Joint gain and phase mismatch canceller and equalizer for downlink assisted by pre-decoder signaling

Abstract

Methods, systems, and devices for wireless communication are described. A user equipment (UE) may receive a downlink message that may include an indication of a pre-decoder applied to one or more downlink signals. The UE may receive the one or more downlink signals using a demodulation reference signal (DMRS) and the pre-decoder, wherein the one or more downlink signals may be mismatched in gain and phase. The UE may perform an iterative channel estimation process to estimate a downlink channel. The UE may then perform a gain and phase mismatch equalization process to equalize the estimated gain and phase mismatch of the one or more downlink signals based on the estimated downlink channel and the pre-decoder. The UE may then receive one or more equalized downlink signals according to the gain and phase mismatch equalization process.

Description

[0001] Cross-reference

[0002] This patent application claims priority to U.S. Patent Application No. 18 / 049,738, titled "JOINT GAIN AND PHASE MISMATCH CANCELLER AND EQUALIZER FOR DOWNLINK AIDED BY PRECODER SIGNALING", filed on October 26, 2022, by Regev et al., which is assigned to the assignee of the present application and is hereby incorporated by reference in its entirety. Field of the Invention

[0003] The following relates to wireless communication, including a joint gain and phase mismatch canceller and equalizer for a downlink aided by precoder signaling. Background Art

[0004] Wireless communication systems are widely deployed to provide various types of communication content, such as voice, video, packet data, messaging, broadcasting, and so on. These systems may be capable of supporting communication with multiple users by sharing available system resources (e.g., time, frequency, and power). Examples of such multi-access systems include fourth-generation (4G) systems (such as Long-Term Evolution (LTE) systems, LTE-Advanced (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 multi-access communication system may include one or more base stations, each of which supports wireless communication for communication devices, which may be referred to as User Equipment (UE). Summary of the Invention

[0005] The described techniques relate to improved methods, systems, devices, and apparatuses that support a joint gain and phase mismatch canceller and equalizer for a downlink assisted by precoder signaling. For example, a user equipment (UE) may support gain and phase mismatch estimation and cancellation processes to reduce network energy consumption and increase signaling throughput. The UE may receive an indication of a precoder associated with one or more downlink signals transmitted via a downlink channel from a network entity. The UE may use the indication of the precoder and one or more demodulation reference signals (DMRS) to estimate the downlink channel and receive and decode the one or more downlink signals, and in some cases, the one or more downlink signals may be mismatched in gain, phase, or both.

[0006] In some examples, the UE may estimate a physical channel associated with the one or more downlink signals and may perform a gain and phase mismatch estimation process to estimate the mismatch between the one or more downlink signals. The UE may perform an iterative channel estimation process based on the estimated gain and phase and may use the channel estimation as well as the gain and phase estimation to perform a gain and phase mismatch cancellation and equalization process. In some cases, the UE may perform the gain and phase cancellation and the channel equalization process simultaneously.

[0007] A method for wireless communication at a UE is described. The method may include: receiving, via a downlink channel, a downlink message including an indication of a precoder applied to one or more downlink signals; receiving the one or more downlink signals using at least one DMRS and the precoder, wherein the one or more downlink signals are at least partially mismatched in gain and phase; performing an iterative channel estimation process to estimate the downlink channel; performing a gain and phase mismatch equalization process at the UE to equalize the estimated gain and phase mismatch of the one or more downlink signals based on the estimated downlink channel and the precoder; and receiving one or more equalized downlink signals according to the gain and phase mismatch equalization process.

[0008] A device for wireless communication at a UE is described. The device 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 device to: receive, via a downlink channel, a downlink message including an indication of a pre - decoder applied to one or more downlink signals; receive the one or more downlink signals using at least one DMRS and the pre - decoder, wherein the one or more downlink signals are at least partially mismatched in gain and phase; perform an iterative channel estimation process to estimate the downlink channel; perform, at the UE, a gain and phase mismatch equalization process to equalize the estimated gain and phase mismatch of the one or more downlink signals based on the estimated downlink channel and the pre - decoder; and receive one or more equalized downlink signals according to the gain and phase mismatch equalization process.

[0009] Another device for wireless communication at a UE is described. The device may include: means for receiving, via a downlink channel, a downlink message including an indication of a pre - decoder applied to one or more downlink signals; means for receiving the one or more downlink signals using at least one DMRS and the pre - decoder, wherein the one or more downlink signals are at least partially mismatched in gain and phase; means for performing an iterative channel estimation process to estimate the downlink channel; means for performing, at the UE, a gain and phase mismatch equalization process to equalize the estimated gain and phase mismatch of the one or more downlink signals based on the estimated downlink channel and the pre - decoder; and means for receiving one or more equalized downlink signals according to the gain and phase mismatch equalization process.

[0010] A non - transitory computer - readable medium storing code for wireless communication at a UE is described. The code may include instructions executable by a processor to: receive, via a downlink channel, a downlink message including an indication of a pre - decoder applied to one or more downlink signals; receive the one or more downlink signals using at least one DMRS and the pre - decoder, wherein the one or more downlink signals are at least partially mismatched in gain and phase; perform an iterative channel estimation process to estimate the downlink channel; perform, at the UE, a gain and phase mismatch equalization process to equalize the estimated gain and phase mismatch of the one or more downlink signals based on the estimated downlink channel and the pre - decoder; and receive one or more equalized downlink signals according to the gain and phase mismatch equalization process.

[0011] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, components, or instructions for: performing an iterative channel estimation process to estimate a physical channel associated with the one or more downlink signals using at least one DMRS, and estimating an estimated gain and phase mismatch based on the estimated physical channel, a pre-coder, or both.

[0012] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, receiving the one or more downlink signals may include operations, features, components, or instructions for: applying one or more pre-coder coefficients to the one or more downlink signals.

[0013] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, performing the iterative channel estimation process may include operations, features, components, or instructions for: performing a first channel estimation process, performing a gain and phase mismatch equalization process, and performing at least a second channel estimation process based on the estimated gain and phase mismatch.

[0014] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, performing the gain and phase mismatch equalization process may include operations, features, components, or instructions for: eliminating at least a portion of the estimated gain and phase mismatch.

[0015] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, receiving a downlink message including an indication of a pre-coder may include operations, features, components, or instructions for: receiving an indication of the pre-coder via a set of downlink pre-coded data, wherein one or more pre-coder coefficients may be determined based on the set of downlink pre-coded data.

[0016] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, components, or instructions for: performing a gain and phase mismatch equalization process and simultaneously equalizing the estimated gain and phase mismatch of the one or more downlink signals.

[0017] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, receiving the one or more downlink signals may include operations, features, components, or instructions for: reproducing the one or more downlink signals based on the at least one DMRS and the pre-coder for the gain and phase mismatch equalization process.

[0018] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, receiving the indication of the pre-decoder may include operations, features, components, or instructions for: receiving an indication of a duration, a time slot number, or both, for which the pre-decoder can be applied to one or more downlink signals.

[0019] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, the value of the pre-decoder includes a static value or a pseudo-random value, and the methods, apparatuses, and non-transitory computer-readable media may include operations, features, components, or instructions for: performing the gain and phase mismatch equalization process based on the value of the pre-decoder.

[0020] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, the indication of the pre-decoder includes a first indication of a first pre-decoder, and the methods, apparatuses, and non-transitory computer-readable media may include operations, features, components, or instructions for: receiving, via the first indication of the first pre-decoder, a second indication of a second pre-decoder to be applied to the one or more downlink signals after a threshold duration, and performing a gain and phase mismatch equalization process according to the second pre-decoder.

[0021] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may further include operations, features, components, or instructions for: receiving a periodic indication from a network entity, the periodic indication indicating the periodicity for which a UE may perform a gain and phase mismatch equalization process based on one or more operating factors of the network entity.

[0022] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, the gain and phase mismatch equalization process includes an in-phase quadrature phase (IQ) mismatch equalization process.

[0023] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, the estimated gain and phase mismatch may be a frequency-dependent gain and phase mismatch. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 and Figure 2 Illustrates examples of wireless communication systems supporting a joint gain and phase mismatch canceller and equalizer for downlink assisted by pre-decoder signaling in accordance with one or more aspects of the present disclosure.

[0025] Figure 3 Illustrates examples of multiple-input multiple-output (MIMO) systems supporting a joint gain and phase mismatch canceller and equalizer for downlink assisted by pre-decoder signaling in accordance with one or more aspects of the present disclosure.

[0026] Figure 4 Illustrates an example of a flowchart supporting a joint gain and phase mismatch canceller and equalizer for a downlink assisted by precoder signaling in accordance with one or more aspects of the present disclosure.

[0027] Figure 5 Illustrates an example of a process flow supporting a joint gain and phase mismatch canceller and equalizer for a downlink assisted by precoder signaling in accordance with one or more aspects of the present disclosure.

[0028] Figure 6 and Figure 7 Illustrates a block diagram of a device supporting a joint gain and phase mismatch canceller and equalizer for a downlink assisted by precoder signaling in accordance with one or more aspects of the present disclosure.

[0029] Figure 8 Illustrates a block diagram of a communication manager supporting a joint gain and phase mismatch canceller and equalizer for a downlink assisted by precoder signaling in accordance with one or more aspects of the present disclosure.

[0030] Figure 9 Illustrates a schematic diagram of a system including a device supporting a joint gain and phase mismatch canceller and equalizer for a downlink assisted by precoder signaling in accordance with one or more aspects of the present disclosure.

[0031] Figures 10 to 12 Illustrates a flowchart showing a method supporting a joint gain and phase mismatch canceller and equalizer for a downlink assisted by precoder signaling in accordance with one or more aspects of the present disclosure. Detailed Description

[0032] Some wireless communication systems may use in-phase and quadrature-phase (IQ) modulators to generate radio frequency (RF) signals. For example, an IQ modulator may combine an in-phase signal with a quadrature signal to generate an RF signal. In such examples, the quadrature signal may be a phase-shifted copy of the in-phase signal (e.g., the quadrature signal may be phase-shifted 90 degrees relative to the in-phase signal). Before combining and transmitting the in-phase and quadrature signals, the IQ modulator may modify the amplitude of the in-phase signal, the quadrature signal, or both to generate different RF signals (e.g., modulated signals with different amplitudes and phases). In such cases, the IQ modulator may select different amplitudes and phases to increase transmit diversity in the wireless communication system.

[0033] However, in some cases, an IQ modulator may have inherent impairments due to the hardware components used (e.g., different hardware processing chains for each IQ signal component) or other factors. As a result, the IQ modulator may generate IQ signals with non-ideal characteristics. For example, the IQ modulator may generate IQ signals with gain errors and phase errors relative to the expected gain or phase. The gain and phase errors between the IQ signals may be referred to as gain and phase mismatches, IQ impairments, frequency-dependent IQ imbalances, IQ mismatches, or frequency-dependent residual sidebands (FDRSB). Due to the gain and phase mismatches, a wireless communication system may perform various gain and phase cancellation processes to eliminate or otherwise compensate for the gain and phase mismatches. In addition, the wireless communication system may operate in a high-frequency band (e.g., sub-THz band), which may utilize a network entity that includes a relatively large number of antennas, and each antenna may be associated with a different IQ modulator (e.g., IQ processing chain). In such cases, each IQ modulator may introduce different gain and phase mismatches, which may increase the complexity for the network entity to perform gain and phase mismatch cancellation for each IQ modulator associated with each antenna. That is, performing the gain and phase mismatch cancellation process for each IQ modulator may increase power consumption and computational complexity, and also increase the hardware cost from a network perspective.

[0034] To support efficient and relatively low-power gain and phase mismatch cancellation, and to avoid relatively high power consumption and computational complexity at the network entity, the gain and phase mismatch cancellation technique may be performed by the UE. For example, the UE may perform a processing procedure to perform gain and phase mismatch cancellation, with a relatively low impact on performance and power, and without additional hardware cost. In some specific implementations, the gain and phase mismatch may occur between a pre-coder (P) and a channel (H), and the IQ modulator may modulate the signal after the signal is processed by the pre-coder (but before the signal is transmitted through the channel). Since the impairments may occur between the pre-coder and the channel, the UE may be able to estimate the gain and phase mismatch if the information about the pre-coder and the channel is separately available to the UE.

[0035] In such examples, the network entity may send the indication of the pre-coder and the indication of the channel separately (e.g., rather than as a combined product) to the UE, and the UE may use the indication of the pre-coder and the demodulation reference signal (DMRS) to reproduce the transmitted signal from the network entity. Then, the UE may perform a channel estimation process (e.g., using one or more channel estimation methods or iterative channel estimation) to estimate the channel. The UE may use the estimated channel and the reproduced transmitted signal to estimate the IQ gain and phase mismatch. The UE may use the gain and phase mismatch estimation to simultaneously perform the gain and phase mismatch cancellation process and the existing channel equalization process to reduce the potential impact on the power overhead and performance at the UE.

