Patent Application
20230155299
This disclosure relates to wireless communications and in particular to a method and system for antenna array grouping.
In wireless communication systems today, groups of antennas are used to increase the effective antenna aperture of a radio used in wireless communications. Such communication systems include New Radio (NR) (also known as 5G) and Long Term Evolution (LTE) (also known as 4G). Increasing the effective aperture increases the antenna directivity. Increasing antenna directivity helps to overcome isotropic free space path loss. The receive (RX) and transmit (TX) functionality is usually orthogonalized using either the time domain (time division duplex, TDD), or the frequency domain (frequency division duplex, FDD). In both cases, the momentary spectrum efficiency is halved compared to using shared time and frequency resources for both reception and transmission. Such a system is usually referred to as an on-frequency, full-duplex system. Such systems present self-interference. This is the case because a transmitter will leak unwanted signal power into a nearby receiver. This leakage can be significantly stronger than the wanted receive signal power level, and thus, the leakage degrades the receiver sensitivity by several orders of magnitude.
On-frequency, full-duplex systems make use of several techniques that when combined, achieve substantial suppression of the unwanted, self-induced, transmit interferer in the receiver. In practice, three approaches may be exercised in parallel. These include: 1) antenna port isolation in terms of physically separating antennas and/or using separate polarizations, and/or using isolator/circulator functionality for cases where the antenna is shared for transmission and reception; 2) analog cancelation loops from the transmitter to the receiver in order to suppress the unwanted interferer to a level where receiver nonlinearity does not degrade performance beyond what is acceptable; and 3) cancellation in the digital baseband where remaining transmit leakage can be cancelled, and where modeled transmit nonlinearities can be taken into account. Depending on system requirements, one or possibly two of the aforementioned techniques may be omitted, but for high performing cellular systems, usually demanding upwards of 100 dB of total transmit interferer suppression, all three approaches are typically fully exploited.
An antenna array includes multiple antenna elements, each with its own feed. By adjusting the phase between elements (or sub-arrays), an antenna array can be steered electronically, without having to physically move the antenna system. For multiple input multiple output (MIMO) systems using group antennas, one inherent problem is that multiple transmitters will simultaneously induce self-interference in each receiver. Thus, the complexity of self-cancellation grows. For large antenna arrays having multiple transceiver (receiver and transmitter) integrated circuits (ICs), (also referred to as “tiles”) to drive the antenna ports, additional problems occur as analog cancellation paths between transmitters and receivers might call for analog inter-chip signaling, including radio frequency (RF) signaling. This, in turn, may complicate manufacture of the array beyond what is feasible. Such systems might need to rely only on antenna isolation techniques and digital cancellation. As a result, completely separated antenna panels (RX and TX) may be used. This has three potentially negative side effects when driven by individual radio ICs: 1) a large distance between antenna panels makes the total footprint large; 2) using a common transceiver IC for cost reasons means that either TX or RX will not be used so that unused chip area is expected; and 3) using separate transceiver ICs drives research and development, validation, and production cost as two ICs must be developed, and their respective volume is half the total volume. Circulators can only remove leakage from a transmitter to a receiver connected to the same circulator. Leakage from a nearby antenna cannot be distinguished from the wanted signal to be received by the antenna.
Some embodiments advantageously provide a method and system for antenna array grouping to address the problems described above. In some embodiments, antenna elements in a group of antenna elements are arranged to reduce self-interference leakage. In some embodiments, TX and RX circuits are interleaved in the group antenna to avoid the above-described interference, while preserving good isolation between TX and RX antenna elements when operated in on-frequency full-duplex mode. In some embodiments, the antenna elements are arranged such that the nearest interfering TX antenna elements are connected to the same radio IC as the victim RX antenna elements in order to enable on-chip analog cancelation techniques. This is accomplished while using the same radio IC, i.e., tile, for all sub-arrays across the panel, but the geometry is alternated in order to effectively create more TX to RX isolation when antenna elements are connected to different radio ICs.
