THERMAL LOAD BALANCING FOR ELECTRONICALLY STEERABLE ANTENNAS

Example embodiments disclosed herein relate to optimizing operation of an electronically steerable antenna (ESA) with respect to temperature-related constraints. Thermal load experienced by individual antenna elements or tiles of the ESA is balanced to maximize an expected time before the ESA reaches a shutdown temperature. An example method includes determining a reduced number of antenna tiles that minimally satisfies a signal quality requirement with respect to a target system. The method further includes selecting an optimized sequence of tile patterns of the reduced number of antenna tiles within the ESA. The optimized sequence corresponds to an optimized path that traverses a graph having nodes corresponding to the tile patterns and edges defining a count of shared tiles between respective tile patterns. The method further includes operating the ESA according to the optimized sequence of tile patterns based on activating specific tiles identified by each pattern in a sequential manner.

TECHNICAL FIELD

This document relates to antenna technology deployable on a commercial passenger vehicle.

BACKGROUND

Antenna systems may be deployed on commercial passenger vehicles to provide communication capabilities with other extra-vehicular systems. As a commercial passenger vehicle and an extra-vehicle system, such as a low earth orbit (LEO) satellite, are in movement relative to one another, operation of the vehicle's antenna system to maintain communications therebetween is resource- and power-intensive. Improvements to antenna technology are needed to extend antenna-based vehicular communication capabilities.

SUMMARY

This document is related to operation of electronically controlled antenna arrays, and in particular, electronically steerable antennas (ESAs). In some embodiments, this document provides improvements to the operation of ESAs used by commercial passenger vehicles, including airplanes and others. While this document describes various embodiments in the context of ESAs, it will be understood that certain concepts and embodiments may be applicable to other antennas understood under other terminology, such as phased arrays, electronically scanned arrays, beam steering antennas, and/or the like.

In particular, the present document provides various techniques for balancing thermal load on antenna tiles of an electronically steerable antenna (ESA). According to example embodiments disclosed herein, only a subset of the antenna elements or antenna tiles of an ESA are activated and used at any time instance. An activated subset of antenna elements/tiles can manifest as a spatial pattern across the ESA, and periodically, different patterns of antenna elements/tiles are activated. Consecutive element/tile patterns may share common tiles, and the patterns are selected to minimize a number of common tiles between the consecutive element/tile patterns. In doing so, any given tile is given a maximized time to cool before being activated. Accordingly, embodiments disclosed herein provide technical improvements to antenna array operation, by optimizing cooling time for each individual antenna element or tile.

In one example aspect, a method of thermal load balancing for an ESA of a vehicle is disclosed. The ESA includes a total N number of antenna tiles. The method includes determining, by an antenna controller, a particular M number of antenna tiles for transmitting or receiving at least one communication signal via the ESA to or from a communications satellite, respectively. The particular M number of antenna tiles is less than the total N number of antenna tiles. The method further includes selecting, by the antenna controller, an optimized sequence of unique tile patterns of the particular M number of antenna tiles. That is, each unique tile pattern contains M out of the total N number of tiles. The optimized sequence corresponds to an optimized path that traverses a graph having (i) nodes corresponding to the unique tile patterns, and (ii) edges that define a count of shared tiles between different unique tile patterns. The optimized path minimizes the count of shared tiles (as defined by the graph edges) between consecutive tile patterns in the optimized path.

The method further includes operating, by the antenna controller, the ESA according to the optimized sequence of unique tile patterns to transmit or receive at least one communication signal via the ESA. For example, the antenna controller activates specific M tiles identified by a first tile pattern for a first time period, and then the antenna controller activates specific M tiles identified by a second tile pattern of the optimized sequence for a second time period subsequent to the first time period. As a result, a given tile identified by the first tile pattern and not identified by the second tile pattern is given time to rest and cool while the ESA is operated according to the second tile pattern.

In another example aspect, a method of optimizing operation of an antenna array that includes a number of antenna elements arranged adjacently is disclosed. The method includes determining a reduced number of antenna elements that minimally satisfies a signal quality requirement with respect to a target system. The method further includes selecting a sequence of element arrangements each identifying a different permutation of the reduced number of antenna elements within the antenna array. The sequence minimizes a count of common antenna elements between consecutive arrangements in order to maximize a non-operational time for a given antenna element. The method further includes coordinating operation of the antenna elements of the antenna array based on the element arrangements in accordance with the sequence.

