Patent Publication Number: US-2023141890-A1

Title: Systems and methods for supporting near-real time propagation prediction and frequency management

Description:
BACKGROUND 
     Statement of the Technical Field 
     The present document concerns communication systems. More specifically, the present document concerns systems and methods for supporting near-real time propagation prediction and frequency management. 
     Description of the Related Art 
     Communication devices are well known. One such communication device is a High Frequency (HF) radio. The HF band (e.g., 3-30 MHz) has been used to provide connectivity between communication devices without the use of relays or other intermediate equipment. In the HF radio, propagation between radios are dependent on the following factors: time of day, time of year, year of the 11-year solar cycle, local noise and interference, Earth&#39;s geomagnetic activity, and/or solar weather. Carrier frequency selection needs to take these factors into consideration. Successful operations of the HF radio presently requires one or more of the following: an expert user that has in depth knowledge of the listed factors and which carrier frequency to use at any given time based on the listed factors; an assistant in the form of an Automatic Link Establishment (ALE) that has recent link information and facilitated communication link establishment between HF radios; and/or pre-mission planning using a propagation prediction program (e.g., Voice of America Coverage Analysis Program (VOACAP)). VOACAP generally involves periodically (e.g., hourly) generating Signal-to-Noise Ratio (SNR) predictions at a radio receiver based on long term monthly median data. These SNR predictions do not attempt to model day-to-day effects and are often made outside of the HF radios as part of overall system frequency planning. One can alternatively or additionally analyze measured SNR data from a variety of possible sources, with day-to-variances that can provide additional propagation insights. 
     SUMMARY 
     This document concerns systems and methods for operating a system. The methods comprise, by a processor: using a machine learning model to identify which frequency of a plurality of possible frequencies (that can be used by a communication device for wireless communications) is an inferred best frequency based on at least on one of weather report information and predicted weather information (e.g., predicted space weather information); performing operations to select a best frequency from the plurality of possible frequencies using the inferred best frequency and a frequency value selected by a link establishment process (e.g., an ALE process) of the communication device; and causing the communication device to communicate signals with the best frequency which was selected. 
     In some scenarios, the best frequency is selected based further on subjective information gathered from a user of the communication device or other individuals, sensor data (e.g., measured propagation parameters) and/or estimated propagation parameters. 
     In those or other scenarios, the best frequency is selected based on a weighted combination of the inferred best frequency and the frequency value. A weight may be selected for each of the inferred best frequency and the frequency value based on a confidence score associated therewith. The weight may have different values at different times. For example, a Look Up Table (LUT) can be accessed to retrieve weights associated with the confidence scores. Alternatively, the weights are set equal to the confidence scores. The present solution is not limited to the particulars of this example. The best frequency may be fed back and used to update the machine learning model. The processor can be internal to or external to the communication device. 
     The implementing systems can comprise: a processor; and a non-transitory computer-readable storage medium comprising programming instructions that are configured to cause the processor to implement a method for operating a system. The above described methods can also be implemented by a computer program product comprising a memory and programming instructions that are configured to cause a processor to perform operations. 
     The present document also concerns a communication device. The communication device comprises: a processor; and a non-transitory computer-readable storage medium comprising programming instructions that are configured to cause the processor to implement a method for controlling operations of the communication device. The programming instructions comprise instructions to: obtain an inferred best frequency generated by a machine learning model based on at least on one of weather report information and predicted weather information (e.g., predicted space weather information); select a best frequency from a plurality of frequencies using the inferred best frequency and a frequency value selected by a link establishment process (e.g., an ALE process) of the communication device; and tune the communication device to the best frequency. 
     In some scenarios, the best frequency is selected based further on subjective information gathered from a user of the communication device or other individuals, sensor data (e.g., measured propagation parameters) and/or estimated propagation parameters. 
     In those or other scenarios, the best frequency is selected based on a weighted combination of the inferred best frequency and the frequency value. The programming instructions may further comprise instructions to select a weight for each of the inferred best frequency and the frequency value based on a confidence score associated therewith. The weight may have different values at different times. The best frequency may be used to update the machine learning model. 
     The present document further concerns a non-transitory computer-readable medium having instructions stored thereon that, when executed by at least one computing device, cause the at least one computing device to perform operations comprising: use a machine learning model to identify which frequency of a plurality of possible frequencies that can be used by a communication device for wireless communications is an inferred best frequency based on at least on one of weather report information and predicted weather information; perform operations to select a best frequency from the plurality of possible frequencies using the inferred best frequency and a frequency value selected by a link establishment process of the communication device; and cause a communication device to be tuned to the best frequency. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       This disclosure is facilitated by reference to the following drawing figures, in which like numerals represent like items throughout the figures. 
         FIG.  1    provides an illustration of a system. 