In some embodiments, a transmit and receive antenna array panel are interleaved into a joint antenna array structure where the physical interleaving is shaped to enable on-chip analog self-interference cancellation methods for the most significant TX aggressors. In an on-frequency full-duplex use case, this enables additional suppression without sacrificing total antenna area or antenna directivity. The same radio ICs can be used across the interleaved TX/RX antenna panel, thereby achieving a significant cost advantage in terms of research and development, validation, and chip manufacturing volume.
Advantages of configurations disclosed herein include greater receiver sensitivity, lower interference at receivers caused by transmissions from nearby transmitters (which are now further away), ease of design and manufacture, as well as scalability.
According to one aspect, a communication apparatus to mitigate transmit to receive leakage in on-frequency full-duplex systems having a plurality of antenna elements is provided. The communication apparatus includes a panel having transceiver integrated circuits, ICs, the panel including a plurality of transceiver integrated circuits, ICs, each transceiver IC having a row of transmit circuits and a row of receive circuits, the transceiver ICs being arranged so that a row of receive circuits on one transceiver IC is adjacent to a row of receive circuits on an adjacent transceiver IC.
According to this aspect, in some embodiments, the communication apparatus further comprises a plurality of panels, the plurality of panels being arranged side by side so that a row of receive circuits on a transceiver IC on a first panel is aligned with a row of receive circuits on a transceiver IC on a second panel. In some embodiments, a plurality of transceiver ICs on the panel are arranged by rotating every other transceiver IC so that rows of receive circuits on one panel are in a same row as a row of receive circuits on an adjacent panel. In some embodiments, the rotation is approximately 180 degrees. In some embodiments, the plurality of panels are arranged side by side so that a row of receive circuits on a transceiver IC on a first panel is aligned with a row of receive circuits of a transceiver IC on a second panel. In some embodiments, a distance between adjacent panels is less than a wavelength at a frequency of operation of the plurality of antenna elements.
According to yet another aspect, a method for arranging transceiver integrated circuits, ICs, to mitigate transmit to receive leakage in on-frequency full-duplex systems having a plurality of antenna elements is provided. The method includes arranging a row of transmit circuits and a row of receive circuits on a transceiver IC; and arranging a plurality of transceiver ICs on a first panel so that a row of receive circuits on one transceiver IC is adjacent to a row of receive circuits on an adjacent transceiver IC.
According to this aspect, in some embodiments, the method further includes arranging a plurality of panels side by side so that a row of receive circuits on a transceiver IC on the first panel is aligned with a row of receive circuits on a transceiver IC on a second panel. In some embodiments, the method further includes arranging a plurality of panels and arranging the plurality of transceiver ICs on the first panel by rotating every other transceiver IC so that rows of receive circuits on the first panel are in a same row as a row of receive circuits on an adjacent panel of the plurality of panels. In some embodiments, the rotation is approximately 180 degrees. In some embodiments, the method further includes arranging the plurality of panels side by side so that a row of receive circuits on a transceiver IC on a first panel is aligned with a row of receive circuits of a transceiver IC on a second panel. In some embodiments, a distance between adjacent panels is less than a wavelength at a frequency of operation of the plurality of antenna elements.
According to another aspect, an array of transceiver integrated circuits, ICs, is configured to be in communication with an array of antenna elements, each transceiver IC having a row of receive circuits and a row of transmit circuits, transceiver ICs in the array of transceiver ICs being arranged so that a row of receive circuits on one transceiver IC is adjacent to a row of receive circuits on an adjacent transceiver IC.
According to this aspect, in some embodiments, two adjacent transceiver ICs are arranged so that a row of receive circuits on one transceiver IC are more distant to a row of transmit circuits on the other adjacent transceiver IC than to a row of receive circuits on the other adjacent transceiver IC. In some embodiments, transceiver ICs are arranged in panels so that a row of receive circuits on one panel is in a same row as a row of receive circuits on an adjacent panel. In some embodiments, a distance between adjacent transceiver ICs is less than a wavelength at a frequency of operation of at least one antenna in communication with one of the adjacent transceiver ICs. In some embodiments, a first transceiver IC is rotated 180 degrees with respect to an orientation of a second transceiver IC adjacent to the first transceiver IC.