In another example aspect, an antenna system for a vehicle is disclosed. The antenna system includes an ESA that includes antenna tiles operable in connection with one another to emit and/or receive directed communication signals. The antenna system further includes an antenna controller device that includes a processor. The processor executes instructions to cause the antenna controller device to determine a reduced number of antenna tiles of the ESA. The processor executes instructions to cause the antenna controller device to further select a sequence of patterns of the reduced number of antenna tiles that minimizes a count of common tiles between consecutive patterns in the sequence to allow for ambient cooling of the antenna tiles of the ESA. The processor executes instructions to cause the antenna controller device to further determine a dwelling time for each pattern of the sequence. The dwelling time defines a duration in which the ESA is operated according to a respective pattern. The processor executes instructions to cause the antenna controller device to further operate the reduced number of antenna tiles of the ESA according to the sequence of patterns and the dwelling time for each pattern to emit or receive a given directed communication signal.

In yet another aspect, a computer readable medium is disclosed. The computer readable medium stores processor-executable program code that, upon execution by one or more processors, causes implementation of a method described in the present document.

These, and other aspects are disclosed throughout the present document.

DETAILED DESCRIPTION

Antenna arrays that include multiple antenna elements may be used to support communications between commercial passenger vehicles and low earth orbit (LEO) satellite constellations. An antenna array, for example embodied as an electronically steerable antenna (ESA), can point in different directions without physically re-orienting or moving the antenna array itself. As a result, communication with LEO satellites and other terminals exhibiting mobility relative to an ESA, for example, can be maintained with reduced interruptions.

A characteristic of ESAs and similar antenna systems (e.g., phased arrays, electronically scanned arrays) is that they consume significant power and produce significant heat. When the antenna's temperature reaches its operating limits via continued use, the antenna can suffer permanent damage. An antenna's temperature more quickly reaches these temperature limits when located in particularly hot ambient environments. These temperature constraints present a technical challenge in the way of effective use of ESAs and similar antenna arrays.

According to example embodiments, the present disclosure provides solutions in which thermal load experienced by antenna elements or tiles of an antenna array is optimized, such that the antenna array can be operated for longer continuous time periods. The technical solutions provided by the present disclosure may improve antenna operations in hot ambient environments, in particular. For example, an aircraft having an antenna array and being grounded at an airport in a desert environment may be able to operate the antenna array for longer periods of time in accordance with the disclosed embodiments being implemented. A commercial passenger aircraft may then be capable of satisfying gate-to-gate connectivity requirements.

In order to optimize the thermal load experienced by antenna elements or tiles, example embodiments involve the selection of an optimized sequence of element/tile patterns for antenna array. Each pattern identifies specific individual antenna elements or tiles to be activated at a given time, and each pattern of the optimized sequence identifies a different and unique permutation of specific antenna elements/tiles. According to example embodiments, the sequence of patterns is optimized to minimize a number of common tiles between consecutive patterns in the sequence. By this optimization, any given tile has a maximized time to rest and cool, and overall, the expected time for the antenna array to reach a shutdown temperature is maximized.

In some embodiments, the sequence of patterns is determined based on a graph path optimization technique. In particular, a graph may be defined to include nodes corresponding to different element/tile patterns and edges that define the number of common tiles between respective patterns. A complete path through the graph that minimizes the “distance” traversed via the edges then represents the optimized sequence of element/tile patterns that minimizes common tiles between consecutive element/tile patterns and maximizes cooling time for individual elements/tiles. In some embodiments, optimized graph paths may be pre-determined and retrieved to operate an antenna array in a reduced service mode on demand. Further to selecting an optimized sequence of element/tile patterns, example embodiments include determining a dwelling time for each pattern of the optimized sequence. The dwelling time defines the amount of time that the specific elements/tiles identified by a given pattern are activated before specific elements/tiles identified by another pattern are subsequently activated. Thus, in some embodiments, the optimized sequence and dwelling times define a mode of improved operation for the antenna array.

Thus, disclosed embodiments provide a dynamic power loading scheme for an antenna array that involves opportunistic switching of element/tile patterns, thereby maximizing cooling of inactive elements/tiles. Example embodiments disclosed herein may be applied to transmission and reception operations for an antenna array, and may be applied to each of a transmit aperture and a receive aperture. Example embodiments enable aircraft in-flight connectivity systems to provide communication services even in thermally challenging environments. While various embodiments disclosed herein may be discussed in the context of an aircraft that includes one or more antenna systems, it will be appreciated that disclosed concepts are generally applicable to other antenna systems in other (e.g., non-aircraft, non-vehicular) applications, environments, and implementations.

