficiently utilizing communication resources, or any combination thereof.

[0169] Fig.11 A block diagram of a device 1105 supporting frequency domain imbalance correction according to one or more examples as disclosed herein is illustrated. The device 1105 may be an example of aspects of the device 1005 or the network entity 105 as described herein. The device 1105 may include a receiver 1110, a transmitter 1115, and a communication manager 1120. The communication manager 1120 may be implemented at least in part by one or both of a modem and a processor. Each of these components may communicate with each other (e.g., via one or more buses).

[0170] The receiver 1110 may provide means for obtaining (e.g., receiving, determining, identifying) information associated with various channels (e.g., control channels, data channels, information channels, channels associated with a protocol stack), such as user data, control information, or any combination thereof (e.g., I / Q samples, symbols, packets, protocol data units, service data units). The information may be communicated to other components of the device 1105. In some examples, the receiver 1110 may support obtaining information by receiving signals via one or more antennas. Additionally or alternatively, the receiver 1110 may support obtaining information by receiving signals via one or more wired (e.g., electrical, optical) interfaces, wireless interfaces, or any combination thereof.

[0171] The transmitter 1115 may provide means for outputting (e.g., transmitting, providing, conveying, transmitting) information generated by other components of the device 1105. For example, the transmitter 1115 may output information associated with various channels (e.g., control channels, data channels, information channels, channels associated with a protocol stack), such as user data, control information, or any combination thereof (e.g., I / Q samples, symbols, packets, protocol data units, service data units). In some examples, the transmitter 1115 may support outputting information by transmitting signals via one or more antennas. Additionally or alternatively, the transmitter 1115 may support outputting information by transmitting signals via one or more wired (e.g., electrical, optical) interfaces, wireless interfaces, or any combination thereof. In some examples, the transmitter 1115 and the receiver 1110 may be co-located in a transceiver, which may include a modem or be coupled to a modem.

[0172] The device 1105 or its various components may be examples of components for performing various aspects of frequency domain imbalance correction as described herein. For example, the communication manager 1120 may include a reference signal component 1125, an imbalance estimation component 1130, an imbalance compensation component 1135, a data transmission component 1140, or any combination thereof. In some examples, the communication manager 1120 or its various components may be configured to perform various operations (e.g., receive, obtain, monitor, output, transmit) using or otherwise cooperating with the receiver 1110, the transmitter 1115, or both. For example, the communication manager 1120 may receive information from the receiver 1110, transmit information to the transmitter 1115, or be integrated with the receiver 1110, the transmitter 1115, or both to obtain information, output information, or perform various other operations as described herein.

[0173] According to examples as disclosed herein, the communication manager 1120 may support wireless communications at a network entity. The reference signal component 1125 may be configured to or otherwise support components for sending a reference signal to a UE. The imbalance estimation component 1130 may be configured to or otherwise support components for receiving an indication of a first estimate of a frequency domain imbalance between an in-phase portion of a transmission chain of a network entity and a quadrature-phase portion of a transmission chain of the network entity, the first estimate being based on the reference signal, a pre-decoding matrix associated with a transmission from the network entity, and an estimate of a channel between the UE and the network entity. The imbalance compensation component 1135 may be configured to or otherwise support components for performing an imbalance compensation operation of an in-phase portion and a quadrature-phase portion of a balanced transmission chain associated with the transmission chain of the network entity based on the first estimate of the frequency domain imbalance. The data transmission component 1140 may be configured to or otherwise support components for transmitting data to the UE based on performing the imbalance compensation operation.

[0174] Fig.12 A block diagram of a communication manager 1220 supporting frequency domain imbalance correction according to one or more examples as disclosed herein is illustrated. The communication manager 1220 or its various components may be examples of components for performing various aspects of frequency domain imbalance correction as described herein. For example, the communication manager 1220 may include a reference signal component 1225, an imbalance estimation component 1230, an imbalance compensation component 1235, a data transmission component 1240, an average estimation component 1245, a pre-decoding matrix component 1250, an estimated timing component 1255, an estimated weighting component 1260, or any combination thereof. Each of these components may communicate with each other directly or indirectly (e.g., via one or more buses), and the communication may include communication within a protocol layer of a protocol stack, communication associated with a logical channel of a protocol stack (e.g., between protocol layers of a protocol stack, within a device, component, or virtualized component associated with a network entity 105, between devices, components, or virtualized components associated with a network entity 105), or any combination thereof.

[0175] Additionally or alternatively, according to examples as disclosed herein, the communication manager 1220 may support wireless communications at a network entity. The reference signal component 1225 may be configured to or otherwise support a component for sending a reference signal to a UE. The imbalance estimation component 1230 may be configured to or otherwise support a component for receiving an indication of a first estimate of a frequency domain imbalance between an in-phase portion of a transmission chain of a network entity and a quadrature-phase portion of a transmission chain of the network entity, the first estimate being based on the reference signal, a precoding matrix associated with a transmission from the network entity, and an estimate of a channel between the UE and the network entity. The imbalance compensation component 1235 may be configured to or otherwise support a component for performing an imbalance compensation operation of an in-phase portion and a quadrature-phase portion of a balanced transmission chain associated with the transmission chain of the network entity based on the first estimate of the frequency domain imbalance. The data transmission component 1240 may be configured to or otherwise support a component for transmitting data to the UE based on performing the imbalance compensation operation.