According to yet another aspect, a panel of transceiver integrated circuits, ICs is configured such that each transceiver IC has a row of transmit circuits and a row of receive circuits, every other transceiver IC in a plurality of rows of transceiver IC on the panel being rotated with respect to an adjacent transceiver IC on the panel.
According to this aspect, in some embodiments, any two adjacent transceiver ICs on the panel are arranged so that a row of receive circuits on one IC are more distant to a row of transmit circuits on the other adjacent transceiver IC than to a row of receive circuits on the other adjacent transceiver IC.
According to another aspect, a method of manufacturing a panel of transceiver integrated circuits, ICs, for electrical communication with a plurality of antenna elements is provided. The method includes placing a first transceiver IC on a printed circuit board; and placing a second transceiver IC on the printed circuit board so that a first row of receive circuits on the first transceiver IC is adjacent to a second row of receive circuits on the second transceiver IC.
According to this aspect, in some embodiments, the second transceiver IC is placed such that the second transceiver IC is rotated with respect to an orientation of the first transceiver IC. In some embodiments, the second transceiver IC is rotated by an angle in the range of 178 to 182 degrees. In some embodiments, the second transceiver IC is rotated by an angle in the range of 170 to 190 degrees. In some embodiments, the second transceiver IC is rotated by 180 degrees. In some embodiments, a distance between the first and second transceiver ICs are positioned to be less than a wavelength apart at a frequency of operation of the plurality of antenna elements.
A more complete understanding of embodiments described herein, and the attendant advantages and features thereof, will be more readily understood by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein:
Before describing in detail example embodiments, it is noted that the embodiments reside primarily in combinations of apparatus components and processing steps related to antenna array grouping. Accordingly, the system and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present disclosure so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.
As used herein, relational terms, such as “first” and “second,” “top” and “bottom,” and the like, may be used solely to distinguish one entity or element from another entity or element without necessarily requiring or implying any physical or logical relationship or order between such entities or elements. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the concepts described herein. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes” and/or “including” when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
In embodiments described herein, the joining term, “in communication with” and the like, may be used to indicate electrical or data communication, which may be accomplished by physical contact, induction, electromagnetic radiation, radio signaling, infrared signaling or optical signaling, for example. One having ordinary skill in the art will appreciate that multiple components may interoperate and modifications and variations are possible of achieving the electrical and data communication.
It is also noted that the terms “IC” and “IC chip” are used interchangeably herein.
Referring to the drawing figures, where like reference designators refer to like elements,
In order to make use of a single transceiver IC, (also referred to as a tile), in accordance with the disclosure herein, the two antenna panels can be merged into one structure as shown in
Some embodiments are as shown in
Advantages of configurations disclosed herein include greater receiver sensitivity, lower interference at receivers caused by transmissions from nearby transmitters (which are now further away), ease of design and manufacture, as well as scalability, as compared with other arrangements.
Aggressor power may increase by roughly 3 dB, whereas the pathloss increases by 6 dB and as it rolls off inversely proportional to the squared distance. Thus, a reduction of 3 dB compared to the original interleaving layout of
When antenna panels are combined to form larger array structures, e.g., to increase the antenna directivity, the interference reduction effects are still present. An example is illustrated in
As is known, printed circuit boards are made of a dielectric material with a copper conductor layer on one or both sides. The dielectric may incorporate glass, ceramic, or other filler for improved electrical and mechanical stability. Antennas can be formed on one or both sides of the laminate or by using multiple layers of laminate materials. When more than one side is used, conductive layers are may be electrically connected by plated through holes (PTHs) in the insulator layer.
The antenna layout obtained by rotating every other radio IC (or its antennas) generates a different antenna pattern compared to an evenly spaced antenna element layout. When alternating between RX and TX for every other row, as in
In operation, it is contemplated that the antenna layout described here can, as a non-limiting example, be used in a cellular wireless communication system such as a wireless communication system compliant with a 3rd Generation Partnership Project (3GPP) set of standards. Such standards may include, but are not limited to Long Term Evolution (LTE) and New Radio (NR) (also known as 5G). It is further contemplated that the layout of TRX ICs described herein can be used in connection with a 3GPP network node, e.g., a base station, such as a gNB, eNB, etc. Such base stations have communication equipment that enable wireless communications with a plurality of wireless devices. Such communications are over the air on an RF channel via antennas. Antennas of the communications equipment may be connected to the transceiver ICs described herein. However, implementations are not limited to 3GPP-based networks. Further, additional components in the transmission and receive paths, e.g., power amplifiers, filters, etc., are not shown for ease of understanding.