         FIG.  2    provides an illustration of a communication device. 
         FIG.  3    provide an illustration of a computing device. 
         FIG.  4    provides an illustration that is useful for understanding how a machine learning model is trained in accordance with the present solution. 
         FIG.  5    provides an illustration that is useful for understanding how a trained machine learning model operates. 
         FIG.  6    provides an illustration that is useful for understanding how a best frequency is identified and/or selected using an inferred best frequency output from a trained machine learning model and other information. 
         FIG.  7    provides a graph that plots Signal-to-Noise Ratio (SNR) values for a plurality of different frequencies over time. 
         FIG.  8    provides a flow diagram of an illustrative method for operating a system such as that shown in  FIG.  1   . 
     
    
    
     DETAILED DESCRIPTION 
     It will be readily understood that the solution described herein and illustrated in the appended figures could involve a wide variety of different configurations. Thus, the following more detailed description, as represented in the figures, is not intended to limit the scope of the present disclosure but is merely representative of certain implementations in different scenarios. While the various aspects are presented in the drawings, the drawings are not necessarily drawn to scale unless specifically indicated. 
     Reference throughout this specification to features, advantages, or similar language does not imply that all the features and advantages that may be realized should be or are in any single embodiment of the invention. Rather, language referring to the features and advantages is understood to mean that a specific feature, advantage, or characteristic described in connection with an embodiment is included in at least one embodiment of the present invention. Thus, discussions of the features and advantages, and similar language, throughout the specification may, but do not necessarily, refer to the same embodiment. 
     Reference throughout this specification to “one embodiment”, “an embodiment”, or similar language means that a particular feature, structure, or characteristic described in connection with the indicated embodiment is included in at least one embodiment of the present solution. Thus, the phrases “in one embodiment”, “in an embodiment”, and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment. 
     As used in this document, the singular form “a”, “an”, and “the” include plural references unless the context clearly dictates otherwise. Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art. As used in this document, the term “comprising” means “including, but not limited to”. 
     Communication systems employing HF radios (such as those described above in the Background section of this paper) suffer from drawbacks. For example, there are relatively few expert users of HF radios at the present time (e.g., amateur radio operators, trained military users). Thus, the HF radios need to be re-designed for use by less skilled individuals. There are times when (i) ALE is either not available or the data has become stale over time and/or (ii) the user is in a stealth mode and does not want to transmit ALE over multiple frequencies. As data rates increase, latency and overhead become issues in HF radio applications. The HF radio needs to be configured to make recommendations for the best frequency for use at any given time in a near real-time manner with minimal impact on throughput and/or in a relatively low Size, Weight, Power and Cost (SWAP-C) manner. 
     The present solution provides systems and methods for supporting near-real time propagation prediction and frequency management. An Internet based resource can be provided to facilitate future mission planning, radio deployments and/or usage. Machine learning model(s) can be used to facilitate the present solution by providing a relatively fast SWAP-centric propagation aid to communication devices (e.g., HF radios). The machine learning model(s) can include, but is(are) not limited to, deep learning models such as Convolutional Neural Network (CNN) models. 
     The machine learning model(s) can be trained to infer a best frequency based on various information (e.g., weather report information, predicted weather information, user inputs, etc.). The training data can include, but is not limited to, standard propagation predictions from a propagation prediction program (e.g., VOACAP); outputs from machine learning algorithms using globally received propagation assessment signals (e.g., Weak Signal Propagation Reporter (WSPR)-like signals); observed data parameters for solar flux, planetary K, planetary A, space weather and/or geomagnetic alerts from a weather center (e.g., National Oceanic and Atmospheric Administration (NOAA) Space Weather Prediction Center (SWPC)); and/or other sources (e.g., solar flares, customer test data, internal test data, etc.). Parameters of the machine learning model(s) can be set on the communication devices prior to deployment and/or updated after deployment via over the air transmission(s). The output of the machine learning model(s) is referred to herein as inferred best frequency(ies). The output(s) is(are) then provided to another component of the system. 
     At this component, operations are performed to determine the best frequency to use at a past, present and/or future time based on a weighted combination of inputs. The inputs include, but are not limited to, the inferred best frequency(ies) output from the trained machine learning model(s), user inputs, subjective data (e.g., what frequency the user or other individual(s) believe is a good frequency to use at a given time), locally generated propagation measurement information (e.g., ALE measurements by an HF radio), remotely generated propagation measurement information (e.g., ALE measurements by a fielded system external to the HF radio), and/or estimated propagation parameters (e.g., daily estimations from voice propagation reports such as WWV radio station reports). 
     The present solution will be described below in relation to HF radios. The present solution is not limited in this regard and can be employed in other non-HF radio applications. 
