Multipath diversity spread spectrum receiver
First Claim
Patent Images
1. A multipath diversity spread spectrum receiver for receiving spread spectrum signals, comprising:
- detector means for detecting the spread spectrum signals and to provide a stream of correlation pulses that relate to transmitted data;
integrator means for decision directed coherent integrating the stream of correlation pulses including;
normalizer means for normalizing the stream of correlation pulses to obtain a stream of normalized pulses,first summing means for summing each member of the stream of normalized pulses with a corresponding member of a stream of output pulses to obtain a stream of combination pulses,delay register means for delaying each member of the stream of combination pulses one symbol period to obtain the stream of output pulses, andfeedback path means for connecting the stream of output pulses to the summing means; and
first data detector means for decoding the transmitted data from the stream of output pulses to obtain a stream of detected data symbols.
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Abstract
A multipath diversity spread spectrum communications receiver will enhance system performance over communication channels with distortion caused by multipath and fading effects. The multipath diversity receiver utilizes decision directed coherent integration with post detection correlation techniques for performance enhancement. The receiver also incorporates a fast attack, fast release automatic gain control to process noncontinuous wideband spread spectrum signals which are subject to fading and multipath effects.
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Citations
13 Claims
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1. A multipath diversity spread spectrum receiver for receiving spread spectrum signals, comprising:
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detector means for detecting the spread spectrum signals and to provide a stream of correlation pulses that relate to transmitted data; integrator means for decision directed coherent integrating the stream of correlation pulses including; normalizer means for normalizing the stream of correlation pulses to obtain a stream of normalized pulses, first summing means for summing each member of the stream of normalized pulses with a corresponding member of a stream of output pulses to obtain a stream of combination pulses, delay register means for delaying each member of the stream of combination pulses one symbol period to obtain the stream of output pulses, and feedback path means for connecting the stream of output pulses to the summing means; and first data detector means for decoding the transmitted data from the stream of output pulses to obtain a stream of detected data symbols. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An automatic gain control apparatus for a radio receiver comprising, in cascade arrangement:
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a variable gain controlled amplifier; detector means for detecting a spread spectrum signal and to provide a stream of correlation pulses that relate to transmitted data; integrator means for performing decision directed coherently integration or the stream of correlation pulses including; normalizer means for normalizing the correlation pulses to obtain a stream of normalized pulses; first summing means for summing the normalized pulses with a stream of output pulses to obtain a stream of combination pulses, delay register means for delaying the stream of combination pulses one symbol period to provide the stream of output pulses, and feedback path means for connecting the stream of output pulses to the summing means; second summing means for performing a parallel summation of the contents of the delay register to obtain a first output signal; and means for connecting the first output signal to said variable gain controlled amplifier whereby the variable gain controlled amplifier adjusts its gain in response to the first output signal. - View Dependent Claims (8, 9, 10)
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11. A method of automatically adjusting a signal plus noise, comprising:
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controlling the gain of a variable gain amplifier with a subsequent generated error signal; detecting the spread spectrum signals and providing a stream of correlation pulses that relate to transmitted data; decision directed coherently integrating the stream of correlation pulses including the steps of; normalizing the stream of correlation pulses to obtain a stream of normalizing pulses, summing each member of the stream of normalized pulses with a corresponding member of a stream of output pulses to obtain a stream of combination pulses, delaying each member of the stream of combination pulses one symbol period to obtain the stream of output pulses thereby, and decoding the transmitted data from the output pulses to obtain a stream of detected data symbols.
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12. A multipath diversity spread spectrum receiver for receiving spread spectrum signals, comprising:
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detector means for detecting the spread spectrum signals and to provide a first stream of correlation pulses and a second stream of correlation pulses that has a quadrature relationship with the first stream of correlation pulses and each stream of correlation pulses relates to transmitted data; integrator means for decision directed coherently integrating the first stream of correlation pulses including; first multiplier means for multiplying the first stream of correlation pulses with a first stream of data symbols to obtain a first stream of combination pulses, delay register means for delaying each member of the first stream of combination pulses one symbol period to provide a first stream of output pules, and normalizer means for normalizing the first stream of output pulses to obtain a stream of normalized pulses, first data detector means for decoding a first phase of transmitted data from the stream of normalized pulses and the first stream of correlation pulses to obtain a first stream of data symbols; and second data detector means for decoding a second phase of transmitted data from the stream of normalized pulses and the second stream of correlation pulses to obtain a second stream of data symbols.
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13. A multipath diversity spread spectrum receiver for receiving spread spectrum signals, comprising:
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detector means for detecting the spread spectrum signals and to provide a first stream of correlation pulses and a second stream of correlation pulses which has a quadrature relationship with the first stream of correlation pulses and each stream relates to the transmitted data; integrator means for decision directed coherently integrating the first stream of correlation pulses including; first time delay means for delaying the first stream of correlation pulses one symbol period to obtain a first stream of delayed pulses, first multiplier means for multiplying the first stream of delayed pulses with a first stream of data symbols to obtain a first stream of product pulses, second time delay means for delaying the second stream of correlation pulses one symbol period to obtain a second stream of delayed pulses, second multiplier means for multiplying the second stream of delayed pulses with a second stream of data symbols to obtain a second stream of product pulses, first summing means for summing the first stream of product pulses with the second stream of product pulses to obtain a stream of combination pulses, delay register means for delaying each member of the stream of combination pulses one symbol period to provide a stream of output pulses, and normalizer means for normalizing the first stream of output pulses to obtain a stream of normalized pulses; first data detector means for decoding a first phase of transmitted data from the stream of normalized pulses and the first stream of correlation pulses to obtain a first stream of data symbols; second detector means for decoding the second phase of transmitted data from the stream of normalized pulses and the second stream of correlation pulses to obtain a second stream of data symbols; first feedback means for connecting the first stream of data symbols to the first multiplier means; and second feedback for connecting the second stream of data symbols to the second multiplier means.
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Specification