[0176] In some examples, the imbalance compensation operation includes applying a first estimate of frequency domain imbalance to a transmit signal associated with the data transmission.

[0177] In some examples, average estimation component 1245 can be configured as or otherwise support means for receiving respective additional estimates of frequency domain imbalance from one or more other UEs, each respective additional estimate being based on a reference signal, a precoding matrix, and an estimate of a channel condition between the network entity and a respective additional UE in the one or more other UEs. In some examples, average estimation component 1245 can be configured as or otherwise support means for performing an imbalance compensation operation based on an average of the first estimate and the respective additional estimates.

[0178] In some examples, the first estimate and the corresponding additional estimates are averaged by assigning a weight to each of the first estimate and the corresponding additional estimates based on a quality metric.

[0179] In some examples, precoding matrix component 1250 may be configured as or otherwise support means for sending an indication of a precoding matrix to a UE, wherein the precoding matrix is ​​applied in a transmit chain of a network entity. In some examples, precoding matrix component 1250 may be configured as or otherwise support means for sending an indication to a UE that the UE is to estimate frequency domain imbalance based at least in part on a default precoding matrix, wherein the precoding matrix is ​​a default precoding matrix.

[0180] In some examples, the imbalance compensation operation is performed after applying the precoding matrix and before modulating the in-phase portion and the quadrature-phase portion.

[0181] In some examples, estimate timing component 1255 can be configured or otherwise support means for sending an indication of a timing for generating an estimate of frequency domain imbalance. In some examples, estimate timing component 1255 can be configured or otherwise support means for receiving an indication of a first estimate of frequency domain imbalance according to the timing.

[0182] Fig.13A diagram of a system including a device 1305 supporting frequency domain imbalance correction according to one or more examples as disclosed herein is illustrated. The device 1305 may be an example of a device 1005, a device 1105, or a network entity 105 as described herein, or include components thereof. The device 1305 may communicate with one or more network entities 105, one or more UEs 115, or any combination thereof, which may include communication through one or more wired interfaces, through one or more wireless interfaces, or any combination thereof. The device 1305 may include components that support output and acquisition of communications, such as a communication manager 1320, a transceiver 1310, an antenna 1315, a memory 1325, a code 1330, and a processor 1335. These components may be electronically communicated or otherwise coupled (e.g., operatively, communicatively, functionally, electronically, electrically) via one or more buses (e.g., bus 1340).

[0183] The transceiver 1310 may support bidirectional communication via a wired link, a wireless link, or both as described herein. In some examples, the transceiver 1310 may include a wired transceiver and may communicate bidirectionally with another wired transceiver. Additionally or alternatively, in some examples, the transceiver 1310 may include a wireless transceiver and may communicate bidirectionally with another wireless transceiver. In some examples, the device 1305 may include one or more antennas 1315, which may be capable of (e.g., concurrently) sending or receiving wireless transmissions. The transceiver 1310 may also include a modem for: modulating a signal; providing the modulated signal for transmission (e.g., via one or more antennas 1315, via a wired transmitter); receiving the modulated signal (e.g., from one or more antennas 1315, from a wired receiver); and demodulating the signal. In some implementations, the transceiver 1310 may include one or more interfaces, such as one or more interfaces coupled to one or more antennas 1315 configured to support various receiving or obtaining operations, or one or more interfaces coupled to one or more antennas 1315 configured to support various transmitting or outputting operations, or a combination thereof. In some implementations, the transceiver 1310 may include or be configured to be coupled to one or more processors or memory components, which are operable to perform or support operations based on received or obtained information or signals, or to generate information or other signals for transmission or other output, or any combination thereof. In some implementations, the transceiver 1310, or the transceiver 1310 and one or more antennas 1315, or the transceiver 1310 and one or more antennas 1315 and one or more processors or memory components (e.g., processor 1335 or memory 1325 or both) may be included in a chip or chip assembly installed in the device 1305. In some examples, the transceiver may be operable to support communications via one or more communication links (eg, communication link 125 , backhaul communication link 120 , midhaul communication link 162 , fronthaul communication link 168 ).

[0184] Memory 1325 may include RAM and ROM. Memory 1325 may store computer-readable, computer-executable code 1330 including instructions that, when executed by processor 1335, cause device 1305 to perform various functions described herein. Code 1330 may be stored in a non-transitory computer-readable medium such as system memory or another type of memory. In some cases, code 1330 may not be directly executable by processor 1335, but may (e.g., when compiled and executed) cause a computer to perform the functions described herein. In some cases, memory 1325 may also contain, among other things, a BIOS that may control basic hardware or software operations, such as interaction with peripheral components or devices.

