Patent Application
20240014577
In-band full-duplex (IBFD) systems operate in full-duplex mode, where a signal is transmitted and received on the same frequency at the same time. This scheme is challenging to implement because an effective system requires a high amount of isolation between a co-located transmitter and receiver in order to avoid self-interference (SI). Minimizing the amount of transmit signal power coupled to the receiver helps to avoid saturating the receiver and thus allows the reception of weak signals from remote users. IBFD systems typically minimize SI by using multiple layers of cancellation, the first of which is the antenna.
Furthermore, while conventional IBFD antennas may effectively suppress SI, they do not provide any insight into a direction from which the signals are received. For such a capability, IBFD directional phased arrays have been investigated, but IBFD directional phased arrays are expensive, complex to manufacture and complex to operate.
This Summary introduces a selection of concepts in simplified form that are described further below in the Detailed Description. This Summary neither identifies key or essential features, nor limits the scope, of the claimed subject matter.
Described is an in-band full-duplex (IBFD) array antenna. IBFD antennas provided in accordance with the concepts described herein provide both omnidirectional radiation-pattern coverage and direction-of-arrival (DoA) estimation of the received signals (i.e., IBFD antennas provided in accordance with the concepts described herein have a direction finding (DF) capability). Thus, IBFD antennas provided in accordance with the concepts described herein integrate a unique receive beamforming functionality which can be used to provide information indicative of a direction from which signals are received. Such DF information can be used to improve communications links. Accordingly, IBFD antennas provided in accordance with the concepts described herein find use in wireless communications and other applications.
Omnidirectional phasing is achieved using circular modes and a plurality of appropriately configured and fed wideband horn antennas are configured to provide a plurality of difference antenna beams.
Furthermore, IBFD antennas implemented in accordance with the concepts described herein provide a mechanism to access frequency spectrums more efficiently as well as host multiple functions (e.g., transmit functions, receive functions and direction-finding functions) at the same time.
IBFD techniques enable wireless systems to simultaneously utilize the same frequency band for transmit and receive operation. Using the same frequency band for transmit and receive operations can help propel the adoption of V2X systems by allowing platforms to not only connect to multiple networks concurrently, but also to do so while reducing (and ideally, minimizing) use of a frequency spectrum (i.e., by using the same frequency band for transmit and receive operations, spectral utilization is minimized). This may be accomplished using antenna designs, including those for vehicles, which combat self-interference (SI) resulting from the use of the same frequency band for transmit and receive operations and also provide direction finding capability.
In accordance with one aspect of the concepts disclosed herein, described is an in-band full-duplex (IBFD) antenna comprising a means to provide an omnidirectional radiation pattern around a moving platform, wherein the moving platform is attached to a vehicle; and a means to perform adaptive beam forming in a receive mode of operation.
In one embodiment, an IBFD antenna comprises a single omnidirectional transmit monopole antenna element for use in a transmit mode of operation and a plurality of horn antenna elements configured for use in a receive mode of operation. In embodiments, the plurality of horn antenna elements are provided as wide-angle short horn antenna elements.
In embodiments, the plurality of horn antenna elements are disposed in a first plane and the monopole antenna element is disposed in a second, different plane.
In embodiments, eight wide-angle short horns comprise two sets of four probe-fed wide-angle short horns. In one embodiment, a first set of four probe-fed wide-angle short horns are disposed above a second set of four probe-fed wide-angle short horns. Each set of four probe-fed wide-angle short horns generate a total of four difference patterns in azimuth on receive.
In one embodiment, the antenna is provided having cylindrical shape.
In one embodiment, the probe feeds are oriented at 180 degrees on opposing sides of the cylindrical array.
In one embodiment of the disclosure herein, the antenna is pole-mounted on top of a vehicle.
IBFD antennas provided in accordance with the concepts described herein find application in a wide variety of applications including but not limited to wireless networking applications, wireless communication applications and other applications. It is noted that wireless networking specifications may contain provisions related to vehicle-to-everything (V2X) operation that can enable advanced driving functions, such as collision avoidance, cooperative lane change and remote driving options. In addition to these driving aides, V2X nodes may be tasked with performing multiple simultaneous functions, such as radar, communications and spectral sensing, which can be demanding for a wireless device operating in a traditional time-division duplex mode.
The manner and process of making and using the disclosed embodiments may be appreciated by reference to the figures of the accompanying drawings which form a part this application, and which show, by way of illustration, specific example implementations and are referred to in the following Detailed Description. Other implementations may be made without departing from the scope of the disclosure. It should thus be appreciated that like reference numerals designate corresponding parts throughout the different views and components and structures illustrated in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principals of the concepts described herein. Furthermore, embodiments are illustrated by way of example and not limitation in the figures, in which:
Described is an in-band full-duplex (IBFD) array antenna and system. IBFD antennas and systems provided in accordance with the concepts described herein provide omnidirectional phasing using circular modes and integrating a unique receive adaptive beamforming functionality (which provides direction-finding capability on receive) applicable for use in wireless communications and other applications.