Referring now toFIG.1A, an example of a vehicle102configured for extra-vehicular communications via one or more antenna systems104is illustrated. In some embodiments, the vehicle102and the one or more antenna systems104implement example thermal load balancing techniques disclosed herein in order for the vehicle102to maintain longer connectivity with other systems in thermally challenging environments. In the example, the vehicle is a commercial passenger vehicle, and specifically an aircraft.

In some embodiments, the one or more antenna systems104provide connectivity to extra-vehicular systems for in-vehicle systems, including one or more servers106, one or more databases108, and one or more passenger devices110. For example, via the one or more antenna systems104, the server106and/or the passenger devices110may communicate with one or more satellites112(e.g., LEO satellites, geostationary satellites), a constellation or network of satellites112, cell towers114or nodes of a cellular network, ground stations116, other antennas (e.g., extra-vehicular antennas120), and/or the like. For example, ground stations116may include access points for local area networks (e.g., Wi-Fi) located at airport gates, ground control towers, ground-based databases118or data servers, other vehicles102located on the ground, and/or the like. In some example, one or more extra-vehicular antennas120and/or cell towers114communicate or interface with the antenna system104of the vehicle102, such that other computer(s), such as ground station116and other databases118, that are connected to the extra-vehicular antennas120and/or cell towers114(e.g., via the Internet, via a cellular network) can transmit and receive data with the server106and other in-vehicle systems. That is, the extra-vehicular antennas120and/or cell towers114may act as communication nodes between the antenna systems104of the vehicle102and ground stations116and other databases118. Data provided to in-vehicle systems (e.g., server106) from ground station116and other databases118can include data and information related to passengers, airlines or groups (e.g., fleets) of vehicles, weather, and/or the like. Generally, an antenna system104may bridge an in-vehicle network (e.g., including server106, database108, and passenger devices110) to other networks. Accordingly, the antenna systems104of a vehicle102enable the vehicle102to communicate via these other extra-vehicular networks with other vehicles, ground stations116or servers, and/or the like. In some embodiments, the extra-vehicular antennas120are also antenna arrays, and the disclosed technology are applicable and implemented at one or both of the antenna systems104and the extra-vehicular antennas120.

In some embodiments, the vehicle102includes an antenna system104corresponding to each extra-vehicular network. For example, the vehicle102may include a first antenna system used for communicating with a network of satellites112, a second antenna system used for communicating with a cellular or telecommunications network, a third antenna system for communicating with a local area wireless network (e.g., a Wi-Fi network), and/or the like. While the illustrated example demonstrates that the vehicle102may communicate via network connections, the antenna systems104also enable the vehicle102to form direct communication links with other vehicles and ground stations116or servers.

As illustrated, the vehicle102includes a server106located within the vehicle102, and the server106may communicate with other systems located outside of the vehicle102via the antenna systems104. In some embodiments, the server106routes connections provided by the antenna systems104to other in-vehicle systems and devices, including passenger devices110. For example, the server106implements a router for the antenna systems104. In some embodiments, the server106implements various functionality disclosed herein to improve thermal load balancing of the antenna systems104. In particular, the server106may be recruited to perform example operations related to optimizing graph paths and determining a minimum number of antenna tiles/elements to activate. In some embodiments, the server106cooperates with one or more databases108to implement various embodiments disclosed herein. For example, the server106pre-determines and stores a plurality of pattern sequences for antenna operation in the databases108, such that a particular pre-determined pattern sequence may be retrieved and provided to an antenna system104for operation. As another example, the server106receives, via an antenna system104, a plurality of pre-determined pattern sequences for antenna operation (e.g., pre-determined by a ground station or server), and stores the pre-determined pattern sequences in the databases108for later on-demand use by the antenna systems104. As yet another example, the server106stores various telemetry and data logs that describe temperatures and usages of the antenna systems104for analytical operations.

In some embodiments, the server106is communicably coupled with the one or more passenger devices110, for example, via wired and/or wireless connections. In some embodiments, the vehicle102includes one or more wireless access points with which the server106is communicably coupled, and the server106implements an in-flight entertainment and communication (IFEC) installation with which passenger devices110may interface.