     Referring now to  FIG.  1   , there is provided an illustration of an illustrative system  100  implementing the present solution. System  100  comprises weather center(s)  102 , data source(s)  132 , communication devices  104 ,  106 , . . . ,  108 , a network  110 , sever(s)  112  and datastore(s)  130 . The weather center(s)  102  include observation post(s) where weather conditions (e.g., Earth and space) and meteorological data are observed and recorded. The weather center(s)  102  can include, but are not limited to, a NOAA SWPC and/or other weather center(s). The recorded weather and/or meteorological data may be communicated from the weather center(s)  102  to the communication device(s)  104 - 108  and/or server(s)  112  via communication link(s)  114 - 122  and/or network  110 . 
     The data source(s)  132  can include any source of other information that is relevant for determining a best frequency to use for wireless communications at any given time. Such other information includes, but is not limited to, predicted weather information, time information, amateur radio user information, and/or subjective information (e.g., opinions of individual(s)). The information may be communicated from the data source(s)  132  to the communication device(s)  104 - 108  and/or server(s)  112  via communication link(s)  134 ,  116 - 122 ,  126  and/or network  110 . 
     Communication link(s)  114 ,  122 ,  134  is(are) shown as being wireless communication link(s). In some scenarios, communication link(s)  114 ,  122 ,  134  can alternatively or additionally comprise wired communication link(s). Network  110  can include, but is not limited to, the Internet, a radio communications network, and/or a telephony network (e.g., a cellular network). 
     The communication devices  104 - 108  are configured to communicate directly with each other via wireless communication links  116 ,  118 ,  124  and/or indirectly with each other via network  110  (e.g., using communication links  120 ,  126 ). These communications can include, but are not limited to, voice communications, data communications, media communications, talk group communications, and/or Push-to-Talk communications. The communication devices  104 - 108  can include, but are not limited to, HF radios configured to transmit and receive radio signals with frequencies between 3 MHz and 30 MHz. During operation, a transmitted radio signal propagates through the Earth&#39;s atmosphere, bounces or refracts off the ionosphere, and returns to Earth where it is received by receiving communication device(s) that are tuned to the same frequency as that of the transmitting communication device. The manner in which such tuning is achieved will become evident as the discussion progresses. 
     The communication devices  104 - 108  are also configured to communicate with remote server(s)  112 . The server(s)  112  is(are) provided to facilitate training of machine learning models and/or deployment of the trained machine learning model(s) to the communication devices  104 - 108 . New or updated machine learning models can be deployed daily or at other times. The machine learning model(s) may be trained to facilitate the provision of a relatively fast SWAP-centric propagation aid to the communication devices  104 - 108 . The machine learning model(s) can include, but are not limited to, deep learning models such as CNN models. 
     The machine learning model(s) can be trained to infer a best frequency based on various information (e.g., weather report information, predicted weather information, user input information, and/or other information). The training data includes, but is not limited to: standard propagation predictions from a propagation prediction program (e.g., VOACAP); outputs from machine learning algorithms using globally received propagation assessment signals (e.g., WSPR signals); observed data parameters for solar flux, planetary K, planetary A, space weather and/or geomagnetic alerts which were recorded by weather center(s)  102 ; and/or other information from server(s)  112  (e.g., solar flare event information, test data, etc.). Parameters of the machine learning model(s) can be set prior to deployment of the communication devices in the field and/or updated while the communication devices are in the field via over the air transmissions. The output of the machine learning algorithm(s) is(are) referred to herein as inferred best frequency(ies). 
     The inferred best frequency(ies) is(are) used by the communication device(s)  104 - 108  to determine the best frequency to use at a past, present and/or future time. Other information may also be used based on a weighted combination of inputs. The inputs include, but are not limited to, the inferred best frequency(ies) output from the trained machine learning model, user inputs, subjective data (e.g., what the user or other individual(s) believe is the good frequency to use at a given time), locally generated propagation measurement information (e.g., ALE measurements by an HF radio), remotely generated propagation measurement information (e.g., ALE measurements by a fielded system external to the HF radio), and/or estimated propagation parameters (e.g., daily estimations from voice propagation reports such as WWV radio station reports). Once a determination is made, the communication device(s) may automatically tune(s) to the best frequency. In some scenarios, the user(s) of the communication device(s) may be prompted to authorize such frequency tuning. 
     Referring now to  FIG.  2   , there is provided a more detailed block diagram of a communication device  200 . The communication devices  104 ,  106 ,  108  of  FIG.  1    can be the same as or similar to communication device  200 . As such, the following discussion of communication device  200  is sufficient for understanding communication devices  104 ,  106 ,  108  of  FIG.  1   . Some or all the components of the communication device  200  can be implemented as hardware, software and/or a combination of hardware and software. The hardware includes, but is not limited to, one or more electronic circuits. 
