System and method for real-time multiplexing phased array antennas to modems

Abstract

To provide an antenna system for satellite communication that includes a platform upon which several phased antenna arrays are mounted and which can communicate with satellites, and that is capable of being reconfigured in real time.SOLUTION: An asset 200 capable of communicating with a plurality of satellites can couple a plurality of computers 1 to n to any modems MD1 to MDn via a router 210, and can couple the plurality of modems MD1 to MDn to any antennas ESA1 to ESAn via a switch mechanism 205. The plurality of antennas ESA1 to ESAn are composed of phased array antennas and theses can be changed and controlled by a control circuit 215.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] (Related Application) This disclosure claims the benefit of priority based on U.S. Provisional Application No. 62 / 874,447, filed on Jul. 15, 2019, the entire disclosure of which is incorporated herein by reference.

[0002] This disclosure generally relates to the field of wireless communications, such as satellite-based communications and two-point communications using microwaves, and to the control of multiple phased array antennas communicating with multiple antennas.

Background Art

[0003] (Related Technology) Satellite-based communication is a common way for ships, airplanes, trains, and people to connect to the global Internet. The connection methods vary from simple connections at low frequencies to complex and expensive connections at high frequencies.

[0004] The complexity is mainly related to the antenna. For higher frequency communications, antennas that point to satellites are needed. The user may move, and although the satellite is relatively fixed to the Earth, the antenna may have to maintain its orientation towards the satellite. There may also be cases where the satellite moves and the antenna has to constantly maintain its pointing direction towards the satellite. In either case, an autopilot antenna that can maintain the direction control has important advantages. The reverse is also true. In many cases, the satellite itself needs to direct a beam to a specific location on the Earth. In any case, there are transmitters and receivers, and one or both of the two may need to operate the beam to make their respective connections.

[0005] There are two forms of automatic steering antenna systems. They are either a mechanically steered antenna (MSA) used in combination with a motor assembly that steers a certain form of a parabolic dish, patch array, or other planar and three-dimensional antenna design directly or through some kind of amplification lens towards a receiver, or an electronically steerable array (ESA) that uses various forms to electronically steer the beam without moving parts, such as through the phase shift of a phased array antenna.

[0006] A common way to describe the performance of components such as antenna systems is SWAP-C+R, which represents size, weight, power consumption, cost, and reliability. These are some of the main factors in determining whether an antenna system is suitable for a particular purpose. As each of the variables increases, the number of applicable use cases for the antenna decreases. For example, in trains, a low-profile antenna is required to be able to pass through tunnels, and in airplanes as well, a low-profile antenna is required to minimize drag and reduce vortices that significantly affect flight characteristics. MSA has the drawback of being physically large in the height direction and has low reliability because moving parts wear out over time. ESA usually consumes a large amount of power and has the drawback of being heavy due to the heat sink or other heat dissipation solutions related to that power. Despite being physically smaller than MSA, it is still very thick and thus ultimately expensive. However, ESA is usually more suitable for certain use cases because it is smaller in size and more reliable than MSA.

[0007] Another important variable in antenna design is the aperture size. The aperture size represents the effective collecting surface area of the antenna. This is usually a certain form of x and y coordinates and the transmission Represents the surface area presented to the satellite. The most desirable antenna always faces the source and has a large aperture (x and y) without z (height / thickness). The larger the aperture size, the higher the gain of the received or transmitted signal, and thus the spectral efficiency of the overall system is improved, i.e., a higher data rate can be obtained with less bandwidth, which would be a significant advantage in the market. Furthermore, the higher the gain, the less likely the transmitted beam will misdirect power and cause interference in unintended directions. This is because the higher the gain, the narrower the beam. Additionally, the narrow beam of a high-gain antenna makes the antenna less likely to receive such unintended interference. From the perspective of signal strength, a larger x / y surface area, i.e., aperture, is required, which can also reduce the power amplifier level required for a given connection, i.e., the power that needs to be supplied to the antenna.

[0008] The problem associated with the aforementioned technology is that when SWAP-C+R is large, the applications of the antenna system are limited. The most efficient beam is the direct beam to the front of the antenna itself, called the boresight. The boresight is a straight line perpendicular to the radiating surface of the antenna, above the center of the antenna. Since the MSA can rotate the entire antenna, it can maintain the boresight to the satellite and thereby maintain the aperture size presented to the satellite. Conversely, since the ESA tilts the beam electronically, the apparent aperture presented to the satellite becomes smaller, and thus the performance decreases by a factor of 2 to 4 depending on the off-angle axis on the receiving and transmitting sides. Also, due to the technical reduction in size, a scanning loss of 10*log10COSΘ occurs, which is directly related to the apparent area, i.e., the aperture dimension as seen from the steering direction. There is no scanning loss in the MSA, but a large scanning volume is required to maintain the pointing direction. This increases both the size and weight. In some cases, the antenna combines both the ESA and MSA in a single antenna, using the ESA for one direction, probably the azimuth, and the mechanical steering assembly for the elevation direction. These show a well-balanced SWaP-C+R for the application.

[0009] Another problem with current antenna systems is that, due to physical size, often the receive and transmit antenna assemblies are limited to only one per application. For example, an aircraft requires steerable antennas to maintain a connection with satellites. However, due to SWaP-C, the number of steerable antennas is limited to one. As a result, when the aircraft banks and turns, the connection to the satellite is lost.

[0010] Also, often terminals need to connect to multiple satellites simultaneously. Furthermore, since each satellite may require a special modem with a special waveform, it may be necessary to switch the modem / antenna combination as needed.

[0011] Therefore, technologies for improving satellite communication are needed.

Summary of the Invention

[0012] The following summary of the disclosure is provided to offer a basic understanding of some aspects and features of the present invention. This summary is not an extensive overview of the present invention and is not intended to particularly identify the main or important elements of the present invention or to delineate the scope of the present invention. Its sole purpose is to present some concepts of the present invention in a simplified form as a prelude to the more detailed description presented below.

