Ultra wide bandwidth spread-spectrum communications systems
First Claim
1. A data communications method, comprising:
- receiving an input of high-speed digital data for communication;
repetitively generating a codeword to produce a digital code signal;
modulating the digital code signal in accord with the high-speed 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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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.
180 Citations
42 Claims
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1. A data communications method, comprising:
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receiving an input of high-speed digital data for communication;
repetitively generating a codeword to produce a digital code signal;
modulating the digital code signal in accord with the high-speed 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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A data communications method, comprising:
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receiving an input of high-speed digital data for communication;
processing the high-speed digital data;
generating a code modulated digital signal responsive to the processed high speed data;
generating a sequence of short impulse wavelets;
processing the sequence of short impulse wavelets in response to the processed high speed data so as to produce a modulated ultrawideband impulse signal, wherein the sequence of short impulse wavelets in the modulated ulrawideband signal is modulated in accord with bits of the code modulated digital signal; and
transmitting the modulated ultrawideband impulse signal. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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26. An ultrawideband impulse transmitter, for transmitting high-speed digital data for communication, comprising:
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an input for receiving the high-speed digital data for communication;
a code generator for generating a digital code signal, the digital code signal comprising a repetitive codeword;
a gate responsive to a stream of bits obtained in response to the high-speed digital data and coupled to the code generator, for modulating the digital code signal in accord with the stream of bits;
at least one impulse generator, for generating short impulse wavelets; and
a selector responsive to the modulated digital code signal and coupled to the at least one impulse generator, wherein the at least one impulse generator and the selector produce a modulated ultrawideband impulse signal comprising a sequence of the short impulse wavelets modulated in accord with the modulated digital code signal. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34)
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35. A method of receiving high-speed data via ultrawideband impulse communication, comprising:
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receiving a modulated ultrawideband impulse signal transmitted from a remote location, wherein the received modulated ultrawideband impulse signal comprises a sequence of short impulse wavelets modulated in accord with a code signal, the code signal being digitally modulated with the bits obtained from the high-speed data;
generating a local code signal comprising a repeating codeword;
generating a local modulated ultrawideband impulse signal in response to the local code signal, wherein the local modulated impulse signal comprises a local sequence of short impulse wavelets, and the local sequence of short impulse wavelets is modulated in accord with bits of the local code signal;
locking timing of the local modulated ultrawideband impulse signal to the received modulated ultrawideband impulse signal; and
correlating the locked local modulated ultrawideband impulse signal to the received modulated ultrawideband impulse signal to detect the bits obtained from the high-speed data in the received modulated ultrawideband impulse signal. - View Dependent Claims (36, 37, 38, 39, 40)
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41. An ultrawideband impulse receiver, for receiving high-speed digital data, comprising:
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a receiver from end for receiving a modulated ultrawideband impulse signal transmitted from a remote location, wherein the received modulated ultrawideband impulse signal comprises a sequence of short impulse wavelets modulated in accord with a code signal, the code signal being digitally modulated with bits corresponding to the high-speed data; and
means for demodulating the received modulated ultrawideband impulse signal to recover bits corresponding to the high-speed digital data, wherein the means for demodulating comprises;
means for generating a local ultrawideband impulse signal; and
a delay lock loop for locking timing of the local ultrawideband impulse signal to timing of the received modulated ultrawideband impulse signal, and for using the locked local ultrawideband impulse signal to recover the bits corresponding to the high-speed digital data from the received modulated ultrawideband impulse signal.
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42. A data communications method, comprising:
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a step for receiving an input of high-speed digital data for communication;
a step for repetitively generating a codeword to produce a digital code signal;
a step for modulating the digital code signal in accord with the high-speed digital data, to generate a modulated code signal;
a step for 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
a step for outputting the modulated ultrawideband impulse signal.
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Specification