[0185] The processor 1335 may include an intelligent hardware device (e.g., a general-purpose processor, a DSP, an ASIC, a CPU, an FPGA, a microcontroller, a programmable logic device, a discrete gate or transistor logic, a discrete hardware component, or any combination thereof). In some cases, the processor 1335 may be configured to operate a memory array using a memory controller. In some other cases, the memory controller may be integrated into the processor 1335. The processor 1335 may be configured to execute computer-readable instructions stored in a memory (e.g., a memory 1325) to enable the device 1305 to perform various functions (e.g., functions or tasks supporting frequency domain imbalance correction). For example, the device 1305 or a component of the device 1305 may include a processor 1335 and a memory 1325 coupled to the processor 1335, and the processor 1335 and the memory 1325 are configured to perform various functions described herein. The processor 1335 may be an example of a cloud computing platform (e.g., one or more physical nodes and supporting software (such as an operating system, a virtual machine, or a container instance)), which may host functions (e.g., by executing code 1330) to perform the functions of the device 1305. The processor 1335 may be any one or more suitable processors capable of executing scripts or instructions of one or more software programs stored in the device 1305 (such as in the memory 1325). In some specific implementations, the processor 1335 may be a component of a processing system. A processing system may generally refer to a system or a series of machines or components that receive inputs and process these inputs to produce a set of outputs (which may be delivered to, for example, other systems or components of the device 1305). For example, the processing system of the device 1305 may refer to a system including various other components or subcomponents of the device 1305 (such as the processor 1335, or the transceiver 1310, or the communication manager 1320, or other components or combinations of components of the device 1305). The processing system of the device 1305 may interface with other components of the device 1305 and may process information (such as inputs or signals) received from other components or output information to other components. For example, a chip or modem of the device 1305 may include a processing system and one or more interfaces for outputting information or for obtaining information or both. One or more interfaces may be implemented as or otherwise include a first interface configured to output information and a second interface configured to obtain information or the same interface configured to output information and obtain information, as well as other specific implementations. In some specific implementations, one or more interfaces may refer to an interface between a processing system of a chip or modem and a transmitter, so that the device 1305 can send information output from the chip or modem. Additionally or alternatively, in some specific implementations, one or more interfaces may refer to an interface between a processing system of a chip or modem and a receiver, so that the device 1305 can obtain information or signal input, and the information can be passed to the processing system.One of ordinary skill in the art will readily recognize that the first interface may also obtain information or signal input, and the second interface may also output information or signal output.

[0186] In some examples, bus 1340 may support communications of protocol layers (e.g., within a protocol layer) of a protocol stack. In some examples, bus 1340 may support communications associated with logical channels of a protocol stack (e.g., between protocol layers of a protocol stack), which may include communications performed within a component of device 1305, or communications performed between different components of device 1305 that may be co-located or located in different locations (e.g., where device 1305 may refer to a system in which one or more of communication manager 1320, transceiver 1310, memory 1325, code 1330, and processor 1335 may be located in one of the different components or divided between the different components).

[0187] In some examples, the communication manager 1320 can manage aspects of communications with the core network 130 (e.g., via one or more wired or wireless backhaul links). For example, the communication manager 1320 can manage the delivery of data communications for client devices such as one or more UEs 115. In some examples, the communication manager 1320 can manage communications with other network entities 105 and can include a controller or scheduler for controlling communications with the UE 115 in coordination with the other network entities 105. In some examples, the communication manager 1320 can support an X2 interface within an LTE / LTE-A wireless communication network technology to provide communications between network entities 105.

[0188] Additionally or alternatively, according to examples as disclosed herein, the communication manager 1320 may support wireless communications at a network entity. For example, the communication manager 1320 may be configured to or otherwise support a component for sending a reference signal to a UE. The communication manager 1320 may be configured to or otherwise support a component for receiving an indication of a first estimate of a frequency domain imbalance between an in-phase portion of a transmission chain of a network entity and a quadrature phase portion of a transmission chain of the network entity, the first estimate being based on the reference signal, a precoding matrix associated with a transmission from the network entity, and an estimate of a channel between the UE and the network entity. The communication manager 1320 may be configured to or otherwise support a component for performing an imbalance compensation operation of an in-phase portion and a quadrature phase portion of a balanced transmission chain associated with the transmission chain of the network entity based on the first estimate of the frequency domain imbalance. The communication manager 1320 may be configured to or otherwise support a component for sending data to the UE based on performing the imbalance compensation operation.

[0189] By including or configuring a communications manager 1320 according to the examples described herein, the device 1305 may support techniques for improving communications reliability, reducing latency, improving user experience associated with reduced processing, reducing power consumption, more efficiently utilizing communications resources, improving coordination between devices, extending battery life, improving utilization of processing power, or any combination thereof.

[0190] In some examples, the communication manager 1320 may be configured to perform various operations (e.g., receive, obtain, monitor, output, transmit) using or otherwise cooperating with the transceiver 1310, one or more antennas 1315 (e.g., where applicable), or any combination thereof. Although the communication manager 1320 is illustrated as a separate component, in some examples, one or more functions described with reference to the communication manager 1320 may be supported or performed by the transceiver 1310, the processor 1335, the memory 1325, the code 1330, or any combination thereof. For example, the code 1330 may include instructions executable by the processor 1335 to cause the device 1305 to perform various aspects of frequency domain imbalance correction as described herein, or the processor 1335 and the memory 1325 may be otherwise configured to perform or support such operations.

