Directional antenna arrays and methods

Abstract

Disclosed are devices, systems and methods employing a directional antenna with a single rotational degree of freedom and using multiple signal-quality measurements to define best orientation with respect to a remote communication point and to align the antenna along the highest-signal-quality path. This simplifies alignment upon installation and facilitates higher signal levels, resulting in more reliable communication and higher data throughput.

Claims

1. A tunable communication device comprising: an antenna body, the antenna body comprising: a side wall, the side wall including a substantially planar face; an upper surface; an interior surface; and an exterior surface; a directional antenna array comprising one or more directional antennas mounted on the exterior surface of the substantially planar face of the partially cylindrical antenna body, the one or more directional antennas facing a single direction; an antenna driver configured to control a rotation of the antenna body around a single axis to point the directional antenna array in a direction within a plane of rotation; a cylindrical radome enclosing the partially cylindrical antenna body; and a signal quality evaluator module configured to: initiate a course scan through evaluation of a quality of input signals received from the one or more directional antennas as the antenna body is rotated through a plurality of coarse discrete positions in the plane of rotation; determine a subset of the plurality of coarse discrete positions that correlate with a highest antenna signal quality as the antenna body is rotated through the plurality of coarse discrete positions; and initiate a fine scan in which the antenna body is rotated through a plurality of fine discrete positions within the subset of the plurality of coarse discrete positions, the plurality of fine discrete positions being of a smaller angular range as compared with the plurality of coarse discrete positions.

2. The tunable communication device of claim 1, wherein the one or more directional antennas are configured to communicate with a remote station.

3. The tunable communication device of claim 2, wherein the remote station comprises a Wi-Fi access point.

4. The tunable communication device of claim 2, wherein the remote station comprises a cellular base station.

5. The tunable communication device of claim 1, wherein the interior of the partially cylindrical antenna body encloses one or more electronic systems.

6. A method of operating a tunable communication device, the tunable communication device having a directional antenna array comprised of one or more directional antennas mounted on an exterior surface of a face of a rotatable antenna body, the method comprising: rotating the tunable communication device through a plurality of coarse angular positions to point the directional antenna array in a series of discrete directions within a plane of rotation; receiving a signal from a base station at each of the plurality of coarse angular positions of the tunable communication device; determining a quality of the signal received from the base station at each of the plurality of coarse angular positions of the tunable communication device; determining a highest quality signal from the plurality of signals received through each of the plurality of coarse angular positions to determine a subset of the plurality of coarse angular positions; and rotating the tunable communication device through a plurality of fine angular positions within the determined subset of the plurality of coarse angular positions, the plurality of fine angular positions being of a smaller angular range as compared with the plurality of coarse angular positions.

7. The method of claim 6, wherein the rotating of the tunable communication device further comprises: selecting a rotational range smaller than an entire rotational range of the antenna body on either side of the determined highest quality signal; rotating the partially cylindrical antenna body to one end of the smaller rotational range; receiving a plurality of signals during rotation within the smaller rotational range by: rotating the tunable communication device through the plurality of fine angular positions within the smaller rotational range; receiving a signal from the antenna at each of the plurality of fine angular positions of the tunable communication device within the smaller rotational range; determining quality of the signal received at each of the plurality of fine angular positions of the tunable communication device within the smaller rotational range; identifying a highest quality signal among the plurality of signals received for the smaller rotational range; and rotating the antenna body to an orientation corresponding to the highest quality signal identified within the smaller rotational range.

8. The method of claim 6, further comprising: monitoring a quality of the antenna signal, and upon receiving a signal that is below a threshold value, repeating the process of rotating the tunable communication device through the plurality of coarse angular positions to point the directional antenna array in the series of discrete directions within the plane of rotation.