[0013] Embodiments of the disclosure enable multiplexing of multiple antennas and modems, thus allowing different modem / antenna combinations to be configured and thereby enabling on-the-fly generation of transmission paths.

[0014] The disclosed embodiments can improve the control of communication paths between communication devices and satellites. The disclosure In the following embodiments, any available communication path is configured in real time based on parameters such as available satellites, the received signal strength from each available satellite, the amount and type of data to be transmitted, the transmission cost in each communication path, the user's subscription, and the like, such as account permissions for using any of the available communication paths.

[0015] According to the disclosed embodiments, real-time control of mobile platforms and inter-satellite communication becomes possible, for example, while maintaining a communication channel regardless of the movement of a platform such as an airplane or a ship. In the platform, there are a plurality of phased array antennas, each of which can have a boresight pointing in a different direction (for example, up, left, right, etc.) with respect to the platform. When the platform moves, for example, turns, the controller can determine the best antenna to use for transmission and can select and deselect antennas in real time such that it always selects the antenna with the best RSSI (received signal strength).

[0016] In the disclosed embodiments, a plurality of ESAs, for example, by using variable dielectric technology in the phase shifters of the ESA, adopt a lower SWaP-C ESA form. By utilizing variable dielectrics, new connection methods become possible for both satellite and terrestrial antenna systems, and these new connection forms are particularly advantageous for the embodiments disclosed herein.

[0017] Encryption of data is often used for security purposes, but encryption has limitations with the advent of quantum computing. Therefore, in the disclosed embodiments, a plurality of satellites are utilized to split data across at least one satellite and a plurality of other paths and recombine this data at a secure location. Thus, even if an individual path is intercepted, it only represents a part of the encrypted data file. Therefore, the disclosed aspect provides a more secure file transfer mechanism.

[0018] In other cases, it is necessary to use multiple ESAs as follows. That is, when a platform such as a train or an airplane moves and turns, it is the case of selecting the ESA facing the maximum bore site for maximum efficiency. Such a mechanism for automatically switching between ESAs is provided by the embodiments disclosed herein.

[0019] In still other cases, there are rapid transitions and interferences between multiple ESAs, that is, it may be necessary to reduce the aperture size, and it is further necessary to enable the use of multiple ESAs and potentially arrange them at odd angles to each other, and further the distance between these ESAs may be important. A method of using very low SWaP-C ESAs, dynamically combining the signal strengths of these multiple ESAs, and potentially dynamically changing the modem associated with such various combinations of ESAs is also provided by the disclosed embodiments. By dynamic, it means managing in real time such that each of the various connections can be replaced or deleted at any instant, or a new connection can be added as advantageous depending on the transmit / receive situation.

[0020] In still other cases where there are multiple ESAs, a baseband solution may be included that provides several MIMOs that provide zeroing or other baseband functions, either digitally or analogously, to improve the data rate.

[0021] In the disclosed embodiments, a satellite communication antenna system is provided, including a plurality of antennas each including a phased array radiator, a plurality of modems, a switch for dynamically coupling any of the aforementioned antennas to any of the aforementioned modems, a plurality of communication devices, a router for dynamically coupling any of the aforementioned communication devices to any of the aforementioned modems, and the aforementioned switch and a controller for controlling the router to provide real-time instructions for connecting the aforementioned plurality of antennas, the aforementioned plurality of modems, and the aforementioned plurality of communication devices.

[0022] In a general aspect, the system includes a plurality of phased array antennas mounted on a mobile platform for satellite communication, each having a plurality of radiators and a plurality of phase shifters that introduce a delay into the RF signals propagating therethrough respectively; at least one phase controller that operates the phase shifters to introduce the aforementioned delays into the aforementioned RF signals; a plurality of modems; a switch operable to connect any of the aforementioned modulators / demodulators to any of the aforementioned phased array antennas in real time as determined; a communication device; a router operable to route signals between any of the aforementioned modulators / demodulators and the aforementioned communication device; a control circuit that provides instructions to the aforementioned switch to form a connection between the aforementioned modulator / demodulator and any of the aforementioned phased array antennas, and to the aforementioned router to route signals between the aforementioned modulator / demodulator and any of the aforementioned communication devices in real time.

[0023] In a general aspect, a method for controlling communication of a plurality of phased array antennas and a plurality of satellites is provided, which includes receiving an instruction of data to be transmitted from a computer device to a satellite, determining a satellite available for communication, instructing the phased array antennas to face the selected satellite, receiving a received signal strength (RSSI) signal from the phased array antennas, selecting a phased array antenna for transmission based on the RSSI signal, connecting the selected phased array antenna for transmission to a selected modulator, operating a router to connect the modulator to the computer device, and starting transmission of the data to be transmitted.

[0024] In a further aspect, a method for combining transmission signals received by a plurality of antennas is disclosed, which calculates the cross-correlation coefficients of the signals obtained from each of the plurality of antennas described above, selects the signal that generates the highest coefficient as the golden reference signal, uses the golden reference signal to time-align the transmission signals received by the plurality of antennas, derives the peak power to average power ratio for each of the transmission signals received by the plurality of antennas, generates the weighting coefficients for each of the transmission signals received by the plurality of antennas using the cross-correlation coefficients and the peak power to average power ratio, applies the foregoing weighting coefficients to each of the transmission signals received by the plurality of antennas to generate a plurality of weighted signals, and sums the foregoing plurality of weighted signals. This method may further include calibrating the phases of the transmission signals received by the plurality of antennas using the golden reference signal.

