Ultra wide bandwidth spread-spectrum communications system
First Claim
1. A data communications method, comprising:
- receiving a stream of digital data;
repetitively generating a codeword to produce a digital code signal;
modulating the codeword digital code signal in accord with the digital data, to generate a modulated code signal;
generating a modulated ultrawideband impulse signal in response to the modulated code signal, wherein;
(a) the modulated ultrawideband impulse signal comprises a sequence of short impulse wavelets, and (b) the sequence of short impulse wavelets is modulated in accord with bits of the modulated code signal; and
outputting the modulated ultrawideband impulse signal.
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Accused Products
Abstract
An ultra wide bandwidth, high speed, spread spectrum communications system uses short wavelets of electromagnetic energy to transmit information through objects such as walls or earth. The communication system uses baseband codes formed from time shifted and inverted wavelets to encode data on a RF signal. Typical wavelet pulse durations are on the order of 100 to 1000 picoseconds with a bandwidth of approximately 8 GHz to 1 GHz, respectively. The combination of short duration wavelets and encoding techniques are used to spread the signal energy over an ultra wide frequency band such that the energy is not concentrated in any particular narrow band (e.g. VHF: 30-300 MHz or UHF: 300-1000 MHz) and is not detected by conventional narrow band receivers so it does not interfere with those communication systems. The use of pulse codes composed of time shifted and inverted wavelets gives the system according to the present invention has a spatial resolution on the order of 1 foot which is sufficient to minimize the negative effects of multipath interference and permit time domain rake processing.
108 Citations
45 Claims
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1. A data communications method, comprising:
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receiving a stream of digital data;
repetitively generating a codeword to produce a digital code signal;
modulating the codeword digital code signal in accord with the digital data, to generate a modulated code signal;
generating a modulated ultrawideband impulse signal in response to the modulated code signal, wherein;
(a) the modulated ultrawideband impulse signal comprises a sequence of short impulse wavelets, and (b) the sequence of short impulse wavelets is modulated in accord with bits of the modulated code signal; and
outputting the modulated ultrawideband impulse signal.
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2-44. -44. (canceled)
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45. A data communications method, comprising:
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receiving a stream of digital data that are mapped such that a first data value corresponds to a positive value and a second data value corresponds to a negative data value;
repetitively generating a codeword to produce a digital code signal;
modulating the codeword digital code signal by either the positive value or the negative value in accord with the digital data, to generate a modulated code signal;
generating a modulated ultrawideband impulse signal by modulating the modulated code signal with a pulse shape; and
outputting the modulated ultrawideband impulse signal.
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Specification