9. A tunable communication system, the system comprising: a tunable communication device comprising an antenna body, the antenna body comprising: a side wall including a substantially planar face; an upper surface; an interior surface; and an exterior surface; one or more directional antennas mounted on the exterior surface of the substantially planar face of the antenna body, the one or more directional antennas facing a single direction; an antenna driver configured to control rotation of the antenna body around a single axis to point the one or more directional antennas in a plurality of directions within a plane of rotation; a cylindrical radome enclosing the antenna body; and a signal quality evaluator module configured to: initiate a course scan through evaluation of a quality of input signals received from the one or more directional antennas as the antenna body is rotated through a plurality of coarse discrete positions in the plane of rotation; determine a subset of the plurality of coarse discrete positions that correlate with a highest antenna signal quality as the antenna body is rotated through the plurality of coarse discrete positions; and initiate a fine scan in which the antenna body is rotated through a plurality of fine discrete positions within the subset of the plurality of coarse discrete positions, the plurality of fine discrete positions being of a smaller angular range as compared with the plurality of coarse discrete positions; and a remote station in communication with the tunable communication device.

10. The tunable communication system of claim 9, wherein the one or more directional antennas are configured to communicate with the remote station.

11. The tunable communication system of claim 10, wherein the remote station is at least one of a Wi-Fi access point, and a cellular base station.

12. The tunable communication device of claim 9 wherein the signal quality evaluator module is further configured to: compare the quality of input signals received from the one or more directional antennas with one another; and generate a route signal to instruct the antenna driver to steer the antenna towards an orientation corresponding to the highest antenna signal quality.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The novel features of the invention are set forth with particularity in the appended claims. A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings of which:

(2) FIG. 1A is an isometric illustration of the disclosed antenna system;

(3) FIG. 1B is an isometric illustration of an antenna assembly according to the disclosure;

(4) FIG. 2 is a block diagram of an antenna system according to the disclosure which depicts the functional interaction of various elements in the system; and

(5) FIG. 3 is a high-level flow chart illustrating an antenna orientation algorithm by which the orientation of the antenna of disclosed system with respect to that of a remote antenna may be established and maintained during operation.

DETAILED DESCRIPTION

(6) Referring now to FIG. 1A, an isometric view of an exemplar system is presented. The antenna system 100 comprises the following elements: a radome enclosure 104, and an antenna assembly 102, a component of which is a directional antenna. The antenna assembly 102 comprises the antenna body 108, electric motor 112, driver module 116, and a signal quality evaluator module (SQEM) 122. The radome enclosure 104 is a closed hollow cylinder of circular cross-section which completely encases antenna assembly 102. The radome enclosure 104 is transparent to radio waves and provides protection from the elements for antenna assembly 102. The long axis of the radome enclosure 104 is parallel to the z-axis of coordinate system 126. The cross-section of the radome enclosure 104 is circular and lies parallel to the x-y plane of coordinate system 126. The cross-sectional radome radius R1 106 is sufficiently larger than the antenna body major radius R2 110 to allow free rotation of the antenna body 108 about the z-axis of coordinate system 126 within the radome enclosure 104.

(7) In the embodiment depicted in FIG. 1A, the upper spindle 124 protrudes from the antenna body top surface 136, coincident with the z-axis of coordinate system 126. The upper spindle 124 engages the radome enclosure 104 while retaining a rotational degree of freedom about the z-axis of coordinate system 126, freeing the antenna body 108 to rotate within the radome enclosure 104. The electric motor 112, driver module 116, and SQEM 122 reside within, and are rigidly attached to radome enclosure 104. The motor driveshaft 120 is rigidly coupled to the antenna body 108 enabling rotation of the antenna body 108 about the z-axis of coordinate system 126 when sufficient motive torque is supplied by the electric motor 112. Note that other physical configurations are possible in different embodiments, including for example, a configuration in which the electric motor 112, driver module 116, and SQEM 122 reside within the antenna body 108. Other embodiments may entail one or two of the electric motor 112, driver module 116, and SQEM 122 residing inside antenna body with the remaining elements residing outside the antenna body 108 and within the radome enclosure 104. Still other embodiments may entail one or more of the electric motor 112, driver module 116, and SQEM 122 residing external from the radome enclosure 104.

