Method and apparatus for multipath demodulation in a code division multiple access communication system
First Claim
Patent Images
1. An apparatus for receiving multiple spread spectrum signals each traveling upon a different propagation path and each having a resultant arrival time difference with respect to one another, comprising:
- a first demodulator for demodulating a first spread spectrum signal of said multiple spread spectrum signals in accordance with a first arrival time; and
a second demodulator for demodulating a second spread spectrum signal of said multiple spread spectrum signals in accordance with a time interval difference with respect to said first arrival times,wherein said first demodulator comprises;
a pseudorandom noise descrambler for descrambling said first spread spectrum signal in accordance with a pseudorandom noise sequence;
a phase adjustor for extracting a pilot signal from said descrambled first spread spectrum signal and multiplying said descrambled first spread spectrum signal with said extracted pilot signal, thereby forming a phase adjusted signal; and
a dechannelization unit for multiplying said phase adjusted signal by an orthogonal channel sequence.
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Abstract
Multipath RAKE receiver structure that allows for the concurrent demodulation of multipath signals that arrive at the receiver at arbitrarily low arrival time differences. The fingers are set to be a fixed offset from one another. One finger tracks the shift in the peak of the multipath component and the additional fixed offset fingers follow the tracking.
35 Citations
14 Claims
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1. An apparatus for receiving multiple spread spectrum signals each traveling upon a different propagation path and each having a resultant arrival time difference with respect to one another, comprising:
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a first demodulator for demodulating a first spread spectrum signal of said multiple spread spectrum signals in accordance with a first arrival time; and a second demodulator for demodulating a second spread spectrum signal of said multiple spread spectrum signals in accordance with a time interval difference with respect to said first arrival times, wherein said first demodulator comprises; a pseudorandom noise descrambler for descrambling said first spread spectrum signal in accordance with a pseudorandom noise sequence; a phase adjustor for extracting a pilot signal from said descrambled first spread spectrum signal and multiplying said descrambled first spread spectrum signal with said extracted pilot signal, thereby forming a phase adjusted signal; and a dechannelization unit for multiplying said phase adjusted signal by an orthogonal channel sequence. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for receiving multiple spread spectrum signals each traveling upon a different propagation path and each having a resultant arrival time difference with respect to one another, said method comprising the steps of:
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demodulating a first spread spectrum signal of said multiple spread spectrum signals in accordance with a first arrival time; and demodulating a second spread spectrum signal of said multiple spread spectrum signals in accordance with a time interval difference with respect to said first arrival times, wherein said step of demodulating said first spread spectrum signal comprises the steps of; descrambling said first spread spectrum signal in accordance with a pseudorandom noise sequence; extracting a pilot signal from said descrambled first spread spectrum signal; multiplying said descrambled first spread spectrum signal with said extracted pilot signal, thereby forming a phase adjusted signal; and multiplying said phase adjusted signal by an orthogonal channel sequence. - View Dependent Claims (8, 9, 10)
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11. An apparatus for receiving multiple spread spectrum signals each traveling upon a different propagation path and each having a resultant arrival time difference with respect to one another, said apparatus comprising:
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means for demodulating a first spread spectrum signal of said multiple spread spectrum signals in accordance with a first arrival time; and means for demodulating a second spread spectrum signal of said multiple spread spectrum signals in accordance with a time interval difference with respect to said first arrival times, wherein said means for demodulating said first spread spectrum signal comprises; means for descrambling said first spread spectrum signal in accordance with a pseudorandom noise sequence; means for extracting a pilot signal from said descrambled first spread spectrum signal; means for multiplying said descrambled first spread spectrum signal with said extracted pilot signal, thereby forming a phase adjusted signal; and means for multiplying said phase adjusted signal by an orthogonal channel sequence. - View Dependent Claims (12, 13, 14)
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Specification