[0025] According to another aspect, a system provided for receiving a transmission signal includes a plurality of antennas each receiving a received signal, a ranking module that ranks the plurality of antennas according to the quality of each received signal, generates a corresponding level 1 signal, and selects the highest-ranked antenna as the golden reference signal, a synchronizer that synchronizes all the received signals of the plurality of antennas using the golden reference signal, a level 2 module that calculates the peak-to-average power ratio for each of the received signals of the plurality of antennas and generates a corresponding level 2 signal, a scoring unit that generates a weighting score for each of the received signals of the plurality of antennas using the foregoing level 1 signal and level 2 signal, a weighting module that applies the foregoing weighting score to each of the corresponding received signals of the plurality of antennas to generate a plurality of weighted signals, and a summing module that synthesizes all of the foregoing weighted signals. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate examples of embodiments of the present invention and, together with the description, serve to explain and illustrate the principles of the present invention. The drawings are intended to schematically show the main features of the examples of the embodiments. The drawings are not intended to illustrate all the features of actual embodiments or to depict the relative dimensions of the elements shown and are not drawn to scale. It is not intended to and is not drawn to scale.

[0027] One or more embodiments of the present invention are illustrated by way of example and are not limited to the accompanying drawings. In the accompanying drawings, like reference numerals indicate like elements.

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DETAILED DESCRIPTION OF THE INVENTION

[0028] Embodiments of the real-time multiplexing antenna and control according to the present invention will be described with reference to the drawings. Different embodiments or combinations thereof may be used for different applications or to achieve different benefits. Depending on the results to be achieved, the different features disclosed herein can be utilized partially or maximally, alone or in combination with other features, to balance requirements, constraints, and advantages. Therefore, even if some advantages are emphasized with reference to different embodiments, the disclosure is not limited to the disclosed embodiments. That is, the features disclosed herein are not limited to the embodiments in which they are described, but can be "mixed and matched" with other features and incorporated into other embodiments.

[0029] Note that the references to satellites, platforms, or terminals in this specification are interchangeable and for illustrative purposes only. The physical locations can also be interchanged so that steerable beams and their effects can originate from satellites, platforms, terminals, or all of them. The same applies to reception and transmission. Either side can be the receiving side or the transmitting side, and the use of the terms receiving side or transmitting side is for illustrative purposes only and does not limit the reverse or even simultaneous communication of reception and transmission.

[0030] In many types of RF antennas, reception and transmission are symmetric with respect to each other, and a description of one applies equally to the other. In this description, it may be simpler to describe transmission, and reception will be the same, just in the opposite direction. Also, in the disclosed embodiments, it is contemplated that the disclosed antenna is mounted or integrated on a platform and its main beam is directed towards another antenna, which may also be referred to herein as a target. Also, the target antenna may also be mounted on a platform, and one or both platforms may be moving. For example, the antenna may be mounted on a vehicle such as an airplane, a ship, an automobile, etc., and its target may be, for example, attached to a satellite. The concept of symmetry also applies here, and the antenna may be mounted on a satellite and its target may be mounted on a vehicle. It is also assumed that the target antenna is mounted on a platform, and one or both platforms may be moving. For example, the antenna may be mounted on a vehicle such as an airplane, a ship, an automobile, etc., and its target may be, for example, attached to a satellite. The concept of symmetry also applies here, and the antenna may be mounted on a satellite and its target may be mounted on a vehicle.

[0031] FIG. 1 shows a phased array antenna, also referred to as an electronically steerable or scanning array, which may be used in any of the embodiments disclosed herein. A phased array refers to an array of radiators that form a main beam, and the direction of the main beam can be electronically steered by changing the phase / time delay of the RF energy reaching each radiator. For simplicity, the figure shows a linear array, but in the disclosed embodiments, it is more beneficial to utilize a two-dimensional array so that the beam can be steered in two dimensions. The array includes radiator elements 105, each of which is connected to a phase shifter 110. Each of the phase shifters 110 may be in the form of a delay line. The phase shifters 110 are controlled by a computer C to introduce a certain amount of delay into the corresponding transmission line and thereby steer the beam by an angle Θ from the boresight.

[0032] The signal generated by the transmitter TX is input to the common feeder 115 and split and distributed to each of the radiating elements 105. Before reaching the radiating elements, the signal from the feeder passes through the corresponding phase shifters 110, and the phase of the signal changes by an individual amount in each of the delay lines, so that the beam will be steered. The phase shifters 110 can also be controlled by an on-chip processor or a baseband processor. The range of each phase shifter can be quantized by a look-up table (LUT). By quickly obtaining the phase value from the memory, the beam can be steered. Note that the reverse occurs in the case of reception.

[0033] In the example of the passive phased array or passive electronically scanned array (PESA) shown in FIG. 1, the antenna elements are phased arrays connected to a single transmitter and / or receiver. However, the disclosed embodiments are not limited to PESAs, but rather include any antenna that can be electronically steered. For example, an active phased array or active electronically scanned array (AESA) can also be used. An AESA is a phased array in which each of the antenna elements has an analog transmitter / receiver (T / R) module and performs the phase shift necessary to electronically steer the antenna beam. Also, any of the disclosed embodiments may be implemented using a digital beamforming (DBF) phased array in which each of the elements in the array has a digital receiver / exciter. Since the signals in each of the elements are digitized by the receiver / exciter, the antenna beam can be digitally formed by a field programmable gate array (FPGA) or an array computer 110. In this approach, for example, multiple simultaneous antenna beams can be formed by grouping the radiating elements into subgroups.

[0034] In addition, the present person in charge developed a phased array antenna in which a phase shifter is formed using, for example, a delay line that traverses a variable permittivity material such as liquid crystal. Such a phased array antenna is also suitable for the embodiments disclosed in this specification. Examples of such arrays are described, for example, in U.S. Patent No. 7,884,766, U.S. Patent Application Publication Nos. 2017 / 0093363, 2018 / 0159213, and 2018 / 0062272, the contents of which are hereby incorporated by reference in their entirety.