(8) FIG. 1B is an isometric view of an exemplar antenna body 108. The antenna body 108 takes the form of a cylinder of truncated circular cross-section with sufficient volume to house electronics associated with antenna assembly 102. Referring to coordinate system 126, the long axis of the antenna body 108 is parallel to the z-axis. The planar truncation runs parallel to the y-z plane of coordinate system 126, which results in a planar rectangular surface that forms the antenna face 128. Antenna 132, depicted as a rectangle, is a directional antenna which resides on antenna face 128. Although antenna 132 is depicted as a rectangle, it may take a number of physical forms; antenna 132 may, for example, comprise a single element antenna or a multi-element antenna array. As will be appreciated by those skilled in the art, the antenna face could be convex, concave or flat.

(9) Note that other physical configurations are possible in different embodiments, including for example, one in which an antenna body is entirely cylindrical and a conformal antenna array resides upon the cylindrical exterior of the antenna body. Still other embodiments may contain more than one planar surface, each with an antenna array residing upon it.

(10) FIG. 2 is a block diagram depiction of the disclosure. In the context of this communications system, the remote station 200 represents the remote end of a wireless communications link, wherein the geographic position and orientation of the remote station 200 is unknown or not precisely known. Examples of the communications system this scheme may apply to include, for example, Wi-Fi and cellular communications systems and any other systems having a remote wireless remote station.

(11) The system illustrated in the block diagram, comprising antenna 132 (FIG. 1B), antenna body 108 (FIG. 1A), electric motor 112 (FIG. 1A), driver module 116 (FIG. 1A), and the SQEM 122 (FIG. 1A), may be either fixed or moving with respect to remote station 200. The remote station 200 can be a base station.

(12) The antenna 132 (FIG. 1B) receives an incoming RF energy input and produces a conducted antenna signal 210 which is sent both to the SQEM 122 (FIG. 1A) and out to external electronics via antenna line feed 212. Upon receiving the conducted antenna signal 210 as an input, the SQEM 122 (FIG. 1A) monitors, evaluates, and records the signal quality. Evaluation of the signal quality may be accomplished via any number of schemes, including, for example, magnitude, code correlation, or some combination thereof. The SQEM 122 may be implemented purely in hardware, as software for instance in a microcontroller, or via some hybrid of the two, as desired.

(13) If warranted by the results of the evaluation of the quality of the conducted antenna signal 210, the SQEM 122 implements one of a diversity of algorithms to engage driver module 116 to reorient the antenna body 108 to point the antenna 132 towards the remote station 200 according to any of a diversity of signal optimization schemes. Such a feedback loop allows for a diversity of search and signal quality optimization algorithms to converge on the best possible signal for a given placement of the disclosed device.

(14) Driver module 116 may be implemented purely in hardware, as software for instance in a microcontroller, or via some hybrid of the two. Driver module 116 is configurable to receive from the SQEM 122 a driver instruction signal 216 corresponding to a target orientation. The driver module 116 then maps the driver instruction signal onto necessary time-variant driver signals required to drive the orientation of the antenna body 108. The driver module 116 then sends a motor control signal 220 to electric motor 112, which then rotates the antenna body 108 through the appropriate angle to achieve desired alignment of antenna assembly 102. In addition, the driver module 116 sends antenna position data back to the SQEM 122 that allows the SQEM 122 to correlate signal quality information with the angular position of antenna 132. In operation, the antenna 132 can eventually be steered to an optimal orientation with respect to remote station 200 given the position of antenna system 100 (FIG. 1A) with respect to remote station 200.

(15) The system can also dynamically adapt to a changing signal quality and orientation. Note that the maximum speed permissible for the disclosed system to still function is limited by the speed of the system's ability to converge to and lock onto an orientation that keeps the signal quality of the signal above a minimally accepted threshold.

