Method and apparatus for combining multipath spread-spectrum signals
First Claim
1. A spread-spectrum signal multipath combiner, comprising:
- (a) matched filtering means for detecting an envelope of an input differential phase shift keyed signal communicated over a communication channel;
(b) envelope detector means, operatively coupled to the matched filtering means, for detecting a replica of a multipath echo structure for the communication channel within the detected envelope;
(c) combiner means, operatively coupled to the matched filtering means and the envelope detector means, for combining the input differential phase shift keyed signal with the detected replica of the multipath echo structure for the communication channel such that a multipaten echo structure weighted differential phase shift keyed signal is formed; and
(d) integrator means, operatively coupled to the combiner means, for integrating the multipath echo structure weighted differential phase shift keyed signal over a one symbol period centered on a correlation peak such that power from a plurality of signal paths determines an output data bit.
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Abstract
A method and apparatus for combining multipath spread-spectrum signals are provided. The multipath combining is accomplished by detecting an envelope of an input differential phase shift keyed signal communicated over a communication channel. Subsequently, a replica of a multipath echo structure for the communication channel is detected within the detected envelope. In addition, a multipath echo structure weighted differential phase shift keyed signal with the detected replica of the multipath echo structure for the communication channel. Finally, the multipath echo structure weighted differential phase shift keyed signal is integrated over a one symbol period centered on a correlation peak such that power from a plurality of signal paths determines an output data bit.
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Citations
21 Claims
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1. A spread-spectrum signal multipath combiner, comprising:
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(a) matched filtering means for detecting an envelope of an input differential phase shift keyed signal communicated over a communication channel; (b) envelope detector means, operatively coupled to the matched filtering means, for detecting a replica of a multipath echo structure for the communication channel within the detected envelope; (c) combiner means, operatively coupled to the matched filtering means and the envelope detector means, for combining the input differential phase shift keyed signal with the detected replica of the multipath echo structure for the communication channel such that a multipaten echo structure weighted differential phase shift keyed signal is formed; and (d) integrator means, operatively coupled to the combiner means, for integrating the multipath echo structure weighted differential phase shift keyed signal over a one symbol period centered on a correlation peak such that power from a plurality of signal paths determines an output data bit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A spread-spectrum signal multipath combiner, comprising:
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(a) matched filtering means for detecting an envelope of an input differential phase shift keyed signal from a spread-spectrum signal received from over a communication channel; (b) first delay means, operatively coupled to the matched filtering means, for delaying the input differential phase shift keyed signal by one symbol period; (c) first combiner means, operatively coupled to the matched filtering means and the first delay means, for combining the input differential phase shift keyed signal with the delayed input differential phase shift keyed signal to form a combined input differential phase shift keyed signal (d) square law based envelope detector means, operatively coupled to the matched filtering means, for detecting a replica of a multipath echo structure for the communication channel within the detected envelope; (e) low pass filter being operatively coupled to the square law based envelope detector means, the low pass filter having a cutoff frequency between the frequency of the input differential phase shift keyed signal and a spreading code frequency associated with the input differential phase shift keyed signal; (f) second delay means, operatively coupled to the low pass filter for delaying a low pass filtered detected replica of the multipath echo structure up to one symbol period such that the detected replica of the multipath echo structure is time aligned with the combined input differential phase shift keyed signal; (g) second combiner means, operatively coupled to the first combiner means and the second delay means, for combining the combined input differential phase shift keyed signal with the delayed low pass filtered detected replica of the multipath echo structure for the communication channel such that a multipath echo structure weighted differential phase shift keyed signal is formed; (h) integrator means, operatively coupled to the combiner means, for integrating the multipath echo structure weighted differential phase shift keyed signal over a one symbol period centered on a correlation peak such that power from a plurality of signal paths determines an output data bit; and (i) detector means, operatively coupled to the integrator means, for detecting the output data bit from the integrated multipath echo structure weighted differential phase shift keyed signal.
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13. A spread-spectrum signal multipath combiner, comprising:
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(a) matched filtering means for detecting an envelope of an input differential quadrature phase shift keyed signal communicated over a communication channel; (b) envelope detector means, operatively coupled to the matched filtering means, for detecting a replica of a multipath echo structure for the communication channel within the detected envelope; (c) first combiner means, operatively coupled to the matched filtering means and the envelope detector means, for combining an I-channel component of the input differential quadrature phase shift keyed signal with the detected replica of the multipath echo structure for the communication channel such that a multipath echo structure weighted I-channel differential quadrature phase shift keyed signal is formed; (d) first integrator means, operatively coupled to the first combiner means, for integrating the multipath echo structure weighted I-channel differential phase shift keyed signal over a one symbol period centered on a correlation peak such that power from a plurality of signal paths determines an output I-channel data bit; (e) second combiner means, operatively coupled to the matched filtering means and the envelope detector means, for combining a Q-channel component of the input differential quadrature phase shift keyed signal with the detected replica of the multipath echo structure for the communication channel such that a multipath echo structure weighted Q-channel differential quadrature phase shift keyed signal is formed; and (f) second integrator means, operatively coupled to the first combiner means, for integrating the multipath echo structure weighted Q-channel differential phase shift keyed signal over a one symbol period centered on a correlation peak such that power from a plurality of signal paths determines an output Q-channel data bit. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21)
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Specification