[0035] Generally, for each of the disclosed embodiments, it should be understood that each of the antennas is any electronically steerable directive antenna having a plurality of radiators similar to the example of the phased array antenna shown in FIG. 1. For the sake of simplicity, in the disclosure provided here, the term "phased array antenna" is used, but this term encompasses any electronically steerable antenna having a plurality of radiators that forms a radiation pattern that can be electronically steered It should be understood to include.

[0036] FIG. 2 shows an embodiment in which a plurality of phased array antennas are deployed for communicating with one or more satellites. The arrangement of FIG. 2 enables continuous real-time reconfiguration of the plurality of phased array antennas. In FIG. 2, the asset 200 can be any platform having a plurality of communication devices such as computers 1 to n that communicate with one or more satellites 1 to 4. The asset 200 can be, for example, an airplane, a ship, a train, or land equipment.

[0037] When the asset includes a plurality of antennas ESA1 to ESAn, they are coupled to a plurality of modems MD1 to MDn via a switching mechanism 205. Each of the antennas has a phased array whose beam shape and direction are controlled by a phase controller 220. The phase controller 220 sets the phase or time delay of the signal for each radiator of the phased array to form a main beam pointing in the desired direction. In this specification, the term phase controller is used as an abbreviation for any controller used to electronically steer the beam formed by the radiator. For example, the phase controller 220 may control the time delay of the RF signal of the same source when inputting to each radiator. In another example, the phase controller 220 may be a field programmable gate array that digitally forms an antenna beam.

[0038] In some embodiments, the phase controller 220 can maintain a database, such as a look-up table, listing all available satellites in space and their positions. In some embodiments, the phase controller 220 can also receive the GPS coordinates and other motion data of the asset 200 from the motion circuit 225 so as to determine which satellites are within the field of view of its phased array. The phase controller 220 can use this information to steer each beam of the phased array in the appropriate direction towards the satellite.

[0039] In some embodiments, the phase controller 220 includes a control port for receiving from the control circuit 215 a control signal indicating the satellite with which the antenna is to communicate. The control circuit 215 can include a data port that is functionally connected to the router 210, as a result of which the control circuit can actively make its switching decisions based on the data collected from the router 210. The data can include the available bandwidth of each antenna, the data transmission speed of each antenna, and the type of transmission (voice, video, data, etc.) required by each communication device 1 to n.

[0040] The control circuit can also be connected to each of the ESAs to obtain the RSSI from each of the ESAs. The control circuit can further be connected to the modem 255 to receive other data related to its switching decision, such as the service level assigned to each of the communication devices, the transmission cost of each satellite, etc. For example, the modem 255 can be coupled to an external data management system 260 to provide the control circuit 215 with various transmission parameters and data related to user accounts.

[0041] The phase controller uses a database to calculate the phase delay to be applied to each of the radiators so as to direct the antenna towards the direction of the designated satellite. When the asset 200 is a moving body, such as an airplane, a ship, etc., the motion circuit 225 continuously transmits a motion signal to the phase controller 220, whereby the phase controller can continuously adjust the phase to be applied to each of the radiators to keep the beam directed towards the satellite.

[0042] The plurality of aforementioned communication devices, shown here as computers 1 to n, are coupled to the modems MD1 to MDn via the router 21 0. This arrangement enables a real-time configuration of the system, allowing any communication device 1 to n to be coupled to any modem MD1 to MDn and those to be coupled to any antenna ESA1 to ESAn. Thereby, the bandwidth from available satellites can be utilized efficiently.

[0043] Multiple users on the platform may have various needs. For example, perhaps one computer is for the crew's welfare to watch Netflix (registered trademark), and another computer is for the navigation management of the ship. The control circuit 215 can determine the satellites that transmit each traffic volume and one or more antennas to be used for that specific communication. The control circuit 215 can also command the router 210 to aggregate capacity for the traffic volume or perform other Ethernet (registered trademark)-level operations in order to guarantee the highest quality, highest performance, and lowest cost across all available paths.

[0044] For example, in some embodiments, the control circuit 215 can receive data regarding the bandwidth capacity and utilization of various satellites, such as data regarding transmission priorities, for example, live signals such as voice or video calls must have a high priority while emails can be assigned a low priority, data regarding the bandwidth costs of various services available on the satellites, etc. The control circuit 215 can then determine which satellite should be used for which transmission. Also, in some embodiments, the control circuit receives a motion signal from the motion circuit 225, and as a result, the control circuit 215 can determine which satellite can be used for which antenna. In some embodiments, the control circuit 215 also stores the physical configuration of the asset 200 and its antennas in its database. For example, the asset may possibly have ESA1 on its right side, ESA2 on its left side, and ESA3 on the roof, etc. From this, the control circuit 215 can determine which part of the sky each antenna can scan. Using all this information, the control circuit 215 can provide appropriate signals to the switches and routers, make appropriate connections, and indicate to each of the phase controllers where to direct the antennas.

[0045] For illustration purposes, in FIG. 2, both antennas ESA1 and ESA2 communicate with Sat1, and Sat1 then communicates with transceiver 1. As a result, in one embodiment, since the signal from Sat1 is too weak, the necessary file cannot be transmitted with a single connection. As one possible solution, the file can be transmitted with two connections using a receive diversity combining method by ESA1 and ESA2. ESA3 communicates with Sat3, and Sat3 then communicates with transceiver 2. ESAn communicates with both satellites Sat2 and Sat4. Sat2 communicates with transceiver 2, while Sat4 communicates with transceiver n. The two signals are routed by router 230 and combined by combining computer 235.

[0046] In an example shown in FIG. 2, transceivers 1 to 3 are shown as part of a single base station 202 connected to a network 240 such as the Internet. Data storage device 245 can be accessed via network 240 or can be co-located with the base station itself. Of course, multiple base stations may be used, and the satellite can communicate with any selected base station depending on the user's needs, the performance of each base station, the available connections, etc. Also, since data storage device 245 can be accessed via network 240, if a particular user machine needs to access data storage device 245, control circuit 215 can determine which satellite and which base station are most suitable for providing that connection. Thus, in some embodiments, control circuit 215 can periodically receive transmissions accompanied by data regarding available base stations and their operating parameters. Similarly, in the case of non-geostationary satellites, control circuit 215 can periodically receive transmissions accompanied by updates regarding the position and operating parameters of the satellite.