[0036] Aspects of the present disclosure are first described in the context of a wireless communication system. Aspects of the present disclosure are further illustrated by and described with reference to multi-input multi-output (MIMO) systems, process flows, device diagrams, system diagrams, and flowcharts that relate to a joint gain and phase mismatch canceller and equalizer for a downlink assisted by precoder signaling.

[0037] Figure 1 An example of a wireless communication system 100 that supports a joint gain and phase mismatch canceller and equalizer for a downlink assisted by precoder signaling in accordance with one or more aspects of the present disclosure 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 LTE-Advanced (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.

[0038] 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 having 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 designations. In some examples, the network entities 105 and the UEs 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) within which the UEs 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 within which the network entity 105 and the UEs 115 may support signal communication according to one or more radio access technologies (RATs).

[0039] 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 both stationary and mobile at different times. The UEs 115 may be devices in different forms or having different capabilities. Figure 1 The UE 115 is illustrated. The UE 115 described herein may be capable of communicating with various types of devices, such as Figure 1 other UEs 115 or network entities 105 as shown.

[0040] 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, a device, an equipment, 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 yet 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 from these examples. Similarly, references to UE 115, network entity 105, device, equipment, computing system, etc. may include the disclosure of UE 115, network entity 105, device, equipment, computing system, etc. as nodes. For example, the disclosure that UE 115 is configured to receive information from network entity 105 also discloses that a first node is configured to receive information from a second node.

[0041] In some examples, network entity 105 may communicate with core network 130 or with each other or both. For example, network entity 105 may communicate with 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, network entity 105 may communicate with each other directly (e.g., directly between network entities 105) or indirectly (e.g., via core network 130) via backhaul communication links 120 (e.g., according to X2, Xn, or other interface protocols). In some examples, network entity 105 may communicate with each other via midhaul communication link 162 (e.g., according to midhaul interface protocol) or fronthaul communication link 168 (e.g., according to fronthaul interface protocol) or any combination thereof. Backhaul communication link 120, midhaul communication link 162, or fronthaul communication link 168 may be or include one or more wired links (e.g., electrical link, optical fiber link), one or more wireless links (e.g., radio link, wireless optical link), etc. or various combinations thereof. UE 115 may communicate with core network 130 via communication link 155.

[0042] One or more of the network entities 105 described herein may include or may be referred to as a base station 140 (e.g., transceiver base station, radio base station, NR base station, access point, radio transceiver, Node B, evolved Node B (eNB), next-generation Node B or giga Node B (any of which may be referred to as gNB), 5G NB, next-generation eNB (ng-eNB), home Node B, home evolved Node B or other suitable terms). In some examples, the network entity 105 (e.g., base station 140) may be implemented in an integrated (e.g., monolithic, stand-alone) base station architecture that may be configured to utilize a protocol stack physically or logically integrated within a single network entity 105 (e.g., a single RAN node such as base station 140).

[0043] In some examples, the network entity 105 may be implemented in a disaggregated architecture (e.g., disaggregated base station architecture, disaggregated RAN architecture) that may be configured to utilize a protocol stack physically or logically distributed between two or more network entities 105 such as an integrated access backhaul (IAB) network, open RAN (O-RAN) (e.g., a network configuration sponsored by the O-RAN Alliance) or virtualized RAN (vRAN) (e.g., cloud RAN (C-RAN)). For example, the network entity 105 may 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., near-real-time RIC (near-RT RIC), 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, intelligent radio head, remote radio head (RRH), remote radio unit (RRU) or transmit receive point (TRP). One or more components of the network entity 105 in a disaggregated 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 a disaggregated RAN architecture may be implemented as virtual units (e.g., virtual CU (VCU), virtual DU (VDU), virtual RU (VRU)).

[0044] The functional split between the CU 160, DU 165, and RU 170 is flexible and can support different functions, depending on which functions are performed at the CU 160, DU 165, or RU 170 (e.g., network layer functions, protocol layer functions, baseband functions, RF functions, and any combination thereof). For example, a functional split of the protocol stack can be employed between the CU 160 and the DU 165 such that the CU 160 can support one or more layers of the protocol stack and the DU 165 can support one or more different layers of the protocol stack. In some examples, the CU 160 can host higher protocol layer (e.g., layer 3 (L3), layer 2 (L2)) functions and signaling (e.g., radio resource control (RRC), service data adaptation protocol (SDAP), packet data convergence protocol (PDCP)). The CU 160 can be connected to one or more DU 165s or RU 170s, and one or more DU 165s or RU 170s can host lower protocol layers, such as layer 1 (L1) (e.g., physical (PHY) layer) or L2 (e.g., radio link control (RLC) layer, media access control (MAC) layer) functions and signaling, and can each be at least partially controlled by the CU 160. Additionally or alternatively, a functional split of the protocol stack can be employed between the DU 165 and the RU 170 such that the DU 165 can support one or more layers of the protocol stack and the RU 170 can support one or more different layers of the protocol stack. The DU 165 can support one or more different cells (e.g., via one or more RU 170s). In some cases, the functional split between the CU 160 and the DU 165 or between the DU 165 and the RU 170 can be within a protocol layer (e.g., some functions of a protocol layer can be performed by one of the CU 160, DU 165, or RU 170, while other functions of that protocol layer are performed by a different one of the CU 160, DU 165, or RU 170). The CU 160 can be further functionally split into a CU control plane (CU-CP) and a CU user plane (CU-UP) function. The CU 160 can be connected to one or more DU 165s via an intermediate transport communication link 162 (e.g., F1, F1-c, F1-u), and the DU 165 can be connected to one or more RU 170s via a fronthaul communication link 168 (e.g., open fronthaul (FH) interface). In some examples, the intermediate transport communication link 162 or the fronthaul communication link 168 can be implemented according to the interfaces (e.g., channels) between the layers of the protocol stack, which are supported by the respective network entities 105 communicating via such communication links.

[0045] In some wireless communication systems (e.g., wireless communication system 100), the 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 node 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 donor network entity 105 (e.g., donor base station 140). One or more donor network entities 105 (e.g., IAB donors) may communicate with one or more additional network entities 105 (e.g., IAB nodes 104) via the supported access and backhaul links (e.g., backhaul communication link 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 donor. The IAB-MT may include a separate antenna set for relaying communications with the UE 115, or may share the same antenna (e.g., of the RU 170) of the IAB node 104 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 nodes 104, UEs 115) within a relay chain or configuration (e.g., downstream) of the access network. In such cases, one or more components of the split 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.

[0046] For example, the access network (AN) or RAN may include communication between access nodes (e.g., IAB donors), IAB nodes 104, and one or more UEs 115. The IAB donor may facilitate the 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 donor may include a CU 160 and at least one DU 165 (e.g., and an RU 170), where the CU 160 may communicate with the core network 130 via an interface (e.g., a backhaul link). The IAB donor and the IAB node 104 may communicate via an F1 interface according to a protocol that defines signaling messages (e.g., the F1 AP protocol). Additionally or alternatively, the CU 160 may communicate with the core network via an interface (which may be an example of a part of the backhaul link) and may communicate with other CUs 160 (e.g., CUs 160 associated with alternative IAB donors) via an Xn-C interface (which may be an example of a part of the backhaul link).

[0047] The IAB node 104 may refer to a RAN node that provides IAB functionality (e.g., access for UEs 115, wireless self-backhaul capabilities, etc.). The DU 165 may act as a distributed scheduling node towards the child nodes associated with the IAB node 104, and the IAB-MT may act as a scheduled node towards the parent node associated with the IAB node 104. That is, the IAB donor may be referred to as a parent node that communicates with one or more child nodes (e.g., the IAB donor 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, the IAB node 104 may also be referred to as a parent node or a 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 the DU interface (e.g., 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.

[0048] For example, the IAB node 104 may be referred to as a parent node supporting communication for a child IAB node or as a child node associated with an IAB donor or both. The IAB donor may include a CU 160 having a wired or wireless connection to the core network 130 (e.g., a fronthaul communication link 120), and may act as the parent node of the IAB node 104. For example, the DU 165 of the IAB donor may relay transmissions to the UE 115 via the IAB node 104, or may signal transmissions directly to the UE 115, or both. The CU 160 of the IAB donor may signal communication link establishment to the IAB node 104 via the F1 interface, and the IAB node 104 may schedule transmissions (e.g., transmissions relayed from the IAB donor to the UE 115) via the DU 165. That is, data may be relayed to and from the IAB node 104 via signaling over the NR Uu interface to the MT of the IAB node 104. Communication with the IAB node 104 may be scheduled by the DU 165 of the IAB donor, and communication with the IAB node 104 may be scheduled by the DU 165 of the IAB node 104.

[0049] In cases where the techniques described herein are applied in the context of a split RAN architecture, one or more components of the split RAN architecture may be configured to support a joint gain and phase mismatch canceller and equalizer for downlink assisted by precoder signaling as described herein. For example, some operations described as being performed by the UE 115 or the network entity 105 (e.g., the base station 140) may additionally or alternatively be performed by one or more components of the split RAN architecture (e.g., the IAB node 104, the DU 165, the CU 160, the RU 170, the RIC 175, the SMO 180).

[0050] The 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 "device" may also be referred to as a unit, a station, a terminal, or a client, etc. The 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, the 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.

[0051] The UE 115 described herein may be 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, or relay base stations, etc., as Figure 1 shown.

[0052] 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 set of RF spectrum resources having a physical layer structure defined to support one or more communication links 125. For example, a carrier for one or more communication links 125 may include a portion (e.g., a bandwidth part (BWP)) of an RF spectrum band operating 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 operation, user data, or other signaling. The wireless communication system 100 may support communication with the UE 115 using carrier aggregation or multi-carrier operation. According to a carrier aggregation configuration, the UE 115 may be configured to have 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 these devices and any part (e.g., entity, sub-entity) of the network entity 105. For example, the terms "transmit", "receive", or "communicate" when referring to the network entity 105 may refer to any part of the network entity 105 of the RAN (e.g., base station 140, CU 160, DU 165, RU 170) communicating with another device (e.g., directly or via one or more other network entities 105).

[0053] In some examples, such as in a carrier aggregation configuration, a carrier may also have acquisition signaling or control signaling for coordinating 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 the UE 115. A carrier may operate in stand-alone mode, in which case initial acquisition and connection may be performed by the UE 115 via the carrier, or a carrier may operate in non-stand-alone mode, in which case the connection is anchored using a different carrier (e.g., different carriers of the same or different radio access technologies).

[0054] The communication link 125 shown in the wireless communication system 100 may include other transmission configurations such as a downlink transmission (e.g., forward link transmission) from the network entity 105 to the UE 115, an uplink transmission (e.g., reverse link transmission) from the UE 115 to the network entity 105, or both. A carrier may carry downlink communication or uplink communication (e.g., in FDD mode), or may be configured to carry both downlink communication and uplink communication (e.g., in TDD mode).

[0055] 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 the "system bandwidth" of the carrier or the wireless communication system 100. For example, the carrier bandwidth may be one of a set of bandwidths for carriers of 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 capable of being configured to support communication using one of a 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., subband, BWP) or all of the carrier bandwidth.

[0056] The signal waveform transmitted via a carrier may include multiple subcarriers (e.g., using a multi-carrier modulation (MCM) technique such as orthogonal frequency division multiplexing (OFDM) or discrete Fourier transform spread OFDM (DFT-S-OFDM)). In a system employing an MCM technique, a resource element may refer to the 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 decoding rate of the modulation scheme, or both), such that a relatively high number of resource elements (e.g., during the transmission duration) and a relatively high-order modulation scheme may correspond to a relatively high rate of communication. Wireless communication resources may refer to a combination of RF spectrum resources, time resources, and spatial resources (e.g., spatial layers or beams), and the use of multiple spatial resources may increase the data rate or data integrity for communication with the UE 115.

[0057] One or more parameter sets for a carrier may be supported, and the parameter sets may include subcarrier spacing (Δf) and cyclic prefix. The carrier may be divided into one or more BWPs with the same or different parameter sets. In some examples, 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 the communication of UE 115 may be restricted to one or more active BWPs.

[0058] A time interval for network entity 105 or UE 115 may be expressed as a multiple of a basic time unit, which may refer to, for example, the sampling period T s = 1 / (Δf max ·N f ) seconds, where Δf max may represent the supported subcarrier spacing, and N f may represent the supported discrete Fourier transform (DFT) size. The time intervals of communication resources may be organized according to radio frames each having a specified 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).

[0059] Each frame may include a plurality of 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 (e.g., in the time domain) into subframes, 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 a certain number of symbol periods (e.g., depending on the length of the cyclic prefix appended to each symbol period). In some wireless communication systems 100, a time slot may be further divided into a plurality of mini-slots associated with one or more symbols. Excluding the cyclic prefix, each symbol period may be associated with one or more (e.g., N f ones) sampling periods. The duration of a symbol period may depend on the subcarrier spacing or the operating frequency band.