(16) Specific applications of the disclosed system include:

(17) TABLE-US-00001 TABLE 1 ANTENNA APPLICATIONS Pointing X where X is at a Y where Y is Radio Radio station TV TV Station Satellite Satellite Marine Radio Naval or Coast Guard Transmitter Wifi Wifi transmitter Cellular Cellular Transmitter Receiving Transmitter Antenna

(18) FIG. 3 is a high-level flow chart illustrating one version of an antenna orientation algorithm 300 by which the orientation of the antenna of disclosed system with respect to that of a remote antenna may be established and maintained during operation. The antenna orientation algorithm 300 comprises two components: an orientation phase 350 and a maintenance phase 360. The orientation phase 350 occurs either following first installation of the antenna system 100 (FIG. 1A) or when antenna signal quality, Q.sub.A, falls below a threshold signal quality, Q.sub.T, and cannot be recovered above Q.sub.T via the steps in the maintenance phase 360. The orientation phase 350 assumes that the position of the remote station, with which antenna system 100 (FIG. 1A) is attempting to communicate, is not precisely known and lies within the angular range, R.sub.A, and of rotation of antenna system 100 (FIG. 1A). For example, if antenna system 100 (FIG. 1A) has an R.sub.A of 360°, the position of the remote station could lie anywhere inside a complete circle with respect to antenna system 100

(19) (FIG. 1A). As another example, if the angular range, R.sub.A, of antenna system 100 (FIG. 1A) is only 90°, the position of the remote station would need to lie in a quarter-circle encompassed by R.sub.A.

(20) The purpose of the maintenance phase 360 is to monitor antenna signal quality, Q.sub.A, and to re-orient the antenna within a limited angular range under two conditions: 1) orientation phase 350 is complete, and 2) antenna signal quality, Q.sub.A, falls below a threshold signal quality, Q.sub.T. When these two conditions are met, maintenance phase 360 initiates a sequence of steps to bring Q.sub.A≥Q.sub.T. There are two possible outcomes. If maintenance phase 360 fails to result in Q.sub.A≥Q.sub.T, then the orientation phase 350 is re-initiated. Conversely, if maintenance phase 360 results in Q.sub.A≥Q.sub.T, then the system remains in maintenance phase 360, monitoring Q.sub.A.

(21) Now, examining FIG. 3, orientation phase 350 is initiated upon a line feed of the antenna signal 304 entering the SQEM 122 (FIG. 1A) for evaluation. SQEM 122 (FIG. 1A) initiates a coarse scan 308 across the entire angular range, R.sub.A, of the antenna system 100 (FIG. 1A). The first step of the coarse scan 308, the driver module 116 (FIG. 1A) commands the motor to rotate the antenna 132 (FIG. 1A) to one end of the angular range, R.sub.A, upon which the SQEM 122 (FIG. 1A) receives the antenna signal 304, then calculates and stores antenna signal quality, Q.sub.A. Next, the SQEM 122 (FIG. 1A) sends a command to driver module 116 (FIG. 1A), which in turn signals commands the motor to rotate the antenna body 108 through a coarse scan interval, I.sub.C. For example, if the angular range, R.sub.A, of the antenna system is 160°, the coarse scan interval, I.sub.C, might be 10°. Once the rotation through one coarse scan interval is complete, the SQEM 122 (FIG. 1A) receives the antenna signal 304, then calculates and stores the antenna signal quality value. The process is repeated throughout the entire angular range, R.sub.A, resulting in a set of pairs of signal quality/angle values, Q.sub.Ai/A.sub.Ci.

(22) Once the coarse scan 308 is complete, the next step is determination of the fine scan range 312. The SQEM 122 (FIG. 1A) may use any number of schemes or methods to arrive at the fine scan range, R.sub.F. For example, the fine scan range, R.sub.F, may be defined by taking a range, equal to one coarse scan interval, I.sub.C, on either side of one or more of the highest antenna signal qualities determined in the coarse scan 308. The fine scan interval may be determined in any of a number of ways. For example, it may be pre-determined based on physical characteristics of the antenna, required robustness, necessary accuracy, size of the coarse scan interval, I.sub.C, etc., or it may be defined when the fine scan range is determined, based upon, for example, the span of the fine scan range. Conceptually, dividing the scan into coarse and fine steps can increase the speed at which the system converges upon an orientation providing the best signal quality under the given conditions. Such a system can also dynamically adapt to a changing signal quality and orientation. Note that the maximum speed permissible for the disclosed system to still function is limited by the speed of the system's ability to converge to and lock onto an orientation that keeps the signal quality above a minimally acceptable threshold to support the required communication data rate.