[0047] ​Each of the transceivers of base station 202 has an antenna 204 for exchanging communication signals with one or more satellites. In the case of communication with a geostationary satellite, the antenna 204 is a simple dish fixed in the direction of the satellite or mechanically moves and points it at the desired satellite. However, for example, in order to quickly and in real-time maneuver a non-geostationary satellite or high-speed movement between different satellites, one or more antennas 204 can be a phased array disclosed herein.

[0048] In some disclosed embodiments, satellite transmission and reception can be performed via a unidirectional transmission mechanism. For example, the User Datagram Protocol (UDP) can be used for satellite transmission and reception.

[0049] FIG. 3 shows an embodiment that utilizes optical fibers for the fast and efficient management of multiple signals. Each of the phased array antennas includes electro-optical transceivers EOT1 to EOTn that convert between optical signals and electrical signals. The optical signals travel through the optical fibers indicated by the dashed arrows, which are managed by an Optical Fiber Management Unit (OFMU) 320. The OFMU 320 also includes an electro-optical modulator that converts between optical and electrical signals. The signals traveling between the OFMU 320 and the switch 205 are electrical signals and travel through a waveguide or coaxial cable, indicated by the solid arrows.

[0050] In the example shown in FIG. 3, the OFMU 320 can connect any of the phased array antennas 1 to n to any of the modems MD1 to MDn via the switch 205. Also, the Optical Fiber Management Unit 320 can sum the RF signals from a plurality of selected phased array antennas and provide the summed RF signals to the selected modem. Conversely, the Optical Fiber Management Unit 320 may split the transmission power to a plurality of selected antennas for transmission. Further, the OFMU 320 can perform other digital baseband operations to zero, beamform, or interference cancel.

[0051] Figure 3A shows a modification of the embodiment of FIG. 3. The optical fiber management unit 320 further performs the functions previously executed by the switch 205. Since the optical fiber management unit 320 can synthesize and split signals, the signals can be directed to any of the modulators MD1 to MDn, and as a result, the need for the switch 205 can be eliminated. The control circuit 215 thus transmits an instruction signal to the OFMU 320 to perform appropriate signal routing.

[0052] FIG. 4 shows an example of generating path diversity that is particularly beneficial for secure file transmission or load distribution. In the example shown in FIG. 4, the platform 400 can be any platform having one or more phased array antennas described herein, includes a computer 411, and is attempting to transmit one file F. In one example, since the data confidentiality of the file is high, it is desirable to cause a man-in-the-middle attack to fail and, even if successful, to ensure that the attacker can only obtain a portion of the data. In another example, if it is determined that the file is too large for the detected RSSI, it may be desirable to use multiple paths, with each path transmitting only a portion of the file.

[0053] As shown in FIG. 4, the computer 411 divides the file F into several parts, here three parts. Next, the control system 415 operates switches and routers (see FIG. 1) to create three transmission paths, each directed to one satellite. In the example shown in FIG. 4, since each of the satellites communicates with a different base station, each part of the file is received by a different antenna and transceiver system. This is not necessarily always the case. Alternatively, some or all of the satellites may be communicating with the same base station. In any case, the control system 415 indicates to the base station, via the configurators CFG1 to CFGn, which files to receive from which satellites, and when a portion of the files is received, indicates to the data center 422 that they should be assembled into a single file. They may be assembled and stored at the data center 422. Of course, any return response may be similarly split and transmitted over multiple paths.

[0054] Note in the example of FIG. 4 that the control system 415 is in the cloud rather than on the platform 400. Such a configuration is not limited to this particular example and may be used in any of the embodiments disclosed herein.

[0055] FIG. 5 is a flowchart showing unordered steps that the process implemented by the disclosed embodiments may take. For example, at step 500, the account data of the registered user is loaded into the control circuit 215. The account data may include data speed, data rate price, data limit, and the like. The account data can be stored in the memory of the control circuit. At step 505, satellite data can be loaded into the control circuit 215. The satellite data may include satellite ID, satellite coordinates, transmission speed, bandwidth, and the like. At step 510, movement data can be uploaded to the control circuit 215. The movement data may include movement data related to the satellite and movement data related to the platform on which the ESA is mounted. Note that all the data uploaded at steps 500, 505, and 510 may be updated periodically.

[0056] In step 515, a transmission request is received from the user. Using the information of the transmission request and the data uploaded in steps 500, 505, and 510, in step 520, an appropriate route for transmission is selected. For example, if multiple antennas are available, the transmission can be performed by multiple routes using multiple antennas, for example, using a diversity combining method. In step 525, for the antennas within the selected route, the transmission / reception intensity is verified. For example, this is done by receiving the RSSI from each unit. When the appropriate signal strength for the selected route is confirmed, the switch is set so that the selected antenna connects to the selected modem, and the router is set so that the user's machine connects to the selected modem.

[0057] FIG. 6 shows an example of an embodiment that improves the overall signal-to-noise ratio (SNR) of a received signal using multiple antennas such as a plurality of phased arrays. Improving the SNR of a received signal using multiple antennas is known in the art, but current implementations are insufficient or too complex and expensive for widespread implementation. For example, the simplest implementation is to determine which antenna provides the strongest total instantaneous signal (e.g., the highest RSSI) and select the signal of that antenna. Another fast method is to apply equal weights to each of the antennas and sum the weighted signals from all the antennas. Such an approach is fast and easy to implement, but it loses the signal quality of the best antenna, overweights weak signals, and thereby may introduce noise. For details, the reader is referred to "Comparison of SNR Estimation Techniques for AWGN Channels" by D.R. Pauluzzi and N.C. Beaulieu, published in IEEE Transactions on Wireless Communications, Vol. 48, No. 10, October 2000, available at https: / / ieeexplore.ieee.org / document / 871393. The embodiment of FIG. 6 provides an improved weighting using a new method that is fast and relatively easy to implement.

