Communication system employing chaotic sequence based frequency shift keying spreading signals
First Claim
1. An apparatus for generating a communications signal, the apparatus comprising:
- a pseudorandom number generator for providing a sequence of pseudorandom phase words;
a mapping module coupled with an output of the pseudorandom number generator, the mapping module including a color mapping table containing phase value information, wherein the mapping module provides an output phase word sequence by phase mapping the sequence of pseudorandom phase words in accordance with the phase value information; and
a modulator coupled with an output of the mapping module, the modulator including a phase mapper, followed by a spreader and a band-limiting filter, wherein the modulator is operative to generate the communications signal using the output phase word sequence, and wherein a frequency domain spectrum of the communications signal is determined in accordance with the phase value information.
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Abstract
A candidate arbitrary-phase spread spectrum modulation technique that offers similar performance to spread continuous phase modulation (CPM) waveforms and additional capabilities for programming a chosen frequency domain spectra into the resulting spread spectrum signal. The proposed chaotic-FSK waveform is derived from high-order sequence-based spread spectrum signals, with multi-bit resolution chaos-based sequences defining incremental phase words, enabling real-time efficient generation of practically non-repeating waveforms. A result of the C-FSK formulation is a parameterized hybrid modulation capable of acting like a traditional sequence-based spread spectrum signal or a traditional frequency shift keying signal depending on chosen parameters. As such, adaptation in this modulation may be easily implemented as a time-varying evolution, increasing the security of the waveform while retaining many efficiently implementable receiver design characteristics of traditional PSK modulations.
7 Citations
30 Claims
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1. An apparatus for generating a communications signal, the apparatus comprising:
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a pseudorandom number generator for providing a sequence of pseudorandom phase words; a mapping module coupled with an output of the pseudorandom number generator, the mapping module including a color mapping table containing phase value information, wherein the mapping module provides an output phase word sequence by phase mapping the sequence of pseudorandom phase words in accordance with the phase value information; and a modulator coupled with an output of the mapping module, the modulator including a phase mapper, followed by a spreader and a band-limiting filter, wherein the modulator is operative to generate the communications signal using the output phase word sequence, and wherein a frequency domain spectrum of the communications signal is determined in accordance with the phase value information. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A transmitter, comprising:
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an encoder for generating encoded data symbols based upon input data provided by a data source; a communications signal generator including; a pseudorandom number generator for providing a sequence of pseudorandom phase words; a mapping module coupled with an output of the pseudorandom number generator, the mapping module including a color mapping table containing phase value information, wherein the mapping module provides an output phase word sequence by phase mapping the sequence of pseudorandom phase words in accordance with the phase value information; a modulator coupled with an output of the mapping module, the modulator including a phase mapper, followed by a spreader and a band-limiting filter, wherein the modulator generates a spreading sequence using the output phase word sequence, and wherein a frequency domain spectrum of the spreading sequence is determined in accordance with the phase value information; and a transmit signal generator for generating a transmit signal by spreading the encoded data symbols using the spreading sequence. - View Dependent Claims (14)
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15. A transceiver apparatus, comprising:
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a receiver including a channel state information module coupled with an antenna via at least one of a Fast Fourier Transform module (FFT) or a received signal strength indicator (RSSI), wherein the channel state information module derives channel state information from a received signal; a color mapping table storing phase value information wherein the phase value information is determined based at least in part upon the channel state information; and a communications signal generator configured to generate a communications waveform, the communications signal generator including a mapping module operative to introduce a selected frequency domain spectra into the communications waveform in accordance with the phase value information. - View Dependent Claims (16)
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17. A method for generating a communications signal, the method comprising:
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providing a sequence of pseudorandom phase words; generating a color mapping table containing phase value information; providing an output phase word sequence by phase mapping the sequence of pseudorandom phase words in accordance with the phase value information; and generating the communications signal using the output phase word sequence wherein a frequency domain spectrum of the communications signal is determined in accordance with the phase value information. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. A method, comprising:
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generating encoded data symbols based upon input data provided by a data source;
providing a sequence of pseudorandom phase words;generating a color mapping table containing phase value information; providing an output phase word sequence by phase mapping the sequence of pseudorandom phase words in accordance with the phase value information; generating a spreading sequence using the output phase word sequence wherein a frequency domain spectrum of the spreading sequence is determined in accordance with the phase value information; and generating a transmit signal by spreading the encoded data symbols using the spreading sequence. - View Dependent Claims (28)
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29. A method, comprising:
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providing channel state information based upon a received signal, wherein the state information is derived from at least one of (a) frequency domain information provided by a Fast Fourier Transform (FFT) module or (b) received signal strength information provided by a received signal strength indicator (RSSI) module; storing phase value information in a color mapping table, wherein the phase value information is determined based at least in part upon the channel state information; and
generating, in accordance with the phase value information, a communications waveform having a selected frequency domain spectrum determined by the phase value information. - View Dependent Claims (30)
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Specification