Clear-channel system and related applications

Abstract

A wireless spread-spectrum communication system for transmitting data includes a plurality of end point transmitters and at least one receiver. The end point transmitters transmit data via a frequency-hopped spread-spectrum signal where the transmitting signal is sent without the benefit of frequency stabilization. The receiver is responsive to the frequency-hopping spread-spectrum signals and includes a correlator and a signal processor. The correlator samples at least a first portion of a preamble of the signal and correlates the portion of the preamble with a known preamble pattern to determine a probability of correlation. The signal processor applies a Fast Fourier Transform algorithm to the signal in response to the probability of correlation to track a narrowband frequency of the signal based on at least a second portion of the preamble and to decode data encoded within the signal subsequent to the preamble.

1 - 11 . (canceled) 
     
     
         12 . A method of identifying optimized bands in a frequency-hopping spread-spectrum (FHSS) system for a given location, the method comprising the steps of:
 providing a radio including a receiver, a transmitter, and a microprocessor;   using the radio to measure power levels in frequency bins in the industrial, scientific, and medical (ISM) band for a given location;   taking a plurality of measurements of the power levels over time;   using the microprocessor to derive a band profile of peak and average power levels across the entire ISM band from the measurements;   transmitting the band profile to a remote FHSS device having a data-storage device; and   transmitting FHSS signals to the radio over optimized channels identified by the band profile.   
     
     
         13 . The method of  claim 12 , wherein the band profile is transmitted to the remote FHSS device in the form of a lookup table. 
     
     
         14 . The method of  claim 12 , wherein the band profile is a first band profile, and the plurality of measurements are first measurements, and the method further comprising the steps of:
 repeating the step of using the radio to measure power levels in the frequency bins;   taking a plurality of second measurements over time;   using the microprocessor to derive a second band profile from the second measurements; and   transmitting the second band profile to the remote FHSS device.   
     
     
         15 . A method for transmitting data, comprising:
 providing a frequency-hopping spread-spectrum (FHSS) transmitter configured to transmit signals on predetermined channels within a predetermined frequency band;   providing a receiver configured to receive signals occurring throughout the predetermined frequency band;   taking a series of measurements of power level of the signals received on the predetermined channels within the predetermined frequency band;   evaluating the series of measurements over a predetermined time period;   constructing a time of day dependent band profile of the signal levels received on the predetermined channels;   identifying noisy channels within the predetermined channels based on the band profile; and   enabling the FHSS transmitter to adjust its transmission of signals to transmit signals avoiding the identified noisy channels.   
     
     
         16 . A method as in  claim 15 , further comprising:
 identifying relatively clear channels within the predetermined channels based on the band profile; and   enabling the FHSS transmitter to adjusts its transmission of signals to transmit signals on the relatively clear channels.   
     
     
         17 . A method as in  claim 15 , wherein enabling comprises storing the band profile in a table accessible by the FHSS transmitter. 
     
     
         18 . A method as in  claim 15 , further comprising:
 taking a second series of measurements of the power level of signals received on the predetermined channels within the predetermined frequency band;   evaluating the second series of measurements over a predetermined time period; and   updating the band profile based on the signal levels received on the predetermined channels during the second series of measurements.   
     
     
         19 . A method as in  claim 15 , further comprising:
 evaluating the series of measurements over a plurality of different time periods within a day; and   constructing a time-dependent band profile.   
     
     
         20 . A method as in  claim 19 , further comprising:
 evaluating the series of measurements to identify band information applicable throughout a day; and   constructing a band profile including time-dependent and daily information.