Adaptive vector correlator using weighting signals for spread-spectrum communications
First Claim
1. A pilot adaptive vector correlator for correcting phase rotation of a plurality of received-multipath signals of a spread-spectrum signal having a pilot-spreading-code signal, comprising:
- pilot-despreading means for generating a plurality of replicas of the pilot-spreading-code signal, with each of the plurality of replicas of the pilot-spreading-code signal having a different phase, said pilot-despreading means for despreading, using the plurality of replicas of the pilot-spreading-code signal, the plurality of received-multipath signals of the spread-spectrum signal as a plurality of despread-multipath signals;
said pilot-despreading means thereby generating a noise-power level when each pilot-spreading-code signal embedded in each of the plurality of received-multipath signals of the spread-spectrum signal is not in phase with any of the plurality of replicas of the pilot-spreading-code signal;
said pilot-despreading means thereby generating one or more detected-pilot signals, when one or more pilot-spreading-code signals embedded in the received-multipath signals of the spread-spectrum signal is in phase with one or more of the plurality of replicas of the pilot-spreading-code signal, respectively;
a pilot adder for combining a plurality of weighted-despread-multipath signals, as a combined-pilot signal;
phase-locked means, coupled to said pilot adder, for phase locking to the combined-pilot signal and for generating, from the phase-locked combined-pilot signal, a derotation-phaser signal;
correction means, coupled between said pilot-despreading means, said phase-locked means and said pilot adder, for multiplying and filtering each of the plurality of despread-multipath signals by the derotation-phaser signal, thereby generating a plurality of weighting signals, respectively;
said correction means for multiplying the plurality of despread-multipath signals by the plurality of weighting signals, to generate the plurality of weighted-despread-multipath signals, respectively;
acquisition-decision means, coupled to said pilot-despreading means, responsive to the one or more detected-pilot signals from said pilot-despreading means, for determining whether the one or more detected-pilot signals are synchronized to one or more of the plurality of replicas of the pilot-spreading-code signal;
said acquisition-decision means, responsive to detecting no synchronization, for sending a control signal to said pilot-despreading means, for offsetting the phase of one or more of the plurality of replicas of the pilot-spreading-code signals; and
said acquisition-decision means, responsive to detecting synchronization, for maintaining synchronization between the plurality of received-multipath signals and the plurality of replicas of the pilot-spreading-code signal.
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Accused Products
Abstract
A pilot adaptive vector correlator for estimating channel-impulse response and for obtaining a reference value of received multipath signals in a spread-spectrum system. A code generator generates a plurality of replicas of a pilot-spreading-code signal, with each replica of the pilot-spreading-code signal having a different phase from other replicas in a plurality of replicas of pilot-spreading-code signals. Each correlator in a plurality of correlators uses a replica of the pilot-spreading-code signal with a different phase from the other correlators in the plurality of correlators. The plurality of correlators correlates the spread-spectrum signal with the plurality of replicas of the pilot-spreading-code signals. The plurality of correlators generates a noise-power level when a pilot-spreading-code signal is not in phase with a replica of the pilot-spreading-code signal, and a pilot signal-power level plus noise-power level when a pilot-spreading-code signal is in phase with a replica of the pilot-spreading-code signal. Using the detected-pilot signal and output signals from the plurality of correlators, a derotation-phaser circuit generates a derotation-phaser signal. Using the derotation-phaser signal, a correction circuit corrects the despread, multipath signals for effects of carrier-phase rotation.