Thus, in some embodiments, a method to group antenna array elements to mitigate Tx-to-Rx leakage in on-frequency full-duplex systems is provided. In some embodiments, the Rx and Tx antennas with strongest unwanted coupling are all fed by the same transceiver (TRX) IC and analog cancellation methods can easily be applied to compensate the unwanted leakage. Receive (Rx) and transmit (Tx) antenna elements fed by different TRX ICs are moved further apart from each other in some embodiments, and will therefore have increased isolation and no need for analog cancellation loops between transceiver ICs.
Note that the configurations disclosed herein for orienting adjacent TRX ICs 24, 25, 26, 27 may produce different beam patterns than the beam patterns of conventionally oriented transceiver ICs. This is because the spacing between rows of transmit circuits 28, 34 is non-uniform in the configurations disclosed herein, whereas the spacing between rows of transmit circuits is uniform. However, the total array size in both cases are similar so that the respective directivity is reduced by −3 dB in relation to the maximum aperture given the panel size, i.e., when connecting all elements to either RX or TX. The beam steering control (i.e. time delay, or phase shift, between antenna element) will have to be different for the two layouts, but in principle the same main lobe performance can be achieved.
As mentioned, because there is non-uniform spacing of the transmit circuits, a different beam pattern may result as compared to the beam pattern generated with uniform spacing. In particular, exaggerated sidelobes may result, especially for large steering angles. For small steering angles, there can be expected only insignificant differences between beams resulting from non-uniform spacing and from uniform spacing. Also, there may be a variation between an azimuth cut of the beam and an elevation cut of the beam. For example, for the geometry of
Because of non-uniform spacing, when a beam is steered away from boresight for example, between −10 and −30 degrees, reduction in beam gain may increase by as much as 2-3 dB. This reduction in gain may be offset by the reduction in path loss resulting from shorter distance between the base station and the wireless device(s) to which the beam is steered. For wireless devices on a cell boarder, maximum gain may compensate for the increased path loss between the based station and the wireless devices on the cell boarder. Note that the configurations disclosed herein may eliminate a need for analog cancellation loops between transceiver ICs.
According to one aspect, a communication apparatus to mitigate transmit to receive leakage in on-frequency full-duplex systems having a plurality of antenna elements is provided. The communication apparatus includes a panel 42 having transceiver integrated circuits, ICs 24 and 26. The panel 42 includes a plurality of transceiver integrated circuits, ICs 24 and 26, each transceiver IC 24, 26 having a row of transmit circuits 28, 34 and a row of receive circuits 30, 32, the transceiver ICs 24 and 26 being arranged so that a row of receive circuits 30 on one transceiver IC 24 is adjacent to a row of receive circuits 32 on an adjacent transceiver IC 26.
According to this aspect, in some embodiments, the communication apparatus further comprising a plurality of panels 42, 44, the plurality of panels 42, 44 being arranged side by side so that a row of receive circuits 30 on a transceiver IC 24 on a first panel 42 is aligned with a row of receive circuits 30 on a transceiver IC 25 on a second panel 44. In some embodiments, a plurality of transceiver ICs 24, 26 on the panel 42 are arranged by rotating every other transceiver IC 24, 26 so that rows of receive circuits 30 on one panel 42 are in a same row as a row of receive circuits 30 on an adjacent panel 44. In some embodiments, the rotation is approximately 180 degrees. In some embodiments, a distance between adjacent transceiver ICs 24, 26 is less than a wavelength at a frequency of operation of the plurality of antenna elements. In some embodiments, the plurality of panels 42, 44 are arranged side by side so that a row of receive circuits 30 on a transceiver IC 24 on a first panel 42 is aligned with a row of receive circuits 30 of a transceiver IC 25 on a second panel 44. In some embodiments, a distance between adjacent panels 42 and 44 is less than a wavelength at a frequency of operation of the plurality of antenna elements.