[0191] Fig.14 A flowchart illustrating a method 1400 for supporting frequency domain imbalance correction according to one or more examples disclosed herein is illustrated. The operations of the method 1400 may be implemented by a UE or a component thereof as described herein. For example, the operations of the method 1400 may be implemented by a UE or a component thereof as described herein. Figures 1 to 9 The UE 115 described herein may be executed. In some examples, the UE may execute an instruction set to control the functional elements of the UE to perform the described functions. Additionally or alternatively, the UE may use dedicated hardware to perform various aspects of the described functions.

[0192] At 1405, the method may include receiving a reference signal from a network entity. The operations of 1405 may be performed according to examples as disclosed herein. In some examples, aspects of the operations of 1405 may be performed by Figure 8 The reference signal component 825 is used to perform the above.

[0193] At 1410, the method may include sending to the network entity an indication of an estimate of a frequency domain imbalance between an in-phase portion of a reference signal and a quadrature-phase portion of the reference signal based on a precoding matrix associated with a transmission from the network entity and an estimate of one or more channel conditions between the UE and the network entity. The operations of 1410 may be performed according to examples as disclosed herein. In some examples, aspects of the operations of 1410 may be performed by Figure 8 The imbalance estimation component 830 is used to perform the above operation.

[0194] At 1415, the method may include receiving a data transmission from a network entity based on transmitting an indication of an estimate of frequency domain imbalance. The operations of 1415 may be performed according to examples as disclosed herein. In some examples, aspects of the operations of 1415 may be performed as described in reference to Figure 8 The data sending and receiving component 835 is used to execute.

[0195] Fig.15 A flowchart illustrating a method 1500 for supporting frequency domain imbalance correction according to one or more examples disclosed herein is illustrated. The operations of the method 1500 may be implemented by a UE or a component thereof as described herein. For example, the operations of the method 1500 may be implemented by a UE or a component thereof as described herein. Figures 1 to 9 The UE 115 described herein may be executed. In some examples, the UE may execute an instruction set to control the functional elements of the UE to perform the described functions. Additionally or alternatively, the UE may use dedicated hardware to perform various aspects of the described functions.

[0196] At 1505, the method may include receiving a reference signal from a network entity. The operations of 1505 may be performed according to examples as disclosed herein. In some examples, aspects of the operations of 1505 may be performed by Figure 8 The reference signal component 825 is used to perform the above.

[0197] At 1510, the method may include estimating a transmit signal associated with a data transmission, the transmit signal including a reference signal modified by a precoding matrix. The operations of 1510 may be performed according to examples as disclosed herein. In some examples, aspects of the operations of 1510 may be performed as described in reference to Figure 8 The transmitted signal estimation component 840 is used to perform the above operation.

[0198] At 1515, the method may include performing an iterative frequency domain imbalance estimation process to generate an estimate of the frequency domain imbalance based on the satisfaction of the estimation threshold. The operations of 1515 may be performed according to examples as disclosed herein. In some examples, aspects of the operations of 1515 may be performed as described in reference to Figure 8 The iterative estimation process component 845 is used to perform the above-described process.

[0199] At 1520, the method may include sending to the network entity an indication of an estimate of a frequency domain imbalance between an in-phase portion of a reference signal and a quadrature-phase portion of the reference signal based on a precoding matrix associated with the transmission from the network entity and an estimate of one or more channel conditions between the UE and the network entity. The operations of 1520 may be performed according to examples as disclosed herein. In some examples, aspects of the operations of 1520 may be performed by Figure 8 The imbalance estimation component 830 is used to perform the above operation.

[0200] At 1525, the method may include receiving a data transmission from a network entity based on transmitting an indication of an estimate of frequency domain imbalance. The operations of 1525 may be performed according to examples as disclosed herein. In some examples, aspects of the operations of 1525 may be performed as described in reference to Figure 8 The data sending and receiving component 835 is used to execute.

[0201] Fig.16 A flowchart illustrating a method 1600 for supporting frequency domain imbalance correction according to one or more examples disclosed herein is illustrated. The operations of the method 1600 may be implemented by a network entity or a component thereof as described herein. For example, the operations of the method 1600 may be implemented by a network entity or a component thereof as described herein. Figures 1 to 5 and Figures 10 to 13 In some examples, the network entity may execute an instruction set to control the functional elements of the network entity to perform the described functions. Additionally or alternatively, the network entity may use dedicated hardware to perform various aspects of the described functions.

[0202] At 1605, the method may include sending a reference signal to the UE. The operations of 1605 may be performed according to examples as disclosed herein. In some examples, aspects of the operations of 1605 may be performed by Fig.12 The reference signal component 1225 is used to perform the above.