[0060] A subframe, time slot, mini-slot or symbol may be the smallest scheduling unit (e.g., in the time domain) of 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 wireless communication system 100 may be dynamically selected (e.g., in a burst of shortened TTIs (sTTIs)).

[0061] According to various techniques, carriers can be used to multiplex physical channels for communication. For example, one or more of time-division multiplexing (TDM) techniques, frequency-division multiplexing (FDM) techniques, or hybrid TDM-FDM techniques can be used to multiplex physical control channels and physical data channels for signaling via a downlink carrier. The control region of a physical control channel (e.g., a control resource set (CORESET)) can be defined by a set of symbol periods and can extend across the system bandwidth of a carrier or a subset of that system bandwidth. One or more control regions (e.g., CORESETs) can be configured for a set of UEs 115. For example, one or more of the UEs 115 can monitor or search a control region for control information according to one or more search space sets, and each search space set can include one or more control channel candidates in one or more aggregation levels arranged in a cascaded manner. The aggregation level of a control channel candidate can refer to the amount of control channel resources (e.g., control channel elements (CCEs)) associated with the coded information for a control information format with a given payload size. The set of search spaces can include a common search space set configured to transmit control information to the UEs 115 and a UE-specific search space set for transmitting control information to the UEs 115.

[0062] In some examples, the network entity 105 (e.g., the base station 140, the RU 170) can be movable and thus provide communication coverage for a moving coverage area 110. In some examples, different coverage areas 110 associated with different techniques can overlap, but the different coverage areas 110 can be supported by the same network entity 105. In some other examples, overlapping coverage areas 110 associated with different techniques can be supported by different network entities 105. The wireless communication system 100 can include, for example, a heterogeneous network in which different types of network entities 105 use the same or different radio access technologies to provide coverage for various coverage areas 110.

[0063] The wireless communication system 100 can be configured to support ultra-reliable communication or low-latency communication or various combinations thereof. For example, the wireless communication system 100 can be configured to support ultra-reliable low-latency communication (URLLC). The UE 115 can be designed to support ultra-reliable or low-latency or critical functions. Ultra-reliable communication can include private communication or group communication and can be supported by one or more services (such as push-to-talk, video, or data). Support for ultra-reliable, low-latency functions can include prioritizing services, and such services can be used for public safety or general commercial applications. The terms ultra-reliable, low-latency, and ultra-reliable low-latency can be used interchangeably herein.

[0064] In some examples, the UE 115 may be configured to support communicating 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 performing D2D communication in a group may be within the coverage area 110 of a network entity 105 (e.g., base station 140, RU 170), and the network entity 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 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, where each UE 115 transmits to each of the other UEs 115 in the group. In some examples, the network entity 105 may facilitate the scheduling of resources for D2D communication. In some other examples, D2D communication may be performed between UEs 115 without involving the network entity 105.

[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), which may include at least one control plane entity for managing access and mobility (e.g., a mobility management entity (MME), an access and mobility management function (AMF)) and at least one user plane entity for routing packets or interconnecting to external networks (e.g., a serving gateway (S-GW), a packet data network (PDN) gateway (P-GW), or a user plane function (UPF)). The control plane entity may manage non-access stratum (NAS) functions, such as the mobility, authentication, and bearer management of UEs 115 served by a network entity 105 (e.g., base station 140) associated with the core network 130. User IP packets may be passed 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. The IP services 150 may include access to the Internet, an intranet, an IP multimedia subsystem (IMS), or a packet-switched streaming service.

[0066] The wireless communication system 100 may operate using one or more frequency bands that can 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 the decimeter band because, in terms of length, the wavelength range is from approximately one decimeter to one meter. UHF waves may be blocked or redirected by buildings and environmental features (which may be referred to as clutter), but these waves may be sufficient to penetrate structures so that a macro cell can serve a UE 115 located indoors. Compared with communications using smaller frequencies and longer waves in the high frequency (HF) or very high frequency (VHF) portions of the spectrum below 300 MHz, communications using UHF waves may be associated with smaller antennas and shorter ranges (e.g., less than 100 kilometers).

[0067] The wireless communication system 100 may also operate using the super-high frequency (SHF) region (also referred to as the centimeter band) in the range of 3 GHz to 30 GHz or using the extremely high frequency (EHF) region of the spectrum (e.g., 30 GHz to 300 GHz) (also referred to as the millimeter band). In some examples, the wireless communication system 100 may support millimeter wave (mmW) communications between the UE 115 and network entities 105 (e.g., base station 140, RU 170), and the EHF antennas of the corresponding devices may be smaller and closer spaced than UHF antennas. In some examples, such techniques may facilitate the use of antenna arrays within the devices. However, the propagation of EHF transmissions may be affected by greater attenuation and shorter ranges 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 designated across these frequency regions may vary by country or regulatory body.

[0068] The wireless communication system 100 may utilize licensed and unlicensed RF spectrum bands. For example, the wireless communication system 100 may use an unlicensed band (such as the 5 GHz industrial, scientific, and medical (ISM) band) to employ licensed-assisted access (LAA), LTE unlicensed (LTE-U) radio access technology, or NR technology. When operating using an unlicensed RF spectrum band, devices such as network entities 105 and UE 115 may employ carrier sensing for collision detection and avoidance. In some examples, operation using an unlicensed band may be based on a carrier aggregation configuration (e.g., LAA) in combination with operation using a licensed band. Operation using unlicensed spectrum may include downlink transmissions, uplink transmissions, peer-to-peer (P2P) transmissions, device-to-device (D2D) transmissions, and so on.

[0069] The network entity 105 (e.g., base station 140, RU 170) or UE 115 may be equipped with multiple antennas, which may be used to employ techniques 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 within one or more antenna arrays or antenna panels, which may support MIMO operation or transmit or receive beamforming. For example, one or more base station antennas or antenna arrays may be co-located at an antenna integration location, such as at an antenna tower. In some examples, the 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 in multiple rows and columns that the network entity 105 may use for beamforming to support communication with the UE 115. Similarly, the UE 115 may include one or more antenna arrays, which may support various MIMO or beamforming operations. Additionally or alternatively, the antenna panel may support RF beamforming for signals transmitted via the antenna ports.

[0070] The network entity 105 or UE 115 may use MIMO communication to exploit multipath signal propagation and improve spectral efficiency by transmitting or receiving multiple signals via different spatial layers. Such techniques may be referred to as spatial multiplexing. The multiple signals may be transmitted, 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 techniques include: single-user MIMO (SU-MIMO), for which multiple spatial layers are transmitted to the same receiving device; and multi-user MIMO (MU-MIMO), for which multiple spatial layers are transmitted 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 can be used at a transmitting device or a receiving device (e.g., network entity 105, UE 115) to shape or direct an antenna beam (e.g., a transmit beam, a receive beam) along a spatial path between the transmitting device and the receiving device. Beamforming can be achieved by combining signals communicated via the antenna elements of an antenna array such that some signals propagating along a particular direction relative to the antenna array experience constructive interference while other signals experience destructive interference. Adjusting the signals communicated via the antenna elements can include the transmitting device or the receiving device applying an amplitude offset, a phase offset, or both to the signals carried via the antenna elements associated with the device. The adjustment associated with each of these antenna elements can be defined by a set of beamforming weights associated with a particular direction (e.g., relative to the antenna array of the transmitting device or the receiving device or relative to some other direction).

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

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

[0074] In some examples, transmissions performed by a device (e.g., by network entity 105 or UE 115) may be carried out 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 the system bandwidth or one or more sub-bands. Network entity 105 may transmit reference signals (e.g., cell-specific reference signal (CRS), 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., multi-panel type codebook, linear combination type codebook, port selection type codebook). Although these techniques are described with reference to signals transmitted by network entity 105 (e.g., base station 140, RU 170) in one or more directions, UE 115 may use similar techniques for transmitting signals multiple times in different directions (e.g., for identifying beam directions used by UE 115 for subsequent transmission or reception), or for transmitting signals in a single direction (e.g., for transmitting 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 receiving according to multiple receiving directions by: receiving via different antenna sub-arrays, processing the received signals according to different antenna sub-arrays, receiving according to different sets of receiving beamforming weights (e.g., different directional listening weight sets) applied to signals received at multiple antenna elements of an antenna array, or processing the received signals according to different sets of receiving beamforming weights 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). The single receiving configuration may be aligned along a beam direction determined based on listening according to different receiving 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] In some cases, the wireless communication system 100 may include devices that utilize IQ modulators to process communication signals. However, IQ modulators may have inherent impairments and introduce errors such as gain and phase mismatches into the wireless communication system 100. Due to the inherent gain and phase mismatches, the wireless communication system 100 may need to perform gain and phase cancellation processes to eliminate or otherwise compensate for the gain and phase mismatches. Additionally, performing the gain and phase cancellation processes at the network entity 105 may increase power consumption, computational complexity, and hardware costs (e.g., due to a large number of antennas each having a respective processing chain).

[0077] In accordance with aspects of the present disclosure, the gain and phase mismatch cancellation process may be performed at the UE 115, which may help reduce power consumption and complexity at the network entity 105. In some cases, the network entity 105 may send an indication of a precoder and an indication of a channel to the UE 115 separately (e.g., rather than as a combined product). The UE 115 may use the indication of the precoder and the DMRS to reproduce the transmitted signal from the network entity. The UE 115 may then perform a channel estimation process (e.g., using any channel estimation method) to estimate the channel. The UE 115 may use the estimated channel and the reproduced transmitted signal to estimate the IQ gain and phase mismatches. The UE 115 may use the gain and phase mismatch estimates to simultaneously perform the gain and phase mismatch cancellation process and an existing channel equalization process to reduce the potential impact on power overhead and performance at the UE 115.

[0078] Figure 2 An example of a wireless communication system 200 that supports a joint gain and phase mismatch canceller and equalizer for downlink assisted by precoder signaling in accordance with one or more aspects of the present disclosure is illustrated. In some cases, the wireless communication system 200 may implement aspects of the wireless communication system 100, or may be implemented by aspects of the wireless communication system 100. For example, the wireless communication system 200 may include a network entity 105-a, a UE 115-a, and a communication link 205, which may be examples of the network entity 105, the UE 115, and the communication link 125 as described in reference Figure 1 to the network entity 105, the UE 115, and the communication link 125.

[0079] Network entity 105-a may communicate with UE 115-a using communication link 205 within coverage area 110-a. Network entity 105-a and UE 115-a may establish communication link 205 via a communication channel (e.g., air interface, frequency band, or bandwidth part). In some cases, to improve communication quality, network entity 105-a may perform various signal processing techniques on one or more communication signals 210 before transmission. For example, network entity 105-a may process one or more communication signals 210 by performing signal pre-coding (e.g., applying a pre-coder to a downlink signal) and performing IQ modulation to transmit a downlink signal in a MIMO system. In such examples, network entity 105-a may use a pre-coder to increase throughput at UE 115-a and support MIMO communication in which multiple data streams are transmitted from network entity 105-a. In some examples, network entity 105-a may use one or more IQ modulators to generate one or more RF signals (e.g., with various combinations of gain and phase). In such examples, network entity 105-a may perform IQ modulation on one or more communication signals 210 after applying the pre-coder and before transmitting the signal over the communication channel via communication link 205.

[0080] However, in some examples, each IQ modulator may be associated with signaling mismatches or errors introduced by hardware components, different hardware processing chains, and other factors. For example, an IQ modulator may generate an RF signal with gain (e.g., amplitude) and phase errors or other non-ideal characteristics. Such errors may be referred to herein as gain and phase mismatches, IQ mismatches, IQ impairments, frequency-dependent IQ imbalances, FDRSB, etc. In some cases, if the IQ mismatch is not corrected, wireless communication system 200 may experience degraded operating performance (e.g., limited link performance, lower transmission quality). Therefore, to improve operating performance, throughput, and overall communication quality, wireless communication system 200 may compensate (e.g., eliminate, equalize, or otherwise compensate for) the IQ mismatch to mitigate possible negative system impacts.

[0081] In some operating frequency bands (e.g., in high-frequency bands, sub-THz bands), the network entity 105-a may use a relatively large number of antennas to form narrow beams with relatively high gain and low path loss. However, in such examples, each antenna may be associated with a corresponding IQ modulator (e.g., IQ processing chain) to perform communication with one or more UEs, and each corresponding IQ modulator may be associated with an IQ mismatch error. In such cases, fully compensating for the IQ mismatch may be complex for the network entity 105-a because each IQ modulator introduces a corresponding IQ mismatch error, and the network entity 105-a may support communication with multiple UEs 115, where each UE may include multiple IQ modulators. Thus, as the number of UEs 115 supported by the network entity 105-a increases, the complexity of compensating for the IQ mismatch for each IQ modulator of each UE 115 increases. Compensating for each corresponding IQ mismatch at the network entity 105-a may introduce increased hardware and computational complexity, increased hardware costs, and other challenges.