     Communication device  200  may include more or less components than those shown in  FIG.  2   . However, the components shown are sufficient to disclose an illustrative embodiment implementing the present solution. The hardware architecture of  FIG.  2    represents one embodiment of a representative device configured to facilitate near-real time propagation prediction and frequency management as described herein. As such, communication device  200  of  FIG.  2    implements methods for supporting near-real time propagation prediction and frequency management in accordance with embodiments of the present solution. Such methods are described below in detail. 
     As shown in  FIG.  2   , the communication device  200  comprises an antenna  202  for receiving and transmitting communication signals over a wireless communications link. A receive/transmit (Rx/Tx) switch  204  selectively couples the antenna  202  to the transmitter circuitry  206  and receiver circuitry  208  in a manner familiar to those skilled in the art. Although a single antenna  202  and transceiver  204 / 206 / 208  is shown in  FIG.  2   , the present solution is not limited in this regard. Communication device  200  can alternatively comprise a first antenna and a first transceiver for handling a first type of wireless communications (e.g., telephony or satellite communications), as well as a second antenna and a second transceiver for handling a second type of wireless communications (e.g., PTT communications). 
     The receiver circuitry  208  decodes the communication signals received from an external communication device to derive information therefrom. The receiver circuitry  208  is coupled to a controller  260  via an electrical connection  234 . The receiver circuitry  208  provides decoded communication signal information to the controller  260 . The controller  260  uses the decoded communication signal information in accordance with the function(s) of the communication device  200 . The controller  260  also provides information to the transmitter circuitry  206  for encoding information and/or modulating information into communication signals. Accordingly, the controller  260  is coupled to the transmitter circuitry  206  via an electrical connection  238 . The transmitter circuitry  206  communicates the communication signals to the antenna  202  for transmission to an external device. 
     An antenna  240  is coupled to Global Positioning System (GPS) receiver circuitry  214  for receiving GPS signals. The GPS receiver circuitry  214  demodulates and decodes the GPS signals to extract GPS location information therefrom. The GPS location information indicates the location of the communication device  200 . The GPS receiver circuitry  214  provides the decoded GPS location information to the controller  260 . As such, the GPS receiver circuitry  214  is coupled to the controller  260  via an electrical connection  236 . The present solution is not limited to GPS based methods for determining a location of the communication device  200 . Other methods for determining a location of a communication device can be used with the present solution without limitation. The controller  260  uses the decoded GPS location information in accordance with the function(s) of the communication device  200 . For example, the GPS location information and/or other location information can be used to generate a geographic map showing the location of the communication device  200  (e.g., relative to other communication devices, buildings and/or landmarks). 
     The controller  260  stores the decoded signal information and the decoded GPS location information in its internal memory  212 . Accordingly, the controller  260  comprises a Central Processing Unit (CPU)  210  that is connected to and able to access the memory  212  through an electrical connection  232 . The memory  212  can be a volatile memory and/or a non-volatile memory. For example, the memory  212  can include, but is not limited to, a Random Access Memory (RAM), a Dynamic Random Access Memory (DRAM), a Static Random Access Memory (SRAM), Read-Only Memory (ROM) and/or flash memory. The memory  212  can also have stored therein software applications  252  and/or instructions  250 . The software applications  252  include, but are not limited to, applications operative to: facilitate wireless communications with external devices; and/or facilitate the near-real time propagation prediction and frequency management in accordance with the present solution. An illustrative method for supporting near-real time propagation prediction and frequency management is described below in relation to  FIGS.  4 - 8   . 
     At least some of the hardware entities  232  perform actions involving access to and use of memory  212 . In this regard, hardware entities  232  may include microprocessors, Application Specific Integrated Circuits (ASICs) and other hardware. Hardware entities  232  may include a microprocessor programmed to: facilitate wireless communications with external devices; and/or facilitate the near-real time propagation prediction and frequency management in accordance with the present solution. In this regard, the microprocessor can access and run applications  252  installed on the communication device  200 . The applications  252  can use machine learning algorithm(s) and/or model(s)  254  for various purposes (e.g., to provide a relatively fast SWAP-centric propagation aid to the communication device). 
     The application(s)  252  may implement Artificial Intelligence (AI) that provides the communications device  200  with the ability to automatically learn and improve data analytics from experience without being explicitly programmed. The application(s)  252  employ(s) one or more machine learning algorithms  254  that learn various information from accessed data (e.g., via pattern recognition and prediction making). Machine learning algorithms are well known in the art. For example, in some scenarios, the machine learning application  254  employs a supervised learning algorithm, an unsupervised learning algorithm, and/or a semi-supervised algorithm. The machine learning algorithm(s) may be used to train the machine learning model(s) and/or to make frequency decisions based on data analysis (e.g., weather report information, predicted weather information, captured sensor information and other information). The data analysis can be achieved using the trained machine learning model(s). 