[0203] At 1610, the method may include receiving an indication of a first estimate of a frequency domain imbalance between an in-phase portion of a transmission chain of a network entity and a quadrature-phase portion of a transmission chain of the network entity, the first estimate based on a reference signal, a precoding matrix associated with a transmission from the network entity, and an estimate of a channel between the UE and the network entity. The operations of 1610 may be performed according to examples as disclosed herein. In some examples, aspects of the operations of 1610 may be performed by Fig.12 The imbalance estimation component 1230 is used to perform the above operation.

[0204] At 1615, the method may include performing an imbalance compensation operation of an in-phase portion and a quadrature-phase portion of a balanced transmission chain associated with a transmission chain of a network entity based on the first estimate of frequency domain imbalance. The operations of 1615 may be performed according to examples as disclosed herein. In some examples, aspects of the operations of 1615 may be performed as described in reference to Fig.12 The imbalance compensation component 1235 is used to perform the above operation.

[0205] At 1620, the method may include sending data to the UE based on performing the imbalance compensation operation. The operations of 1620 may be performed according to examples as disclosed herein. In some examples, aspects of the operations of 1620 may be performed as described in reference Fig.12The data sending component 1240 is used to execute.

[0206] The following provides an overview of various aspects of the disclosure:

[0207] Aspect 1: A method for wireless communication at a UE, the method comprising: receiving a reference signal from a network entity; sending an indication of an estimate of a frequency domain imbalance between an in-phase portion of the reference signal and a quadrature-phase portion of the reference signal to the network entity based at least in part on a precoding matrix associated with the transmission from the network entity and an estimate of one or more channel conditions between the UE and the network entity; and receiving a data transmission from the network entity based at least in part on sending the indication of the estimate of the frequency domain imbalance.

[0208] Aspect 2: A method according to Aspect 1, wherein the reference signal is affected by the channel condition and the frequency domain imbalance, the method further comprising: estimating a transmit signal associated with the data transmission, the transmit signal comprising the reference signal modified by the pre-decoding matrix; and performing an iterative frequency domain imbalance estimation process for generating the estimate of the frequency domain imbalance based at least in part on satisfying an estimation threshold.

[0209] Aspect 3: A method according to Aspect 2, wherein the iterative frequency domain imbalance estimation process includes: estimating the channel condition; estimating the frequency domain imbalance based at least in part on the channel condition and the transmitted signal; applying compensation parameters to the reference signal; and determining whether the difference between the estimate of the frequency domain imbalance and the frequency domain imbalance satisfies the estimation threshold.

[0210] Aspect 4: The method according to any one of aspects 2 to 3, wherein the frequency domain imbalance is estimated by performing least square estimation or minimum mean square error estimation or any combination thereof.

[0211] Aspect 5: The method according to any one of aspects 1 to 4, further comprising receiving an indication of the precoding matrix from the network entity.

[0212] Aspect 6: According to the method described in any one of Aspects 1 to 5, the method further includes: receiving an indication from the network entity that the UE is to estimate the frequency domain imbalance based at least in part on a default precoding matrix, wherein the precoding matrix is ​​the default precoding matrix.

[0213] Aspect 7: According to the method according to any one of aspects 1 to 6, the method further comprises: receiving an indication of a timing for generating the estimate of the frequency domain imbalance, wherein the estimate of the frequency domain imbalance is sent according to the timing.

[0214] Aspect 8: A method for wireless communication at a network entity, the method comprising: sending a reference signal to a UE; receiving an indication of a first estimate of a frequency domain imbalance between an in-phase portion of a transmit chain of the network entity and a quadrature-phase portion of the transmit chain of the network entity, the first estimate being based at least in part on the reference signal, a precoding matrix associated with a transmission from the network entity, and an estimate of a channel between the UE and the network entity; performing an imbalance compensation operation associated with the transmit chain of the network entity to balance the in-phase portion and the quadrature-phase portion of the transmit chain based at least in part on the first estimate of the frequency domain imbalance; and sending data to the UE based at least in part on performing the imbalance compensation operation.

[0215] Aspect 9: The method according to aspect 8, wherein the imbalance compensation operation includes applying the first estimate of the frequency domain imbalance to a transmission signal associated with the data transmission.

[0216] Aspect 10: According to the method described in any one of Aspects 8 to 9, the method also includes: receiving corresponding additional estimates of the frequency domain imbalance from one or more other UEs, each corresponding additional estimate being at least partially based on the reference signal, the pre-decoding matrix, and an estimate of the channel condition between the network entity and a corresponding additional UE in the one or more other UEs, wherein the imbalance compensation operation is performed at least partially based on an average of the first estimate and the corresponding additional estimate.

[0217] Aspect 11: The method of aspect 10, wherein the first estimate and the corresponding additional estimates are averaged by assigning a weight to each of the first estimate and the corresponding additional estimates based at least in part on a quality metric.

[0218] Aspect 12: The method according to any one of aspects 8 to 11, further comprising sending an indication of the precoding matrix to the UE, wherein the precoding matrix is ​​applied in the transmission chain of the network entity.

[0219] Aspect 13: According to the method described in any one of Aspects 8 to 12, the method further includes: sending an indication to the UE that the UE is to estimate the frequency domain imbalance based at least in part on a default precoding matrix, wherein the precoding matrix is ​​the default precoding matrix.