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Citations
18 Claims
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1. A pilot adaptive vector correlator for correcting phase rotation of a plurality of received-multipath signals of a spread-spectrum signal having a pilot-spreading-code signal, comprising:
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pilot-despreading means for generating a plurality of replicas of the pilot-spreading-code signal, with each of the plurality of replicas of the pilot-spreading-code signal having a different phase, said pilot-despreading means for despreading, using the plurality of replicas of the pilot-spreading-code signal, the plurality of received-multipath signals of the spread-spectrum signal as a plurality of despread-multipath signals;
said pilot-despreading means thereby generating a noise-power level when each pilot-spreading-code signal embedded in each of the plurality of received-multipath signals of the spread-spectrum signal is not in phase with any of the plurality of replicas of the pilot-spreading-code signal;
said pilot-despreading means thereby generating one or more detected-pilot signals, when one or more pilot-spreading-code signals embedded in the received-multipath signals of the spread-spectrum signal is in phase with one or more of the plurality of replicas of the pilot-spreading-code signal, respectively;
a pilot adder for combining a plurality of weighted-despread-multipath signals, as a combined-pilot signal;
phase-locked means, coupled to said pilot adder, for phase locking to the combined-pilot signal and for generating, from the phase-locked combined-pilot signal, a derotation-phaser signal;
correction means, coupled between said pilot-despreading means, said phase-locked means and said pilot adder, for multiplying and filtering each of the plurality of despread-multipath signals by the derotation-phaser signal, thereby generating a plurality of weighting signals, respectively;
said correction means for multiplying the plurality of despread-multipath signals by the plurality of weighting signals, to generate the plurality of weighted-despread-multipath signals, respectively;
acquisition-decision means, coupled to said pilot-despreading means, responsive to the one or more detected-pilot signals from said pilot-despreading means, for determining whether the one or more detected-pilot signals are synchronized to one or more of the plurality of replicas of the pilot-spreading-code signal;
said acquisition-decision means, responsive to detecting no synchronization, for sending a control signal to said pilot-despreading means, for offsetting the phase of one or more of the plurality of replicas of the pilot-spreading-code signals; and
said acquisition-decision means, responsive to detecting synchronization, for maintaining synchronization between the plurality of received-multipath signals and the plurality of replicas of the pilot-spreading-code signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
message-despreading means for generating a plurality of replicas of the message-spreading-code signal, with the plurality of replicas of the message-spreading-code signal synchronized to the plurality of replicas of the pilot-spreading code signal, with each of the plurality of replicas of the message-spreading-code signal having a different phase, said message-despreading means for despreading, using the plurality of replicas of the message-spreading-code signal, the plurality of received-message-multipath signals of the message-spread-spectrum signal as a plurality of despread-message-multipath signals;
said message-despreading means thereby generating one or more detected-message signals, when one or more message-spreading-code signals embedded in the received-message-multipath signals of the message-spread-spectrum signal is in phase with one or more of the plurality of replicas of the message-spreading-code signal, respectively;
message-correction means, coupled to said pilot-correction means, for multiplying the plurality of despread-message-multipath signals by the plurality of weighting signals, to generate a plurality of weighted-despread-message signals, respectively; and
a message adder for combining the plurality of weighted-despread-message signals as a combined-message.
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3. The pilot adaptive vector correlator as set forth in claim 1 or 2, with said pilot despreading means including:
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a code generator for generating the plurality of replicas of the pilot-spreading-code signal;
a plurality of correlators, coupled to said code generator, with each of the plurality of correlators using one of the plurality of replica of the pilot-spreading-code signal, said plurality of correlators for correlating the spread-spectrum signal with the plurality of replicas of the pilot-spreading-code signal;
said plurality of correlators thereby generating the noise-power level when each pilot-spreading-code signal embedded in each of the plurality of received-multipath signals of the spread-spectrum signal is not in phase with any of the plurality of replicas of the pilot-spreading-code signal; and
said plurality of correlators for generating one or more detected-pilot signals and the noise-power level, when one or more pilot-spreading-code signals embedded in the received-multipath signals of the spread-spectrum signal is in phase with one or more of the plurality of replicas of the pilot-spreading-code signal, respectively.
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4. The adaptive vector correlator as set forth in claim 1 or 2, with said pilot despreading means including a plurality of correlators for correlating the spread-spectrum signal with a plurality of phases of the plurality of replicas of the pilot-spreading-code signal, respectively.
