Spread spectrum communications system and method utilizing chaotic sequence
First Claim
1. A method for coherently modulating and demodulating a chaotic sequence spread spectrum signal within a communication system, comprising:
- channel encoding, by a transmitter of said communication system, a carrier with a plurality of information symbols;
generating an identical string of discrete time chaotic samples at said transmitter and a receiver of said communication system byselecting a plurality of polynomial equations;
using residue number system (RNS) arithmetic operations to respectively determine a plurality of solutions for said plurality of polynomial equations, said plurality of solutions iteratively computed and expressed as RNS residue values; and
determining a series of digits in a weighted number system based on said plurality RNS residue values;
modulating, at said transmitter, said carrier in a chaotic manner using said string of discrete time chaotic samples, each of said discrete time chaotic samples having a shorter sample time interval than a duration of said plurality of information symbols;
utilizing, at said transmitter, an accurate time reference to minimize a timing difference uncertainty between each said string of discrete time chaotic samples generated at said transmitter and said receiver;
synchronizing, at said receiver, each said string of discrete time chaotic samples in time and frequency; and
maintaining synchronization of said string of discrete time chaotic samples in time and frequency at each said transmitter and said receiver for a duration of an information transfer.
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Abstract
A method is provided for generating a coherent chaotic sequence spread spectrum communications system. The method includes phase modulating a carrier with information symbols. The method also includes generating a string of discrete time chaotic samples. The method further includes modulating the carrier in a chaotic manner using the string of discrete time chaotic samples. Each of the discrete time chaotic samples has a shorter sample time interval than the duration of the information symbols. The generating step includes selecting a plurality of polynomial equations. The generating step also includes using residue number system (RNS) arithmetic operations to respectively determine solutions for the polynomial equations. The solutions are iteratively computed and expressed as RNS residue values. The generating step further includes determining a series of digits in the weighted number system based on the RNS residue values. The method further includes synchronizing the chaos generated at the receiver with that generated at the transmitter without periodic transfer of state update information.
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Citations
30 Claims
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1. A method for coherently modulating and demodulating a chaotic sequence spread spectrum signal within a communication system, comprising:
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channel encoding, by a transmitter of said communication system, a carrier with a plurality of information symbols; generating an identical string of discrete time chaotic samples at said transmitter and a receiver of said communication system by selecting a plurality of polynomial equations; using residue number system (RNS) arithmetic operations to respectively determine a plurality of solutions for said plurality of polynomial equations, said plurality of solutions iteratively computed and expressed as RNS residue values; and determining a series of digits in a weighted number system based on said plurality RNS residue values; modulating, at said transmitter, said carrier in a chaotic manner using said string of discrete time chaotic samples, each of said discrete time chaotic samples having a shorter sample time interval than a duration of said plurality of information symbols; utilizing, at said transmitter, an accurate time reference to minimize a timing difference uncertainty between each said string of discrete time chaotic samples generated at said transmitter and said receiver; synchronizing, at said receiver, each said string of discrete time chaotic samples in time and frequency; and maintaining synchronization of said string of discrete time chaotic samples in time and frequency at each said transmitter and said receiver for a duration of an information transfer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A system, comprising:
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a channel encoder configured for channel encoding a carrier responsive to a plurality of information symbols; a chaotic sequence generator configured for generating a continuous string of discrete time samples, each of said discrete time samples having a shorter sample time interval than a duration of said plurality of information symbols, said chaotic sequence generator comprising at least one first processor configured for using residue number system (RNS) arithmetic operations to respectively determine a plurality of solutions for a plurality of polynomial equations, said plurality of solutions iteratively computed and expressed as RNS residue values, and determining a series of digits in a weighted number system based on said plurality of RNS residue values; a multiplier operatively coupled to said chaotic sequence generator and said channel encoder, said multiplier configured for modulating said carrier in a chaotic manner using said string of discrete time samples; an accurate time reference configured for minimizing a timing difference uncertainty between said strings of discrete time chaotic samples generated at said transmitter and said receiver; and at least one second processor configured for initially synchronizing said strings of discrete time chaotic samples in time and frequency and for maintaining synchronization of each said string of discrete time chaotic samples in time and frequency at each of said transmitter and said receiver for a duration of an information transfer. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30)
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Specification