[0058] The architecture shown in FIG. 6 is called a Distributed Electronically Steerable Array (DESA). In the example of FIG. 6, since multiple arrays are used to combine the diversity reception signals, it may also be called a reception diversity combining architecture instead of a D ESA. Such an architecture is particularly beneficial when the satellite is not visible to one or more of the arrays, or when the aperture is very small due to the beam tilt angle. This is shown in FIG. 6 by considering a mobile platform 600 such as a ship where the antennas are placed at different parts of the ship. The ship moves in a direction such that the satellite is on the starboard side, and arrays x1, x2, x3 (x3 is not shown as it is, for example, at the stern) have good signals, but x4 is placed on the port side and thus cannot be steered towards the satellite, or the aperture becomes very small due to the steering angle and noise may be generated in the signal.

[0059] The modem 602 conditions signals for transmission from the Internet, such as streaming video. The signals are uploaded from the base station 604 to the satellite SAT1, and the satellite SAT1 broadcasts it towards the Earth. Some or all of the antennas x1 - x4 pick up the signals, and each may have an individual SNR due to various factors such as propagation loss, meteorology, polarization mismatch, interference, and the physical orientation of the array. Next, the signals from the arrays are processed by the DESA processing unit 640 to generate a digital signal provided to the modem 648, and the modem 648 transmits the signal to various user devices. The DESA processing unit 640 includes an RF transceiver 642 that receives and digitizes the signals from the antennas, and a digital signal processor 644 that determines the weights to be applied to the signals from each of the antennas and sums the weighted signals. The DESA processing unit 640 also includes an antenna array module AIM646, which is a controller responsible for the steering, geolocation, and system management of the phased array antenna. AIM646 has a structure similar to that described for the phase controller 220 in FIG. 2 and can provide similar operations and functions.

[0060] FIG. 7 shows an example of an embodiment of a received signal path that can be used in a receive diversity combining architecture as shown in the example of FIG. 6. In the example of FIG. 7, it includes the same number of channels as the antennas, and only the first and last channels are shown in detail, while the remaining channels are all the same and thus shown by ellipsis. Since the disclosed method is not limited to a frequency band, it can be applied to any frequency band. Each of the antennas receives a satellite signal, and in this example, as shown, the transmission is performed in the Ka or Ku band. After passing through an RF filter, the signal is input to a standard low-noise block (LNB), and the LNB down-converts the signal to an intermediate frequency within the L band. After passing through an intermediate frequency filter, the signal is amplified and converted to a digital signal by an RF ADC converter. Next, the digital signal processor DSP644 applies the calculated weights to each of the channels and sums the signals from all the channels.

[0061] FIG. 8 shows an example of a digital signal processor that can be employed in a receive diversity combining architecture according to the embodiments disclosed herein. Due to path differences and other atmospheric effects, it is necessary to synchronize and calibrate the signals of the channels so that they match each other. In the embodiment of FIG. 8, this is first done by a channel scanner 850 that compares the correlation of each channel with the remaining channels to determine the channel with the highest fidelity. Essentially, the channel scanner examines the channels and selects the most reliable channel as the golden reference channel. The golden reference channel is used by a time synchronizer 860 to estimate the time shift required to time-align all the channels. In one example, for each of the received channels RxN, the time synchronizer 860 upsamples the signal to achieve the desired fractional sample accuracy. Next, the cross-correlation of the received channel with the golden reference channel is determined. Next, the maximum coefficient value is set as the path delay difference and used to align the received channel RxN with the golden reference channel.

[0062] Similarly, the golden reference channel is used by the phase calibration module 862 to estimate the phase shifts necessary to align all channels. In one example, for each of the receive channels RxN, the phase calibration module 862 calculates the average value of the phase difference between the receive channel RxN and the golden reference channel. Next, the average phase error value is applied to the receive channel RxN.

[0063] As described above, the channel scanner 850 ranks the channels according to their relative fidelity or reliability. This is done first by the cross-correlation module 854 deriving a cross-correlation matrix. The result of the cross-correlation is used by the ranking module 856 to generate a ranked order of the channels, referred to herein as level 1 ranking, and to select the golden reference channel. The level 1 signals are provided to the rank controller 870.

[0064] In this regard, the cross-correlation matrix is derived as follows. JPEG2025094113000002.jpg21105Here, m≠n, ns is the integration length, and nd is the delay search window. For an N-channel receiver, the equation generates the number of cross-correlation coefficients of d. JPEG2025094113000003.jpg21105d is an integer and relates to the triangular components of the following square matrix. JPEG2025094113000004.jpg48105For example, when N = 4, the equation generates an array of six coefficients. JPEG2025094113000005.jpg27105

[0065] The coefficients obtained from the matrix are used for the determination of level 1 ranking. A Q matrix consisting of dimensions of N rows and (N - 1) columns is defined, and the data of each channel is used exactly (N - 1) times from the cross-correlation matrix calculation. The correlation sum (CS) associated with each nth channel is calculated by adding all the row elements of Q and is given as follows. JPEG2025094113000006.jpg2075

[0066] For the case of N = 4, the formula is as follows. JPEG2025094113000007.jpg29156

[0067] Select the golden reference channel based on the highest value of the score defined by the following set. JPEG2025094113000008.jpg35130 Here, φ is a gain function including a normalization scale. In the case of the same score, one of the channels with the same score is selected, or in this embodiment, the result of the level 2 ranking determination can be used to select the golden reference channel with higher accuracy.