[0082] In some embodiments, the UE 115-a may compensate (e.g., eliminate, equalize, reduce, or correct) the IQ mismatch introduced by the IQ modulator to reduce the complexity and power overhead at the network entity 105-a. For example, the UE 115-a may be able to perform a process to correct the IQ mismatch with a relatively low impact on performance. For example, the UE 115-a may use various techniques described herein to perform IQ mismatch compensation without additional hardware and with a relatively low impact on power consumption.

[0083] In some cases, IQ mismatch may occur after applying the pre - decoder and before transmission by network entity 105 - a over a communication channel (e.g., via communication link 205). In such a case, UE 115 - a may independently use information about channel H (e.g., channel estimate) and information about the pre - decoder P (e.g., pre - decoder coefficients) to correct the IQ mismatch (e.g., regardless of the pre - decoder dimension, or using a square or non - square pre - decoder). In some cases, UE 115 - a may use separate channel and pre - decoder information (e.g., H and P), rather than the total equivalent channel estimate (e.g., H*P) that combines both channel and pre - decoder information. In some cases, network entity 105 - a may transmit, via communication link 205, a pre - decoder indication 215 (e.g., including pre - decoder coefficients, pre - decoder data, or both) applied to one or more communication signals 210. For example, UE 115 - a may use the information (e.g., pre - decoder coefficients, pre - decoder data, or both) in pre - decoder indication 215 and the received reference signal (e.g., DMRS) to reproduce one or more signals from one or more communication signals 210. In some other cases, UE 115 - a and network entity 105 - a may have previously identified the pre - decoder that can be used (e.g., a static value according to a rule or standard, or a pseudo - random value).

[0084] In some cases, the pre - decoder indication 215 may include an indication of one or more pre - decoder coefficients, duration, slot number, or any combination thereof, applied by the pre - decoder in the pre - decoder indication 215. Additionally or alternatively, the pre - decoder indication 215 may include a first indication of a first pre - decoder and a second indication of a second pre - decoder that may be applied after a threshold duration. For example, UE 115 - a may start processing one or more communication signals 210 according to the first indication of the first pre - decoder received in the pre - decoder indication 215. After the threshold duration, UE 115 - a may process one or more communication signals 210 according to the second indication of the second pre - decoder received in the pre - decoder indication 215. In some other cases, UE 115 - a may receive the pre - decoder indication 215 via a set of downlink pre - decoder data and determine one or more pre - decoder coefficients based on the set of downlink pre - decoder data.

[0085] In some cases, UE 115-a may perform the gain and phase mismatch estimation and cancellation process 220 according to various periodicities. For example, UE 115-a may skip performing the gain and phase mismatch equalization process 220 for each time slot to reduce power cost. In such a case, UE 115-a may use the gain and phase mismatch information obtained in the previous time slot for the current time slot. In some cases, UE 115-a may receive a periodicity indication from network entity 105-a, which indicates the periodicity for UE 115-a to perform the gain and phase mismatch equalization process 220. In such cases, the indicated periodicity may be based on one or more operating factors of network entity 105-a.

[0086] UE 115-a may perform additional processing to perform the gain and phase mismatch equalization process 220 associated with one or more communication signals 210. For example, UE 115-a may use the pre-coder indication 215 and reference signals to reproduce the transmitted signals included in one or more communication signals 210. UE 115-a may perform iterative channel estimation (e.g., using one or more channel estimation methods), and may perform the gain and phase mismatch equalization process 220. After performing the iterative estimation process, UE 115-a may perform gain and phase cancellation according to the techniques described herein. In some examples, UE 115-a may perform gain and phase cancellation and channel equalization simultaneously, which may allow UE 115-a to perform additional processing with a low impact on performance.

[0087] Although the examples described herein describe examples of performing the gain and phase mismatch estimation and cancellation process 220 for downlink signals, the same or similar techniques may be applied to performing the gain and phase mismatch estimation and cancellation for uplink signals.

[0088] Figure 3 An example of a multi-input multi-output (MIMO) system 300 is illustrated that supports a joint gain and phase mismatch canceller and equalizer for downlink assisted by pre-coder signaling according to one or more aspects of the present disclosure. In some examples, MIMO system 300 may be implemented by aspects of wireless communication system 100 or wireless communication system 200. For example, network entity 105, or UE 115, or both may use aspects of MIMO system 300 to generate, process, or transmit IQ communication signals, or any combination thereof.

[0089] The MIMO system 300 may include various signal processing components and multiple signal processing branches (e.g., IQ processing chains). The MIMO system 300 may include, for example, a digital precoder 305 coupled to the multiple signal processing branches. Each signal processing branch may have an IQ modulator 310 (e.g., IQ modulator 310-a, IQ modulator 310-b, etc.) and a transmitter (e.g., transmitter 330-a, transmitter 330-b, transmitter 330-c, transmitter 330-d). In some cases, the network entity 105 may use the MIMO system 300 to wirelessly transmit one or more signals to one or more UEs (e.g., UE 115-b, UE 115-c, UE 115-d, UE 115-e) in the coverage area 110-b via a communication channel 335 (e.g., a specific frequency band or physical channel).

[0090] In some cases, the digital precoder 305 may be associated with one or more inputs including a data vector (or DMRS symbol) mathematically depicted as x(f). The digital precoder 305 may include a precoding matrix mathematically depicted as p(f) or P(f). The entries in the precoding matrix (e.g., the elements of p(f)) may be referred to as precoder coefficients. The digital precoder 305 may apply the precoder coefficients to one or more data signals x(f), which may be mathematically represented as where is the signal to be transmitted to perform signal preprocessing and increase transmit diversity and throughput. Once processed, the digital precoder 305 may generate one or more output signals, which may be one or more transmit data signals mathematically depicted as s(f), where s(f) = I(t) + jQ(t), and I(t) represents the in-phase part of the signal, and Q(t) represents the quadrature part of the signal.

[0091] In some cases, one or more transmit data signals s(f) may be passed to an IQ modulator 310 (e.g., one or more of IQ modulator 310-a, IQ modulator 310-b, IQ modulator 310-c, IQ modulator 310-d). The IQ modulator 310 may include one or more components such as a conjugate block 315, a first filter 320-a (mathematically referred to as k 1 (f) or K 1 (f)), a second filter 320-b (mathematically referred to as k 2 (f) or K 2(f)) and summing component 325. The first filter 320-a and the second filter 320-b can be functions of gain and phase. The IQ modulator 310 can process the transmit data signal s(f) to modulate the transmit data signal with various amplitude and phase configurations. For example, the network entity 105 can use the IQ modulator 310 to generate various different RF signals with unique amplitude and phase modulations.

[0092] However, in some specific implementations, the IQ modulator 310 may introduce errors into the MIMO system 300. For example, the hardware components of the IQ modulator 310 may be non-ideal, or the IQ modulator 310 may generate IQ signals with non-ideal characteristics (e.g., inaccurate relative to the expected output), such as gain and phase errors, or the IQ modulator 310 may have some other defects. Thus, correcting the errors (e.g., IQ gain and phase mismatch errors) may be beneficial for a wireless communication system (e.g., wireless communication system 100, wireless communication system 200, etc.) to improve system performance.

[0093] In some cases, the IQ mismatch errors introduced by the IQ modulator 310 can be identified (e.g., reflected) by adding the conjugate of one or more mirrors of the input transmit signal s(f). For example, the processing performed by the IQ modulator 310 on the transmit data signal s(f) may result in an output transmit data signal s out (f) and can be described as where represents the IQ mismatch error (e.g., the unwanted part, or the part to be eliminated or corrected). For example, a single signal processing branch can have an IQ modulator 310 that can receive (e.g., from the digital precoder 305) the transmit data signal s 1 (f). The IQ modulator 310 can process the signal s 1 (f) with the conjugate block 315, the first filter 320-a, the second filter 320-b, and the summing component 325 to produce an output signal

[0094] One or more transmitters (e.g., transmitter 330-a) can receive the processed transmit data signal s out (f) and transmit the signal via the communication channel 335. The communication channel 335 can change the transmitted data signal s out (f) based on various conditions of the channel. The communication channel 335 can be mathematically referred to as H(f). The effect of the communication channel 335 on the transmitted data signal can be mathematically described as where refers to the signal observed by the receiver (e.g., UE 115-b).

[0095] In some examples, the MIMO system 300 may receive one or more input signals, where nss is the number of input signals in the MIMO system 300. The combination of input signals may be defined as a matrix The digital precoder 305 may receive the combination of input signals and generate one or more data signals for each signal processing branch in the system (e.g., the IQ modulator 310-a and the transmitter 330-a), where ntx is the number of transmitted data signals. The combination of transmitted data signals may also be represented by a matrix As described above, each IQ modulator 310 may have two filters (e.g., the first filter 320-a and the second filter 320-b). The combination of each filter may also be defined by the corresponding matrices and Using such definitions, the matrix expression of the observed signal with IQ mismatch (e.g., FDRSB) may be represented by Equation 1 below:

[0096] y(f) = H(f)(s(f).*k 1 (f)+s * (-f).*k 2 (f))

[0097] In Equation 1, “.*” indicates element-by-element matrix multiplication, and the additive noise term may not be present in the matrix expression. The term s(f).*k 1 (f) may represent the desired part of the observed signal, and s * (-f).*k 2 (f) may represent the error or mismatch.

[0098] One or more UEs 115 in the coverage area 110-b may receive one or more signals generated by the digital precoder 305, one or more IQ modulators, and one or more transmitters via the communication channel 335. According to aspects of the present disclosure, each UE 115 (e.g., instead of or in addition to the network entity 105) may perform gain and phase mismatch estimation and cancellation on the one or more received signals. Since gain and phase mismatch may occur at the IQ modulator 310 (e.g., after the digital precoder 305 but before being transmitted through the communication channel 335), one or more UEs 115 may use information about the digital precoder 305 (e.g., separate from the information about the communication channel 335) to perform gain and phase mismatch estimation and cancellation. In some cases, one or more UEs 115 may receive an indication of the precoder (e.g., precoder coefficients, precoder values) from the network entity 105 and may perform estimation and cancellation based on the indication.

[0099] In some cases, one or more UEs 115 may have a channel equalizer to improve communication (e.g., with network entity 105). In such cases, the UE may employ the channel equalizer to perform additional operations (as described in reference Figure 4 to perform IQ gain and phase mismatch estimation and cancellation. For example, UE 115 may perform IQ gain and phase estimation as well as cancellation and channel equalization simultaneously.

[0100] Figure 4 FIG. 400 illustrates an example of a flow diagram supporting a joint gain and phase mismatch canceller and equalizer for a downlink assisted by precoder signaling in accordance with one or more aspects of the present disclosure. The operations of flow diagram 400 may be implemented by UE 115, network entity 105, or some other device. For example, the operations of the method described by flow diagram 400 may be performed by UE 115 as described in reference Figures 1 to 3 The method described by flow diagram 400 may allow UE 115 or some other device to perform effective gain and phase mismatch (e.g., IQ mismatch) estimation and cancellation. In some cases, for example, UE 115 may use the estimation on DMRS, the estimated communication channel (e.g., physical channel), the precoder, the observed signal, or any combination thereof to perform the method described by flow diagram 400.

[0101] As Figure 3 described, the signal observed at one or more receivers (e.g., one or more UEs 115) may be described by the following equation 2 with additive noise w(f):

[0102] y(f) = H(f)(s(f).*K 1 (f)+s * (-f).*K 2 (f))+w(f)

[0103] It may be noted that a vector can be represented as a diagonal matrix. Thus, the element-wise vector multiplication expression a.*b can be equivalently represented as the matrix multiplication expression diag(b)*a. Applying this property and further simplifying, the above equation can be equivalently written as the following equation 3:

[0104]

[0105] Written in this form, the term can represent the gain and phase mismatch that the UE can estimate and cancel as part of the method described by flow diagram 400. The estimated gain and phase mismatch may be referred to herein as Φ(f), where

[0106] At 405, the method may include using DMRS and pre - decoder coefficients to reproduce the transmitted signal. In some cases, the transmitted signal may be expressed as where s(f) is the transmitted signal (e.g., after pre - decoding and before IQ modulation), P(f) is the applied pre - decoder, and is the DMRS. To enable the UE 115 to reproduce the transmitted signal (e.g., the downlink signal from the network entity 105), the UE 115 may use information regarding the applied pre - decoder P(f) (e.g., applied by the network entity 105) and of.

[0107] At 410, the method may include performing channel estimation on the channel using any channel estimation method (e.g., least - squares estimation, minimum mean - square error estimation, linear, minimum mean - square error estimation, etc.) Using the channel estimation as previously defined, along with the gain and phase mismatch definitions, the above equation can be simplified to Equation 4:

[0108]

[0109] In some examples, the channel estimation may be affected by IQ impairments (e.g., through K 1 ), and thus an interactive channel estimation process may be performed to estimate the channel (e.g., chest ∼ IQ mismatch impairment estimation ∼ chest).