In particular, IBFD systems provided in accordance with the concepts described herein have a direction-finding (DF) capability. Thus, IBFD systems provided in accordance with the concepts described herein provide information indicative of a direction from which signals are received. Such DF information can be used to improve communications links. For example, DF information can be used by one or both of receive and/or transmit systems of an IBDF system. For example, DF information can be used by one or more components of IBDF receive systems (e.g., components in an IBDF receive system such as RF and/or IF receivers and processors) to reduce (and ideally minimize) intentional/unintentional interference from external sources. DF information can also be used by one or more components in an IBDF transmit systems to increase antenna gain in a direction of interest.
Referring now to
IBFD antenna array further comprises a second antenna generally denoted 14. In this example embodiment, antenna 14 comprises one or more sets of four wide-angle short horn antennas 16a-16d fed by respective ones of feed elements (or circuits) 18a-18d. In embodiments, feed elements 18a-18d are provided as probe feeds. Thus, wide-angle short horn antennas are sometimes referred to herein as probe-fed wide-angle short horn antennas.
The probe-fed wide-angle short horn antennas are disposed or otherwise configured to generate difference patterns having pattern segments 19a, 19b, 19c, 19d, which form difference pattern nulls 20a-20d.
In embodiments, the probe feeds 18a-18d (and thus the associated antenna elements) are oriented (both physically and electrically) at 180 degrees from the opposing sets. That is, the antenna elements/probes on opposing sides are fed 180-degrees out of phase. Thus, in the example embodiment of
The difference patterns 19a-19d are achieved using a combination of the physical horn arrangement and the above-described phasing. While DF could be achieved with the physical arrangement alone, the addition of the above-described phasing enables full-duplex capability.
Furthermore, orienting probe feeds at 180 degrees for opposing sets avoids the need for a balun which may otherwise be required to generate difference patterns. Thus, the arrangement of antenna elements and feeds described herein avoids the need for a balun to generate difference patterns.
In the example embodiment of
Omnidirectional antenna 11 may achieve relatively high amounts of isolation between transmit and receive signal paths using circular mode phasing for designs with monopole, horn and monocone elements.
Thus, antenna 10 integrates the use of a circular mode phasing technique with the ability to perform adaptive beamforming on receive.
This added benefit provides an IBFD system comprising such an IBFD antenna with the capability of estimating a signal's direction of arrival, which can improve communication-link performance for vehicle communication systems (e.g., vehicle-to-everything communication systems such as V2X, V2V and V2I systems) and other applications.
Referring now to
To generate difference patterns and implement adaptive beamforming, this example antenna embodiment requires zero (0) analog splitters, four (4) analog combiners and has zero (0) pattern ambiguities. This configuration allows for the combination of opposing pairs with the resulting channel count of four. It should be noted the self-interference (SI) is the same for elements on the first ring (numbers 1-4) and then the second ring (numbers 5-8).
Referring now to
In this example embodiment, the horn antenna elements 30a-30h comprise wide-angle short horn antennas 32 fed by respective ones of probe feed elements 34. The plurality of horn antenna elements 30a-30h are arranged as two sets of four probe-fed wide-angle short horn antenna elements with antenna elements 30a-30d comprising a first set and antenna elements 30e-30h comprising a second set. A first one of the two sets of horn antenna elements is disposed above a second one of the two sets of horn antenna elements.
In this example embodiment, one set of four probe-fed wide-angle short horn antenna elements are physically disposed above a second set of four probe-fed wide-angle short horn antenna elements.
Opposing sets of probe feeds 34 are oriented at 180 degrees to avoid the need for a balun in generating a difference patterns (e.g., such as difference pattern 14 in
As can be seen in
In embodiments, a radome 38 may be disposed over antenna 28. In the example of
In embodiments, commercial off-the-shelf (COTS) power combiners may be used to combine the feeds that are on the opposing sides of cylindrical array 28.
In one example embodiment, antenna elements 30 are tuned for operation at 1.88 GHz and radome 38 is provided from a plastic material having a relative dielectric constant of about 3.0. In embodiments, plastic radome may have a thickness of about ⅛-inch. In embodiments for operation at 1.88 GHz, the overall assembly shown in
It should, of course, be appreciated that antenna 28 may be scaled for operation over a wide range of frequencies. The general principle of combining in-band full-duplex and direction-of-arrival estimation is scalable to other frequency bands. Additionally, increasing a number of antenna elements within the receive array would improve resolution of angle-of-arrival information.