     The machine learning model(s) can be trained to infer a best frequency based on various information. The training data includes, but is not limited to: standard propagation predictions from a propagation prediction program (e.g., VOACAP); globally received propagation assessment signals (e.g., WSPR-like signals); observed data parameters for solar flux, planetary K, planetary A, space weather and/or geomagnetic alerts from a weather center (e.g., NOAA SWPC); and/or other sources (e.g., solar flares, customer test data, internal test data, etc.). Parameters of the machine learning model(s) can be set prior to deployment of the communication device  200  in the field and/or updated while in the field via Over-The-Air (OTA) transmission(s). Confidence score(s) is(are) output from the machine learning model along with the inferred best frequency(ies). These confidence score(s) can be used to select weights for the inferred best frequency(ies) as described below. 
     The output(s) of the machine learning algorithm(s) is(are) then provided to the CPU  210  for use in making a determination as to the best frequency to use at a past, present and/or future time. Other information can also be used to make this determination. This other information includes, but is not limited to, local and distributed ALE measurements by a fielded operating system, and/or daily estimated parameters from voice propagation reports. The inferred best frequency(ies) and other information may be weighted and combined to produce a score. The score may then be compared to threshold values associated with the possible frequencies that can be used by the communication device  200  for wireless communications. One of the frequencies is selected based on the results of the comparisons. The communication device may then be configured to perform wireless communication using the selected frequency. The tuning to the selected frequency can be automatic or in response to a user input. 
     In some scenarios, the weight for each input value is selected by the communication device  200  based on the associated confidence score and/or other criteria (e.g., type of information). For example, a first confidence score (e.g., 92%) is associated with an ALE measurement at time t 1 , and a second different confidence score (e.g., 76%) is associated with an ALE measurement at time t 2 . At time t 1 , the communication device selects a first weight w 1  to be used for generating the score. At time t 2 , the communication device selects a second different weight w 2  to be used for generating the score. The present solution is not limited to the particulars of this example. 
     In some scenarios, a different range of threshold values is defined for each possible frequency or set of possible frequencies. For example, a first frequency f1 (e.g., 14 MHz) is selected when the score s is greater than a first threshold thr1 and less than a second threshold thr2 (i.e., thr1&lt;s&lt;thr2). A second different frequency f2 (e.g., 10 MHz) is selected when the score s is greater than a third threshold thr3 and less than the first threshold thr1 (i.e., thr3&lt;s&lt;thr1). The present solution is not limited to the particulars of this scenario. Other techniques can be used to select the best frequency. 
     The hardware entities  232  can include a disk drive unit  234  comprising a computer-readable storage medium  236  on which is stored one or more sets of instructions  250  (e.g., software code) configured to implement one or more of the methodologies, procedures, or functions described herein. The instructions  250  can also reside, completely or at least partially, within the memory  212  and/or within the CPU  210  during execution thereof by the computing device  200 . The memory  212  and the CPU  210  also can constitute machine-readable media. The term “machine-readable media”, as used here, refers to a single medium or multiple media (e.g., a centralized or distributed database, and/or associated caches and servers) that store the one or more sets of instructions  250 . The term “machine-readable media”, as used here, also refers to any medium that is capable of storing, encoding or carrying a set of instructions  250  for execution by the computing device  200  and that cause the computing device  200  to perform any one or more of the methodologies of the present disclosure. 
     The user interface  230  comprises input devices  216  and output devices  224 . The input devices  216  include, but are not limited to, a keypad  220 , a microphone  222 , and buttons (not shown). The buttons can enable a user-software interaction to initiate a wireless communication, for example, using the frequency which was determined by the CPU  210  to be the best frequency for use at a given time. 
     The output devices  224  include, but are not limited to, a speaker  226  and a display  228 . During operation, one or more GUIs may be presented to the user of the communication device  200  via the display  228 . For example, a GUI may be displayed on display  228  for enabling a user-software interaction to initiate a wireless communication, for example, using the frequency which was determined by the CPU  210  to be the best frequency for use at a given time. 
     Referring now to  FIG.  3   , there is shown a hardware block diagram comprising an illustrative computing device  300 . Server  112  of  FIG.  1    can be the same as or substantially similar to computing device  300 . As such, the discussion of computing device  300  is sufficient for understanding server  112  of  FIG.  1   . 
     Computing device  300  may include more or less components than those shown in  FIG.  3   . However, the components shown are sufficient to disclose an illustrative solution implementing the present invention. The hardware architecture of  FIG.  3    represents one implementation of a representative computing device configured to enable support of near-real time propagation prediction and frequency management as described herein. As such, the computing device  300  of  FIG.  3    implements at least a portion of the method(s) described herein. 