[0110] At 415, the method may include estimating the gain and phase mismatch (e.g., IQ mismatch, FDRSB impairment) by using the estimated channel and the reproduced transmitted signal s(f). For example, the UE 115 (or some other wireless or network device) may use the measurement parameter Q(f) to perform the estimation. The UE 115 may obtain the observed signal y(f) and subtract the desired part to obtain Similarly, using the diagonal matrix property, the equation for Q(f) can be expanded to the following Equation 5:

[0111]

[0112] And may be further simplified based on the following Equation 6:

[0113]

[0114] such that the measurement parameter Q(f) can be expressed as Q(f)=U(f)·Φ(f)+w(f). The UE 115 can then calculate the gain and phase mismatch parameters using the following Equations 7 and 8 and

[0115]

[0116] In some examples, due to the channel estimation at 410 may depend on the parameters of the IQ modulator (K 1 (f)), and 410 and 415 may be performed iteratively as shown at 420. For example, the UE may perform the operations described at 415 to obtain an estimate of the gain and phase mismatch. Then, the UE may follow 420 to perform channel estimation at 410 and use the additional information obtained in the estimate performed at 415. The UE or some other device may follow 420 and, thereby, repeat 410 and 415 one or more times, or may not follow 420 and proceed to 425.

[0117] In some cases, the UE 115 may communicate to the network entity 105 whether the gain and phase estimation was successful or not. For example, the UE 115 may determine that the estimation performed at 415 was not successful and may request the network entity 105 to keep the pre - decoder the same until the UE 115 successfully performs the gain and phase estimation.

[0118] At 425, the method may include performing gain and phase mismatch cancellation and equalization. Continuing from Equation 4, reproduced as follows:

[0119]

[0120] And recalling that the transmitted signal s(f) is the product of the pre - decoder and the input signal, s(f)=p(f)x(f), the above equation can be equivalently written as Equation 9:

[0121]

[0122] Furthermore, the conjugate mirror of y(f) can be y * (-f) and can be written as Equation 10:

[0123]

[0124] To represent cancellation and equalization, the terms x(±f), y(±f), and w(±f) can be defined as:

[0125]

[0126] For example, in the presence of four receivers, y(f), y * (-f), and y(±f) can be defined as follows:

[0127]

[0128] Using the above structures and definitions, the mathematical expressions for y(f) and y * (-f) can be condensed into a single matrix equation 11:

[0129]

[0130] For simplicity, can be defined as:

[0131]

[0132] And equation 11 can be simplified to equation 12:

[0133]

[0134] For example, UE 115 can evaluate equation 12 during 425 (e.g., using an advanced equalizer) to cancel and equalize gain and phase mismatches. In such examples, it can be assumed that: y(f) ∈ (nrx,1), x(f) ∈ (nss,1), p(f) ∈ (ntx,nss), s(f) ∈ (ntx,1), H(f) ∈ (nrx,ntx), Φ(f) ∈ (ntx,1), y(±f) ∈ (2·nrx,1), w(±f) ∈ (2·nrx,1), and x(±f) ∈ (2·nss,1).

[0135] In some cases, UE 115 can perform 425 without any additional processing hardware (e.g., an advanced equalizer). Additionally or alternatively, UE 115 can calculate the channel equalization parameters using the following equations 13 and 14 and

[0136]

[0137] Thereby, at 425, the processing can move from the receiver antenna domain to the layer domain and simultaneously perform IQ gain and phase mismatch cancellation (e.g., in the same process).

[0138] Figure 5 Illustrates an example of a process flow 500 that supports a joint gain and phase mismatch canceller and equalizer for a downlink assisted by precoder signaling in accordance with one or more aspects of the present disclosure. In some examples, process flow 500 can implement aspects of wireless communication system 100 or wireless communication system 200. For example, process flow 500 can support a configuration for indicating a precoder to a UE for gain and phase mismatch estimation and cancellation of an associated communication signal.

[0139] In the following description of process flow 500, operations between UE 115-f and network entity 105-b may be sent in an order different from the order shown, or other operations may be added to or removed from process flow 500. For example, some operations may also be omitted from process flow 500, or UE 115-f and network entity 105-b may perform in a different order or at different times, and other operations may be added to process flow 500. Although UE 115-f and network entity 105-b are shown as performing the operations of process flow 500, some aspects of some operations may also be performed by one or more other wireless or network devices.

[0140] At 505, UE 115-f may receive a downlink message via a downlink channel, the downlink message including an indication of a pre-coder applied to one or more downlink signals. For example, UE 115-f may use at least one DMRS and a pre-coder to receive one or more downlink signals, where the one or more downlink signals are at least partially mismatched in gain and phase.

[0141] In some cases, UE 115-f may receive an indication of the duration, time slot number, or both for which the pre-coder is applied to one or more downlink signals. Additionally or alternatively, UE 115-f may receive a pre-coder indication via a set of downlink pre-coded data, where UE 115-f may determine one or more pre-coder coefficients based on the set of downlink pre-coded data. In some cases, the indication of the pre-coder may include a first indication of a first pre-coder. UE 115-f may receive a second indication of a second pre-coder to be applied to one or more downlink signals after a threshold duration via the first indication of the first pre-coder.

[0142] In some cases, UE 115-f may apply one or more pre-coder coefficients to one or more downlink signals. For example, UE 115-f may use a reference signal (e.g., DMRS) and one or more pre-coder coefficients to reproduce the transmitted signal. In some cases, the value of the pre-coder may include a static value or a pseudo-random value. Additionally or alternatively, UE 115-f may perform a gain and phase mismatch equalization process based on the value of the pre-coder. In some other cases, UE 115-f may perform a gain and phase mismatch equalization process according to the second pre-coder received at 505.

[0143] At 510, UE 115-f may receive a periodic indication from network entity 105-b that indicates the periodicity of the gain and phase mismatch equalization process that UE 115-f is to perform based on one or more operating factors of network entity 105-b. For example, in some cases, the gain and phase mismatch may have a low rate of change, and thus, UE 115-f may not perform gain and phase estimation and equalization for each time slot (e.g., to reduce power cost or reduce processing resource usage). For example, UE 115-f may be able to use the gain and phase mismatch information obtained during one or more previous time slots to perform the estimation and equalization for the current time slot.

[0144] At 515, UE 115-f may perform an iterative channel estimation process to estimate the downlink channel. In some cases, UE 115-f may perform an iterative channel estimation process to estimate the physical channel associated with one or more downlink signals using at least one DMRS. UE 115-f may estimate the estimated gain and phase mismatch based on the estimated physical channel, the precoder, or both.

[0145] At 520, UE 115-f may estimate the gain and phase mismatch of one or more downlink signals based at least in part on the estimated downlink channel and the precoder. For example, network entity 105-b may use an IQ modulator after applying the precoder and before transmitting the signal to UE 115-f. At 520, UE 115-f may estimate the gain and phase mismatch (e.g., IQ impairment) in order to perform a gain and phase cancellation and equalization process. In some cases, the estimated gain and phase mismatch may be a frequency-dependent gain and phase mismatch.

[0146] At 525, UE 115-f may perform at least a second channel estimation process based on the estimated gain and phase mismatch (e.g., at 520). For example, UE 115-f may perform a first channel estimation process at 515 and a first gain and phase mismatch estimation at 520. However, the gain and phase mismatch performed at 520 may further affect the channel estimation. Thus, UE 115-f may perform a second channel estimation process to account for the effect of the gain and phase mismatch performed at 520.

[0147] At 530, UE 115-f may perform at least a second gain and phase mismatch estimation process based on the second channel estimation process at 525. Additionally or alternatively, UE 115-f may continue to perform more channel estimation and gain and phase mismatch estimation processes to provide a more accurate channel estimation.

[0148] At 535, UE 115-f may perform a gain and phase mismatch equalization process to equalize the estimated gain and phase mismatch of one or more downlink signals based on the estimated downlink channel and the pre-coder. In some cases, UE 115-f may reproduce one or more downlink signals based on at least one DMRS received at 505 and the pre-coder for the gain and phase mismatch equalization process.

[0149] In some cases, UE 115-f may perform a gain and phase mismatch equalization process and simultaneously equalize the estimated gain and phase mismatch of one or more downlink signals. Additionally or alternatively, UE 115-f may cancel at least a portion of the estimated gain and phase mismatch. In such cases, the gain and phase mismatch equalization process may include an IQ mismatch equalization process.

[0150] At 540, UE 115-f may receive one or more equalized downlink signals according to the gain and phase mismatch equalization process. For example, UE 115-f may apply the calculations performed during the process at 535 to the signals received at 540. Thus, UE 115-f may cancel the gain and phase mismatch of one or more received signals at 540 based on the process performed at 535.

[0151] Figure 6 Block diagram 600 illustrates a device 605 supporting a joint gain and phase mismatch eliminator and equalizer for downlink assisted by pre-coder signaling in accordance with one or more aspects of the present disclosure. Device 605 may be an example of aspects of UE 115 as described herein. Device 605 may include a receiver 610, a transmitter 615, and a communication manager 620. Device 605 may also include a processor. Each of these components may communicate with each other (e.g., via one or more buses).

[0152] Receiver 610 may provide components 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 a joint gain and phase mismatch eliminator and equalizer for downlink assisted by pre-coder signaling). The information may be passed to other components of device 605. Receiver 610 may utilize a single antenna or an array of multiple antennas.

[0153] The transmitter 615 can provide components for transmitting signals generated by other components of the device 605. For example, the transmitter 615 can be a component that transmits 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 the joint gain and phase mismatch canceler and equalizer for the downlink assisted by pre-coder signaling). In some examples, the transmitter 615 can be co-located with the receiver 610 in a transceiver module. The transmitter 615 can utilize a single antenna or an array of multiple antennas.

[0154] The communication manager 620, the receiver 610, the transmitter 615, or various combinations thereof or their various components can be examples of components for performing various aspects of the joint gain and phase mismatch canceler and equalizer for the downlink assisted by pre-coder signaling as described herein. For example, the communication manager 620, the receiver 610, the transmitter 615, or various combinations thereof or their components can support methods for performing one or more of the functions described herein.

[0155] In some examples, the communication manager 620, the receiver 610, the transmitter 615, or various combinations thereof or their components can be implemented in hardware (e.g., in a communication management circuit). The hardware can 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, discrete hardware components, or any combination thereof that are configured to or otherwise support components for performing the functions described in this disclosure. In some examples, the processor and the memory coupled to the processor can be configured to perform one or more of the functions described herein (e.g., by the processor executing instructions stored in the memory).

[0156] Additionally or alternatively, in some examples, the communication manager 620, the receiver 610, the transmitter 615, or various combinations thereof or their components can be implemented in code executed by a processor (e.g., implemented as communication management software or firmware). If implemented in code executed by a processor, the functions of the communication manager 620, the receiver 610, the transmitter 615, or various combinations thereof or their components can be executed by a general purpose processor, a DSP, a CPU, an ASIC, an FPGA, a microcontroller, or any combination of these or other programmable logic devices that are configured to or otherwise support components for performing the functions described in this disclosure.

[0157] In some examples, the communication manager 620 may be configured to use or otherwise cooperate with the receiver 610, the transmitter 615, or both to perform various operations (e.g., receive, obtain, monitor, output, transmit). For example, the communication manager 620 may receive information from the receiver 610, convey information to the transmitter 615, or integrate in combination with the receiver 610, the transmitter 615, or both to obtain information, output information, or perform various other operations as described herein.

[0158] According to examples as disclosed herein, the communication manager 620 may support wireless communication at the UE. For example, the communication manager 620 may be configured to or otherwise support components for receiving a downlink message via a downlink channel that includes an indication of a pre - decoder applied to one or more downlink signals. The communication manager 620 may be configured to or otherwise support components for receiving one or more downlink signals using at least one DMRS and a pre - decoder, where the one or more downlink signals are at least partially mismatched in gain and phase. The communication manager 620 may be configured to or otherwise support components for performing an iterative channel estimation process to estimate a downlink channel. The communication manager 620 may be configured to or otherwise support components for performing a gain and phase mismatch equalization process at the UE to equalize an estimated gain and phase mismatch of one or more downlink signals based on the estimated downlink channel and the pre - decoder. The communication manager 620 may be configured to or otherwise support components for receiving one or more equalized downlink signals according to the gain and phase mismatch equalization process.

[0159] By including or configuring the communication manager 620 according to examples as described herein, the device 605 (e.g., a processor that controls or otherwise is coupled with the receiver 610, the transmitter 615, the communication manager 620, or a combination thereof) may support techniques for reducing design complexity and more efficiently utilizing communication resources.