It is also appreciated that incorporation of additional receive arrays in a similar manner would provide for the ability to also discriminate an elevation angle of incoming signals (as opposed to the azimuth-angle information already provided).
In embodiments antenna 28 may be pole-mounted on top of a vehicle. In such embodiments, it would be desirable to provide antenna 28 as compact in size and low in weight.
Referring now to
Receive signal path 44 comprises a receive antenna 50 comprising an array of N antenna elements (where N is an integer greater than or equal to 2) with this example embodiment comprising eight (8) antenna element 52a-52h. Receive Antenna 50 is configured to receive (or intercept) RF signals and provide the RF signals to a combiner network 54.
Combiner network 54 combines the RF (analog) signals provided thereto and provides a set of analog signals (here four analog signals corresponding to receive signals Rx 1-Rx 4) to an M channel receiver 56 where M is an integer greater than or equal to 2. In this example embodiment, receiver 56 is illustrated as a four (4) channel receiver having four inputs and four outputs. Receive 56 comprises an appropriate combination of one or more filter circuits, one or more amplifiers (e.g., low noise amplifiers), one or more downconverter circuits (e.g. RF mixers) and one or more analog to digital converter circuits (DACs) and provides a digital signal (e.g. a stream of digital bits) via one or more digital signal paths 58 (e.g. a bus such as a parallel or serial bus) to an adaptive beamformer network 59 (or more simply, “adaptive beamformer” 59).
Adaptive beamformer 59 implements an adaptive beamforming process to form a plurality of difference beams such as those shown in
In embodiments, adaptive beamforming network 59 utilizes a process to (ideally) maximize signal-to-interference-plus-noise ratio (SINR) in a manner which may be the same as or similar to a Minimum Variance Distortionless Response (MVDR) process. It should, however, be appreciated that unlike MVDR, the adaptive beamforming process does not assume knowledge of the array response in a known signal of interest (SOI) direction. Rather, the adaptive beamforming process uses a known training sequence embedded in the SOI, first by detecting and synchronizing to training data, then estimating the SDI's unknown array response. Those results are used to estimate MVDR-type array weights. The adaptive beamforming process used herein is thus sometimes referred to as “Minimum Variance Distortionless Response (MVDR) for Uncalibrated Arrays (MUA).” The output of adaptive beamformer network may then be provided to one or more processors (not shown in
Referring now to
Referring now to
Referring now to
To generate difference patterns and implement adaptive beamforming, this example antenna embodiment requires four (4) analog splitters, four (4) analog combiners (which may, for example, be provided as part of a combiner network such as combiner network 54 in
Referring now to
It should be noted that to generate difference patterns, and implement adaptive beamforming this example antenna embodiment requires zero analog splitters, four analog combiners (which may, for example, be provided as part of a combiner network such as combiner network 54 in
It is noted that the above assumes the use of four (4) receive channels (hence the reason for ambiguities), As will be appreciated by one of ordinary skill in the art, if a sufficient number of receive channels are used, then it is possible to utilize the configuration of
IBFD antennas provided in accordance with the concepts described herein find application in a wide variety of applications including but not limited to wireless networking applications, wireless communication applications and other applications. It is noted that wireless networking specifications may contain provisions related to vehicle-to-everything (e.g., V2X) operation that can enable advanced driving functions, such as collision avoidance, cooperative lane change and remote driving options. In addition to these driving aides, vehicle-to-everything nodes (e.g., V2X nodes) may be tasked with performing multiple simultaneous functions, such as radar, communications and spectral sensing, which can be demanding for a wireless device operating in a traditional time-division duplex mode.
IBFD technology implemented in accordance with the concepts described herein can alleviate challenges such as the aforementioned challenges by providing a mechanism to access frequency spectrums more efficiently as well as host multiple functions at the same time. One fundamental concept/principle described herein is based on the fact that IBFD techniques enable wireless systems to simultaneously utilize the same frequency band for transmit and receive operation. This concept can help propel the adoption of vehicle-to-everything systems by allowing platforms to not only connect to multiple networks concurrently, but also do so in such a way that the spectral utilization is minimized.
This may be accomplished using tailored antenna designs, including those for vehicles, that offer the initial opportunity to combat the resulting self-interference (SI), and often focus on the direct path coupling of the transmitter to the receiver. Omnidirectional IBFD antennas have demonstrated high amounts of isolation using circular mode phasing for designs with monopole, horn and monocone elements.
While these antennas effectively suppress the SI, they do not provide any insight into the direction from which the signals are received, which can be used to improve communications links. For such a capability, IBFD directional phased arrays have been investigated, but tend to be expensive and complex to operate.
The IBFD antenna concepts described herein provide omnidirectional phasing using the circular modes and integrating a unique receive beamforming functionality suitable for use in wireless communications and other applications.