     Some or all the components of the computing device  300  can be implemented as hardware, software and/or a combination of hardware and software. The hardware includes, but is not limited to, one or more electronic circuits. The electronic circuits can include, but are not limited to, passive components (e.g., resistors and capacitors) and/or active components (e.g., amplifiers and/or microprocessors). The passive and/or active components can be adapted to, arranged to and/or programmed to perform one or more of the methodologies, procedures, or functions described herein. 
     As shown in  FIG.  3   , the computing device  300  comprises a user interface  302 , a CPU  306 , a system bus  310 , a memory  322  connected to and accessible by other portions of computing device  300  through system bus  310 , and hardware entities  314  connected to system bus  310 . The user interface can include input devices (e.g., a keypad  350 ) and output devices (e.g., a speaker  352 , a display  354 , and/or light emitting diodes  356 ), which facilitate user-software interactions for controlling operations of the computing device  300 . 
     At least some of the hardware entities  314  perform actions involving access to and use of memory  322 , which can be a RAM, a disk driver and/or a CD-ROM. Hardware entities  314  can include a disk drive unit  316  comprising a computer-readable storage medium  318  on which is stored one or more sets of instructions  320  (e.g., software code) configured to implement one or more of the methodologies, procedures, or functions described herein. The instructions  320  can also reside, completely or at least partially, within the memory  322  and/or within the CPU  306  during execution thereof by the computing device  300 . The memory  322  and the CPU  306  also can constitute machine-readable media. The term “machine-readable media”, as used here, refers to a single medium or multiple media (e.g., a centralized or distributed database, and/or associated caches and servers) that store the one or more sets of instructions  320 . The term “machine-readable media”, as used here, also refers to any medium that is capable of storing, encoding or carrying a set of instructions  320  for execution by the computing device  300  and that cause the computing device  300  to perform any one or more of the methodologies of the present disclosure. 
     In some scenarios, the hardware entities  314  include an electronic circuit (e.g., a processor) programmed for facilitating near-real time propagation prediction and frequency management. In this regard, it should be understood that the electronic circuit can access and run application(s)  324  and/or a machine learning application(s)  326  installed on the computing device  300 . 
     The machine learning application(s)  326  may implement AI that provides the computing device  300  with the ability to automatically learn and improve data analytics from experience without being explicitly programmed. The machine learning application(s) employ(s) one or more machine learning algorithms that learn various information from accessed data (e.g., via pattern recognition and prediction making). Machine learning algorithms are well known in the art. For example, in some scenarios, the machine learning application  326  employs a supervised learning algorithm, an unsupervised learning algorithm, and/or a semi-supervised algorithm. The learning algorithm(s) is(are) used to model frequency decisions based on data analysis (e.g., captured sensor information and other information). 
     Referring now to  FIG.  4   , there is provided an illustration that is useful for understanding how a machine learning model is trained in accordance with the present solution. The machine learning model is trained by providing a machine learning algorithm  410  with training data to learn from. The machine learning algorithm  410  finds pattern(s) in the training data that map input data attributes to predicted best frequency(ies). The output of the machine learning algorithm  410  is a machine learning model  412  that is trained to infer best frequency(ies) based on the pattern(s). 
     The training data can include, but is not limited to, measured data  402 , observed data  404 , predicted data  406  and/or other data  408 . The measured data  402  can include, but is not limited to, contents of reception reports from probing potential propagation paths (e.g., on HF bands) with low-power transmissions (e.g., via WSPR beacon(s)  256  of  FIG.  2   ) and/or other sensor data (e.g., by sensor(s)  256  of  FIG.  2   ). The observed data  404  can include, but is not limited to, solar flux, planetary K information specifying fluctuations in the geomagnetic field at specific geographic location(s), a planetary A value representing an average amount of fluctuation in the geomagnetic field at specific geographic location(s) throughout a given day, space weather and/or contents of geomagnetic alerts from NOAA SWPC. The predicted data  406  can include, but is not limited to, propagation predictions made using a radio propagation model (e.g., a VOACAP model that used empirical data to predict point-to-point path loss and coverage of a transceiver given two antennas, solar weather and/or time/date). The other data  408  can include, but is not limited to, solar flare event data, solar flare predictions, and/or test data. 
     Referring now to  FIG.  5   , there is provided an illustration that is useful for understanding how inferred best frequency(ies) is(are) output using the trained machine learning model  412  of  FIG.  4   . The machine learning model is trained to recognize patterns in various types of information  502 - 508 . The machine learning model can include, but is not limited to, a CNN model. The information input into the machine learning model can include, but is not limited to, weather report information  502  (e.g., broadcast media report information issued on the Internet, daily estimations from voice propagation reports such as WWV radio station reports and/or NOAA radio station live reports), predicted weather information  504  (e.g., NOAA weather predictions), user input information  506  (e.g., actual weather conditions, opinions with regard to which frequency should be used, etc.) and/or other information  508  (e.g., preloaded default frequency values). Once a pattern is detected in the information  502 - 508 , the machine learning model selects the frequency which is associated with the pattern. The machine learning model may also obtain or compute a confidence score for the selected frequency. Techniques for computing confidence scores by machine learning models are well known. 