[0160] Figure 7 Block diagram 700 illustrates a device 705 that supports a joint gain and phase mismatch canceller and equalizer for a downlink assisted by pre - decoder signaling, in accordance with one or more aspects of the present disclosure. The device 705 may be an example of aspects of the device 605 or the UE 115 as described herein. The device 705 may include a receiver 710, a transmitter 715, and a communication manager 720. The device 705 may also include a processor. Each of these components may communicate with each other (e.g., via one or more buses).

[0161] The receiver 710 may provide components for receiving information associated with various information channels (e.g., control channels, data channels, information channels associated with a joint gain and phase mismatch canceller and equalizer for a downlink assisted by pre-coder signaling), such as packets, user data, control information, or any combination thereof. The information may be passed to other components of the device 705. The receiver 710 may utilize a single antenna or an array of multiple antennas.

[0162] The transmitter 715 may provide components for transmitting signals generated by other components of the device 705. For example, the transmitter 715 may transmit components of information associated with various information channels (e.g., control channels, data channels, information channels associated with a joint gain and phase mismatch canceller and equalizer for a downlink assisted by pre-coder signaling), such as packets, user data, control information, or any combination thereof. In some examples, the transmitter 715 may be co-located with the receiver 710 in a transceiver module. The transmitter 715 may utilize a single antenna or an array of multiple antennas.

[0163] The device 705 or its various components may be examples of components for performing aspects of a joint gain and phase mismatch canceller and equalizer for a downlink assisted by pre-coder signaling as described herein. For example, the communication manager 720 may include a pre-coder component 725, a downlink signal management component 730, a channel estimation component 735, a mismatch equalization component 740, or any combination thereof. The communication manager 720 may be an example of aspects of the communication manager 620 as described herein. In some examples, the communication manager 720 or its various components may be configured to perform various operations (e.g., receive, obtain, monitor, output, transmit) using or otherwise in cooperation with the receiver 710, the transmitter 715, or both. For example, the communication manager 720 may receive information from the receiver 710, convey information to the transmitter 715, or integrate in combination with the receiver 710, the transmitter 715, or both to obtain information, output information, or perform various other operations as described herein.

[0164] According to an example as disclosed herein, the communication manager 720 may support wireless communication at a UE. A predecoder component 725 may be configured to or otherwise support a component for receiving a downlink message via a downlink channel that includes an indication of a predecoder applied to one or more downlink signals. A downlink signal management component 730 may be configured to or otherwise support a component for receiving one or more downlink signals using at least one DMRS and a predecoder, where the one or more downlink signals are at least partially mismatched in gain and phase. A channel estimation component 735 may be configured to or otherwise support a component for performing an iterative channel estimation process to estimate a downlink channel. A mismatch equalization component 740 may be configured to or otherwise support a component for performing a gain and phase mismatch equalization process at the UE to equalize an estimated gain and phase mismatch of one or more downlink signals based on the estimated downlink channel and the predecoder. The downlink signal management component 730 may be configured to or otherwise support a component for receiving one or more equalized downlink signals according to the gain and phase mismatch equalization process.

[0165] Figure 8 Block diagram 800 illustrates a communication manager 820 supporting a joint gain and phase mismatch canceller and equalizer for a downlink assisted by predecoder signaling, according to one or more aspects of the present disclosure. The communication manager 820 may be an example of aspects of the communication manager 620, the communication manager 720, or both as described herein. The communication manager 820 or its various components may be examples of components for performing various aspects of a joint gain and phase mismatch canceller and equalizer for a downlink assisted by predecoder signaling as described herein. For example, the communication manager 820 may include a predecoder component 825, a downlink signal management component 830, a channel estimation component 835, a mismatch equalization component 840, a mismatch estimation component 845, a predecoder application component 850, a mismatch cancellation component 855, a mismatch equalization and cancellation component 860, a signal reproduction component 865, a periodic component 870, or any combination thereof. Each of these components may communicate directly or indirectly with each other (e.g., via one or more buses).

[0166] According to examples disclosed herein, a communication manager 820 may support wireless communication at a UE. A pre - decoder component 825 may be configured to or otherwise support a component for receiving a downlink message via a downlink channel that includes an indication of a pre - decoder applied to one or more downlink signals. A downlink signal management component 830 may be configured to or otherwise support a component for receiving one or more downlink signals using at least one DMRS and a pre - decoder, where the one or more downlink signals are at least partially mismatched in gain and phase. A channel estimation component 835 may be configured to or otherwise support a component for performing an iterative channel estimation process to estimate a downlink channel. A mismatch equalization component 840 may be configured to or otherwise support a component for performing a gain and phase mismatch equalization process at the UE to equalize an estimated gain and phase mismatch of one or more downlink signals based on the estimated downlink channel and the pre - decoder. In some examples, the downlink signal management component 830 may be configured to or otherwise support a component for receiving one or more equalized downlink signals according to the gain and phase mismatch equalization process.

[0167] In some examples, the channel estimation component 835 may be configured to or otherwise support a component for performing an iterative channel estimation process to estimate a physical channel associated with one or more downlink signals using at least one DMRS. In some examples, a mismatch estimation component 845 may be configured to or otherwise support a component for estimating an estimated gain and phase mismatch based on the estimated physical channel, the pre - decoder, or both.

[0168] In some examples, to support receiving one or more downlink signals, a pre - decoder application component 850 may be configured to or otherwise support a component for applying one or more pre - decoder coefficients to one or more downlink signals.

[0169] In some examples, to support performing an iterative channel estimation process, the channel estimation component 835 may be configured to or otherwise support a component for performing a first channel estimation process. In some examples, to support performing an iterative channel estimation process, the mismatch equalization component 840 may be configured to or otherwise support a component for performing a gain and phase mismatch equalization process. In some examples, to support performing an iterative channel estimation process, the channel estimation component 835 may be configured to or otherwise support a component for performing at least a second channel estimation process based on the estimated gain and phase mismatch.

[0170] In some examples, to support performing a gain and phase mismatch equalization process, a mismatch cancellation component 855 may be configured to or otherwise support a component for canceling at least a portion of the estimated gain and phase mismatch.

[0171] In some examples, to support receiving a downlink message that includes an indication of a pre - decoder, the downlink signal management component 830 may be configured to or otherwise support a component for receiving an indication of the pre - decoder via a set of downlink pre - coded data, wherein the one or more pre - decoder coefficients are determined based on the set of downlink pre - coded data.

[0172] In some examples, the mismatch equalization and cancellation component 860 may be configured to or otherwise support a component for performing a gain and phase mismatch equalization process and simultaneously equalizing the estimated gain and phase mismatches of the one or more downlink signals.

[0173] In some examples, to support receiving one or more downlink signals, the signal reproduction component 865 may be configured to or otherwise support a component for reproducing one or more downlink signals based on at least one DMRS and a pre - decoder for a gain and phase mismatch equalization process.

[0174] In some examples, to support receiving an indication of a pre - decoder, the pre - decoder component 825 may be configured to or otherwise support a component for receiving an indication of the duration, time - slot number, or both for which the pre - decoder is applied to one or more downlink signals.

[0175] In some examples, the value of the pre - decoder includes a static value or a pseudo - random value, and the mismatch equalization component 840 may be configured to or otherwise support a component for performing a gain and phase mismatch equalization process based on the value of the pre - decoder.

[0176] In some examples, the indication of the pre - decoder includes a first indication of a first pre - decoder, and the pre - decoder component 825 may be configured to or otherwise support a component for receiving a second indication of a second pre - decoder to be applied to one or more downlink signals after a threshold duration via the first indication of the first pre - decoder. In some examples, the indication of the pre - decoder includes a first indication of a first pre - decoder, and the mismatch equalization component 840 may be configured to or otherwise support a component for performing a gain and phase mismatch equalization process according to the second pre - decoder.

[0177] In some examples, the periodicity component 870 may be configured to or otherwise support a component for receiving a periodic indication from a network entity, the periodic indication indicating the periodicity for which the UE is to perform a gain and phase mismatch equalization process based on one or more operating factors of the network entity.

[0178] In some examples, the gain and phase mismatch equalization process includes an IQ mismatch equalization process.

[0179] In some examples, the estimated gain and phase mismatches are frequency-dependent gain and phase mismatches.

[0180] Figure 9 FIG. 900 is a schematic diagram of a system 900 including a device 905 that supports a joint gain and phase mismatch canceller and equalizer for downlink assisted by pre-coder signaling, in accordance with one or more aspects of the present disclosure. The device 905 can be an example of or include components of the device 605, the device 705, or the UE 115 as described herein. The device 905 can communicate (e.g., wirelessly) with one or more network entities 105, one or more UEs 115, or any combination thereof. The device 905 can include components for two-way voice and data communication, 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, code 935, and a processor 940. These components can communicate electronically via one or more buses (e.g., bus 945) or otherwise (e.g., operatively, communicatively, functionally, electronically, electrically) coupled.

[0181] The I / O controller 910 can manage input and output signals of the device 905. The I / O controller 910 can also manage peripheral devices not integrated into the device 905. In some cases, the I / O controller 910 can represent a physical connection or port to an external peripheral device. In some cases, the I / O controller 910 can utilize an operating system, such as or another known operating system. Additionally or alternatively, the I / O controller 910 can represent, or interact with, a modem, a keyboard, a mouse, a touch screen, or similar device. In some cases, the I / O controller 910 can be implemented as part of a processor (such as the processor 940). In some cases, a user can interact with the device 905 via the I / O controller 910 or via hardware components controlled by the I / O controller 910.

[0182] In some cases, device 905 may include a single antenna 925. However, in some other cases, device 905 may have more than one antenna 925, and the more than one antenna may be capable of concurrently sending or receiving multiple wireless transmissions. Transceiver 915 may communicate bidirectionally via one or more antennas 925, wired or wireless links, as described herein. For example, transceiver 915 may represent a wireless transceiver and may communicate bidirectionally with another wireless transceiver. Transceiver 915 may also include a modem that is configured to modulate packets for providing the modulated packets to one or more antennas 925 for transmission and to demodulate packets received from one or more antennas 925. Transceiver 915 or transceiver 915 and one or more antennas 925 may be examples of transmitter 615, transmitter 715, receiver 610, receiver 710, or any combination thereof or their components as described herein.

[0183] Memory 930 may include random access memory (RAM) and read only memory (ROM). Memory 930 may store computer-readable, computer-executable code 935 that includes instructions that, when executed by processor 940, cause device 905 to perform the various functions described herein. Code 935 may be stored in a non-transitory computer-readable medium, such as system memory or another type of memory. In some cases, code 935 may not be directly executable by processor 940 but may, for example, when compiled and executed, cause the computer to perform the functions described herein. In some cases, among other things, memory 930 may also contain a basic input / output system (BIOS) that may control basic hardware or software operations, such as interactions with peripheral components or devices.

[0184] Processor 940 may include intelligent hardware devices (e.g., general purpose processors, DSPs, CPUs, microcontrollers, ASICs, FPGAs, programmable logic devices, discrete gate or transistor logic components, discrete hardware components, or any combination thereof). In some cases, 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 processor 940. Processor 940 may be configured to execute computer-readable instructions stored in a memory (e.g., memory 930) to cause device 905 to perform various functions (e.g., functions or tasks of a joint gain and phase mismatch canceller and equalizer that support downlink assisted by predecoder signaling). For example, device 905 or components of device 905 may include processor 940 and memory 930 coupled or coupled to processor 940, and processor 940 and memory 930 are configured to perform the various functions described herein.

[0185] According to examples disclosed herein, communication manager 920 may support wireless communication at a UE. For example, communication manager 920 may be configured to or otherwise support components for receiving a downlink message via a downlink channel that includes an indication of a pre-coder applied to one or more downlink signals. Communication manager 920 may be configured to or otherwise support components for receiving one or more downlink signals using at least one DMRS and the pre-coder, where the one or more downlink signals are at least partially mismatched in gain and phase. Communication manager 920 may be configured to or otherwise support components for performing an iterative channel estimation process to estimate a downlink channel. Communication manager 920 may be configured to or otherwise support components for performing a gain and phase mismatch equalization process at the UE to equalize an estimated gain and phase mismatch of one or more downlink signals based on the estimated downlink channel and the pre-coder. Communication manager 920 may be configured to or otherwise support components for receiving one or more equalized downlink signals according to the gain and phase mismatch equalization process.

[0186] By including or configuring communication manager 920 according to examples described herein, device 905 may support techniques for reduced system complexity, more efficient utilization of communication resources, improved efficiency among devices, and improved processing power utilization.

[0187] In some examples, communication manager 920 may be configured to use or otherwise cooperate with transceiver 915, one or more antennas 925, or any combination thereof to perform various operations (e.g., receive, monitor, transmit). Although communication manager 920 is illustrated as a separate component, in some examples, one or more functions described with reference to communication manager 920 may be supported or performed by processor 940, memory 930, code 935, or any combination thereof. For example, code 935 may include instructions executable by processor 940 to cause device 905 to perform aspects of a joint gain and phase mismatch canceller and equalizer for a downlink assisted by pre-coder signaling as described herein, or processor 940 and memory 930 may otherwise be configured to perform or support such operations.