Although reference is sometimes made herein to particular types of antenna elements, it is appreciated that other antenna elements having similar functional and/or structural properties may be substituted where appropriate, and that a person having ordinary skill in the art would understand how to select such antenna elements and incorporate them into embodiments of the concepts, techniques, and structures set forth herein without deviating from the scope of those teachings.
Various embodiments of the concepts, systems, devices, structures and techniques sought to be protected are described herein with reference to the related drawings. Alternative embodiments can be devised without departing from the scope of the concepts, systems, devices, structures and techniques described herein. It is noted that various connections and positional relationships (e.g., over, below, adjacent, etc.) are set forth between elements in the following description and in the drawings. These connections and/or positional relationships, unless specified otherwise, can be direct or indirect, and the described concepts, systems, devices, structures and techniques are not intended to be limiting in this respect. Accordingly, a coupling of entities can refer to either a direct or an indirect coupling, and a positional relationship between entities can be a direct or indirect positional relationship.
As an example of an indirect positional relationship, references in the present description to providing element “A” over element “B” include situations in which one or more intermediate elements (e.g., element “C”) is between element “A” and element “B” as long as the relevant characteristics and functionalities of element “A” and element “B” are not substantially changed by the intermediate element(s).
The following definitions and abbreviations are to be used for the interpretation of the claims and the specification. As used herein, the terms “comprises,” “comprising, “includes,” “including,” “has,” “having,” “contains” or “containing,” or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a composition, a mixture, process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but can include other elements not expressly listed or inherent to such composition, mixture, process, method, article, or apparatus.
Additionally, the term “exemplary” is used herein to mean “serving as an example, instance, or illustration. Any embodiment or design described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments or designs. The terms “one or more” and “one or more” are understood to include any integer number greater than or equal to one, i.e. one, two, three, four, etc. The terms “a plurality” are understood to include any integer number greater than or equal to two, i.e. two, three, four, five, etc. The term “connection” can include an indirect “connection” and a direct “connection”.
References in the specification to “one embodiment, “an embodiment,” “an example embodiment,” etc., indicate that the embodiment described can include a particular feature, structure, or characteristic, but every embodiment can include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.
For purposes of the description hereinafter, the terms “upper,” “lower,” “right,” “left,” “vertical,” “horizontal, “top,” “bottom,” and derivatives thereof shall relate to the described structures and methods, as oriented in the drawing figures. The terms “overlying,” “atop,” “on top, “positioned on” or “positioned atop” mean that a first element, such as a first structure, is present on a second element, such as a second structure, where intervening elements such as an interface structure can be present between the first element and the second element. The term “direct contact” means that a first element, such as a first structure, and a second element, such as a second structure, are connected without any intermediary elements.
Use of ordinal terms such as “first,” “second,” “third,” etc., in the claims to modify a claim element does not by itself connote any priority, precedence, or order of one claim element over another or the temporal order in which acts of a method are performed, but are used merely as labels to distinguish one claim element having a certain name from another element having a same name (but for use of the ordinal term) to distinguish the claim elements.
The terms “approximately” and “about” may be used to mean within ±20% of a target value in some embodiments, within ±10% of a target value in some embodiments, within ±5% of a target value in some embodiments, and yet within ±2% of a target value in some embodiments. The terms “approximately” and “about” may include the target value. The term “substantially equal” may be used to refer to values that are within ±20% of one another in some embodiments, within ±10% of one another in some embodiments, within ±5% of one another in some embodiments, and yet within ±2% of one another in some embodiments.
The term “substantially” may be used to refer to values that are within ±20% of a comparative measure in some embodiments, within ±10% in some embodiments, within ±5% in some embodiments, and yet within ±2% in some embodiments. For example, a first direction that is “substantially” perpendicular to a second direction may refer to a first direction that is within ±20% of making a 90° angle with the second direction in some embodiments, within ±10% of making a 90° angle with the second direction in some embodiments, within ±5% of making a 90° angle with the second direction in some embodiments, and yet within ±2% of making a 90° angle with the second direction in some embodiments.
It is to be understood that the disclosed subject matter is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The disclosed subject matter is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting. As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods, and systems for carrying out the several purposes of the disclosed subject matter. Therefore, the claims should be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the disclosed subject matter.
Although the disclosed subject matter has been described and illustrated in the foregoing exemplary embodiments, it is understood that the present disclosure has been made only by way of example, and that numerous changes in the details of implementation of the disclosed subject matter may be made without departing from the spirit and scope of the disclosed subject matter.
Accordingly, it should be understood that subject matter defined in the appended claims is not necessarily limited to the specific implementations described above. The specific implementations described above are disclosed as examples only.
This application claims the benefits of U.S. Provisional Application No. 63/368,110 filed on Jul. 11, 2022. The entire contents of this application is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 63368110 | Jul 2022 | US |