(23) The next step in the orientation phase 350 is the fine scan 316. The fine scan 316 is similar to the coarse scan with fine scan range, R.sub.F, replacing angular range, R.sub.A, and fine scan interval, I.sub.F, replacing coarse scan interval, I.sub.C. The SQEM 122 (FIG. 1A) initiates the fine scan 316 across the entire angular range, R.sub.A, of the antenna system 100 (FIG. 1A). The first step of the fine scan 316, the driver module 116 (FIG. 1A) commands the motor to rotate the antenna 132 (FIG. 1A) to one end of the fine scan range, R.sub.F, upon which the SQEM 122 (FIG. 1A) receives the antenna signal 304, then calculates and stores antenna signal quality, Q.sub.A. Next, the SQEM 122 (FIG. 1A) sends a command to driver module 116 (FIG. 1A), which in turn signals commands the motor to rotate the antenna body 108 through a fine scan interval, I.sub.F. Once the rotation through one fine scan interval is complete, the SQEM 122 (FIG. 1A) receives the antenna signal 304, then derives and stores the antenna signal quality value. The process is repeated throughout the entire fine scan range, R.sub.F, resulting in a set of pairs of signal quality/angle values, Q.sub.Ai/A.sub.Fi.

(24) Once the fine scan 316 is complete, the final step in the orientation phase 350 orientation of antenna at angle A.sub.QMAX 320, corresponding to the highest antenna signal quality, Q.sub.MAX. The SQEM 122 (FIG. 1A) sends A.sub.QMAX to the driver module 116 (FIG. 1A), which then commands the motor to rotate the antenna 132 (FIG. 1A) to A.sub.QMAX. Optionally, once maximum signal quality, Q.sub.MAX, is known, the minimally acceptable threshold signal quality, Q.sub.T, value may be established or modified according to a number of measures, for instance, as a percentage of Q.sub.MAX. Otherwise, the minimally acceptable threshold signal quality, Q.sub.T, may be pre-determined and fixed. Once orientation of antenna at angle A.sub.QMAX 320 is complete, the system enters maintenance phase 360.

(25) The purpose of maintenance phase 360 is to monitor signal quality, Q.sub.A, and to perform or initiate one or more action sequences if signal quality, Q.sub.A falls below a threshold signal quality, Q.sub.T. Upon initiation of maintenance phase 360, a line feed of the antenna signal 304 enters the SQEM 122 (FIG. 1A) at a specific periodic rate. Each time a signal is received by the SQEM 122 (FIG. 1A), its antenna signal quality, Q.sub.A, is evaluated 324 and compared 328 against a minimally acceptable threshold signal quality, Q.sub.T. If antenna signal quality, Q.sub.A, is greater than or equal to threshold signal quality, Q.sub.T, no action is taken and the SQEM 122 (FIG. 1A), and system state reverts to 324, awaiting the next periodic line feed of the antenna signal 304 for evaluation. If antenna signal quality, Q.sub.A, falls below threshold signal quality, Q.sub.T, the SQEM 122 (FIG. 1A) initiates fine scan 332, which is identical to fine scan 316. Upon completion of fine scan 332, the SQEM 122 (FIG. 1A), again evaluates antenna signal quality, Q.sub.A. Antenna signal quality, Q.sub.A, is then compared 338 against a threshold signal quality, Q.sub.T. If antenna signal quality, Q.sub.A, is greater than or equal to threshold signal quality, Q.sub.T, the SQEM 122 (FIG. 1A) sends antenna angle A.sub.QMAX 320, corresponding to the highest antenna signal quality, Q.sub.MAX to the driver module 116 (FIG. 1A), which then commands the motor to rotate the antenna 132 (FIG. 1A) to the orientation corresponding to Q.sub.MAX. The system state then reverts to 324, awaiting the next periodic line feed of the antenna signal 304 for evaluation. However, if antenna signal quality, Q.sub.A, remains below threshold signal quality, Q.sub.T, the system reverts to orientation phase 350, beginning the entire process once again.

(26) While preferred embodiments of the present invention have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the invention. It should be understood that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention. It is intended that the following claims define the scope of the invention and that methods and structures within the scope of these claims and their equivalents be covered thereby.