[0188] Figure 10 A flowchart of an example method 1000 that illustrates support for a joint gain and phase mismatch canceller and equalizer for a downlink assisted by pre-coder signaling in accordance with one or more aspects of the present disclosure is illustrated. Operations of method 1000 may be implemented by a UE or components thereof as described herein. For example, operations of method 1000 may be performed by a UE as referenced Figures 1 to 9performed by the described UE 115. In some examples, the UE may execute an instruction set to control functional elements of the UE to perform the described functions. Additionally or alternatively, the UE may use dedicated hardware to perform aspects of the described functions.

[0189] At 1005, the method may include receiving a downlink message via a downlink channel, the downlink message including an indication of a pre - decoder applied to one or more downlink signals. The operation of 1005 may be performed in accordance with examples disclosed herein. In some examples, aspects of the operation of 1005 may be performed by a pre - decoder component 825 as described Figure 8 above.

[0190] At 1010, the method may include receiving one or more downlink signals using at least one DMRS and a pre - decoder, wherein the one or more downlink signals are at least partially mismatched in gain and phase. The operation of 1010 may be performed in accordance with examples disclosed herein. In some examples, aspects of the operation of 1010 may be performed by a downlink signal management component 830 as described Figure 8 above.

[0191] At 1015, the method may include performing an iterative channel estimation process to estimate the downlink channel. The operation of 1015 may be performed in accordance with examples disclosed herein. In some examples, aspects of the operation of 1015 may be performed by a channel estimation component 835 as described Figure 8 above.

[0192] At 1020, the method may include performing a gain and phase mismatch equalization process at the UE to equalize the estimated gain and phase mismatch of one or more downlink signals based on the estimated downlink channel and the pre - decoder. The operation of 1020 may be performed in accordance with examples disclosed herein. In some examples, aspects of the operation of 1020 may be performed by a mismatch equalization component 840 as described Figure 8 above.

[0193] At 1025, the method may include receiving one or more equalized downlink signals in accordance with the gain and phase mismatch equalization process. The operation of 1025 may be performed in accordance with examples disclosed herein. In some examples, aspects of the operation of 1025 may be performed by a downlink signal management component 830 as described Figure 8 above.

[0194] Figure 11Illustrated is a flowchart of a method 1100 that exemplifies a joint gain and phase mismatch canceller and equalizer for downlink assisted by precoder signaling in accordance with one or more aspects of the present disclosure. Operations of method 1100 may be implemented by a UE or its components as described herein. For example, operations of method 1100 may be performed by UE 115 as described with reference to Figures 1 to 9 In some examples, the UE may execute an instruction set to control functional elements of the UE to perform the described functions. Additionally or alternatively, the UE may use dedicated hardware to perform aspects of the described functions.

[0195] At 1105, the method may include receiving a downlink message via a downlink channel, the downlink message including an indication of a precoder applied to one or more downlink signals. The operation of 1105 may be performed in accordance with examples disclosed herein. In some examples, aspects of the operation of 1105 may be performed by a precoder component 825 as described with reference to Figure 8 At 1110, the method may include receiving one or more downlink signals using at least one DMRS and a precoder, wherein the one or more downlink signals are at least partially mismatched in gain and phase. The operation of 1110 may be performed in accordance with examples disclosed herein. In some examples, aspects of the operation of 1110 may be performed by a downlink signal management component 830 as described with reference to

[0196] At 1115, the method may include performing an iterative channel estimation process to estimate the downlink channel. The operation of 1115 may be performed in accordance with examples disclosed herein. In some examples, aspects of the operation of 1115 may be performed by a channel estimation component 835 as described with reference to Figure 8 At 1120, the method may include performing an iterative channel estimation process to estimate a physical channel associated with one or more downlink signals using at least one DMRS. The operation of 1120 may be performed in accordance with examples disclosed herein. In some examples, aspects of the operation of 1120 may be performed by a channel estimation component 835 as described with reference to

[0197] At 1125, the method may include performing a gain and phase mismatch equalization process at the UE to equalize the estimated gain and phase mismatch of one or more downlink signals based on the estimated downlink channel and the precoder. The operation of 1125 may be performed in accordance with examples disclosed herein. In some examples, aspects of the operation of 1125 may be performed by a component as described with reference to Figure 8 At 1125, the method may include performing a gain and phase mismatch equalization process at the UE to equalize the estimated gain and phase mismatch of one or more downlink signals based on the estimated downlink channel and the precoder. The operation of 1125 may be performed in accordance with examples disclosed herein. In some examples, aspects of the operation of 1125 may be performed by a component as described with reference to

[0198] At 1120, the method may include performing an iterative channel estimation process to estimate a physical channel associated with one or more downlink signals using at least one DMRS. The operation of 1120 may be performed in accordance with examples disclosed herein. In some examples, aspects of the operation of 1120 may be performed by a channel estimation component 835 as described with reference to Figure 8 At 1120, the method may include performing an iterative channel estimation process to estimate a physical channel associated with one or more downlink signals using at least one DMRS. The operation of 1120 may be performed in accordance with examples disclosed herein. In some examples, aspects of the operation of 1120 may be performed by a channel estimation component 835 as described with reference to

[0199] At 1125, the method may include performing a gain and phase mismatch equalization process at the UE to equalize the estimated gain and phase mismatch of one or more downlink signals based on the estimated downlink channel and the precoder. The operation of 1125 may be performed in accordance with examples disclosed herein. In some examples, aspects of the operation of 1125 may be performed by a component as described with reference to Figure 8performed by the mismatch equalization component 840 described above.

[0200] At 1130, the method may include estimating an estimated gain and phase mismatch based on the estimated physical channel, the pre - decoder, or both. The operation of 1130 may be performed according to the examples disclosed herein. In some examples, aspects of the operation of 1130 may be performed by the mismatch estimation component 845 described with reference to Figure 8 the above - described mismatch estimation component 845.

[0201] At 1135, the method may include receiving one or more equalized downlink signals according to a gain and phase mismatch equalization process. The operation of 1135 may be performed according to the examples disclosed herein. In some examples, aspects of the operation of 1135 may be performed by the downlink signal management component 830 described with reference to Figure 8 the above - described downlink signal management component 830.

[0202] Figure 12 FIG. 14 illustrates a flowchart of a method 1200 for a joint gain and phase mismatch canceller and equalizer for a downlink assisted by pre - decoder signaling in accordance with one or more aspects of the present disclosure. The operations of method 1200 may be implemented by a UE or its components as described herein. For example, the operations of method 1200 may be performed by the UE 115 described with reference to Figures 1 to 9 the above - described UE 115. 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 aspects of the described functions.

[0203] At 1205, the method may include receiving a downlink message via a downlink channel, the downlink message including an indication of a pre - decoder applied to one or more downlink signals. The operation of 1205 may be performed according to the examples disclosed herein. In some examples, aspects of the operation of 1205 may be performed by the pre - decoder component 825 described with reference to Figure 8 the above - described pre - decoder component 825.

[0204] At 1210, the method may include receiving one or more downlink signals using at least one DMRS and a pre - decoder, wherein the one or more downlink signals are at least partially mismatched in gain and phase. The operation of 1210 may be performed according to the examples disclosed herein. In some examples, aspects of the operation of 1210 may be performed by the downlink signal management component 830 described with reference to Figure 8 the above - described downlink signal management component 830.

[0205] At 1215, the method can include applying one or more precoder coefficients to one or more downlink signals. The operation at 1215 can be performed according to the examples disclosed herein. In some examples, aspects of the operation at 1215 can be performed by a precoder application component 850 as described with reference to Figure 8 The precoder application component 850 described above.

[0206] At 1220, the method can include performing an iterative channel estimation process to estimate the downlink channel. The operation at 1220 can be performed according to the examples disclosed herein. In some examples, aspects of the operation at 1220 can be performed by a channel estimation component 835 as described with reference to Figure 8 The channel estimation component 835 described above.

[0207] At 1225, the method can include performing a gain and phase mismatch equalization process at the UE to equalize the estimated gain and phase mismatch of one or more downlink signals based on the estimated downlink channel and the precoder. The operation at 1225 can be performed according to the examples disclosed herein. In some examples, aspects of the operation at 1225 can be performed by a mismatch equalization component 840 as described with reference to Figure 8 The mismatch equalization component 840 described above.

[0208] At 1230, the method can include receiving one or more equalized downlink signals according to the gain and phase mismatch equalization process. The operation at 1230 can be performed according to the examples disclosed herein. In some examples, aspects of the operation at 1230 can be performed by a downlink signal management component 830 as described with reference to Figure 8 The downlink signal management component 830 described above.

[0209] An overview of aspects of the present disclosure is provided below:

[0210] Aspect 1: A method for wireless communication at a UE, the method including: receiving, via a downlink channel, a downlink message including an indication of a precoder applied to one or more downlink signals; receiving the one or more downlink signals using at least one DMRS and the precoder, wherein the one or more downlink signals are at least partially mismatched in gain and phase; performing an iterative channel estimation process to estimate the downlink channel; performing a gain and phase mismatch equalization process at the UE to equalize the estimated gain and phase mismatch of the one or more downlink signals based at least in part on the estimated downlink channel and the precoder; and receiving one or more equalized downlink signals according to the gain and phase mismatch equalization process.

[0211] Aspect 2: The method according to aspect 1, the method further comprising: performing the iterative channel estimation process to estimate a physical channel associated with the one or more downlink signals using the at least one DMRS; and estimating the estimated gain and phase mismatch based at least in part on the estimated physical channel, the pre - decoder, or both.

[0212] Aspect 3: The method according to any one of aspects 1 to 2, wherein the indication of the pre - decoder comprises one or more pre - decoder coefficients, and wherein receiving the one or more downlink signals further comprises: applying the one or more pre - decoder coefficients to the one or more downlink signals.

[0213] Aspect 4: The method according to any one of aspects 1 to 3, wherein performing the iterative channel estimation process further comprises: performing a first channel estimation process; performing the gain and phase mismatch equalization process; and performing at least a second channel estimation process based at least in part on the estimated gain and phase mismatch.

[0214] Aspect 5: The method according to any one of aspects 1 to 4, wherein performing the gain and phase mismatch equalization process further comprises: eliminating at least a portion of the estimated gain and phase mismatch.

[0215] Aspect 6: The method according to any one of aspects 1 to 5, wherein receiving the downlink message comprising the indication of the pre - decoder further comprises: receiving the indication of the pre - decoder via a set of downlink pre - coded data, wherein the one or more pre - decoder coefficients are determined based at least in part on the set of downlink pre - coded data.

[0216] Aspect 7: The method according to any one of aspects 1 to 6, the method further comprising: performing the gain and phase mismatch equalization process and simultaneously equalizing the estimated gain and phase mismatch of the one or more downlink signals.

[0217] Aspect 8: The method according to any one of aspects 1 to 7, wherein receiving the one or more downlink signals further comprises: reproducing the one or more downlink signals based at least in part on the at least one DMRS and the pre - decoder for the gain and phase mismatch equalization process.

[0218] Aspect 9: The method according to any one of aspects 1 to 8, wherein receiving the indication of the pre - decoder further comprises: receiving an indication of the duration, time slot number, or both for which the pre - decoder is applied to the one or more downlink signals.

[0219] Aspect 10: The method according to any one of Aspects 1 to 9, wherein the value of the pre - decoder comprises a static value or a pseudo - random value, and the method further comprises: performing the gain and phase mismatch equalization process at least partially based on the value of the pre - decoder.

[0220] Aspect 11: The method according to any one of Aspects 1 to 10, wherein the indication of the pre - decoder comprises a first indication of a first pre - decoder, and the method further comprises: receiving, via the first indication of the first pre - decoder, a second indication of a second pre - decoder to be applied to the one or more downlink signals after a threshold duration; and performing the gain and phase mismatch equalization process according to the second pre - decoder.

[0221] Aspect 12: The method according to any one of Aspects 1 to 11, the method further comprises: receiving a periodic indication from a network entity, the periodic indication indicating the periodicity for the UE to perform the gain and phase mismatch equalization process at least partially based on one or more operating factors of the network entity.

[0222] Aspect 13: The method according to any one of Aspects 1 to 12, wherein the gain and phase mismatch equalization process comprises an in - phase quadrature (IQ) mismatch equalization process.

[0223] Aspect 14: The method according to any one of Aspects 1 to 13, wherein the estimated gain and phase mismatch is a frequency - dependent gain and phase mismatch.

[0224] Aspect 15: An apparatus for wireless communication at a UE, the apparatus comprises: 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 the method according to any one of Aspects 1 to 14.