FIG.1Billustrates an example of an antenna system104. As illustrated, the antenna system104may include an antenna panel152and an antenna controller154that operates the antenna panel152. The antenna panel152includes a plurality of antenna elements that each transmit or receive radio frequency waves and may coordinate together to transmit or receive communication signals. Each of the antenna elements may be any one of monopole antennas, dipole antennas, loop antennas, aperture antennas, and/or the like. In some embodiments, the antenna elements of the antenna panel152are identical to one another.

In some embodiments, subsets of antenna elements are assigned to antenna tiles156, which form individual and discrete operable units of the antenna panel152. In the illustrated example, the antenna panel152includes six antenna tiles, and each antenna tile156may include a plurality of individual antenna elements (e.g., ten to a hundred elements, a hundred to five-hundred elements, a hundred to a thousand elements). In some embodiments, the antenna panel152may have four antenna tiles, six antenna tiles, nine antenna tiles, twelve antenna tiles, fourteen antenna tiles, or sixteen antenna tiles. In some embodiments, the antenna tiles156of the antenna panel152are assigned dynamically and in real-time. For example, for a given flight or mission of a vehicle or for a particular environment, the antenna controller154may determine that a total number of antenna tiles156should be six, and the antenna controller154may assign and group individual antenna elements into six antenna tiles.

As shown, the antenna tiles156(and the antenna elements therein) form a spatial arrangement spanning across the antenna panel152. In the illustrated example, the antenna tiles156are arranged in a two-by-three arrangement; however, it will be understood that antenna tiles156and different numbers thereof may be arranged in different spatial and geometric arrangements.

In some embodiments, the antenna system104includes a transmission (TX) aperture and a receive (RX) aperture, with the TX aperture being used to transmit outgoing signals and the RX aperture being used to transmit incoming signals. The TX aperture and the RX aperture may be independently controlled and operated by the antenna controller154. In some embodiments, the TX aperture and the RX aperture are located in separate antenna panels; for example, the antenna system104includes two or more antenna panels152. In some embodiments, the TX aperture and the RX aperture are located in different and separate regions of a given antenna panel.

The antenna panel152(and generally, the antenna system104as a whole) may be associated with one or more shutdown temperatures that define thermal temperatures (i.e., a physical temperature) at which the operation and capabilities of the antenna panel152with respect to transmitting and receiving signals is detrimentally affected. For example, the antenna panel152and antenna elements thereof may suffer permanent damage when operated and activated at the shutdown temperatures. As another example, the antenna panel152reaching the shutdown temperature may result in unacceptable noise (e.g., with respect to a pre-defined signal quality requirement) appearing in signals being transmitted and/or received via the antenna panel152. In some embodiments, each antenna tile156of the antenna panel152is associated with a respective shutdown temperature that is individually monitored. In some embodiments, the antenna panel152as a whole is associated with one shutdown temperature that is monitored. The shutdown temperature(s) of the antenna panel152may correlate with physical properties of the antenna elements of the antenna panel152, for example, a base electrical resistance of each element, a width and/or length of conductive wires in each element, a physical material of which each element is constructed, and/or the like.

In some embodiments, the antenna system104further includes one or more temperature sensors that are configured to measure temperatures of the antenna panel152and provide temperature data to the antenna controller154. Via the temperature data provided by the temperature sensors, the antenna controller154may implement various techniques disclosed herein to balance thermal load experienced by the antenna panel152in real-time and/or dynamically. For example, based on real-time temperature data received from the temperature sensors, the antenna controller154causes the ESA to hop between different power modes (each having a unique pattern of activated tiles).

In some embodiments, the antenna controller154is configured to operate the antenna panel152based on activating electrical power to antenna tiles156of the antenna panel152. In some embodiments, the antenna controller154is configured to selectively activate power to certain antenna tiles156of the antenna panel152without activating power to other antenna tiles156of the antenna panel152. In some embodiments, the antenna controller154further implements a modem that processes raw signals received by the antenna panel152and that generates raw signals to be emitted by the antenna panel152. In doing so, the antenna controller154may be configured to selectively apply phase offsets to different antenna tiles156to “steer” or direct an emitted signal and/or to receive a steered or directed signal.

In some embodiments, the antenna panel152is an ESA, and the antenna tiles156are operated to electronically steer the ESA. While the following description in this document may refer to ESAs and tiles of an ESA, it will be appreciated that the disclosed concepts are applicable to antenna arrays and elements of an antenna array, generally.