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5. The adaptive vector correlator as set forth in claim 1 or 2, with said pilot adder including means for adding the plurality of weighted-despread-multipath signals as the combined-pilot signal.
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6. The adaptive vector correlator as set forth in claim 3, with said pilot adder including means for adding the plurality of weighted-despread-multipath signals as the combined-pilot signal.
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7. The adaptive vector correlator as set forth in claim 4, with said pilot adder including means for adding the plurality of weighted-despread-multipath signals as the combined-pilot signal.
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8. The adaptive vector correlator as set forth in claim 2, with said message adder including means for adding the plurality of weighted-despread-message signals as the combined-message signal.
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9. The adaptive vector correlator as set forth in claim 3, with said message adder including means for adding the plurality of weighted-despread-message signals as the combined-message signal.
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10. The adaptive vector correlator as set forth in claim 4, with said message adder including means for adding the plurality of weighted-despread-message signals as the combined-message signal.
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11. A pilot adaptive vector correlator for correcting phase rotation of a plurality of received multipath signals of a spread-spectrum signal having a pilot-spreading-code signal, comprising:
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a pilot-code generator for generating a plurality of replicas of the pilot-spreading-code signal, with each of the plurality of replicas of the pilot-spreading-code signal having a different phase;
a plurality of pilot-correlators, coupled to said pilot-code generator, for despreading, using the plurality of replicas of the pilot-spreading-code signal, the plurality of received-multipath signals of the spread-spectrum signal as a plurality of despread-multipath signals;
said plurality of pilot-correlators thereby generating a noise-power level when each pilot-spreading-code signal embedded in each of the plurality of received-multipath signals of the spread-spectrum signal is not in phase with any of the plurality of replicas of the pilot-spreading-code signal;
said plurality of pilot-correlators thereby generating one or more detected-pilot signals, when one or more pilot-spreading-code signals embedded in the received-multipath signals of the spread-spectrum signal is in phase with one or more of the plurality of replicas of the pilot-spreading-code signal, respectively;
a pilot adder for combining a plurality of weighted-despread-multipath signals, as a combined-pilot signal;
a phase-locked-loop (PLL) circuit, coupled to said pilot adder, for phase locking to the combined-pilot signal and for generating, from the phase-locked combined-pilot signal, a derotation-phaser signal;
a correction circuit, coupled between said plurality of pilot-correlators, said PLL circuit and said pilot adder, for multiplying and filtering each of the plurality of despread-multipath signals by the derotation-phaser signal, to generate a plurality of weighting signals, respectively;
said correction circuit for multiplying the plurality of despread-multipath signals by the plurality of weighting signals, to generate the plurality of weighted-despread-multipath signals, respectively;
an acquisition-decision circuit, coupled to said plurality of pilot-correlators, responsive to the one or more detected-pilot signals from said plurality of pilot-correlators, for determining whether the one or more detected-pilot signals are synchronized to one or more of the plurality of replicas of the pilot-spreading-code signal;
said acquisition-decision circuit, responsive to detecting no synchronization, for sending a control signal to said plurality of pilot-correlators, for offsetting the phase of one or more of the plurality of replicas of the pilot-spreading-code signals; and
said acquisition-decision circuit, responsive to detecting synchronization, for maintaining synchronization between the plurality of received-multipath signals and the plurality of replicas of the pilot-spreading-code signal. - View Dependent Claims (12, 13, 14)
a message-code generator for generating a plurality of replicas of the message-spreading-code signal, with the plurality of replicas of the message-spreading-code signal synchronized to the plurality of replicas of the pilot-spreading code signal, with each of the plurality of replicas of the message-spreading-code signal having a different phase;
a plurality of message correlators, coupled to said message-code generator, for despreading, using the plurality of replicas of the message-spreading-code signal, the plurality of received-message-multipath signals of the message-spread-spectrum signal as a plurality of despread-message-multipath signals;
said plurality of message correlators thereby generating one or more detected-message signals, when one or more message-spreading-code signals embedded in the received-message-multipath signals of the message-spread-spectrum signal is in phase with one or more of the plurality of replicas of the message-spreading-code signal, respectively;
a message-correction circuit, coupled to said plurality of message correlators, for multiplying the plurality of despread-message-multipath signals by the plurality of weighting signals, to generate a plurality of weighted-despread-message signals, respectively; and
a message adder for combining the plurality of weighted-despread-message signals as a combined-message.