     Referring now to  FIG.  6   , there is provided an illustration that is useful for understanding how a best frequency is identified and/or selected in accordance with the present solution. The best frequency is identified/selected in block  608  using various information. This information includes, but is not limited to, the inferred best frequency(ies) output from the trained machine learning algorithm, a frequency value selected by a link establishment process (e.g., ALE value), estimated propagation parameter(s) (e.g., daily estimations from voice propagation reports such as WWV radio station reports), and/or other information (e.g., user inputs, subjective data reflecting the opinions of individual(s) relating to which frequency should be used at a given time, and/or sensor data (e.g., generated by sensors of the communication device or external device)). The sensor data can include, but is not limited to, measured propagation parameters and/or weather conditions (e.g., Earth and/or space). 
     In block  608 , weights are selected for each input  604 - 610  based on confidence scores associated therewith and/or other criteria (e.g., type of information). For example, a first weight w1 is selected for the inferred best frequency based on its associated confidence score, while a second weight w2 is selected for radio measurement information  604  (e.g., an ALE value) based on its associated confidence score, a third weight w3 is selected for an estimated propagation parameter (e.g., a WWV radio station report parameter value) based on its associated confidence score and/or the type of parameter (e.g., solar radiation storm level, planetary k index, geomagnetic storm level, etc.), and/or a fourth weight w4 is selected for the other information based on its confidence score and/or the type of information (e.g., user input or individual&#39;s opinion). Accordingly, the score can be defined in accordance with the following mathematical equation (1). 
         s =( w 1· I )+( w 2· M )+( w 3· E )+( w 4· O )  (1)
 
     where s represents the score, I represents an inferred best frequency output from a trained machine learning model, M represents a radio measurement, E represents an estimated propagation parameter, and O represents other information. The present solution is not limited to the manner in which the score is computed in this example. Other algorithms can be employed to compute the score. 
     Once the score s is computed, the score may be compared to one or more threshold values. For example, with reference to  FIG.  7   , a communication device is configured to communicate using frequencies 3.6 MHz, 7.0 MHz, 10.1 MHz, 14.1 MHz, 21.1 MHz and 28.0 MHz. A frequency of 3.6 MHz is selected as the best frequency when the score s is less than a first threshold thr1. A frequency of 7.0 MHz is selected as the best frequency when the score s is greater than the first threshold thr1 and less than a second threshold thr2. A frequency of 10.1 MHz is selected as the best frequency when the score s is greater than the second threshold thr2 and less than a third threshold thr3, and so on. A frequency of 28.0 MHz is selected as the best frequency when the score s is greater than an N th  threshold thrN. As shown in  FIG.  7   , the system selects 14.1 MHz for use at 23:00 UTC. The present solution is not limited to the particulars of this example. 
     Other algorithms can be used to select the best frequency  610 . For example, the best frequency is selected based on ALE information shown in the following Table 1 and machine learning information shown in the following Table 2. 
                             TABLE 1               Frequency (MHz)   Estimated SNR (dB)   Confidence Level (0 to 6)                                            3.6   −50   5       7.0   −15   5       10.1   −20   5       14.1   −9   5.5       21.1   −50   4       28   −50   3                    
The ALE process result suggests that 14.1 MHz should be used because it is associate with the highest estimated SNR.
 
                             TABLE 2               Frequency (MHz)   Estimated SNR (dB)   Confidence Level (0 to 3)                                            3.6   −45   3       7.0   −12   3       10.1   −14   3       14.1   −10   3       21.1   −49   2.9       28   −50   2.8                    
The machine learning model result suggests that 14.1 MHz should be used because it is associate with the highest estimated SNR. The best frequency is selected using the information in Table 1, Table 2 as shown by the following mathematical equations (2)-(4).
 
         SNR =( SNR   ALE  conf 1 )+( SNR   ML  conf 2 )  (2)
 
       conf 1 =conf ALE /(conf ALE +conf ML )  (3)
 
       conf 2 =conf ML /(conf ALE +conf ML )  (4)
 
     where SNR ALE  represents an SNR estimate generated by an ALE process, SNR ML  represents an SNR estimate generated by a machine learning model, conf ALE  represents a confidence level associated with SNR ALE , and conf ML  represents a confidence level associated with SNR ML . The results from computations using the above mathematical equations (2)-(4) are presented in the following Table 3. 