FIG.2illustrates an example of a computing device200that implements various embodiments disclosed herein. According to example implementations, the computing device200may embody the antenna controller154of an antenna system104and/or a server106of a vehicle102. For example, the computing device200performs various example operations to select an optimized sequence of tile patterns, determine a dwelling time for specific patterns in the optimized sequence, and operate an antenna panel according to optimized sequence and dwelling times.

InFIG.2, the device200includes at least one processor202and a memory204having instructions stored thereupon. The memory204may store instructions to be executed by the processor202. In other embodiments, additional, fewer, and/or different elements may be used to configure the device200. The memory204is an electronic holding place or storage for information or instructions so that the information or instructions can be accessed by the processor202. The memory204can include, but is not limited to, any type of random-access memory (RAM), any type of read-only memory (ROM), any type of flash memory, etc. Such as magnetic storage devices (e.g., hard disk, floppy disk, magnetic strips, etc.), optical disks (e.g., compact disk (CD), digital versatile discs (DVD), etc.), smart cards, flash memory devices, etc. The instructions upon execution by the processor202configure the device200to perform the example operations described in this patent document.

The instructions executed by the processor202may be carried out by a special purpose computer, logic circuits, or hardware circuits. The processor202may be implemented in hardware, firmware, software, or any combination thereof. The term “execution” is, for example, the process of running an application or the carrying out of the operation called for by an instruction. The instructions may be written using one or more programming language, scripting language, assembly language, etc. By executing the instruction, the processor202can perform the operations called for by that instruction. The processor202operably couples with the memory204and transceiver206to receive, to send, and to process information and to control the operations of the device200. The processor202may retrieve a set of instructions from a permanent memory device such as a ROM device and copy the instructions in an executable form to a temporary memory device that is generally some form of RAM. In some implementations, the device200can include a plurality of processors that use the same or a different processing technology.

The transceiver206transmits and receives information or data to another device (e.g., a server106, passenger devices110, an antenna controller154). For example, the transceiver206provides demodulated signals received via the antenna system104to the server106and/or passenger devices110and receives raw signals to be sent via the antenna system104. The transceiver206may be comprised of a transmitter and a receiver; in some embodiments, the device200comprises a transmitter and a receiver that are separate from another but functionally form a transceiver. In some embodiments, the computing device200(and/or the transceiver206) implements a network router or switch that connects multiple devices to the antenna system104, such that external communication capability is provided to the multiple devices.

As illustrated, the computing device200further includes an optimization module208. In some embodiments, the optimization module208is embodied by a combination of at least a portion of the processor202and the memory204. In some embodiments, the optimization module208includes a dedicated processor and a dedicated memory. In some embodiments, the optimization module208is a computing device that is included in or connected to the computing device200. The optimization module208is configured to perform (or cause the computing device200to perform) example operations disclosed herein for optimizing ESA operation and balancing thermal load experienced by an ESA. In particular, the optimization module208may be configured to construct graph structures relating different patterns of antenna tiles156, determine optimized paths through said graph structures, determine optimal dwelling times for certain tile patterns in a sequence of tile patterns, and/or the like. In order to implement optimization techniques, the optimization module208may cooperate with other components of the computing device200and/or other systems/devices to obtain current temperature data of an ESA, obtain communication channel information, and/or the like. Thus, the optimization module208is configured for various optimization techniques that are implemented by technical solutions disclosed herein.

Turning now toFIGS.3A-3C, optimization techniques performed by the optimization module208for thermal load balancing an ESA are demonstrated. According to example embodiments, the demonstrated optimization techniques may be performed to select an optimized sequence for powering specific antenna tiles156of an ESA in a manner that maximizes expected time for the ESA to reach shutdown temperature. For ease of description, the following description is provided with respect to a transmission chain via the ESA; however, it will be understood that the disclosed concepts are applicable to the receive chain of the ESA.

Thermal load balancing according to example embodiments may be performed according to a reduced service mode being set for the ESA, and the optimization module208may perform the following operations for the reduced service mode. In some embodiments, the reduced service mode is a mode of operation for the ESA in which thermal load balancing is implemented, and the reduced service mode may be set based on a determination that thermal load balancing is necessary. For example, the reduced service mode may be set in response to a determination that an ambient temperature of an environment in which the ESA is located has exceed a pre-defined threshold, and that the ESA is at risk of quickly reaching its shutdown temperature without thermal load balancing being performed.