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13. The adaptive vector correlator as set forth in claim 11 or 12, with said pilot adder including means for adding the plurality of weighted-despread-multipath signals as the combined-pilot signal.
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14. The pilot adaptive vector correlator as set forth in claim 11 or 12, with said message adder including means for adding the plurality of weighted-despread-message signals as the combined-message signal.
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15. A pilot adaptive vector correlation method for correcting phase rotation of a plurality of received multipath signals of a spread-spectrum signal having a pilot-spreading-code signal, comprising the steps of:
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generating a plurality of replicas of the pilot-spreading-code signal, with each of the plurality of replicas of the pilot-spreading-code signal having a different phase;
despreading, using the plurality of replicas of the pilot-spreading-code signal, the plurality of received-multipath signals of the spread-spectrum signal as a plurality of despread-multipath signals;
generating a noise-power level when each pilot-spreading-code signal embedded in each of the plurality of received-multipath signals of the spread-spectrum signal is not in phase with any of the plurality of replicas of the pilot-spreading-code signal;
generating one or more detected-pilot signals, when one or more pilot-spreading-code signals embedded in the received-multipath signals of the spread-spectrum signal is in phase with one or more of the plurality of replicas of the pilot-spreading-code signal, respectively;
combining a plurality of weighted-despread-multipath signals, as a combined-pilot signal;
phase locking to the combined-pilot signal;
generating, from the phase-locked combined-pilot signal, a derotation-phaser signal;
multiplying and filtering each of the plurality of despread-multipath signals by the derotation-phaser signal, to generate a plurality of weighting signals, respectively;
multiplying the plurality of despread-multipath signals by the plurality of weighting signals, to generate the plurality of weighted-despread-multipath signals, respectively;
determining, from the one or more detected-pilot signals, whether the one or more detected-pilot signals are synchronized to one or more of the plurality of replicas of the pilot-spreading-code signal;
sending, in response to detecting no synchronization, a control signal for offsetting the phase of one or more of the plurality of replicas of the pilot-spreading-code signals; and
maintaining, in response to detecting synchronization, synchronization between the plurality of received-multipath signals and the plurality of replicas of the pilot-spreading-code signal. - View Dependent Claims (16, 17, 18)
generating a plurality of replicas of the message-spreading-code signal, with the plurality of replicas of the message-spreading-code signal synchronized to the plurality of replicas of the pilot-spreading code signal, with each of the plurality of replicas of the plurality of replicas of the message-spreading-code signal having a different phase;
despreading, using the plurality of replicas of the message-spreading-code signal, the plurality of received-message-multipath signals of the message-spread-spectrum signal as a plurality of despread-message-multipath signals;
generating one or more detected-message signals, when one or more message-spreading-code signals embedded in the received-message-multipath signals of the message-spread-spectrum signal is in phase with one or more of the plurality of replicas of the message-spreading-code signal, respectively;
multiplying the plurality of despread-message-multipath signals by the plurality of weighting signals, to generate a plurality of weighted-despread-message signals, respectively; and
combining the plurality of weighted-despread-message signals as a combined-message.
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17. The method as set forth in claim 15 or 16, with the step of combining the plurality of weighted-despread-multipath signals as a combined-pilot further including the step of adding the plurality of weighted-despread-multipath signals as a combined-pilot signal.
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18. The method as set forth in claim 15 or 16, with the step of combining the plurality of weighted-despread-message signals as a combined-message further including the step of adding the plurality of weighted-despread-message signals as a combined-message.
Specification