                                 TABLE 3                       Frequency (MHz)   Estimated SNR (dB)                                                    3.6   −48.125           7.0   −13.875           10.1   −17.75           14.1   −9.35           21.1   −49.58           28   −49.95                        
Since 14.1 MHz is associated with the highest SNR, the system selects this frequency as the best frequency. The present solution is not limited to the particulars of this technique for selecting the best frequency.
 
     In other scenarios, other information may be considered in additional to the ALE values of Table 1 and machine learning values of Table 2. The other information can include, but is not limited to, an opinion of an operator. Mathematical equations (2)-(4) can be modified as shown below to account for the other information. 
         SNR =( SNR   ALE  conf 1 )+( SNR   ML  conf 2 )+( SNR   other  conf 3 )  (5)
 
       conf 3 =conf other /(conf ALE +conf other )  (6)
 
     where SNR other  represents an SNR estimate input into the system by the operator, and conf other  represents a confidence level associated with SNR other . The present solution is not limited to the particulars of this example. 
     Referring now to  FIG.  8   , there is provided a flow diagram of an illustrative method  800  for operating a system (e.g., system  100  of  FIG.  1   ). Method  800  begins with  802  and continues with  804  where a machine learning model (e.g., machine learning mode  254  of  FIGS.  2  and/or  326    of  FIG.  3   ) is trained to infer a best frequency for a communication device (e.g., communication device  104 ,  106  or  108  of  FIGS.  1  and/or  200    of  FIG.  2   ). This training can be performed at a computing device (e.g., server(s)  112  of  FIG.  1    and/or computing device  300  of  FIG.  3   ) remote from the communication device. In some scenarios, the trained machine learning model is deployed to the communication device. 
     In  806 , the communication device obtains weather report information and/or predicted weather information. The weather report information can include, but is not limited to, WWV OTA reports. The predicted weather information can include, but is not limited to, NOAA predicted weather conditions for Earth and/or space. Other information may also be optionally obtained in  806 . This other information includes, but is not limited to, user input information (e.g., actual weather conditions, opinions as to which frequency should be used, etc.) and/or preloaded default frequency values. 
     In  808 , the machine learning model (e.g., machine learning mode  254  of  FIGS.  2  and/or  326    of  FIG.  3   ) is used to identify which frequency of a plurality of possible frequencies (e.g., frequencies 3.6 MHz, 7.0 MHz, 10.1 MHz, 14.1 MHz, 21.1 MHz and/or 28.0 MHz of  FIG.  7   ) that can be used by a communication device (e.g., communication device  104 ,  106  or  108  of  FIGS.  1  and/or  200    of  FIG.  2   ) for wireless communications is an inferred best frequency based on the information obtained in  806 . The operations of  808  can be performed by the communication device or a computing device external to the communication device (e.g., by a server of a cloud service provider). 
     In  810 , a best frequency is selected using the inferred best frequency output from the trained machine learning model, a frequency value selected by a link establishment process (e.g., an ALE process) of the communication device, and/or other information (e.g., subjective information gathered from a user of the communication device or other individuals, sensor data and/or estimated propagation parameters). 
     In those or other scenarios, the best frequency is selected based on a weighted combination of the inferred best frequency, the frequency value and/or other information. A weight may be selected for each of the inferred best frequency, the frequency value and/or other information based on a confidence score associated therewith. The weight may have different values at different times. 
     In  812 , the communication device is then caused to tune to the best frequency. The communication device may then optionally communicate signals with the best frequency, as shown by  814 . The best frequency and/or information used to select the same may be feedback and used to update the machine learning model as shown by  816 . Subsequently,  818  is performed where method  800  ends or other operations are performed (e.g., return to  806 ). 
     The implementing systems of method  800  can comprise: a processor; and a non-transitory computer-readable storage medium comprising programming instructions that are configured to cause the processor to implement a method for operating a system. The above described methods can also be implemented by a computer program product comprising a memory and programming instructions that are configured to cause a processor to perform operations. 
     The described features, advantages and characteristics disclosed herein may be combined in any suitable manner. One skilled in the relevant art will recognize, in light of the description herein, that the disclosed systems and/or methods can be practiced without one or more of the specific features. In other instances, additional features and advantages may be recognized in certain scenarios that may not be present in all instances. 
     Although the systems and methods have been illustrated and described with respect to one or more implementations, equivalent alterations and modifications will occur to others skilled in the art upon the reading and understanding of this specification and the annexed drawings. In addition, while a particular feature may have been disclosed with respect to only one of several implementations, such feature may be combined with one or more other features of the other implementations as may be desired and advantageous for any given or particular application. Thus, the breadth and scope of the disclosure herein should not be limited by any of the above descriptions. Rather, the scope of the invention should be defined in accordance with the following claims and their equivalents.