In some embodiments, the optimization module208determines a minimum number of antenna tiles to be powered to meet a target signal-to-noise ratio (SNR). The minimum number of antenna tiles is dependent at least in part on a relative location of a target system (e.g., a LEO satellite). For example, the minimum number of antenna tiles may be lower when communicating with a target system that is normal to a planar area or surface of the ESA, while the minimum number of antenna tiles may be higher for a target system that is near the horizon with respect to the planar area or surface of the ESA. Accordingly, in some embodiments, the optimization module208is configured to obtain position information for a target system to determine the minimum or reduced number of antenna tiles. In some embodiments, the minimum number of antenna tiles is determined based on at least one of a transmit power requirement or a receive power requirement, said requirements corresponding to the target SNR.

FIG.3Aillustrates an example of an ESA300that includes a total N number of tiles302, with N=6 in the illustrated example. According to the illustrated example, the optimization module208has determined that the minimum or reduced M number of tiles that meets the target SNR is four (M=4), with the ESA300having four activated tiles302A and two in-active tiles302B.

In some embodiments, the optimization module208generates an exhaustive list of all possible M-from-N tile patterns. The number of possible tile patterns or permutations may be defined as

Accordingly, in the illustrated example in which N=6 and M=4, then the number of possible tile patterns is fifteen (S=15).FIG.3Billustrates each of the fifteen possible tile patterns304, with each possible tile pattern304specifying a unique permutation or arrangement of activated tiles302A.

In some embodiments, the optimization module208analyzes each possible tile pattern304to determine whether a possible tile pattern304complies with one or more requirements and constraints. In particular, in some embodiments, the requirements and constraints include a symmetry requirement, in which an arrangement of activated tiles302A in a possible tile pattern304must be symmetrical. Because of this symmetry requirement, resulting beam geometry may be compliant and reliable. The symmetry requirement may be associated with polarization and power constraints associated with the ESA, due to asymmetrical tile patterns requiring more power to emit a signal without significant noise, in some examples.FIG.3Billustrates an example of an asymmetrical tile pattern304A and a symmetrical tile pattern304B. In some embodiments, the optimization module208classifies certain ones of the possible tile patterns304(e.g., the symmetrical tile patterns304B) as feasible and eliminates the remaining ones of the possible tile patterns304(e.g., the asymmetrical tile patterns304A). In the illustrated example ofFIG.3B, the optimization module208eliminates ten of the possible tile patterns304due to non-compliance thereof with the symmetrical requirement.

As shown inFIG.3C, the optimization module208then constructs a graph310, in some embodiments. The graph310includes nodes312and edges314. The nodes312of the graph310correspond to the possible tile patterns304classified as feasible (e.g., symmetrical tile patterns304B). The edges314of the graph310define a number of shared or common tiles between respective tile patterns. For example, between the nodes312labelled “1” and “4,” the respective tile patterns share two common tiles, and the particular edge between Node 1 and Node 4 accordingly indicates the value 2. Likewise, the particular edge between Node 9 and Node 8 indicates that the respective tile patterns of Node 9 and Node 8 share three common tiles. Accordingly, if two tile patterns are non-overlapping, an edge between the corresponding two nodes would define a value of zero. The edges314of the graph310are directionless.

In some embodiments, the optimization module208then calculates the shortest path that traverses the graph. Specifically, the optimization module208searches for a path that visits each node exactly once and returns to the original node, with the path having a minimized “distance” or total edge value. It may be appreciated that this path resembles a solution to the Traveling Salesman problem. Thus, for example, one solution is to exhaustively compare lengths for all possible paths. For a graph310with X number of nodes312, there exist at most (X−1)! possible paths. Other path optimization solutions may be implemented.

The shortest path solution then may describe a cyclic power sequence among the feasible tile patterns by which the ESA can be operated. InFIG.3C, the shortest path316visits in order Node 1, Node 4, Node 9, Node 7, Node 8, and back to Node 1, and each of these nodes corresponds to a tile pattern. Due to the shortest path316being minimized with respect to edge values, the number of shared tiles between consecutive tile patterns in the sequence is minimized. Accordingly, when switching from a given tile pattern to the subsequent tile pattern, a maximum number of tiles are inactivated to allow for said tiles to cool and rest. Any given tile of the ESA has its cooling or resting time maximized by way of the shortest path316. In some embodiments, the ESA is operated according to the cyclic power sequence in a cyclic or repeated manner while in the reduced service mode and/or until a stop command is received. In some embodiments, after exiting the reduced service mode and/or receiving a stop command, the ESA is operated under normal conditions, for example, with all of the tiles being activated or powered.