[0225] Aspect 16: An apparatus for wireless communication at a UE, the apparatus comprises at least one component for performing the method according to any one of Aspects 1 to 14.

[0226] Aspect 17: A non - transitory computer - readable medium storing 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 14. It should be noted that the methods described herein describe possible specific implementations, and the operations and steps can be rearranged or otherwise modified and other specific implementations are possible. Additionally, aspects from two or more methods can be combined.

[0227] Although aspects of LTE, LTE-A, LTE-A Pro, or NR systems may be described for example purposes and the terms LTE, LTE-A, LTE-A Pro, or NR 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 described techniques 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.

[0228] The information and signals described herein may be represented using any of a variety of different technologies and methods. For example, data, instructions, commands, information, signals, bits, symbols, and chips referred to 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.

[0229] The various illustrative blocks and components described in connection with the disclosure herein may be implemented or performed using a general-purpose processor, DSP, ASIC, CPU, FPGA, or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. The general-purpose processor may be a microprocessor, but in the 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).

[0230] The functions described herein may be implemented using hardware, software executed by a processor, firmware, or any combination thereof. When implemented in software executed by a processor, the functions may be stored as one or more instructions or codes on a computer-readable medium or transmitted using one or more instructions or codes on a computer-readable medium. Other examples and implementations are within the scope of the present 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, hardwiring, or any combination of these items. The features implementing the functions may also be physically located at different positions, including being distributed such that portions of the functions are implemented at different physical locations.

[0231] A computer-readable medium includes both a non-transitory computer storage medium and a communication medium including any medium that facilitates transfer of a computer program from one location to another. A non-transitory storage medium may be any available medium that can be accessed by a general purpose or special purpose computer. By way of example, and not limitation, non-transitory computer-readable media can include RAM, ROM, electrically erasable programmable ROM (EEPROM), flash memory, compact disc read only memory (CD-ROM) or other optical disc storage, magnetic disk storage or other magnetic storage devices, or any other non-transitory medium that can be used to carry or store desired program code means in the form of instructions or data structures and that can be accessed by a general purpose or special purpose computer or a general purpose or special purpose processor. Also, any connection is properly termed a computer-readable medium. For example, if software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of computer-readable medium. As used herein, disk and disc include CD, laser disc, optical disc, digital versatile disc (DVD), floppy disk, and Blu-ray disc. Disk may reproduce data magnetically, while disc may reproduce data optically using lasers. Combinations of the above are also included within the scope of computer-readable medium.

[0232] As used herein, including in the claims, the "or" used in a list of items (e.g., a list of items that is accompanied by a phrase such as "at least one of" or "one or more of") indicates an inclusive listing such that, for example, a listing of at least one of A, B, or C means A or B or C or AB or AC or BC or ABC (i.e., A and B and C). Additionally, as used herein, the phrase "based on" should not be construed as a reference to a closed set of conditions. For example, an example step described as "based on condition A" may 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 "at least partially based on".

[0233] The term "determine" or "determining" encompasses a variety of actions and, accordingly, "determine" can include operations such as calculating, computing, processing, deriving, investigating, looking up (such as looking up in a table, database, or other data structure), ascertaining, and the like. Additionally, "determine" can include receiving (e.g., receiving information), accessing (e.g., accessing data stored in a memory), etc. Further, "determine" can include parsing, obtaining, selecting, choosing, establishing, and other such like actions.

[0234] In the drawings, similar components or features may have the same reference numerals. Additionally, various components of the same type can be distinguished by adding a dash and a second numeral used to differentiate between similar components after the reference numeral. If only the first reference numeral is used in the specification, the description can apply to any one of the similar components having the same first reference numeral, regardless of the second reference numeral or any other subsequent reference numerals.

[0235] The description set forth herein in connection with the drawings describes exemplary configurations and does not represent all examples that can be implemented or that are within the scope of the claims. The term "exemplary" as used herein means "serving as an example, instance, or illustration" and not "preferred" or "advantageous over other examples". The detailed description includes specific details for providing an understanding of the described techniques. However, the techniques can be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form to avoid obscuring the concepts of the described examples.

[0236] The present description is provided to enable a person of ordinary skill in the art to make or use the present disclosure. Various modifications to the present disclosure will be readily apparent to those of ordinary skill in the art, and the general principles defined herein can 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 is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for wireless communication at a user equipment (UE), the method comprises: receiving a downlink message via a downlink channel, the downlink message including an indication of a pre - decoder applied to one or more downlink signals; receiving the one or more downlink signals using at least one demodulation reference signal and the pre - decoder, wherein the one or more downlink signals are at least partially mismatched in gain and phase; performing an iterative channel estimation process to estimate the downlink channel; performing a gain and phase mismatch equalization process at the UE to equalize the estimated gain and phase mismatch of the one or more downlink signals based at least in part on the estimated downlink channel and the pre - decoder; and receiving one or more equalized downlink signals according to the gain and phase mismatch equalization process.

2. The method according to claim 1, the method further comprises: performing the iterative channel estimation process to estimate a physical channel associated with the one or more downlink signals using the at least one demodulation reference signal; and estimating the estimated gain and phase mismatch based at least in part on the estimated physical channel, the pre - decoder, or both.

3. The method according to claim 1, wherein the indication of the pre - decoder includes one or more pre - decoder coefficients, and receiving the one or more downlink signals further comprises: applying the one or more pre - decoder coefficients to the one or more downlink signals.

4. The method according to claim 1, wherein performing the iterative channel estimation process further comprises: performing a first channel estimation process; performing the gain and phase mismatch equalization process; and performing at least a second channel estimation process based at least in part on the estimated gain and phase mismatch.

5. The method according to claim 1, wherein performing the gain and phase mismatch equalization process further comprises: eliminating at least a part of the estimated gain and phase mismatch.

6. The method according to claim 1, wherein receiving the downlink message including the indication of the pre - decoder further comprises: receiving the indication of the pre - decoder via a set of downlink pre - coded data, wherein the one or more pre - decoder coefficients are determined based at least in part on the set of downlink pre - coded data.

7. The method according to claim 1, the method further comprises: performing the gain and phase mismatch equalization process and simultaneously equalizing the estimated gain and phase mismatch of the one or more downlink signals.

8. The method according to claim 1, wherein receiving the one or more downlink signals further comprises: reproducing the one or more downlink signals based at least in part on the at least one demodulation reference signal and the pre - decoder for the gain and phase mismatch equalization process.

9. The method according to claim 1, wherein receiving the indication of the pre - decoder further comprises: receiving an indication of the duration for which the pre - decoder is applied to the one or more downlink signals, the time slot number, or both.

10. The method according to claim 1, wherein the value of the pre - decoder comprises a static value or a pseudo - random value, and the method further comprises: Performing the gain and phase mismatch equalization process at least in part based on the value of the pre - decoder.

11. The method according to claim 1, wherein the indication of the pre - decoder comprises a first indication of a first pre - decoder, and the method further comprises: Receiving, via the first indication of the first pre - decoder, a second indication of a second pre - decoder to be applied to the one or more downlink signals after a threshold duration; and Performing the gain and phase mismatch equalization process according to the second pre - decoder.

12. The method according to claim 1, the method further comprises: Receiving a periodic indication from a network entity, the periodic indication indicating the periodicity for the UE to perform the gain and phase mismatch equalization process at least in part based on one or more operating factors of the network entity.

13. The method according to claim 1, wherein the gain and phase mismatch equalization process comprises an in - phase quadrature phase mismatch equalization process.

14. The method according to claim 1, wherein the estimated gain and phase mismatch is a frequency - dependent gain and phase mismatch.

15. An apparatus for wireless communication at a user equipment (UE), the apparatus comprises: A processor; A memory coupled to the processor; and Instructions stored in the memory and executable by the processor to cause the apparatus to: Receive, via a downlink channel, a downlink message comprising an indication of a pre - decoder applied to one or more downlink signals; Receive the one or more downlink signals using at least one demodulation reference signal and the pre - decoder, wherein the one or more downlink signals are at least partially mismatched in gain and phase; Perform an iterative channel estimation process to estimate the downlink channel; Perform a gain and phase mismatch equalization process at the UE to equalize the estimated gain and phase mismatch of the one or more downlink signals at least in part based on the estimated downlink channel and the pre - decoder; and Receive one or more equalized downlink signals according to the gain and phase mismatch equalization process.

16. The apparatus according to claim 15, wherein the instructions are further executable by the processor to cause the apparatus to: Perform the iterative channel estimation process to estimate a physical channel associated with the one or more downlink signals using the at least one demodulation reference signal; and Estimate the estimated gain and phase mismatch at least in part based on the estimated physical channel, the pre - decoder, or both.

17. The apparatus according to claim 15, wherein the indication of the pre - decoder comprises one or more pre - decoder coefficients, and the instructions for receiving the one or more downlink signals are further executable by the processor to cause the apparatus to: Apply the one or more pre - decoder coefficients to the one or more downlink signals.

18. The apparatus according to claim 15, wherein the instructions for performing the iterative channel estimation process can be further executed by the processor to cause the apparatus to: perform a first channel estimation process; perform the gain and phase mismatch equalization process; and perform at least a second channel estimation process at least in part based on the estimated gain and phase mismatch.

19. The apparatus according to claim 15, wherein the instructions for performing the gain and phase mismatch equalization process can be further executed by the processor to cause the apparatus to: eliminate at least a portion of the estimated gain and phase mismatch.

20. The apparatus according to claim 15, wherein the instructions for receiving the downlink message including the indication of the pre - decoder can be further executed by the processor to cause the apparatus to: receive the indication of the pre - decoder via a set of downlink precoded data, wherein the one or more pre - decoder coefficients are determined at least in part based on the set of downlink precoded data.

21. The apparatus according to claim 15, wherein the instructions can be further executed by the processor to cause the apparatus to: perform the gain and phase mismatch equalization process and, simultaneously, equalize the estimated gain and phase mismatch of the one or more downlink signals.

22. The apparatus according to claim 15, wherein the instructions for receiving the one or more downlink signals can be further executed by the processor to cause the apparatus to: re - generate the one or more downlink signals at least in part based on the at least one demodulation reference signal and the pre - decoder for the gain and phase mismatch equalization process.

23. The apparatus according to claim 15, wherein the instructions for receiving the indication of the pre - decoder can be further executed by the processor to cause the apparatus to: receive an indication of the duration, time - slot number, or both, for which the pre - decoder is applied to the one or more downlink signals.

24. The apparatus according to claim 15, wherein the value of the pre - decoder includes a static value or a pseudo - random value, and the instructions can be further executed by the processor to cause the apparatus to: perform the gain and phase mismatch equalization process at least in part based on the value of the pre - decoder.

25. The apparatus according to claim 15, wherein the indication of the pre - decoder includes a first indication of a first pre - decoder, and the instructions can be further executed by the processor to cause the apparatus to: receive a second indication of a second pre - decoder to be applied to the one or more downlink signals after a threshold duration via the first indication of the first pre - decoder; and perform the gain and phase mismatch equalization process according to the second pre - decoder.

26. The apparatus according to claim 15, wherein the instructions can be further executed by the processor to cause the apparatus to: Receive a periodic indication from a network entity, the periodic indication indicating the periodicity for the UE to perform the gain and phase mismatch equalization process based at least in part on one or more operating factors of the network entity.

27. The apparatus according to claim 15, wherein the gain and phase mismatch equalization process includes an in-phase quadrature phase mismatch equalization process.

28. The apparatus according to claim 15, wherein the estimated gain and phase mismatch are frequency-dependent gain and phase mismatches.

29. An apparatus for wireless communication at a user equipment (UE), the apparatus comprising: means for receiving a downlink message via a downlink channel, the downlink message including an indication of a pre-coder applied to one or more downlink signals; means for receiving the one or more downlink signals using at least one demodulation reference signal and the pre-coder, wherein the one or more downlink signals are at least partially mismatched in gain and phase; means for performing an iterative channel estimation process to estimate the downlink channel; means for performing a gain and phase mismatch equalization process at the UE to equalize the estimated gain and phase mismatch of the one or more downlink signals based at least in part on the estimated downlink channel and the pre-coder; and means for receiving one or more equalized downlink signals according to the gain and phase mismatch equalization process.

30. A non-transitory computer-readable medium storing code for wireless communication at a user equipment (UE), the code including instructions executable by a processor to: receive a downlink message via a downlink channel, the downlink message including an indication of a pre-coder applied to one or more downlink signals; receive the one or more downlink signals using at least one demodulation reference signal and the pre-coder, wherein the one or more downlink signals are at least partially mismatched in phase; perform an iterative channel estimation process to estimate the downlink channel; perform a gain and phase mismatch equalization process at the UE to equalize the estimated gain and phase mismatch of the one or more downlink signals based at least in part on the estimated downlink channel and the pre-coder; and receive one or more equalized downlink signals according to the gain and phase mismatch equalization process.

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