[0220] Aspect 14: The method according to any one of aspects 8 to 13, wherein the imbalance compensation operation is performed after applying the pre-coding matrix and before modulating the in-phase part and the quadrature-phase part.

[0221] Aspect 15: According to the method of any one of Aspects 8 to 14, the method further comprises: sending an indication of a timing for generating the estimate of the frequency domain imbalance, wherein the indication of the first estimate of the frequency domain imbalance is received according to the timing.

[0222] Aspect 16: An apparatus for performing wireless communications at a UE, the apparatus comprising a processor; a memory coupled to the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to perform a method according to any one of Aspects 1 to 7.

[0223] Aspect 17: An apparatus for wireless communication at a UE, the apparatus comprising at least one component for performing the method according to any one of aspects 1 to 7.

[0224] Aspect 18: A non-transitory computer-readable medium storing a code for wireless communication at a UE, the code comprising instructions executable by a processor to perform the method according to any one of aspects 1 to 7.

[0225] Aspect 19: An apparatus for wireless communication at a network entity, the apparatus comprising a processor; a memory coupled to the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to perform a method according to any one of Aspects 8 to 15.

[0226] Aspect 20: An apparatus for wireless communication at a network entity, the apparatus comprising at least one component for performing the method according to any one of aspects 8 to 15.

[0227] Aspect 21: A non-transitory computer-readable medium storing code for wireless communication at a network entity, the code comprising instructions executable by a processor to perform the method according to any one of aspects 8 to 15.

[0228] It should be noted that the methods described herein describe possible implementations, and that the operations and steps may be rearranged or otherwise modified and other implementations are possible. In addition, aspects from two or more methods may be combined.

[0229] Although aspects of LTE, LTE-A, LTE-A Pro, or NR systems may be described for example purposes, and LTE, LTE-A, LTE-A Pro, or NR terminology may be used in much of the description, the techniques described herein may also be applicable to networks other than LTE, LTE-A, LTE-A Pro, or NR networks. For example, the techniques described may be applicable to various other wireless communication systems, such as Ultra Mobile Broadband (UMB), Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM, and other systems and radio technologies not explicitly mentioned herein.

[0230] The information and signals described herein may be represented using any of a variety of different techniques and methods. For example, data, instructions, commands, information, signals, bits, symbols, and chips mentioned throughout the specification may be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, optical fields or optical particles, or any combination thereof.

[0231] The various illustrative blocks and components described in conjunction with the disclosure herein may be implemented or executed using a general purpose processor, DSP, ASIC, CPU, FPGA or other programmable logic device, discrete gate or transistor logic components, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in an alternative, the processor may be any processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration).

[0232] The functions described herein may be implemented using hardware, software executed by a processor, firmware, or any combination thereof. If implemented using software executed by a processor, the functions may be stored as one or more instructions or codes of a computer-readable medium, or sent using one or more instructions or codes of a computer-readable medium. Other examples and specific implementations are within the scope of this disclosure and the appended claims. For example, due to the nature of software, the functions described herein may be implemented using software executed by a processor, hardware, firmware, hard wiring, or a combination of any of these items. Features that implement the functions may also be physically located at different locations, including being distributed so that the various parts of the functions are implemented at different physical locations.

[0233] Computer-readable media include both non-transient computer storage media and communication media, which include any media that facilitates the transfer of computer programs from one location to another. Non-transient storage media can be any available media that can be accessed by a general or special computer. By way of example and not limitation, non-transient computer-readable media may include RAM, ROM, electrically erasable programmable ROM (EEPROM), flash memory, compact disc (CD) ROM or other optical disc storage devices, magnetic disk storage devices or other magnetic storage devices, or may be used to carry or store desired program code components in the form of instructions or data structures and any other non-transient media that can be accessed by a general or special computer or a general or special processor. Moreover, any connection is appropriately referred to as a computer-readable medium. For example, if the software is sent from a website, server or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL) or wireless technologies such as infrared, radio and microwaves, coaxial cable, fiber optic cable, twisted pair, DSL or wireless technologies such as infrared, radio and microwaves are included in the definition of computer-readable media. As used herein, disks and optical disks include CDs, laser disks, optical disks, digital versatile disks (DVDs), floppy disks, and Blu-ray disks. Disks can reproduce data magnetically, and optical disks can reproduce data optically using lasers. Combinations of the above are also included within the scope of computer-readable media.

[0234] As used herein (including in the claims), "or" used in a list of items (e.g., a list of items followed by a phrase such as "at least one of" or "one or more of") indicates an inclusive list, such that, for example, a list of at least one of A, B, or C means A or B or C or AB or AC or BC or ABC (e.g., A and B and C). In addition, as used herein, the phrase "based on" should not be interpreted as a reference to a closed set of conditions. For example, an example step described as "based on condition A" can be based on both condition A and condition B without departing from the scope of the present disclosure. In other words, as used herein, the phrase "based on" should be interpreted in the same manner as the phrase "based at least in part on."