Therefore, in some embodiments, the optimization module208determines a dynamic power sequence for an ESA according to graph minimum path. In some embodiments, this dynamic power sequence is pre-determined by the optimization module208and stored in association with the M and N parameters. In some embodiments, the optimization module208pre-determines an optimized sequence of tile patterns for each value of M for a given N total number of tiles in a given ESA. In some embodiments, the optimization module208is provided with optimized sequences corresponding to one or more values of M by a ground server, another vehicle, and/or the like.

In some embodiments, the ESA is powered according to a given tile pattern in the optimized power sequence for a respective dwelling time. For example, when the ESA powers up, the ESA enters a first power mode (that is, apply power to a first tile pattern in the optimized power sequence). The ESA dwells in the first power mode for a first time period T1, and then the ESA switches to a second power mode (that is, stop power to the first tile pattern, apply power to a second tile pattern in the optimized power sequence). The ESA dwell in the second power mode for a second time period T2, and continues through the optimized power sequence.

In some embodiments, the respective dwelling times (e.g., first time period T1, second time period T2) are determined based on information associated with a communication channel (e.g., a radio frequency channel) within which the ESA transmits or receives signals. For example, for time-slotted waveforms (e.g., TDMA, Mx-DMA), the dwelling time may be set equal to the integer number of time slots, as indicated by time division information associated with the communication channel, or channel characteristic information generally. For example, when deployed with Mx-DMA, T1=T2= . . . =n seconds. In some embodiments, the respective dwelling times are determined based on the shutdown temperature of the ESA. For example, for continuous time waveforms (e.g., CDMA, DVB-SX), the dwelling time in a particular tile pattern may be calculated as a function of estimated time for the tile set to reach shutdown temperature. Tile temperatures are sampled periodically, for example, via the temperature sensors of the antenna system, and the tile pattern's temperature is the highest temperature among all its tiles. Accordingly, in some embodiments, the antenna system may include a temperature sensor for each tile. For example, at the start of a first power mode, the temperature of a first tile pattern is 50° C., and the shutdown temperature of the antenna system is 75° C. The ESA may dwell in the first tile pattern until the temperature of the first tile pattern is 55° C., based on the total number of patterns in the power sequence, an offset from the shutdown temperature, the ambient temperature, the predicted temperature gradient, and/or the like. In some embodiments, the dwelling times for power sequences for the TX aperture and for the RX aperture may be independent.

Turning now toFIG.4, an example method400for determining an optimization for ESA operation is illustrated. For example, the method400may be performed by an antenna controller that operates an ESA. In some embodiments, the method400may be performed in advanced of the ESA requiring thermal load balancing, such that the optimization for ESA operation is pre-determined. In some embodiments, the method400is performed on demand to determine the optimization for ESA operation based on current states and usages of the ESA.

At402, the antenna controller identifies a subset of feasible, permissible, or compliant tile patterns out of a plurality of possible tile patterns, with each possible tile pattern having a reduced number of antenna tiles within an antenna configuration. For example, the antenna controller identifies the feasible, permissible, or compliant tile patterns based on a spatial symmetry (or lack thereof) across the specific tiles of each pattern. In some embodiments, alternative or in addition to spatial symmetry requirements, the subset of patterns is identified based on a number of shared tiles. For example, a maximum shared tile count is defined, and any tile pattern of the possible tile pattern that has at least the maximum shared tile count with any other tile pattern is eliminated from the subset.FIG.3Bdemonstrates the identification of a subset of tile patterns out of a plurality of possible tile patterns. In some embodiments, the identification of a subset of tile patterns promotes efficiency and feasibility of subsequent graph construction and path optimization operations.

At404, the antenna controller constructs a graph with nodes corresponding to the permissible patterns and edges corresponding to a shared tile count between respective permissible patterns. In order to do so, in some embodiments, each feasible or permissible tile pattern is associated with a unique identifier, which the antenna controller correlates or associates with a node of the graph.FIG.3Cillustrates an example of a graph constructed by the antenna controller at404.

At406, the antenna calculates an optimized path that traverses the graph with minimized distance. Because edge distances or lengths are defined according to shared tile count, minimization of path length corresponds to a minimization of shared tiles between consecutive tile patterns in the path. The optimized path may visit each node of the graph exactly once before returning to an original node. By including every node of the graph (or, every permissible tile pattern), there are more unique patterns to hop between, which maximizes inactivity time for a given tile. In some embodiments, a Traveling Salesman solution is used to calculate the optimized path.FIG.3Cindicates an example optimized path that traverses a graph with minimized distance.