According to yet another aspect, a method for arranging transceiver integrated circuits, ICs, 24, 26 to mitigate transmit to receive leakage in on-frequency full-duplex systems having a plurality of antenna elements is provided. The method includes arranging a row of transmit circuits 28 and a row of receive circuits 30 on a transceiver IC 24; and arranging a plurality of transceiver ICs 24, 26 on a first panel 42 so that a row of receive circuits 30 on one transceiver IC 24 is adjacent to a row of receive circuits 32 on an adjacent transceiver IC 26.
According to this aspect, in some embodiments, the method further includes arranging a plurality of panels 42, 44 side by side so that a row of receive circuits 30 on a transceiver IC 24 on the first panel 42 is aligned with a row of receive circuits 30 on a transceiver IC 25 on a second panel 44. In some embodiments, the method further includes arranging a plurality of panels 42, 44 and arranging the plurality of transceiver ICs 24, 26 on the first panel 42 by rotating every other transceiver IC 24 so that rows of receive circuits 30 on the first panel 42 are in a same row as a row of receive circuits 30 on an adjacent panel 44 of the plurality of panels. In some embodiments, the rotation is approximately 180 degrees. In some embodiments, the method further includes arranging the plurality of panels 42, 44 side by side so that a row of receive circuits 30 on a transceiver IC 24 on a first panel 42 is aligned with a row of receive circuits of a transceiver IC 25 on a second panel 44. In some embodiments, a distance between adjacent panels 42, 44 is less than a wavelength at a frequency of operation of the plurality of antenna elements.
According to another aspect, an array of transceiver integrated circuits, ICs, 24, 26 is configured to be in communication with an array of antenna elements, each transceiver IC 24, 26 having a row of receive circuits 30 and a row of transmit circuits 28, transceiver ICs 24, 26 in the array of transceiver ICs 24, 26 being arranged so that a row of receive circuits 30 on one transceiver IC 24 is adjacent to a row of receive circuits 30 on an adjacent transceiver IC 26.
According to this aspect, in some embodiments, two adjacent transceiver ICs 24, 26 are arranged so that a row of receive circuits 30 on one transceiver IC 24 are more distant to a row of transmit circuits 34 on the other adjacent transceiver IC 26 than to a row of receive circuits on the other adjacent transceiver IC 26. In some embodiments, transceiver ICs 24, 25 are arranged in panels 42, 44 so that a row of receive circuits 30 on one panel 42 is in a same row as a row of receive circuits 30 on an adjacent panel 44. In some embodiments, a distance between adjacent transceiver ICs 24 and 26 is less than a wavelength at a frequency of operation of at least one antenna in communication with one of the adjacent transceiver ICs 24, 26. In some embodiments, a first transceiver IC 24 is rotated with respect to an orientation of a second transceiver IC 26 adjacent to the first transceiver IC 24.
According to yet another aspect, a panel 42 of transceiver integrated circuits, ICs 24 is configured such that each transceiver IC 24 has a row of transmit circuits 28 and a row of receive circuits 30, every other transceiver IC 24 in a plurality of rows of transceiver ICs on the panel 42 being rotated with respect to an adjacent transceiver IC 26 on the panel.
According to this aspect, in some embodiments, any two adjacent transceiver ICs 24, 26 on the panel 42 are arranged so that a row of receive circuits 30 on one transceiver IC 24 are more distant to a row of transmit circuits 34 on the other adjacent transceiver IC 26 than to a row of receive circuits 32 on the other adjacent transceiver IC 26.
According to another aspect, a method of manufacturing a panel of transceiver integrated circuits, ICs, 24 for communication with a plurality of antenna elements is provided. The method includes placing a first transceiver IC 24 on a printed circuit board; and placing a second transceiver IC 26 on the printed circuit board so that a first row of receive circuits on the first transceiver IC 24 is adjacent to a second row of receive circuits on the second transceiver IC 26.