[0235] The term "determining" encompasses a variety of actions, and thus, "determining" may include calculating, computing, processing, deriving, investigating, looking up (such as via looking up in a table, database or other data structure), ascertaining, and the like. Furthermore, "determining" may include receiving (e.g., receiving information), accessing (e.g., accessing data stored in a memory), etc. Additionally, "determining" may include parsing, obtaining, selecting, choosing, establishing, and other such similar actions.

[0236] In the drawings, similar components or features may have the same reference label. In addition, various components of the same type may be distinguished by following the reference label with a dash and a second label to distinguish between similar components. If only the first reference label is used in the specification, the description may apply to any of the similar components having the same first reference label, regardless of the second or other subsequent reference labels.

[0237] The descriptions set forth herein in conjunction with the accompanying drawings describe example configurations and do not represent all examples that may be implemented or within the scope of the claims. The term "example" as used herein means "used as an example, instance, or illustration," rather than "preferred" or "advantageous over other examples." The specific implementation includes specific details to provide an understanding of the described techniques. However, these techniques may be practiced without these specific details. In some cases, known structures and devices are shown in block diagram form to avoid obscuring the concepts of the described examples.

[0238] The description herein is provided to enable one of ordinary skill in the art to implement or use the present disclosure. Various modifications to the present disclosure will be apparent to one of ordinary skill in the art, and the general principles defined herein may be applied to other variations without departing from the scope of the present disclosure. Thus, the present disclosure is not limited to the examples and designs described herein, but should be granted the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An apparatus for wireless communication at a user equipment (UE), the apparatus comprising: processor; and a memory coupled to the processor and storing instructions executable by the processor to cause the apparatus to: receiving a reference signal from a network entity; transmitting to the network entity an indication of an estimate of a frequency domain imbalance between an in-phase portion of the reference signal and a quadrature-phase portion of the reference signal based at least in part on a precoding matrix associated with the transmission from the network entity and an estimate of one or more channel conditions between the UE and the network entity; as well as A data transmission is received from the network entity based at least in part on sending the indication of the estimate of the frequency domain imbalance.

2. The apparatus of claim 1 , wherein the reference signal is affected by the one or more channel conditions and the frequency domain imbalance, and the instructions are further executable by the processor to cause the apparatus to: estimating a transmit signal associated with the data transmission, the transmit signal comprising the reference signal modified by the precoding matrix; and An iterative frequency domain imbalance estimation process is performed that generates the estimate of the frequency domain imbalance based at least in part on the satisfaction of an estimation threshold.

3. The apparatus of claim 2, wherein the instructions for performing the iterative frequency domain imbalance estimation process are executable by the processor to cause the apparatus to: estimating the one or more channel conditions; estimating the frequency domain imbalance based at least in part on the one or more channel conditions and the estimated transmit signal; applying compensation parameters to the reference signal; as well as It is determined whether a difference between the estimate of the frequency domain imbalance and the frequency domain imbalance satisfies the estimation threshold. 4 . The apparatus according to claim 2 , wherein the frequency domain imbalance is estimated by performing least square estimation or minimum mean square error estimation or any combination thereof.

5. The apparatus of claim 1, wherein the instructions are further executable by the processor to cause the apparatus to receive an indication of the precoding matrix from the network entity.

6. The apparatus of claim 1, wherein the instructions are further executable by the processor to cause the apparatus to: receiving, from the network entity, an indication that the UE is to estimate the frequency domain imbalance based at least in part on a default precoding matrix, The precoding matrix is ​​the default precoding matrix.

7. The apparatus of claim 1, wherein the instructions are further executable by the processor to cause the apparatus to: receiving an indication of a timing for generating said estimate of said frequency domain imbalance, Wherein the estimate of the frequency domain imbalance is sent according to the timing.

8. An apparatus for wireless communication at a network entity, the apparatus comprising: processor; and a memory coupled to the processor and storing instructions executable by the processor to cause the apparatus to: sending a reference signal to a user equipment (UE); receiving an indication of a first estimate of a frequency domain imbalance between an in-phase portion of a transmit chain of the network entity and a quadrature-phase portion of the transmit chain of the network entity, the first estimate based at least in part on the reference signal, a precoding matrix associated with transmissions from the network entity, and an estimate of a channel between the UE and the network entity; performing an imbalance compensation operation associated with the transmit chain of the network entity to balance the in-phase portion and the quadrature-phase portion of the transmit chain based at least in part on the first estimate of the frequency domain imbalance; and Data transmission is sent to the UE based at least in part on performing the imbalance compensation operation.

9. The apparatus of claim 8, wherein the imbalance compensation operation comprises applying the first estimate of the frequency domain imbalance to a transmit signal associated with the data transmission.

10. The apparatus of claim 8, wherein the instructions are further executable by the processor to cause the apparatus to: receiving respective additional estimates of the frequency domain imbalance from one or more other UEs, each respective additional estimate being based at least in part on the reference signal, the precoding matrix, and an estimate of a channel condition between the network entity and a respective additional UE of the one or more other UEs, Wherein the imbalance compensation operation is performed based at least in part on an average of the first estimate and the corresponding additional estimate.