At408, the antenna controller stores the optimized path in a database (e.g., database108inFIG.1A) in association with the reduced number of tiles and/or a particular antenna configuration. For example, the antenna controller pre-calculates or pre-determines the optimized path and stores the optimized path for later use in ESA operation when triggered. In some embodiments, the database stores a plurality of optimized paths. Because the optimized path is unique to the graph which is constructed primarily based on a reduced number of antenna tiles and an antenna configuration (e.g., a total number of antenna tiles and geometric layout or spatial arrangement thereof), the database may store the optimized path in reference to the reduced number of antenna tiles and the antenna configuration. Therefore, given a reduced number of antenna tiles and an antenna configuration, a specific optimized path may be retrieved from the database. In some embodiments, the antenna controller further determines dwelling times for patterns in the optimized path and stores the dwelling times with the optimized path in the database.

FIG.5illustrates an example method500for thermal load balancing an ESA. The example method500may be implemented by an antenna system to maximize an expected time before the antenna system reaches a shutdown temperature. In particular, the antenna system includes an ESA that includes antenna tiles operable in coordination with one another to emit and/or receive directed communication signals, and the antenna system further includes an antenna controller device that performs the method500to maximize an expected time before the ESA reaches a shutdown temperature. In some embodiments, the ESA is located on an aircraft, and the method500may be performed to improve communication capability between the aircraft and target systems, including ground stations and satellites.

At502, the antenna controller device determines a reduced number of antenna elements that minimally satisfies a signal quality requirement with respect to a target system. For example, the target system is a LEO satellite, and the reduced number of antenna elements is determined based on a position of the LEO satellite relative to the ESA and a target SNR for communicating with the LEO satellite.

At504, the antenna controller device selects a sequence of tile patterns each being a unique permutation of the reduced number of antenna tiles within the ESA. The sequence of tile patterns maximizes a non-operational time for each antenna tile. According to some embodiments, the antenna controller device selects the sequence of tile patterns based on performing method400ofFIG.4. In some embodiments, the antenna controller device selects the sequence of tile patterns from a plurality of sequences stored in a database. In connection with the selection of a sequence of tile patterns, the antenna controller device may determine a dwelling time for each tile pattern in the sequence. In some embodiments, the sequence of tile patterns is a plurality of tile patterns; that is, the antenna controller device selects a plurality of tile patterns. In some embodiments, the plurality of tile patterns does not imply a specific order or priority among the tile patterns.

At506, the antenna controller device operates the ESA according to the sequence of tile patterns to transmit/receive at least one communication signal via the ESA. In particular, the antenna controller device powers specific tiles of the ESA according to a first tile pattern of the sequence for a first time period, followed by powering specific tiles of the ESA according to a subsequent tile pattern of the sequence for a second time period, and so on.

The various embodiments introduced herein can be implemented by, for example, programmable circuitry (e.g., one or more microprocessors, programmed with software and/or firmware), or entirely in special-purpose hardwired circuitry (e.g., non-programmable circuitry), or in a combination of such forms. Special-purpose hardwired circuitry may be in the form of, for example, one or more application-specific integrated circuits (ASICs), programmable logic devices (PLDs), field-programmable gate array (FPGAs), etc. In some embodiments, the methods may be stored in the form of computer-executable instructions that are stored on a computer-readable medium. Alternatively, or in addition, cloud-based computing resources may be used for implementing the embodiments.

The embodiments set forth herein represent the necessary information to enable those skilled in the art to practice the embodiments and illustrate the best mode of practicing the embodiments. Upon reading the description in light of the accompanying figures, those skilled in the art will understand the concepts of the disclosure and will recognize applications of these concepts that are not particularly addressed herein. These concepts and applications fall within the scope of the disclosure and the accompanying claims.

The above description and drawings are illustrative and are not to be construed as limiting. Numerous specific details are described to provide a thorough understanding of the disclosure. However, in certain instances, well-known details are not described in order to avoid obscuring the description. Further, various modifications may be made without deviating from the scope of the embodiments.

As used herein, unless specifically stated otherwise, terms such as “processing,” “computing,” “calculating,” “determining,” “displaying,” “generating,” or the like, refer to actions and processes of a computer or similar electronic computing device that manipulates and transforms data represented as physical (electronic) quantities within the computer's memory or registers into other data similarly represented as physical quantities within the computer's memory, registers, or other such storage medium, transmission, or display devices.