[0068] Referring back to FIG. 8, the channel scanner 850 includes a peak-to-average power module 852 and calculates a level 2 ranking based on the peak-to-average power ratio (PAPR). The level 2 signal is input to the rank controller 870, and the score of the channel is generated using the determinations at levels 1 and 2. The score is provided to the weighting module 864, the weights assigned to each of the channels are applied, and the weighted signals of all the channels are synthesized by the diversity synthesizer 866. Incidentally, as shown in the example of FIG. 8, an optional external input port is provided so that the user can disable the selection of the rank controller or provide other commands to the rank controller 870. The determination of the level 2 ranking is based on the calculation of the PAPR using the following formula. JPEG2025094113000009.jpg3179 In this example, the peak power is less than 100% of the square of the maximum amplitude, for example, max{|x| 2} is , corresponding to the 99% PAPR of the K - sample collection window. Using 99% PAPR can avoid unrealistic peaks due to system errors, glitches, or sampling errors. When the PAPR is high, the radio propagation channel deteriorates and the Eb / N0 decreases (energy per bit to noise power spectral density ratio, or normalized signal - to - noise ratio (SNR) measurement, also called "SNR per bit").

[0069] Ideally, the level - 1 CS maximum value and the level - 2 PAPR minimum value should correspond to the same receiving channel. The reference channel selection can be calculated by the following combined score. JPEG2025094113000010.jpg19132

[0070] Generally, the scoring method can use several decision variables based on multiple physical quantities. As described above, in the example of Figure 8, the sum of cross - correlations is used for level - 1 ranking and PAPR is used for level - 2 ranking. By using another decision variable, PAPR, the true channel SNR can be approximated more appropriately, so that it is possible to approach the optimal composite solution. Furthermore, other variables such as the total signal plus noise power (Psig) can also be used. Therefore, a general description for determining the score of the n - th channel of N multiple Rx channels can be expressed as follows. JPEG2025094113000011.jpg33126Here, SCORE = [SCORE1, SCORE2, ..., SCORE N is an N - dimensional array, Q is the total number of decision variables, φ is a gain function for normalization, and θ is a scalar function. Ideally, the level - 1 CS maximum value and the level - 2 PAPR minimum value should correspond to the same receiving channel. The reference channel selection can be calculated by the combined score for approximating the true channel state more appropriately. JPEG2025094113000012.jpg22126Here, n is the channel number that gives the highest score.

[0071] For the channels with Q = 2 (Level 1 ranking and Level 2 ranking) and N = 4, which is an example of FIG. 8, the formula for obtaining the score is as follows. JPEG2025094113000013.jpg20142 This score is the value used for the weighting coefficients of the weighting module 864. Channels with better conditions and higher quality are exponentially weighted more, and a higher SNR is shown at the output of the diversity synthesizer 866.

[0072] According to the provided disclosure, a method for synthesizing transmitted signals received by a plurality of antennas is disclosed. The method calculates the cross-correlation coefficients of the signals obtained from each of the plurality of antennas described above, selects the signal that generates the highest coefficient as the golden reference signal, uses the golden reference signal to time-synchronize the transmitted signals received by the plurality of antennas, derives the peak power to average power ratio for each of the transmitted signals received by the plurality of antennas, uses the cross-correlation coefficients and the peak power to average power ratio described above to generate weighting coefficients for each of the transmitted signals received by the plurality of antennas, applies the weighting coefficients to each of the transmitted signals received by the plurality of antennas to generate a plurality of weighted signals, and sums the plurality of weighted signals described above. As described above, the method may further include calibrating the phases of the transmitted signals received by the plurality of antennas using the golden reference signal.

[0073] A system for receiving transmitted signals is provided. The system described above includes a plurality of antennas each receiving a received signal, and a plurality according to the quality of the received signal of each of the plurality of antennas A ranking module that ranks the antennas, generates corresponding level 1 signals, and selects the highest-ranked antenna as the golden reference signal; a synchronizer that synchronizes all received signals of the plurality of antennas using the golden reference signal; a level 2 module that calculates the peak-to-average power ratio for each of the received signals of the plurality of antennas and generates corresponding level 2 signals; a scoring unit that generates a weighted score for each of the received signals of the plurality of antennas using the aforementioned level 1 signals and level 2 signals; a weighting module that applies the aforementioned weighted score to each of the corresponding received signals for each of the plurality of antennas to generate a plurality of weighted signals; and a summing module that synthesizes all of the aforementioned weighted signals.

[0074] FIG. 2A shows an example of an embodiment for satellite communication and realizes receive diversity combining to improve the overall SNR. The embodiment of FIG. 2A is similar to the embodiment shown in FIG. 2 and thus will not be described in detail. The embodiment of FIG. 2A shows how the DESA elements of FIGS. 7 and 8 can be incorporated into the architecture of FIG. 2 and thus enables receive diversity combining and can improve the overall SNR.

[0075] Similarly, FIG. 3B shows an example of an embodiment for satellite communication, realizes receive diversity combining to improve the overall SNR, and incorporates optical fibers. The embodiment of FIG. 3B is similar to the embodiment shown in FIG. 3 and thus will not be described in detail. The embodiment of FIG. 3B shows how the DESA elements of FIGS. 7 and 8 can be incorporated into the architecture of FIG. 3 and thus enables receive diversity combining and can improve the overall SNR.

[0076] FIG. 5A shows a flowchart of an unordered procedure that can be taken to perform a diversity reception combining operation to improve the overall SNR. In step 540, a signal is received with a plurality of antennas that may include, for example, a cellular antenna, a wireless LAN (WiFi) antenna, an array antenna, etc. Even though the data of the signals received by the antennas is the same, the quality of the signals received by each of the antennas may not be the same, so different SNRs or RSSIs may occur for each of the channels. The method proceeds to generate a weighted sum of the signals in order to improve the overall SNR, as follows. The method generates two ranked signals, a level 1 ranked signal and a level 2 ranked signal. The level 1 ranked signal is generated in step 545 by obtaining the cross-correlation coefficients of the signals from the plurality of channels. The ranking arranges the highest coefficient as the best signal and the lowest coefficient as the worst channel. Also, in step 550, the best channel (highest coefficient) is selected as the golden reference signal. The level 2 ranked signal is generated in step 555 by calculating the PAPR of each channel. The ranking arranges the lowest PAPR as the best signal and the highest PAPR as the worst channel.