According to this aspect, in some embodiments, the second transceiver IC 26 is placed such that the second transceiver IC 26 is rotated with respect to an orientation of the first transceiver IC 24. In some embodiments, the second transceiver IC 26 is rotated by an angle in the range of 178 to 182 degrees. In some embodiments, the second transceiver IC 26 is rotated by an angle in the range of 170 to 190 degrees. In some embodiments, the second transceiver IC 26 is rotated by 180 degrees. In some embodiments, a distance between the first and second transceiver ICs 24, 26 are positioned to be less than a wavelength apart at a frequency of operation of the plurality of antenna elements.
According to one aspect, a method for grouping antenna elements to mitigate transmit to receive leakage in on-frequency full-duplex systems is provided. The method includes arranging a row of transmit integrated circuits, ICs, 28 and a row of receive circuits 30 on an IC chip 24. The method also includes arranging a plurality of IC chips 24 on a panel 42 so that a row of receive circuits 30 on one IC chip 24 is adjacent to a row of receive circuits 32 on an adjacent IC chip 26.
According to this aspect, in some embodiments, the method further includes, arranging a plurality of panels 42, 44 side by side. In some embodiments, a distance between adjacent IC chips 24, 26 is less than a wavelength at a frequency of operation of the group of antenna elements and a distance between adjacent panels 42, 44 is less than the wavelength. In some embodiments, the IC chips 24, 26 may be much smaller than the area of the antenna panel 42, 44 the IC chips are connected to. In such cases, it is contemplated that the IC chips 24, 26 may be separated by more than a wavelength at a frequency of operation.
According to another aspect, an array of transmit/receive integrated circuits, ICs, chips 24, 25, 26, 27 are arranged to feed a group of antennas. Each IC chip has a row of receive circuits 30, 32 and a row of transmit circuits 28, 34. IC chips in the array are arranged so that a row of receive circuits 30 on one IC chip 24 is adjacent to a row of receive circuits 32 on an adjacent IC chip 26.
According to this aspect, in some embodiments, the IC chips are arranged in panels 42, 44 spaced less than a wavelength apart at a frequency of operation of the group of antennas. In some embodiments, the rows of receive circuits 30 in one panel 42 are in a same row as a row of receive circuits 30 in an adjacent panel 44.
Some embodiments include:
Embodiment A1. A method for grouping antenna elements to mitigate transmit to receive leakage in on-frequency full-duplex systems, the method comprising:
arranging a row of transmit integrated circuits, ICs, and a row of receive ICs on an IC chip; and
arranging a plurality of IC chips on a panel so that a row of receive circuits on one IC chip is adjacent to a row of receive circuits on an adjacent IC chip.
Embodiment A2. The method of Embodiment A1, further comprising arranging a plurality of panels side by side.
Embodiment A3. The method of Embodiment A2, wherein a distance between adjacent IC chips is less than a wavelength at a frequency of operation of the group of antenna elements and a distance between adjacent panels is less than the wavelength.
Embodiment B1. An array of transmit/receive integrated circuit, IC, chips arranged to feed a group of antennas, each IC chip having a row of receive circuits and a row of transmit circuits, IC chips in the array being arranged so that a row of receive circuits on one IC chip is adjacent to a row of receive circuits on an adjacent IC chip.
Embodiment B2. The array of Embodiment B1, wherein the IC chips are arranged in panels spaced less than a wavelength apart at a frequency of operation of the group of antennas.
Embodiment B3. The array of Embodiment B2, wherein the rows of receive circuits in one panel are in a same row as a row of receive circuits in an adjacent panel.
IC Integrated circuit
RX Receive/receiver
TX Transmit/transmitter
TRX Transceiver
It will be appreciated by persons skilled in the art that the present embodiments are not limited to what has been particularly shown and described herein above. In addition, unless mention was made above to the contrary, it should be noted that all of the accompanying drawings are not to scale. A variety of modifications and variations are possible in light of the above teachings without departing from the scope of the following claims.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2020/075677 | 9/15/2020 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 63004224 | Apr 2020 | US |
