Information transfer using discrete-frequency signals and instantaneous frequency measurement

Abstract

A method of receiving information is provided. The method is performed at a system for information transfer. The method includes receiving a first signal pulse and determining a first frequency band associated with the first signal pulse. The method includes, in accordance with a determination that the first frequency band is a respective frequency band in a predefined set of frequency bands, determining, from a predefined set of symbols, a first symbol associated with the first frequency band and represented by the first signal pulse. Each frequency band in the predefined set of frequency bands is associated with a distinct respective symbol in the predefined set of symbols, and frequency bands in the predefined set of frequency bands, in aggregate, are not contiguous.

What is claimed is: 
     
         1 . A method of receiving information, comprising:
 receiving a first signal pulse;   determining a first frequency band associated with the first signal pulse; and   in accordance with a determination that the first frequency band is a respective frequency band in a first predefined set of frequency bands:
 determining, from a predefined set of symbols, a first symbol associated with the first frequency band and represented by the first signal pulse; 
   wherein:
 each frequency band in the first predefined set of frequency bands is associated with a distinct respective symbol in the predefined set of symbols; and 
 frequency bands in the first predefined set of frequency bands, in aggregate, are not contiguous. 
   
     
     
         2 . The method of  claim 1 , including:
 in accordance with the determination that the first frequency band is a respective frequency band in a first predefined set of frequency bands, providing the first symbol.   
     
     
         3 . The method of  claim 1 , further comprising:
 receiving a second signal pulse transmitted at least a predefined amount of time after the first signal pulse;   determining a second frequency band associated with the second signal pulse; and   in accordance with a determination that the second frequency band is a respective frequency band in the first predefined set of frequency bands:
 determining, from the predefined set of symbols, a second symbol associated with the second frequency band and represented by the second signal pulse. 
   
     
     
         4 . The method of  claim 1 , wherein:
 the first predefined set of frequency bands is associated with the predefined set of symbols using a lookup table; and   determining the first symbol associated with the first frequency band includes selecting the respective symbol associated with the first frequency band in the lookup table.   
     
     
         5 . The method of  claim 1 , wherein a duration of the first signal pulse is less than a predetermined duration. 
     
     
         6 . The method of  claim 1 , wherein a length of the first signal pulse is less than one full wavelength, and determining the first frequency band associated with the first signal pulse includes:
 determining a phase of the first signal pulse at a respective time;   determining a first frequency of the first signal pulse based on the determined phase of the first signal pulse at the respective time and on a rate of change with respect to time of the first signal pulse at the respective time; and   determining that the first frequency of the first signal pulse is in the first frequency band.   
     
     
         7 . The method of  claim 1 , wherein the predefined set of symbols includes two or more symbols associated with the first frequency band, each symbol of the two or more symbols associated with a respective pulse duration, and the method includes:
 determining a first pulse duration of the first signal pulse;   wherein determining the first symbol includes selecting the first symbol from the two or more symbols associated with the first frequency band based on the first pulse duration.   
     
     
         8 . The method of  claim 1 , wherein:
 the first signal pulse is received at a plurality of input channels of a receiver, each input channel associated with a respective frequency band in the first predefined set of frequency bands; and   determining the first frequency band associated with the first signal pulse includes:
 measuring channel power of each respective input channel; and 
 identifying a respective input channel having a highest measured channel power. 
   
     
     
         9 . The method of  claim 1 , wherein determining the first frequency band associated with the first signal pulse comprises:
 receiving the first signal pulse at a first frequency detection stage;   determining, using the first frequency detection stage, a first frequency range that includes the first frequency of the first signal pulse;   after determining the first frequency range, receiving the first signal pulse at a second frequency detection stage; and   determining, within the first frequency range, using the second frequency detection stage, a second frequency range that includes the first frequency of the first signal pulse, wherein the second frequency range is smaller than the first frequency range;   wherein the first frequency band corresponds to the second frequency range.   
     
     
         10 . The method of  claim 1 , further comprising, before receiving the first signal pulse:
 obtaining a third signal pulse;   determining a third frequency of the third signal pulse; and   comparing the third frequency to a predefined calibration frequency to determine a difference between the third frequency and the predefined calibration frequency;   wherein determining the first frequency band of the first signal pulse includes:
 determining an initial frequency of the first signal pulse; 
 determining an adjusted frequency of the first signal pulse based on applying the determined difference to the initial frequency; and 
 determining the first frequency band based on the adjusted frequency. 
   
     
     
         11 . The method of  claim 1 , wherein:
 the first predefined set of frequency bands includes a first respective frequency band and a second respective frequency band that is a nearest frequency band in the first predefined set of frequency bands to the first respective frequency band;   the first respective frequency band has a first center frequency;   the second respective frequency band has a second center frequency; and   a difference between the first center frequency and the second center frequency exceeds a predefined frequency difference threshold.   
     