[0077] In step 560, the golden reference signal is used to synchronize the channels in the time domain. In step 565, the golden reference signal is used to calibrate the phases of all the channels. In step 570, weights are generated using the level 1 ranking and the level 2 ranking, and then the signals of each channel are weighted by the corresponding weights. In step 575, the weighted signals of the channels are added together.

[0078] It should be understood that the processes and techniques described in this specification are not inherently related to any particular apparatus and can be implemented by any suitable combination of components. Furthermore, in accordance with the teachings described in this specification, various types of general-purpose apparatuses can be used. Although the present invention has been described with reference to specific examples, it is intended to be illustrative rather than limiting in every respect. Those skilled in the art will understand that many different combinations are suitable for implementing the present invention.

[0079] Also, for other implementations of the present invention, it will be apparent to those skilled in the art upon consideration of the specification and implementations of the present invention disclosed herein. The various aspects and / or components of the described embodiments can be used alone or in any combination. This specification and the examples are to be regarded as merely illustrative, and the true scope and spirit of the present invention are indicated by the following claims.

Claims

1. a plurality of antennas, each of which includes a phased array radiator; A plurality of modems; a switch for dynamically coupling any of said antennas to any of said modems; A plurality of communication devices; a router for dynamically coupling any of said communication devices to any of said modems; a controller for controlling the switches and routers to provide real-time instructions for connecting the plurality of antennas, the plurality of modems, and the plurality of communication devices; A satellite communication antenna system including:

2. 2. The antenna system of claim 1, wherein each of the plurality of antennas includes one of a plurality of delay lines each coupled to one of the phased array radiators, or a plurality of active beamforming chips corresponding to the phased array radiators.

3. each of the plurality of antennas includes a plurality of delay lines, each of the delay lines being coupled to one of the phased array radiators; 3. The antenna system of claim 2, wherein each of said delay lines traverses a variable dielectric constant material.

4. 4. The antenna system of claim 3, wherein each of said antennas further comprises a phase controller that controls the amount of delay introduced by each of said delay lines.

5. 10. The antenna system of claim 1, wherein each of said antennas further comprises a phase controller, said phase controller including a database storing a list of all available satellites in the sky and their positions.

6. 6. The antenna system of claim 5, further comprising a motion circuit that provides motion data to at least one of said controller and said phase controller.

7. 6. The antenna system of claim 5, wherein said phase controller includes a control port for receiving a control signal from said controller indicating with which satellite said antenna should communicate.

8. the controller includes a data port operatively connected to the router; The antenna system of claim 5 , wherein the controller actively makes switching decisions based on data collected from the routers.

9. The antenna system further comprises: a plurality of electro-optical transceivers, each coupled to one of the antennas; an optical fiber management unit; a plurality of fiber optic lines coupling each of the electro-optic transceivers to the fiber optic management unit; The system of claim 1 , comprising:

10. A system mounted on a mobile platform for satellite communications, comprising: a plurality of phased array antennas, each having a plurality of radiators and a plurality of phase shifters, each of which introduces a delay into an RF signal propagating therethrough; at least one phase controller that operates the phase shifter to introduce the delay into the RF signal; A plurality of modems; a switch operable to connect any of said modems to any of said phased array antennas in real time as determined; A communication device; a router operable to route signals between any of said modems and said communication devices; a control circuit that provides real-time instructions to the switch that forms a connection between the modem and any of the phased array antennas, and to the router that routes signals between the modem and any of the communication devices; A system including:

11. moreover, a movement indicator for providing a movement signal to the control circuitry indicative of a movement of the mobile platform; The system of claim 10 , comprising:

12. The system of claim 11 , wherein the movement indicator includes a Global Positioning System receiver.

13. 11. The system of claim 10, wherein each of the phase shifters includes one of a delay line across a variable dielectric constant material or an active beam forming chip.

14. 11. The system of claim 10, wherein each of the phase shifters includes a delay line across a variable dielectric constant material and includes a control line that receives a potential signal from the phase controller.

15. moreover, a plurality of electro-optical transceivers, each coupled to one of the antennas; an optical fiber management unit; a plurality of optical fiber lines coupling each of said electro-optical transceivers to said optical fiber management unit; The system of claim 10 , comprising:

16. The system of claim 10 , wherein the phase controller comprises a database that stores a list of all available satellites in the sky and their positions.

17. 1. A method for controlling communications between a plurality of phased array antennas and a plurality of satellites, comprising: receiving an indication from the computer device of the data to be transmitted to the satellite; Determine which satellites are available for communication, directing the phased array antenna to point toward a selected satellite; receiving a received signal strength (RSSI) signal from the phased array antenna; selecting a transmitting phased array antenna based on the RSSI signal; connecting said transmitting phased array antenna to a selected modulator; operating a router to connect said modulator to said computing device; starting transmission of the data to be transmitted.

18. 20. The method of claim 17, further comprising the acts of receiving account data corresponding to the computing device and selecting a transmission path responsive to the account data.

19. moreover, 20. The method of claim 17, comprising an act of receiving motion data of a platform supporting the phased array antenna and determining which of the plurality of phased array antennas is capable of communicating with the selected satellite based on the motion data.

20. 20. The method of claim 17, wherein the act of connecting the transmitting phased array antenna to the selected modulator comprises an act of operating a switch operable to connect any of the plurality of phased array antennas to any available modulator.

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