11. The device of claim 10, wherein the first estimate and the respective additional estimates are averaged by assigning a weight to each of the first estimate and the respective additional estimates based at least in part on a quality metric.

12. The apparatus of claim 8, wherein the instructions are further executable by the processor to cause the apparatus to send an indication of the precoding matrix to the UE, wherein the precoding matrix is ​​applied in the transmit chain of the network entity.

13. The apparatus of claim 8, wherein the instructions are further executable by the processor to cause the apparatus to: sending an indication to the UE that the UE is to estimate the frequency domain imbalance based at least in part on a default precoding matrix, The precoding matrix is ​​the default precoding matrix.

14. The apparatus of claim 8, wherein the imbalance compensation operation is performed after applying the precoding matrix and before modulating the in-phase portion and the quadrature-phase portion.

15. The apparatus of claim 8, wherein the instructions are further executable by the processor to cause the apparatus to: sending an indication of a timing for generating said estimate of said frequency domain imbalance, Wherein the indication of the first estimate of the frequency domain imbalance is received according to the timing.

16. A method for wireless communication at a user equipment (UE), the method comprising: receiving a reference signal from a network entity; transmitting to the network entity an indication of an estimate of a frequency domain imbalance between an in-phase portion of the reference signal and a quadrature-phase portion of the reference signal based at least in part on a precoding matrix associated with the transmission from the network entity and an estimate of one or more channel conditions between the UE and the network entity; as well as A data transmission is received from the network entity based at least in part on sending the indication of the estimate of the frequency domain imbalance.

17. The method according to claim 16, wherein the reference signal is affected by the one or more channel conditions and the frequency domain imbalance, the method further comprising: estimating a transmit signal associated with the data transmission, the transmit signal comprising the reference signal modified by the precoding matrix; as well as An iterative frequency domain imbalance estimation process is performed that generates the estimate of the frequency domain imbalance based at least in part on the satisfaction of an estimation threshold.

18. The method of claim 17, wherein the iterative frequency domain imbalance estimation process comprises: estimating the one or more channel conditions; estimating the frequency domain imbalance based at least in part on the one or more channel conditions and the transmit signal; applying compensation parameters to the reference signal; as well as It is determined whether a difference between the estimate of the frequency domain imbalance and the frequency domain imbalance satisfies the estimation threshold.

19. The method of claim 17, wherein the frequency domain imbalance is estimated by performing least square estimation or minimum mean square error estimation or any combination thereof.

20. The method of claim 16, further comprising receiving an indication of the precoding matrix from the network entity.

21. The method according to claim 16, further comprising: receiving, from the network entity, an indication that the UE is to estimate the frequency domain imbalance based at least in part on a default precoding matrix, The precoding matrix is ​​the default precoding matrix.

22. The method according to claim 16, further comprising: receiving an indication of a timing for generating said estimate of said frequency domain imbalance, Wherein the estimate of the frequency domain imbalance is sent according to the timing.

23. A method for wireless communication at a network entity, the method comprising: sending a reference signal to a user equipment (UE); receiving an indication of a first estimate of a frequency domain imbalance between an in-phase portion of a transmit chain of the network entity and a quadrature-phase portion of the transmit chain of the network entity, the first estimate based at least in part on the reference signal, a precoding matrix associated with transmissions from the network entity, and an estimate of a channel between the UE and the network entity; performing an imbalance compensation operation associated with the transmit chain of the network entity to balance the in-phase portion and the quadrature-phase portion of the transmit chain based at least in part on the first estimate of the frequency domain imbalance; and Data transmission is sent to the UE based at least in part on performing the imbalance compensation operation.

24. The method of claim 23, wherein the imbalance compensation operation comprises applying the first estimate of the frequency domain imbalance to a transmit signal associated with the data transmission.

25. The method according to claim 23, further comprising: receiving respective additional estimates of the frequency domain imbalance from one or more other UEs, each respective additional estimate being based at least in part on the reference signal, the precoding matrix, and an estimate of a channel condition between the network entity and a respective additional UE of the one or more other UEs, Wherein the imbalance compensation operation is performed based at least in part on an average of the first estimate and the corresponding additional estimate.

26. The method of claim 25, wherein the first estimate and the respective additional estimates are averaged by assigning a weight to each of the first estimate and the respective additional estimates based at least in part on a quality metric.

27. The method of claim 23, further comprising sending an indication of the precoding matrix to the UE, wherein the precoding matrix is ​​applied in the transmit chain of the network entity.

28. The method according to claim 23, further comprising: sending an indication to the UE that the UE is to estimate the frequency domain imbalance based at least in part on a default precoding matrix, The precoding matrix is ​​the default precoding matrix.

29. The method of claim 23, wherein the imbalance compensation operation is performed after applying the precoding matrix and before modulating the in-phase portion and the quadrature-phase portion.

30. The method of claim 23, further comprising: sending an indication of a timing for generating said estimate of said frequency domain imbalance, Wherein the indication of the first estimate of the frequency domain imbalance is received according to the timing.

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