     
         12 . The method of  claim 1 , including, after receiving the first signal pulse:
 receiving a control signal associating a second predefined set of frequency bands with the predefined set of symbols, wherein:
 the second predefined set of frequency bands is distinct from the first predefined set of frequency bands; 
 each frequency band in the second predefined set of frequency bands is associated with a distinct respective symbol in the predefined set of symbols; and 
 frequency bands in the second predefined set of frequency bands, in aggregate, are not contiguous; 
   after receiving the control signal, receiving a fourth signal pulse;   determining a third frequency band associated with the fourth signal pulse; and   in accordance with a determination that the third frequency band is a respective frequency band in the second predefined set of frequency bands:
 determining, from the predefined set of symbols, a third symbol associated with the third frequency band and represented by the fourth signal pulse. 
   
     
     
         13 . A system for information transfer, comprising:
 a receiver, configured to receive a first signal pulse; and   processing circuitry, configured to:
 receive a first signal pulse; 
 determine a first frequency band associated with the first signal pulse; and 
 in accordance with a determination that the first frequency band is a respective frequency band in a first predefined set of frequency bands:
 determine, from a predefined set of symbols, a first symbol associated with the first frequency band and represented by the first signal pulse; 
 
 wherein:
 each frequency band in the first predefined set of frequency bands is associated with a distinct respective symbol in the predefined set of symbols; and 
 frequency bands in the first predefined set of frequency bands, in aggregate, are not contiguous. 
 
   
     
     
         14 . A method of transmitting information, comprising:
 obtaining a first symbol, in a predefined set of symbols, for transmission;   determining a first frequency band, in a first predefined set of frequency bands, associated with the first symbol; and   transmitting a first signal pulse having a first frequency in the first frequency band;   wherein:
 each frequency band in the first predefined set of frequency bands is associated with a distinct respective symbol in the predefined set of symbols; and 
 frequency bands in the first predefined set of frequency bands, in aggregate, are not contiguous. 
   
     
     
         15 . The method of  claim 14 , further comprising:
 obtaining a second symbol, in the predefined set of symbols, for transmission;   determining a second frequency band, in the first predefined set of frequency bands, associated with the second symbol; and   after at least a predefined amount of time since transmitting the first signal pulse, transmitting a second signal pulse having a second frequency in the second frequency band.   
     
     
         16 . The method of  claim 14 , including, after transmitting the first signal pulse:
 transmitting a control signal associating a second predefined set of frequency bands with the predefined set of symbols; wherein:
 the second predefined set of frequency bands is distinct from the first predefined set of frequency bands; 
 each frequency band in the second predefined set of frequency bands is associated with a distinct respective symbol in the predefined set of symbols; and 
 frequency bands in the second predefined set of frequency bands, in aggregate, are not contiguous; 
   after transmitting the control signal, obtaining a third symbol, in the predefined set of symbols, for transmission;   determining a third frequency band, in the second predefined set of frequency bands, associated with the third symbol; and   transmitting a third signal pulse having a third frequency in the third frequency band.   
     
     
         17 . The method of  claim 16 , including:
 prior to transmitting the control signal associating the second predefined set of frequency bands with the predefined set of symbols:
 determining that a spectral density of a respective frequency band in the first predefined set of frequency bands satisfies a predefined threshold value; 
 identifying, from the predefined set of symbols, a respective symbol that is associated with the respective frequency band in the first predefined set of frequency bands; and 
 determining that a spectral density of a fourth frequency band, outside of the first predefined set of frequency bands, is below the predefined threshold value; 
   wherein:
 the second predefined set of frequency bands includes the fourth frequency band, and the respective symbol in the predefined set of symbols is associated with the fourth frequency band in the second predefined set of frequency bands. 
   
     
     
         18 . The method of  claim 14 , wherein the predefined set of symbols includes two or more symbols associated with the first frequency band, each symbol of the two or more symbols associated with a respective pulse duration, and the method includes:
 determining a first pulse duration based on the first symbol of the two or more symbols;   wherein a pulse duration of the first signal pulse corresponds to the first pulse duration.   
     
     
         19 . The method of  claim 14 , further comprising, before transmitting the first signal pulse, transmitting a plurality of successive pulses having one or more calibration frequencies. 
     
     
         20 . A system for information transfer, comprising:
 processing circuitry, configured to:
 obtain a first symbol, in a predefined set of symbols, for transmission; and 
 determine a first frequency band, in a first predefined set of frequency bands, associated with the first symbol; and 
   a transmitter, configured to transmit a first signal pulse having a first frequency in the first frequency band;   wherein:
 each frequency band in the first predefined set of frequency bands is associated with a distinct respective symbol in the predefined set of symbols; and 
 frequency bands in the first predefined set of frequency bands, in aggregate, are not contiguous.